In the industrial field, pumps and valves are important components in common fluid transfer and control systems. As a key component of the pump valve, the performance of the seal directly affects the overall performance and service life of the pump valve. This article will provide a detailed introduction to the common types of pump and valve seals, supplemented by data for reference.
First, the type of pump and valve seals.
1. Gasket seals.
Gasket seals are a common sealing element that is mainly used in flanged pump valves. Gasket seals are usually made of metal, asbestos, rubber and other materials, and the gasket is sealed tightly by pressing it to achieve the sealing effect. According to the different gasket materials and working conditions, gasket seals can be divided into metal gaskets, non-metallic gaskets and semi-metallic gaskets.
2. Packing seals.
Packing seals are mainly used in shaft seal structures to prevent the leakage of media by filling the gap between the shaft and the sealing cavity. Packing seals are usually made of fiber, rubber, PTFE and other materials, and can be divided into packing packing and braiding packing according to the use conditions.
3. Mechanical seals.
Mechanical seal is a kind of high-precision and high-reliability seal, which is mainly used in the sealing of rotating shafts. The mechanical seal is composed of a moving ring, a static ring, a spring seat, a gland, etc., and the sealing effect is achieved through precise fit and spring preload. Mechanical seals can be divided into two types: single and double-acting, and can be divided into dry gas seals, hydrostatic seals, etc. according to the working conditions.
4. Piston ring seals.
Piston ring seals are mainly used for piston motion seals in reciprocating pump valves. Piston ring seals are usually made of metal material and are sealed by a tight fit to the cylinder wall. Piston ring seals can be divided into two types: rigid rings and flexible rings, and can be divided into air rings and oil rings according to the working conditions.
2. Data and practical application analysis.
1. Practical application of gasket seals.
Gasket seals are widely used in pump valves, mainly in flanged piping systems. According to one study, the leakage rate can be reduced to less than 5% in flange connections using metal gaskets. At the same time, due to the good high temperature resistance and corrosion resistance of the metal gasket, it has good applicability under harsh working conditions such as high temperature, high pressure and corrosive medium.
2. Practical application of packing seals.
Packing seals are mainly used for sealing shaft seal structures, especially in some media containing suspended particles. According to the actual application data, the use of suitable braiding filler can effectively reduce the leakage rate of the medium to less than 1%. At the same time, due to the soft material of the packing seal, it can adapt to various shapes of shaft seal structure and is easy to install, so it is widely used in some small and medium-sized pump valves.
3. Practical application of mechanical seals.
As a high-precision and high-reliability seal, mechanical seals are widely used in key equipment in large-scale petrochemical, pharmaceutical and other fields. According to a study on the modification of a large centrifugal pump in a petrochemical company, the leakage rate was reduced to less than one-tenth of the original after the new mechanical seals were adopted, and the operating life of the equipment was extended by 50%. In addition, because the frictional resistance of the mechanical seal is small, it has good applicability to the shafting system that rotates at high speed.
4. Practical application of piston ring seals.
The piston ring seal is mainly used for piston movement sealing in reciprocating pump valves, and has good adaptability. According to the actual application data, the use of suitable piston rings can effectively reduce the leakage rate of the medium to less than 3%. At the same time, because the material of the piston ring seal is wear-resistant and corrosion-resistant, it has good applicability for some working conditions containing solid particles or corrosive media. However, piston ring seals require high manufacturing accuracy, so their application in some large reciprocating pumps is limited.