Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss

MARINE TANK GAUGING

Substantial improvements in magnetostrictive liquid level sensors have recently

been achieved, making them more attractive for use in automatic tank gauging (ATG)

systems.

The improvements include flexible probes that are much easier to

install and bottom-referenced probes which allow for more accurate

readings for a storage tank. Such liquid level sensors are the key

element in magnetostrictive tank gauges, which offer certain

advantages over other types of automatic tank gauges.

Common types of ATGs include radar, magnetostrictive,

hydrostatic, servo, float and tape.

Radar gauges are popular for their accuracy. They are particularly useful

in gauging tars and other products not suitable for contact-type sensors.

On the other hand, for liquids that can accommodate a float, a bottom-references

magnetostrictive tank gauge (MTG) can provide superior accuracy.

It is not affected by motion of the tank top. In addition, it can incorporate averaging

temperature measurement into its liquid level probe. Hydrostatic tank gauges provide direct

reading of mass

but are less accurate for level. Servo-powered gauges can provide good accuracy but have

a higher installed cost. Float operated tank gauges widely used in the past are losing

popularity due to maintenance demands.

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

TToouucchh SSccrreeeenn aanndd LLCCDD ccoommppuutteerr

bbaasseedd ssyysstteemmss,, ttoo ccoonnssoollee mmoouunntteedd

ggaauuggee ssyysstteemmss..

OOuurr ssyysstteemmss aarree aabbllee ttoo iinntteerrffaaccee

wwiitthh ttrraaddiittiioonnaall 44--2200mmAA ssiiggnnaallss aass

wweellll aass FFiieellddbbuuss,, MMooddbbuuss

aanndd ootthheerr ffiieelldd ssiiggnnaallss aanndd pprroottooccoollss..

BBlloooommffoossss hhaass tthhee ccoommpplleettee ssttrreennggtthh

aanndd ccaappaabbiilliittyy ttoo ddeessiiggnn aanndd

mmaannuuffaaccttuurree TTaannkk MMaannaaggeemmeenntt

SSyysstteemmss ttoo mmeeeett

IIMMOO,, CCLLAASSSS rreeqquuiirreemmeennttss aanndd ffuullffiillll

oowwnneerr eexxppeeccttaattiioonnss..

OOVVEERRVVIIEEWW

BBLLOOOOMMFFOOSSSS TTaannkk SSyysstteemmss

o RADAR systems – Frequency

Modulation Continuous Wave (FMCW)

o GUIDED RADAR systems

o HYDROSTATIC PRESSURE systems

o PNEUMATIC / Electro – Pneumatic

Systems

Other Systems :

o Loading Computer systems

o Anti-heeling & Stability systems

o Alarm & monitoring systems

o Vapour Pressure, monitoring systems

o Temperature monitoring systems

oo CChheemmiiccaall TTaannkkeerrss

oo PPrroodduucctt TTaannkkeerrss

oo CCrruuddee OOiill TTaannkkeerrss

oo FFPPSSOO

oo FFSSOO

oo GGaass TTaannkkeerrss

oo BBaarrggeess && mmaannyy ootthheerrss

Illustration of an FPSO…………

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

CONFIGURATION

Feature

CARGO LEVEL MEASUREMENT

CARGO TEMPERATURE MEASUREMENT

CARGO OVERFILL MONITORING

CARGO VAPOUR PRESSURE & LOAD MONITORING

INERT GAS PRESSURE MONITORING

BALLAST MEASUREMENT

DRAFT MEASUREMENT

ANTI HEELING & STABILITY TEST

HULL STRESS MONITORING

Solution

A complete solution to our customers comprises of

key components ranging from Field Instruments, data

acquisition systems, processors and human machine

interface (HMI) devices.

Backed by strong support from Allen Bradley,

Siemens and GE, Vega & Krohne.

Our team of engineers with over 20 years of

experience in Marine and offshore not just build

systems, but design systems

totally reliable and proven.Illustration of a software based Tank managementsystem…..

Bloomfoss is a trademark of Bloomtorq USA.

TM bloomfoss tank management

RADAR SYSTEMS

Bloomfoss works closely with recognized radar equipment manufacturers to complete the

Marine Radar Tank Gauging solution.

Makers we work with are Vega and Krohne. On certain projects we also work with SAAB and

Auxitrol to give our customers a complete solution and proven solutions.

NORR systems believe in delivering proven solutions to our customers.

Vega Radar

VEGAPULS 62 is a radar sensor in K-band technology

(emitting frequency approx. 26 GHz) for continuous level

measurement.

The version with "thread and horn antenna with

ø 40 mm (1.6 in)" is particularly suitable for small tanks

and process vessels for measurement of virtually all

products.

The version with "flange and horn antenna with ø 48

… 95 mm (ø 1.9 … 3.7 in)" is particularly suitable for

storage tanks and process vessels, for measurement of

solvents, hydrocarbons and fuels under most difficult

process conditions.

The version with "parabolic antenna" is particularly

suitable for precise measurement of products with small

dielectric value. The antenna of the radar sensor emits

short radar pulses with duration of approx. 1 ns.

These pulses are reflected by the product and received by the antenna as echoes. The running

time of the radar pulses from emission to reception is proportional to the distance and hence to

the level.

The determined level is converted into an appropriate output signal and outputted as measured

value. Power supply is via the Profibus DP/PA segment coupler or VEGALOG 571 EP cards.

A two-wire cable acc. to Profibus specification serves as carrier of both power and digital data

signals for multiple sensors.

By the use of a standpipe, influences of vessel installations and turbulence can be excluded.

Under these requirements, the measurement of products with low dielectric values (from DK

value 1.6) is possible. Surge or bypass tubes must extend all the way down to the requested

min. level, as measurement is only possible within the tube.

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

Krohne Radar

Range of applications

The BM 70 M Level-Radar level gauging system is designed to

measure the distance, level, volume and reflection of liquids,

pastes, slurries, solids and particulate materials.

BM 70 M Ex hazardous-duty versions are suitable for use in Ex-

Zone 0, 1 and 2.

Operating principle (FMCW-Radar)

A radar signal is given via an antenna, reflected on the measuring

surface and received after a delay time t.

FMCW: Frequency Modulated Continuous Wave

The FMCW-radar uses a high frequency signal (~10 GHz) which

transmits frequency increasing linearly 1 GHz during the

measurement (frequency sweep) (1). The signal is emitted,

reflected on the measuring surface and received time-delayed (2).

For further signal processing the difference ∆f is calculated from the actual transmit frequency

and the receive frequency (3).

The difference is directly proportional to the distance i.e. a large frequency difference

corresponds to a large distance and vice versa. The frequency difference is transformed via a

Fourier transformation (FFT) into a frequency spectrum and then the distance is calculated from

the spectrum. The level results from the difference between tank height and distance.

Linearity of frequency sweeps

The measuring accuracy of an FMCW radar is determined

from the linearity of the frequency sweeps and their

reproducibility. The linearity correction is deduced via

reference measurement of the oscillator.

An immediate frequency regulation is necessary with

the BM 70 M device because of the higher

demand on the measuring accuracy.

With the PLL technology (Phase Locked Loop) the

signal frequency is directly recorded as a

digital data and the converter oscillator locks

automatically on the right frequency.

BM70 M radar

Illustration of FM - CW

Bloomfoss is a trademark of Bloomtorq USA.

B bloomfoss tank management

- setup- indep- insens- probe- signalanalysi- instru

Version

Measurrange

Proces

Procestemper

Procespressur

Accura

GUIDED - RADAR SYSTEMS

Measuring principle

High frequency microwave pulses are coupled on a cable or rod and guided

along the probe. The pulses are reflected by the product surface and received

by the processing electronics. A microcomputer identifies these level echoes

which are measured, evaluated and converted into level information by the

ECHO-FOX software.

Thanks to this measuring principle, the adjustment with the medium is no

longer necessary. The instruments are preset to the ordered probe length.

The cable and rod versions (shortable) can be adapted locally to the individual

conditions.

Insensitive to dust, steam and product fluctuations

Even process conditions such as high dust and noise generation or very

steamy atmospheres do not influence the accuracy of the measurement.

Density fluctuations, different granulation sizes or even fluidization do not

influence the accuracy. Even changes from dry to wet gravel are no problem.

Strong buildup on the probe or the vessel wall does not influence the

measurement result.

Interface measurement in liquids

Apart from the continuous level measurement of solids and liquids,

the principle of the guided microwave was further developed for

interface measurement.

Typical applications are measurement of

oil and water or solvents and water.

The microwave pulse is guided along a rod or rope and

reflected by an interface with different dielectric value.

The advantage compared to displacers and floats is that

the measuring principle is independent of the density

and does not use any moving parts.

Maintenance-free operation is therefore guaranteed.

Applications

- Level measurement of solids and liquids

Advantages in an overview

without adjustmentendent of product featuresitive to dust, vapour and buildup

s can be shortenedprocessing ECHOFOX for echo

s with Fuzzy-Logicment from the plics® family

with exchangeable cable (ø4 mm) or rod (ø 6 mm)

ing cable: up to 32 mrod: up to 4 m

s fitting from G ¾ A

sature

-40…150°C

se

-1…40 bar(-100…4000 KPa)

cy +/- 5 mm

Bl

BTM bloomfoss tank management

HYDROSTATIC PRESSURE

In the case where the fluid is at rest, called fluid statics or hydrostatics (from hydro meaning "water" and

static meaning "at rest"), the force acting on the object is the sheer weight of the fluid above, up to the

water's surface—such as from a water tower. The resulting hydrostatic pressure (static pressure) is

isotropic: the pressure acts in all directions equally, according to Pascal's law:

VEGAWELL 72 pressure transmitters work acc. to the hydrostatic

measuring principle, which functions independently of the dielectric

properties of the product and is not influenced by foam generation.

The sensor element of VEGAWELL 72 is the dry ceramic-capacitive

CERTEC® measuring cell.

Base element and diaphragm consist of high purity sapphire-ceramic.

The hydrostatic pressure of the product causes via the diaphragm a

Capacitance change in the measuring cell.

This capacitance change is converted into an appropriate output signal

On board vessel, the VEGAWELL 72 is well suited for Ballast tanks

whereby submersion in seawater do not affect the long term accuracy of

the transm

This is shown schematically in Figure above.

- dry, c- long t- two w- diame- integr

Measur

Cable m

Diamet

Produc

Illustration of VEGAWELL 72

itter.

Advantages in an overview

eramic-capacitive sensor elementerm stability 0.1%/2 yearsire system 4...20mAter of the transmitter 32 mmated overvoltage protection

ing cell CERTEC®

oomfoss is a trademark of Bloomtorq USA.

aterial PE/PUR/FEP

er 32 mm

t temperature up to 85°C

Bloomfoss is a trademark of Bloomtorq USA.

BTM tank management

Shipboard Applications

Protection on-board and dock equipment

Monitoring the pipeline pressures at the manifold ensures the safety

of on-board and dock equipment, and provides the basis for pump control.

If pump output is too high or if valves remain closed during charging and

discharging processes, gauge or low pressure in the product pipelines

can result.

This can damage the manifold or the storage tanks.

On-site pressure indication provides additional security for processes

involving the manifold. Choosing an appropriate pressure instrument

becomes therefore crucial for this particular application whereby location

indication is just as important as remote readout.

Draught, trim and list

The most important measurements on board are the measuring points

for calculating draught, trim and list. Ship safety depends heavily on them.

Using the transmitted values from the different measuring points, the load

master, as part of the cargo control system (CCS), can determine the exact

values of ship orientation and draught.

Usually, two measuring points forepeak and two additional measuring

points afterpeak are used.

Instruments with appropriate protection of IP68 will have to used for this

application.

Service and settling tank

To ensure fuel feed to the main engine, the separated heavy fuel oil

(HFO) is first pumped into the settling tank (buffer tank).

The connected service tank (day tank) is filled via continuous overflow

from the settling tank and is connected directly with the main engine.

Heating coils in both tanks ensure an even temperature between +75° and

+90°C (+167° and +194°F) which keeps the oil pumpable.

Choosing the correct apparatus that can withstand the high temperature

and sludge environment is therefore very important for the long term life

of the apparatus. We would recommend an equipment which has

minimum contact to the heat and heavy oil, as a guided radar instrument.

Bloomfoss is a trademark of Bloomtorq USA.

BTM tank management

Monitoring the bilge

Every motorised ship has a so-called bilge well, i.e. a space between the

floor of the engine room and the bottom of the ship. A water/oil mixture

collects in this space at the lowest point of the ship. The mixture is then

separated into water and oil by an on-board skimmer and demulsifying unit.

After passing through various cleaning processes, the water can be pumped

out. The bilge de-oiling equipment is controlled by level switches

Bloomfoss recommends highly reliable level switch for this application to

minimize the changing of this instrument over long periods.

Fresh water and grey/black water

Fresh water is an essential commodity on a ship. It is stored in separate

dedicated tanks. Depending on the type and size of the ship, different

amounts of fresh water are required for drinking, for personal hygiene as well

as for cleaning. The amount of water stored in the tanks can be from

50 to 400 tons and depends largely on whether the ship has a desalinisation

plant. Direct electrical measuring principles are mandatory for level

measurement. Waste water, so-called grey/black water, is treated on large

ships in on-board clarification plants, or stored in special grey/black water

tanks to await final disposal.

Grey water measurement

Due to the large concentration of solids and the changing density of the

tank contents, non-contact measurement with ultrasonic technology qualifies

well for this application

Fresh water measurement

Bloomfoss recommends flange side-mounted instruments for fresh water applications.

Flanged directly onto the tank, level can be measured reliably and accurately. Materials

approved for drinking water and a front-flush diaphragm form the basis of a flawlessly

hygienic measurement.

BTM bloomfoss tank management

TECHNICAL LITERATUREGuided-wave radar technology today is offering operators more level-detection

capabilitiesthan ever before possible when the application calls for measuring bulk solids, liquids, and

everything in between.

For an ever-widening range of previously hard-to-measure products such as molten sulfur,

liquid ammonia and petrochemicals, guided-wave radar transmitters provide accurate level

measurements even under harsh

chemical environments, wide

variations in operating

temperatures and pressures,

and low dielectric constants.

Developers also have taken

great strides in making the units

easier to configure for a variety

of process

applications coupled

with the simplicity of integrating these devices with most digital communication protocols.

These improvements come as welcome relief to process engineers within an expanded

range of level applications across several different industries that seek solutions to

measuring the contents of tanks, silos, hoppers, bins, mixing basins, and vessels.

A quick examination of how guided wave technologies compare against other time-of-flight

technologies, such as through-air radar and ultrasonic –along with a discussion of

application guidelines - can serve to elucidate the benefits that this new technology can

bring to engineers needing to improve process operations.

Because radar transmitters have no moving parts, radar has already established

a dominant niche in level measuring that quickly distances itself from mechanical means,

which don’t hold up as well in dirty service. Radar achieves its non-mechanical level

detection capability by measuring the time of flight of the transmitted signal.

Known more accurately as Time Domain Reflectometry (TDR), the process involves

sending microwave energy down into a vessel. When the pulse of radar energy reaches the

product (indicated by a change in impedance), part of the pulse is reflected back toward the

transmitter. A receiver measures the exact duration of time between the transmitted and

reflected signal — the “time of flight.” The device analyzes the time and ultimately displays

the level of the product as a distance in feet, meters, or other engineering units. Through-air

technology clearly pioneered the way for radar in terms of level measurement.

Guided Wave Vs Radar

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

However, one of the major problems of non-contact (with the product to be measured)

through-air radar, is the high probability of false echoes. Simply pointing a radar transmitter

toward the bottom of a silo allows unguided waves to bounce off the sides of the silo itself,

returning many divergent signals that must be canceled out at the receiving end. Part of the

problem stems from the wide dispersion of radar beams, which radiate away from the

transmitting antenna in the shape of an ever-widening cone. A similar problem also presents

itself in ultrasonic measurements where divergent angles of up to 20 degrees are routine.

These obstacles have now been overcome with the arrival of guided-wave radar transmitters. While

fundamentally relying on the same conventional time-of flight technology used in through-air radars,

guided-wave radars go one step further by controlling the spread of radar beams via a “probe” that is

introduced directly into the product to be measured. Typically, the wave-guide is a specially designed

metal rod or cable. Since the guide concentrates the radar signal within a small-diameter (often less

than 12 inches) cylinder along the probe, it doesn’t disperse and reflect off of materials that are not

representative of product level. This results in a higher level of performance and reliability from the

guided wave device.

Probe Vs. Through-Air Technology

While non-contact instruments — radar and ultrasound — are susceptible to false returns,

the basic theory behind guided wave radar helps prevent false echoes in the first place.

Complicated configuration is not necessary. Any adjustments can typically be accomplished

via push buttons within the instrument itself.

Signal Strength

At first glance, it might seem easy to increase the signal-to-noise (S/N) ratio by simply

increasing the power of the transmitted radar signal. Flying in the face of this assumption,

however, is the fact that there is a very limited amount of power available to operate the

electronic and sensor circuits in order to use the industry- standard analog output of 4-20

mA with a loop powered transmitter.

A fundamental advantage in guided wave technology is that less energy is required. This is

because the microwaves are concentrated along the wave-guide. Guided-wave radar allows

the concentration of energy where it is needed the most. Therefore, less power is required

with guided waves. This in turn contributes to a higher S/N ratio.

Fast Response Time

Guided-wave radar operates on a faster time cycle than non-contact radar. Guided wave

can take up to 10 readings per second, yielding an almost instantaneous response. Results

can then be updated at this rate if no additional filtering is needed.

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

Overcoming Dielectric Obstacle

Obtaining accurate readings in products with a low dielectric constant provides the greatest

challenge to most radar transmitters, as it becomes increasingly difficult to obtain a reflected

signal. Radar waves partially pass through non-conductive materials like liquid propane or

butane, making it traditionally difficult to obtain accurate levels. In both guided-wave and

through-air radar, the coax cable that carries the signal from the transmitter to the process

connection typically has an impedance of 50 ohms. Ideally, if one could maintain that same

impedance along the entire length of travel of the radar beam, then all of the reflected signal

would bounce off of the product. In actuality though, when going from coax to air, a large

impedance change occurs leading to a substantial loss of signal.

Guided-wave radar sidesteps the challenge of measuring low dielectric products

by using a single probe that is protected by a stainless steel tube that functions like a small

concentric shield surrounding the entire probe length giving the whole assembly a coaxial

structure.

The tube acts as a ground plane to help channel the energy. It maintains constant

impedance along the entire wave-guide. The coaxial sensor can then detect more

subtle dielectric changes, and correctly indicate the level of the product. Through-air radar

can also use a similar pipe arrangement to channel energy and measure lower dielectrics.

However, for through-air radar this mode of operation is much more susceptible to build-up

and is very dependent on pipe configuration and construction. Guided-waver radar

transmitters also allow special probe configurations to perform indirect measurements by

taking into account the velocity change of the energy as it travels through the product. In this

manner, very low dielectric products, typically down to 1.3, can be measured in applications

where other methods have failed in the past.

Measuring Long Spans

Guided-wave radar is more suitable for measuring tall tanks because its microwave energy

is focused and travels along the wave-guide, which makes the technology more suitable for

long measuring lengths particularly with low dielectric products.

Conclusions

GWR is becoming the measurement method of choice for specific applications such as

crude oil, butane and propane. Considering all of the above, engineers can expect an

orderly future when it

comes to accurately determining the level of product in their vessels tanks, bins,

silos and hoppers.

by Eric Fauveau, VP Research & Development, K-TEK, Prairieville, LA, andKevin Hambrice, Director Marketing, K-TEK, Prairieville, LA

Bloomfoss is a trademark of Bloomtorq USA.

BTM bloomfoss tank management

Dielectric material

A dielectric material is a substance that is a poor conductor of electricity, but an efficient

supporter of electrostatic fields. If the flow of current between opposite electric charge poles

is kept to a minimum while the electrostatic lines of flux are not impeded or interrupted, an

electrostatic field can store energy. This property is useful in capacitors, especially at radio

frequencies. Dielectric materials are also used in the construction of radio-frequency

transmission lines.

In practice, most dielectric materials are solid. Examples include porcelain (ceramic), mica,

glass, plastics, and the oxides of various metals. Some liquids and gases can serve as good

dielectric materials. Dry air is an excellent dielectric, and is used in variable capacitors and

some types of transmission lines. Distilled water is a fair dielectric. A vacuum is an exceptionally

efficient dielectric.

An important property of a dielectric is its ability to support an electrostatic field while dissipating

minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as

heat), the more effective is a dielectric material. Another consideration is the dielectric constant,

the extent to which a substance concentrates the electrostatic lines of flux. Substances with a

low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as

helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled

water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric

constants.

The prime asset of high-dielectric-constant substances, such as aluminum oxide, is the fact that

they make possible the manufacture of high-value capacitors with small physical volume. But

these materials are generally not able to withstand electrostatic fields as intense as low-

dielectric-constant substances such as air. If the voltage across a dielectric material becomes

too great -- that is, if the electrostatic field becomes too intense -- the material will suddenly

begin to conduct current. This phenomenon is called dielectric breakdown. In components that

use gases or liquids as the dielectric medium, this condition reverses itself if the voltage

decreases below the critical point. But in components containing solid dielectrics, dielectric

breakdown usually results in permanent damage.