1 Application Significance (1) Self-operated pressure control valve consumes the system's rich head. (2) Self-operated differential pressure control valve play a role in isolating the user flow changes interfere with each other. Some people in the two functions think that the thermostatic valve on the radiator can work, in fact, if the temperature control valve to produce such a role will inevitably lead to the temperature control valve in a small opening, even under vibration conditions jobs. This is very unfavorable to the thermostatic valve, the initial hope of the thermostatic valve is limited to the use of free heat, and many of our industry's hopes of placing it too large. (3) Self-operated differential pressure control valve to isolate the user traffic changes interfere with each other. 1, the original work point 2, the user automatically adjust the flow of the formation of the work point 3, the circulating pump speed - the formation of operating pressure differential valve 4, the circulating pump speed differential pressure valve operating point (4) for the electric control Automatic control system, isolated from the regulation of the parallel branch interference, to avoid unnecessary movement of the automatic control system to improve the stability and reliability of the control system. (5) play a special operating conditions of the current limit. In start-up and special cold conditions, the heat demand of the user will exceed the heating capacity of the heat source. The self-operated differential pressure control valve will effectively limit the near-end flow so that the remote user can achieve the predetermined heating effect. 2 self-operated pressure control valve selection parameters. (1) adjustable pressure difference Under normal circumstances, the design is difficult to accurately calculate the indoor resistance, and indoor resistance (at the design flow) may vary between 0.01-0.03MPa, so the adjustable self-pressure than the minimum should be 1: 3 above. (2) The maximum and minimum flow coefficient Kv The maximum flow coefficient is the valve full open flow coefficient; the minimum flow coefficient is the valve full close bit leakage factor. These two valve parameters of the valve application selection is crucial, the valve supplier must be measured and disclosed these two parameters. The maximum flow coefficient should be able to ensure that the design flow under the minimum pressure head; minimum flow coefficient should be able to ensure that the maximum maximum flow under the pressure head to adjust the conditions may be the minimum flow value. (3) Differential pressure control accuracy should reach 10% to ensure flow accuracy of 5%. .3 Self-operated differential pressure control valves also function as a constant flow distributor in the case where the heat control indicator is not installed in the household control. The adjustment method only needs to adjust and control the differential pressure flow to reach the designed flow rate. And self-flow control valve the same branch flow adjustment do not interfere with each other to adjust the flow can be completed once. Therefore, in most of the projects that implement household-controlled metering and charging, self-operated differential pressure control valves should also be adopted. In the unmetered charges before the differential valve can also balance the distribution of flow, to avoid the installation of gauges, to replace the valve. More Keyword Search: Control Valve