The pressure of the circulating water is fluctuating abnormally; I seek advice from experts!
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In our plant’s first circulation loop, the circulation flow rate, feed water pressure, and return water pressure have been fluctuating simultaneously over the past week. These fluctuations increase starting at 8 a.m., and gradually return to normal after 6 p.m. No change after switching the three circulation pumps ； It was verified that there were no changes in the operating conditions or procedures of all water-using units ； Inspections of pumps, motors, and other mechanical and electrical equipment by the M&E team revealed no abnormalities. I would like to ask the experts here for their guidance; I greatly appreciate any advice you can provide!
With your explanation of this issue, it’s pretty clear what the root cause is. Go and check the make-up water valve in the tank below the cooling tower to see if it’s damaged; this could be causing it to open and close frequently, resulting in significant fluctuations in the pipeline pressure. In severe cases, this might even lead to fluid shock and vibration in the pipelines. As for why it happened during those times you mentioned, it’s likely that hydration was frequent during those periods. I suggest you carry out these tasks: first, check the float valve and level control. You can manually cut off the water during those times you mentioned in the morning to see if there is still any fluctuation. The basic issue is exactly as I said
No problems have been found with the water supply valve at present; the water supply volume is steady, and the water level in the circulation tank is also stable. I’ll observe further; thanks to the expert for their guidance.
It’s not necessarily a fault with the valve itself; wait until there are again fluctuations, and then try turning off the water supply valve for two or three minutes. I’ve encountered several such situations. If that doesn’t work, I’ll find someone to help you figure out how to clean it
Does your factory use automatic control valves with circulating water to regulate temperature? If so, check the position of the control valve and the temperature when fluctuations occur; if they move in sync, then that’s the cause of the problem.
In a normal production cycle, there should be no significant fluctuations in the inlet and return water pressures. Your pressure monitoring points should be located on the main pipes; if fluctuations occur at certain times, it is likely that there is significant variation in water usage within the branch pipes during those periods, especially in those heat exchange devices that are located at higher levels. Please check all the branch pipes, and turn off the inlet and return valves of those devices that do not require cooling water. Adjust the flow rates of various valves to reduce uneven water distribution. The problem is likely to lie in the branch pipes, so please investigate this as soon as possible
The problem now is that only this one of the 5 circulating water systems has pressure fluctuations, while the others are operating normally.
Since the issue of increased pressure fluctuations arose, we have been checking the branch pipelines and have found no problems
It can be guessed that during commuting hours, high-power devices such as air conditioners in offices and on-site electric heaters are used extensively, resulting in a high electricity demand; this puts the stability of power supply to pump motors to the test. . . . .
Could you provide some parameters? What does synchronous fluctuation mean? What are the differential pressures and changes for the water inlet and outlet of the main pipe, as well as the changes in flow rate? Is the water consumption high during the day? In a continuous process, what is the relationship between main pipe pressure fluctuations and branch pipes? The bypass that allows the return water to flow directly into the tank is opened. Check if there are fluctuations. Anyway, if it’s a problem with the circulating water pipeline network. The pressure returning to the tower should be stable.