Structural features of the gate valve for Sanjing water
Structural features of the slab gate valve:
1. The slab gate valve has two floating valve seats. Each valve seat is designed to be sealed when the medium flows in both directions. Therefore, the slab gate valve can not only realize two-way sealing but also realize simultaneous sealing at the inlet and outlet. The valve seat adopts “Oâ€. The sealing ring structure of the seal ring and the spring applying the preload force. When the valve is heated and the pressure of the middle cavity is greater than the pressure of the pipe, the pressure difference between the two sides of the valve seat will push the floating valve seat away from the gate. The pressure in the middle chamber is discharged into the pipeline through the gap between the gate and the valve seat, thereby effectively protecting the safety of the valve, and the opening and closing torque of the structure is 1/2 of that of the ordinary valve, which can be easily opened, Close the valve.
2. The valve seat is inlaid with PTFE on the sealing surface, and has double sealing of PTFE to metal and metal to metal. The PTFE sealing surface also clears the function of the ram. The metal-to-metal hard seal has strong sealing and erosion resistance. The pipeline medium has various suspended particles, which will not have any influence on the sealing pair, and can ensure no leakage. It can fully compensate the wear of the sealing surface at high temperature. The lower shutter does not get stuck due to expansion and is suitable for places where it is frequently switched.
3. The valve body and the valve cover of the slab gate valve are designed with a grease injection valve. The grease can enter the sealing surface of the valve seat through the grease injection valve on the valve body to play the auxiliary sealing function, and the sealing is more reliable, achieving zero leakage and sealing. The grease can be injected into the valve stem and the packing through the packing ring on the bonnet to assist the sealing, so that the seal can reliably achieve zero leakage.
4. The slab gate valve with diversion hole, whether the fully open or fully closed ram is always matched with 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, the flow coefficient is very small, no pressure loss, and the pipeline can be cleaned by the ball.
5. The slab gate valve is fully sealed. The exposed valve stem is protected by a protective cover to prevent external impurities from entering the transmission. The valve is equipped with a visible indicator rod to indicate the opening and closing of the valve.
6. As a leading product of pipeline valves, slab gate valves are widely used due to their good sealing performance, high reliability and low manufacturing cost.
Slag gate valve, knife gate valve performance characteristics:
1. The ram seal surface can be lifted to scrape the adhesive on the sealing surface and automatically remove debris;
2, stainless steel ram 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, and also effectively support the pipeline strength;
5. The scientific upper sealing packing design makes the upper sealing safe and effective and durable;
6. The triangular bracket saves raw materials and ensures the required mechanical strength;
7. The guide block on the valve body causes the shutter to move correctly. The pressing block ensures that the shutter is effectively sealed;
8. The valve body rib design improves the strength of the valve body;
9. The stainless steel valve stem is durable, and the double-headed screw makes the opening and closing of the benefit more rapid;
10. The drive mechanism can be arbitrarily selected;
11, V-type shutter can be used as a regulating valve
Installation and use:
1. Check the valve cavity and sealing surface before installation, and do not allow dirt or sand to adhere;
2. The bolts at each joint are required to be evenly tightened;
3, check the filling site requires compaction, not only to ensure the sealing of the packing, but also to ensure that the plug-in board is flexible;
4. The user must check the valve type before connecting the valve, connect the size and pay attention to the flow direction of the medium to ensure consistency with the valve requirements;
5. When installing the valve, the user must retain the necessary installation space for the valve drive;
6. The wiring of the drive unit shall be in accordance with the wiring diagram;
7, the valve must be maintained regularly, not free to collide and squeeze, so as not to affect the sealing performance.
Introduction to the construction and installation of the shut-off valve:
The structure of the stop valve is more complicated, but the actual operation is simple and labor-saving. It has a good performance in regulating the flow rate and the cut-off passage, and the water-hammer phenomenon is rarely caused by the slow opening and closing speed. The shut-off valve has a compact structure and a distinctive shape. The top of the valve is provided with a hand wheel and a valve stem, and a threaded and stuffing box sealing section is arranged in the middle.
The shut-off valve is a valve that uses the valve stem to lift and move the valve head, thereby changing the distance between the valve disc and the valve seat to achieve the opening and closing control. The shut-off valve is a truncated valve in the chemical production range. The shut-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 crystallization.
The main way to judge the opening and closing state of the valve when the valve is in use is to observe the height of the valve stem exposed to the valve cover to control the operation of the valve. There may be gaps in the part of the stem that is connected to the bonnet, which is prone to media leakage, which can be solved by a packing seal. The stem thread of the small shut-off valve is located in the valve body, so it is often in contact with the medium for a long time in use, and is easily corroded by the medium.
Therefore, in order to prevent the service life of the shut-off valve from being short, the chief engineer of Xiandie Valves believes that the installation of the shut-off valve should refer to the direction of the fluid. Pay attention to keeping the flow of the pipeline low and high, that is, flowing from the bottom to the valve seat. The purpose of this installation is to reduce the fluid resistance in the valve body and reduce the valve opening and closing force, while maintaining the valve stem and stuffing box not in contact with the medium when the valve is closed, reducing damage and leakage.
When installing the valve, the following three points should be noted:
1. The shut-off valve should be leak checked before opening to determine whether the valve has no leakage defects and whether the stuffing box has no leakage defects.
2. If the valve stem operation of the shut-off valve cannot be completed by hand, a special F-wrench can be used instead, but if the F-wrench still cannot be opened, do not use an extension wrench to open and close forcibly to avoid damage or even safety of the valve. The accident happened.
3. When the shut-off valve is applied to the medium-pressure steam pipeline, the condensate should be removed before opening, and then the steam is preheated to the pipeline. The preheating pressure is maintained between 0.2 and 0.3 MPA. The purpose of this 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 the state is stabilized.
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