Measuring Compressed Air Consumption in a Ring Main: Consider Flow Direction, Reverse Flow and the Correct Measuring Point

→ Product category: Flow Measurement Technology

 

A compressed air consumption meter indicates:

1.250 Nm³/h

.

Does this automatically represent the consumption of the connected production hall?

Not necessarily in a branched or ring-shaped compressed air network.

In a conventional branch line, the flow direction is often clear:

Compressor → Main line → Consumer

In a ring main, however, compressed air can supply the same network section from different directions depending on the current operating condition.

For example, the flow may be:

left → right

in the morning and, a few minutes later:

right → left

.

For a reliable consumption balance, it is therefore not sufficient for the flow rate and pipe diameter alone to be correct.

Also decisive are:

• the actual flow direction,
• possible reverse flows,
• the position of the measuring point within the ring,
• the boundary of the consumer to be balanced,
• inlet and outlet conditions,
• the minimum and maximum flow rate,
• the reference standard used for standard volumetric flow,
• the correct processing of negative or reverse-direction flow rates.

The most important question is therefore not initially “Which flow meter do I need?”, but “Which compressed air quantity do I actually want to balance at this point?”

Suitable solutions can be found at ICS Schneider under Flow Measurement Technology and Consumption Meters for Gases and Compressed Air.

Why is measurement in a compressed air ring main more demanding?

Ring mains are used so that consumers can be supplied with compressed air from several directions.

In simplified form:

Compressor station → Ring → Consumer → Ring → Back to main line

This can:

• reduce pressure losses,
• shorten supply paths,
• distribute loads more evenly,
• supply individual areas more flexibly

.

However, this creates a measurement challenge

The flow in an individual section of a ring main does not necessarily have a constant direction.

Its direction depends on:

• which compressors are running,
• which consumers are active,
• which valves are open,
• which pressure losses are currently occurring in the network,
• whether subnetworks are connected or separated.

The same measuring point can therefore

temporarily detect an:

inflow

and, at another time, an:

outflow / reverse flow

.

Why can the flow direction change?

Compressed air generally flows according to the current pressure conditions in the network.

Example

A production hall is connected to a ring main at two points.

On the left side, the pressure is:

7,1 bar

.

On the right side:

6,9 bar

Initially

a larger proportion of the air flows:

left → hall

If a large consumer on the left side of the plant now starts

the pressure distribution can change.

The ring section may then suddenly be supplied from the opposite direction.

This reversal of flow is not necessarily a fault

but can be a normal consequence of:

• the ring-main structure,
• changing consumer load,
• compressor control

.

For the measurement, this means

A flow meter that correctly measures only one direction, or whose evaluation ignores reverse flow, can produce an incorrect balance in a ring-main section.

Correctly distinguishing flow rate and consumption

Two quantities are often confused in compressed air measurements.

Instantaneous flow rate

for example:

Q = 850 Nm³/h

Consumption

is, by contrast, the quantity integrated over time.

In simplified form:

V = ∫ Q(t) dt

At constant flow rate

in simplified form:

V = Q × t

Example

Q = 500 Nm³/h

for:

2 h

results in:

V = 1.000 Nm³

With changing flow direction

the sign becomes relevant.

For example:

+500 Nm³/h

for forward flow and:

-200 Nm³/h

for reverse flow.

Therefore

before evaluation it must be defined whether:

• only the net flow,
• forward and reverse quantities separately,
• or the total transported volumetric flow

is to be recorded.

Define the measurement objective first

The optimum measuring point depends directly on the question to be answered.

Typical measurement objectives include

• total consumption of a plant,
• consumption of a production hall,
• consumption of a machine,
• consumption of a cost center,
• balancing a section of the ring main,
• detecting leaks,
• optimizing compressors,
• monitoring network distribution.

Example

If the consumption of an individual machine is to be determined, a measuring point directly in its branch line is usually much clearer than a measurement in a main line of the ring network.

For a hall balance

several inflows and outflows may need to be recorded.

Therefore

The closer a measuring point is to the clearly defined consumer group, the easier it usually becomes to create a reliable consumption balance.

Selecting the correct measuring point in the ring main

A pipe that is technically easy to access is not automatically a good measuring point.

A suitable measuring point should

• clearly define the desired balance zone,
• provide suitable flow conditions,
• allow sufficient inlet and outlet straight runs,
• be accessible for installation and later calibration,
• avoid excessive condensate at the sensor,
• have a suitable pipe diameter.

Unfavorable position

A measuring point is selected somewhere in the ring simply because an unused connection is already available there.

Problem

The measured value may then simultaneously include:

• consumption of the desired hall,
• supply to a neighboring subnetwork,
• reverse flow from another ring section.

The result

may be a technically correct flow value, but possibly:

not the required consumption value

Clearly defining consumers and subnetworks

Before installation, a simplified piping diagram should therefore first be created.

The following should be marked

• compressors,
• compressed air receivers,
• ring mains,
• connecting lines,
• shut-off valves,
• major consumers,
• existing measuring points.

A balance boundary is then drawn

for example around:

Production Hall A

All lines crossing this boundary

must be taken into account for a complete balance.

If the hall has only one connection

the balance is simple:

Hall consumption = measured inflow

If it has two connections to the ring main

for example, the following must apply:

Hall consumption = Q1 + Q2

with both flow rates taken into account using the correct sign.

Detecting and correctly evaluating reverse flow

Reverse flow does not necessarily mean that compressed air flows back toward the compressors.

What is meant

is that the air flows at a particular measuring point opposite to the defined positive measuring direction.

Example

The sensor is defined for:

A → B = positive

However, the air temporarily flows

B → A

This means there is

negative or reverse-direction flow

.

This can occur, for example

• during load changes,
• after switching off a compressor,
• when a second compressor network is connected,
• when valve positions change,
• because of different consumers within the ring.

Before installation, it should therefore be checked

Can the flow direction reverse at this measuring point?

When is bidirectional flow measurement necessary?

Bidirectional measurement is particularly necessary if the actual flow can:

• occur in both directions
• and both directions are relevant for the balance.

Typical example

A measuring point is located directly in a:

ring main

rather than in a clearly directed consumer branch line.

The measuring system should then

not only detect:

|Q| = 300 Nm³/h

but, if possible, also:

Q = +300 Nm³/h

or:

Q = -300 Nm³/h

The IVA500 listed by ICS

is optionally available for:

bidirectional measurement

.

The IVA520

is also available in a bidirectional version according to the device data provided by ICS.

Important

The required directional function must be taken into account when ordering. A measuring point configured as standard for only one flow direction should not subsequently be interpreted automatically as a bidirectional consumption meter.

Detecting flow direction with a separate direction switch

For compressed air ring mains, ICS also offers the:

IVA 409 Direction Switch

Its primary task is not

to measure actual consumption.

It detects

the flow direction

ICS describes the IVA 409 specifically for

compressed air and gas ring mains

According to ICS, the direction switch detects

even very small changes in flow direction and contains no mechanical wear parts.

The directional information

is provided via a potential-free contact.

In combination with consumption sensors

this makes it possible to distinguish between:

incoming compressed air

and:

outgoing compressed air

.

ICS explicitly specifies the combination

of the IVA 409 with:

IVA500 / IVA520

for measuring incoming and outgoing compressed air in ring mains.

Creating a compressed air balance in a ring main

A balance considers a defined system boundary.

In simplified form

Consumption = Sum of inflows − Sum of outflows

Example

A hall receives through the left line:

Q1 = +600 Nm³/h

and through the right line:

Q2 = +250 Nm³/h

The instantaneous total inflow is therefore

850 Nm³/h

If the network situation changes

and at measuring point 2:

-100 Nm³/h

now flows out of the balance zone, the result is:

600 − 100 = 500 Nm³/h

This makes it clear

When balancing a ring main, the sign of the flow is just as important as its magnitude.

Why a simple totalizer can produce incorrect consumption values

Many flow meters have an integrated consumption meter or totalizer.

In a line with a clearly defined flow direction

evaluation is simple:

Total consumption = Sum of all positive flows over time

When the direction reverses

it must be clearly defined how the device or higher-level software processes:

• forward quantity,
• reverse quantity,
• net consumption

.

For example, it would be problematic

if both:

+100 Nm³

and:

-100 Nm³

were simply added as:

100 Nm³ consumption

each.

The totalizer would then

indicate:

200 Nm³

although the net flow across the balance boundary is:

0 Nm³

.

Therefore, during commissioning it must already be defined

which quantity will subsequently be required:

Forward quantity / Reverse quantity / Net quantity

Considering measuring range and low nighttime consumption

A consumption measuring point must not only record the maximum production consumption.

For energy analyses, low flow rates are often particularly interesting

for example during:

• production shutdown,
• night operation,
• weekends,
• plant holidays.

The normal production flow may, for example, be

1.500 Nm³/h

.

At night, by contrast, only

60 Nm³/h

may remain.

These 60 Nm³/h

may partly result from:

• leaks,
• open blow-off nozzles,
• valve leakage,
• consumers that remain in operation

.

An excessively large measuring range

can reduce resolution in the lower range.

Therefore

during sizing:

Qmin

and:

Qmax

should be determined realistically.

Standardizing standard volume and reference conditions

Compressed air consumption is often specified as standard volume.

The indicated value

Nm³/h

does not simply refer to the geometric volume of the compressed air within the pipe.

Instead

the gas quantity is converted to defined reference conditions or, depending on the measuring principle, output as standard volumetric flow.

It is important

that different measuring points within the plant use the same reference conditions.

Otherwise

1.000 Nm³

at measuring point A cannot be directly compared with:

1.000 Nm³

at measuring point B if different reference conditions are configured.

With the IVA520

different reference conditions can be configured.

Therefore, during commissioning the following should be documented

• reference pressure,
• reference temperature,
• gas type used,
• unit used.

Particularly for energy management and cost-center allocation

All compressed air measuring points being compared should operate on the same defined reference basis.

Correctly planning inlet and outlet straight runs

Flow meters require suitable flow conditions.

Disturbances occur, for example, downstream of

• pipe bends,
• T-pieces,
• reducers,
• valves,
• control valves,
• filters.

These components can generate

• swirl,
• asymmetrical velocity profiles,
• turbulence

.

If the sensor is installed immediately downstream

the local flow profile may differ from the profile assumed for the measurement.

Therefore

the inlet and outlet conditions specified for the respective:

• sensor design,
• pipe size,
• upstream disturbance

must be observed.

Important

There is no universal inlet straight run that applies equally to every flow meter and every piping installation.

The specifications for the specific device are decisive.

Considering installation location and pipe condition

In addition to the flow direction, the mechanical conditions also play a role.

The following should be checked

• actual pipe internal diameter,
• nominal diameter,
• pipe material,
• corrosion and contamination,
• installation position,
• accessibility,
• operating pressure,
• gas temperature.

Especially with insertion sensors

the insertion depth must be set correctly.

An incorrect position of the sensing element

changes the locally measured flow velocity and can therefore cause a systematic error.

For large pipes

the actual internal diameter should therefore be known rather than using only the nominal DN value.

Distinguishing dry and wet compressed air

The measuring principle must match the condition of the compressed air.

Thermal consumption sensors

are particularly suitable for gaseous media without condensation on the sensing element.

A measuring point can be problematic

if:

• condensate is present,
• water droplets are entrained,
• the pipe regularly becomes wet.

For such applications

a correspondingly suitable measuring principle must be selected.

ICS offers, for example, the

IVD520 Inline Differential Pressure Flow Sensor

explicitly, among other applications, for:

wet compressed air

This illustrates

The question “ring main or branch line?” is only one selection criterion. The actual condition of the medium at the measuring point is equally important.

Detecting leaks using consumption measurements

One of the most important applications of compressed air meters is leak analysis.

Typical approach

The production area is observed outside regular operating hours.

Ideal condition

If all intended consumers are switched off, consumption should decrease significantly.

If, for example, a constant

Q = 120 Nm³/h

remains, it must be checked which consumers are causing this base consumption.

However, especially in a ring main

it must first be clarified whether these:

120 Nm³/h

are actually flowing into the area being investigated.

A ring section can also

supply compressed air to a neighboring area at night.

Therefore

for leak analysis, a clearly defined:

balance boundary

is more important than a single measured value somewhere in the ring.

Transmitting measured values to PLC, control system and energy management

For permanent consumption monitoring, measured values are often recorded centrally.

According to ICS, the IVA500 includes as standard

• 4 … 20 mA,
• pulse output,
• Modbus RTU via RS-485.

Depending on the version, the following are also available

• Modbus TCP,
• Ethernet,
• PoE,
• M-Bus.

For the IVA520

various analog and digital interface versions are also available.

Particularly important for ring mains

is not only the transmission of the flow magnitude.

The higher-level system should also know

• which flow direction is present,
• how positive and negative values are handled,
• which totalizer is being used.

For a clean balance

data point names should, for example, clearly distinguish between:

Flow Forward

Flow Reverse

Consumption Forward

Consumption Reverse

Net Consumption

Recommended planning and testing procedure for compressed air measurement in a ring main

1. Define the measurement objective: Specify total consumption, hall consumption, machine consumption, leakage or network balance.
2. Document the piping network: Record ring mains, branch lines, compressors and consumers.
3. Define the balance boundary: Specify which lines enter or leave the desired consumption zone.
4. Check possible flow directions: Determine for each measuring point whether reverse flow can occur.
5. Select the measuring point: Combine the clearest possible consumer assignment with suitable pipe conditions.
6. Check medium condition: Consider dry or wet compressed air, temperature, pressure and possible condensation.
7. Estimate Qmin and Qmax: Consider production peaks as well as nighttime and leakage flows.
8. Select the measuring principle: For dry compressed air, for example, use a thermal consumption sensor; for other conditions, evaluate appropriately suitable measuring principles.
9. Define bidirectionality: If flow reversal is possible, select an appropriate device configuration.
10. Define direction detection: If required, include IVA 409 or a suitable bidirectional measuring solution.
11. Check pipe dimensions: Determine the actual internal diameter and installation conditions.
12. Check inlet conditions: Consider bends, T-pieces, valves and reducers upstream of the measuring point.
13. Define installation position: Observe the manufacturer’s installation specifications.
14. Standardize reference conditions: Document reference temperature, reference pressure and gas type.
15. Define signal processing: Clearly define forward, reverse and net quantities.
16. Set up communication: Use analog signal, pulse, Modbus or another interface appropriate for the application.
17. Plausibility-check the measuring point: After commissioning, compare the current flow direction with the system operating state.
18. Check the consumption balance: Compare the sum of the sub-consumers with the main measurement.
19. Analyze nighttime consumption: Evaluate base load and possible leakage flows.
20. Store trends: Compare consumption across shifts, days and production conditions.
21. Plan calibration: Include recurring verification or recalibration in the maintenance schedule.

Typical errors in compressed air measurement in ring mains

Observation	Possible cause	Recommended check
Consumption of a hall appears negative at times	Flow direction in the ring has changed	Check flow direction and balance boundary
Flow value is correct, but consumption balance is not	Measuring point also records a neighboring network section	Check piping network and consumer assignment
Totalized consumption is unusually high	Forward and reverse flow are both added positively	Check totalizer configuration
Main meter indicates less than the sum of the sub-meters	Different reference conditions or measuring-point errors	Check standard conditions, gas type and installation
Flow changes significantly after a consumer elsewhere is switched on	Load distribution within the ring shifts	Analyze measuring direction and pressure distribution
Nighttime consumption is unexpectedly high	Leaks or supply to other ring sections	Check balance boundaries and operating conditions
Sensor shows unstable values immediately downstream of a pipe bend	Disturbed flow profile	Check installation position and required inlet straight run
Measured value no longer matches after piping modifications	Changed pipe geometry or flow distribution	Check internal diameter and measuring-point parameters
Thermal sensor provides implausible values when condensate occurs	Wet compressed air or liquid on the sensing element	Check medium condition and suitable measuring principle
Very small leakage flows are poorly resolved	Measuring range or pipe size too large	Reassess Qmin and measuring range
Reverse flow is not detected	Measuring system not designed for bidirectional detection	Check device version and direction detection

Practical example: balancing a production hall in a compressed air ring main

A production hall is supplied from a central compressed air ring main at two points.

Measurement objective

The operator wants to record the:

actual compressed air consumption of the hall

.

Initial approach

A consumption sensor is installed in the left-hand main ring line.

Problem

The flow measured there does not exclusively supply the hall.

Depending on the operating condition, part of the air continues to flow into the:

remaining ring

The measuring point is therefore unsuitable for hall consumption accounting

even though the sensor itself measures correctly.

Improved solution

The balance boundary is placed directly around the hall.

At connection A

the following is measured:

QA

At connection B

the following is measured:

QB

Both measuring points can change direction depending on the network situation

and are therefore evaluated according to direction.

Snapshot 1

QA = +480 Nm³/h

QB = +220 Nm³/h

Hall consumption

QHalle = 700 Nm³/h

Snapshot 2

After a change in the ring-main load:

QA = +520 Nm³/h

QB = -80 Nm³/h

The net inflow is then

QHalle = 520 − 80 = 440 Nm³/h

The negative flow at measuring point B

is not a measurement error.

It shows that part of the compressed air supplied through connection A is currently flowing back into the ring through connection B.

Result

Only the combination of suitable measuring-point selection and correct directional evaluation turns multiple flow values into a reliable consumption balance.

Suitable ICS products for compressed air ring mains

IVA500 – Consumption Sensor for Compressed Air and Gases

For consumption measurement in existing pipelines, ICS offers the:

IVA500

ICS specifies, among other things

• measurement of mass flow with direct output of standard volumetric flow,
• thermal mass-flow measuring principle,
• use for compressed air and various non-corrosive gases,
• 4 … 20 mA, pulse and Modbus RTU as standard,
• additional communication interfaces optionally available,
• integrated display,
• use from DN15 to DN1000, larger diameters on request,
• installation via ½” ball valve,
• optional bidirectional measurement.

Particularly important for ring mains

is the option:

bidirectional measurement

because the flow direction can change within a section of the ring.

IVA520 – Inline Flow and Consumption Sensor

For a defined inline measuring section, ICS offers the:

IVA520

.

The IVA520

measures mass flow and directly outputs the standard volumetric flow.

ICS specifies, among other things

• measurement of flow and consumption,
• thermal measuring principle,
• integrated measuring section,
• various measuring ranges,
• various reference standards,
• 4 … 20 mA,
• pulse output,
• Modbus RTU,
• additional interface variants,
• optional bidirectional measurement.

For a new installation

the integrated measuring section can help clearly define the mechanical installation of the consumption measurement.

IVA 409 – Direction Switch for Compressed Air and Gas Systems

Especially for ring mains, ICS offers the:

IVA 409

Its central task

is detection of the:

flow direction of compressed air and gases

ICS specifies

• special suitability for ring mains,
• detection of very small changes in flow direction,
• no mechanical wear parts,
• installation under pressure,
• potential-free contact for directional information.

Particularly relevant

is the combination described by ICS with:

IVA500 / IVA520

for clear detection of:

incoming and outgoing compressed air

in ring mains.

IVD520 – for Wet Compressed Air

If wet compressed air is expected at the intended measuring point, ICS also offers the:

IVD520 Inline Differential Pressure Flow Sensor

ICS explicitly lists the application

wet compressed air

The instrument provides

• flow rate,
• total consumption,
• temperature,
• pressure.

Which solution is suitable?

Task	Suitable ICS solution
Consumption measurement in an existing compressed air line	IVA500
Consumption measurement with a defined inline measuring section	IVA520
Bidirectional operation in a ring main	IVA500 or IVA520 in the corresponding bidirectional version
Separate detection of flow direction in a ring main	IVA 409
Measurement of incoming and outgoing compressed air in ring mains	IVA 409 in combination with IVA500 / IVA520 according to the measuring concept
Wet compressed air	IVD520 or evaluate a measuring principle suitable for the specific application

Additional solutions can be found under Flow Measurement Technology at ICS Schneider.

Conclusion

Compressed air measurement in a ring main is primarily a question of the:

correct balance boundary

and only then a question of the sensor.

A ring main can change its flow direction

Depending on consumers, compressors and pressure distribution, the same pipe can temporarily carry flow in both directions.

A single measuring point is therefore not automatically a consumption meter

The measured flow must be clearly assignable to the required:

• consumer,
• subnetwork,
• building,
• cost center

.

With reverse flow, the direction must be taken into account

For a net balance:

Inflow positive → Reverse flow negative

Bidirectional measurement can therefore be decisive

IVA500 and IVA520 are available from ICS with a corresponding bidirectional option.

For ring mains, the IVA 409 can additionally be used

to clearly detect the current flow direction.

The measuring point itself also determines measurement quality

Inlet conditions, pipe internal diameter, insertion depth, medium condition and reference conditions must match the measuring concept.

And finally

all meters within a balance must use the same definition of:

Standard volume + Flow direction + Totalization

.

For practical applications

Document the piping network → Define measurement objective → Define balance boundary → Identify all inflows and outflows → Check possible flow reversal → Select suitable measuring points → Determine Qmin and Qmax → Check compressed air condition → Select suitable measuring principle → If required, provide bidirectional measurement or IVA 409 → Check inlet conditions and pipe data → Configure uniform reference conditions → Clearly evaluate forward and reverse flow → Check totalizer → Test measuring points under different system operating conditions → Analyze nighttime consumption and leaks → Permanently document consumption trends.

FAQ: Correctly Measuring Compressed Air Consumption in a Ring Main

Why is flow measurement in a ring main difficult?

Because compressed air can flow through a network section in different directions depending on the current pressure and consumption situation.

Can the flow direction in a compressed air ring main actually reverse?

Yes. Changes in consumer load, compressor control or valve positions can change the pressure distribution and therefore the local flow direction.

What is the difference between flow rate and consumption?

Flow rate is the quantity of gas currently transported per unit of time. Consumption is the gas quantity integrated over a period of time.

How is compressed air consumption calculated?

In principle, the flow rate is integrated over time: V = ∫ Q(t) dt.

What does bidirectional flow measurement mean?

A bidirectional measuring system can detect flow in both possible directions or evaluate it according to direction.

When do I need bidirectional compressed air measurement?

When the flow direction at the measuring point can change and both directions are relevant for the consumption or network balance.

Do I also need bidirectional measurement in a branch line?

Not necessarily. If the flow is clearly directed from the ring toward the consumer by design and reverse flow is not possible, a correspondingly directional measurement is generally sufficient.

Where should a compressed air meter be installed?

Preferably where the desired consumer or balance area can be clearly defined and suitable flow and installation conditions are available at the same time.

Can I measure the consumption of a hall directly in the ring?

Only if the measuring point, or combination of several measuring points, actually records all inflows and outflows of the hall.

What does a balance boundary mean?

A balance boundary is an imaginary boundary around the area being analyzed. All compressed air lines crossing this boundary must be included in a complete balance.

How is a hall balance calculated with two compressed air connections?

The direction-dependent flow rates of both connections are added using their respective signs.

Can a negative flow value be correct?

Yes. At a bidirectional measuring point, a negative value can simply mean that the current flow is opposite to the defined positive direction.

Is reverse flow a fault in a compressed air network?

Not necessarily. In ring mains, a reversal of flow can be completely normal due to the current pressure distribution.

Why can a totalizer be misinterpreted in a ring main?

If forward and reverse quantities are not processed according to the measurement objective, the total transported quantity can, for example, be confused with the actual net consumption.

What is the difference between gross quantity and net quantity?

A gross evaluation can consider all transported quantities regardless of direction. The net quantity, by contrast, considers inflow and reverse flow with different signs.

Why is nighttime consumption important?

During production shutdowns, remaining flow rates can indicate leaks or unintentionally active consumers.

Can I detect leaks using a main meter?

A main meter can reveal an unusual base consumption. To locate the leak, further sub-metering or systematic leak detection is then required.

Why is the minimum flow important when selecting a device?

A measuring instrument must not only record production peaks but, where required, also sufficiently detect low nighttime and leakage flows.

What is standard volumetric flow?

Standard volumetric flow describes the gas quantity referenced to defined reference conditions for pressure and temperature.

Why must the reference conditions of all compressed air meters be the same?

Only then can consumption values from different measuring points be directly compared and balanced.

What are inlet straight runs?

Inlet straight runs are sufficiently long pipe sections upstream of the flow meter in which a flow profile suitable for measurement can develop.

Why are pipe bends upstream of the sensor problematic?

They can generate swirl and asymmetrical velocity profiles and thereby influence the flow measurement.

How long must the inlet straight run be?

This depends on the specific measuring instrument, pipe dimension and type of upstream disturbance. The manufacturer’s specifications for the respective sensor are decisive.

Why must the pipe internal diameter be known?

For certain flow measurement methods, it is required to calculate the volumetric flow or correctly configure the instrument.

Can I use a thermal consumption sensor with wet compressed air?

The specific suitability depends on the sensor and process conditions. Condensation on the thermal sensing element can be problematic. For wet compressed air, ICS offers suitable differential-pressure flow solutions such as the IVD520.

What is the IVA500?

The IVA500 is a consumption sensor listed by ICS for compressed air and various gases based on the thermal mass-flow measuring principle.

Can the IVA500 measure bidirectionally?

Yes. ICS lists optional bidirectional measurement for the IVA500.

For which pipe sizes is the IVA500 suitable?

ICS specifies use from DN15 to DN1000; larger diameters are available on request.

Which interfaces does the IVA500 have?

ICS specifies 4 … 20 mA, pulse output and Modbus RTU via RS-485 as standard, as well as additional optional interfaces.

What is the IVA520?

The IVA520 is an inline flow and consumption sensor with an integrated measuring section for compressed air and various gases.

Can the IVA520 measure bidirectionally?

Yes. A bidirectional version is provided for in the device data made available by ICS.

What is the IVA 409?

The IVA 409 is a direction switch for compressed air and gas systems that ICS specifically offers for detecting flow direction in ring mains.

Does the IVA 409 itself measure compressed air consumption?

Its primary task is to detect the flow direction. For actual consumption measurement, it is combined with suitable consumption sensors.

Can the IVA 409 be combined with IVA500 or IVA520?

Yes. ICS explicitly describes the combination for measuring incoming and outgoing compressed air in ring mains.

What is the IVD520?

The IVD520 is an inline differential-pressure flow sensor that ICS offers, among other applications, for wet compressed air and technical gases.

Which values does the IVD520 provide?

ICS specifies flow rate, total consumption, temperature and pressure.

Which measuring solution is most suitable for a compressed air ring main?

This depends on the measurement objective and installation conditions. If flow reversal is possible, a suitable bidirectional IVA500/IVA520 version or a measuring concept with IVA 409 is particularly relevant.

Where can I find the IVA500 at ICS Schneider?

Further information can be found under IVA500 Consumption Sensor at ICS Schneider.

Where can I find the IVA 409 at ICS Schneider?

Further information can be found under IVA 409 Direction Switch at ICS Schneider.

Where can I find the IVD520 at ICS Schneider?

Further information can be found under IVD520 Inline Differential Pressure Flow Sensor at ICS Schneider.

Where can I find additional compressed air consumption meters at ICS Schneider?

An overview can be found under Consumption Meters for Gases and Compressed Air at ICS Schneider.

Where can I find additional flow measurement instruments at ICS Schneider?

An overview can be found under Flow Measurement Technology at ICS Schneider.