HOW TO CHOOSE THE RIGHT SIZE O-RING FOR THE HYDRAULIC SYSTEM?

O-rings are suitable for various applications and different industries, both for the maintenance of old products and the design of new products. Do you know how to choose the right size O-ring for the hydraulic system?

The material of O-ring 

A variety of materials are available for O-rings, including nitrile rubber (NBR), EPDM (EPDM), fluorine rubber (FKM), silicone rubber (VMQ), etc.

Nitrile rubber (NBR) has excellent resistance to hydraulic oil and can be used in the temperature range of -35 ° C to + 120 ° C. It has excellent compression set resistance, tear resistance and abrasion resistance. O-rings made of nitrile rubber are usually the best choice for hydraulic applications.

Viton® O-rings have extremely high temperature resistance, grease resistance, fuel resistance, silicone oil resistance and resistance to many other media, such materials are very suitable for aviation applications.

Product Specifications of O-ring

There are several factors to consider when choosing the correct O-ring in a hydraulic system. The size of the O-ring is determined by the inner diameter, outer diameter and cross section. The lengths of the inner and outer diameters of O-rings are wide ranging from a few millimeters to one meter or more. When choosing the inner diameter of the O-ring, some space needs to be reserved to solve the thermal expansion problem.

The O-ring stretch rate should not exceed 5%, because over-stretching will cause the O-ring cross section to flatten. The variation range of the O-ring cross-section is small, ranging from a few millimeters to tens of millimeters. When selecting an O-ring for hydraulic applications, it is important to understand the depth of the groove. Only when the selected O-ring cross section is correct, it can avoid the occurrence of squeezing and tearing problems, and ensure the sealing effect.

Maximum pressure and operating temperature range of O-ring

Another important factor to consider when choosing the correct O-ring size is the maximum pressure and operating temperature range.

The maximum pressure is expressed in megapascals (MPa), and the operating temperature range is expressed in degrees Celsius. The maximum pressure of the O-ring material can be as high as 25 MPa, and the operating temperature range can vary from -40 ° C to + 200 ° C. When selecting an O-ring, its maximum pressure and working temperature cannot exceed its own limit. When the working condition exceeds its maximum pressure or working temperature range, it may damage the chemical resistance, flexibility, tear resistance, wear resistance, weather resistance and other properties of the O-ring.

In conclusion

When you choose the right O-ring for hydraulic applications, the inner diameter, outer diameter, cross section, material, maximum pressure and operating temperature range are all important parameters to consider. Retaining rings prevent extrusion in high-pressure applications, and star rings provide longer life for specific applications.

Although O-rings are very small and inexpensive components in hydraulic systems, they are critical to hydraulic performance and require careful selection. Carefully selecting a truly suitable O-ring will allow the hydraulic system to last longer. If you encounter any problems in purchasing sealing rings, please consult our professional sealing experts.