Stainless steel gate valve is the most widely used of all types of valves in modern industry. In this type of valve, a plate like a gate in the valve body moves vertically with the fluid between two matching valve seats, thereby opening or cutting off the flow path. Use it as a cut-off, and when the whole flow channel is fully open, the pressure loss of the medium is minimal at this time.
Understand the gate of the stainless steel gate valve:
Wedge type single gate:
The structure is simpler than the elastic gate valve:
At higher temperatures, the sealing performance is not as good as the elastic gate valve or the double gate valve;
Suitable for high-temperature media that is easy to coke.
Flexible gate:
Special form of wedge single gate. Compared with the wedge gate valve, at high temperature, the sealing performance is good, and the gate is not easy to be stuck after being heated; it is suitable for steam, high-temperature oil, oil and gas and other media, and is suitable for frequent switching positions. Not suitable for media that is easy to coke.
Double gate:
The sealing performance is better than that of the wedge gate valve. If the oblique angle of the sealing surface and the valve seat are not very accurate, it still has a better sealing performance;
After the sealing surface of the ram is worn out, replace the metal pad at the bottom of the top center of the spherical surface with a thicker one. Generally, it is not necessary to surfacing and grind the sealing surface, which is difficult to achieve with a single ram and an elastic ram;
There are more parts than other types of gate valves;
In addition to being suitable for steam, oil and other media, it is also suitable for parts that are frequently switched on and off and the medium that wears a lot to the sealing surface. It is not suitable for the medium that is easy to coke.
The flow passage of the valve body of the stainless steel gate valve can be divided into two types: full-diameter type and reduced-diameter type. The diameter of the flow channel is basically the same as the nominal passage of the valve, which is the full-diameter type; the diameter of the passage is smaller than the nominal passage of the valve, which is called the reduced-diameter type. There are two types of reduced diameter shapes: uniform diameter reduction and fee uniform diameter reduction. The taper-shaped flow channel is a kind of non-uniform diameter reduction. The aperture of the inlet end of this kind of valve is basically the same as the nominal diameter, and then gradually shrinks to the minimum at the valve seat.
The use of reduced-diameter flow channel has the advantage that the valve of the same specification can reduce the size, opening and closing force and torque of the gate; the disadvantage is that the flow resistance increases, the pressure drop and the energy consumption increase, so the shrinkage hole should not be too large. For tapered tube diameter reduction, the ratio of the inner diameter of the valve seat to the nominal diameter is usually 0.8-0.95. For reduced-diameter valves with a nominal diameter of less than 250mm, the inner diameter of the valve seat is generally one step lower than the nominal diameter; for reduced-diameter valves with a nominal diameter equal to or greater than 300mm, the inner diameter of the valve seat is generally lower than the nominal diameter by two steps.
