Brand: Rotork

Rotork Fairchild Model 55 Miniature Precision Regulator

Name: Rotork Fairchild Model 55 Miniature Regulator – Datasheet & Quote
Brand: Rotork
SKU: Fairchild Model 55

Description

The Rotork Fairchild Model 55 is a miniature precision regulator built from polymer rather than metal. It is the smallest and lightest regulator in the Fairchild range covered here, intended for instrument air, analyzer sample systems and equipment where weight, space or corrosive surroundings rule out an aluminum or brass body. Rotork lists high accuracy for precision control, handling of supply pressures up to 150 psig, and a manifold-mount option for compact assemblies.

Polymer body, stainless valve

The body and housing are Valox 508, which resists the corrosion that attacks metal bodies in washdown, chemical or coastal atmospheres. The valve is stainless steel and the diaphragm is polymer reinforced nitrile. A venturi design compensates downstream pressure droop under flow, and a separate control chamber isolates the diaphragm from the main flow to eliminate hunting and buzzing. The adjustment knob is non-rising, so it does not extend when the setpoint is increased, and a tamper proof actuator is available.

Technical specifications

Parameter	Specification
Model	Fairchild Model 55 miniature precision regulator (catalog number begins 551)
Maximum supply pressure	150 psig (10 bar)
Flow capacity	9 SCFM (17.0 m3/hr) at 120 psig (8 bar) supply
Exhaust capacity	2 SCFM (3.4 m3/hr) at 15 psig (1.0 bar) above the setpoint
Supply pressure effect	0.1 psig for a 10 psig change in supply
Pressure ranges	0-10, 0.5-30, 1-60 and 2-100 psi
Ports	1/8 inch NPTF, or manifold mount
Ambient temperature	-40 to +150 degF (-40 to +65.5 degC)
Body and housing	Valox 508
Valve	Stainless steel
Diaphragm	Polymer reinforced nitrile
Mounting bracket	Valox 508 (optional)

How to build a Model 55 catalog number

The ordering section of the datasheet starts from the base number 551 and adds one character for each choice. Range codes are 2 (0-10 psi), 3 (0.5-30 psi), 4 (1-60 psi) and 5 (2-100 psi). The port code is 0 for manifold mount or 1 for 1/8 inch, followed by the thread letter N for NPTF and the elastomer letter N for nitrile. The remaining choices are:

Actuator: K for knob, T for tamper proof
Relief: R relieving with normal bleed, N non-relieving, B relieving with low bleed
Gauge: G with gauge, N without
Mounting: B with mounting bracket, N without

Choosing the relief type matters. A non-relieving unit cannot vent excess downstream pressure, so it needs a continuous downstream flow to regulate properly, while a relieving unit exhausts the surplus through its vent.

Application notes and points to confirm

Because the maximum supply is 150 psig, the Model 55 is not a drop-in for a 250 psig or 500 psig header; a metal regulator such as the Model 30 or Model 10 is the usual route there. Confirm the range, relief type, whether a gauge is required, and that the ambient temperature stays inside the stated limit, which is lower than for the metal-bodied models. Installation and maintenance are described in Fairchild instruction IS-10000055.

Documents and quotation

The Rotork datasheet is attached. Send Seven Star LLC the catalog number or your range, port, relief and gauge needs, and we will prepare a quotation from our regulators range. For a no-bleed alternative in aluminum, see the Rotork Fairchild Model 1000.

Datasheets & Documents

Datasheet Rotork Fairchild Model 55 Miniature Precision Regulator Datasheet Download

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About brand

Electric valve actuators are what most engineers picture when they hear the name Rotork, a company founded in 1957 and based in Bath, United Kingdom. Its catalog also reaches into pneumatic and hydraulic actuators, control valve actuators and instrument-air accessories.

Seven Star LLC lists Rotork actuators, positioners and precision regulators and supplies them to operators and valve shops in Oman, with the actuator build checked against the manufacturer's documentation.

Rotork product families on this page

The IQ3 is the intelligent multi-turn electric actuator for gate, globe and sluice valves, and the IQT3 is its part-turn counterpart for ball, butterfly and plug valves. For control valves there are the CVA and CMA electric actuators, built for continuous modulating duty. The Skilmatic SI3 is a self-contained electro-hydraulic actuator used where a fail-safe stroke is required. On the fluid power side the page lists GP/GH scotch yoke pneumatic and hydraulic actuators and the CP compact pneumatic quarter-turn unit. Two instrument brands sold under the Rotork name complete the list: Fairchild, with the Model 1000 no-bleed precision regulator, and YTC, with the YT-1000 electro-pneumatic and YT-3300 smart positioners.

Where Rotork actuators are used

Typical duties are isolation and block valves on pipelines and tank farms, motor-operated valves in refineries and power plants, sluice gates and large butterfly valves in water and wastewater works, and emergency shutdown valves on oil and gas facilities across the GCC.

Ordering Rotork actuators and parts: what we need

For an existing unit, send the serial number and the wiring diagram number from the nameplate; these two identify the exact build. For a new selection we need the valve type and size, torque or thrust, stem or shaft details, operating time, supply voltage, phase and frequency, the hazardous area certification, and any bus or remote control option. For pneumatic units add the air supply pressure and the fail position.

Browse Rotork products by category: Valve Positioner, Valve Actuator.