Installation, Usage, and Working Principle of Plum Blossom Couplings
Plum blossom couplings are commonly used inindustrial settings due to their simple structure, compact radial size, no needfor lubrication, high load-bearing capacity, and the requirement of half-couplings for axial movement. They also provide a certain degree ofcompensation for relative misalignment between two shafts.
Below is a brief introduction to the workingprinciple of plum blossom couplings.
Installation Instructions
Pre-Installation Inspection
Check whether the drive shaft (prime mover) and driven shaft (working machine) are concentric.
Inspect the shaft surfaces for packaging residue or damage.
Ensure the inner bores of both half-couplings are free of debris and that the edges are undamaged. If there are any burrs or scratches, clean the shafts and half-couplings, and smooth out imperfections with a fine file.
Verify that the inner bore diameter and length of both half couplings match the shaft diameter and extension length of the prime mover and working machine.
During selection, it is recommended that the half-coupling length be 10–30 mm shorter than the shaft extension length.
Heating for Easier Installation (Optional)
To facilitate installation, preheat the two half-couplings in a 120–150°C heating chamber or oil bath to expand the inner bore for easier fitting.
After installation, ensure the shaft end does not protrude beyond the coupling face—flush alignment is ideal.
Checking the Distance Between Half-Couplings
Measure the distance between the two half-couplings at 3–4 points along the inner flange edges and take the average.
Compare this with the sum of the spacer length and the actual measured thickness of the two diaphragm groups.
The error should be controlled within 0–0.4 mm.
Alignment
Bolt Installation
Insert bolts from the small holes on the outside of one flange and pass them through the large holes on the opposite flange.
Install buffer sleeves, elastic washers, and nuts, then tighten with a wrench.
Ensure smooth rotation after installation—no binding or excessive force should be required.
If disassembly or replacement is needed, avoid damaging the shafts or half-couplings.
Operator Guidelines
Before starting the equipment, check whether the coupling nuts are loose or missing. Tighten them with a wrench if necessary.
Startup Procedure: Run the equipment without load for 1 minute before opening the load pipeline valve.
Shutdown Procedure: Reverse the startup sequence.
Maintenance: Apply a coat of machine oil to the coupling exterior monthly to prevent rust.
Service Life & Precautions
If installed, maintained, and operated correctly (including proper alignment and bolt tightening), plum blossom couplings can withstand 15 starts per day and last over 5 years.
Common Causes of Premature Failure:
Incorrect bolt installation (causing deformation).
Excessive misalignment between the prime mover and working machine shafts.
Failure to follow installation and maintenance guidelines.
By adhering to these instructions, thecoupling’s performance and lifespan can be significantly extended.
August.zeng