Rotork Fairchild Model 10BP Precision Back Pressure Regulator

The Rotork Fairchild Model 10BP is a precision back pressure regulator: instead of reducing a supply, it relieves excess pressure from a pneumatic system and holds the upstream pressure at a chosen setpoint. Rotork positions it as a high capacity unit that gives greater accuracy than a relief valve over a narrow pressure range, with a control sensitivity of less than 1/8 inch water column. It is the back pressure companion to the Model 10 pressure reducing regulator and uses the same family of ranges and ports.

How back pressure control works

System pressure is carried through the aspirator tube to the underside of the diaphragm assembly. The range screw compresses a positive bias spring that pushes on the top of the assembly. While the pressure force is below the spring force, the relief valve stays closed. When system pressure exceeds the setpoint, the assembly moves up, lifts the relief valve off its seat and vents air until pressure falls back; as it drops below the setpoint the valve closes again. A separate control chamber and the aspirator tube isolate the diaphragm from the main flow to eliminate hunting and buzzing, and the unit can be serviced without removing it from the line.

Technical specifications

Options and ordering

The catalog number is built from 102BP, a range digit (1 for 0-2 psig up to 9 for 5-400 psig, with 0 for 0-20 psig) and a pipe size digit (2, 3 or 4). Option letters on the datasheet are:

• A silicone elastomers, J fluorocarbon (Viton) elastomers
• H BSPP parallel threads (inlet and outlet ports only, others BSPT) or U BSPT tapered
• S screwdriver adjust or T tamper proof

A mounting bracket kit, 09921, is sold separately, and installation instructions are in Fairchild document IS-100010BP.

Where to use it and what to confirm

Typical uses are holding pressure in a pneumatic header, relieving a closed volume to a precise limit, and setting a back pressure on a process line that carries clean air or gas. Confirm that you need back pressure control rather than pressure reduction: connection and flow direction differ from a reducing regulator, and a safety relief valve is still required wherever a code or overpressure scenario demands one, because this device is a control regulator. Check the setpoint, maximum system pressure, thread and elastomer, and the flow the vent must pass.

How the Fairchild Model 10BP works

The regulator is fitted so that it senses the pressure of the system it protects. That pressure pushes up on a diaphragm. A spring above the diaphragm, set with the range screw, pushes down. While the system pressure is lower than the spring force, a relief valve stays shut. When the pressure rises above the setpoint, the diaphragm lifts the valve and air vents out until the pressure falls back.

Where the Fairchild Model 10BP is used

• Pneumatic systems that must hold a set pressure
• Vessels and lines that need a fine relief setpoint
• Instrument and process air
• Machine tools and test rigs
• Systems that need more accuracy than a relief valve

Selection checklist for the Fairchild Model 10BP

• Setpoint range
• Maximum system pressure
• Flow capacity needed
• Pipe size of 1/4, 3/8 or 1/2 inch
• Ambient temperature
• Silicone or standard elastomer
• Catalog number digits
• Mounting and gauge port

Installation, commissioning and maintenance notes for the Fairchild Model 10BP

Fit the regulator on the line so that the vent is clear and the flow follows the arrow. Turn the range screw slowly to set the pressure while you watch a gauge. Do not exceed the stated system pressure. The regulator can be serviced without removing it from the line, so keep a spare kit for planned shutdowns.

Requesting a quotation for the Fairchild Model 10BP

Please send the catalog number, the setpoint range, the pipe size and the quantity. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

Fairchild Model 10BP flow capacity

Flow capacity is 40 SCFM at 100 psig.

Fairchild Model 10BP sensitivity

Control sensitivity is below 1/8 inch of water column.

Fairchild Model 10BP pressure ranges

Ranges run from 0-2 psig up to 5-400 psig across nine spans.

Fairchild Model 10BP pipe sizes

Ports are 1/4, 3/8 or 1/2 inch NPT.

Fairchild Model 10BP temperature

Ambient temperature runs from minus 40 to plus 93 degrees C.

Fairchild Model 10BP materials

The body is aluminium and the trim is zinc plated steel and brass.

Fairchild Model 10BP hunting control

A control chamber and an aspirator tube isolate the diaphragm from the main flow to avoid hunting and buzzing.

Regulator records for the Fairchild Model 10BP

Record the catalog number, the setpoint and the date of each service.

Choosing the right Fairchild Model 10BP range

Choose a range with the setpoint in the middle of the span, for the best control.

Documents and quotation

The Rotork datasheet for the Model 10BP is attached. Send Seven Star LLC the catalog number or the setpoint, system pressure, port and thread, and we will prepare a quotation from our regulators range. For pressure reduction see the Rotork Fairchild Model 1000.