What is a sealing ring

What is a sealing ring?

The sealing ring is an annular cover composed of one or several parts, which is fixed on one ring or washer on the bearing and contacts with another ring or washer or forms a narrow labyrinth gap, which can prevent the leakage of lubricating oil and the invasion of foreign objects.

20210818015200 23009 - What is a sealing ring

Material of sealing ring

1. NBR nitrile rubber sealing ring
It is suitable for petroleum hydraulic oil, glycol hydraulic oil, diester lubricating oil, gasoline, water, silicon grease, silicon oil and other media. It is the most widely used and lowest cost rubber seal at present. It is not suitable for polar solvents, such as ketones, ozone, nitrohydrocarbons, MEK and chloroform. The general operating temperature range is – 40 ~ 120 ℃.
2HNBR hydrogenated nitrile rubber sealing ring
It has excellent corrosion resistance, tear resistance and compression deformation resistance, and has good ozone resistance, sunlight resistance and weather resistance. It has better wear resistance than nitrile rubber. It is applicable to washing machinery, automobile engine system and refrigeration system using new environment-friendly refrigerant R134a. It is not recommended to use in alcohol, ester or aromatic solutions. The general operating temperature range is – 40 ~ 150 ℃.
3SIL silicone rubber sealing ring
It has excellent heat resistance, cold resistance, ozone resistance and atmospheric aging resistance. It has good insulation performance. However, the tensile strength is worse than that of ordinary rubber and has no oil resistance. Suitable for household appliances such as electric water heater, electric iron, microwave oven, etc. It is also suitable for all kinds of articles in contact with human body, such as kettle, water dispenser, etc. It is not recommended to use in most concentrated solvents, oil products, concentrated acids and sodium hydroxide. The general operating temperature range is – 55 ~ 250 ℃.
4Viton fluororubber sealing ring
High temperature resistance is better than silicone rubber, with excellent weather resistance, ozone resistance and chemical resistance, but poor cold resistance. It is resistant to most oil products and solvents, especially acids, aliphatic hydrocarbons, aromatic hydrocarbons and animal and vegetable oils. It is suitable for sealing requirements of diesel engines, fuel systems and chemical plants. It is not recommended to use ketones, low molecular weight esters and mixtures containing nitrate. The general operating temperature range is – 20 ~ 250 ℃.
5FLS fluorosilicone rubber sealing ring
It has the advantages of fluorine rubber and silicone rubber, and has good oil resistance, solvent resistance, fuel oil resistance and high and low temperature resistance. It can resist the erosion of oxygenated compounds, solvents containing aromatic hydrocarbons and solvents containing chlorine. It is generally used for aviation, aerospace and military purposes. Exposure to ketones and brake oils is not recommended. The general operating temperature range is – 50 ~ 200 ℃.
6EPDM sealing ring
It has good weather resistance, ozone resistance, water resistance and chemical resistance. It can be used in alcohols and ketones, as well as sealing in high-temperature steam environment. It is suitable for sanitary equipment, automobile radiator and automobile braking system. It is not recommended for food use or exposure to mineral oil. The general operating temperature range is – 55 ~ 150 ℃.
7CR neoprene sealing ring
It has excellent resistance to sunlight and weather. It is not afraid of refrigerants such as dichlorodifluoromethane and ammonia. It is resistant to dilute acid and silicone grease lubricating oil, but it has a large expansion in mineral oil with low aniline point. It is easy to crystallize and harden at low temperature. It is suitable for various environments in contact with atmosphere, sunlight and ozone and various sealing links resistant to combustion and chemical corrosion. It is not recommended to use in strong acids, nitrohydrocarbons, esters, chloroform and ketone chemicals. The general operating temperature range is – 55 ~ 120 ℃.
8IIR butyl rubber sealing ring
Excellent air tightness, heat resistance, sunlight resistance, ozone resistance and good insulation performance; It has good resistance to polar solvents such as alcohols, ketones and esters, and can be exposed to animal and vegetable oils or oxides. Suitable for chemical resistant or vacuum equipment. It is not recommended to use with petroleum solvents, kerosene or aromatics. The general operating temperature range is – 50 ~ 110 ℃.
9ACM acrylic rubber sealing ring
It has excellent resistance to oil, high temperature resistance and weather resistance, but the mechanical strength, compression deformation rate and water resistance are slightly poor. It is generally used in automobile transmission system and power steering system. Not applicable to hot water, brake oil and phosphate. The general operating temperature range is – 25 ~ 170 ℃.
10NR natural rubber sealing ring
It has good wear resistance, elasticity, tensile strength and elongation. However, it is easy to age in the air and become sticky in case of heat. It is easy to expand and dissolve in mineral oil or gasoline. It is alkali resistant but not strong acid resistant. It is suitable for use in automotive brake oil, ethanol and other liquids with hydroxyl ions. The general operating temperature range is – 20 ~ 100 ℃.
11PU polyurethane rubber sealing ring
Polyurethane rubber has very good mechanical properties, and its wear resistance and high pressure resistance are much better than other rubber. Aging resistance, ozone resistance and oil resistance are also quite good, but it is easy to hydrolyze at high temperature. It is generally used for high-pressure and wear-resistant sealing links, such as hydraulic cylinders. The general operating temperature range is – 45 ~ 90 ℃.

Classification of sealing rings

V-ring

It is an elastic rubber sealing ring with axial action, which is used as a non pressure seal of the rotating shaft. The sealing lip has good mobility and adaptability, can compensate for large tolerance and angle deviation, can prevent internal grease or oil leakage, and can also prevent the invasion of external splash or dust.

O-ring

It is mainly used for static seal and reciprocating seal. When used for rotary motion sealing, it is only limited to low-speed rotary sealing device.

Rectangular sealing ring

It is generally installed in the groove with rectangular section on the outer circle or inner circle for sealing.

Y-shaped sealing ring

It is widely used in reciprocating sealing devices.
In addition, there is a spring tension (spring energy storage) sealing ring, which adds a spring into PTFE sealing material, including O-Spring, V-spring and U-spring.

YX type sealing ring for hole

Application: used for sealing the piston in reciprocating hydraulic cylinder. Scope of application: TPU: general hydraulic cylinder, general equipment hydraulic cylinder. CPU: hydraulic cylinder for construction machinery and oil cylinder for high temperature and high pressure. Material: Polyurethane TPU, CPU, rubber.
Product hardness: HS85 ± 2 ° a working temperature: TPU: – 40 ~ + 80 ℃ CPU: – 40 ~ + 120 ℃ working pressure: ≤ 32Mpa working medium: hydraulic oil and emulsion.

Retaining ring for YX hole

Product application: this standard is applicable to use with YX type sealing ring when the working pressure of oil cylinder is greater than 16MPa, or to protect the sealing ring when the oil cylinder is eccentrically stressed. Operating temperature: – 40 ~ + 100 ℃.
Working medium: hydraulic oil, emulsion and aquatic.

Products hardness: hs92 ± 5A.

Material: polytetrafluoroethylene.

YX type sealing ring for shaft

Application: used for sealing piston rod in reciprocating hydraulic cylinder. Scope of application: TPU: general hydraulic cylinder and general equipment hydraulic cylinder. CPU: hydraulic cylinder for construction machinery and oil cylinder for high temperature and high pressure.
Material: Polyurethane TPU, CPU, rubber

Product hardness: HS85 ± 2 °

Working temperature: TPU: – 40 ~ + 80 ℃ CPU: – 40 ~ + 120 ℃

Working pressure: ≤ 32Mpa
Working medium: hydraulic oil and emulsion.

YX type retaining ring for shaft

Product application: this standard is applicable to use with YX type sealing ring when the working pressure of oil cylinder is greater than 16MPa, or to protect the sealing ring when the oil cylinder is eccentrically stressed. Working temperature: – 40 ~ + 100 ℃
Working medium: hydraulic oil, emulsion and aquatic

Products hardness: hs92 ± 5A

Material: polytetrafluoroethylene according to enterprise standard

O-ring rubber seal

Product application: the O-type rubber sealing ring in this standard is applicable to hydraulic and pneumatic systems and various mechanical equipment and components. It plays a sealing role in static or moving state under the specified pressure, temperature and different liquid and gas media.

Working temperature: – 40 ~ + 230 ℃

Working pressure: < 10 ~ 220kg, f/cm
Working medium: air, water and oil

Product hardness: 40 ~ 85 ± 2A

Material: nitrile rubber, silicone rubber, fluorine rubber and ethylene propylene rubber

Retaining ring for O-ring seal

Product application: this standard is applicable to the use with O-ring when the oil cylinder pressure is greater than 10MPa.

Operating temperature: – 100 ~ 200 ℃
Working medium: hydraulic oil, emulsion, water

Material: polytetrafluoroethylene, suitable for gb1235-76 according to JB/ZQ4224-86

J-type frameless dust ring

Application: it is used to prevent dust at the exposed part of piston rod or valve rod in reciprocating oil cylinder and cylinder.

Scope of application: TPU: engineering machinery, general machinery, cylinder, various valves, etc.
CPU: oil cylinder of construction machinery and oil cylinder with poor working conditions.

Material: polyurethane, nitrile rubber, working temperature: – 40 ~ 120 ℃
Product hardness: HS80 ± 5A according to JB/T6657-1993
The sealing ring has excellent sealing performance and high working life. The working life of dynamic pressure sealing is 5-10 times higher than that of conventional rubber sealing products, up to dozens of times. Under some conditions, it can have the same life as the sealing matrix.
The friction resistance of the sealing ring is small, and the dynamic and static friction are equal, which is 1/2-1/4 of the friction of the “0” shaped rubber ring, which can eliminate the “crawling” phenomenon of movement at low speed and low pressure.
The sealing ring is highly wear-resistant and has the function of automatic elastic compensation after the sealing surface is worn.
The sealing ring has good self-lubricating performance. It can be used as oil-free lubrication seal.
The sealing ring has the advantages of simple structure and convenient installation.
Working pressure of sealing ring: 0-300mpa; Working speed: ≤ 15m/S; Operating temperature: – 55-250 ℃.
Applicable media of sealing ring: hydraulic oil, gas, water, mud, crude oil, emulsion, water glycol, acid, alkali, chemicals, etc.

Advantages of sealing ring

  • 1. The sealing ring shall have good sealing performance within the working pressure and certain temperature range, and can automatically improve the sealing performance with the increase of pressure.
  • 2. The friction between the sealing ring device and the moving parts shall be small and the friction coefficient shall be stable.
  • 3. The sealing ring has strong corrosion resistance, not easy to aging, long service life and good wear resistance. It can be automatically compensated to a certain extent after wear.
  • 4. Simple structure, convenient use and maintenance, so that the sealing ring has a longer service life.

Installation precautions

  • 1. Clean the installation position;
  • 2. Remove burrs during seal installation;
  • 3. Apply lubricant to the seal;
  • 4. Protect the sealing surface from damage;
  • 5. Review and confirm that the size of the seal is correct;
  • 6. Use corresponding tools to install the seals that need to be deformed.

Application scope of sealing ring

Hardware and plastics, water supply and drainage, HVAC, fire protection, pharmacy, ship, pipeline system, automobile, locomotive, various machinery, household appliances, electronics, toys, sports equipment, pneumatic components and sanitary ware, etc.

Development of seal ring industry

With the progress of science and technology, the development of various industries has been continuously improved. The mechanical seal industry is also growing steadily, and the seal ring market is also selling well. All enterprises continue to strengthen product technology upgrading, further improve production capacity and supply market demand. Many of them independently develop advanced equipment and new products to meet customer needs. For example, Taizhou diaopu rubber ribbon factory in Jiangsu Province has more than 30 varieties and specifications of butterfly valve sealing rings with an inner diameter of 50 to 700 mm. In addition, it also sells semi-finished rubber products to surrounding marine parts factories. The factory has domestic advanced kneading internal mixer, rubber cutter, open mixer and other equipment, including dozens of vulcanizers, which can provide customers with products in batch. In recent years, it has also developed fluororubber, silicone rubber, EPDM and nitrile rubber products.
Today, when the market development is on the rise, the development of the sealing ring industry should also have the same pace, keep up with the market dynamics and improve the market competitiveness.

  • 1. Cylinder, compressor piston ring, high-pressure oil seal and oil pump in various scientific instruments need special planning to meet the requirements.
  • 2. The selection of seals is very important. It is still necessary to contact the equipment itself for selection.
  • 3. The setback of media is relatively simple. We just need to pay attention to some special and small setbacks. For example, the oil cylinder of metallurgical work often uses water glycol and phosphate hydraulic oil. Sometimes, although the working temperature is not high, you should pay great attention to the selection of sealing materials. FKM should be selected when selecting the latter for hydraulic oil.
  • 4. As for pressure, it affects the method of seal to be selected. Generally speaking, the selection of rubber or PU seal for low and medium pressure will not have much frustration. However, a setback of impact pressure should be considered. For example, it is initiated in construction machinery. When it is closed, its impact pressure is far from the normal working pressure, so it will often choose impact and extrusion gap resistant HBY or SPGW with a pressure resistance of up to 70MPa as the main seal. PTFE combined seal is also a common choice.
  • 5. As for the temperature, like the sealing material, the working temperature of NBR material is generally planned to be – 40 ~ + 120 ℃. If it exceeds 120 ℃, FKM or even PTFE should be considered. Low temperature is rare. Generally speaking, cold resistant NBR should be considered under the condition of – 20 ~ – 40 ℃. General NBR materials will harden and cause leakage under low temperature environment. For example, railway locomotives often have such setbacks in winter in the north.
  • 6. The working conditions to be considered in the selection of seals generally include: temperature, pressure and medium. In addition, it is also necessary to contact the characteristics of the equipment to consider the selection of seals.
  • 7. For the selection of seals, it is necessary to consider the working condition premise, and then select the appropriate sealing method, sealing material and equipment planning.

Installation and use of sealing ring

Precautions for installation and use of sealing ring:

  • (1) Do not install in the wrong direction and damage the lip. If there is 50 on the lip μ Scars above M may cause obvious oil leakage.
  • (2) Prevent forced installation. Instead of hammering in, use a special tool to press the sealing ring into the seat hole, and then use a simple cylinder to protect the part where the lip passes through the spline. Before installation, apply some lubricating oil on the lip to facilitate installation and prevent burns during initial operation. Pay attention to cleaning.
  • (3) Prevent overdue use. The service life of rubber seals for dynamic seals is generally 3000 ~ 5000h, and new sealing rings should be replaced in time.
  • (4) Replace the sealing ring with the same size. The sealing ring with the same size shall be selected in strict accordance with the requirements of the manual, otherwise the compactness and other requirements cannot be guaranteed.
  • (5) Avoid using old sealing rings. When using a new sealing ring, carefully check its surface quality to ensure that it is free of defects such as small holes, protrusions, cracks and grooves, and has enough elasticity before use.
  • (6) During installation, all parts of the open hydraulic system shall be strictly cleaned first, and it is best to use special tools to prevent fingers from being scratched by sharp metal edges.
  • (7) When replacing the sealing ring, strictly check the sealing ring groove, remove dirt and polish the groove bottom.
  • (8) In order to prevent oil leakage caused by damage, it must be operated according to the regulations. At the same time, it is not allowed to overload the machine for a long time or put the machine in a harsh environment.

Failure mode of sealing ring

The sealing ring material can withstand high or low temperature, chemical corrosion, vibration, wear and movement. The elastomer can be selected according to the situation.
The sealing ring material can withstand temperatures as low as – 200 ℃ or as high as 250 + C. In the low-end market, almost all engineering materials become rigid and can not be sealed; In the high-end market, the material is usually burned or decomposed. Chemical attack on degradable materials, starting brittle cracks or causing them to expand. For example, nitrile rubber seals can crack when exposed to gases with very low ozone concentration unless protected. The increased size caused by swelling by contacting with a low viscous fluid and also reduces the tensile strength of the rubber. Other faults can be caused by using the wrong size of the ring in a specific groove, which may lead to extrusion of the rubber.
Elastomers are sensitive to ionizing radiation. In a typical application, the seal ring is well protected, less penetrating radiation such as ultraviolet and soft X-rays, but more penetrating radiation such as neutrons may lead to rapid deterioration. In such an environment, the use of soft metal seals.

Precautions for sealing ring

  • 1. Clean the installation position;
  • 2. Remove burrs during seal installation;
  • 3. Apply lubricant to the seal;
  • 4. Protect the sealing surface from damage;
  • 5. Recheck and confirm that the size of the seal is correct;
  • 6. Use corresponding tools to install the seals that need to be deformed.

Source: China Sealing Ring Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

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