Gate Valve applications in the pipeline very broad, there are many classification gate. Gate valve according to the structure of the sealing surface divided into wedge gate-type valve and parallel gate-type valve types. Wedge gate-type valve can be divided into: single-gate type, double plate and the flexible gate formula and other three kinds of structure: single-gate structure is relatively simple, but high machining accuracy wedge angles, prone clamping, abrasions; double plate structure of the wedge angle accuracy is low, easy wedge gate dead, but the structure is more complex; both the advantages of flexible gate single gate and double plate, and to avoid their disadvantages, thus wider application. These structural features are on the periphery of gate valve shutter has a ring-shaped groove, the shutter having appropriate elasticity. Parallel gate-type valve can be divided into single-gate-type parallel double plate parallel to the valve and gate valve. Parallel gate valve usually double plate structure; valve for special purposes, such as long-distance oil and large diameter Gate valve on a gas pipeline with a cleaning required due to valves and pipelines and the use of a single gate structure.
According to the structure and movement of the Gate valve stem (threaded position) can be divided into two clear shot Gate valve gate and dark bar.
Gate valve with the valve stem linear movement, called the lift rod valve (also called clear shot valve). Often movements are trapezoidal threaded rod through the guide groove valve and the valve on top of the nut, and the rotary motion into linear motion, which is the operating torque thrust into action.
Open the valve, when the gate valve lift height equal to diameter of 1: 1 times, the fluid channel is completely smooth, but at run time, this position can not be monitored. Actual use, is the apex of stem as a sign that does not move the location, as its fully open position. Temperature appears to consider locking phenomenon, usually open to the vertex position, and then rewind 1 / 2-1 circle, as the location of a fully open valve. Accordingly, the fully open position of the valve, according to damper position (ie, travel> to determine. Some valve, the stem nut located at the gate, handwheel drive stem rotation, leaving the gate to upgrade, this Gate valve called the rotating rod valve or valve called the dark bar.
Rising stem gate valve is characterized stem drive lift gate together, drive screw on the stem exposed to the external body. Therefore, visually judged according to the direction of movement and position of the opening and closing position of the valve stem, and ease of transmission thread lubrication and corrosion from the fluid, but it requires a large installation space. In contrast, the dark bar gate drive screw located inside the body, in the opening and closing process, the valve stem rotates only without moving (gate in the valve body moves up and down). Therefore, the height dimension of the Gate valve when the valve opening is small, requires only a small installation space. Dark rod valve is usually installed in the valve cover side switch position indicator, which applies to ships, pipe trench, a large space is small and the dust content of the environment.
Gate Valve types, according to the sealing surface configuration can be divided into wedge gate-type valve and parallel gate-type valve, wedge gate-type valve can be divided into: single-gate type, gate-type double plate and elastic; parallel gate-type valve can be divided into single-gate type and double plate. Divided by the threaded stem position can be divided into two clear shot valve gate and dark bar. Valve closed, the sealing surface can only rely on media pressure to seal, which rely on media pressure to ram pressure to the sealing surface of the other side of the seat to ensure the sealing surface of the seal, which is self-sealing. Most of the valve is sealed by force, that is, when the valve is closed, the gate forced to rely on external pressure to the seat, to ensure the sealing surface of the sealing.
Gate Valve closed, the sealing surface can only rely on media pressure to seal, which rely on media pressure to ram pressure to the sealing surface of the other side of the seat to ensure the sealing surface of the seal, which is self-sealing. Most of the valve is sealed by force, that is, when the Gate valve is closed, the gate forced to rely on external pressure to the seat, to ensure the sealing surface of the sealing.
Source: http://www.gmkvalve.com
