Working Principle of Sanitary Diaphragm Valve
Working principle of sanitary diaphragm valve
Sanitary 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 valve cover. The diaphragm valve is actually a "clamp" valve. An elastic and disturbing diaphragm is connected to the compression part with a screw spring. 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 (if it is a weir valve) or at the bottom of the contour (if it is a straight through type), Diaphragm valve is suitable for switching and throttling.
Structure of sanitary diaphragm valve
The sanitary diaphragm valve is equipped with a flexible diaphragm or combined diaphragm in the valve body and valve cover, and its closing part is a compression device connected with the diaphragm. The valve seat can be a weir or a pipe wall through the flow channel. The advantage of diaphragm valve is that its control mechanism is separated from the medium path, which not only ensures the purity of the working medium, but also prevents the possibility of medium in the pipeline impacting the working parts of the control mechanism. In addition, there is no need to use any form of separate seal at the valve stem, unless it is used as a safety facility in controlling harmful media. In the diaphragm valve, since the working medium contacts only the diaphragm and valve body, both of which can adopt a variety of different materials, the valve can ideally control a variety of working media, especially those with chemical corrosivity or suspended particles. The working temperature of diaphragm valve is usually limited by the materials used for diaphragm and valve body lining, and its working temperature range is about - 50 ~ 175 ℃. The diaphragm valve has a simple structure and is only composed of three main components: 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 operating mechanism is separated from the medium path, 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 a variety of artificial synthetic rubber and engineering plastics, as well as the wider selection of valve body lining materials, make the diaphragm valve widely used in various fields of modern industry.
Characteristics of sanitary diaphragm valve
The sanitary diaphragm valve separates the inner cavity of the lower valve body from the inner cavity of the upper valve cover by the diaphragm, so that the valve stem, valve disc and other parts above the diaphragm are not corroded by the medium, the packing sealing structure is omitted, and no medium leakage is generated.
1. The diaphragm made of soft seal such as rubber or plastic has good sealing performance. Since the diaphragm is a vulnerable part, it should be replaced regularly according to the characteristics of the medium.
2. Limited by diaphragm material, diaphragm valve is suitable for occasions with low pressure and relatively low temperature.
3. Diaphragm valves can be divided into six types according to their structural forms: house type, DC type, cut-off type, straight through type, gate type and right angle type; The connection form is usually flange connection; According to the driving mode, it can be divided into manual, electric and pneumatic. Among them, pneumatic drive is divided into normally open, normally closed and reciprocating.
4. Generally, it should not be used in pipelines with temperature higher than 60 ℃ and conveying organic solvents and strong oxidizing media, nor in pipelines with high pressure
Advantages of sanitary diaphragm valve
Due to the structural design of sanitary diaphragm valve itself, it is especially suitable for ultra pure medium or highly polluted and viscous liquid, gas, corrosive or inert medium. When combined with control equipment, diaphragm valve can replace other traditional control systems, especially for solid and easily polluted inert media. The products are mainly used in biopharmaceutical and food industries, as well as industrial water treatment in electric power, chemical industry, electroplating and other industries. They are also used in the production of semiconductor wafers. Diaphragm valve is especially suitable for transporting corrosive and viscous fluids, such as mud, food, medicine, textile adhesive, etc.
