22

2019

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10

Valve pressure bearing direction instructions and installation direction requirements

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As the name suggests, the pressure bearing of a valve refers to the pressure that the valve can withstand, that is, the pressure level of the valve is not lower than the design pressure level of the pipeline. The pressure-bearing direction refers to the closed state of the valve after it is used in pipeline conditions. The arrow direction of the valve body is the direction recommended to withstand pressure. If installed incorrectly, leakage failure may occur due to lax closing of the valve. Generally, it is determined based on the process flow or usage conditions. The same direction refers to the pressure-bearing direction (the side with high medium pressure on both sides of the valve gate) and the flow direction. The opposite direction refers to the pressure-bearing direction (both sides of the valve gate). The side with high medium pressure) is opposite to the flow direction of the medium.

As the name suggests, the pressure bearing of a valve refers to the pressure that the valve can withstand, that is, the pressure level of the valve is not lower than the design pressure level of the pipeline. The pressure-bearing direction refers to the closed state of the valve after it is used in pipeline conditions. The arrow direction of the valve body is the direction recommended to withstand pressure. If installed incorrectly, leakage failure may occur due to lax closing of the valve. Generally, it is determined based on the process flow or usage conditions. The same direction refers to the pressure-bearing direction (the side with high medium pressure on both sides of the valve gate) and the flow direction. The opposite direction refers to the pressure-bearing direction (both sides of the valve gate). The side with high medium pressure) is opposite to the flow direction of the medium.

 

  

Many valves are directional, such as stop valves , throttle valves , pressure reducing valves , check valves , etc. If installed upside down, If installed backwards, the use effect and life will be affected (such as a throttle valve), or it will not work at all (such as a pressure reducing valve), or even cause danger (such as a check valve). Generally, valves have direction marks on the valve body; if not, they should be correctly identified based on the working principle of the valve.

 

The arrow marked on the valve body is the recommended pressure-bearing direction of the valve, not the flow direction of the pipeline medium. A valve with a two-way sealing function may not be marked with an indicator arrow, or may be marked with an arrow, because the valve arrow refers to the recommended pressure-bearing direction. One of the two directions, left or right or up and down, is always better. They are often installed incorrectly by engineering and installation companies as media flow direction markers, causing leaks and even pipeline accidents .

 

  The valve cavity of the stop valve is asymmetrical from left to right, and the fluid must pass through the valve port from bottom to top. In this way, the fluid resistance is small (determined by the shape), and it is labor-saving to open (because the medium pressure is upward). After closing, the medium does not press the packing, which is convenient for maintenance. . This is why the stop valve cannot be installed reversely. Other valves also have their own characteristics . The location of the valve installation must be convenient for operation; even if the installation is temporarily difficult, the long-term work of the operator must be considered. It is best to position the valve handwheel flush with the chest (usually 1.2 meters away from the operating floor ), so that it is easier to open and close the valve. The handwheel of the floor-standing valve should be facing upwards and not tilted to avoid awkward operation.

 

The valves of the wall-mounted equipment should also leave room for the operator to stand. Avoid operating with your head up, especially with acids, alkalis, toxic media, etc., otherwise it will be very unsafe.

 

Do not install the gate valve upside down (that is, with the hand wheel facing downwards), otherwise the medium will remain in the valve cover space for a long time, easily corroding the valve stem, and is contraindicated by certain process requirements. It is extremely inconvenient to replace the packing at the same time. Do not install rising stem gate valves underground, otherwise the exposed stem will be corroded by moisture. When installing the lift check valve, ensure that its valve disc is vertical so that it can lift flexibly. When installing the swing check valve, ensure that its pin is level so that it can swing flexibly. The pressure reducing valve should be installed upright on a horizontal pipe and should not be tilted in any direction.