Product Introduction of Cylinder Liner Sealing Rings
The cylinder liner sealing ring is a static sealing accessory in the hydraulic end cylinder liner installation system of the drilling mud pump. It is mainly used to seal the fit clearance between the external installation part of the cylinder liner and the related structure of the hydraulic end, preventing the drilling fluid from leaking out from the cylinder liner installation interface during the operation of the mud pump.
In some F series and similar structure drilling mud pumps, the cylinder liner sealing ring is installed in the corresponding sealing cavity or positioning position of the wear-resistant plate. After the cylinder liner is inserted, it forms radial and axial fits with the sealing ring, and then maintains the specified assembly state through the cylinder liner flange, cylinder liner cover and related locking structures.
Although the cylinder liner sealing ring is relatively small in size, its working condition will directly affect the sealing reliability of the cylinder liner installation area. Mismatches in the specifications, cross-sectional shapes, installation directions, compression amounts or material selections of the sealing rings may all lead to early leakage, squeezing or abnormal wear.
The main function of the cylinder liner sealing ring
1. Sealing cylinder liner installation interface: The cylinder liner sealing ring is installed between the outside of the cylinder liner and the corresponding sealing structure at the hydraulic end to prevent the working medium from leaking out along the cylinder liner installation gap.
2. Establishing static sealing: Unlike piston sealing, the cylinder liner sealing ring does not rely on continuous reciprocating friction with the piston rod or piston to achieve sealing during normal operation. Its main task is to perform static sealing on the fixed installation part of the cylinder liner.
3. Adapt to assembly clearance: The elastic sealing material undergoes appropriate deformation within the specified assembly space, compensating for the tiny gaps between the sealing mating surfaces and maintaining effective sealing contact.
4. Work in coordination with the cylinder liner installation system: The cylinder liner sealing ring works together with the wear-resistant disc, cylinder liner, cylinder liner flange and cylinder liner clamping structure to maintain a stable installation and sealing state in the hydraulic end cylinder liner area.
Sealing working principle
After the cylinder liner sealing ring is installed in the specified sealing cavity or sealing groove, the cylinder liner is inserted to form the compression and contact state required by the design for the sealing ring, thereby establishing a sealing barrier between the outer circle of the cylinder liner and the surrounding fixed structure.
When the mud pump is in operation, the pressure at the hydraulic end acts on the cylinder liner and the sealing area. The sealing ring maintains effective contact with the relevant sealing surface by relying on its own elasticity, assembly compression and the pressure formed by the specific sealing structure.
The sealing ring is not the tighter it is pressed, the better. If the size of the sealing cavity, the cross-section of the sealing ring or the assembly compression amount is incorrect, it may cause the sealing ring to be overly squeezed, cut or abnormally deformed, which will instead reduce its service life.
The fit relationship with the wear-resistant plate
In the hydraulic end structure of the slurry pump with wear-resistant discs, the wear-resistant discs can be set with counterholes, steps or corresponding sealing positions for installing the cylinder liner sealing rings, providing a stable support and positioning foundation for the sealing rings.
Wear-resistant plate: It belongs to metal structural components and mainly undertakes the functions of protecting the installation surface, positioning, supporting and load transmission.
Cylinder liner sealing ring: It is a type of sealing component, mainly using its own elasticity and assembly compression to seal the leakage channel at the installation part of the cylinder liner.
If the sealing cavity of the wear-resistant disc has already suffered from severe erosion, corrosion, scratches or dimensional abnormalities, replacing the cylinder liner sealing ring alone may not completely solve the leakage problem.
The difference from piston seals
The cylinder liner sealing ring should not be classified in the same category as the piston rubber and piston seal of the mud pump and other vulnerable parts.
Cylinder liner sealing ring: Located at the external installation interface of the cylinder liner, it mainly serves as a static seal for the fixed mating parts.
Piston seal: Installed on the piston assembly, it moves back and forth at high speed with the piston within the cylinder liner. It is a dynamic seal that directly participates in the suction and discharge processes of the working chamber.
There are obvious differences between the two types of seals in terms of installation position, motion state, wear mechanism and selection parameters.
The cross-section matches the sealing cavity
When selecting a cylinder liner sealing ring, it is not advisable to measure only one outer diameter or inner diameter. The inner diameter, outer diameter, cross-sectional dimensions, cross-sectional profile of the sealing ring, as well as the diameter, width and depth of the corresponding sealing cavity should be confirmed simultaneously.
Different mud pumps may adopt different structural forms of cylinder liner seals. Therefore, it is not advisable to replace the originally designed dedicated cylinder liner seals with ordinary O-rings merely based on their similar dimensions.
For lip, irregular or combined seals with directionality, the installation direction and pressure-bearing direction should also be confirmed in accordance with the original equipment requirements to avoid reverse installation.
Compatibility of sealing materials with drilling fluids
The material of the cylinder liner sealing ring needs to be comprehensively considered in terms of working temperature, drilling fluid system, contact conditions with oil media, pressure conditions and the original equipment material specifications.
Different elastomers vary in terms of oil resistance, water resistance, temperature resistance, chemical medium resistance and resistance to permanent compression set. Therefore, it is not advisable to determine the specific material merely based on the color of the sealing ring, nor should the material grade be changed at will without technical basis.
Common Failures and Inspections
Common abnormalities of cylinder liner sealing rings include aging and hardening, decreased elasticity, permanent compression deformation, surface cuts, extrusion, tearing, local wear, and expansion or performance degradation caused by the action of the medium.
When disassembling and inspecting, not only the sealing ring itself should be checked, but also the external sealing mating surfaces of the cylinder liner, the sealing cavity of the wear-resistant disc, the positioning steps and the adjacent installation surfaces.
If the new cylinder liner sealing ring leaks again within a short period of time after installation, it is necessary to focus on checking whether the sealing cavity is worn or eroded, whether the sealing mating surface of the cylinder liner is scratched, whether the sealing specification is correct, and whether the cylinder liner is installed properly. The problem should not be simply solved by increasing the clamping force.
Key points for selection
When purchasing the sealing ring of the drilling mud pump cylinder liner, it is recommended to focus on confirming the following information:
1. Brand, series and specific model of mud pump;
2. Hydraulic end or hydraulic cylinder model;
3. Matching cylinder liner model and external sealing dimensions;
4. Matching wear-resistant plate model;
5. Inner and outer diameters of the sealing ring;
6. Cross-sectional dimensions and shapes of the sealing ring;
7. Diameter of the sealing cavity of the wear-resistant plate or installation part;
8. Width and depth of the sealed cavity;
9. Whether the sealing parts have requirements for the installation direction;
10. Drilling fluid system and working medium;
11. Working temperature and pressure conditions;
12. Original sealing materials or material requirements;
13. Original part number, physical sample or technical drawing.
Installation and Maintenance
Before installation, the sealing cavity of the wear-resistant disc, the external sealing mating surface of the cylinder liner and the adjacent installation area should be thoroughly cleaned to remove mud, rust, residues of old seals and metal particles.
Check whether there are burrs or sharp edges at the entrance of the sealing cavity and the installation position of the cylinder liner to prevent the sealing ring from being cut during the cylinder liner insertion process. The lubrication method for the assembly of sealing parts should be carried out in accordance with the corresponding maintenance requirements of the mud pump.
For special sealing rings with lip or direction requirements, the correct direction should be confirmed before installation. After installation, it is necessary to check whether the sealing ring has been twisted, flanged, pinched or partially stripped from the groove.
When replacing the cylinder liner or disassembling the cylinder liner system for maintenance, the condition of the cylinder liner sealing ring should be checked simultaneously. Seals that have shown obvious hardening, deformation, cutting or loss of elasticity should be replaced in accordance with the maintenance requirements.
Procurement Instructions
Juli Petroleum Drilling and Production Equipment Co., Ltd. provides cylinder liner sealing rings and hydraulic end cylinder liner system accessories for drilling mud pumps. The cylinder liner sealing ring is mainly used for static sealing at the external installation interface of the cylinder liner, and is used in conjunction with the cylinder liner, wear-resistant disc, cylinder liner flange and compression structure. There may be differences among various models of mud pumps in terms of the inner and outer diameters of the sealing rings, cross-sectional dimensions, cross-sectional shapes, materials, and the structure of the sealing cavity. When purchasing, it is recommended to provide the model of the mud pump, the model of the hydraulic end, the specification of the cylinder liner, the model of the wear-resistant disc, the original part number, the physical dimensions or technical drawings for matching verification.