Pneumatic control valve, electric valve

I think what the book says about pneumatic valves being cheaper than electric valves mainly refers to chemical and oil refining plants that already have air supply stations； If there is no air station in the factory, building a separate air compressor station just for the pneumatic control valves represents a large investment ； Electric valves, on the other hand, only require power supply; they typically operate at 220V or 380V, and such power requirements are generally met ； In this case, electric valves are cheaper than pneumatic valves ； However, in terms of explosion protection rating, pneumatic control valves can achieve intrinsically safe performance, while electric valves can only achieve flameproof performance due to power supply constraints ；

A pneumatic valve is a valve that is driven by compressed air. In simple terms, an electric valve is one in which a electric actuator is used to control the valve, thereby enabling its opening and closing. It can be divided into two parts: the upper part is the electric actuator, and the lower part is the valve. 　　Electric valves come in two types: one is the angle-action electric valve, which uses an angle-action electric actuator in combination with an angle-action valve to enable control of the flow of fluid through the pipeline by rotating the valve by up to 90 degrees ； Another type is the straight-stroke electric valve: it consists of a straight-stroke electric actuator used in conjunction with a straight-stroke valve, to enable the valve disc to move up and down and thus control the flow of fluid in the pipeline. It is usually used in conjunction with highly automated equipment. Pneumatic valves require additional equipment for compressed air, resulting in high overall costs. It is thought that operation under high pressure results in a high failure rate. Electric valve equipment is easy to install, can be controlled from a distance, has low costs, and due to its simplicity, it has a very low failure rate. That’s why electric valves are widely used in factories these days.

For chemical plants, air compressor stations are part of the basic equipment

In some areas with high explosion-proof requirements, pneumatic valves must be used; in ordinary situations, electric valves are sufficient, as they can also provide explosion protection and isolation. These days, the price of many electric valves is not high either, so they can be chosen according to needs.

In fact, the cost of electric valves isn’t necessarily higher than that of pneumatic ones these days! Electric valves are simple to control.

Electric valves perform much better than pneumatic valves, as the air supply is prone to problems, especially in winter

Petrochemical enterprises use more pneumatic valves, while power plants use more electric valves. Pneumatic valves require a gas supply, so electric valves are the better choice in areas where no gas supply is available.