Issues with the setting of the drain valve 3
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What is the purpose of installing drain valves before and after the control valve?
The system fluid needs to be drained during maintenance.
In the case of steam pipes, it is necessary to warm the pipes before operation; this warming process generates condensate water. On one side, either in front of or behind the valve, the water cannot flow away directly, so a drain valve must be used to remove the water before steam can be pumped through the pipes. For reference only! !
Reply to 2# jhyy19802003: Does that mean a drain valve needs to be installed at both the front and back of all devices? All equipment and valves may require maintenance
Reply to 3# GLTANG2008: Why is it necessary to warm the pipes? Why can’t the liquid on one side be drained?
Warming the pipes is mainly to prevent excessive condensate from forming when steam is introduced, as this condensate can be pushed by the steam and impact pipe fittings, valves, and other components. The design flow rate for steam pipes is very high; therefore, steam carrying water poses a significant threat to the pipeline system. As for why the valve cannot drain water in a direct current manner, you just need to take a look at a valve sample and examine its structure to find out.
This post was last edited by GLTANG2008 on 2010-12-14 at 16:00. Even after heating the pipes, steam will still produce condensation water; however, if the amount is small, it doesn’t cause any problems. Don’t tell me you don’t know why the condensate water decreases after the pipes are warmed up. . . The impact of steam carrying water on pipes is commonly referred to as either \"water hammer\" or \"water shock\"; I can’t remember which exactly. . . . .
Pipelines carrying other media require steam purging upon completion or after being out of service for an extended period. Drain valves should also be installed on both sides of the valves in the following situations: 1. When the medium transported through the pipeline is sensitive to water content; 2. When the flow rate in the pipeline is high. Pipelines that require steam purging must definitely be equipped with low-level drain valves; the installation of drain valves on both sides of the valve depends on the specific circumstances.
Reply to 2# jhyy19802003: Does that mean a drain valve needs to be installed at both the front and back of all devices? All equipment and valves can potentially require maintenance. Generally, static equipment is equipped with inlet and outlet shut-off valves, as well as drain valves. This way, during maintenance, the liquid can be drained completely and then the area can be purged for use ； Moving equipment such as pumps also have discharge valves. All equipment and instruments must be depressurized and emptied before they can be handed over for maintenance.
Pouring liquid is a process of pouring; all control valves are equipped with front and rear manual valves for isolation purposes, for pouring liquid or for maintenance. Just as all storage tanks and pumps are equipped with valves for emptying, there are also proper valves; if they aren’t very large, a bypass heating pipe is used, and the discharge takes place through the drain valve. If the large valve with a diameter of several dozen inches also has a dedicated line for a 3/4-inch heating valve, it is located on the valve body.