A pneumatic actuator converts energy (typically in the form of compressed air) into mechanical motion. The motion can be rotary or linear, depending on the type of actuator. Some types of pneumatic actuators include:
- Tie rod cylinders
- Rotary actuators
- Rodless actuators with magnetic linkage or rotary cylinders
- Rodless actuators with mechanical linkage
- Pneumatic artificial muscles
- Speciality actuators that combine rotary and linear motion—frequently used for clamping operations
- Vacuum generators
A Pneumatic actuator mainly consists of a piston, a cylinder, and valves or ports. The piston is covered by a diaphragm, or seal, which keeps the air in the upper portion of the cylinder, allowing air pressure to force the diaphragm downward, moving the piston underneath, which in turn moves the valve stem, which is linked to the internal parts of the actuator. Pneumatic actuators may only have one spot for a signal input, top or bottom, depending on action required. Valves require little pressure to operate and usually double or triple the input force. The larger the size of the piston, the larger the output pressure can be. Having a larger piston can also be good if air supply is low, allowing the same forces with less input. These pressures are large enough to crush objects in the pipe. On 100 kPa input, you could lift a small car (upwards of 1, 000 lbs) easily, and this is only a basic, small pneumatic valve. However, the resulting forces required of the stem would be too great and cause the valve stem to fail.
This pressure is transferred to the valve stem, which is hooked up to either the valve plug (see plug valve), butterfly valve etc. Larger forces are required in high pressure or high flow pipelines to allow the valve to overcome these forces, and allow it to move the valves moving parts to control the material flowing inside.
Valves input pressure is the "control signal." This can come from a variety of measuring devices, and each different pressure is a different set point for a valve. A typical standard signal is 20–100 kPa. For example, a valve could be controlling the pressure in a vessel which has a constant out-flow, and a varied in-flow (varied by the actuator and valve). A pressure transmitter will monitor the pressure in the vessel and transmit a signal from 20–100 kPa. 20 kPa means there is no pressure, 100 kPa means there is full range pressure (can be varied by the transmiters calibration points). As the pressure rises in the vessel, the output of the transmitter rises, this increase in pressure is sent to the valve, which causes the valve to stroke downard, and start closing the valve, decreasing flow into the vessel, reducing the pressure in the vessel as excess pressure is evacuated through the out flow. This is called a direct acting process.
Siemens 656-0019 2-Way Angle Union Valve with Pneumatic Actuator and 5 to 10 psi Spring Range, 1/2-Inch
Home Improvement (Siemens)
Partial sterling combustion engine design2008-08-28 18:29:38 by wuzawuzzal
The main idea is to have the cylinders charge and detonate fuel in an computer controlled automated way as to reduce the amount of combustion cycles that would other wise be necessary to keep the engine running.
The piston is directly connected to a pneumatic actuator that extends and retracts to either draw in fresh fuel or expel exhaust gases. A charge is loaded and valves are operated pneumatically to open a path to the drive train or to exhaust spent fuel. A pressure relief valve is installed to prevent over pressure and also to direct excess cylinder pressure to a pressure tank (not shown) to be used to power actuators
Keltron receives order worth Rs 2.44 crore — The New Indian Express
The pneumatic actuators will be manufactured at the Keltron Controls division of Keltron at Aroor in Alappuzha district.
Semiconductor Processing Improves with FPGA-based Controller — Automation World
The machine includes a rotary mechanism with pneumatic actuators to handle freshly diced wafers, which are identified by a gigabit Ethernet camera to position the stage to pick components of the freshly cut silicon with actuators.
Angle-seat Valve 1" NPT with Pneumatic Actuator
Hydraulics and Pneumatics, Third Edition: A technician's and engineer's guide
Jardin Plastic Aquarium Fish Tank One Way Air Check Valves, 2-Piece, Clear Black
Pet Products (Dragonmarts Co. Ltd. / Uxcell)
Amico JM-06A 13mm Thread 3/2 Way Red Flat Push Button Pneumatic Mechanical Valve
Home Improvement (Amico)