?Xinhua Xu Hydraulic O-ring Caution

??Hydraulic O-ring from the shape of the product to check whether the deformation, hydraulic O-ring will be deformed into a distorted shape, the inner diameter of the O-ring hydraulic whether deburring outer diameter burr-free, pollution-free surface, whether you want to apply to lubricating grease or lubricating liquid.

??Check hydraulic tensile hardness amount whether the O-ring to ensure the normal operation of the machinery required to consider whether the material compatibility with the operating medium, it must also consider the pressure seal, temperature, continuous working hours, operating cycle, etc. working conditions. If in a rotating case, shall consider the temperature rise due to friction caused by heat. Different seal material, its physical and chemical properties are not the same, see the "rubber seal material properties table."

??Xinhua Xu Hydraulic O-ring according to the load can be divided into static seal and dynamic seal; use can be divided according to the sealing hole seal, shaft seal and rotary shaft seal; its installation in the form of installation can be divided into radial and axial to install. Radial installation, the shaft seal, O-ring should make the hydraulic seal and the inner diameter of the deviation d2 between the diameter as small as possible; for holes

??Hydraulic O-ring material hardness is the most important indicator of assessment sealing performance. Hydraulic O-ring hardness determines the amount of compression and the O-ring groove hydraulic maximum permissible extrusion gap. Because Shaw A70 nitrile seals can meet most of the conditions, so as to make the sealing material is not specified, generally provided Shore A70 nitrile rubber.

??The maximum permissible extrusion gap gmax and system pressure, hydraulic O-ring cross-section diameter and hardness of the material. Generally, the higher the operating pressure, the maximum allowable extruding space gmax smaller value. If the gap g exceeds the allowable range, it will lead to even out the hydraulic O-ring damage assessment Another indicator O-ring seal hydraulic performance of the chosen material that is compressed permanent deformation.

??Hydraulic O-ring installed in the groove in order to ensure the sealing performance, should be reserved for an initial amount of compression. For different applications, different with respect to the pre-compression of the cross-sectional diameter W.

??Subject to tension or compression. If the tension and compression value is too large, will lead to excessive hydraulic O-ring cross section increases or decreases, because stretching makes 1% correspondingly reduced cross-sectional diameter of about 0.5 W%. For the hole sealed, preferably hydraulic O-ring in a stretched state, the maximum allowable amount of stretching is 6%; for shaft seals, hydraulic O-ring is preferably compressed along its circumference direction, the maximum allowable amount of compression perimeter 3%.

??Hydraulic O-rings may be used as the low-speed rotational movement and a shorter operating cycle rotary shaft seal. When the peripheral speed is less than 0.5m / s, hydraulic O-ring selection according to the normal design criteria; when the circumferential speed is greater than 0.5m / s, will be considered after the shrinkage phenomenon heated elongated rubber ring, so choose seal ring inner diameter than the shaft diameter to be sealed it about 2% larger, the above phenomenon can be avoided. After the seal is installed in the groove, resulting in seal by radial compression, hydraulic O-ring groove formed in micro corrugated canal, thereby improving the lubrication conditions.

??When installed, the compressive force with an initial degree of compression and the hardness of the material, illustrated as the relationship between units per centimeter perimeter seal on the compression force and the cross-sectional diameter between the total force required to estimate the size of the O-ring hydraulic installation .