Special lecture on moving equipment "Pump", learn some knowledge every day (7) Seal "enrich yourself"”

This post was last edited by tclz007 on 2013-12-9 18:54 Someone asked me just now about the knowledge of packing sealing. I will attach it here~~! 　　Packing seals have the characteristics of wide sources of fillers, easy processing, low prices, reliable sealing, and simple operation, so they have a wide range of applications. In recent years, with the development of sealing packing, packing seals have been greatly improved in terms of materials, structural forms and various characteristics. Therefore, packing seals have been more widely used in the machinery industry and have achieved good economic benefits. 　　 1. Working mechanism of packing seals In the machinery industry, packing seals are mainly used as dynamic seals. It is commonly used as a rotating shaft seal for centrifugal pumps, compressors, vacuum pumps, and mixers. When designing and selecting a packing seal, the working conditions of the mechanical equipment should be the main consideration. The following conditions should be considered when selecting the packing.: 　　1. It has certain plasticity and can generate a certain radial force under the action of pressing force and make contact with the tight shaft. 　　2. It has sufficient chemical stability and does not pollute the medium. The filler will not be swollen by the medium. The impregnating agent in the filler will not be dissolved by the medium. The filler itself will not corrode the sealing surface. 　　3. The filler has good self-lubricating performance, wear resistance and small friction coefficient. 　　4. When there is a small amount of deviation in the shaft, the packing should have sufficient floating elasticity. 　　5. Simple manufacturing and convenient filling. For this reason, the compression degree of the filler needs to be adjusted frequently so that after the lubricant in the filler is lost after running for a period of time, some lubricant will be squeezed out, and at the same time, the relaxation of the compression force caused by the volume change of the filler will be compensated. Of course, squeezing the filler frequently will eventually exhaust the impregnating agent, so regular replacement of the filler is necessary. In addition, in order to maintain the liquid film and take away frictional heat, it is also necessary to intentionally allow a small amount of leakage at the packing. 　　 2. Problems with packing in the use of water pumps The shaft seal of water pumps generally uses oil-impregnated asbestos packing or oil-impregnated cotton yarn packing. Oil-impregnated asbestos packing has the advantages of heat resistance, good flexibility, and high strength, but it also has fatal shortcomings.: After braiding, the surface is rough, the friction coefficient is large, and there is leakage. In addition, the lubricant soaked in for a long time is easy to lose. Oil-impregnated cotton yarn packing will become very hard when soaked in water for a long time, and due to its large expansion coefficient, the friction will be large. In actual production, this situation often occurs: When the newly repaired equipment started operating, the shaft seal was in good condition. However, after a short time, the amount of leakage continued to increase, and the work of adjusting the gland and replacing the packing gradually became more frequent. In less than one cycle of operation, the shaft sleeve was worn into a vase shape. In severe cases, the shaft sleeve was worn out, and the packing behind the water seal ring that could not be replaced was rotted and could not function as a seal. 　　In general, packing has the following disadvantages: (1) The packing is in direct contact with the shaft and rotates relative to it, causing wear of the shaft and the sleeve, so the sleeve must be replaced regularly or irregularly. (2) In order to dissipate the friction heat generated between the packing and the shaft or sleeve in time, the packing seal must maintain a certain amount of leakage, and it is difficult to control. (3) The friction between the packing and the shaft or bushing reduces the effective power of the motor and consumes electric energy, sometimes even reaching an astonishing proportion of 5%-10%. Generally speaking, packing has the following disadvantages:: From the perspective of the principle of packing sealing, there are three channels through which fluid can leak in the sealing chamber.: One is that the fluid penetrates the fiber material and causes leakage; the other is leakage from between the packing and the packing box; the third is leakage from between the packing and the shaft surface. Therefore, the most critical measure to prevent water pump leakage is: (1) Reasonably select the sealing packing; (2) Design a reasonable sealing cavity and adjust the appropriate sealing pressure. 　　 3. Design of combined soft packing seal The designed packing cavity structure is shown in Figure 2. The packing cavity is filled with an excellent sealing soft material, which is composed of carbon fiber, high-purity graphite, polytetrafluoroethylene, organic sealant, etc. It has a heat resistance of -18°C to 200°C, a maximum pressure of 0.7Mpa, a maximum linear speed of 8m/s, strong corrosion resistance, and a suitable medium pH value ranging from 4 to 13. It is mainly suitable for water media. This soft filler is in a clay-like state, with low friction coefficient and small molecular attraction between the mixture. 　　During the operation of the shaft, the fibers in the filler will wrap around the shaft and rotate with the shaft to form a "rotating layer". This "rotating layer" plays a role in protecting the shaft or sleeve, avoiding sleeve wear and reducing power consumption; as the diameter of the "rotating layer" gradually increases , the fiber winding ability of the shaft will gradually weaken, it will not wrap around the shaft, and remain relatively stationary with the inner wall of the packing cavity, forming a "shear layer" in the packing cavity. At this time, the friction and shear area of relative rotation exists in the middle of the packing instead of between the packing and the shaft. In addition, the polytetrafluoroethylene braided filler is pressed into both ends of the injected filler, and the mixed soft filler is compressed using the end rings of the braided filler. In order to prevent the mixed soft filler from being extruded and thrown out during the high-speed rotation of the shaft, spiral grooves are specially designed and processed in the filler cavity and gland. It is worth noting that the directions of the spiral grooves at both ends of the filler should be opposite to each other. This ensures that the mixed filler is pumped inward when the shaft rotates, effectively preventing the splash of the filler. 　　 4. Water pump test situation After the design and production of the combined packing is completed, the test is carried out on the water pump test bench. The design conditions of the test bench are as follows:: The motor speed is 1500r/min, the working pressure is 1MPa, the medium is clean water, and the medium temperature is normal temperature. 　　The packing filling process is carried out as follows (1) Clean the packing cavity, check whether there are scratches, burrs, etc. on the shaft surface, and ensure that the roughness of the shaft reaches Ra1.6 as required by the drawing; (2) Use a dial indicator to check the radial runout of the shaft at the sealing part, and its tolerance should be within the range of 0.03mm-0.08mm. (3) When filling the braided PTFE end ring, it is best to first take a wooden rod of the same size as the shaft, wrap the braided PTFE around the wooden rod, and then cut it with a knife. The cut should be a 45-degree slope. Use a wooden half sleeve with the same size as the packing cavity and fit it on the shaft to push the braided packing into the depth of the cavity. Use a gland to apply a certain pressure on the wooden sleeve to pre-compress it. Pay attention to keep the braided packing flat at the bottom of the cavity. (4) When injecting mixed clay-like filling, it must be pressed with a wooden bushing while injecting. Finally, braided polytetrafluoroethylene is used to press the outside of the filling cavity. Tighten the gland evenly and rotate the main shaft by hand at the same time so that the compressing force after filling tends to be parabolic. Then relax the gland slightly and the filling is completed. Carry out the operation test. When the operation is just started, the leakage is mainly intermittent dripping. When the leakage increases, tighten the gland bolts appropriately. If the heat is too great, loosen the bolts. After normal operation, the leakage basically stopped. After 60 hours of trial operation, the packing seal cavity was opened for observation. The shape of the braided PTFE end ring remained intact, the mixed soft packing did not fall out, and there was no sign of wear on the shaft. 5. Conclusion 1. The combined soft packing effectively improves the mechanical efficiency of the pump and reduces wear on the shaft. Because the packing gland can remain leak-free for a long time, it protects the environment. 　　2. Maintenance is convenient. When leakage is large, packing can be injected without stopping work, which extends the continuous working time of the pump and saves labor and maintenance costs. According to preliminary estimates, the energy consumption saved per pump can save tens of thousands of yuan per year. 　　3. Combined soft filler has broad application value. The following is the special lecture "Pump" of my special series of dynamic equipment. 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Please support, listen and discuss ； If you have any directions that need introduction, please contact me. If there are many requests, I will make a special post to explain~~! :) A series of special lectures on moving equipment "Pumps", a summary of the knowledge learned every day, and will be updated continuously. http://bbs.hcbbs.com/thread-1256318-1-1.html Welcome everyone to come and listen. I have already broadcasted. I hope that people like me who want to gain knowledge every day will listen. Let’s learn together every day. * , discuss~~!

It would be even better if the seniors attached pictures to explain.

Don't call me senior. . . Everyone learns together * ~~!

I don’t know much about the machine seal model. I wonder if there is any information on this!

This post was last edited by tclz007 at 2013-11-29 10:45 Mechanical seal model and applicable scope Mechanical seal model: Type 103　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -45～200℃ □Rotation speed: ≤3000r/min □Medium: Gasoline, kerosene, diesel, wax oil, heavy oil, lubricating oil, propylene, benzene, phenol, pyridine, ether, dilute nitric acid, concentrated sulfuric acid, acetic acid, urea, alkali, sea water, etc. 　　 Mechanical seal model: Type 103B　　■: Scope of application□Pressure: 0～1MPa□Temperature: -80～200℃ □Rotation speed: ≤3000r/min □Medium: River water, sewage, sea water, oil, solvents and medium corrosive media. 　　□Formal features: Built-in unbalanced single spring parallel coil spring transmission. 　　 □Mechanical seal model: Type 104　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -45～200℃ □Rotation speed: ≤3000r/min □Medium: Gasoline, kerosene, diesel, wax oil, heavy oil, lubricating oil, propylene, benzene, phenol, pyridine, ether, dilute nitric acid, concentrated sulfuric acid, acetic acid, urea, alkali, sea water, etc. 　　 Mechanical seal model: Type 105　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -20～200℃ □Rotation speed: ≤3000r/min □Shaft diameter: 35 ~ 120 □ Medium: Oils, benzene, phenol, dilute nitric acid. 　　□Formal features: Type 105 is a built-in, single-end, small spring, unbalanced, screw-driven mechanical seal for pumps. Comply with JB14752-75 standard. 　　 Mechanical seal model: Type 108　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: 0～120℃ □Rotation speed: ≤3000r/min □ Medium: Weak acid, weak alkali and other general corrosive media. 　　□Formal features: Built-in, single-end, spring-driven, unbalanced type. The rotation direction of the spring is related to the rotation direction of the pump shaft. 　　 Mechanical seal model: Type 109　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -45～200℃ □Rotation speed: ≤3000r/min □Medium: Gasoline, kerosene, diesel, wax oil, heavy oil, lubricating oil, propylene, benzene, phenol, pyridine, ether, dilute nitric acid, concentrated sulfuric acid, acetic acid, urea, alkali, sea water, etc. 　　 Mechanical seal model: Type 110　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -45～200℃ □Rotation speed: ≤3000r/min □Medium: Gasoline, kerosene, diesel, wax oil, heavy oil, lubricating oil, propylene, benzene, phenol, pyridine, ether, dilute nitric acid, concentrated sulfuric acid, acetic acid, urea, alkali, sea water, etc. 　　 Mechanical seal model: Type 114　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: 0～200℃ □Rotation speed: ≤3000r/min □Shaft diameter: 22～70□Medium: Concentrated sulfuric acid, dilute sulfuric acid, phosphate alkali. 　　□Formal features: Type 114 is an externally mounted, shift fork transmission type, and its dimensions comply with JB1472-75 standard mechanical seal models.: Type 116U　　■: Scope of application□Specifications: Ф24～Ф120mm □Pressure: 0～0.8MPa □Temperature: -20℃～120℃ □Impurities: ≤5wt%. 　　medium: Gasoline, kerosene, diesel, wax oil, heavy oil, lubricating oil, propylene, benzene, phenol, pyridine, ether, dilute nitric acid, concentrated sulfuric acid, acetic acid, urea, alkali, seawater and other mechanical seal models: Type 117U　　■: Scope of application□Specifications: Ф24～Ф120mm □Pressure: 0～0.8MPa □Temperature: -20～120℃ □Impurities: ≤5wt%. 　　 □Mechanical seal model: Type 119B　　■: Scope of application□Pressure: 0～1.2MPa □Temperature: 0～150℃ □Speed: ≤20m/s □Form features: The seal is a built-in, single-end multi-spring, driven pin driven balanced mechanical seal. The seal complies with DIN24960, ISO3069 and GB6556 standards and is widely used in weak acid, weak alkali, water, oil and other solutions. 　　 Mechanical seal model: Type 152　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: 0～120℃ □Rotation speed: ≤3000r/min(25m/s) □Medium: Weakly acidic particle-free medium. 　　□Formal features: Multi-spring exterior, PTFE bellows type, single end face, uniform installation length. 　　 Mechanical seal model: Type 153　　■: Scope of application□Pressure: = 2MPa □Temperature: -20～150℃ □Rotation speed: ≤3000r/min □Medium: Sea water, oil, weak acid, weak alkali. 　　□Formal features: Built-in, single-end, parallel-coil spring transmission balanced type, the spring rotates left and right. 　　 Mechanical seal model: Type 157　　■: Scope of application□Pressure: = 1MPa □Temperature: -45～200℃ □Rotation speed: ≤3000r/min □Medium: Sea water, oil, weak acid, weak alkali. 　　□Formal features: Built-in, single-end, parallel-coil spring-driven unbalanced seal, the spring rotates left and right. 　　 Mechanical seal model: Type 152B　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: 0～120℃ □Rotation speed: ≤3000r/min(25m/s) □Medium: Weakly acidic particle-free medium. 　　□Formal features: Multi-spring exterior, PTFE bellows type, single end face, uniform installation length. 　　 Mechanical seal model: Type 153　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: 0～80℃ □Rotation speed: ≤3000r/min □Medium: Various concentrations of sulfuric acid, hydrochloric acid, phosphoric acid, dilute nitric acid and other highly corrosive media. 　　□Formal features: Internal external flow type, multi-spring, single-end bellows static type. 　　 Mechanical seal model: Type 160　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: 0～120℃ □Rotation speed: ≤3000r/min □Medium: Contains particles, crystallized acid, alkali, salt, sea water, gas, flammable and explosive, etc. 　　□Formal features: Built-in double-end large spring, unbalanced type, transmission sleeve transmission. 　　 Mechanical seal model: Type 169　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: 0～150℃ □Rotation speed: ≤3000r/min □Medium: A strong base containing crystalline particles. 　　□Formal features: Equipped with multi-spring and bellows automatic balancing type. The friction material is made of cemented carbide, which is especially suitable for media containing crystalline particles. 　　 Mechanical seal model: Type 171　　■: Scope of application□Pressure: 0～1.2MPa □Temperature: 0～150℃ □Rotation speed: ≤20m/s □Form features: The seal is a built-in, single-end, multi-spring static balanced mechanical seal that complies with GB6556 standards and is widely used in alkali pumps. 　　 Mechanical seal model: Type 202　　■: Scope of application□Pressure: 0.11～0.25MPa □Temperature: -40～250℃ □Rotation speed: ≤500r/min □Shaft diameter: 30～110mm □Media: Various weakly acidic gases. 　　 Mechanical seal model: Type 204　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: 0～180℃ □Rotation speed: ≤500r/min □Medium: Acid, alkali, oil, polymer suspension. 　　 Mechanical seal model: Type 206　　■: Scope of application□Pressure: 0.6～1.6MPa □Temperature: -40～250℃ □Rotation speed: ≤500r/min □Shaft diameter: 30～110mm □Media: Reactor shaft seals for flammable, explosive, highly corrosive, particle-laden, low-temperature media and vacuum. 　　 Mechanical seal model: Type 212　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: -45～180℃ □Rotation speed: ≤500r/min □Medium: Type 212 is suitable for various highly corrosive gases without suspended particles except light fluoric acid. 　　□Formal features: Type 212 is a single-end outflow small spring polyfluoroethylene bellows balanced type, with a mechanical seal for the kettle. Especially suitable for enameled stirring shafts. 　　 Mechanical seal model: Type 224　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -20～150℃ □Rotation speed: ≤3000r/min □Medium: Weak acid and weak alkali liquid. 　　□Formal features: Double end face, small spring, transmission sleeve transmission, unbalanced, corrosion-resistant mechanical seal. 　　□illustrate: This product needs to be cooled and flushed and circulated as quickly as possible. A reasonable friction pair can be selected according to the working conditions. Mechanical seal model that can work stably and reliably for a long time when used in conjunction with ISO2858 chemical pumps: Type 59B　　■: Scope of application□Pressure: 0～5MPa □Temperature: -50～250℃ □Rotation speed: ≤5000r/min □Medium: Oil, water, organic solvents and other weakly corrosive solvents. 　　□Formal features: Type 59B seal has a balanced multi-spring structure, small axial size, and even pressure on the sealing end face. A wedge-shaped ring made of polytetrafluoroethylene or flexible graphite is used as the auxiliary sealing ring, which has a compact structure and reliable sealing. 　　 Mechanical seal model: Type 59U　　■: Scope of application□Pressure: 0～1MPa□Temperature: -50～250℃ □Rotation speed: ≤3000r/min(25m/s) □Medium: Weakly acidic particle-free medium. 　　□Formal features: Multi-spring exterior, PTFE bellows type, single end face, uniform installation length. 　　 Mechanical seal model: BIA type　　■: Scope of application□Pressure: ≤9.8 X 105MPa □Temperature: -20～80℃(NBR);-20～150℃(Fluorine rubber) □Speed ​​speed: ≤3000r/min □Medium: Oil, water, weakly corrosive liquids. 　　□Formal features: BIA type rubber bellows mechanical seal is an internal installation and internal flow structure. Its transmission form is that the rubber bellows and the shaft drive the moving ring to rotate coaxially through the fastening force of the fastening seat. BIA type machinery complies with DIN24900 standard. The structure is simple and compact, and can be matched with IS pump. 　　 Mechanical seal model: EX type　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: -45～80℃ □Linear speed: ≤15m/s □Medium: 2EX weakly corrosive liquids containing a small amount of particle impurities; 3EX weakly alkaline liquids (weakly corrosive, no particles); 4EX acidic liquids (weakly corrosive, no particles); 5EX lubricants, gasoline, kerosene, water and other non-corrosive liquids without impurity particles. 　　 Mechanical seal model: FBD type　　■: Scope of application□Pressure: 0～0.8Mpa □Temperature: -20～80℃(NBR);-20～150℃(Fluorine rubber) □Speed ​​speed: ≤3000r/min □Medium: Oil, water and other weakly acidic solutions. 　　□use: Suitable for sealing the rotating shafts of pumps, compressors and other similar equipment. 　　 Mechanical seal model: FO1D type　　■: Scope of application□Pressure: 0～0.7MPa □Temperature: -20～140℃ □Rotation speed: ≤3000r/min □Medium: Weak acid, weak alkali and other general corrosive media. 　　□Formal features: Type FOV1D is an interior-mounted, internal-flow, single-end structure. 　　 Mechanical seal model: FO2D type　　■: Scope of application□Pressure: 0～0.7MPa □Temperature: -20～80℃(NBR);-20～150℃(Fluorine rubber) □Speed ​​speed: ≤3000r/min □Medium: Oil, water, organic solvents and other weakly corrosive solvents. 　　□Formal features: The medium suitable for this product is allowed to contain particles and precipitated solid crystals. When the auxiliary sealing ring is made of fluorine rubber, it can withstand higher medium temperatures (200°C). However, in order to ensure the reliability of the assembly of the rotating ring and the stationary ring, the recommended operating temperature does not exceed 150°C. 　　 Mechanical seal model: GX type　　■: Scope of application□Pressure: 0～0.8MPa □Temperature: 0～80℃ □Rotation speed: ≤3000r/min □Shaft diameter: 25～100mm □Media: 1GX engine oil and gasoline; 2GX weak acid and weak alkali; 3GX and other small particulate impurities. 　　□Formal features: Type GX is an interior-mounted, single-end, sleeve-rotating, unbalanced type. 　　 Mechanical seal model: GY type　　■: Scope of application□Pressure: 0.8～4MPa□Temperature: 0～80℃ □Rotation speed: ≤3000r/min □Shaft diameter: 25～100mm □Media: 1GY engine oil and gasoline; 2GY weak acid and weak alkali; 3GY and other small particulate impurities. 　　□Formal features: Type GY is an internally mounted, single-end, sleeve-rotating, unbalanced type. 　　 Mechanical seal model: U(UK) type　　■: Scope of application□Pressure: 0～4MPa □Temperature: When the medium is water, 0 ~ 66℃; when other media are used, -73 ~ 204℃ □Rotational speed: ≤3000r/min □Medium: Oil, residual oil, water and various organic solvents. 　　□Formal features: Built-in, single spring, balanced type, driven by transmission pin; the rotating ring sealing ring adopts U-shaped sealing ring, which has good self-tightening performance, reliable sealing and stable performance. Different materials, different friction pair materials and structures can be selected according to different working conditions. It can also be cooled and flushed according to AP1610 standards. 　　 Mechanical seal model: WB2 type　　■: Scope of application□Pressure: 0～0.4MPa □Temperature: 0～150℃ □Rotation speed: ≤3000r/min □Medium: Strongly acidic, particle-free media. 　　□Formal features: Multiple springs and PTFE bellows type. 　　It’s just some mechanical seal models. There are so many types of models that it’s difficult to unify them~~!

study* Well, I haven’t come across such detailed information before.

I don’t know anything about these. I need to learn more from the teacher.* ah. I have listened to you and will learn from you when I have time * .

It's okay, study* Most of this kind of thing is accumulated over a long period of time. If you accumulate a little bit every day, you will gradually learn a lot of things that you don’t know. We can discuss it together.