CN111637228A - Mechanical seal static friction ring material for cryogenic pump - Google Patents
Mechanical seal static friction ring material for cryogenic pump Download PDFInfo
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- CN111637228A CN111637228A CN202010477923.1A CN202010477923A CN111637228A CN 111637228 A CN111637228 A CN 111637228A CN 202010477923 A CN202010477923 A CN 202010477923A CN 111637228 A CN111637228 A CN 111637228A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
- F16J15/3496—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member use of special materials
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Abstract
The invention belongs to the technical field of static friction ring materials, and discloses a mechanical seal static friction ring material for a low-temperature pump, which comprises the following components in percentage by weight: 15% -18% of glass fiber, 7% -10% of graphite and the balance of polytetrafluoroethylene. Compared with the static friction ring made of the existing material, the static friction ring made of the material disclosed by the invention has better wear resistance and longer service life in a low-temperature environment.
Description
Technical Field
The invention relates to a mechanical seal static friction ring material, in particular to a mechanical seal static friction ring material for a low-temperature pump.
Background
Mechanical seals for mechanical seal pumps are various in types and different in types. After the mechanical seal is installed and debugged, a static test is generally performed to observe the leakage rate. After the mechanical seal for the pump is subjected to static test, the leakage of the medium is suppressed by a centrifugal force generated by high-speed rotation during operation. Therefore, the leakage of the mechanical seal during test operation is basically caused by the damage of the friction pair of the moving ring and the static ring after the shaft clearance and the failure of the end cover seal are eliminated.
The main factors causing the sealing failure of the friction pair are:
1. the excessive compression amount during the installation of the mechanical seal causes serious abrasion and scratch of the end surface of the friction pair;
2. the sealing ring of the movable ring is too tight, and the spring cannot adjust the axial floating amount of the movable ring;
3. the static ring sealing ring is too loose, and when the movable ring axially floats, the static ring is separated from the static ring seat;
4. the working medium contains granular substances, and people enter a friction pair during operation to detect the flaw of the sealing end faces of the movable ring and the static ring;
5. the design has errors, the specific pressure of the sealing end surface is low or the cold shrinkage of the sealing material is large, and the like;
6. failure due to loss of the lubricating film on the two sealing end faces;
7. dry friction occurs when the pump is started when the seal cavity is short of liquid due to the presence of end face seal load;
8. the pressure of the medium is lower than the saturated vapor pressure of the medium, so that the end surface liquid film is subjected to flash evaporation and loses lubrication;
9. failure of the mechanical seal due to corrosion. The sealing surface pitting and even penetration. Because the tungsten carbide ring is welded with the stainless steel seat, the stainless steel seat is easy to generate intergranular corrosion during use; the welded metal bellows, springs, etc. are susceptible to cracking under the combined action of stress and corrosion of the medium.
10. Mechanical seal failure due to high temperature effects. Under the conditions that impurities enter the sealing surface, are evacuated and the like due to dry friction and sudden interruption of cooling water at the sealing surface, radial cracks can occur on the ring surface; graphite charring is one of the main causes of seal failure when carbon-graphite rings are used. When the graphite ring is used, if the temperature of the graphite ring exceeds the allowable temperature (generally minus 105-250 ℃), resin can be separated out from the surface of the graphite ring, the resin near a friction surface can be carbonized, and when a binder is present, the resin can be foamed and softened, so that the leakage of a sealing surface is increased, and the sealing fails; the auxiliary sealing element, such as fluororubber, ethylene propylene rubber and full rubber, will age, crack, harden and lose elasticity rapidly after exceeding the allowable temperature. The flexible graphite used at present has better high temperature resistance and corrosion resistance, but has poor rebound resilience. And is fragile and easily damaged during installation.
11. Failure of the seal due to wear of the seal face. The friction pair is made of a material with poor wear resistance, a large friction coefficient, an excessively large end face specific pressure (including a spring specific pressure), and the like, so that the service life of the mechanical seal is shortened. For commonly used materials, the order of the wear resistance is: silicon carbide-carbon graphite, hard alloy-carbon graphite, ceramic-carbon graphite, spraying ceramic-carbon graphite, silicon nitride ceramic-carbon graphite, high-speed steel-carbon graphite and surfacing hard alloy-carbon graphite. For media containing solid particles, the ingress of the seal face into the solid particles is the primary cause of seal failure. Solid particles enter the end face of the friction pair to play a role of grinding agent, so that the seal is severely abraded and loses efficacy. For the petrochemical industry, the selection of mechanical seal for high-temperature heavy oil pump has been a big problem, such as catalytic cracking oil slurry pump, recycle oil pump, atmospheric tower bottom pump, preliminary distillation tower bottom pump, vacuum tower bottom pump, delayed coking radiation charge pump, etc. The media, temperature and pressure of various pumps (generally, the pressure of flushing liquid is required to be higher than the pressure of the medium side by 0.07-0.12 MPa) are different, the structure of an external flushing system is more complicated, and in addition, the investment of external flushing facilities and the consumption of maintenance cost sometimes cause more defects, and particularly, a group of sealing end surfaces of small and medium-sized enterprises close to the impeller is in a hard-to-hard structure (such as YG6-YG 6); one group of sealing end faces close to the mechanical sealing gland can be made of copper or antimony-impregnated carbon, namely graphite to tungsten carbide or silicon carbide; the isolating medium selected for the high-temperature oil pump has the characteristics of high thermal decomposition temperature, self-ignition point, high flash point (generally above 260 ℃), good thermal oxidation stability and small high-temperature evaporation loss. The mechanical seal for the liquid hydrocarbon pump selects a liquid hydrocarbon medium which is a low-temperature liquefied gas and has the characteristics of low boiling point, low viscosity, high vapor pressure and the like. The mechanical seal applied under the working condition can cause the sealing material to have cold brittleness, water vapor in the atmosphere can be frozen on the atmosphere side surface of the sealing device, a liquid film on the end surface of the friction pair is easy to vaporize, and the like. Especially, when the medium slightly leaks, leaked liquid hydrocarbon immediately vaporizes at the atmosphere side to carry away a large amount of heat, the temperature of the mechanical sealing environment is sharply reduced, and the common sealing material such as rubber or polytetrafluoroethylene generally becomes brittle to cause sealing failure, and the leakage is increased and cannot be picked up.
Some enterprises use double mechanical seals with a separate chamber between the media and atmosphere, which is filled with a sealing oil to mitigate the effects of low temperatures. However, this structure is complicated and requires a sealing liquid system. The soft material for mechanical seal mainly comprises: graphite. There are two different types of sintered graphite: carbon graphite and electrographite. The former is hard and brittle, the latter is soft, low in strength and good in self-lubricating property. Graphite has good self-lubricity and good thermal conductivity, has good corrosion resistance but is not resistant to strong oxidizing media, has thermal shock resistance and a low friction factor. However, graphite has disadvantages of large porosity and low mechanical strength. Therefore, when graphite is used as a soft-surface material, it is necessary to fill the pores by impregnation or the like to improve the mechanical strength.
With the rapid development of petrochemical and air separation industries, cryogenic liquids are being widely used in various chemical processes and technological processes, and therefore cryogenic liquid transfer pumps become key equipment for these processes. The most important difficulty of the cryogenic pump is that the shaft seal of the pump is very difficult to solve due to the limitation of cryogenic materials, the easy vaporization of working liquid and other factors. The cryopump is a single-stage cantilever centrifugal pump. The pump is an acetylene tower reflux pump, the working medium is ethylene, the function of the pump is to control the tower top not to contain C3 component in the previous flow, and the pump is simply called an ethylene cryogenic pump because the working temperature is-54 ℃. The pump has the problems of serious mechanical seal leakage, high maintenance frequency of the pump, short operation time and great influence on production. The pump working at ultralow temperature is always in a state of conveying saturated liquid, and cavitation and vibration are easily caused due to vaporization of working liquid; the deposition of particles and impurities can make the dynamic and static rings of mechanical seal lose floatability and the spring fail. More seriously, the particles and impurities entering the friction pair can increase the abrasion of the friction pair, and the mechanical seal is rapidly damaged. Therefore, the mechanical seal must be designed with consideration for its floatability and followability. The mechanical seal of the low-temperature light hydrocarbon pump belongs to a series single-end-face mechanical seal in contact type mechanical seals, a medium end adopts the traditional contact type mechanical seal, and a sealing medium is light hydrocarbon (the components are complex, C3-C10); the methanol end is also sealed by traditional contact type machinery, and the sealing medium is methanol. The single-end contact type mechanical seal of the light hydrocarbon pump does not have a complete liquid film between the sealing end surfaces. The large amount of friction heat generated between the sealing end faces can cause the temperature of the sealing faces to rise, thereby promoting the vaporization of liquid films between the end faces and the change of the liquid into vapor to generate phase change. In addition, since the saturated vapor pressure of the light hydrocarbon medium is higher than one atmosphere pressure, the light hydrocarbon medium generates pressure reduction when flowing through the seal end face gap, and is inevitably vaporized (phase-changed) at a certain position. So that the fluid film phase can be divided into liquid phase sealing, gas phase sealing and gas-liquid phase mixed sealing according to the end face fluid film phase. The operating characteristics of the sealing device are very different, usually under different fluid film conditions. The liquid phase is filled with a complete liquid film between the sealing end faces, and leakage may occur in the form of liquid or gas. A layer of mixed film formed by liquid and vapor is filled between the sealing end faces of the gas-liquid mixed phase seal, and leakage appears in a gas phase mode. The sealing device is characterized in that the film pressure coefficient changes along with different temperatures, the working state is unstable, obvious phenomena of air jet vibration, end face squealing and the like are easy to occur, the friction and the abrasion of the sealing end face are serious, and early failure is easy to occur. Therefore, the service life thereof is short. When the temperature rise of the sealing end surface is too high to completely vaporize the end surface liquid film or when the process operation condition fluctuates to vaporize the medium in the sealing cavity (namely the medium pressure in the sealing cavity is lower than the vaporization pressure at the temperature), the end surfaces are in an all-gas film state, although the gas film is a stable gas film, the sealing end surface is in a dry friction contact state, a large amount of friction heat is generated, and the temperature of the end surfaces is rapidly increased. If strong temperature regulation measures such as flushing and cooling are not adopted or the process operation is immediately stabilized, the sealing surface is seriously burned, and the end surface of the sealing alloy ring can fail due to heat cracking. The main sealing ring of the mechanical seal is made of silicon rubber, the auxiliary seal is made of nitrile rubber, and the silicon rubber of the main sealing ring is not suitable for a medium (C3-C10) component and is easy to cause swelling corrosion, so that the main seal fails; the auxiliary sealing ring is made of nitrile rubber, the temperature application range is-30-120 ℃, but the working temperature is usually lower than-30 ℃ due to complex components of sealing media, process fluctuation and the like, the lowest working temperature can reach-52 ℃, when the main seal has trace leakage, the leaked media enter a methanol cavity, and the temperature of the entered media is lower than the lowest temperature which can be borne by the nitrile rubber, so that the auxiliary sealing ring fails. The liquid film counter force is an important factor influencing the specific pressure of the mechanical seal end face, the seal end face is seriously abraded and short in service life when the specific pressure of the end face is too large, and the seal leakage is serious to fail due to the fact that the specific pressure of the end face is too small. In the mechanical seal used under the condition of normal design working condition, the moving ring of the mechanical seal is compressed by the resultant force of the medium and the spring, and the size of the pressing force has great influence on the service life of the mechanical seal. The specific pressure of the selected end surface is too large, so that the friction surface is heated, the abrasion is intensified and the power consumption is increased; the specific pressure is too low, leakage is easy, and sealing failure is caused. The friction pair is made of hard-hard material. The alkane, alum, copper sulfate, potassium sulfate and glycerol solvent can dissolve the sealing ring and destroy the filling material in the graphite. The mechanical seal is broken due to shaft wobble, which is more pronounced on the graphite ring. In addition, the contact between the mechanical seal and the shaft (or shaft sleeve) can be corroded, eroded and abraded locally due to the excessive axial string quantity. The static friction ring of the mechanical seal for the cryogenic pump (liquid oxygen, liquid nitrogen and liquid argon) needs super-strong wear resistance under the low-temperature environment of 196 ℃ below zero to ensure the service life of the mechanical seal, the wear time of the current domestic materials is 2-3 months, the wear time of the foreign imported materials is 5-6 months, and the composite material with the wear time of 8-10 months is developed through technical improvement.
Disclosure of Invention
The invention provides a mechanical seal static friction ring material for a cryogenic pump, aiming at solving the problem that a mechanical seal static friction ring of the cryogenic pump in the prior art is fast in abrasion, and the material can still keep super-strong abrasion resistance in a low-temperature environment.
The material provided by the invention only consists of 15-18% of polytetrafluoroethylene, 7-10% of glass fiber and the balance of graphite, and still has super-strong wear resistance in a low-temperature environment. The mechanical seal static friction ring processed by the material has the mechanical seal service life longer than 8 months, so the problems of low wear resistance and short mechanical seal service life of the mechanical seal static friction ring in the low-temperature environment in the prior art are solved.
Moreover, the material provided by the invention can be used for processing the mechanical seal static friction ring of the cryogenic pump and can also be used for processing the mechanical seal static friction ring of the cryogenic pump. The mechanical seal static friction ring of the ultralow temperature pump processed by the material still has higher wear resistance in a low temperature environment of 196 ℃ below zero.
The invention is realized by the following technical scheme:
a mechanical seal static friction ring material for a low-temperature pump only consists of polytetrafluoroethylene, glass fiber and electrographite; the composite material comprises, by weight, 15% -18% of glass fibers, 7% -10% of graphite oxide, and the balance of polytetrafluoroethylene.
In the formula of the material, polytetrafluoroethylene is used as a main component, and glass fiber and electrochemical graphite are mixed filling materials. The polytetrafluoroethylene has good corrosion resistance, high heat resistance and cold resistance, good self-lubricating property and dynamic and static friction factors lower than 0.04. However, polytetrafluoroethylene has poor thermal conductivity, and glass fibers and graphite are mixed and filled in order to modify polytetrafluoroethylene.
The electrochemical graphite can be used for working conditions of high speed, high load and ultralow temperature. The sealing device has the advantages of good sealing performance, long service life, small friction loss, reliable operation, good relative economy, and good sealing effect in eliminating 'running, overflowing, dripping and leaking'. No or little leakage occurs over a longer service life, and the mechanical seal leaks about 1/10 with a stuffing seal. The electrochemical graphite has good self-lubricating property, good thermal conductivity, good corrosion resistance, thermal shock resistance, low friction factor and long service life. The used mechanical seal can continuously run for 1-1.5 years or longer, and under normal working conditions, maintenance is not needed in the service cycle, so that the labor intensity of workers can be greatly reduced; the friction power loss is small. The frictional power loss of the mechanical seal is about 5-10% of that of the packing seal. The auxiliary sealing ring is resistant to low-temperature aging and has certain elasticity; the sealing surface has good lubrication, and a liquid film on the sealing surface is prevented from vaporizing; cold insulation or isolation from the atmosphere.
The glass fiber is an inorganic non-metallic material with excellent performance. The components are silicon dioxide, aluminum oxide, calcium oxide, boron oxide, magnesium oxide, sodium oxide and the like. It has high heat resistance, can be used below 1050 ℃ for a long time, can resist the high temperature up to 1700 ℃ instantly, and has the temperature resistance second to that of carbon fiber. The glass fiber is used as a polytetrafluoroethylene reinforcing material and is characterized by high tensile strength. High heat resistance, high corrosion resistance and high mechanical strength. The tensile strength is 6.3-6.9 g/d in the standard state and 5.4-5.8 g/d in the wet state. The density was 2.54g/cm 3. The novel hair-dyeing and-weaving process is characterized in that glass balls or waste glass is used as a raw material and is manufactured through processes of high-temperature melting, wire drawing, winding, weaving and the like, the diameter of each monofilament ranges from several micrometers to twenty micrometers, the diameter of each monofilament is equivalent to 1/20-1/5 of one hair, and each fiber strand consists of hundreds of monofilaments and even thousands of monofilaments. After filamentation, the strength of the composite material is greatly increased, the composite material has flexibility, good adhesion with resin, higher temperature resistance than organic fiber, non-combustibility, corrosion resistance, heat insulation and high tensile strength.
The glass fiber is a high-strength material, the wear resistance of the polytetrafluoroethylene and the electrographite is enhanced by adding the glass fiber, the short glass fiber is filled to fill the pores of the mixture of the polytetrafluoroethylene and the graphite, the mechanical strength is improved, the defects of large porosity and low mechanical strength of the graphite are overcome, the heat-resisting temperature of the polytetrafluoroethylene is enhanced, the temperature is greatly improved compared with that before the glass fiber is not added, the wear resistance is greatly enhanced, the stress cracking is avoided, and meanwhile, the impact resistance is greatly improved. Due to the addition of the glass fiber, the tensile strength, the compressive strength and the bending strength are greatly improved after the glass fiber is reinforced.
Based on the above formula, four typical specific formulas are preferred in the invention:
firstly, according to weight percentage, the mechanical seal static friction ring material for the cryogenic pump consists of 15 percent of glass fiber, 7 percent of graphite and 78 percent of polytetrafluoroethylene;
secondly, according to weight percentage, the mechanical seal static friction ring material for the cryogenic pump consists of 16 percent of glass fiber, 10 percent of graphite and 74 percent of polytetrafluoroethylene;
thirdly, according to weight percentage, the mechanical seal static friction ring material for the low-temperature pump consists of 17 percent of glass fiber, 7 percent of electrochemical graphite and 76 percent of polytetrafluoroethylene;
fourthly, according to weight percentage, the mechanical seal static friction ring material for the cryogenic pump consists of 18 percent of glass fiber, 10 percent of electrochemical graphite and 72 percent of polytetrafluoroethylene.
Further, in order to better realize the invention, the glass fiber is specifically quartz glass fiber with the length of 0.3mm-1 mm.
The material is used for manufacturing a mechanical seal static friction ring of a cryogenic liquid pump. The machined mechanical seal static friction ring has high mechanical strength, good pressure resistance, good dry abrasion resistance, high load resistance, good self-lubricating property, good heat conductivity, good heat dissipation, good thermal cracking resistance and strong corrosion resistance; the linear expansion coefficient is small, the heat resistance and the dimensional stability are good, the running-in property with a matched material is good, and excessive abrasion and dual corrosion are avoided.
The invention also provides a mechanical seal static friction ring material for the low-temperature pump, which only consists of polytetrafluoroethylene, glass fiber and impregnated graphite; the glass fiber-impregnated graphite comprises 15-18 wt% of glass fiber, 7-10 wt% of impregnated graphite and the balance polytetrafluoroethylene.
Further, in order to better implement the present invention, the impregnated graphite is resin-impregnated graphite or metal-impregnated graphite.
Further, in order to better implement the present invention, when resin-impregnated graphite is used, specifically, any one of phenol resin-impregnated graphite, epoxy resin-impregnated graphite, and furan resin-impregnated graphite is used.
Further, in order to better implement the present invention, when the impregnated metal graphite is used, specifically, any one of impregnated babbitt metal graphite, impregnated copper alloy graphite, impregnated aluminum alloy graphite, and impregnated antimony alloy graphite is used.
Further, in order to better implement the present invention, the glass fiber is specifically quartz glass fiber.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the mechanical seal static friction ring for the low-temperature pump, which is processed by the material, can still keep super-strong wear resistance in a low-temperature environment;
(2) the mechanical seal static friction ring for the cryogenic pump, which is processed by the material, has no strict requirements on precooling and the like of the cryogenic pump, and the failure rate is obviously reduced; meanwhile, the problems that the mechanical seal main seal is damaged and the service life is short due to the fact that a medium in the low-temperature pump is easy to volatilize and poor in lubricity are solved;
(3) in the invention, the electrochemical graphite and the quartz glass fiber with the length of 0.3mm-1mm are particularly selected to improve the thermal conductivity, the lubricity and the wear resistance of the material.
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Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Example 1:
the invention is realized by the following technical scheme that the mechanical seal static friction ring material for the low-temperature pump only consists of polytetrafluoroethylene, glass fiber and electrographite; the composite material comprises, by weight, 15% -18% of glass fibers, 7% -10% of graphite oxide, and the balance of polytetrafluoroethylene.
In this embodiment, the electrochemical graphite is particularly selected and has good thermal conductivity and self-lubricity.
The embodiment discloses a mechanical seal static friction ring material for a low-temperature pump, which takes polytetrafluoroethylene as a main component and is filled with quartz glass fiber and electrochemical graphite according to the weight proportion. The composite material prepared by the formula has super-strong wear resistance in low-temperature environments such as liquid oxygen, liquid nitrogen, liquid argon and the like, and the service life of the mechanical seal of the cryogenic pump can be greatly prolonged by preparing the friction ring.
Example 2:
the present embodiment is further optimized based on embodiment 1, and the glass fiber is specifically quartz glass fiber with a length of 0.3mm-1 mm.
The glass fiber with the length of 0.3mm-1mm can play a role in reinforcement: the glass fiber is too short, so that the glass fiber only has the filling effect and the reinforcing performance is wasted; the glass fiber is too long, the interface combination between the glass fiber and the material is not good, the reinforcing effect of the glass fiber is influenced, the surface of the product is too rough and not smooth enough, and the surface performance is not good.
In the present embodiment, the length of the glass fiber is particularly limited to 0.3mm to 1mm to improve the tensile strength.
Further, the length of the glass fiber selected in this embodiment is between 0.4mm and 0.8 mm. The closer this figure is to the median value, the better the wear resistance.
Furthermore, SiO is selected as the glass fiber in the present embodiment2Content (wt.)>99.99% of quartz glass fiber product, and the impregnating compound for the glass fiber is HT 1. HT1 is a high temperature resistant sizing agent, is an organic ceramic-based sizing agent, and can enhance the temperature resistance of fabrics and keep the good performance of quartz glass fibers at 1050-1200 ℃.
Other parts of this embodiment are the same as those of the above embodiment, and thus are not described again.
Example 3:
the present embodiment is further optimized based on embodiment 1 or embodiment 2.
In the embodiment, according to the components specified in table 1, glass fibers with any specific value of 15-18% are filled in polytetrafluoroethylene according to weight percentage, then, electrochemical graphite with any specific value of 7-10% is added for mixing, and after stirring for 1-2 hours, the mixture is pressed and sintered to obtain the mechanical seal static friction ring material for the low-temperature pump.
TABLE 1
Specifically, four groups of specific formulas are selected:
a first group: according to weight percentage, the mechanical seal static friction ring material for the low-temperature pump consists of 15 percent of glass fiber, 7 percent of graphite and 78 percent of polytetrafluoroethylene;
second group: according to weight percentage, the mechanical seal static friction ring material for the low-temperature pump consists of 16 percent of glass fiber, 10 percent of graphite and 74 percent of polytetrafluoroethylene;
third group: according to weight percentage, the mechanical seal static friction ring material for the low-temperature pump consists of 17 percent of glass fiber, 7 percent of graphite and 76 percent of polytetrafluoroethylene;
and a fourth group: according to weight percentage, the mechanical seal static friction ring material for the low-temperature pump consists of 18% of glass fiber, 10% of graphite and 72% of polytetrafluoroethylene.
As shown in Table 1, the materials prepared by the four formulations were tested for wear resistance and life at-196 deg.C. The detection of the wear resistance is obtained by detecting the size variation after running tests are carried out on the mechanical seal of the cryogenic pump by using produced parts. The friction loss of the static friction ring prepared by the four groups of formulas at a low temperature of 196 ℃ below zero is less than 0.002mm each time. Moreover, the static friction ring prepared by the four groups of formulas has the reduced service life of 8.2-9.1 months. Therefore, the static friction ring made of the material prepared by mixing 15-18% of glass fiber and 7-10% of graphite through polytetrafluoroethylene has better wear resistance and longer service life in a low-temperature environment compared with the static friction ring made of the existing material.
Other parts of this embodiment are the same as those of embodiment 1 or embodiment 2, and thus are not described again.
The foregoing is illustrative of the preferred embodiments of the present invention and is not to be construed as limiting thereof in any way. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in other forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed manner, including employing various features disclosed herein in combination with features that may not be explicitly disclosed herein. Various changes and modifications in the above-described arrangements and materials, including combinations of features disclosed herein either individually or in any combination thereof, will be apparent to those skilled in the art upon examination of the principles of the invention. These variations and/or combinations fall within the technical field related to the invention and the protective scope of the invention as claimed.
Claims (10)
1. The mechanical seal static friction ring material for the cryogenic pump is characterized in that: the components by weight percentage are as follows: 15% -18% of glass fiber, 7% -10% of graphite and the balance of polytetrafluoroethylene.
2. The mechanical seal static friction ring material for the cryogenic pump according to claim 1, wherein: the components by weight percentage are as follows: 15% of glass fiber, 7% of electrochemical graphite and 78% of polytetrafluoroethylene.
3. The mechanical seal static friction ring material for the cryogenic pump according to claim 1, wherein: the components by weight percentage are as follows: 16% of glass fiber, 10% of electrochemical graphite and 74% of polytetrafluoroethylene.
4. The mechanical seal static friction ring material for the cryogenic pump according to claim 1, wherein: the components by weight percentage are as follows: 17% of glass fiber, 7% of electrochemical graphite and 76% of polytetrafluoroethylene.
5. The mechanical seal static friction ring material for the cryogenic pump according to claim 1, wherein: the components by weight percentage are as follows: 18% of glass fiber, 10% of electrochemical graphite and 72% of polytetrafluoroethylene.
6. The mechanical seal static friction ring material for the cryogenic pump according to any one of claims 1 to 5, wherein: the glass fiber is quartz glass fiber with the length of 0.3mm-1 mm.
7. The mechanical seal static friction ring material for the cryogenic pump is characterized in that: the components by weight percentage are as follows: 15% -18% of glass fiber, 7% -10% of impregnated graphite and the balance of polytetrafluoroethylene.
8. The mechanical seal static friction ring material for the cryogenic pump according to claim 7, wherein: the impregnated graphite is impregnated resin graphite or impregnated metal graphite.
9. The mechanical seal static friction ring material for the cryogenic pump according to claim 8, wherein: when the impregnated resin graphite is used, specifically, any one of phenol resin impregnated graphite, epoxy resin impregnated graphite, and furan resin impregnated graphite is used.
10. The mechanical seal static friction ring material for the cryogenic pump according to claim 8, wherein: when the impregnated metal graphite is used, any one of impregnated babbitt metal graphite, impregnated copper alloy graphite, impregnated aluminum alloy graphite and impregnated antimony alloy graphite is specifically used.
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| CN204459158U (en) * | 2015-01-06 | 2015-07-08 | 镇江润方密封件有限公司 | A kind of teflon rotating ring |
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Application publication date: 20200908 |