BIFFI RPS Spring return pneumatic actuators

Actuator Description

The RPS actuator features a pneumatic low pressure spring return and is suitable for any angular stroke rotary application such as shutting off and regulating ball, plug, butterfly or vibration dampened valves in heavy duty service. 

The actuator consists of a rack and pinion mechanism that drives the linear motion of the pneumatic cylinder in one direction and converts the linear motion of the spring into rotary motion for valve operation in the opposite direction. An adjustable bronze slide supports the lateral force applied to the rack by engaging with the pinion gear. The rack is nitrided to ensure minimum friction. 

The spring module contains one spring or two springs in series depending on the model and is fully encapsulated, which ensures personnel safety and easy assembly. External travel limit bolts allow precise angular travel adjustment between 80° and 100°.

The fully enclosed protective housing is made of ductile iron for maximum strength and is suitable for use in harsh environments.

The mounting flanges are identical on both (top and bottom) sides of the housing; the shaft output actuators have the same dimensions but are positioned at 90°. This allows the actuator to be used as a closing or opening spring without modification.

The actuator is assembled to the valve by connecting the actuator housing flange to the valve flange with a sleeve and, using the stem extension shaft, connecting the actuator shaft bore to the stem.

Rotate the jacking bolt with a hand lever or handwheel (available on request) to perform a manual emergency operation of the actuator in opposition to the spring action. 

The mounting flange on the top of the housing can be used to assemble limit switches, position sensors, positioners, etc. driven by the actuator output shaft.

Technical data

Supply medium: Air, nitrogen or desulphurisation gas

Operating temperature: Standard: -30°C to +100°C

                 Optional: -60°C to +140°C

Design pressure: up to 12 bar

Supply pressure: see technical data sheet  

Output torque: up to 3700 Nm

Installation

Inspection after receipt of the actuator

- Check that the actuator type, serial number and technical data reported on the nameplate correspond to the order confirmation.

- Check that the actuator is equipped with the accessories included in the order confirmation.

- Check that the actuator has not been damaged during transport: If necessary, repair the coating according to the specifications in the order confirmation.

- If the actuator is received assembled with the valve, it has been set up ex works.

- If the actuator is supplied separately from the valve, check and, if necessary, adjust the setting of the mechanical limit bolts and the setting of the position switches (if any).

Storage

If the actuator needs to be stored for a certain period of time before installation, perform the following steps before installation.

 - Place it on a wooden base to avoid damage to the valve coupling area.

- Ensure that there are plastic plugs on the pneumatic and electrical connections (if any).

- Check that the lids of the control assembly and limit switch box (if present) are properly closed.

If stored outdoors for extended periods of time.

 - Protect the actuator from changes in weather conditions.

- Replace the plastic plugs in the pneumatic and electrical connections (if any) with metal plugs to ensure perfect sealing.

- Apply oil and grease to the valve plate and valve coupling areas to maintain lubrication.

- Operate the actuator regularly