Pneumatic drives
UKSPAR pneumatic actuators catalog
UKSPAR presents rotary pneumatic actuators Fig.1A single-acting and Fig.2A double-acting. They are designed for automation of quarter-turn valves — ball valves and disc valves — provided that the flange, stem and torque are compatible.
The pneumatic actuator for valves can be supplied as a basic actuator or complete with a solenoid valve, positioner and limit switch block. The composition is determined by the functions of the system, not the buyer's love for the word "complete set".
How to choose a pneumatic actuator for your valves
The calculation is performed based on the maximum moment of the valve at the minimum guaranteed air pressure. For spring versions, the moment is checked both at the working and spring stroke. The recommended margin is added and seal aging, deposits and cycle frequency are taken into account. Also important when selecting:
- valve type, DN, PN and required torque;
- minimum and maximum compressed air pressure;
- rotation angle, flange and stem fit;
- safe position in case of loss of air;
- temperature, IP, corrosion and explosion protection of accessories.
The latch requires a compatible linear or multi-turn actuator or a special mechanism.
The principle of operation of a pneumatic actuator
Compressed air moves the pistons, and a rack and pinion or rocker mechanism turns the output shaft. Through an adapter, it rotates the valve or gate stem 90°. The speed is regulated by the air flow, and the extreme positions are controlled by mechanical stops and signaling devices.
A pneumatic actuator for a crane must produce sufficient breakaway torque after standstill. Exhaust throttles help to avoid too sharp a turn, but do not compensate for an incorrectly sized actuator.
Single and double action
In a double-acting actuator, air is supplied alternately to two cavities: it performs both opening and closing. In a single-acting actuator, air moves the mechanism in one direction, and springs return it when pressure is lost.
Compatibility of pneumatic actuators with valves, cocks and gates
For ball valve and the valve check ISO 5211 or other specified interface, stem square and direction of rotation. The standard specifies the connection dimensions and reference torques, but the adapter must be rigid and coaxial.
For gate valves and shut-off valves, a linear or multi-turn pneumatic mechanism is required. If the motion doesn't match, the adapter won't convert a quarter turn into dozens of turns—at least without a separate gear that no one noticed in the specification for some reason.
Equipment: solenoid valve, positioner, limit switches
The solenoid valve controls the supply and exhaust of air by an electrical signal. The NAMUR interface allows compatible models to be installed directly, without additional tubing, saving installation time and reducing the risk of leaks.
Limit switches record and transmit to the dispatching system the discrete state of the drive - "open" or "closed".
The positioner provides precise control: it compares the set signal with the actual position of the stem and sets intermediate positions, which is critically important for control valves.
If necessary, the kit is supplemented with a filter-regulator, pressure gauges, throttles and an emergency valve - this increases the reliability and service life of the drive. It is important that the air quality meets the manufacturer's requirements: water, grease and mechanical impurities accelerate the wear of seals and reduce the service life of the equipment.
Buy a pneumatic actuator with delivery across Ukraine
To quickly select and purchase a pneumatic actuator, send us:
- armature model;
- required torque;
- working air pressure;
- safe position (NO/NC);
- list of necessary signals.
UKSPAR will promptly prepare a commercial offer for a basic or fully equipped version according to your technical requirements.
Our manager will help you choose the optimal product, check availability in stock, and arrange delivery for you across Ukraine.