Characteristics
(1) The stop valve structure is simpler than the gate valve, and it is convenient to manufacture and maintain.
(2) The sealing surface is not easy to be worn and scratched, and the sealing property is good. There is no relative sliding between the valve flap and the sealing surface of the valve body when opening and closing, so the wear and the scratch are not serious, the sealing performance is good, and the service life is long.
(3) When opening and closing, the valve flap stroke is small, so the height of the shut-off valve is smaller than that of the gate valve, but the structural length is longer than the gate valve.
(4) The opening and closing torque is large, the opening and closing is more laborious, and the opening and closing time is the principal.
(5) The fluid resistance is large, because the medium passage in the valve body is tortuous, the fluid resistance is large, and the power consumption is large.
(6) When the nominal flow pressure of the medium is PN≤16MPa, the downstream flow is generally adopted, and the medium flows upward from the valve flap. When the nominal pressure PN≥20MPa, the counterflow is generally used, and the medium flows downward from above the valve flap to increase the seal energy. . When in use, the shut-off valve medium can only flow in one direction and cannot change the flow direction.
(7) The valve flap is often eroded when fully open.
The stem axis of the shutoff valve is perpendicular to the seat sealing surface. The valve stem has a relatively short opening or closing stroke and a very reliable shut-off action, making this valve suitable for use as a medium for cutting or regulating and throttling.
advantage
1. Simple structure, convenient manufacturing and maintenance.
2. The working stroke is small and the opening and closing time is short.
3, good sealing, small friction between sealing surfaces, long life.
4. The structure of the shut-off valve body is straight-through, direct-flow and right-angle. Straight-through is the most common structure, but its fluid resistance is greatest. DC fluid resistance is small, and it is mostly used for fluids containing solid particles or high viscosity. The right angle valve body is mostly forged, suitable for small through, high pressure shut-off valves.
5. The frictional force of the sealing surface is smaller and more wear-resistant than the gate valve during the opening and closing process.
6, usually only one sealing surface, good manufacturing process, easy to repair.
Stainless steel globe valve
Disadvantage
1. The fluid resistance is large, and the force required for opening and closing is large.
2. It is not suitable for media with particles, high viscosity and easy coking.
3. The adjustment performance is poor.
4. The bellows seal stop valve adopts the design of the bellows seal, completely eliminating the shortcomings of the normal valve stem packing seal aging and easy to leak, not only improving the energy efficiency, increasing the safety of the production equipment, reducing the maintenance cost and frequent Maintenance and maintenance also provides a clean and safe working environment.
Use advantage
1. Double seal design (corrugated pipe + packing) If the bellows fails, the stem packing will also be avoided;
2, external leakage, and in line with international sealing standards;
3. No fluid loss, reduce energy loss, and improve plant equipment safety;
4, long service life, reduce the number of maintenance, reduce operating costs;
5, rugged bellows seal design, to ensure zero leakage of the valve stem, providing maintenance-free conditions.
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