How do sealing rings check and prevent oil leakage?

How to check the causes and troubleshooting methods of oil leakage from Sealing elements. Let's take a look together!

1. Excessive sealing clearance
The sealing gap is too large, and the O-Ring is squeezed into the sealing gap under pressure, as shown in Figure 1. In this way, the sealing gap is too large, and the Sealing ring is damaged under pressure. So, what is the appropriate sealing clearance for the sealing ring? Generally, the greater the pressure, the smaller the sealing clearance requirement. When the pressure is small, the sealing clearance is generally taken as 0.14~0.25 mm. The greater the pressure, the smaller the sealing clearance requirement, typically 0.08 to 0.14 mm. When the general working pressure P>100 kgf/cm2, a retaining ring should be added to the pressure bearing surface of the O-ring.

2. Incorrect Seal installation

1. The edges and corners, keyways, or through holes of accessories that scratch the sealing ring can easily cause leakage. The correct method is to round off the edges and corners to avoid scratching the sealing ring. Generally, the end can be chamfered at 15 ° to 30 °,

2. The sealing ring is easily damaged when passing through the thread, and should be installed with a special metal guide sleeve to avoid direct contact between the sealing ring and the thread,
3. If the sealing ring is twisted during installation, it can easily be damaged during operation, and must be removed and reinstalled. During installation, be sure to check whether the sealing ring is installed correctly.

3. Poor lubrication
The presence of a "critical oil film" at the edge of the Skeleton Oil Seal can reduce the wear of the edge of the skeleton Oil Seal, otherwise the skeleton oil seal will be burned due to dry friction caused by lack of oil. Generally, lithium based grease is used for lubrication. Ensure that the shaft surface skeleton oil seal is clean and lubricated. In order to prevent dust from entering the lips, a dust prevention device can also be added.

4. Wear
The service life of the sealing ring is generally 3000~5000 hours. If the sealing ring is used overtime, it should be replaced with a new sealing ring in a timely manner and ensure that the dimensions are consistent. When using a new sealing ring, it is also necessary to carefully inspect its surface quality to ensure that there are no defects such as small holes, bumps, cracks, and grooves, and that it has sufficient elasticity before use. During maintenance, select a sealing ring with the appropriate specification and size, use professional disassembly and assembly tools, and choose the correct lubrication and installation methods. Oil leakage from the sealing ring can be avoided.

5. Improper selection of sealing ring
Improper selection of sealing rings can lead to excessive looseness or tightness of the sealing rings during use, resulting in varying degrees of oil leakage from hydraulic components, resulting in increased or reduced compression of the sealing rings, leading to rapid damage to the sealing rings. What is the appropriate compression amount for the sealing ring? Generally, for flat flange fixed seals used in general equipment, the compression ratio should be 15% to 25%. For cylindrical fixed seals, the compression ratio should be 13% to 21%. For reciprocating seals, the compression ratio should be 10% to 12%. For Rotary Seals, the compression ratio should be 3% to 5%.

The common sealing elements of Hydraulic Seals include sealing rings, dust rings, bud shaped sealing rings, drum shaped sealing rings, etc. The sealing ring plays a key role in hydraulic transmission. Only when the sealing ring has excellent performance and no oil leakage is ensured in the hydraulic transmission can the hydraulic transmission operate normally.