Digital Series 500 MFM's & Series 600 MFC's offer ± 0.8% of reading plus ± 0.2% full scale accuracy & linearity with ± 0.2% of rate repeatability. A majority of the analog Series 100 MFM's or Series 200 MFC's have ±1% full scale accuracy & linearity with ± 0.2% full scale repeatability.

Digital MFM's/MFC's allow a user to store in memory as many as eight (8) calibration curves. If using our Series 100 MFM's or Series 200 MFC's, the correction for any additional gases must be done manually or programmed in the secondary electronics.

Digital control circuitry reduces 'dead time' when ramping from zero flow conditions. LED operation indicators confirm proper operation of the digital control circuitry.

Digital MFM's/MFC's have many parameter settings for signal processing, controlling, etc.

The digital series MFM's/MFC's offer Modbus, 0-5 Vdc, 0-10 Vdc & 4-20 mAdc (sourcing) output signals. The analog series MFM's/MFC's offer 0-5 Vdc, 0-10 Vdc, 1-5 Vdc, 4-20 mAdc (sourcing) & 4-20 mAdc (sinking) output signals.

First, determine whether a MFM or MFC is required for the application. Define the gas, flow range & desired type of output signal, allowing the basic model to be selected. To complete the model number, define the type of PC board electrical connector (if not already defined by the type of output signal), elastomer material, process fitting size & type & any special features.

Our 'typical' lead time is 3-4 weeks after receipt of order. Often times, this can be improved. Tell us your required in-house date & we will do whatever we can to accommodate your request.

Define the gas type, operating temperature, upstream (supply) pressure, downstream (outlet) pressure (downstream pressure required for MFC's only), calibration standard & are any additional accessories (e.g. interconnecting cable assemblies, secondary electronics, etc.) required.

Calibration standard is the standard reference temperature used when expressing a gas volume or a volumetric flow rate & must be defined because gas volume varies with the temperature & pressure of the gas. The calibration standard temperature should not be confused with the process operating temperature.

Common calibration standards are 0°C (32°F), 20°C (68°F), 21.1°C (70°F) & 25°C (77°F). Lesser known calibration standards are 15°C (59°F) & 15.6°C (60°F).

The standard pressure is 14.7 PSIA & does not require definition. Although less common standard pressure values exist (e.g. 100 kPa, 101.325 kPa, 14.503 PSIA, 14.696 PSIA, 14.73 PSIA), 14.7 PSIA is employed as the standard pressure at Porter Instrument.

A basic MFM/MFC system consists of a MFM/MFC, power supply, digital indicator/totalizer/batch counter, a setpoint signal source (required for MFC's only) & an interconnecting cable assembly. Multi-channel secondary electronics packages incorporating a power supply, a digital indicator & command potentiometers (setpoint signal sources) are available as an option to supplying the required components individually. Other more sophisticated secondary electronics packages (e.g. programmable logic controllers, etc.) may also be coupled with a MFM/MFC. Various types & lengths of interconnecting cable assemblies are available.

Yes, however there are limitations. Sizing a MFM involves the thermodynamic properties of the process gas. To correct from the gas for which the unit was originally calibrated to another gas involves a simple mathematical correction. This is the only sizing required for a MFM. Using our Digital Series 500 MFM's or Series 600 MFC's allows a user to store in memory as many as eight (8) calibration curves. If using our Series 100 MFM's or Series 200 MFC's, the correction for the second gas must be done manually or programmed in the secondary electronics.

Sizing a MFC is more involved & involves two (2) sizings. The first sizing involves the flow meter portion of the MFC as explained above for a MFM. The second sizing is for the control valve, which contains a fixed orifice, an orifice of a fixed size. The orifice size is calculated based on gas density, flow range, inlet pressure & outlet pressure. Changing any one of these four parameters will affect your orifice size, & possibly, affect the control valve's operation. Without actually trying the second gas at the desired operating parameters, it is often difficult to predict how an MFC will control a second gas.

Compare the MFM/MFC specifications with those of the secondary electronics to determine compatibility. If using an MFC, confirm the power supply's current rating is sufficient to power the MFC. The most commonly encountered problem is not connecting the commons. The circuit common & valve common should be connected at the common of the power supply.

The gas type, inlet pressure & outlet pressure all determine the lowest obtainable flow range. It is best to contact the factory to have the application sized.

A Variable Area Flow Meter is a flow measuring device that operates on the principle of allowing fluid flow to pass around a float housed in a tapered tube. As flow force increases (normally from higher flow rates), the float moves up the tapered tube to allow for more flow area around the float. The measured flow rate then corresponds to the location of the float within the tube.

See attached Formula factor sheets (not on line at this time)

The full scale of a flow Meter would be the maximum flow range indicated on the scale of a specific tube and float combination.

Example: A flow meter with an advertized accuracy of +/- 5% FSA and a maximum flow range of 1000 sccm Air would have a accuracy of +/- 50 sccm Air at any point of flow between 100% to 10% of the maximum flow.

Our 'typical' lead time is 3-4 weeks after receipt of order. Often times, this can be improved. Tell us your required in-house date & we will do whatever we can to accommodate your request.

High number of parts variations economically prohibits the stocking of completed flow meters.

No, Porter mechanical regulators are Non-Relieving.

No.

These regulators do not control properly when used in a vacuum application.

No. There is not enough surface area available for NPT ports that are larger than 1/8" NPT.

No. The valve seat is available in Viton only.

Excessive force used to achieve positive shut-off can deform or score the sealing surface in the valve. Porter Standard Cartridge Valves are available with the exclusive Torque Guard Stop Mechanism. The Torque Guard eliminates stem damage caused by over tightening of the valve at shut-off.