The seal preventsfluidorsolidParticles from adjacentJunction surfaceMaterials or materials that may leak or prevent foreign matters such as dust and moisture from invading the internal parts of machines and equipmentspare parts。The room temperature of seals should be below 30 ℃ to avoid high temperature aging.
Although rubber and plastic seals are small, their functions make themnational defense、chemical industry、petroleum, coal, transportation, machinery manufacturing and other major industries in the national economy, basic components and accessories play a very important role in the development of the national economy.In recent years, with the rapid economic growth, rubber and plastic seal manufacturing industry has maintained double-digit growth.The data shows that in 2011, the scale of China's rubber and plastic seal manufacturing industry (the above enterprises (according to the statistical caliber of the National Bureau of Statistics, the sales revenue is more than 20 million yuan) achieved a total industrial output value of nearly 10 billion yuan, with a year-on-year growth of more than 20%.There are more than 150 enterprises with an annual income of 20 million yuan in the rubber and plastic seal manufacturing industry in China, and the domestic rubber seal industry as a whole presents a development situation of small enterprise scale and low technical level.From the perspective of enterprise economic type, private enterprises and foreign-funded enterprises account for more than 95%, which is the main economic type of the industry;At the same time, enterprises are basically concentrated in East China. In terms of the number of enterprises, sales revenue and asset scale, East China has occupied a considerable share, with a high degree of market concentration.
1. It is better to store the seals at a room temperature below 30 ℃ to avoid high-temperature aging of seals;2. Seals must be stored in sealed packages to avoid contact with moisture or dust in the air;3. Seals must be kept away from strong light to avoid ozone corrosion in the air or early aging.The factors affecting the performance of various seals are different, such asMechanical seal(packing seal, etc.)temperature, medium, wear, pressure, etc.
Key points for use
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(1) Select appropriate seal material and hydraulic oil, as well as adaptability to working temperature and oil compatibility.(2) The geometric position accuracy (concentricity) of the sliding parts relative to the seals is high and the materials are good (such as hard chrome plating) andSurface roughnessSlim can prolong service life. ①For the oil seal used for hydraulic pump and motor journal, not only the roughness of the sliding surface is required to be within 0.25m Ra, but also the surface is required to be plated with hard chrome. During specific use, the radial spring force of the oil seal lip needs to be properly adjusted according to the specific situation to make it moderately tight. In addition, during installation, an installation sleeve or thin gasket should be used to protect the seal ring to prevent the lip from rolling and twisting,Causes the spring to slip out. ②The common rolling processing method for the inner surface of hydraulic cylinder barrel not only improves the surface roughness, but also makes its surface undergo cold work hardening treatment, which is conducive to extending the service life of the seal ring.In addition, the pressure used, the length and type of sliding surface also have a great impact on the service life.Therefore, the "regular inspection" time should be determined according to these conditions. ③Sealing surface requiredlubricationIt is in good condition to prevent dirt from invading people.It is also necessary to use the oil with the specified cleanliness level and correct installation method.
influence factor
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Hydraulic sealIt plays a vital role in the integration of hydraulic and pneumatic components. If the seals of a hydraulic and pneumatic component product are not qualified, then this hydraulic and pneumatic component product is not a good product.There are many factors affecting seals.First of all, pressure is an important reason that affects the quality of seals. The level of pressure and the length of pressure cycle change have a great impact on seal damage (such as extrusion).The higher the pressure, the greater the influence of other factors on the performance of the seal, such as temperature, speed, seal material, clearance between the piston and cylinder barrel, and clearance between the piston and cylinder head.Another is temperature and friction. It is difficult to describe the maximum and minimum service temperature of a seal material, because it is the result of a series of factors.As the working temperature of piston and piston rod are different, they should be selected differently.Another is that the surface roughness, surface characteristics, pressure, medium, temperature, seal material, seal type and movement speed of the seal are all factors that affect the seal.The last one is surface treatment. Experience shows that the characteristics of the surface of the cylinder piston and piston rod have a great impact on the life of the seals.Surface characteristics are usually defined by the value of surface roughness RA, which is the arithmetic mean of the absolute value of the surface shape deviation from the centerline.However, these values do not fully represent the impact of surface conditions on seals, because even under the same roughness, different surface shape characteristics can lead to different degrees of seal wear on seals.
matters needing attention
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1. Before designing the groove, please study and read the description of each series of products by yourself, and make it clear that the product uses the integral groove or split groove;During the installation of seals, attention shall be paid to avoiding sharp edges, and installation tools must be used to install the seals into the whole groove;The designer should take into account the parameters such as groove size accuracy, surface roughness, extrusion clearance, etc. Please refer to the product instructions, diagrams and dimension tables for details.2. Before installing the sealing element, ensure that there are no impurities and cracks in the sealing groove, and apply operating oil on the sealing groove and the surface of the sealing element respectively;Install the seals gradually in sequence;During installation, avoid sharp edges and straighten the seals to avoid distortion and skew;In case of split groove, finally tighten the gland.
Common name
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Seal ring, packing, mechanical sealoil seal、Water seal, packing, sealing pad, sealant, soft packing, hydraulic seal, pneumatic seal, etc.
Industry status
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In recent years, the production and quality of rubber sealing products in China has gradually entered a new stage and a new period.However, these alone are far from meeting the needs of other industries for the standardization and serialization of various rubber sealing products. Especially compared with the international advanced countries, China's products have a considerable gap in both product quality and product variety.This issue of the forum focused on the concept, research content and significance of sealing, reviewed the current situation of rubber and plastic seal, mechanical seal and packing seal technology, analyzed the gap between China and the world's advanced and developed sealing technology in research level and new product development capability, and put forward some suggestions on the future research focus in the field of sealing in China.
It is well known that the overall competitiveness of the sealing industry in China is not strong. In our country, the sealing industry can be said to be the smallest industry, but the products can be used with large industries.No matter aviation, navigation, petroleum, chemical industry, or machinery, power generation, metallurgy, mining, etc., are inseparable from seals.In a word, all organic, pump, pipe and valve parts depend on seals.So although the industry is small, it involves a wide range.In recent years, with the development of economy, the sealing industry has developed rapidly.But different from other industries, the sealing industry has developed rapidly, but the sealing enterprises have changed slowly.For example, in the late 1970s and early 1980s, there were only a few manufacturers in Jiangsu, Zhejiang and Shandong, and seal factories can be seen everywhere in the coastal, inland, southern and northern regions. The entire seal industry has grown from a few to as many as 300, which can be said to be a rapid development.However, as far as individual enterprises are concerned, many enterprises have not changed much, and their production scale has stagnated, some even regressed. The scientific and technological strength has not increased significantly, but some are weakening. Many manufacturers still cling to the "four old", namely, old products, old technology, old equipment, and old scale.Of course, there are some enterprises that have strong ability to imitate some products, but there are few enterprises that have the ability to independently develop new products in the whole industry.As far as products are concerned, most manufacturers still have some old products such as spiral wound gaskets, packing rings, packing and high-strength gaskets.The slightly innovative polytetrafluoroethylene products lag far behind foreign countries in technology and quality, such asPTFE packing, expansionPTFE tape 。Looking around, there are few new products.In terms of technical strength, the proportion of scientific and technological personnel in most enterprises is relatively small. Many enterprises lack technical personnel with professional background, and the technical strength is weak. Therefore, enterprises lack corresponding development and transformation capabilities.Since the establishment of the EU, the strength brought by the alliance has prompted the EU to improve and establish new European sealing quality standards, replacing the series of standards previously developed by the American Fluid Association.In the new European seal quality standard, leakage rate appears and is emphasized.The leakage rate of Chinese products is generally 10-1mg/s, while in Europe, there has been a high leakage rate of 10-4mg/sGraphite composite plate!As far as equipment is concerned, most enterprises only have a few old knitting machines, a few home-made winding machines, simple punching machines and shearing machines, which depend on the ability of old workers to organize production;However, the equipment of many manufacturers has been in the state of unsaturation of production tasks for a long time.In terms of quality management, the vast majority of enterprises rely on the proficiency of operators to do a good job of products, and do not produce in accordance with the standard process, which is also a necessary management means.Although many manufacturers have obtained ISO9000 series certification, their internal process documents, quality control plans or operation guidance documents and equipment management documents are often empty and weak, far from the international level.In terms of scale, the sales of most enterprises are below 5 million yuan, 10 million yuan is few, and more than 10 million yuan is few.Frankly speaking, most of the sales of many manufacturers are outsourced parts, and the proportion of their own production is not very high.So many small enterprises are difficult to compete with some famous foreign companies and manufacturers.
Analysis on the advantages and disadvantages of China's sealing industry in international peers To sum up, our sealing industry is weak in competitiveness, but this refers to some small enterprises, and we also have some strong companies or factories.Although there are several famous large enterprises abroad, there are also many small enterprises. There are also many commercial companies specializing in sealing business that buy products from China and sell them in their own countries or other countries. Therefore, the advantages and disadvantages of the whole international counterparts are different.In terms of advantages, we have advantages in three main aspects: raw material advantages, whether asbestos, graphite or othersNon metallic materialsWe are a big producer and many countries lack this resource.Price advantage Current seals orLabor intensive productsThe manufacturing cost in China is low (US: 1500 dollars/person month for operators; Japan: 200000 yuan/person month for young workers; 300000 yen for older workers; more than 1000 yuan/person month for us), and 60% of the victory in the current seal competition depends on the price factor.In the domestic market, the phenomenon of main engine matching (OEM form) is already obvious, especially in the international market.With the further deepening and improvement of domestic reform.Price plays an increasingly important role in the maintenance market.Humanistic advantages At present, the marketing of seals in the domestic market mainly depends on interpersonal relationships. Thanks to the unique combination of time and people, we have many advantages under the same quality conditions in the domestic market.From the perspective of market competition, with these three advantages, we can embark on the road of competition.
Conversely, disadvantages may be more
The first thing to bear the brunt is technological backwardness.On the one hand, in order to meet the increasing requirements of human beings for environmental protection,ISO14000 standardIt has begun to be valued by Chinese enterprises, and people have increasingly strict requirements for sealing.Just like the entry of a large number of joint ventures, it has brought new quality requirements and new environmental protection concepts.On the other hand, the new standard objectively brings about the redistribution of the market.The new and stricter quality standards will become the biggest obstacle to the export of China's sealing products;It has also become a killer weapon for foreign enterprises to enter the Chinese market.Enterprises that do not attach importance to technological progress will be eliminated in the next five years.The subject of technology is human.As far as the current situation is concerned, the sealing industry is relatively loose, and the individual scale is small, so the ability to hide the dragon and crouch the tiger is small, and the overall quality of enterprise employees is low.In addition, there may be a need for correct business philosophy.Capitalism has been around for more than 200 years, and many of our peers, namely competitors, have experienced four generations of continuity. They have already got rid of the mentality of seeking wealth from poverty to a well-off society, and have moved towards a mature mentality to do market, management, brand, and culture.The reason why our enterprises have so many repeated establishment at this stage is that many people are eager to seek wealth while taking advantage of various non-standard situations in the reform process.This is a natural process of alternation,capitalist countryI have the same experience.But what we have in front of us is how to accelerate the evolution from being eager for wealth and entrepreneurship to a mature business culture.On this basis, it is not difficult to see the various drawbacks in the individual behavior of our enterprises.Inadequate cooperation and increased competition result in market decline, which is the biggest problem in business.In fact, if you keep down the price and pursue orders, the market will be destroyed.The market is not a cake, but a field, which needs to be paid, nurtured, and cared for, so that there will be gains and lasting.In terms of quality awareness, after-sales service, product packaging, equipment investment and other aspects, the enterprises naturally have their own evaluations.Although there are "three points of technology, seven points of management" management problems, as long as you have confidence, it is still easy to improve.
