Application and Performance Analysis of Dynamic Balanced Electric Control Valve

With people's current living standards and energy conservation awareness continues to improve, variable flow system in the HVAC project occupy an increasingly important position, at the same time, a new type of hydraulic system - a fully balanced hydraulic system is also HVAC Engineering Get more and more widely used. A fully balanced hydraulic system generally regulates the temperature in the target area by dynamically adjusting the flow of the end-effec- tive electric regulating valve (such as an air conditioner box). It dynamically balances the pressure changes in the system so that the flow between two or more end devices The adjustment does not interfere with each other, so this system is highly energy-efficient. At present, in some air-conditioning projects, some designers use the combination of dynamic flow balance valve and electric control valve instead of the dynamic balance electric control valve in order to achieve the same function, claiming that the two configurations have the same function. Then the dynamic flow balance valve and electric control valve combination can replace the dynamic balance of electric control valve what, the following two features of these configurations for some analysis and comparison. Scope of application Urban construction, chemical industry, metallurgy, petroleum, pharmaceutical, food, beverage, environmental protection Dynamic balance Electric control valve performance analysis Dynamic balance electric control valve is different from the traditional electric control valve of a new generation of products, is the dynamic balance and electric regulation integration Of the products, it has the following characteristics: 1 has excellent electric adjustment function: electric adjustment function is the valve according to the target area temperature control signal changes automatically adjust the valve opening, thereby changing the water flow, and ultimately make the target area of ​​the actual The temperature is consistent with the set temperature. Evaluation of electric regulation function is good or bad is the flow characteristics of electric control valve. In the air conditioning system, the ideal flow characteristics of the common electric control valve is straight or equal percentage. However, for the general electric control valve, the actual flow characteristic curve deviates from the ideal flow characteristic curve due to the lesser valve authority in actual use. As shown in Fig. 3, the ideal flow characteristic curve of a motorized control valve is a straight line (curve 1), but the actual flow rate curve close to the quick-open type (curve 2) after installation on the system line deteriorates the adjustment characteristics. Dynamic balance of electric control valve due to the unique structure of the valve in the actual use of the project the valve is basically 1, so the actual flow characteristics of the curve and the ideal flow characteristics of the same, there is no deviation, it has excellent motor control function . 2 has a dynamic balance function: dynamic balance function is based on changes in the load requirements of the end equipment electric regulator valve to a certain opening, no matter how the system pressure changes, the valve can dynamically balance the system's resistance, so that traffic is not System pressure fluctuations remain the same. Assuming the summer conditions, the first one has been adjusted to the balance, that is, the target zone temperature T1 has stabilized at 25 ℃, then the dynamic balance of the electric valve opening maintained at a certain position to maintain a constant output flow. Zone 2 is still in an unstable state, the measured return air temperature T2 is 24 ℃, lower than the set temperature 27 ℃, then the measured temperature and the set temperature in the temperature controller to compare the output signal will be dynamic balance valve closed So as to reduce the amount of cold water flowing through the air handler 2. At this moment, the cooling capacity will be reduced, so that the measured temperature T2 will rise up to the set temperature. At the same time, the pressure difference between the two points of the system risers C and D will increase, A loop air balance valve pneumatic valve DV1 at both ends of the two C, B1 two point pressure increases accordingly. However, due to the dynamic balance of the dynamic balancing valve (the function of the constant pressure difference of the dynamic balance valve PV1), the pressure difference at the two ends A1 and B1 of the valve does not change, Of the flow remained unchanged, the cooling capacity unchanged, the corresponding area is still in a state of balance (Figure 2 for the dynamic balance of electric control valve dynamic balance curve). It can be seen from the above that the adjustment of the second loop of the air handler does not disturb the first loop of the air handler that has been balanced, so there is no dynamic hydraulic imbalance between the two loops. For a multi-loop system, the adjustment of any one loop will not interfere with the other loops, and any one loop will not be affected by other loop adjustments. The larger the system, the more dynamic balance Obviously, each loop is only affected by the change of regional load, and not affected by system pressure fluctuations, so it is easy to reach and maintain equilibrium. More keyword search: Regulating valve