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Brand: Biffi
Biffi RPD Double-Acting Pneumatic Rack and Pinion Actuator
Description
Overview
The Biffi RPD is a double-acting pneumatic quarter-turn actuator of rack and pinion design. The manufacturer describes the RPD and its spring-return counterpart, the RPS, as actuators for on-off and modulating control of valves in heavy duty service, designed to give maximum torque output with minimum supply pressure. The RPD is intended for any quarter-turn application such as ball, plug and butterfly valves or dampers, and the series is available for output torques up to 3700 Nm.
The RPD is powered by a compressed gas supply. It is not an electric or electro-hydraulic unit and it has no motor, pump or oil reservoir. The supply medium can be air, nitrogen or sweet gas, and the design pressure (maximum allowable working pressure) is 12 barg maximum. Seven Star LLC supplies the Biffi RPD on request to buyers in Oman and the GCC, with lead time confirmed at quotation.
Operating Principle of the Biffi RPD
In the RPD a pneumatic piston moves inside a cylinder mounted on the side of the actuator housing. The piston is connected to a rack, and the rack meshes with a pinion on the output shaft. When supply gas is admitted to one side of the piston, the rack moves and turns the pinion and the valve stem through 90°. Admitting gas to the opposite side of the piston drives the actuator back.
A rack and pinion mechanism has a constant lever arm, so the output torque is constant throughout the 90° stroke. The torque depends on the actuator model, the cylinder version and the operating supply pressure. The datasheet torque table lists values from 72 Nm for model 15-D1 at 3 barg up to more than 3400 Nm for the largest 120 models. Each model has its own maximum operating pressure (MOP), between 5 and 12 barg.
Engineering Design of the Biffi RPD
The housing is weatherproof and totally enclosed. On the double-acting RPD it is made of carbon steel. The shaft is nickel-plated alloy steel, the rack and pinion are ductile iron, and an adjustable bronze sliding block supports the rack to keep transverse forces low. The cylinder tube is carbon steel with an electroless nickel-plated, polished bore for corrosion resistance and low friction. Piston and shaft seals are NBR rubber as standard, with fluoroelastomer and fluorosilicone seals available as an option.
Travel stop screws at each end allow angular stroke adjustment of 90° plus or minus 4° at each end of travel. The RPD is offered in actuator models 15, 30, 60 and 120, each with cylinder versions D1 and D2, and model 120 also with versions D2.4 and D3. A jackscrew manual override (MHW) can be fitted, and both actuator flanges can be used for valve coupling or for mounting ancillary equipment such as a positioner or limit switch box.
Key Features
The following features are stated by the manufacturer for the RPD and RPS series.
- Weatherproof, totally enclosed fabricated carbon steel housing.
- Constant output torque throughout the 90° stroke.
- Adjustable bronze sliding block that keeps transverse forces low.
- Nitrided rack for minimal friction.
- Angular stroke adjustment of 90° plus or minus 4° at each end of travel.
- Electroless nickel-plated polished cylinder for corrosion resistance and minimal friction.
- Floating-type piston seals with low hysteresis and high sensitivity, which prevent sticking.
- Lever or jackscrew manual override, an extensive range of accessories, and special coatings for offshore or corrosive environments.
Industrial Applications
The Biffi RPD is used to automate quarter-turn valves and dampers where a pneumatic supply is available and the valve should be driven in both directions by that supply. Typical duties are on-off isolation and modulating control of ball, plug and butterfly valves in process plants, utilities and pipeline installations.
The series carries approvals that matter for hazardous and outdoor locations. The datasheet lists ATEX area classification II 2 GD, enclosure ratings IP66, IP66M and IP67M to IEC 60529 and NEMA 4, 4X and 6, and suitability for use in SIL 3 applications to IEC 61508. For coastal or offshore sites, special coatings and stainless steel mounting brackets and tie rods are available as options. Where the valve must move to a safe position on loss of supply, the spring-return Biffi RPS is the corresponding model.
Technical Specifications
The table below summarizes the main data for the Biffi RPD, taken from Biffi product data sheet VCTDS-02813-EN Rev. 4 (June 2023).
| Parameter | Specification |
|---|---|
| Model | Biffi RPD (double-acting pneumatic) |
| Actuator Type | Pneumatic rack and pinion, quarter-turn (90°) |
| Supply Medium | Air, nitrogen or sweet gas |
| Design Pressure (MAWP) | 12 barg maximum |
| Maximum Operating Pressure | 5 to 12 barg, depending on model |
| Output Torque | Up to 3700 Nm (series) |
| Standard Temperature Range | −20°C to +100°C |
| Extended Temperature Range | −60°C to +135°C |
| Stroke Adjustment | 90° ± 4° at each end of travel |
| Models | 15, 30, 60, 120 with cylinder versions D1, D2, D2.4, D3 |
| Enclosure Protection | IP66, IP66M, IP67M; NEMA 4, 4X, 6 |
| Approvals | ATEX II 2 GD; suitable for SIL 3 applications (IEC 61508); PED 2014/68/EU; Machinery Directive 2006/42/EC |
| Manual Override | Lever or jackscrew (MHW), optional |
| Valve Compatibility | Ball, plug and butterfly valves, dampers |
Request a Quote for Biffi RPD Double-Acting Pneumatic Rack and Pinion Actuator
To request a quote for the Biffi RPD, send Seven Star LLC the valve type and size, the required torque with safety factor, the available supply pressure and medium, the ambient temperature range and any accessories needed, such as a manual override, positioner or limit switch box. The actuator is supplied on request, with lead time confirmed at quotation.
Browse the full Biffi range or see more Valve Actuator products supplied by Seven Star LLC in Oman and the GCC.
Datasheets & Documents
- Datasheet Biffi RPD / RPS Pneumatic Actuators Datasheet Download
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About brand
Biffi is an Italian maker of valve actuators for the oil and gas and petrochemical industries. Its first factory opened in 1955 in Fiorenzuola d'Arda, near Piacenza, making electric actuators for the Italian petrochemical industry; the company moved to its present site in 1969. Biffi is now part of Emerson, and its pneumatic, hydraulic and electric actuators drive pipeline, wellhead and shutdown valves.
Seven Star LLC lists Biffi actuators across these operating media and supplies them to valve automation shops and operators in Oman, sized from the valve torque data.
Biffi company profile
| Founded | 1955, Fiorenzuola d'Arda, Italy |
|---|---|
| First products | Electric valve actuators for the Italian petrochemical industry |
| Headquarters | Fiorenzuola d'Arda, Piacenza, Italy (Biffi Italia Srl) |
| Ownership | Emerson |
| Product families | ALGA pneumatic scotch-yoke actuators, ALGAS gas-over-oil actuators, F01 and ICON2000 electric actuators, electro-hydraulic and hydraulic actuators for on-off and emergency shutdown duty |
Milestones
- 1955: The first Biffi factory opens in Fiorenzuola d'Arda.
- 1969: Biffi moves to its present location.
- 1978 and 1996: The plant is expanded.
Biffi actuator series on this page
The series names follow a logic that helps when reading a tag. ALGA is the pneumatic quarter-turn actuator and ALGAS its spring-return version. OLGA-H is the hydraulic quarter-turn actuator and OLGAS-H the fail-safe hydraulic version with spring. In the compact rack-and-pinion group, RPD and RPS are the double-acting and spring-return pneumatic pair, and RPHD and RPHS are their hydraulic counterparts. The F01 and F02 are electric quarter-turn actuators, the ICON2000 and ICON3000 are electric multi-turn actuators and the EFS 3000 is a fail-safe electric quarter-turn actuator; the manufacturer now names the Bettis SCE300 as the replacement for the F02. In each pair the S marks the model that returns to a safe position by spring.
Where Biffi actuators are used
Typical duties are emergency shutdown and blowdown valves, pipeline block valves, wellhead and manifold valves, tank farm isolation and large ball valves at compressor and metering stations. Spring-return models are chosen for fail-safe service. Hydraulic and electro-hydraulic units appear where instrument air is not on hand, as on remote GCC pipeline stations.
Biffi products we list
Ordering Biffi actuators: what we need
Actuators are sized, so the valve data comes first: valve type and size, the torque curve or at least break, run and end torques, the safety factor in your specification and the stem and mounting flange dimensions. Then the supply: minimum and maximum air or oil pressure, or voltage for electric units. State the fail action, stroking time, ambient temperature and the control accessories required. For an existing actuator send the model and serial number from the nameplate.
Facts checked against Biffi's own history (Emerson), October 2026.
Browse Biffi products by category: Valve Actuator.
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Frequently Asked Questions
What type of actuator is the Biffi RPD?
The Biffi RPD is a double-acting pneumatic quarter-turn actuator of rack and pinion design. A pneumatic piston drives a rack, which turns a pinion on the output shaft through 90 degrees. It is used for on-off and modulating control of ball, plug and butterfly valves and dampers. It is not an electric or electro-hydraulic actuator.
What supply does the RPD require?
The RPD is operated by a compressed gas supply. The manufacturer datasheet lists air, nitrogen or sweet gas as the supply medium, with a design pressure of 12 barg maximum. Each model also has its own maximum operating pressure, between 5 and 12 barg, which must not be exceeded. No electrical power is needed for the actuator itself.
What torque does the Biffi RPD deliver?
The RPD and RPS series covers output torques up to 3700 Nm. The datasheet torque table for the RPD starts at 72 Nm for model 15-D1 at 3 barg supply pressure. Torque depends on the actuator model, the cylinder version and the supply pressure, and it is constant throughout the 90 degree stroke.
What happens to the RPD if the air supply is lost?
The RPD is double-acting, so both the opening and the closing stroke are powered by the supply. It has no spring, and it does not move to a defined safe position by itself when the supply fails. Where a spring-driven fail action is required, the spring-return Biffi RPS from the same series is used. A lever or jackscrew manual override is available.
How does Seven Star LLC supply the Biffi RPD?
Seven Star LLC supplies the Biffi RPD on request to buyers in Oman and the GCC. Lead time is confirmed at quotation. To prepare a quote we need the valve type and size, the required torque, the available supply pressure and medium, the ambient temperature range and any accessories such as a manual override or limit switch box.
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