Control valve operation
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When adjusting the flow rate of a heat exchanger or throttling it using a control valve, should an upstream valve or a downstream valve be used? What are the specific impacts of this?
The heat exchanger is controlled by an outlet valve to prevent uneven flow and empty tubes.
I really hadn’t thought of that before; thank you. Are there any specific operation instructions or other reasons?
Can heat exchanger flow regulation be understood as temperature regulation of the cold and hot bypasses? Generally, the flow rate is adjusted at the outlet of the pump. Throttling through the control valve occurs either because the wrong type of control valve was selected, or due to production conditions that result in too low a load, making the control valve less sensitive. Another possible reason is blockage in the downstream valve; this is caused by excessive blockage in the upstream valve, which makes it difficult to control the adjustment range of the control valve
The flow regulation for the heat exchangers should be carried out in the same way as described for No. 2: to regulate oil-water heat exchangers, open or close the water outlet valve in order to control the temperature of the oil after it has been heated； When a control valve is unable to regulate the flow rate, one possible reason is wear and tear of the valve’s core; in the short term, the upstream and downstream valves can be used for adjustment, but if those valves also become ineffective over time, it is recommended to use a bypass line to isolate the control valve for repair.