- Introduction to the characteristics of bellows sealed stop valve:
Bellows stop valve is also called bellows sealed stop valve. Through automatic rolling welding, a metal barrier is formed between the fluid medium and the atmosphere to ensure the design of zero leakage of the valve stem. Compared with traditional stop valves, it has the following advantages:
1. Double sealing design (bellows + packing) If the bellows fails, the valve stem packing will also be avoided; the sturdy and durable bellows sealing design ensures zero leakage of the valve stem and provides maintenance-free conditions.
2. Reasonable structure, reliable sealing, excellent performance, and beautiful appearance.
3. No fluid loss, reduce energy loss, and improve factory equipment safety.
4. The sealing surface is surfacing Co-based hard alloy, wear-resistant, corrosion-resistant, anti-friction performance, long service life, reduce maintenance times, and reduce operating costs.
5. The sturdy and durable bellows sealing design ensures zero leakage of the valve stem and provides maintenance-free conditions.
6. The stem of the bellows stop valve is tempered and nitrided on the surface, which has good corrosion resistance and friction resistance;
- Introduction to the characteristics of ordinary sealed stop valves:
The stop valve, also known as the stop valve, is one of the most widely used valves. The reason why it is so popular is that the friction between the sealing surfaces during opening and closing is small, it is relatively durable, the opening height is not large, it is easy to manufacture and maintain, and it is suitable for both medium and low pressures and high pressures. The closing principle of the stop valve is to rely on the valve stem pressure to make the valve disc sealing surface and the valve seat sealing surface fit tightly to prevent the flow of the medium. The stop valve only allows the medium to flow in one direction and has directionality when installed. The structure of the stop valve is longer than that of the gate valve, and the fluid resistance is large. During long-term operation, the sealing reliability is not strong.
Characteristics of stop valves:
(1) The stop valve structure is simpler than the gate valve, and it is easier to manufacture and maintain.
(2) The sealing surface is not easy to wear and scratch, and has good sealing performance. There is no relative sliding between the valve disc and the valve body sealing surface during opening and closing, so the wear and scratch are not serious, the sealing performance is good, and the service life is long.
(3) When opening and closing, the valve disc has a small stroke, so the height of the stop valve is smaller than that of the gate valve, but the structural length is longer than that of 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 long.
(5) The fluid resistance is large, because the medium channel in the valve body is tortuous, the fluid resistance is large, and the power consumption is large.
(6) When the nominal pressure PN of the medium flow direction is ≤16MPa, the downstream is generally adopted, and the medium flows upward from the bottom of the valve disc; when the nominal pressure PN≥20MPa, the reverse flow is generally adopted, and the medium flows downward from the top of the valve disc. To increase the sealing performance. When in use, the medium of the stop valve can only flow in one direction and cannot change the flow direction.
(7) The valve disc is often eroded when fully opened.
- Disadvantages of the stop valve:
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 to coke.
3. The adjustment performance is poor.
3. Comparison between bellows sealed stop valve and ordinary sealed stop valve:
In industrial use, the leakage caused by the stop valve: high temperature, highly toxic, flammable and explosive, radioactive media, etc., not only pollutes the environment, but also often causes significant personal and property losses. The bellows sealed stop valve adopts the design of bellows seal, which completely eliminates the shortcomings of ordinary stop valve stem packing seal aging quickly and easy leakage. The bellows stop valve not only improves the energy efficiency, increases the safety of production equipment, reduces maintenance costs and frequent maintenance, but also provides a clean and safe working environment.