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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
Air Consumption
- < 0.1 scfm (0.17 m³/hour)
Ambient Temperature Range
- -40° to 93.3° C (-40° to 200° F)
BSP Connection
- 1/4” BSPT Female
- 1/8” BSPT Female
- 3/8” BSPT Female
Diaphragm Material
- Buna-N & Dacron
Enclosure, Body Material
- Aluminum
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
Exhaust Port
- Tapped Exhaust
Flow Capacity
- 14 scfm (23.8 m³/hour)
Mounting
- Bonnet Mounting
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
Signal or Output Pressure - Maximum
- psig: 150 (kPa: 1,000, bar: 10)
Standard Features
- Tamper-Proof
Supply Pressure
- psig: 150 (kPa: 1,000, bar: 10) Recommended Operating Supply Pressure
Supply Pressure - Maximum
- bar: 17.5
- kPa: 1,750
- psig: 250
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
Trim Material
- Aluminum
- Brass
- Stainless Steel
