Anti-freezing of centrifugal pumps
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How is the setting of the anti-freezing line for centrifugal pumps determined? I’ve seen some information stating that it is a line for cross-import and export; how does this line provide frost protection, and what is the difference in principle between it and a heat pump? I ask for the guidance of all teachers! This post was last edited by chengkang on 2009-4-10 07:20]
Anti-freezing measures for centrifugal pumps: Close the inlet and outlet valves, and drain all the fluid from within the pump by releasing it from the bottom. If there is a circulating cooling water system, it is best to disconnect this system as well and purge it to prevent water leakage that could cause damage to the pump. Strengthen the turning gear. Have never seen an antifreeze line
High-temperature oil pumps can be brought to a standby state through preheating using a preheating line, thereby achieving both anti-freezing and anti-condensation effects. Low-temperature oil pumps generally do not have pre-warming lines. The method we use is to slightly open the outlet valve to allow a small amount of fluid to flow back, thereby achieving anti-freezing and anti-condensation effects. However, it is necessary to prevent backflow of the fluid when the pump is turned off. If there is a check valve at the pump outlet, heating can also be used as a solution. The method provided above is generally used during periods when the plant is shut down for maintenance; if it is used during normal production, the pump cannot be put into standby mode. This post was last edited by lyybjgz on 2009-4-10 11:20]
Here, in winter, to prevent the pumps from being damaged by freezing, I installed what you could call anti-freezing valves. The approach is to keep the inlet valve open and the outlet valve closed. Since there are check valves at the outlet of the pumps, we added a valve before and after each check valve and connected them together! This thus serves as a pre-heating element for the high-temperature pump
In our centrifugal pumps, there is a line designed to prevent freezing, and the pipeline uses reclaimed water.
A heat pump primarily refers to a slow increase in temperature, with no more than 50 degrees per hour. The anti-freezing function of low-temperature centrifugal pumps that use water involves using the pump that is already in operation to force fluid to flow back into it, thereby keeping fluid moving inside the pump. If the temperature is low and the valve is set too narrow, the pump is prone to freezing; if it is set too wide, the pump may run in reverse, which is detrimental to the motor’s seals.
The anti-freezing line for centrifugal pumps is basically the same as that for heating pumps, and it usually runs across the outlet valve and check valve； When in use, open the inlet valve and use a freeze-proof line valve to control the flow rate, preventing the pump from reversing. There is also one that only crosses the check valve ； When in use, open the inlet and outlet valves, and use a freeze-proof valve to control the flow rate in order to prevent the pump from reversing.
Add a pre-heating line; if there is no such line, slightly open the outlet valve
The outlet valve should not be opened too wide, as this can cause the pump to run in reverse
The warm-up line functions as an anti-freezing and anti-condensation system; during maintenance shutdowns in winter, the inlet and outlet valves of the centrifugal pump can be closed to empty the pump of its contents, thereby ensuring unobstructed flow of cooling water and maintaining its temperature at around 10 degrees. During startup, for the standby pump, the outlet valve can be opened slightly (note: do not open it too much to prevent the pump from rotating in reverse); the inlet valve should be opened fully, and the material should be directed from the outlet of the operating pump to the outlet of the standby pump. For centrifugal pumps equipped with check valves, adding a bypass line to the check valve will solve the problem. :lol:victory::victory::victory:
During startup, the standby heat pump line can be slightly opened to allow the fluid to flow toward the inlet of the standby pump, thereby preheating it.
During operation, slightly open the outlet of the standby pump; an appropriate amount is sufficient. The criterion is that the standby pump does not start rotating in reverse, thereby allowing the medium to circulate and serving as a means of preheating the pump