Vacuum valve: refers to the standard operating pressure lower than atmospheric pressure vacuum valve. Vacuum valve connected in the form of several common

　　1. flange

　　This is the most commonly used, combine to form the valve. By combining the surface shape can be divided into the following categories:

　　1) Smooth: valve for the pressure is not high. convenient processing.

　　2) Bump-style: pressure is really high, you can use the hard disk.

　　3) pin slot: a large plastic deformation of the seal is used in corrosive media more extensive and better sealing.

　　4) trapezoidal trough: oval metal ring seal for use in the operating pressure of ≥ 64 kg / square centimeter of the valve or valves to high temperatures.

　　5) Lens Type: Washing machine is lens-shaped, with metal production. For operating pressure ≥ 100 kg / cm high pressure valves and high temperature valves.

　　6) O-ring type: This is a relatively new form of the flange, it is displayed with a variety of rubber O-ring, and developed it in a sealed effect, washers and more reliable than the average.

　　2.threaded connection

　　This is a simple connection system, commonly used in small valve. Was divided into two cases:

　　1) Direct Seal: The seal directly on the inner and outer threads. To ensure that leakage is not the connections that often result in oil lines Ma and Teflon tape filled; become including Teflon tape, more common, good corrosion resistance of the material seal poles well, easy to use, and preservation, demolition, you can be completely removed because it is not sticky layer of film is more than lead oil, hemp is far superior line.

　　2) Indirect sealing: thread tightened the power supplied to the seal between the two levels, so that the seal.