Product Introduction of Clamp Assembly
The clamp assembly is an important accessory in the piston transmission connection system of the drilling mud pump and is usually also called the piston rod clamp assembly. It is mainly installed between the power end and the hydraulic end, used to reliably connect the crosshead extension rod, the middle pull rod or the corresponding connecting rod with the piston rod, so that the reciprocating motion generated at the power end can be transmitted to the piston at the hydraulic end.
When the mud pump is in operation, the crosshead moves back and forth through the extension rod or the intermediate pull rod, and the clamp assembly connects it with the piston rod to form a continuous transmission chain. The piston rod further drives the piston to reciprocate inside the cylinder liner, completing the process of mud suction and discharge.
The common clamps of mud pumps adopt a two-half paired structure. The two half clamps are fastened by clamp bolts, and the internal formed grooves fit with the connection parts at the ends of the rods on both sides. Therefore, the inner groove size of the clamp, the pairing status of the two halves, and the end size of the rod all directly affect the connection reliability and the coaxiality of the transmission.
The main function of the clamp assembly
1. Connect the piston rod with the middle tie rod: Reliably connect the hydraulic end piston rod with the power end crosshead extension rod or the middle tie rod to establish the reciprocating transmission chain of the mud pump.
2. Transmitting reciprocating loads: During the operation of the mud pump, the connection part of the clamp needs to repeatedly bear periodic loads changing in the direction of tension and compression to ensure that the piston can continuously reciprocate with the power end.
3. Keep the connection parts centered: Through the precise fit between the inner groove of the clamp and the structures at the ends of the rods on both sides, maintain the correct axial position and center relationship between the piston rod and the middle tie rod.
4. Facilitates maintenance of the hydraulic end: After disassembling the clamp assembly, the piston rod can be separated from the power end connecting rod, providing conditions for the disassembly and replacement of the piston, cylinder liner and related hydraulic end parts.
Two-half clamp structure
The piston rod clamp of a drilling mud pump is usually composed of two half clamps. After the two halves are closed, an internal clamping groove that matches the connection structure at the rod end is formed, and then the clamping is completed through the clamp bolt.
Some of the clamps are processed as complete sets of parts during the manufacturing process. The two and a half clamps belong to a group that matches each other. After maintenance and disassembly, it is important to maintain the original pairing relationship. It is not advisable to mix and use half pieces of different clamp assemblies at will.
If there are significant differences in the inner grooves, mating surfaces or external dimensions of the two half clamps, it may cause incorrect closure, uneven clamping at the rod ends or offset of the connection center.
The fit between the inner groove and the end of the rod
The inner groove of the clamp is the key working part of this assembly, and its profile needs to be correctly matched with the connection structure at the end of the piston rod and the end of the crosshead extension rod or the middle tie rod.
The function of a clamp is not simply to rely on friction to "clamp" two round rods. In the specific structure of a mud pump, the inner trough, steps or corresponding formed surfaces, together with the rod end structure, jointly complete axial positioning and load transmission.
Therefore, when purchasing, it is not only necessary to measure the outer diameter of the clamp or the bolt hole, but also to carefully check the inner groove diameter, groove width, groove depth, internal contour and the connection dimensions of the rod ends on both sides.
The relationship with the piston rod and the intermediate tie rod
Piston rod: Located on one side of the hydraulic end, it is connected to the piston and drives the piston to reciprocate within the cylinder liner.
Crosshead extension rod/middle pull rod: Located on the power end side, it transmits the reciprocating motion of the crosshead to the hydraulic end.
Clamp assembly: Located at the connection position of the two, it reliably connects the above two rods and maintains the correct axial relationship.
Therefore, the clamp assembly belongs to the transmission connection parts of the mud pump, not the hydraulic end sealing parts, nor the ordinary pipeline fixing clamps.
Coaxiality and connection status
After the piston rod is connected to the middle tie rod, a good central relationship needs to be maintained. If the inner groove of the clamp is severely worn, the end size of the rod does not match, or the assembly of the two halves of the clamp is abnormal, it may cause the connection position to be skewed.
If the piston rod, piston, cylinder liner and related sealing and guiding parts are in an abnormal centering state for a long time, it may increase the eccentric load. Therefore, when replacing the clamp, the fit condition of both ends of the rod should be checked simultaneously.
Clamp bolt
The clamp bolt is responsible for reliably fastening two and a half clamps and is an important component of the clamp assembly. When the mud pump is in operation, the connection parts are subjected to continuous alternating loads and vibrations. Therefore, it is necessary to check whether the bolts, threads and related fastening structures are loose, stretched, worn or damaged.
The specifications, strength requirements and tightening methods of the clamp bolts used in different mud pumps may vary. Ordinary bolts cannot be used for replacement based on similar appearances. The specific fastening requirements should be carried out in accordance with the corresponding mud pump maintenance manual.
Common Failures and Inspections
After the clamp assembly has been subjected to reciprocating alternating loads for a long time, it is necessary to focus on inspecting the wear of the inner groove, abnormal mating surfaces, wear of the bolt holes, loosening or damage of the clamp bolts, and cracks in the main body, etc.
If abnormal sounds, loosening or vibration occur at the connection position, it is necessary to check whether the two half clamps are correctly paired, whether the inner groove is in contact with the end of the rod, whether the ends of the piston rod and the middle pull rod are worn, and whether the clamping fastener is in a normal state.
For clamps with cracks, obvious deformation or severe wear of the inner groove, it is not advisable to continue using them simply by increasing the bolt tightening force.
Key points for selection
When purchasing the drilling mud pump clamp assembly, it is recommended to focus on confirming the following information:
1. Brand, series and specific model of mud pump;
2. Original part number of the clamp assembly;
3. Model of the matching piston rod and the size of the rod end;
4. Model of the matching crosshead extension rod or middle pull rod;
5. Diameter of the inner groove of the clamp and the formed profile;
6. Inner groove width, depth and positioning structure;
7. The external dimensions and total width of the clamp;
8. Quantity, hole diameter and hole spacing of clamp bolts;
9. Specifications of matching bolts and fasteners;
10. Two-half clamp pairing identification;
11. Physical samples of original accessories or technical drawings.
Installation and Maintenance
Before installation, the inner grooves, mating surfaces of the two half clamps, as well as the connection ends of the piston rod and the middle tie rod should be cleaned. Mud, rust, oil stains and metal particles should be removed.
When installing, it is necessary to confirm that the piston rod is correctly connected to the end of the middle tie rod. The two halves of the clamp should be installed according to the original matching relationship. After the inner groove is correctly fitted to the positioning structure at the ends of both sides of the rod, it should be tightened.
The clamp bolts should be evenly tightened in accordance with the methods specified in the corresponding mud pump maintenance data. It is not advisable to compensate for the wear of the inner groove or abnormal rod end dimensions by arbitrarily increasing the tightening force.
After the mud pump has been in operation for a period of time, the condition of the clamps and fasteners should be checked in accordance with the equipment maintenance requirements. Before disassembly and assembly, the pump must be stopped and safety measures taken to prevent accidental rotation or movement of the power end.
Procurement Instructions
Juli Petroleum Drilling and Production Equipment Co., Ltd. provides clamp assemblies and piston transmission connection accessories for drilling mud pumps. The clamp assembly is mainly used to connect the piston rod with the crosshead extension rod or the intermediate tie rod. Different models of mud pumps vary in the inner groove structure, external dimensions, bolt specifications and the fit dimensions at the rod ends. When making a purchase, it is recommended to provide the model of the mud pump, the original part number of the clamp, the model of the piston rod and the intermediate tie rod, as well as the physical dimensions or technical drawings for matching verification.