Images are representations only.
Model 85D Multi-Stage Positive Bias Relay
Brand: Fairchild Industrial ProductsThe Rotork Fairchild Model 85D Multi-Stage Biasing Relay is a precision control combining the sensitivity of a precision pressure regulator with positive biasing capability.
This compact, pilot-operated device offers unusually high output capacity with minimal air consumption, while providing excellent protection against supply or output pressure variations.
The versatile Model 85D is recommended for use in systems requiring precision pressure maintenance and instrument biasing, in dead end service and instrument panel supply applications.
The basic mathematical expression for the Fairchild Model 85D is PO = PS + K where PO is output pressure, PS is signal pressure and K is the spring constant.
Features- Two Stage Pilot Operation
- 14 SCFM flow capacity in a small size unit
- Low air consumption
- Compact size
- Available in 1/8", 1/4" and 3/8" standard port sizes
Specifications
Pressure Range
- 0-20 psig : 0-1.5 bar : 0-150 kPa
- 1-60 psig : 0.1-4 bar : 10-400 kPa
- 1-100 psig : 0.07-7 bar : 7-700 kPa
Pipe/Port Size
- 1/8"
- 1/4"
- 3/8"
Pipe/Port Thread Type
- NPT
- BSPT
Max. Supply Pressure
- 250 psig : 17.0 bar : 1700 kPa
Flow Capacity
- 14 scfm (23.8 m³/hr) @ 100 psig : 7.0 bar : 700 kPa supply, 20 psig : 1.5 bar : 150 kPa setpoint.
Supply Pressure Effect
- Less than 0.2 psig, : 0.014 bar : 0.14 kPa for 100 psig : 7.0 bar : 700 kPa change in supply pressure.
Exhaust Capacity
- 2.5 scfm (4.25 m³/hr) where downstream pressure is 5 psig : 0.35 bar : 35 kPa above 20 psig setpoint.
Max. Signal or Output Pressure
- 150 psig : 10 bar : 1000 kPa
Ambient Temperature Limits
- -40° F to +200° F (-40° C to 93.3° C)
Tapped Exhaust Vent
- Tapped
Tamper Proof
- Tamper Proof
Air Consumption
- Less than 0.1 scfm (1.7 m³/hr)
Body & Housing Material
- Aluminum
Diaphragm Material
- Buna-N on Dacron
Trim Material
- Aluminum, Brass, Stainless Steel
Mounting Style
- Line/Pipe Mount
- Bonnet Mount
Signal or Output Pressure - Maximum
- psig: 150 (kPa: 1,000, bar: 10)
Ambient Temperature Range
- -40° to 93.3° C (-40° to 200° F)
Supply Pressure
- psig: 150 (kPa: 1,000, bar: 10) Recommended Operating Supply Pressure
Standard Features
- Tamper-Proof
Air Consumption
- < 0.1 scfm (0.17 m³/hour)
Exhaust Port
- Tapped Exhaust
Supply Pressure Effect
- Less than psig: 0.2 (bar: 0.0014, kPa: 1.4) for psig: 100 (bar: 7, kPa: 700) Change in Supply Pressure
NPT Connection
- 1/4" NPT Female
- 1/8" NPT Female
- 3/8" NPT Female
Pressure Range
- bar: 0 to 7
- kPa: 0 to 700
- psig: 0 to 100
Diaphragm Material
- Buna-N & Dacron
Flow Capacity
- 14 scfm (23.8 m³/hour)
Enclosure, Body Material
- Aluminum
Trim Material
- Aluminum
- Brass
- Stainless Steel
Exhaust Capacity - Relieving Units Only
- 2.5 scfm (4.25 m³/hour) where Downstream Pressure is 5 psig (bar: 0.35, kPa: 35) Above Set Point
BSP Connection
- 1/4" BSPT Female
- 1/8" BSPT Female
- 3/8" BSPT Female
Mounting
- Bonnet Mounting
Supply Pressure - Maximum
- bar: 17.5
- kPa: 1,750
- psig: 250