Content Page

1. General 3

2. Advantages of the piston accumulator 4

3. Main applications 5 -6

4. Accumulator sizing 7 - 12

5. Accumulator selection 13 - 14

6. Dimension and components 15 -16

7. Accumulator station 17

8. Additional bottles 18÷20

9. Elements of clamping and sleeve 21

10. Pre-loading and checking set 22 - 23

11. Installation 24

12. Pre-charge and checks 25

13. Maintenance 26

14. Branches and representatives all over the world

General

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General1

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1.1 Definition and Functionality

The piston hydro pneumatic accumulator, is a component used toexchange energy using the hydraulic system to which it is connect-ed. It escapes energy at determined moments, the accumulate inthe form of pressure energy of gas, it readily and integrally replenish-es the system on demand, returning to the conditions of receivingagain.The piston accumulator is particularly constructed with two cham-bers, one of which is filled with gas at opportune pressure, and thesecond one connected to the hydraulic circuit.The gas pressure must be chosen in relation to the conditions ofwork of the accumulator, and constitutes the pre-loading pressure.

1.2 Constructive Characteristics

The piston accumulator consists of a steel cylinder, closed at bothends, in which slide an airtight aluminium piston.This divides the internal of the cylinder in two chambers, one filledwith pre-charge gas and the other with oil, or generally speaking,with fluid from the system (Fig 1).

• The piston is made from aluminium in order to have rapidresponse time and not to generate pressure peaks during rapidcycles. It also has a cavity in order to lighten it, visible in fig 1. fac-ing the gas chamber, in order to increase the volume of accumu-late. Even the surface in contact with the oil has a concave cavi-ty. The purpose of this cavity is so that the oil pressure acts onalmost the entire surface of the piston and not only in one spotwhen the piston is against the bottom end cover in the oil cham-ber

• Seal between piston and cylinder is guaranteed by a specialmulti ring seal, which constitutes the key characteristic elementsto the efficiency of the accumulator. This type of seal has allowedthe piston accumulator to have essential characteristics regardingair lightness, component longevity and stroking. In fact, the differ-ential pressure necessary to move the piston, that relates directlyon the speed of response of the accumulator, is contained in mod-erate values, contrary as occurs in most seals for standard pis-tons.The maximum operating temperature with NBR seals is 80ºC.It is possible to operate at temperatures up to 150ºC, using vitonseals and reduced piston, as the expansion factors of aluminiumand steel are different, it is therefore necessary to compensate thethermo effect.In piston accumulators, the duration and number of operationseffected without evidence of variation in pressure in excess of 5%in the value off the pre-charge surcomes without penetration,above a certain quantities of oil in the gas chamber.It is usually preferable to assume the variation of pre-charge as avaluation of the longevity of the accumulator as long as this checkis carried out fast and simply.Through practical results, obtained from application experience, aswell as laboratory test, it was proved that 1.000.000 operations canbe achieved without maintenance or intervention of recharging.

• The cylinder body of the accumulator is made from low carbonsteel, equivalent to mechanical characteristics of 97/23/CE.The internal surface of the cylinder is honed to 0.2 micron ofroughness.

For particular reasons, the cylinder and end covers can either besuperficially treatment or made from stainless steel.

• The gas side end cover is screwed to the cylinder body, the sealis guaranteed by a toroidal gasket, complete with anti-extrusionring.In the standard version this end cap has a threaded seat in whichthe pre-charged valve is situated.

• The oil side end cover is also screwed to the cylinder body and iscomplete with relative seal.This end cap has a coupling to connect it to the system, eitherthreaded or flanged, in accordance to the clients requirements.

Fig. 1

• All the production of EPE accumulators is integrally tested to PEDstandards.The accumulators are tested at PT pressure which is equal tomaximum working pressure PS, multiplied by 1,43 which allows toverify the absence of defects, capable of causing flaws and defor-mities in the cylinder and piston, or gas or oil leak from the seals,threaded sections or valve.The relieve pressure is in excess of 1 700 bar for model types,designed to work at a maximum pressure of 375 bar.

Advantages of the piston accumulator2

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2.1 Ratio of compression.

The volume of oil that can be stored by an accumulator also dependson the value of compression (Ratio between as and fluid) that theaccumulator can endure. For example if we pre-charge a 35 litre accu-mulator with a pressure of 30 bar and we then full it with oil at a pres-sure of 210 bar we will at the end have 30 litres of oil in the accumu-lator, whilst the gas would result content in a volume of 5 litres. Thecompression ratio in this case 7:1 and be had available 30 liters of oilto the would discharge side of the accumulator. In the case of a blad-der type accumulator, a compression ratio of 7:1 cannot be tolerated(in fact it is recommended not to exceed 4:1) this could cause prema-ture failure of the rubber separation bladder.

2.2 Osmosis

Even if the piston accumulator has a part in motion, it must not beallowed that the gas filters through to the oil, since the pocket type isprone to the phenomenon of osmosis. In applications where the accu-mulator has to remain on pressure for long periods of time (In case ofan emergency) oil can slowly leak through the bladder, up to 10% ofthe pre-charge gas. This would require periodic maintenance in theform of pre-charge or replacement of the bladder itself.

2.3 Storage

To keep a piston accumulator inoperative in storage will not have aharmful effect and does not implicate time problems, if from time totime it is given a pre-charge, to prevent air ingress which could containmoisture which could cause corrosion to the internal of the cylinder.As with the pocket type accumulator it is not advisable to keep it instorage for long periods of time as this could cause the rubber to dete-riorate, even though it is synthetic.

2.4 Volumetric performance

If an accumulator is charged with a certain volume of oil, lets say thatits volumetric performance is equal to the unity, if it should be in a posi-tion to entirely restore the volume in the system in a successiveinstant, in other words, to obtain unitary volumetric performance, anaccumulator must not have dead spaces. In this condition it is similar(Volumetric performance approximately 0,99-0,995). In the pistonaccumulator nothing prevents the piston to reach the end of the stroke,against the oil exit orifice, which cannot be said for bladder type accu-mulators, since a strong charge could cause the membrane to obstructthe oil orifice or deform. It is in fact recommended by the manufactur-ers not to discharge a pocket type accumulator beyond 9/10 of the vol-ume of accumulable oil.

2.5 Assembly position

There does not exist any limitations, assuming any inclinationsbetween vertical and horizontal positions for the EPE Piston accumu-lator, always obtaining the same volumetric performance and function-ality. The same cannot be said for a bladder type accumulator, whichdepends on flexible motion that is affected by gravity. This could pre-vent restitution of all the accumulated oil, which could cause damageto the rubber bladder as a result of uneven distribution of forces.

2.6 Operational Safety

The assurance that a component of a system offers during its opera-tion is essentially based on the functionality of its project and on thesimplicity of its execution, signifying to be able effectively a more pre-cise and severe quality control. A piston accumulator consists of alapped cylinder and a piston with a seal, therefore being the criticalelements, only the condition of the one surface, which is mechanical-ly obtained and the characteristics of a sealing ring, it is possible toachieve the most severe quality standards, with which it offers themaximum operational safety. Whilst with the pocket accumulator,apart from the mechanical components, the most critical point remainsthe rubber diaphragm. This is obtained by press fusion and when thedimensions exceed a certain limit, it becomes very difficult to controlthe quality in the point of view of composition, resistance, imperfec-tions and thickness. The point of concern is that a breakdown in thepocket immediately puts the accumulator out of service with the con-sequence of blocking the all hydraulic system. There is in facet no pre-warning of the breakdown: this is always almost certain to cause fail-ure of the pocket and damage the all surface.It is important to observe, that is the piston accumulator is about tobreakdown, it will start will gradual and progressive leaks, followed bya drop in response speed or efficiency of the unit, as well as a drop inpre-charge pressure. With this, there is ample warning to take neces-sary measures to prevent big consequences.

2.7 Capacity

With the difficulties mentioned above to obtain a perfectly homoge-nized bladder, without imperfection when the dimensions exceed acertain limit, the bladder accumulators have rather low volumetric val-ues: usually 50 litres is the maximum limit. There is no limit for pistonaccumulators, manufactured by EPE with a standard limit of 300 litres.

2.8 Monitoring

With a piston accumulator, it is easy to monitor the position of the pis-ton for the entire or part of its stroke, with the result knowing how muchoil has accumulated, indicated by on-off signals, amalogical or digital,on the control system. This monitoring system, serves to utilize themaximum stroke with the result of obtaining maximum quantity of fluidaccumulated, to action the start and stop of the pump, to indicateanomalies and to visualize the quantity of fluid available.

2.9 Maintenance

The lifespan of a piston accumulator is conditioned according to thecondition of the seal, which is necessary to replace only once the effi-ciency drops, to regain an efficient component at a modest cost. Thiscannot be said for a bladder type, not only for the high cost of thereplacement, also the difficulty in replacing and the need to removethe accumulator from the installation to carry out maintenance.

Main applications3

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3.1 Auxiliary Pressure SourceIn a system that operates with a certain amount of intermittence, thepump is required to intervene for short intervals with significant vol-ume and pressure values. The use of an accumulator as a means ofauxiliary feed, reasonably reduces the size of the required pump, inas much as it is solely used to charge the accumulator duringstopped periods of the system, whist it is the accumulator that pro-vides the higher capacity of oil required by the system during thefunctional period. In this type of application, it can also happen thatthe system requires a quicker response, than an effective availabilityof oil pressure must be available when required. In similar circum-stances, the time lapse between the start up of the pump(Simultaneous to the requirement of pressure) and the instant thatthe system itself reaches the required conditions.

Fig. 2

3.2 Pressure drop CompensatorIn a closed system, where it is absolutely necessary to maintain adetermined pressure value for an indefinite period of time, independ-ent from any fluid feed to any other utility, the presence of an accu-mulator guarantees the required results, eliminating any fluctuationin pressure.

Fig. 3

3.3 Leakage CompensatorDuring the in operational periods of the pump, the accumulatorreplenishes part of the oil in the system, compensating for any leak-ages. This greatly reduces the frequency of interventions to thepump, which is only required to re-charge the accumulator in theevent that the pressure drops below the minimum required value.

Fig. 4

3.4 Circuits with two pressure valuesThis is typical case in presses used for rubber and plastic wherethere is a need for increased speed and moderate pressure duringthe first phase of the stroke, and a slow motion but with high pres-sure in the final stage of the stroke. Whilst the arm of the press isactivated by the high pressure pump, the same motor also activatesthe low pressure pump, which re-charges the accumulator. The dis-charge of this last motion supplies oil for the faster movement at alower pressure, without any assistance from the pump. This decreas-es the size of the installation.

Fig. 5

3.7 Separator of two different fluidsThis is the case where it would be required to transfer the pressurefrom one fluid to another absolutely avoiding direct contact of the twofluids.

Fig. 8

3.8 Hydraulic line shock damperEach time a liquid mass has to vary its velocity an energy equal to thevariation of the quantity of movement of the fluid: Can only be elimi-nated, without consequence, by absorbing it with hydraulic accumula-tors. An important application is used on pipe lines used for refuellingaircraft at major airports or on piping systems at refineries.

Fig. 9

3.9 Pulsation Attenuator and shock absorberThis is a typical application in reciprocating pumps to regulate thestream of liquid in the system. In fact, piston, diaphragm, pneumaticand dosage pumps, produce a pulsating pressure in the hydraulic cir-cuit, which in the long term, can effect the good operation and longevi-ty of the components. The installation of a piston accumulator on thesuction line and in close proximity to the pump, will reduce ox illationsto within acceptable values.

Fig. 10

Main applications3

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3.5 Compensation ElementsPressure – Volume

The presence of an accumulator tends to eliminate any dangerderived from uneventful increase in pressure in the system, be itthrough thermal effect, as a consequence of piston movement or anyother possible cause. In the case of an hydraulic control system of aroll mill for example, the instant that the ingot is fed into the rolls, asuper-pressure in the hydraulic system is created. This has to beabsorbed by a battery of accumulators if it is to avoid any variation inthe force of the cylinder or any other harmful consequence, be it to thesystem or the product.

Fig. 6

3.6 Emergency SourceA sudden breakdown in the system could incapacitate the hydrauliccircuit to any intervention, as a result of a pressure drop. Only usingone or more accumulators, or even better, a battery (accumulators +additional bottles could at least guarantee one emergency operation)consenting for example the intervention of protection and securitydevices. This is very important in the case of the control of the regu-lation rods in nuclear reactors or the directional system or braking sys-tem in heavy vehicles. In these cases the dimensioning of the accu-mulator or battery, should be made by valuating the volume of liquidnecessary in relation to the number of emergency manoeuvresrequired.

Fig. 7

4.1 Project DataWhen sizing a piston accumulator, independently from the application,it is necessary to precisely define the following operational parame-ters.

• Minimum working pressure P1

In the minimum pressure at which the system will still function.

• Maximum working pressure P2

To the maximum pressure at which the system will function. Thevalue of P2 must always be less than or equal to the maximum work-ing pressure of the accumulator.

• Volume ∆VIs the volume accumulate or restored∆V = V1 – V2

where V1 (Volume of gas at P1)V2 (Volume of gas at P2)

• Minimum temperature of gas T1

Is the minimum working temperature the gas.

• Maximum temperature of gas T2

Is the maximum temperature the gas.

• Mode and /or field of implementation ADIABATIC or ISOTHER-MIC transformation

The compression and decompression of nitrogen contained in theaccumulator is regulated by the prefect gas laws. If the compressionor the decompression is slow (in excess of 3 minutes) such to allowthe gas to maintain the temperature close to constant, you will haveISOTHERMIC transformation (Pressure stabilizer, forces balancer,volume compensator, feed in the lubrication circuits) in as much as thechange of gas volume follows the law of Bayle Mariotte.

V1 x P1 = V2 x P2

In other cases (energy reserve, pulsation compensator, water hammerabsorbers etc.) the heat exchange with the ambient is negligible giventhe speed with which it operates. You therefore have contemporarypressure and temperature variations of the gas, with which you haveADIABATIC transformation, governed by the law:

V1n x P1 = V2n X P2

Where the coefficient n takes on values from 1 to 1.4 during theprocess of compression or decompression (See fig. 11 and fig. 13).

Fig. 11

Accumulator Sizing4

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4.2 Pre-charge pressure PoThe definition of the pre-charge pressure of the accumulator has afundamental importance in order to obtain maximum efficiency in con-ditions that do not prejudice the longevity of its components. The max-imum accumulate or replenishment of liquid we have in theory, with apre-charge Po equal to the minimum pressure of exertion P1. In prac-tice the pre-charge pressure (at the maximum exertion pressure T2)should be at least less than 3 ÷ 5 bar of the minimum pressure ofexertion, to avoid that the piston strike, the oil side flange and dam-age the components during replenishment of fluid.It is advisable that the minimum pre-charge pressure (At the minimumexertion pressure T1) be in excess of friction force and also the weightof the piston itself in a case of horizontal installation or the fluid sidein the upright position.For specific requirements consult our Technical Service Dept. Forparticular applications, and in the following cases, the recommendedpre-charge values are:

PO = 0,95 ÷ 0,97 P1

The value of PO is referred to the maximum working temperature ofthe gas, foreseen by the user.

The pre-charge and the control are usually affected at a different tem-perature that the maximum working temperature T2, in which the pre-charge pressure PO at a pre-charge or control Tc becomes:

293 + TC (ºC)Po pre-charge/control = PO x

273 + 12 (ºC)

Example for a pre-charge effectuated at 20º C:

293PO at 20ºC = PO x

273 +T2 (ºC)

N.B. The pre-charge pressure of EPE accumulators supplied direct-ly from the factory, are referred to a temperature of 20º C.

Pulsation compensator and shock absorber:

PO = 0,6 ÷ 0,75 Pm or PO = 0,8 P1

Where:

Pm = medium working pressure

Hydraulic line shock damper:

PO = 0,6 ÷ 0,9 Pm

Where:

Pm = medium working pressure of free flow.

∆V

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Accumulator sizing4

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4.3 Calculation principlesCompression and expansion of gas inside the accumulator takesplace according to the Boyle-Mariotte law regarding the statuschange in the perfect gases:

Po · Von = P1 · V1n = P2 · V2n

The PV diagram Fig. 12 shows the “pressure-volume” relationshipinside the accumulator.

where:

VO = Nitrogen pre-charge volume at pressure PO (litres).It is the maximum volume of gas which can be stored in theaccumulator.

V1 = Nitrogen volume at pressure P1 (litres).

V2 = Nitrogen volume at pressure P2 (litres).

∆V = Volume of discharged or stored liquid (litres).

PO = Precharge pressure (bar).

P1 = Minimum operating pressure (bar).

P2 = Maximum operating pressure (bar).

n = Polytropic exponent.

The curve of volume variation as a function of pressure is depen-dant on the exponent n, which for nitrogen is contained betweenthe limit values:

n = 1 In case compression or expansion of nitrogen takes placeso slowly that a complete intercharge of heat is allowedbetween gas and enviroment, that is at constanttemperature, the condition is isothermal.

n = 1,4 When operation is so quick that no interchange of heatcan take place, the condition is adiabatic.

In fact, these are theoretical and not practical conditions.It is however possible to state, with reasonable accuracy, that whenan accumulator is used as a volume compensator, leakagecompensator, the condition is isothermal. In the remainingapplications, such as energy accumulator, pulsation damper,emergency power source, dynamic pressure compensator, waterhammer absorber, shock absorber, hydraulic spring, etc., it ispossible to state, with reasonable accuracy, that the condition isadiabatic.

,When is required a more accurate calculation, is possible to useintermediate values of n as function of t, that is of expansion orcompression time, according to diagram (fig. 13):

Note: In all calculations, pressures are expressed as absolute bar(pressure of a fluid or a gas refer to the void) and Temperature asKelvin degrees (°K=273 + °C).

4.4 Volume calculation(isothermal condition)

When n = 1, the Boyle-Mariotte law becomes

The difference between volume V1 (at minimum operatingpressure) and V2 (at maximum operating pressure) gives theamount of stored liquid (See Section 1.1):

which shows that accumulator volume increases when ∆V isincreasing, when PO is decreasing and when the difference betweenthe two operation pressures P1 and P2 is decreasing.The values of ∆V and VO could be deduced more quickly from thediagrams on pages 12 and 13.

9

Accumulator sizing4

4.4.1 Volume compensator (isothermal)A typical example of calculation in the isothermal condition is whenthe accumulator is used as a volume compensator.

Assume a tube with ØI.D.=77,7 mm, 120 m long and inside whichsome oil is flowing at a pressure of 30 bar and a temperature ofΤ1 = 10°C and Τ2 = 45°C.Permissible change of pressure ± 8%.

The volume variaton will be:

P1 = 8% of 30 = 27.6 bar 28.6 (absolute pressure)P2 = 8% of 30 = 32.4 bar 33.4 (absolute pressure)PO = 0.95 · 27.6 = 26.2 bar 27.2 (absolute pressure)

27 2728.6 33.4

Problem solution requires the use of an accumulator stationwith 3 accumulators type AP50P250...

or: 1 accumulator and 2 additional bottles 50 litres.2 accumulators from 80 litres1 accumalator from 150 litres

4.4.2 Leakage compensator (isothermal)a) Assume a molding press working at 200 bar which has to be kept

closed during the curing time and at constant pressure. Min. per-missible pressure 198 bar.After the mold has been closed, the pump is stopped.The oil leakages are in the order of 2 cm3/minute.Curing time is 60 minutes.

12.8 litres

The capacity of the standard accumulator closest to the calculatedvalue is 15 litres. So the chosen accumulator is AP15P375...

,b) If it is required to know when the pump must operate again to

reload an accumulator of 15 litres to maintain the conditionstated on a), we will have:

4.5 Volume calculation(adiabatic condition)

Starting from the basic formula:

Formulas are valid when operation is taking place in adiabatic condi-tions both in the expansion as well as the compression phases.

Bear in mind however that accumulator yield, and therefore theaccumulator calculation, is influenced by both operating temperatureand pressure (see section 4.6 and 4.7).

∆V = Ql · t = 0.002 x 60 = 0.12 It.

P1 = 198 bar 199 (absolute bar)

P2 = 200 bar 201 (absolute bar)

PO = 0.95 · 198 = 188 bar 189 (absolute bar)

Accumulator Sizing4

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4.6 Temperature influenceIt should be anticipated that the operating temperature will changeconsiderably during the cycle and this variation should be taken intoaccount when the volume is calculated.

If an accumulator is sized to a maximum temperature, then theprecharge pressure will be referenced to that temperature. Whenthe temperature drops there will be a comparable reduction of theprecharge pressure according to the Gay Lussac law on therelationship between pressures and volumes, as a result, you willget a lower accumulator capacity.

Therefore it will be necessary to have a higher VO to accumulate orto yield the same amount of liquid ∆V (see section 4.4).

The relationship between pressures and volumes is:

VOT = VOT2

T1

where:

T2 = (°C)+273 = max. working temperature (°K).

T1 = (°C)+273 = min. working temperature (°K).

VO = volume calculated neglecting thermal variation (litres)

VoT = increased volume for thermal variation (litres)

Example:Assume the accumulator volume has to be calculated with the fol-lowing data:

Stored volume ∆V = 1.7 Lt. in 2 s

Min. pressure P1 = 50 bar 51 absolute bar

Max. pressure P2 = 115 bar 116 absolute bar

Operating temperature = +25°C ÷ +70°C

The precharge pressure referred to maximal temperature is:

PO = 0.95 P1 = 47 bar 48 absolute bar

Volume, calculated in adiabatic conditions, will be:

4.7 Correction coefficent for high pressureThe formulas refer to ideal gases, but industrial nitrogen used in accumulators does not behave according to ideal gas laws when pressuresincrease.It is convenient to keep in mind this characteristic for pressure P2 > 200 bar, both for adiabatic as well as for isothermal conditions.

where:

Vor = real volume of accumulator to be used foroperating pressures P1 and P2.

∆Vr = real yield obtained from accumulator forthe same pressures.

Ci, Ca = Coefficients to be deduced from diagramsof Figures 14 and 15.

Accumulator sizing4

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4.8 Emergency energy reserveTypical occasion when storage is slow (isothermal) and dis-charge is quick (adiabatic).

Volume will be given by:

where:

n = 1.4 adiabatic coefficient (quick discharge phase)

n = 1 ÷ 1.4 polytropic coefficient (slow storage phase)

Value is a function of time and it will be deduced from the diagramin Fig. 13.

In the majority of cases it is possible to suppose nc = 1 so thatcalculation is simplified and result is not affected:

Example:

An accumulator must discharge 4.6 litres of oil in 3 seconds with achange of pressure from P2 = 280 bar to P1 = 208 bar.The loading time is 4 minutes. Define the capacity keeping in mindthat ambient temperature will change from 20°C to 50°C.

Considering the correction coefficient for high pressure and thetemperature change, we have:

4.9 Pulsation compensator QA typical calculation in adiabatic conditions due to high speedstorage and discharge.The liquid amount ∆V to be considered in the calculation is afunction of type and capacity of pump:

Volume becomes:

Pump type K1 piston, single acting 0.691 piston, double acting 0.292 pistons, single acting 0.292 pistons, double acting 0.173 pistons, single acting 0.123 pistons, double acting 0.074 pistons, single acting 0.134 pistons, double acting 0.075 pistons, single acting 0.075 pistons, double acting 0.0236 pistons, double acting 0.077 pistons, double acting 0.023

Example:Assume a 3-piston pump, single acting, with a flow rate Q = 8 m3/hand operating pressure of 20 bar. Calculate the volume necessary tolimit the remaining pulsation to α = ± 0,25%. Pump R.P.M. 1480Working temperature 40°C.

The most suitable accumulators is the low pressure type: AP1,5P375...

and stored volume by:

Accumulator sizing4

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4.10 Hydraulic line shock damperA rapid increase in pressure caused by a high acceleration ordeceleration in flow is commonly known as water hammer.The overpressure, ∆P max, that takes place in piping when a valveis closed is influenced by the lenght of the piping, the flow rate,the density of the liquid and the valve shut down time.This is given by:

The volume of the accumulator required to reduce shock pressurewithin predetermined limits AP, is obtained with:

Example:

Assume a water pipe ( = 1000 Kg/m3) with internal diameterd = 80 mm, lenght L = 450 m, flow rate Q = 17 m3/h, operatingpressure P1 = 15 bar, allowable overpressure ∆P = 2 bar, valveclosure time t = 0.8 s.

An accumulator of 120 litres, type AP120P250....

4.11 Accumulator +additional gas bottles (transfer)

In all cases where a considerable amount of liquid must beobtained with a small difference between P1 and P2, the resul-tant volume VO is large compared to ∆V.In these cases it could be convenient to get the required nitrogenvolume by additional bottles.Volume calculation is performed, in function of the application, both inisothermal as well as in adiabatic conditions using the formulasgiven before always taking temperaure into account.To get the maximum of efficiency it is convenient to fix for prechargequite a high value. In cases of energy reserve, volume compen-sator, hydraulic line shock damper, etc. it is possible to use:

PO = 0.97 P1

Once the required gas volume is calculated, the volume must beallocated between the minimum indispensable portion VA, which willbe contained in the accumulator, and the remaing portion VB, whichrepresents the volume of additional bottles.

That means that the sum of volume of required liquid plus volumechange due to temperature must be lower than 3/4 of accumulatorcapacity.The bottle volume is given by the difference

Example:

Suppose a ∆V = 30 Its. must be obtained in 2 seconds going from apressure P2 = 180 bar to P1 = 160 bar.Temperatures: θ1 = 20°C; θ2 = 45°C

One accumulators AP100P250.... are used with total VO = 100 Its. plus 6bottles of 50 Its. type BB52P360...

5.1 Technical CharacteristicsWorking pressures PS: up to 375 bar (others on request)

Test pressures PT: 1,43 x PS

Minimum working temperature: -20 °C

Maximum working temperature: +120 °C (150 °C on request)

Nominal capacity: up to 300 litres

Bores: 60,100,180,250,350

Accumulator selection5

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5.2 Materials

Accumulator Body: Low carbon steel, EN 10216-3TC type P335N,seamless tube, internally lapped with a maximum roughness of Ra0,2. Stainless steel AISI 316L on request.Gas side end cap: Low carbon steel. Stainless steel on request.Oil side end cap: Low carbon steel. Stainless steel on request.Piston: Aluminum EN AW-2011For protective coating consult our Technical Service.Gasket: Standard P (Perbunan- NBR)

On request V (Viton or other compounds)Anti-extrusion and guide rings: PTFEGas Valve: Low carbon steel with 5/8 UNF fitting and coated in whitezinc chromate.

5.3 Tests and Certification

– CE (PED) the accumulators serried AP are designed and homolo-gated to use group 2 fluids (Not hazardous) in conformance withEUROPEAN DIRECTIVE 97/23/EC.To use group 1 fluids consult our technical service.The accumulators are pressure vessels and as such are subjectto national government regulations in ever country they areinstalled.For all the European Countries, design, construction and accumu-lator test must be done according to the Directive of pressureequipment 97/23/EC.EPE ITALIANA, also in virtue of quality system used EN ISO9001:2000, works according to modules H and H1 of total qualityguarantee and design control issued by the Notify Body. The abovementioned directive includes the pressure equipment that exceed0,5 bar. So all the accumulators are involved in this directive eventhough it provides different procedures of test and certification.Concerning this, keep in mind that accumulators up to 1 litre volu-me included, even if it is manufactured according to the Directive97/23/EC, are not marked EC and are not provided with the confor-mity declaration.For volumes higher than 1 litre each accumulator after the test ismarked with the mark CE followed by the number that identify theNotify Body.For these accumulators, both high pressure and low pressure,the documentation necessary includes the conformity declarationand the manual’s operator.

– ATEX. EPE ITALIANA can supply the series of accumulators inaccordance to directive ATEX 94/9/CE (attachment VIII) and to theharmonized norm EN, 13463-1, relative to not electric equipmentfor uses in environment with atmosphere potentially explosive thatare included into the classification ATEX CE 12GcT4.

As well EPE ITALIANA provides other tests and certification for coun-tries in which the CE norm is not accepted:

– GOST -R for Russia– ML (ex SQL) for China– RINA for use on ships– BS-L Lloyds register for construction of ships– ASME for the United States, Canada, South Africa etc.

– For other countries in which specific test are not required, theaccumulator are however always manufactured according to theEuropean norm, but supplied without CE markings and with a fac-tory test certificate.

Relative documentation is supplied in an envelope attached to thegoods.

The strict EPE quality standard and relative test, guarantee a safeoperation of these accumulators (the operator must thoroughly famil-iarize himself with the operational and maintenance manual). Theaccumulators are pressure vessels and must be tested to the nation-al government regulations in every country they are installed.

5.4 VelocityThe range of EPE accumulators allows to choose 2 diameter bores forthe same capacity, the choice, as well as being economic, it is influ-enced by available installation space and the amount of oil required inoperation of the time cycle. In fact, it is necessary to ensure that thepiston velocity does not exceed 2 meters for second. For higherspeeds consult our Technical Service.Even the fluid flow must be chosen in relation to the acceptable loses,however the velocity of the fluid is not to exceed 10m for second.In the case where piston accumulator is connected to additional bot-tles, the tubing and connectors are to be chosen so as not to allow thegas flow at a velocity in excess of 30m for second.

5.5 FiltrationAs with al oleodynamic components, even the accumulators, to guar-antee a longer working life, it is necessary that the fluid under pres-sure does not contain contaminants such as metal particles, wateretc. As much as the fluid may be pure it must conform to ISO4406norm and the quality of the filters must conform to appropriate ISOstandard. The grade of filtration is dependent on the components ofthe system and the application. The minimum grade request forhydraulic systems is equivalent to class 19/15, ISO 4406 which is 25micron with B≥75 ISO 4572.

5.6 Pre-chargeThe EPE accumulators with the gas side connectors complete withpre-charge valve (V), if not otherwise requested during ordering, aresupplied with a pre-charge of nitrogen at 30 bar.

CAUTION: Use only nitrogen NOT oxygen or compressed air(Danger of explosion)

Series

Capacity

Gasket material

Maximum working pressure

Body and flange materials

Nominal internal diameter

Type of connection side

Dimension of connection sideType of connection gas side

Dimension of connections gas side

Piston accumulator = AP

Nominal capacity in litres fluid side:diam. 60 = 0.1 - 0.25 - 0.8 - 1diam. 100 = 1-1.5-2-2.5-3-4-5-6-8-10diam. 180 = 6-8-10-15-20-25-30-40-50-60-80diam. 250 = 30-40-50-60-80-100-120-150-180diam. 350 = 100-120-150-180-200-250-300Other capacity on request.

Gasket materials: Perbunan = P Viton = VPerbunan, elastomer in nitryl rubber nitrilica suitablefor working temperatures of –20÷+80 °C andpetroleum based fluid, mineral oil, lubrificants,diesel oil, etc.Viton, eleasometer suitable for temperatures –20÷+120 °C and fluidsat high temperatures or synthetic.Other compounds and temperature on request.

Maximum working pressure in bar:diam. 60 = 375diam. 100 = 375diam. 180 = 250 – 375diam. 250 = 250 – 350diam. 350 = 220 – 350The pressure is limited to 210 bar in cases where connctiontype L is chosen (flange SAE 3000).Other pressures on request.

Carbon steel whit a coat of rust inhibitor = CCarbon steel chemicallynickel pladed th. 25µ = NStainless stell AISI 316–L = XOther materials and treatment on request.

Internal diameter in mm = 60 – 100 – 180 – 250 – 350

Without connection = OFemale thread ISO 228 = G (standard)Female thread NPT F = PFemale thread ISO 228 whit chamfer for or = AHoles for flange SAE 3000, metric screew = LHoles for flange SAE 6000, metric screew = HHoles for flange ANSI, metric screew = BHoles for flange UNI = UHoles for flange for special flange = FFemale thread metric = MFemale thread SAE = SOther connections on request.

For the type of connection: 0 = 0

G – P – A – L – H : 1/8” = 11/4” = 23/8 = 3

1/2” = 4 (*)3/4” = 5

1” = 6 (**)1”1/4 = 71”1/2 = 8 (***)

2” = 92”1/2 = 10

* (standard for int. diam. 60) ** (standard for int. diam. 100)*** (standard for int. diam. 180–250–350)

B = To be specify DIMENSION / RATING Es. 1” ANSI300 = 1/300U = To be specify the DN / PV Es. DN50 PN16 = 50/16F = – To be specify diameter cental hole, number, dimension and depth of fixing holes, wheel center and reces of or

M = To be specify the DIAMETER / PITCH Es. M18x1,5 = 18/1,5

S = To be specify the DIAMETER in”-PITCH in” Es. (SAE6) 9/16–18 = 9/16-18

Standard pre–charge valve whit 5/8 UNF tread = V (standard)Standard pre–charge valve whit 5/8 UNF tread in stainless steel = VXWithout connection = OFemale thread ISO 228 = GFemale thread NPT F = PFemale thread ISO 2228 whit camfer for OR = AHoles for flange SAE 3000, metric screew = LHoles for flange SAE 6000, metric screew = HHoles for flange ANSI, metric screew = BHoles for flange UNI = UHoles fby design for special flange = FFemale thread metric = MFemale thread SAE = SOther connections or pre–charge valves on request.

V = – (Standard pre–charge valve whit 5/8 UNF tread) VX = –For the type of connection: � = 0

G – P – A – L – H : 1/8” = 11/4” = 2 (standard for diam. int. 60)3/8” = 31/2” = 43/4” = 5

1” = 6 (standard for diam. int. 100)1”1/4 = 71”1/2 = 8 (standard for diam. int. 180–250–350)

2” = 92”1/2 = 10

B = To be specify DIMENSION / RATING Es. 1” ANSI 300 = 1/300

U = To be specify the DN / PN Es. DN50 PN16 = 50/16

F = – To be specify diameter cental hole, number, dimension and depth of fixing holes, wheel center and reces of OR

M = To be specify the DIAMATER/PITCH Es. M18x1,5 = 18/1,5

S = To be specify the DIAMETER “inch”/PITCH “inch” Es. (SAE6) 9/16–18 = 9/16–18

– –

Test and certificationFactory testing = 0GOST– R = 1ML (ex SQL) = 3RINA = 4BS–LLOYS’S REGISTERR = 5GERMANISCHER LLOYYD = 6ASME = 7PED (97/23/CE) = 8ATEX (94/9/CE) = 9Other to be specified = 10

In the case of more certification to be indicatethe request type spacing of /Es. certification PED + ATEX = 8/9

Variant and/or accessoriesElectric control of position of piston(last 300 mm gas side = C.....add n° of magnetic switch. Es. n° 2 magnetic switch = C2Electric control of position of piston(last 700 mm gas side = D.....add n° of magnetic switch. Es. n° 2 magnetic switch = D2Transducer of position potentiometric = TPTransducer of position whit out 0–10 V = T10Transducer of position whit out 4–20 mA = T20Exit roadwhit indicator = U ....add of n° of micro switch. Es. n° 3 micro switch = U3Piston in alluminium anodized = P1Piston in carbon steel = P2Piston in stainless steel = PXPiston iwhit seal low friction = PBSpecial accumulator by design = A .....add of n° of design.

AP 10 P 375 C 100 G 4 V 8 ......

Accumulator selection5

14

5.7 Order code

Dimension and components5 6

15

6.1 Dimension

98311881388159319982408281834284038155217622072238225923112363215921802

211224222632

31523672

Dimension and components6

16

6.2 Spare parts

6.3 Order code

Accumulator station7

17

7.1 Technical Characteristics

Batteries of accumulators are used when the capacity or volumesrequired are in excess of the capacity of one available accumulator inour range or when the pressure values P1 and P2 are relatively closewhen a large volume in respect to ∆V, is required.In this last case it would be more convenient achieving the volume ofnitrogen by using additional bottles of nitrogen, connected to thedefined accumulator.EPE is in a position to supply batteries of any dimensions, in executionwith standard accumulators, or else with piston accumulators connect-ed to nitrogen cylinders, complete with valves and/or safety devices.

7.2 Constructive Characteristics

EPE Technical Services are capable to fulfill any request, proposingcompetitive solutions validated with calculation programs and avant-garde simulations.

7.3 Designations

BA 2/4 P 300 A 1544

7.4 Example

Fig. 16

Fig. 17

accumulatorstation = BA

Number of accumulatorsNumber of additionalbottles = 2/4

DrawingNumbers = A...

Total volume Vo accumulator+ bottles in litres = 300

Pistonaccumulators = P

18

Additional Bottles8

8.1 Version BBType forged steel with two heads.

8.1.1 GeneralCylinders manufactured in forged steel, concur additional nitrogencylinders for piston/pocket accumulators. Version BB is only manufac-tured with a capacity of 52 litres and with certification CE. The exter-nal surface is sandblasted and painted with a coat of epoxypolyamides RAL8012. Upon request the cylinders BB, can be sup-plied with nickel platting on the external surface.

8.1.2 Technical CharacteristicsWorking pressure PS : 360 barTest pressure PT : 515 barMinimum working temperature : - 40 °CMaximum working temperature : + 120 °CNominal capacity: 52 litres

8.1.3 Order code

8.1.4 Dimension

8.2 Version ABType accumulator without the pistons and the workmanship to theinside.

8.2.1 GeneralWhen the pressure difference between the maximum and minimum isrelatively small and the quality is of replenishment, fluid is reasonablybig; an accumulator of big dimensions is needed.

For this reason we recommend the use of piston accumulators con-nected to additional nitrogen bottles in order to re-dimension thecapacity of the accumulator. For calculations be it of the accumulatoror total volume require, our Technical service with dedicated software.

8.2.2 Technical CharacteristicsWorking pressure PS: Up to 375 bar (others on request)Test Pressure Pt: 1,43 X PSMinimum Working Temperature: -20 ºCMaximum Working Temperature: +120 ºCNominal capacity: Up to 300 LitresNominal Diameters: 60,180,18,250,350

8.2.3 MaterialsBody: Low carbon steel EN 10216/3TC type P335N with epoxypolyamides RAL 8012 primer.Stainless steel AISI 316-L on request.End caps: Low carbon steel.

AISI 316-L on request.Gasket: Standard P (Perbunan – NBR)

On request: V (Viton) or other compounds

8.2.4 Tests and certification

– CE (PED) the bottles serried AP are designed and homologated touse group 2 fluids (Not hazardous) in conformance with EURO-PEAN DIRECTIVE 97/23/EC.To use group 1 fluids consult our technical service.The bottles are pressure vessels and as such are subjectto national government regulations in ever country they areinstalled.For all the European Countries, design, construction and bottletest must be done according to the Directive of pressure equip-ment 97/23/EC.EPE ITALIANA, also in virtue of quality system used EN ISO9001:2000, works according to modules H and H1 of total qualityguarantee and design control issued by the Notify Body.The abovementioned directive includes the pressure equipment that exceed0,5 bar. So all the bottles are involved in this directive even thoughit provides different procedures of test and certification.Concerning this, keep in mind that accumulators up to 1 litrevolume included, even if it is manufactured according to theDirective 97/23/EC, are not marked EC and are not provided withthe conformity declaration.For volumes higher than 1 litre each bottle after the test ismarked with the mark CE followed by the number that identify theNotify Body.For these bottles, both high pressure and low pressure,the documentation necessary includes the conformity declarationand the manual’s operator.

– ATEX. EPE ITALIANA can supply the series of bottles in accor-dance to directive ATEX 94/9/CE (attachment VIII) and to the har-monized norm EN, 13463-1, relative to not electric equipment foruses in environment with atmosphere potentially explosive that areincluded into the classification ATEX CE 12GcT4.

As well EPE ITALIANA provides other tests and certification for coun-tries in which the CE norm is not accepted:

– GOST -R for Russia– ML (ex SQL) for China– RINA for use on ships– BS-L Lloyds register for construction of ships– ASME for the United States, Canada, South Africa etc.

– For other countries in which specific test are not required, the bot-tle are however always manufactured according to the Europeannorm, but supplied without CE markings and with a factory testcertificate.

Relative documentation is supplied in an envelope attached to thegoods.

The strict EPE quality standard and relative test, guarantee a safeoperation of these bottles (the operator must thoroughly familiarizehimself with the operational and maintenance manual). The bottlesare pressure vessels and must be tested to the national governmentregulations in every country they are installed.

G2 = 1 1/2” BSP

R0 = Blind adapter

R1 = adapter 1/2 BSP

C = Carbon steel whit a coat of rustinibitor

N = Alloyed steel with nichet-plating on the outside only (25 µm)

V = Alloyed steel with spercial esternal painting

– = like bottle

N = 25 µm nikel-plated

X = stainless steel

0=factory testing

1=GOST-R

3=ML (ex SQL)

4=RINA

5=BS-LLOYD’S REGISTER

6 =GERMANISCHER LLOYD

7 =ASME

8 =PED (97/23/CE)

9 =ATEX (94/9/CE)

10=Other to be specified

52

Additional Bottles8

19

Series

Capacity

Gasket materials

Maximum working pressure

Body and flange materials

Nominal internal diameter

Type of connection side AType of connection side B

Dimension of connections side B

Test and certification

AB 10 P 375 C 100 G 4 G 4 8

Additional bottle - AB

Nominal capacity in litres fluid side:diam. 60 = 0.1 - 0.25 - 0.8 - 1diam. 100 = 1-1.5-2-2.5-3-4-5-6-8-10diam. 180 = 6-8-10-15-20-25-30-40-50-60-80diam. 250 = 30-40-50-60-80-100-120-150-180diam. 350 = 100-120-150-180-200-250-300Other capacity on request.

Gasket materials: Perbunan = P Viton = VPerbunan, elastomer in nitryl rubber nitrilica suitablefor working temperatures of –20÷+80 °C andpetroleum based fluid, mineral oil, lubrificants,diesel oil, etc.Viton, eleasometer suitable for temperatures –20÷+120 °C and fluidsat high temperatures or synthetic.Other compounds on request.

Maximum working pressure in bar:diam. 60 = 375diam. 100 = 375diam. 180 = 250 – 375diam. 250 = 250 – 350diam. 350 = 220 – 350The pressure is limited to 210 bar in cases where connctiontype L is chosen (flange SAE 3000).Other pressures on request.

Carbon steel whit a coat of rust inhibitor = CCarbon steel chemicallynickel pladed th. 25µ = NStainless stell AISI 316–L = XOther materials and treatment on request.

Internal diameter in mm = 60 – 100 – 180 – 250 – 350

Without connection = OFemale thread ISO 228 = G (standard)Female thread NPT F = PFemale thread ISO 228 whit chamfer for or = AHoles for flange SAE 3000, metric screew = LHoles for flange SAE 6000, metric screew = HHoles for flange ANSI, metric screew = BHoles for flange UNI = UHoles for flange for special flange = FFemale thread metric = MFemale thread SAE = SOther connections on request.

For the type of connection: 0 = 0

G – P – A – L – H :1/8” = 11/4” = 23/8 = 3

1/2” = 4 (*)3/4” = 5

1” = 6 (**)1”1/4 = 71”1/2 = 8 (***)

2” = 92”1/2 = 10

* (standard for int. diam. 60) ** (standard for int. diam. 100)*** (standard for int. diam. 180–250–350)

B = To be specify DIMENSION / RATING Es. 1” ANSI300 = 1/300U = To be specify the DN / PV Es. DN50 PN16 = 50/16F = – To be specify diameter cental hole, number, dimension and depth of fixing holes, wheel center and reces of or

M = To be specify the DIAMETER / PITCH Es. M18x1,5 = 18/1,5

S = To be specify the DIAMETER in”-PITCH in” Es. (SAE6) 9/16–18 = 9/16-18

Without connection = OFemale thread ISO 228 = GFemale thread NPT F = PFemale thread ISO 2228 whit camfer for OR = AHoles for flange SAE 3000, metric screew = LHoles for flange SAE 6000, metric screew HHoles for flange ANSI, metric screew = BHoles for flange UNI = UHoles fby design for special flange = FFemale thread metric = MFemale thread SAE = SOther connections or pre–charge valves on request.

For the type of connection: � = 0

G – P – A – L – H : 1/8” = 11/4” = 23/8” = 31/2” = 4 (standard for diam. int. 60)3/4” = 5

1” = 6 (standard for diam. int. 100)1”1/4 = 71”1/2 = 8 (standard for diam. int. 180–250–350)

2” = 92”1/2 = 10

B = To be specify DIMENSION / RATING Es. 1” ANSI 300 = 1/300

U = To be specify the DN / PN Es. DN50 PN16 = 50/16

F = – To be specify diameter cental hole, number, dimension and depth of fixing holes, wheel center and reces of OR

M = To be specify the DIAMATER/PITCH Es. M18x1,5 = 18/1,5

S = To be specify the DIAMETER “inch”/PITCH “inch” Es. (SAE6) 9/16–18 = 9/16–18

Factory testing = 0GOST– R = 1ML (ex SQL) = 3RINA =4BS–LLOYS’S REGISTERR = 5GERMANISCHER LLOYYD = 6ASME = 7PED (97/23/CE) = 8ATEX (94/9/CE) = 9Other to be specified = 10

In the case of more certification to be indicatethe request type spacing of /Es. certification PED + ATEX = 8/9

–

Dimension of connection side A

8.2.5 Order code

Additional bottles8

20

8.2.6 Dimension

21

Elements of clamping and sleeve9

9.1 GeneralThe clamping of piston accumulators must be done in such a way notto induce external forces on the body or the mountings of the accu-mulator. Especially for horizontal assemblies, and for heavier types,it is necessary to use securing devices that support the accumulatorand avoid dangerous vibrations.

9.2 Constructive characteristicsThe mounting “U” bolts for piston accumulators are manufacturedfrom zinc coated carbon steel and re complete with 2 nuts and zinccoated flat washers. Upon request they can be supplied in stainlesssteel.

9.3 Dimensions and order code

U-Bolt clamps Plastic pipesaddles

Fig. 18

9.5 Assembly equipment.The sleeve equipment to re-assemble the piston accumulators is nec-essary every time an accumulator needs to be stripped for mainte-nance (For example, when replacing piston seals) and then re-fittingthe piston to the accumulator.

9.6 Order code

Fig. 19

External diameter

130

210220

292312

405419

Ordercode

1154511549115461155011547115511154811552

fig.

ABABABAB

A

16475

248140352220452220

D

13370

21975

31675

41975

H

1238

1768

2298

2878

H1

21726

31126

41832

52632

H2

10510

12510

12510

14510

I

14840

22890

332150428150

N

M 1615

M 2025

M 2030

M 2430

Nominal internaldiameter

of the piston

60

100

180

250

350

Sleeve ordercode

11555

11556

11557

11558

11559

Pre-loading and checking set10

22

10.1 GeneralIt is used for the periodic check of accumulator pre-charge and for the inflation of accu-mulators themselves after the replacement of the bladder or it is used for the chan-ge of pre-change value. For the inflation is necessary a connection to a bottlefilled with industrial dry nitrogen with a pressure higher than the precharge valuerequired, provided with pressure reducer (mandatory, for safety reasons, during theinflation of accumulators with PS < 210 bar).Furthermore the use of a pressure reducer make easier the slow and graduatedinflow of nitrogen on the bladder avoiding in this way the possibility of damaging ofthe bladder itself.

10.2 ConstructionSTANDARD VERSION includes:

• Valve body complete with ring nut connection to accumulator gas valve, pressuregauge, bleed and non return snap-in hose connection.

• 3 m charging hose for high pressure series complete with bottle connections.• One connection nipple to pressure reducer.• Set of spare gaskets.• Case.

ON REQUEST:

• ADAPTER for special accumulator gas valves.• CHARGING HOSE with lenght of 6 m.

10.3 Technical features

Max working pressure: 600 bar

Accumul. connection: 5/8" UNF (standard)7/8” UNF; ø 7,7x1/32” (Vg8); 1/4” ISO 228; (on request)

Bottle connection: See designation (ch 10.5), drawings and table ch. 10.7page 35

Pressure gauges: - Ø 63 connection 1/4” ISO 228- Full scale 250 bar for high pressure accumulators- Full scale 25 bar for low pressure accumulators

Weight: 1,8 kg (case included)

10.4 Spare parts

Gasket set 2160 Complete bleed 2164

Non-return valve 2162 Charging hose 2166/

Central pin 2165 Pressure gauge 2163/

10.5 Identification codeThe example below shows equipment for filling and checking with pressure gaugeof 250 bar, with accumlulator connection 5/8" UNF and standard bottle connection,complete with 3 m hose and case.SAMPLE OF DESIGNATION:

(metres)...(bar)...

PC 250 S 1 – –

Type Pressuregauge (bar)

Connection toaccumulator

Connection to bottle 1)

(according to Country standards)Charging hose

(metres)

4 = ArgentinaAustraliaGreat BriitainGreeceIndiaIndonesiaNew ZelandPhilippinesPortugalSingaporeTurkey

5 = BrazilSouth America

6 = South Africa7 = Canada

USA8 = Russia

Venezuela9 = Japan

10 = Taiwan11 = China12 = Korea

– = 3 m(standard)

L = 6 m(on request)

PC

Pre-loadingand checking

25

250

S = 5/8" UNF (standard)

A = ø 7,7x1/32” (Vg8)(adapter 50019)

B = 7/8” UNF(adapter 10143)

C = 1/4" ISO 228(adapter 50510)

D = ø 7,7x1/32” (Vg8)(long thread)(adapter 50508)

1 = Italy2 = Austria

Czech RepublicDenmarkFinlandGermanyNetherlandsNorwayPolandSwedenSwitzerland

3 = BelgiumEgyptFranceHungaryMexicoMoroccoRomaniaSaudi ArabiaSloveniaSpainTunisia

Subject to change

1) Other types on request

23

Pre-loading and checking set10

Subject to change

The use of pre-loading set for the inflationof accumulators “low pressure” seriesrequires, for safety reasons, the use of a pressure reducer mounted on thenitrogen bottle calibrated at a pressureequal or lower than the max working pressu-re PS marked on the accumulator body.The connection nipple between charginghose and reducer it is showed by the sideof the page and it is normally suppliedwith the pre-laoding set.

10.7 Connection charging hose - additional bottleFor “high pressure” accumulators and, in general, for all the types with PS ≥210bar, it is possible to connect the nitrogen bottle through the proper nipplewithout the use of pressure reducer.The proper nipple has to be chosen according to the origin Country of nitrogenbottle, as showed on the table below.The number of the column indicated with x stands for the fig. of the nipple valid forsuch Country and coincide with the number used for the indication of bottleconnection in the designation code (ch. 10.5).Each nipple has an own code (indicated on) to be used for spare parts orderand not on the designation of the pre-loading set.

10.6 Connection charging hose - pressure reducer

Installation11

24

11.1 General

The EPE piston accumulators come equipped with, after being test-ed and thoroughly checked at the factory, perfectly correspondent tothe order specifications stamped on the name plate fitted at thegas valve section of each accumulator.The following is stamped on the name plate:

• Maximum working pressure PS in bar

• Value of pre-charge Po in bar (sticky label)

• Accumulator manufacturers number.

• The trade mark CE with certifying authority Nº (only when thestandards are applied)

• Date of manufacture month/year

• Fluid groups

• Name, logo, nationality, manufacturers and telephone numberATTENTION: The maximum working pressure stamped on theaccumulator should be equal or higher than the calibration pressureof the income limit valve of the hydraulic circuit.Before carrying out interventions (repairs, replacements etc.) onand installation, filled with an accumulation, it is necessary to com-pletely discharge the liquid pressure and gas pressure.The conformity and test certificates are supplied with eh accumula-tor, unless otherwise stated.

11.2 Preliminary Checks

To the reception you assure that:

• The accumulator did not sustain damages during transportation.

• The specifications on the name plate correspond to the order.

11.3 Installation

The best efficiency is generally obtained by installing the accumula-tor as near as possible to the utility. The optimal installation posi-tion is vertically, with the nitrogen valve in the upper position, how-ever a horizontal installation is also acceptable.It is recommended that:

• Leave necessary space for use of pre-charge equipment.

• The pre-charge fastening method using supplied “U” bolts like inFig. 18 (See chapter 9). The hydraulic connections must notcarry the weight of the accumulator.

It is absolutely prohibited to weld mounts or alter the body of theaccumulator.

• Provide a filter on pressure side of hydraulic system

• Provide a check valve between pump and accumulator.

• Ensure that the pressure limitation valve of the circuit is directlyconnected to the accumulator and calibrated to an inferior valueof the operational pressure stamped on the accumulator specifi-cation plate.

It is advisable to provide an interception and discharge valve. inorder to isolate the accumulator (to check or for repairs) during theoperation of the plant. All these functions are obtainable with theapplication of the connector block EPE series BS, eliminating bulkyconnectors (See chapter 13 catalog 1007 related to bladder accu-mulators)

11.4 Commissioning

The AP series accumulators are supplied, unless otherwise speci-fied, with a pre-charge pressure of 30 bar.Before commissioning, it is necessary to verify that:

• The pre-charge pressure corresponds to the value requested andor provided.

We generally remember:Po = 0,95 – 0,97 P1 (Energy reserve etc.)Po = 0,8 P1 (Anti-pulsation)Po = 0,6 – 0,9 P1 (Anti water hammer)An incorrectly chosen pre-charge pressure is frequently the causeof bad operation of the plant and can negatively influence thelongevity of the accumulator. The pre-charge value indicated onthe name plate (For all accumulators provided with pre-charge) isrelative to a temperature of 20 ºCFor accumulators provided without pre-charge, or subsequent torepairs, it is necessary to inflate with nitrogen and verify with appro-priate apparatus type PC/… following procedure indicated in chap-ter 12.FOR PRE-CHARGE USE ONLY AND EXCLUSIVELY DRY NITRO-GEN IN BOTTLES.

11.5 Maintenance

• Regularly verify pre-charge pressure during the first week of com-missioning the plant. If no leaks are found, execute successivechecks after 3 months and successively after 6 or 12 months,according to experiences and conditions of utilization.

• Carry out periodical visual examination of accumulator in order tocheck for corrosion and or deformation.

• Conform to government requirements regarding periodic checksof pressure vessels.

11.6 Repairs

Before disassembly the plant, ensure that there is no residualhydraulic pressure.Completely discharge nitrogen before any maintenance operation.To disassembly and replace components, refer to chapter 13.Use only original EPE spare parts

11.7 Out of Commission

In case the accumulator has to be put out of york, it is necessary toensure that it is completely discharged and the pre-charge valve iscompletely blown down.

Pre-charge and checks12

25

12.1 GeneralFor correct function of the accumulator, it is necessary to maintainthe pre-charge pressure that has to be periodically checked withpre-charge apparatus accessory and check PC250.The same equipment, besides the repair, can be used for variousother functions etc. It is necessary to connect, with a flexible hose,to a nitrogen cylinder fitted with a pressure reducing valve sot thatnitrogen can enter the accumulator very slowly.NITROGEN MUST BE USED, NEVER COMPRESSED AIR OROXYGEN.

12.2 Pre-charge and re-setIf the pre-charge is lower than the prescribed value (or if you shouldpre-charge after a repair) proceed as follows:• Remove gas valve protection cap.• Before assembling the equipment PC250 ensure that knob A is

unscrewed and relief B is closed• Screw by hand, using knurled nut D, and device on gas valve.• Assemble the adaptor to the nitrogen cylinder or pressure-redu-

cing valve.• Connect one side of flexible pipe to adaptor.• Connect loose end of flexible pipe to valve C after removing cap.• Screw, without forcing, knob A, until reading a pressure (If accu-

mulator was already pre-charged)• Slowly open the cylinder pressure reducing valve and keep open

until a pressure slightly higher than required, is reached andthere after shut the valve

• Unscrew knob A and decompress the apparatus with relief B.• Disconnect flexible pipe from check valve C.• Close relief, refit cap on valve C and wait a few minutes so the at

the pressure can stabilize.• Re-screw in knob A until a pressure, slightly higher than required,

is read.• Adjust, by relieving pressure, the pre-charge valve and proceed

to dismantle the apparatus by unscrewing nut D with followingprecautions:

• Completely unscrew knob A without forcing.• Open relief B• Check for leaks at the accumulator inflating valve, using soapy

water.• Re-screw in valve cover

At this point the accumulator is ready to be put into operation.

12.3 Diminution of pre-charge.If pre-charge value is higher than required, opening can drop the pres-sure relieve B until desired pressure is reached.It is advisable to relieve slowly and read definite temperature after afew minute after relieving pressure, thereafter the apparatus can beremoved.

12.4 Verification of the pre-chargeThe operation is simple but must be executed correctly as indicated:• Isolate the accumulator from the plant and discharge the liquid con-

tained under pressure.• Remove gas valve protector cap.• Before assembling apparatus PC250 ensure that knob A is

unscrewed, that relief valve B is closed, that check valve C cap isscrewed on.

• Screw by hand knurled nut D, the apparatus on the gas valve.• Screw knob A, without forcing, until a pressure is read. If value cor-

responds with that prescribed, dismantle the apparatus, byunscrewing nut D, taking precaution of:

• Completely unscrew, without forcing, knob A.• Open relief valve B.

IT IS NECESSARY TO USE A PRESSURE REDUCER TO INFLATETHE ACCUMULATORS (EG. GAMMA LOW PRESSURES) THATHAVE A MAXIMUM EXERCISE PRESSURE INFERIOR TO THAT OFTHE NITROGEN CYLINDER PRESSURE.

NB. The pre-charge apparatus PC250 is fitted with a gauge 0 ÷ 250bars. For pressure checks higher than 250 bars, it is necessary to usesuitable gauge.Even for low pressures the precision of measurement is better using adedicated gauge eg. With a pressure of 30 bars it is advisable to usea bottom scale of 60 bar.

Maintenance13

26

13.1 Maintenance

The best system to guarantee perfect efficiency in the piston accumu-lator is to periodically check every 3 months, the pressure of the pre-charge. By doing so, it is possible to obtain the state of health of theequipment. Whilst carrying out this check, the contingent ambienttemperature must be noted, which could be different of that at the timethat the pre-charge was affected and this could be the cause of anerror. It is necessary to ensure that this measure is taken while thepiston is at the extremity of its stroke on the oil side. This in fact wasthe same position at the time of pre-charge operations. The life spanof the gasket depends on the condition of cleanliness of oil in the sys-tem. The presence of metal particles and impurities has and abrasiveeffect on the cylinder and above all on the seal. It is recommended thefilter be used as a precautionary measure, be it for the piston accumu-lator and all the components (Valves pumps etc.)

13.2 Repairs

For the sudden break down or a planned check, it could be necessaryto dismantle the accumulator and check the components.It is necessary to carry out the operations in order as indicated,remembering never to disassembly anything unless it has bee ensurethat the liquid and gas pressure has bee completely relieved.

13.3 Disassembly the accumulator

• If it is possible not to dismantle the equipment from the plant, com-pletely discharge the pre-charge. Charge, the accumulator withfluid under pressure in a way to bring the piston and the end of thestroke at the gas side.

• Completely discharge fluid pressure.

• Dismantle pre-charge valve

• Before removing flanges, tap the flanges with aluminum hammer inorder to release tension on the side of the thread.

• Screw two screws into the threaded holes and using a bar as alever, unscrew the flanges.

• Push out the piston if you have access at the sides or else pullpiston out using an eyebolt.

• If the accumulator is attached to the plant, discharge all the fluid.

• Clean and degrease all stripped components and carry out allvisual inspection.

• Check the internal surface of the cylinder body which should be bri-ght and free from scratches

13.4 Replacement of gasket

Remove all gaskets from pistons and flanges taking precaution not toscratch or damage the faces.Clean the facesUse an original EPE gasket kit; lubricate all the gaskets and guide inthe piston, taking care not to damage during assemble. Fit to respec-tive faces.

13.5 Assembly of accumulators

• Position the assembly sleeve (See chapter 9.5 and 9.7) from theend where the piston is to be inserted, and after having lubricated;push the piston in towards the internal of the accumulator body.

• With the accumulator vertically positioned, with gas side towardsthe top, pour approximately 0,1 litre of mineral oil on the internalsurface of the accumulator, in order to keep the gaskets lubricatedthe nitrogen chamber and to avoid oxidation as a result of eventualhumid residue of gas.

• After having replaced gaskets and the empty extraction rings fittedon the closure flanges, re-screw them on the accumulator body.

• Re-assemble pre-charge valve.

• Execute pre-charge with nitrogen as indicated in Chapter 12.

13.6 Service EPE

For any question and to together find solutions to any of your prob-lems, do not hesitate to contact the Technical Service or SalesDepartments of EPE ITALIANA, either directly or through our bran-ches and representatives all over the world.

EPE Italiana SrlViale delle Rimembranze di Greco, 45I-20125 Milano - ItalyTel. +39 02 67071076Fax +39 02 67071055e-mail: epeitaliana@epeitaliana.ithttp:www.epeitaliana.it

AUSTRALIASTAUFF CORPORATION PTY LTD24-26 Doyle AvenueP.O. BOX 227 Unanderra NSW 2526Tel.: 0061 2 42711877Fax: 0061 2 42718432E-mail: stauff@stauff.com.au

AUS

BELGIUM + LUXEMBOURGEMAC S.A.Industrialaan 1, Zone Maalbeek1702 Groot-BijgardenTel.: 0032 2 4810211Fax: 0032 2 4810301E-mail: bpa@emac.be

B

BY

BR

CO

SK

RC

L

BIELORUSSIAHYDRO-CONNECT ODOKalinovski st. 53/3220103 MinskTel.: 00375 17 2839420Fax: 00375 17 2839767E-mail: info@hydro-connect.com

BRAZILHT-HIDRAUTRONICA ICEI LTDARua: E. Volpini, 45 - Sao J. BatistaCEP: 31515-190 Belo Horizonte - Minas GeraisTel.: 0055 31 34941657Fax: 0055 31 34941831E-mail: gsf@hidrautronica.com.br

COLOMBIAHYDRÁULICA Y NEUMÁTICA LTDACra. 50FF No.7 Sur-17Apartado Aereo No.49204 MedellinTel.: 0057 4 3621600Fax: 0057 4 3620969E-mail: turbinas@hidraulicayneumatica.com.co

SLOVAKIA REPUBLIC + HUNGARYHYDRAULIK INNOVATION GMBHOberbreitenstrasse, 17a4050 Traun/LinzTel.: 0043 7229 516660Fax: 0043 7229 5166614E-mail: Hydrinno@aon.at

CHINASTAUFF (SHANGAI) INTERNATIONALTRADING CO. LTDShangdian Mansion,331 Binzhou Rd., Pudong, Shangai 200126Tel.: 0086 21 58456818Fax: 0086 21 58456680E-mail: stauffsh@public.sta.net.cn

DK DENMARKPMC TECHNOLOGY A/SKlausdalsbrovej, 11 - 2860 SoborgTel.: 0045 70 212121Fax: 0045 70 212122E-mail: info@pmctechnology.dk

F FRANCEABDON S.A.R.L.11, Rue Louis Blanc - 13400 AubagneTel.: 0033 4 42842046Fax: 0033 4 42842072E-mail: christian.abdon@wanadoo.fr

GB GREAT BRITAINEPE (U.K.) LTD16 Manor Industrial EstateFlint, Flintshire, CH6 5UYTel.: 0044 1352 730720Fax: 0044 1352 730820E-mail: epe.uk@btconnect.com

GREECEHYDRAULIC TECHN. O.E.SARAFIANOS BROSSMonastiriou 100 - 54627 ThessalonikiTel.: 0030 2310 525523Fax: 0030 2310 516531E-mail: isip@otenet.gr

GR

ATHENS HYDRODYNAMIC S.A.56, Athinion Avenue - 10441 AthensTel.: 0030 210 5221155Fax: 0030 210 5221485E-mail: hydrodyn@otenet.gr

NL

IND

IL

ROK

MAL

HOLLANDEPE GOLDMAN B.V.Admiraal Trompstraat, 43115 HH SchiedamTel.: 0031 10 4269999Fax: 0031 10 4269080E-mail: sales@epe-goldman.com

INDIAEPE PROCESS FILTERS & ACCUMULATORS PVT. LTD.59-A, C.I.E., Gandhinagar, BalanagarHyderabad 500 037Tel.: 0091 40 23085750Fax: 0091 40 23086781E-mail: business@epe-india.com

ISRAELOZ HYDRAULICS & PNEUMATICS LTDNo.5 Horkanus, North Ind. Area71293 LodTel.: 00972 8 9777640Fax: 00972 8 9777679E-mail: oz-hydraulics@oz-hyd.co.il

KOREALEE HWA SPECIAL TRADING CO., LTDRA 1323 Chungang Complex, Guro-DongGuro-Ku, Seoul 152-721Tel.: 0082 2 26165511Fax: 0082 2 26167545E-mail: KEG9463@chollian.net

MALAYSIAPOWERMATICS HYDRAULICS & ENGINEERING (M) SDN. BHDNo.7 Lengkuk Keluli 2, Kaw Perindustrian BukitRaja, 41050 Klang, SelangorTel.: 0060 3 33448000Fax: 0060 3 33446000E-mail: sales@powermatics.com

MEX MEXICOALFA HIDRAULICA S.A.A. Gonzales 244 col. Sta M. AztahuacanC.P. 09570 - D.F.Tel.: 0052 555 6923077Fax: 0052 555 6923495E-mail: alfahi@prodigy.net.mx

MA MOROCCOGT MAROC S.A.R.L.47, Zankat MarmouchaLa Villette - 20300 CasablancaTel.: 00212 2 2623667Fax: 00212 2 2623811

N NORWAYSERVI MOTION CONTROL ASHaugenveien, 2 - 1402 SkiTel.: 0047 64 979797Fax: 0047 64 979899E-mail: servi@servi.no

POLANDF.E.H. FABRIKA ELEMENTOW HYDRAULIKI S.A.Ul. Wojska Polskiego, 2934100 WadowiceTel.: 0048 33 8234441Fax: 0048 33 8233840E-mail: ponar@ponar-wadowice.pl

PL

SINGAPOREPH HYDRAULICS & ENGINEERING PTE. LTD27 Gul Lane, Jurong629421 SingaporeTel.: 0065 6861 2000Fax: 0065 6861 5000E-mail: phhyd@singnet.com.sg

SGP

SLO

ZA

E

CH

SLOVENIANLE-TEHNIKA, d.o.o.Suceva ulika, 274000 KranjTel.: 0086 4 2042121Fax: 0086 4 2042122E-mail: hydraulic@le-tehnika.si

KLADIVAR ZIRIIndustrijska c. 2, p.p. 144226 ZiriTel.: 00386 4 5159100Fax: 00386 4 5159130E-mail: kladivar@kladivar.si

SOUTH AFRICAGOLDQUEST INTERNATIONAL HYDRAULICS LTDP.O. BOX 4299 - 26 Barney Road2094 Benrose - JohannesburgTel.: 0027 11 6142004Fax: 0027 11 6142033E-mail: admin@goldquest.co.za

SPAINTECONASA SUMINISTROS S.A.Avda. Carlos Marx, 80Poligono Ind. Horno de Alcedo - 46026 ValenciaTel.: 0034 96 3182010Fax: 0034 96 3182275E-mail: teconasa@teconasa.com

SWITZERLANDHINEL AGIndustriestrasse, 2 - 3178 BösingenTel.: 0041 31 7478881Fax: 0041 31 7479827E-mail: Hinel@datacomm.ch

ROC TAIWANLIMIT TEIN INDUSTRIAL CO., LTD3F-7, No. 4, Lane 609, Sec. 5 - Chung Shin Rd.Sanchung City, Taipei Hsien, 241, R.O.C.Tel.: 00886 2 29995022Fax: 00886 2 29995055E-mail: limitein@ms33.hinet.net

T THAILANDPNEUMAX CO., LTD104/21 Moo 8, Chaloem Phrakiat R.9 Rd.Pravet, Bangkok 10250Tel.: 0066 2 7268000Fax: 0066 2 7268260E-mail: import@pneumax.co.th

TR TURKEYMERT TEKNIK FABRIKA MALZEMELERITicaret ve Sanayi A.S.Tersane Cad. 43, Karakoy - 80000 IstanbulTel.: 0090 212 2528435Fax: 0090 212 2456369E-mail: info@mert.com

Branches and representatives all over the world22®

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