Compared with other valve driving devices, electric driving devices have the characteristics of wide power source, fast and convenient operation, and can easily meet various control requirements. Therefore, among valve driving devices, electric devices dominate.
◆Valve electric devices are divided into two types according to the input mode: multi-turn type (Z type) and partial rotation type (Q type). The former is used for lift rod valves, including: gate valves, globe valves, throttle valves, diaphragm valves, etc.; The latter is used for rotary rod valves, including ball valves, plug valves, butterfly valves, etc., which usually open and close within the 900 range.
Valve electric devices are divided into two categories: ordinary type and special protection type according to the type of protection.
◆The usage environment of ordinary electric devices is as follows:
1. Ambient temperature: -25~40℃
2. Environmental relative temperature ≤90% (at 25℃)
3. Altitude ≤1000m
4. The working environment requires no corrosive, flammable or explosive media.
◆If the working environment conditions of the valve exceed the capabilities of ordinary electric devices, special protective products need to be used. Such products come in various types depending on the working environment.
Main technical features of special protective electric devices
Type Main features
Outdoor type 1. Ambient temperature: -40~40℃
2. Maximum rainfall: 50mm/10min
3. Maximum solar radiation intensity: 1.4J/(cm2·min)
4. There is sand, snow, frost, and dew
High temperature type, the maximum ambient temperature can reach 80℃
Low temperature type, the lowest ambient temperature can reach -55℃
Anti-corrosion type: There is one or more environments containing a certain concentration of chemically corrosive media.
High-speed type valve stem rotation speed reaches 70r/min
Explosion-proof type should be able to work in an environment with explosive media
Ship type: Suitable for environments where sea water or salt spray exists on ships
Fire-resistant type should be able to open or close normally within a certain period of time (such as 15 minutes) in an environment where a fire occurs (such as a temperature of 1300°C).
Two-speed type, two-speed change range up to 60:1
Diving type Water-resistant type I is suitable for short-term immersion working environment (10mm, 72h); water-resistant type II is suitable for long-term immersion working environment, the water depth can be greater than 10m
Radiation protection type suitable for occasions with special requirements of nuclear power plants