Working principle and application of self-balanced valve
date:2026-01-07 11:03
The self-operated balancing valve is a new type of valve with automatic adjustment function, enabling dynamic balance in the pipe network. Commonly used types include self-operated flow balancing valves and self-operated pressure difference balancing valves. Their structures and working principles are as follows:
Working principle and application of self-balanced valve
(1) The function of a self-operated flow balancing valve is to maintain a constant flow through the valve under varying pressure differences between the inlet and outlet of the valve, thereby maintaining a constant flow in the controlled object (such as a loop, a user, a device, etc., the same below) connected in series with it.
Structurally speaking, the self-operated flow balancing valve is a dual-valve combination, consisting of a manual regulating valve group and an automatic balancing valve group (see Figure 1). The manual regulating valve group is used to set the flow rate, while the automatic balancing valve group is used to maintain a constant flow rate.
For manually adjusted valve groups, the flow rate G is given by G=Kv■, where Kv represents the flow coefficient of the manually adjusted valve port, and P2-P3 denotes the pressure difference across the manually adjusted valve port. The magnitude of Kv depends on the opening degree. If the opening degree is fixed, Kv becomes a constant. Therefore, as long as P2-P3 remains unchanged, the flow rate G remains unchanged. The constancy of P2-P3 is controlled by the automatic balancing valve group. For example, if the inlet and outlet pressure difference P1-P3 increases, the automatic balancing valve group will close slightly due to the action of the pressure-sensing membrane and spring, causing P1-P2 to increase, thereby maintaining the constancy of P2-P3. Conversely, if P1-P3 decreases, the automatic balancing valve group will open wider, causing P1-P2 to decrease and maintaining the constancy of P2-P3.
Each opening degree of the manually adjusted valve group corresponds to a specific flow rate. The relationship between the opening degree and flow rate is calibrated through tests on a test bench, and the valve group is equipped with a display and locking device for the opening degree.
