The basic characteristics of the vacuum valve having high airtightness (sealing reliable); resistance to airflow as small as possible (i.e., the conductance valve as large as possible); a sealing member wear resistance, can be used repeatedly, and long life; Valve materials and seals outgas small; easy to clean install flexible operation and reliable performance, easy maintenance in addition. For ultra-high vacuum valves can also require high temperature baking (450 ℃); on the throttle can even adjust the gas flow requirements.
Common vacuum valve body materials are mainly metal and glass. Manual vacuum valve actuator handwheel made of high strength plastic material. Glass vacuum piston known as “Hancock”, generally used in glass vacuum system, a small vacuum, vacuum gauge to regulate or the calibration system. The advantage is relatively easy to make, easy to use, easy to clean observed chemical stability and good insulation. Deflated, although less so on. The downside is that because of the fragility of glass and curved mouth pistons coated with a layer of fat, so limit its use of vacuum equipment needed in industrial production such as vacuum coating equipment, vacuum smelting equipment, vacuum heat treatment equipment, space environment simulation equipment, rocket engine simulation equipment, satellite surface charged analog devices, particle accelerators and controlled nuclear fusion device, heavy particle accelerator, adopted metal valves.
Vacuum valve is usually based on the operating characteristics of the valve, transmission principle, control and controlled nuclear fusion equipment, heavy particle accelerator, adopted metal valves.
Connection and use of the classification, can be divided into the following categories:
① according to the working pressure: low vacuum valves, high vacuum stuffy door, ultra-high vacuum valve;
② according to use: cut-off valves, isolation valves, charge (discharge) valve, throttle, valve, closing the feed valve.
③ According transmission principle: a manual valve, flashlight dual valves, solenoid valves, pneumatic valves, hydraulic vacuum valve;
④ according to the material: glass vacuum piston (Hancock), metal vacuum valve;
⑤ according to structural characteristics: a flapper valve, flap valves, operated valves, ball valves, connecting rods valves, septum valve, gate valve, two-way valve, three-way valve, four-way valves, globe valves, right angle valve.