A..TSThere are many types of diaphragm valves, and there are a variety of classification methods. Here mainly according to the structure of the diaphragm valve classification.
Weir (ridge) diaphragm valve.
The weir of a weir diaphragm valve is a part of the body equivalent to the valve seat on which the diaphragm presses to truncate the medium flow. Diaphragm valves of this type are generally larger in size. The raised weir reduces the travel of the diaphragm valve from fully open to fully closed, thus reducing the stress and strain on the diaphragm. When closed, the diaphragm disc moves down to seal with the weir (spine) of the body to cut off the fluid.
Straight flow diaphragm valve has the characteristics of globe valve and roof diaphragm valve.
The valve seat is sealed by metal disc coated with non-metallic materials, which has higher bearing capacity and sealing performance. Another diaphragm as a flange seal and stem packing seal, and as an isolation valve body and valve cover barrier, reliable seal, valve body flow channel is linear, flow capacity is good. Flow resistance coefficient is small, valve body cavity can be lined with plastic, lining rubber.
Straight-through diaphragm valve.
The flow channel of the straight-through diaphragm valve is approximately straight. The flow resistance is small, and the stroke is longer (relative to the weir). The diaphragm flexibility requirements are higher, cutting performance and flow performance are good, corrosion resistance, can contain granular medium, the inner cavity is not lined and lined with plastic, rubber, lining enamel, etc.
When the straight-through valve is opened, its diaphragm rises, making free flow in any direction. When the valve is closed, the diaphragm seal is tight and can be guaranteed.
Pneumatic diaphragm valve.
Pneumatic diaphragm valve is a special form of cut-off valve that appeared in the 1920s. Its opening and closing part is a diaphragm made of soft material. The valve body cavity and the cover cavity and drive parts separated. So called pneumatic diaphragm valve.
Pneumatic diaphragm valve is the most prominent characteristic of the lower valve body cavity and the upper valve cover cavity separated. So that located above the diaphragm stem, valve disc and other parts are not corroded by the medium, omit the packing seal structure, and will not produce media leakage.
Pneumatic diaphragm valves are characterized by a set of thin hemispherical metal films clamped into the body as a barrier between the stem and the fluid. Valve closing is achieved by pressing the disc against the seat with the stem head and metal film. The valve is opened by an internal spring. and when the stem is lifted and out of contact with the film, the disc is lifted. Because the stroke of the valve is equal to the stroke of the film. The characteristic lift of this valve is much smaller than that of ordinary valves.
