I believe that through the previous introduction, you have a good understanding of the O-ring, but do you know what factors will affect the performance of the O-ring? Let the O-ring manufacturer take you to analyze, hoping to let you better understand the O-ring.
O-ring hardness: the hardness of O-ring material is the most important index to evaluate the sealing performance. The hardness of the O-ring determines the compression amount of the O-ring and the maximum allowable extrusion clearance of the groove. As the NBR seal of Shao A70 can meet most of the service conditions, the NBR of Shao A70 is generally provided without special instructions for the sealing materials.
O-ring extrusion clearance: the maximum allowable extrusion clearance Gmax is related to system pressure, O-ring section diameter and material hardness. Generally, the higher the working pressure is, the smaller the maximum allowable extrusion gap Gmax is. If the clearance g exceeds the allowable range, the O-ring will be extruded or even damaged.
Compression set: another index to evaluate the sealing performance of O-ring is the compression set of the selected material. Under the action of pressure, the O-ring, as an elastic element, produces elastic deformation. With the increase of pressure, permanent plastic deformation will also occur.
Pre compression amount of O-ring: the O-ring is installed in the groove. To ensure its sealing performance, an initial compression amount shall be reserved. For different applications, the amount of pre compression is different with respect to the section diameter W. Generally, it is about 15% - 30% in static seal and 9% - 25% in dynamic seal.
O-ring stretching and compression: when the O-ring is installed in the groove, it will be stretched or compressed. If the values of tension and compression are too large, the O-ring cross-section will increase or decrease excessively, because the cross-section diameter w will decrease about 0.5% corresponding to 1% tension. For the hole seal, the O-ring should be in the stretching state, and the maximum allowable stretching amount is 6%; for the shaft seal, the O-ring should be compressed along its circumference direction, and the maximum allowable circumference compression amount is 3%.
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