Balancing valve correct selection and use methods

At present, most of the central air conditioning water system for two controls, winter and summer. In order to facilitate the resistance of the water system balance, the design engineer usually adopts water system with the program as soon as possible. But in actual engineering, sometimes as a result of the limitation of conditions, the designers will design some different water system. In addition, although the system loop water system with a program, but the system also exist serious resistance unbalance between loop. For air conditioning water system is the resistance of the unbalanced situation, through a variety of adjustment to the balance, is the prerequisite to ensure the normal operation of air conditioning water system is to guarantee comfortable air conditioning system with low energy consumption of the foundation of the indoor environment. In order to improve the regulating function of air conditioning water system, USES the good performance of the regulator doors to replace the current is still widely used gate valve gate, globe valve, butterfly valve door is imperative. At present, balance valves because of its comparatively complete function and good regulation performance, is more and more attention and welcome. Compared with other gate valve, balance valve mainly has the following features: ( 1) After the linear flow characteristic, namely in front of the valve under the condition of invariable pressure difference, flow and opening in general linear relationship. ( 2) Have the accurate opening instructions. ( 3) Opening the lock, the managers can't literally change the opening. ( 4) The valve body has two pressure holes, hose connection with intelligent instruments, can easily show the valve pressure difference and flow through the valve door after door. Although the balance valve has many advantages, but it is in air conditioning water system still exist many problems in the application. If these problems is not good, the characteristics of balance valve and is not fully revealed. The following balance valve used in air conditioning water system need to be aware of problems were discussed. 1 balanced valve problems that should be paid attention to. 1 selection problems that should be paid attention to in selecting some design engineer of balance valve, for convenience, often according to the nominal diameter pipe diameter to directly determine the valve door, in the practical heating air conditioning design manual 6 requirements so, actually this is not the best choice. Balance valve and gate valve gate, globe valve, butterfly valve door is different, in order to ensure accuracy, give full play to the regulation, should be chosen in satisfy the design discharge and differential pressure balance valve, the opening control between 60% ~ 90%, so that can meet the requirements of the design discharge, and there is a certain regulation margin, therefore, the balance of the selected nominal diameter of valve is not necessarily equal to the pipe diameter. 1. 2 write design specifications that should be paid attention to problems in the actual engineering design, there are few design engineer will need to consume of differential pressure balance valve and through the balance valve's flow in the design and construction instructions given, this brought difficulty to the regulation of system, also lost the advantages of balancing valves. If the design engineer in design and construction instructions associated with a balance valve parameters are given, it can provide convenience for the adjustment of the whole system conditions. Of course, due to the influence of various factors of the system is installed, under the design of the opening, measure the actual flow is not necessarily equal to the design flow. Can according to the actual measurement of flow, to open or close small balance valve fine-tuning, until satisfactory design flow value is reached. 1. 3 each partition main air conditioning water system and water pump export balance valve installation problems that should be noticed in an air conditioning water system is often based on the characteristics of air conditioning load is divided into several areas, each area is composed of a loop water system. While the division of water system loop may adopt the same program, but still exist between each loop resistance unbalance problem, it must be in full until the Siamese balance valve installed on each loop water mains, through the actual measurement of the return water temperature to adjust flow of each loop, make each link is running under the design flow rate. Balance valves, of course, can also be installed on the manifold of the water supply mains, the prerequisite is to make the balance valve pressure can satisfy the design requirements. Differ as a result of the load characteristic of winter and summer, back to the water temperature requirement is different, each partition water system water flow rate changed, the division of water system to balance, therefore, in choosing different water system of main balance valves, winter and summer conditions should be fully considered, determine an optimal nominal diameter of balance valve, to ensure the accuracy of the winter and summer balance valve adjustment. By the same token, the pump export director also want to consider in the selection of balance valves installed on the problem. If the pump adopts frequency conversion adjustment, do not need to consider the problem. 1. 4 balance valve installed on the problem for the balance of flow through valve before and after the water stability, guarantee the accuracy of measurement, balancing valve should be installed on the straight pipe, the balance valve before and after each should have 5 times and 2 times the diameter of straight pipe diameter. If a balancing valve is located in the pump on the outlet section of the valve is to be ten times the pipe diameter before long straight section. The design engineer in the process of system design, in addition to pay attention to the above requirements, should be on the drawings or instructions to the design and construction. In addition, the design engineer in the construction units for technical clarificaiton, should emphasize the balance valve installation requirements.