Pneumatic valve

Pneumatic control valves come in cylinder-type versions; these cylinder-type pneumatic valves can be used as on-off valves, or they can be used as control valves when paired with a positioner.

There are those of the cylinder type, whose opening can be controlled by a control circuit, such as the anti-surge control valves in large centrifugal compressors.

Pneumatic control valves come in cylinder-type versions. Cylindrical control valves are generally butterfly valves and ball valves with angular stroke.

The regulating function is determined not by the cylinder, but by the presence of a positioner. Where there is a positioner, there is a regulating function; without a positioner, it can only function as a on/off valve. There are two types of pneumatic valves: one type is single-acting, with a spring on one side and a cylinder on the other; the other type is double-acting, with cylinders on both sides.

The original poster might have confused the concepts; a control valve and a valve with regulatory functions are different things. For example, there are pneumatic control valves, as well as pneumatic control ball valves and pneumatic control butterfly valves. The valve element in pneumatic control valves is of the plunger type, so the actuator used is also of the straight-stroke type; typically, diaphragm actuators are chosen for this purpose. Due to their design, such valves serve only for regulation purposes and not for shutting off flow. Therefore, shut-off valves such as ball valves or gate valves are usually installed before and after these valves. When it’s necessary to stop the flow of the medium, simply close the ball valve or gate valve. Pneumatic control ball valves and pneumatic control butterfly valves have valve bodies that are actually ball valves or butterfly valves, but they are equipped with positioners, which allow for rough adjustment of the medium’s temperature, pressure, or flow rate. These control valves can be used both for regulation and for shutting off flow, but their flow characteristics and regulation accuracy are much inferior to those of pneumatic control valves. If the requirements for regulation performance at the site are not high, then pneumatic control ball valves can be used.

It would be better to turn what you said into a tree diagram – that way it’s easier to remember!

After creating the tree diagram, I noticed a problem. I would like to ask: for pneumatic control ball valves and butterfly valves, are the cylinders of angular stroke type, right? Is the valve spool of a pneumatic control valve of plunger type and is the cylinder of straight-stroke type? !

Cylinder types are very common and are widely used for adjustment purposes; butterfly valves, ball valves, and eccentric rotary valves are all typically equipped with cylinders

Cylinders also have a straight stroke; what matters primarily is the position of the cylinder, and it is the direction in which force is applied that is key