Model 22 Pneumatic Computing Relay from Rotork Fairchild

Model 22 Pneumatic Computing Relay from Rotork FairchildModel 22 Pneumatic Computing Relay is a highly versatile control valve designed to perform a number of specialized functions, including averaging, differential, inverting, and totalizing. This high-quality unit, which offers up to four inputs as well as positive and negative biasing over a broad range, is available in several configurations to meet most application requirements.

If you need a reliable, flexible pneumatic relay that can combine multiple control signals, apply biasing or scaling, and provide stable, precise output control, the Model 22 from Rotork is an excellent choice. Its wide operating range, versatile configuration options, and robust construction make it a solid backbone component for complex process-control systems — particularly where pneumatic signal processing is required before final actuation or further control logic.

Features

Model 22 Pneumatic Computing Relay Features

  • Ideal choice in a variety of applications with specific input/output requirements such as override or multi-element control, or as an ON-OFF valve
  • When used as an ON-OFF valve, the Model 22 may open or close a pneumatic circuit, moving rapidly to a full open or a full closed position when signal pressures deviate from set pointIn the full open position, the valve passes full supply pressure without modulation or regulation. The function is achieved by connecting output pressure to the signal chamber. This connection forms a feedback loop so that, once flow is started, the valve is driven wide open. The relay always goes full open or full closed when conditions are as shown in the diagrams on the Rotork Fairchild specification sheets and catalogue
  • Small bleed across relief seat assures fast response to even very small signals
  • Multiple inputs available - allows versatility in process control applications
  • Adjustable bias range from -18 to +15 psig permits variation in output to meet your needs
  • Two gauge ports located 90° from supply and outlet ports - versatility in installation in your equipment
  • Line or panel mounting - quick and easy installation in the field

Specifications

Model 22 Pneumatic Computing Relay Specifications

CategorySpecification
Input and Output Pressure3–15 psig (0.2–1.0 bar), (20-100 kPa)
Normal Supply20 psig (1.5 bar) (150 kPa)
Maximum Supply Pressure150 psig (10 bar)
Maximum Signal Pressure50 psig (3.5 bar)
Maximum Output Pressure50 psig (3.5 bar)
Output Linearity±0.4% of full scale
Repeatability±0.5% of full range
Air Consumption0.06 SCFM (0.102 m3/hr) at 15 psig output (dead-end service)
Bleed TypeSmall bleed across relief seat for sensitive response
Operating Temperature Range–40°F to +200°F (–40°C to +93.3°C)
Materials – Body & BonnetDie-cast aluminum
Material – DiaphragmBuna-A
Material – Fasteners/Range ScrewsZinc-plated steel
Gauge PortsTwo ports located 90° from supply/output
Mounting OptionsLine or panel mounting
Functions SupportedAveraging, differential, inverting, amplifying, totalizing, ON/OFF switching, and other pneumatic computing modes
Number of InputsUp to 4 signal inputs

Applications

Model 22 Pneumatic Computing Relay Application

The flexibility of the Model 22 makes it suitable for a wide range of control and automation tasks, including:

  • Multi-element or override control loops (e.g. combining signals from several sensors for a “master” output)
  • Differential or averaging signal computation (e.g. temperature or pressure differential monitoring)
  • Amplifying or scaling low-level pneumatic signals for downstream control valves or instrumentation
  • ON/OFF pneumatic switching where a simple relay or actuator is needed, based on processed input signals
  • Totalizing inputs (sum of multiple pressure signals) for feed-forward control, load balancing, or other process-management schemes

Q & A

Q&A Section with Expand/Collapse Icons

Model 22 Pneumatic Computing Relay Q & A

+What is the purpose of the Model 22 computing relay?
The Model 22 is a pneumatic control relay designed to combine, process, or modify multiple pneumatic input signals (up to 4 inputs) and produce a controlled pneumatic output. It can perform operations like averaging, differential, inverting, totalizing, biasing, or ON/OFF switching.
+How many input signals can it accept, and what functions are supported?
It supports up to four inputs, and can be configured for functions such as averaging, differential, inverting, totalizing (sum), amplifying or scaling, positive/negative biasing, master-override or multi-element control, or simple ON/OFF relay behavior.
+What are the normal operating pressure ranges (input, output, supply)?
Normal input (and output) signal range is 3–15 psig (0.2–1.0 bar). Nominal supply pressure is 20 psig (1.5 bar). Maximum operating pressure for signal/output is 50 psig (3.5 bar), and maximum supply pressure is 150 psig (≈10 bar).
+How accurate and stable is the output?
Output pressure linearity is within ±0.4% of full scale. Repeatability (under normal input range) is within ±0.5% of full range. Also, changes in supply pressure (e.g., ± 5 psig) do not significantly affect output.
+What are the installation and mounting options?
The relay includes two gauge ports oriented 90° from the supply and outlet ports for flexible piping or instrumentation. It supports both line-mounting and panel-mounting configurations.

Downloads

Download Rotork Fairchild Model 22 Pneumatic Computing Relay Datasheet

Contact us at (855) 737-4714 to learn more or fill out our online form.

 
You were tireless in your support and it will not be forgotten!
 
When we needed technical assistance and application support, Valin was there for us. Their knowledgeable engineers saved us an invaluable amount of time, helping us get up and running quickly. We are very happy with their services.