proportion-air faq


Flow Control

With our flow control/monitor products, we are subject to a 10:1 turn-down ratio (ask about potential 20:1 on low ranges). This means we will control well from 10% of the range to 100% of the range. Below 10% – our device will control flow, but the accuracy and repeatability becomes unpredictable.

The lowest range we can control:

  • 2 to 20 SCFH
  • 0.94 to 9.4 LPM
Category: Flow Control

With our flow control/monitor products, we are subject to a 10:1 turn-down ratio. This means we will control well from 10% of the range to 100% of the range. Below 10% – our device will control flow, but the accuracy and repeatability becomes unpredictable.

The highest range we can control:

  • 25 to 250 SCFM
  • 708 to 7,080 LPM
Category: Flow Control

Pressure Control

The specifications of all our products are based on the full calibrated range of the device.

For example: many products are rated for an accuracy of ±0.2% of Full Scale. If we were to calibrate one of these models 0-100 PSI, the accuracy of that unit would be ±0.2 PSI. If the same unit were calibrated 0-50 PSI, the accuracy would then be ±0.1 PSI.

With this in mind, the lowest pressure range we can calibrate to is:

  • 0 to 2 Inches of Water Column
  • 0 to 0.073 PSI
  • 0 to 4.98 mbar
  • 0 to 498 Pascal

Resolution is a measurement of the achievable pressure increments (steps) between the 0% calibrated point and 100% calibrated point.

For example: many products are rated for a resolution of ±0.02% of Full Scale. If we were to calibrate one of these models 0-100 PSI, the resolution of that unit would be ±0.02 PSI. If the same unit were calibrated 0-50 PSI, the resolution would then be ±0.01 PSI. This reflects the smallest pressure steps that can be achieved with this device.

With this in mind, the highest resolution we can achieve is with our QPV and MPV proportional pressure regulators. The resolution of each device depends on the application and orifice size used. Generally – the smaller the orifice the better the accuracy and resolution.

  • Typical Resolution = ±0.02%
  • Maximum Resolution = ±0.005%

Normally-closed, on/off valves are non-air consuming and designed for static applications where filing a volume and maintaining a specific pressure is required. When power is applied to these valves, they open fully until power is removed.

Proportional valves are constantly air consuming and need to be under constant flow for proper operation; these are designed for high resolution applications. The proportional valves are always slightly open during control operations. This allows for instant and small changes to downstream conditions.

We can control all noble gases (i.e. helium, neon, argon, krypton, xenon, radon), as well as air and nitrogen. We can also clean our units for oxygen use as well.

We have controlled other gases as well; please contact Proportion-Air for more information.

Yes, the ISQB is FM approved intrinsically safe (with approved barriers) and the ISF is FM approved Non-Incendive.

Here are the specific approvals for the ISQB:

  • Class I, II & III, Division 1, Groups C, D, E, F & G

Here are the specific approvals for the ISF:

  • Class I, II & III, Division 2, Groups C thru G T4; Type 4X hazardous (classified) locations and suitable for use in Class II, Division 2, Groups E, F and G T4


 

Call Us from Indianapolis : 317-689-0608

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