PRESSURE SWITCHESHIGH RANGE

WEATHERPROOFFLAMEPROOF

SERIES 931

BOURDON OPERATED 316 SS WETTED PARTS MULTI SETTINGS HIGH REPEATABILITY

SWITZER series 931 Pressure Switches are thelatest addition to the main stream. These are verysimple in construction, employing time proven German‘C’ and coiled bourdon of 316 SS ( Ti ) material. Oneor two microswitches are directly operated by the

bourdon tube. The pressure is set by the rangeadjustment screw for each microswitch and the settingadjustments are independent. The instrument isavailable both in weatherproof and flameproofenclosures.

Enclosure

GM Aluminium Pressure die castWeatherproof to IP:66

GA 304 / 316 SS, investment castweatherproof to IP:66

GK Aluminium die cast, weatherproofto IP:66 & flameproof to Gr.IIA, IIBor IIC (Note 1)

Ranges 0 – 1.6 to 0 – 600 bar.Refer table

Sensor SS 316 ( Ti ) Bourdon Tube

Wetted Parts SS 316

On–off Diffl. Fixed. Refer table

Adjustable differential optionalvia Power Relay. Refer page 3.

Repeatability ±1% FSR (Note 4)

Setting Internal adjustment with locking

Switching Instrument quality snap acting SPDTmicroswitch

No. of Switches 1 or 2 independently adjustablePossible settings for 2 switches :a) High & Low; b) Very Low & Low;c) High & Very Highd) Synchronised within practical limits

to act at same point on falling orrising signal to provide DPDT action.

Max. WorkingPressure Refer table

Max. Temperature

Process 200°C (Note 11)

Ambient 0 to 60°C (Note 10)

ConnectionProcess Standard 1/4" NPT(F). Other

connections through adaptors.

Electrical 3/4" ET(F) Std.1/2" NPT(F) optional.Dual Entry on request

Mounting Direct on-line

Conformity Generally to BS: 6134:1991

MODEL 931 IN GM ENCLOSURE MODEL 931 IN GK ENCLOSURE

GENERAL SPECIFICATIONS

ENCLOSUREAluminium pressure die cast weatherproofto IP:66 with Nitrile gasket. –––––––––––––– GM304 / 316 SS investment cast weatherproofto IP:66 with overall size as style GM – foraggressive atmospheres. Fit for offshore. –– GAAluminium die cast flameproof cumweatherproof. CIMFR approved to Gr.IIA,IIB & IIC of IS:2148:2004 for flameproof-ness and IP:66 for weatherproofness. ––––– GK

MODELBasic Pressure Switch with fixed differentialoperated by Bourdon tube. Setpoint fieldadjustable over full range. –––––––––––––––– 931

MATERIALS OF WETTED PARTS316 SS (Titanium stabilised) Bourdon tube and316 SS process connection –––––––––––––––––– 6

RANGE CODE AND SWITCHING DIFFERENTIALRefer Table – 1 ––––––––––––––––––––––––––––––

SWITCH CODE RATING AND AVAILABILITYRefer Table – 2 –––––––––––––––––––––––––––––––––

ELECTRICAL ENTRY CODERefer Table – 3 –––––––––––––––––––––––––––––––––––

No. OF SWITCHESSingle Switch ––––––––––––––––––––––––––––––––––––––– N

Two Switches –––––––––––––––––––––––––––––––––––––– M

DIFFERENTIAL OPTIONFixed on-off differential –––––––––––––––––––––––––––––––––– 0

Relay unit in independent weatherproof housing foradjustable switching differential –––––––––––––––––––––––––– 1

NOTE :The simplified design with minimal moving components allowseach of the two microswitches to be independently adjusted overthe entire range. But it does not provide for switching differentialadjustment.However two switches can be set at two different points andinterlocked using an auxiliary relay to provide wideband differentialfeature.Switzer can supply the relay unit “Power Relay – Model 150”, ifspecified while ordering. Refer page 3 for details.

ORDERING INFORMATION

Damping coil for minimising process pulsations — increasesinstrument’s life many times.Blow out protection for weatherproof and flameproof enclosures.Snubbers, pigtail syphons, over-range protectors.Brass / 316 SS double compression cable glands to suit cableOD of 1/2", 15 mm & 17 mm.Degreasing for Oxygen service & special parts for Ammoniaservice.Provision of line fault monitoring.

OPTIONS / ACCESSORIES

EGNAR EGNAR EGNAR EGNAR EGNAREDOC

EGNAR EGNAR EGNAR EGNAR EGNAR)RABni(

PWM PWM PWM PWM PWM)RABni(

5G 6.1ot0 1.22C 5.2ot0 3.36A 4ot0 2.53C 6ot0 87A 01ot0 318A 61ot0 129A 52ot0 331B 04ot0 252B 06ot0 080V 001ot0 0315U 061ot0 0125V 052ot0 5236V 513ot0 0146W 004ot0 0253Y 006ot0 087

Table–1 : RANGE CODE & SWITCHING DIFFL.

The differential values are at test conditions withcode “3” / “D”, 15A 230V AC SPDT Microswitches.The switching differentials may vary slightly dependingupon operating conditions.For switching differential with other microswitches,consult factory.

Switching Differential ≤≤≤≤≤5% FSRFor Range Codes G5 & C2 Diffl. will be ≤10% FSR

Table–2 : SWITCH CODE, RATING & AVAILABILITY

HCTIWS HCTIWS HCTIWS HCTIWS HCTIWSEDOC

)TDPS(

CACACACACAGNITAR

SPMANIGNITARCD SPMANIGNITARCD SPMANIGNITARCD SPMANIGNITARCD SPMANIGNITARCDEVITSISER EVITSISER EVITSISER EVITSISER EVITSISER EVITCUDNI EVITCUDNI EVITCUDNI EVITCUDNI EVITCUDNI

V022 V022 V022 V022 V022 V011 V011 V011 V011 V011 V42 V42 V42 V42 V42 V022 V022 V022 V022 V022 V011 V011 V011 V011 V011 V42 V42 V42 V42 V42

D /052A51V521 2.0 4.0 0.2 20.0 30.0 0.1

3 /052A51V521 .R.N .R.N .R.N .R.N .R.N .R.N

4 V521A1 .A.N 5.0 5.0 .A.N 52.0 52.0

6 V521A1.0 .R.N .R.N 1.0 .R.N .R.N .A.NCodes 3 & D – For General purpose usages.Code 4 – With Gold alloy contact.Code 6 – With Gold alloy contact (Low Rating)

For DPDT, change switch code to“DD”, “33”, etc., while ordering

N.A. – Not Available N.R. – Not Recommended

eziS eziS eziS eziS eziSyrtnEelgniS yrtnEelgniS yrtnEelgniS yrtnEelgniS yrtnEelgniS yrtnElauD yrtnElauD yrtnElauD yrtnElauD yrtnElauD

AG/MG AG/MG AG/MG AG/MG AG/MG KGKGKGKGKG AG/MG AG/MG AG/MG AG/MG AG/MG KGKGKGKGKGFTE"4/3 A A M MFTPN"2/1 B B N NFTPN"4/3 C --- O ---

.5.1×02M D D P P5.1×61M E --- Q ---

rotcennoChguorhT rotcennoChguorhT rotcennoChguorhT rotcennoChguorhT rotcennoChguorhTgulpnip3 2 --- --- ---gulpnip7 3 --- --- ---gulpnip9 4 --- --- ---

Table 3 : ELECTRICAL ENTRY CODE

Cable gland available on request.Cable Entry is optional. Available on request.

NOTES

1. Gr.IIA & IIB of IS:2148 is equivalent to NEC CL.1, Gr.C& D. Gr.IIC of IS:2148 is equivalent to NEC CL.1, DIV.1,Gr.A & B.

2. Style GM/GA is weatherproof only if all entries and jointfaces are properly sealed. Style GK is weatherproofonly if cover ‘O’ ring is retained in position and flameproofonly if proper FLP cable gland is used. It isrecommended to procure cable glands along with GKinstruments to avoid neglect of it while installation.

3. Intrinsic Safety (Exi) — Pressure switches are classifiedas simple apparatus as they neither generate nor storeenergy. Hence pressure switches in weatherproof (GM/GA) enclosures also may be used in intrinsically safesystems without certification provided the power sourceis certified Intrinsically Safe. Because of the low voltagesand currents it is recommended to use gold contactand / or sealed contacts.

4. Accuracy & Repeatability are not different for all blindpressure switches. A shift of ±2% may be observed insetpoint when pressure falls from full static pressure.Settings will also shift with varying temperature.

5. The instrument is calibrated in the mounting positiondepicted in the drawing. Mounting in any other directionwill cause a minor range shift, especially in low andcompound ranges. Ranges above 1 bar will notexperience this shift.

6. Select working range of the instrument such that theset value lies in the mid 35% of the range i.e., between35% and 70% of range span.

7. On and off settings should not exceed the upper orlower range value.

8. DPDT action is achieved by two SPDT switchessynchronised to practical limits i.e., ±2% of FSR.Deadband for DPDT arrangement are higher than thatof SPDT as force required to actuate two contacts aremore. Please refer Differential table for exact values.

9. Contact life of microswitches are 5 × 105 switching cyclesfor nominal load. To quench DC sparks, use diode in

parallel with inductance, ensuring polarity. A ‘R–C’network is also recommended with ‘R’ value in Ohmsequal to coil resistance and ‘C’ value in micro Faradsequal to holding current in Amps.

10. Ambient temperature range: All models are suitablefor operating within a range of ambient temperaturefrom (–) 10°C to (+) 60°C provided the process doesnot freeze within this range. Below 0°C, precautionsshould be taken in humid atmospheres to prevent frostformation inside the instrument from jamming themechanism. Occasional excursions beyond this rangeare possible but accuracy might be impaired. Themicroswitch is the limiting factor which should neverexceed the limits (–) 50°C to (+) 80°C.

11. Fluid Temperature: A pressure switch when connectedto the process is not subjected to through flow andtherefore is not fully exposed to the fluid temperature.Use of adequate length of impulse piping will greatlyreduce excessive heating of the sensing element. Fore.g., connection of 7.5 cm of 12 mm dia impulse pipingwill reduce water temperature of 100°C to 65°C at anambient temperature of 50°C. Ask factory for pipingnomogram #441184–4 for different temperatures.

12. Ensure that impulse pipework applies no stresson sensing element housing and use spanners tohold pressure port / housing when connections aremade.

13. Pressure switches are available in Series 200 / GH900 with bellows / diaphragm sensor and Series S20/920 with diaphragm sealed piston sensor.Complementary instrumentation for differential pressureis available in Series 300.

14. Custom built instruments are available for specialservice requirements under Special EngineeringCategory.

15. Accuracy figures are exclusive of test equipmenttolerance on the claimed values.

16. All performance data are guaranteed to ±5%.

Model 150 Power Relay is used with Switzer Process ControlSwitches and Differential Pressure Indicating Switches toenhance the contact current rating of primary switching elementsor for contact multiplication.

Model 150 Power relay accepts one or two Reed or Microswitchcontacts as inputs and provides independent potential freerelay contact outputs for each input.

This unit can also be supplied to be used for wideband controlapplications with interlocked inputs.

This relay unit is housed in a Cast Aluminium enclosure withplastic cover and is weatherproof to IP:66.

POWER RELAY – MODEL 150 — FOR ADJUSTABLE SWITCHING DIFFERENTIAL

MOUNTING DIMENSIONS

#031

0 P

S931

– R

ev.1

–2

All dimensions are in mm

GM Housing

GK Housing

Surface Mounting

Pipe Mounting

Pipe Mounting

Notes :Pipe mounting bracket can be usedfor surface / wall mounting also.

Use 2× 3/8" × 25 long screws andnuts for surface mounting or coachscrews for wall mounting instead of‘U’ bolts and nuts.

Fixing onHorizontal Pipe

Fixing onVertical Pipe

2" Pipe Mounting Details

Prior notification of changes in specification is impracticable due to continuous Improvement

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