Precautions and model of knife gate valve product in use: the opening and closing part of knife gate valve is the gate, and the movement direction of the gate is perpendicular to the fluid direction. Manual knife gate valve can only be fully opened and closed, and cannot be adjusted and throttled. The gate has two sealing surfaces. The two sealing surfaces of the most commonly used mode gate valve form a wedge shape, and the wedge angle varies with the valve parameters, usually 50. The gate of the wedge knife gate valve can be made into a whole, called a rigid gate; It can also be made into a ram that can produce slight deformation to improve its processability and make up for the deviation of the angle of the sealing surface during processing. This kind of ram is called elastic ram. When the knife gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the ram is pressed to the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface, which is self sealing. Most knife gate valves adopt forced sealing, that is, when the valve is closed, the gate plate should be forced to the valve seat by external force to ensure the sealing surface tightness. This type of valve should be installed horizontally in the pipeline.

The non-metallic expansion joint has some incomparable characteristics of the metal contraction joint. Its main characteristics are as follows:
(1) Good flexibility, no reverse thrust effect on equipment and system, great convenience for pipeline design, and improved safety of equipment and system
(The displacement absorbed per unit length of 2 J is large, and the displacement in three-dimensional direction can be absorbed.
(3) The device is simple and easy to change. There is no need for high request alignment, no need for lifting equipment, and the time required for change is short. At the same time, it can comply with the permanent misalignment of the pipeline caused by the settlement of the foundation after the medium or long-term work of the pipeline transformation:
(4) With strong adaptability, it can be shaped into arbitrary shape and arbitrary perimeter, such as rectangle, cone and plane.
(5) Good vibration isolation effect, close to zero vibration transmission.
(6) High temperature resistance can reach more than 1000 ℃.
(7) Corrosion resistance, the corrosion resistance of the data itself and the prevention of condensation and corrosion on the inside and outside
(8) Sound insulation, low noise and energy saving.