Top Scraper Seals

Mechanical seal for pump refers to a device installed and operated in pump equipment to perform a dynamic sealing function to prevent the fluid medium in the volute of the water pump from flowing out through the pump shaft and to mechanically seal the outside of the water pump. Centrifugal pump shutdown is mainly caused by the failure of mechanical seals. Most of the symptoms of failure are leaks, and the causes of leaks are as follows: 1. Leakage of dynamic and static ring sealing surfaces The main reasons are: the flatness and roughness of the end face do not meet the requirements, or the surface is scratched; there are particulate matter between the end faces, causing the two end faces to not operate equally; the installation is not in place and the method is incorrect. 2. Compensation ring seal leakage The main reasons are: gland deformation, uneven preload force; incorrect installation; sealing ring quality does not meet standards; sealing ring selection is incorrect. The most common parts of the sealing element failure are the end faces of the dynamic and static rings. Cracks on the end faces of the dynamic and static rings of centrifugal pumps are common failure phenomena. The main reasons are: 1. The gap between the sealing surfaces is too large during installation The flushing fluid is too late to take away the heat generated by the friction pair; the flushing fluid leaks from the gap between the sealing surfaces, causing the end face to overheat and be damaged. 2. Vaporization and expansion of liquid medium The two end faces are separated by the vaporization expansion force. When the two sealing faces are forced to fit together, the lubricating film is destroyed and the end face surface is overheated. 3. Liquid medium has poor lubricity When the operating pressure is overloaded, the two sealing surfaces will track and rotate out of synchronization. When one sealing surface lags behind and cannot track the rotation, the instantaneous high temperature will cause damage to the sealing surface. The orifice plate or filter of the seal flushing liquid is clogged, resulting in insufficient water and causing the mechanical seal to fail. There are sliding grooves on the surface of the sealing surface, and gaps appear when the end faces are attached, resulting in the failure of the sealing element. The main reasons are: 1. The liquid medium is not clean There are tiny hard particles that slide onto the sealing surface at a very high speed, scratching the end surface and causing it to fail. 2. Poor coaxiality of pump transmission parts After the pump is turned on, the end face is shaken and rubbed once every revolution, and the moving track of the moving ring is not concentric, causing the end face to vaporize and overheat and wear. 3.Sealing surface misalignment failure Corrosion of sealing elements by liquid medium, stress concentration, combination of soft and hard materials, erosion, auxiliary sealing O-rings, V-rings, concave rings and liquid medium incompatibility, deformation, etc. will all cause damage to the mechanical seal surface, so The damage pattern must be comprehensively analyzed to find out the root cause and ensure the long-term operation of the mechanical seal.

New breaker structureTechnical applications:This technology is a new breaker structure developed by studying the damage mechanism of breaker seals. It can solve the common problems of current hydraulic breaker that the seals are easily damaged and the piston is easily strained.Technical points:1. Add guide rings to the seals at both ends of the cylinder cavity to guide the piston movement and reduce the impact of the piston radial force on the seals.2. Change the gap seal of the piston to a floating seal. The outer ring surface of the floating seal fits with the inner wall of the cylinder and serves as a seal. The inner ring surface is suspended. The upper and lower surfaces take turns to fit with the two walls of the installation groove during operation and serve as a seal. Function, improve the cylinder sealing effect and increase the cylinder output efficiency.                                 Technical advantages:1. The piston sealing gap is small and there is less leakage. The breaker efficiency is improved, the oil heat is reduced, and the life of the oil and breaker is extended.2. The machining concentricity requirements of the piston and cylinder can be reduced by 1-2 levels, and the machining cost is reduced.3. There is no contact between the piston and the cylinder cavity, so there is no risk of cylinder pulling, and the service life of the hammer is greatly extended.4. The distance between the two guide points increases, the guiding ability is significantly enhanced, and the radial impact of the piston is small.

1. LightweightThe transportation department has strict requirements for walking and moving requirements, and the road weight of walking machinery.In order to reduce the weight of concrete pump trucks, some companies use aluminum alloy to make the cylinder components, and some even use carbon fiber to make the entire arm.2. Energy savingThe green world trend actually requires efficiency of oil cylinders. Improving the efficiency of oil cylinders directly saves energy.The efficiency of the oil cylinder is the ratio of the output work of the oil cylinder to the input work. This value is between 0.7-0.98. Different oil cylinders vary greatly, usually between 0.9-0.95. The loss of power mainly comes from three aspects: seal friction loss, internal leakage loss, and oil throttling loss. For cylinders of different designs and working conditions, these three losses are very different. For example, in a domestic The friction loss of a main cylinder of a pump truck from a large company during normal operation can reach nearly 20KW. The intuitive feeling of the efficiency of the oil cylinder is that the actual output force of the oil cylinder is smaller than the theoretical value, and the efficiency measurement is also based on this point.3. IntelligentMechanical automation requirementsMechanical automation requires sensing the real-time working status of the cylinder and controlling it. Therefore, sensors and action controllers (various valves) need to be installed on the cylinder, which puts forward new requirements for the structure and sealing of the cylinder.4. Low failure rate and long lifeLow cost of useThe failure rate directly determines the use cost of machinery to a large extent. For oil cylinders, the failure rate of the sealing system accounts for about 70%. Therefore, for oil cylinders, the reliability of the sealing system is the decisive factor in the use cost.5. Environmentally friendlyLittle or no pollutionThe working medium does not leak or even if it leaks, it has no impact on the environmentDesign better sealing systems and seals to reduce leakage; use working media that do not pollute the environment.It is theoretically impossible that the working medium will never leak, and it is even more impossible in practice. Therefore, using water as the working medium has once again become the direction of people's efforts, because even if water leaks, it will not cause adverse effects on the environment.6. Low costLow cost and relatively cheap price can be purchased and used, which requires cylinder design and manufacturing process

Compared with other seals, it has the following characteristics: 1. Good sealing performance and long service life; a single ring can seal in both directions; 2. Good adaptability to oil, temperature and pressure; 3. Small dynamic friction resistance; small size, light weight and low cost; 4. The sealing part has a simple structure and is easy to disassemble and assemble; 5. It can be used for both static sealing and dynamic sealing; 6. The dimensions and grooves have been standardized, making selection and outsourcing easy. Its disadvantages: when the dynamic seal is started, the friction resistance is large, about 3 to 4 times the dynamic friction force, and it is easy to be squeezed into the gap under high pressure. The following points should be considered when selecting O-ring materials: 1. The working status of the O-ring refers to whether the O-ring is used for static sealing, dynamic sealing or sliding sealing; 2. The working status of the machine refers to whether the machine is working continuously or intermittently, taking into account the length of each intermittent time and whether there is an impact load acting on the sealing part; 3. The situation of working medium: whether the working medium is gas or liquid, and its physical and chemical properties should be considered; 4. Working pressure, pressure amplitude, fluctuation amplitude and frequency, and the maximum instantaneous pressure, etc.; 5. Working temperature includes instantaneous temperature and alternating hot and cold temperatures; 6. Price and source. Generally speaking, nitrile rubber is used for oil resistance, chloroprene rubber is used for ozone resistance, acrylate rubber or fluororubber is used for heat resistance, polyurethane rubber is used for high pressure resistance and wear resistance, and copolychlorohydrin rubber is used for cold resistance and oil resistance.