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Model 25 Reversing Relay
Brand: Fairchild Industrial Products
The Rotork Fairchild Model 25 Reversing Relay is designed for applications requiring an output that equals a manually preset spring load minus a variable signal pressure.
This high quality unit combines excellent sensitivity with unusually high flow capacity.
The Model 25 is ideally suited for a variety of precision control applications, including converting direct acting valves to reverse action, controlling opposite acting valves from a single transmitter, and cushioning cylinder loads.
The basic mathematical expression for the Model 25 is PO = K - PS where PO is output pressure, PS is signal pressure and K is the spring constant.
Features- Control Sensitivity of 1/8" water column
- Balanced supply valve
- Aspirator tube design
- Separate control chamber isolates
- Unit construction
- Allows for use in high precision applications
- Minimizes the effects of supply pressure variation
- Compensates for output pressure droop under flow conditions
- Isolates the diaphragm from the main flow to eliminate hunting and buzzing
- Allows servicing without removal from air line
Specifications
Pressure Range
- 0-10 psig : 0-0.7 bar : 0-70 kPa
- 0.5-30 psig : 0.03-2 bar : 3-200 kPa
- 1-60 psig : 0.1-4 bar : 10-400 kPa
- 2-150 psig : 0.1-10 bar : 15-1000 kPa
Pipe/Port Size
- 1/4"
- 3/8"
- 1/2"
Pipe/Port Thread Type
- NPT
- BSPP
- BSPT
Max. Supply Pressure
- 250 psig : 17.0 bar : 1700 kPa
Flow Capacity
- 40 scfm (68 m³/hr) @ 100 psig, 7.0 bar, 700 kPa supply & 20 psig, 1.5 bar, (150 kPa) setpoint.
Supply Pressure Effect
- Less than 0.1 psig : 0.007 bar : 0.7 kPa for a 100 psig : 7.0 bar : 700 kPa change in supply pressure.
Exhaust Capacity
- 11 scfm (18.7 m³/hr) where downstream pressure is 5 psig : 0.35 bar : 35 kPa above setpoint.
Max. Signal or Output Pressure
- 150 psig : 10 bar : 1000 kPa
Sensitivity
- 1/8" W.C. : 0.31 mbar : 0.031 kPa
Ambient Temperature Limits
- -40° F to +200° F (-40° C to 93.3° C)
Tapped Exhaust Vent
- Tapped
Body & Housing Material
- Aluminum
Elastomers Material
- Viton (Fluorocarbon)
Diaphragm Material
- Buna-N on Dacron
Trim Material
- Aluminum, Brass, Stainless Steel
Mounting Style
- Line/Pipe Mount
- Panel Mount
Actuator Type
- Knob Adjust
BSP Connection
- BSPP Female (Parallel)
- BSPT Female (Tapered)
Supply Pressure Effect
- psig: 0.1 (bar: 0.007, kPa: 0.7) for a psig: 100 (bar: 7, kPa: 700) Change in Supply Pressure
Exhaust Capacity - Relieving Units Only
- 11 scfm (18.7 m³/hour)
Relief
- Relieving
NPT Connection
- 1/2" NPT Female
- 1/4" NPT Female
- 3/8" NPT Female
Sensitivity
- < 1/8 inH₂O (0.32 cm)
Enclosure, Body Material
- Aluminum
Elastomers
- Buna-N on Dacron
- Fluorocarbon (Viton)
Supply Pressure - Maximum
- bar: 17
- kPa: 1,700
- psig: 250
Ambient Temperature Range
- -40° to 93° C (-40° to 200° F)
Mounting
- Panel Mount
- Pipe
Pressure Range
- bar: 0 to 0.7
- bar: 0.03 to 2
- bar: 0.1 to 4
- bar: 0.15 to 10
- kPa: 0 to 70
- kPa: 10 to 400
- kPa: 15 to 1,000
- kPa: 3 to 200
- psi: 0.5 to 30
- psig: 1 to 60
- psig: 2 to 150
Vent
- Straight
- Tapped Exhaust
Flow Capacity
- 40 scfm (68 m³/hour)
Signal or Output Pressure - Maximum
- bar: 10
- kPa: 1,000
- psig: 150
