What factors should be considered when choose rubber seals?

- Jul 12, 2019-

Rubber seal products have a wide range of applications, which are related to the working medium and working conditions, the operating speed, hardness, sealing gap and form characteristics of the seal products.

1. Rubber seals used as rotating shaft seal operating speed

In terms of operating speed, the rubber seal can also be used as a low-speed rotary motion and a short-running rotary shaft seal. When the low-speed rubber seal is selected, it can be selected according to the normal design standard; when the rotational speed is 0.5m/s, it must be considered after the elongation. When the heat shrinks, the seal with a larger inner diameter is selected. After the sealing ring is installed in the groove, the sealing ring is radially compressed, and the rubber sealing ring forms a slight corrugation in the gully, thereby improving the lubrication condition.

2. Working medium and working conditions

When selecting a rubber seal material, the compatibility with the working medium should first be considered. Secondly, it is necessary to comprehensively consider the working conditions such as pressure, temperature, continuous working time and operating cycle of the seal. If used in a rotating situation, the temperature rise due to frictional heat should be considered. Different sealing materials have different physical properties and chemical properties.

3. The hardness of DSH rubber seals

The hardness of the rubber seal material is an important indicator for evaluating the sealing performance. The hardness of the rubber seal determines the amount of compression of the rubber seal and the larger groove allows the extrusion gap.

4. Sealed form

According to the type of load, it can be divided into static seal and dynamic seal; according to the sealing use, it can be divided into hole seal, shaft seal and rotary shaft seal; according to its installation form, it can be divided into radial installation and axial installation. For radial mounting, the shaft seal shall be such that the deviation between the inner diameter of the rubber seal and the diameter d2 to be sealed is as small as possible; for the seal of the hole, the inner diameter should be equal to or slightly smaller than the diameter d1 of the groove.

5. Extrusion gap

The basic clearance condition of the rubber seal is related to the system pressure and is related to the cross-sectional diameter of the rubber seal and the material hardness. Generally, the higher the working pressure, the larger the allowable value of the extrusion gap is. The exceeding the standard range directly leads to the damage of the rubber seal.