Measurement Equipments

Flow Meter

Know exactly how much air your plant uses, and how much it loses, in true standard cubic metres, whatever your line pressure.

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A thermal mass flow meter with its display head on a flanged stainless steel measuring section

Product overview

See where every cubic metre of your air goes

Our thermal mass flow meter measures the flow of your compressed air or technical gas by the heat the moving gas carries away from a heated sensor. That heat depends on the mass of gas passing, so the meter reads mass flow directly and reports it as standard volume flow, in m³/h, m³/min or l/s, with no separate pressure or temperature measurement.

The sensor sits inside your pipe, usually at the centreline, and the meter turns that point reading into flow through the whole pipe from its bore and the shape of the velocity profile. It totalises your consumption, and with your compressors’ electrical energy gives the specific energy of your air in kWh per standard m³.

Thermal sensors respond to low gas velocities, so one meter records both full production demand and the small flow left when every consumer is switched off: the leakage rate of your network.

A thermal mass insertion flow probe with its display head
  • Mass flowRead directly, no pressure or temperature inputs
  • ISO 1217Or DIN 1343 reference conditions
  • No moving partsNothing in the flow to wear or jam
  • Under pressureProbes fit through a ball valve

Benefits

Measured air, managed cost

Compressed air is one of the most expensive utilities in your plant, and most networks were installed without a flow meter. Here is what that hides, and what measurement shows.

  • Leaks you can cost

    The problem

    Leaks are spread over hundreds of fittings, hoses and valves, many can’t be heard over production, and energy guidance cites 20–30 % of compressor output lost in poorly maintained systems.

    How it solves it

    Read your main header with production stopped and the flow you see is your leakage rate, ready to cost, target and check again after repair.

  • Steady readings as pressure swings

    The problem

    Air at 7 bar g takes about one-eighth of its free air volume, and every change in pressure or temperature changes that ratio.

    How it solves it

    The meter responds to mass, so its reading stays in standard units at any line pressure and gas temperature within its rating.

  • Compressors sized to real demand

    The problem

    Nameplate totals overstate demand, because machines rarely all run at full consumption at the same time.

    How it solves it

    A flow profile shows your true peak, base load and the storage needed to cover short peaks, before you add or replace a compressor.

  • Fair cost allocation

    The problem

    A single compressor energy bill hides which area actually drives demand.

    How it solves it

    Branch meters charge each department, product line or tenant for its own consumption.

  • Evidence for ISO 50001

    The problem

    ISO 50001 energy management and ISO 11011:2013 assessments rest on measured demand, not estimates.

    How it solves it

    Totalised consumption and flow profiles, logged alongside compressor power, give your specific energy in kWh per standard m³.

  • Faults flagged early

    The problem

    A burst hose, a stuck drain or a blow-off valve left open wastes air unseen.

    How it solves it

    Alarm thresholds flag flow that rises above the expected level for the time of day.

Where it’s used

Wherever air is a cost worth knowing

From a single machine supply to the main header leaving your compressor room, flow data turns air into a figure you can manage.

  • Robots welding a car body on an assembly line

    Automotive and engineering

    Branch metering allocates air cost to paint shops, body shops, machining and assembly lines.

  • Wine bottles moving along a bottling line

    Food and beverage

    Bottle blowing, pneumatic conveying and packaging lines, where air is a major utility cost.

  • Yellow tablets spilling from a medicine bottle

    Pharmaceuticals

    Measured consumption of tablet coating, fluid-bed and filling equipment supports validation and utility records.

  • A row of yarn winding machines in a textile mill

    Textiles

    Air-jet looms draw large, continuous flows, and per-loom or per-shed metering tracks their consumption.

  • Glowing glass bottles being formed on a production machine

    Glass, cement and steel

    Headers supplying burners, conveying and instrument air, metered for cost allocation and demand planning.

  • Test tubes of coloured chemicals in a laboratory rack

    Industrial gases

    Gas-specific calibrations measure carbon dioxide, argon, oxygen and nitrogen supplied to welding, beverage carbonation and process users.

Also energy audits and leak surveys, clean dry air and nitrogen in electronics, nitrogen generator outlets, compressed air billed as a utility service, and commissioning checks on compressor delivery and dryer purge consumption.

How it works

Heat carried away, read as mass

A heated sensor loses heat to the air flowing past it. The more mass flows, the more power it takes to keep the sensor warm, and that power is the measurement.

How a thermal mass flow meter works: an insertion probe sits at the pipe centreline on a straight run. In its sensor window an unheated reference element takes the gas temperature, and a heated element is held a fixed amount warmer by a control loop. The more mass of air flows past, the more heat it carries away and the more power the loop supplies; the meter turns that power into standard volume flow and adds it up over time. at least 15 D upstream5 D downstream 511 m³/h Day 12,264 m³ Dry compressed air Ball valveInsertion probe Transmitter Reference: gas temperature Heated: gas + fixed ΔTPower P = I² · R 12345Dry compressed airAir velocity across the pipeHeat carried away by the air

  1. 1. Place the probeThe probe goes in through a ball valve to the pipe centreline, aligned with the flow, on a straight run of at least 15 pipe diameters upstream and 5 downstream, so the velocity profile is fully developed.

  2. 2. Sense the gas temperatureAn unheated platinum reference element takes on the temperature of the gas flowing past it.

  3. 3. Hold the heated elementA control loop holds a second platinum element a fixed amount above the gas temperature. More gas flowing past carries more heat away, and the loop raises the heating current until the difference is restored. The power it needs is the measurement.

  4. 4. Convert to standard flowThe calibration curve turns heating power into mass flux, and the meter applies the profile factor and your pipe’s actual bore. At 8 m/s in a 53.1 mm bore at 7 bar g and 20 °C it reads 511 m³/h, and if the pressure falls to 6 bar g with the same mass flowing, it still reads 511 m³/h.

  5. 5. TotaliseThe meter adds the flow up over time, in the same reference conditions as the reading. At 511 m³/h, one 24-hour day adds 12,264 m³ to the totaliser.

Example figures for air at 8 m/s in a pipe with a 53.1 mm bore, at 7 bar g and 20 °C, referred to ISO 1217 conditions.

Get the full details

Our brochure covers it in detail, and our questionnaire tells us what we need to recommend the right one for your plant.

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