Gate valve is a slide type valve. It is mainly used as a cut-off medium in the pipeline, that is, full or closed use. Generally cannot be used as throttling.

    Gate valves can be used for high temperature and high pressure, and can be used in a variety of different media, but generally not used for conveying mud, viscous fluid in the pipeline.

    Gate valve is generally used in the size of the valve is not strict requirements, but also the use of harsh conditions, such as high temperature and pressure of the working medium, the requirements of closed parts to ensure long-term seals.

    The main advantage of the gate valve is that when the valve is fully opened, the medium in the pipe can be passed in a straight line, so the fluid resistance through the valve is small. Usually, the use of conditions or requirements of good sealing performance, high pressure, high pressure cut-off (pressure differential), low pressure cut-off (small pressure), low sound absorption, cavitation and vaporization of the phenomenon, High-temperature Medium, low-temperature (deep cold) when the recommended use of gate valve, in the mud medium, to the air leakage of the occasion can be selected, in the throttling, regulation, wear and tear,

    Open and close action quickly, short control, abrasive medium as far as possible not to choose the gate valve, in the opening and closing frequency of high occasions can not choose the gate valve. In addition, in the installation space is small, suitable for large diameter valves and installation of space restrictions on the pipeline, such as underground pipelines, suitable for the selection of open and close without changing the height of the dark stem gate valve. However, this type of valve must be fitted with an opening and closing indicator to show the valve open.

    The disadvantage of this kind of dark rod type gate valve is that the stem thread is contacted with the medium directly, and it is easy to be corroded by the medium. In the gate valve there is also a structure, that is, the valve body's channel diameter is different, the valve seat sealing surface of the smaller diameter, flange connection of larger diameter, known as necking gate valve. This gate valve structure small weight light, but the flow resistance is large, suitable for convection resistance requirements LAX pipe, general steam and water pipeline on more. The valve due to its diameter shrinkage, so that the size of the parts to reduce the torque required to open and close the corresponding reduction. However, the loss of fluid resistance increases with the shrinkage of the path. In order to minimize the fluid resistance loss in the medium flow necking, the diversion ring device can be used.

    Necking Gate valves are not allowed on the pipeline of petroleum systems. In petroleum, chemical systems, especially in oil, natural gas long-distance pipeline, suitable for the use of floating valve seat plate type gate valve. This type of flat gate valve has a guide hole and no diversion hole.

    The flat gate valve with the guide hole is mainly used for oil and gas pipelines to clean the pipelines, especially for large, high parameters and automatic piping, and the flat gate valve without the guide hole is suitable for all kinds of pipe-opening and closing devices. In all valves, the most slow opening and closing action is the valve. During the opening and closing process, the gate's moving distance is greater than the valve's channel diameter ·, moreover, the gate valve total height is high, occupies the space position to be big, also more bulky. However, from a mechanical point of view, it is relatively free, so it is suitable for use in water conservancy facilities.