Regarding the control of the water supply temperature in the deaeration tank
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Water is fed into our deaeration tank, and it passes through a heat exchanger to raise the temperature of the deionized water. This process is controlled by a control valve located upstream of the heat exchanger; this same valve also regulates the liquid level in the deaeration tank. A control valve regulates the cold circuit, bypassing the heat exchanger. Normally, when the water temperature is high, we should turn on the cooling circuit and reduce the flow in the heating circuit as the liquid level rises. In practice, it’s impossible to operate the system at full capacity; at most ten valve positions can be opened, otherwise water hammer will occur in the pipelines. I would like to ask what the cause of this water hammer is and how to solve it Is it feasible to place the control valve of the hot circuit downstream of the heat exchanger?
Open the bypass line of the heat medium flow in the heat exchanger
The water injection volume should be constant. (1) The water supply volume should also be relatively stable. (2) The temperature of the deoxygenation tank should be set around 103 degrees to achieve deoxygenation; it cannot be too low. (3) Control valves should be installed on the bus to regulate the water volume, and the heat exchange temperature should be adjusted through the hot and cold circuits of the heat exchanger
Open the bypass line for the heat medium in the heat exchanger; however, it would be better to draw up a flow diagram to see if there are any better solutions
Water hammer occurs when superheated water that has been heated meets subcooled water that has not been heated, causing the superheated water to cool down suddenly. To prevent water hammer, it is necessary to control the amount of water that has not been heated, and the temperature of the water after heating should also not be too high; it’s worth considering whether there are any methods for adjustment
There is no phase change in the cold water pipeline, so how can water hammer occur? Is it because the pipe diameter is too large and the pressure is insufficient?
I think it’s the same; it’s not a matter of before or after. It’s caused by too high a temperature in the heat path, so the other end of that heat path needs to be adjusted
In the hot circuit, the flow rate through the heat exchanger is controlled by the liquid level control valve of the deaeration tank, while the temperature valve controls the cold circuit. If the temperature of the water entering the system is high, it is necessary to increase the flow rate in the cooling circuit; as a result, the liquid level in the deoxygenation tank rises, the control valve for the heating circuit closes, the flow rate decreases, and the water vaporizes
I drew a sketch myself; I think by water hammer you mean the vibration in the pipes and sink that is heard and felt when the cold water valve is opened, right? If that’s the case, I think it’s due to too much pressure from the cold water; when the cold water valve is opened, the shock caused by the cold water hitting the sink. As a solution, you can try reducing the pressure of the cold water, or change the water supply mode to one that uses drilling in a loop-shaped pipe to reduce pressure; this approach is likely to yield better results.
Both the cold circuit and the hot circuit come from the same pipeline. You’re right; when the cold circuit is operated at full capacity, the pipeline vibrates quite severely. As a result, it’s generally not advisable to open the control valve for the cold circuit to great extent in order to regulate the water temperature in the deaeration tank
This control method is not very appropriate, as water hammer will occur. Auxiliary lines and control valves should be added to the medium-pressure gas pipeline, with the feed water temperature signal for deoxygenated water connected to the control valve.