Water gate valve structure features and selection
Flat gate valve structure features:
1. The plate gate valve has two floating valve seats. Each valve seat is designed to seal in both directions when the medium flows. Therefore, the plate gate valve can not only realize two-way sealing but also can realize simultaneous sealing of the inlet and outlet. The valve seat adopts “Oâ€. The seal ring seal and the floating seat structure with preload applied by the spring, when the valve is heated to expand and cause the pressure of the middle chamber to be greater than the pressure of the pipeline, the pressure difference between the two sides of the medium acting on the valve seat will push the floating valve seat away from the gate. The pressure in the cavity is released into the pipeline through the gap between the gate and the valve seat, which effectively protects the safety of the valve, and the opening and closing moment of the structure is 1/2 of the ordinary valve, which can easily reach the open, Close the valve.
2. The valve seat adopts PTFE on the sealing surface, which has PTFE double seal for metal and metal to metal. The PTFE sealing surface also clearly removes the role of the gate plate. The metal-to-metal hard seal has a strong seal, erosion resistance, a variety of suspended particles in the pipeline medium, will not have any effect on the sealing pair, ensure no leakage, can completely compensate the wear of the sealing surface, at high temperature The lower gate will not get stuck because of the expansion, and it is suitable for frequent switching.
3. The valve body and the valve cover of the flat plate valve are designed with a grease injection valve. The sealing grease can enter the sealing surface of the valve seat through the grease injection valve on the valve body to play an auxiliary sealing role. The combined seal is More reliable and reaches zero leakage. Grease can be injected into the stem and packing through the filling spacer to play a role in auxiliary sealing through the grease injection valve on the valve cover, so that the seal can reach zero leakage reliably.
4. The flat gate valve with diversion hole, regardless of whether the fully open or fully closed gate plate always matches the sealing surface, the sealing surface is protected from the direct scouring of the medium, thus prolonging the service life. When the valve is fully open, the channel is smooth and straight, with a very low coefficient of yin and no pressure loss, and the pipeline can be cleaned through the hair bulb.
5. The flat-plate gate valve is a fully-sealed structure. The exposed stem is protected by a protective cover to prevent external impurities from entering the transmission. The visual indicator bar is installed on the valve to indicate the opening and closing state of the valve.
6. As the leading product of pipeline valves, plate gate valves are widely used due to their good sealing, high reliability and low manufacturing cost.
Slag discharge valve, knife gate valve performance characteristics:
1. The sluice sealing surface can be lifted, and the adhesive on the sealing surface can be scraped and the debris can be automatically removed;
2. Stainless steel gate plate can prevent seal leakage caused by corrosion;
3, the overall stainless steel material can prevent corrosion damage;
4, short structure length, can save raw materials, installation space, but also effectively support the strength of the pipeline;
5, scientific seal packing design, so that the seal is safe and effective, durable;
6, the triangular bracket saves raw materials, ensuring the required mechanical properties;
7. The guide block on the valve body makes the gate move correctly. The extrusion block guarantees effective sealing of the gate plate.
8, valve body reinforcement design to improve valve body strength;
9. The stainless steel valve stem is durable, and the double-headed screw makes the opening and closing of the benefit more rapid;
10, can choose any drive mechanism;
11, V-shaped gate can be used as a regulating valve
Installation and use:
1. Check the inside of the valve cavity and the sealing surface before installation, and do not allow any dirt or sand particles to adhere;
2. The bolts of each connecting part require uniform tightening;
3, check the packing site requirements compaction, both to ensure the sealing of the packing, but also to ensure that the opening board flexible;
4. Before installing the valve, the user must proofread the valve model, connection size, and pay attention to the medium flow direction to ensure consistency with the valve requirements;
5. When installing the valve, the user must leave the necessary installation space for valve actuation;
6, the wiring of the drive device must be carried out according to the circuit diagram;
7, the valve must be regularly maintained, not free to collide and squeeze, so as not to affect the sealing performance.
Globe valve construction and installation recommendations are introduced:
The structure of the cut-off valve is more complex, but the actual operation is simple and labor-saving. It has a good performance in adjusting the flow rate and cutting off the channel. The water-hammer phenomenon is very rare in the opening and closing speed. The shut-off valve is compact in structure and has more obvious features. The top of the valve is equipped with a hand wheel and a valve stem, and the middle part is provided with a thread and a stuffing box seal section.
The cut-off valve uses the valve stem to lift and move the valve head, thus changing the distance between the valve disk and the valve seat to achieve the opening and closing control. The cut-off valve is the most widely used cut-off valve in chemical production. Cut-off valve is mainly used for the control of water, steam, compressed air and other pipelines in actual production, but it should not be applied to materials with high viscosity and easy to crystallize.
The main way to determine the open and close state of the valve when using the stop valve is to observe the height of the valve stem to expose the valve cover to control the operation of the valve. There may be gaps in the part where the valve stem and the valve cover are connected, and media leakage is easy to occur, which can be solved by packing seal. The valve stem thread of the small cut-off valve is located in the valve body, so in use, the contact time with the medium is longer and it is easily corroded by the medium.
Therefore, in order to prevent the shut-off valve from having a short service life, the chief engineer of Butterfly Valves of Shen Die Valve believes that the installation of the shut-off valve should refer to the direction of the fluid and pay attention to keeping the fluid flow in and out of the pipeline, that is, flowing through the valve seat from the bottom up. The purpose of this installation is to reduce the fluid resistance in the valve body and thereby reduce the valve opening and closing force. At the same time, the valve stem and the stuffing box do not come into contact with the medium when the valve is closed, thereby reducing the occurrence of damage and leakage.
When the globe valve is installed and used, pay attention to the following three points:
1. The stop valve should be leak checked before opening to determine if the valve is leak free and the stuffing box is leak free.
2. If the valve stem operation of the globe valve cannot be completed manually, use a special F wrench instead. However, if the F wrench still cannot be opened, do not use the extension wrench to force open and close to avoid valve damage or even safety. The accident occurred.
3, when the cut-off valve is applied in the medium-pressure steam pipeline, condensate removal is required before opening, and then steam preheating is performed on the pipeline. The preheating pressure is maintained between 0.2 and 0.3 MPA. The purpose of doing so is to avoid the temperature. The seal is damaged due to a sudden change in pressure, and the pressure can be adjusted to the desired level after a stable state has been established.
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