Definition and principle of the hottest diaphragm

2022-10-22
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Definition and principle of diaphragm valve

diaphragm valve is a special form of block valve. Its opening and closing part is a diaphragm made of soft material, which separates the inner cavity of the valve body from the inner cavity of the bonnet. In fact, the diaphragm valve is just a clamp valve, an elastic and disturbing diaphragm, which is bolted to the compression part. The compression part is operated by the valve rod and moves up and down. When the compression part rises, the diaphragm will be raised to create a passage. When the compression part falls, the diaphragm will be pressed on the weir of the valve body (assuming weir type valve) or on the bottom of the contour (assuming straight through type). The diaphragm valve is suitable for switching and throttling

the working temperature of British standard diaphragm valve is usually limited by the materials used for diaphragm and valve body lining, and its working temperature range is about - 50 ~ 175 degrees. The structure of diaphragm valve is simple, which is only composed of three main parts: valve body, diaphragm and bonnet assembly. The valve is easy to disassemble and repair quickly, and the replacement of diaphragm can be completed on site and in a short time. The sample 1 with large experimental force of the operating mechanism and medium passage generally adopts the inclined clamping structure. With the increase of the experimental force, the clamping force increases and separates, so that the diaphragm valve is not only suitable for the production of food and medical and health industry, but also suitable for some difficult and dangerous media. The application of more kinds of artificial synthetic rubber and engineering plastics, as well as the wider selection of valve body lining materials, make diaphragm valves widely used in various fields of modern industry

the national standard rubber lined and fluorine lined diaphragms still have a particularly large demand for the foam granulator industry. The structural design of the space valve itself is particularly suitable for ultra pure media or highly polluted, very viscous liquids, gases, corrosive or inert media. When combined with control equipment, the national standard rubber lined and fluorine lined diaphragm valve can better replace other traditional control systems, especially for solid and easily polluted inert media. The products are mainly used in biopharmaceutical, food and industry; As well as industrial water treatment in electric power, chemical industry, electroplating, and other industries, some of them have been used in the production of semiconductor wafers. Diaphragm valves are especially suitable for transporting corrosive and viscous fluids, such as mud, food, drugs, textile adhesive fluid, etc. because the operating mechanism of diaphragm valves in pipelines is not exposed to the transport fluid, they are not polluting and do not need fillers, The valve stem packing is also unlikely to leak

the principle of British standard rubber lined and fluorine lined diaphragm valve is the reverse regulation in the valve body. When the pressure at the inlet increases, the diameter will be automatically reduced to reduce the change of flow, and vice versa. If the connection is reversed, the regulating system will not work. Moreover, the regulating valve plate is directional, and the reverse pressure can even reduce or even close the flow. Since the diaphragm valve is installed for better heating, there is no reverse installation problem. If it is a reverse installation, it is a human error, and of course it will be corrected. The working principle is to adjust the flow by changing the clearance (i.e. opening) between the valve core and the valve seat and changing the flow resistance of the fluid flowing through the valve. Diaphragm valve is equivalent to a throttling element whose local resistance can be changed. For incompressible fluid, it can be obtained from the flow equation

kv is the valve coefficient of direct flow rubber lined diaphragm valve. Its definition is: when the differential pressure between the front and rear of the once through rubber lined diaphragm valve is 1bar (about 1kgf/cm2), the flow through the diaphragm valve (m3/h). The valve coefficient of once through rubber lined diaphragm valve when fully opened is equivalent to the flow capacity of ordinary valves. If the opening of the balance valve remains unchanged, the valve coefficient kV remains unchanged, that is, the valve coefficient kV is determined by the opening. By measuring the valve coefficients under different opening degrees, the diaphragm valve can be used as a throttling element for quantitative flow regulation

when debugging the pipe diaphragm, connect the pressure measuring small valve of the diaphragm valve to be debugged with a special intelligent instrument with a hose, and the instrument can display the flow value (and pressure drop value) flowing through the valve. Open the switch;, After man-machine dialogue with the instrument and inputting the required flow value at the diaphragm valve to the instrument, the instrument obtains the opening value of the valve when the pipeline system reaches hydraulic balance through calculation and analysis

diaphragm valve belongs to the category of regulating valve. The working principle of internal thread diaphragm valve is to adjust the flow by changing the gap between the valve core and the valve seat and changing the flow resistance of fluid flowing through the valve

1. Do not change the opening of diaphragm valve at will. After the installation of the pipe system is completed and the test conditions are met, use the special intelligent instrument to debug and set all diaphragm valves, and lock the opening of each valve, so that the pipe can realize the balance of hydraulic working conditions. During the normal operation of the pipe system, the opening of the diaphragm valve should not be changed at will, especially the opening locking device

2. There is no need to install a stop valve. When overhauling a loop, the diaphragm valve on the loop can be closed. At this time, the diaphragm valve acts as a stop valve to cut off the water flow, and then return to the original locked position after overhauling. Therefore, if the diaphragm valve is installed, it is no longer necessary to install the stop valve

3. When the system adds (or cancels) a loop, it should be debugged and set again. When adding (or canceling) a loop in the pipe system, in principle, all new diaphragm valves and diaphragm valves in the original system loop should be debugged and set again (the branch diaphragm valve in the original loop does not need to be readjusted), except that the corresponding diaphragm valve should be added (or closed). In the air conditioning and heating system, the hydraulic balance of the water circulation system as the transmission and distribution of energy is very important

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