Basic Knowledge of Diaphragm Couplings – Extremely Useful for Air Compressors, Let’s Learn!
A coupling is a mechanical component that connects two shafts (driving shaft and driven shaft) of different mechanisms to rotate jointly and transmit torque. In high-speed and heavy-load power transmission, some couplings can buffer vibration, damp shocks and improve the dynamic performance of the shaft system. On air compressors, couplings are adopted to connect the main rotor and the electric motor.
Today we will focus on introducing diaphragm couplings. The diaphragm coupling is a type of flexible coupling equipped with elastic elements. Separate elaboration on this coupling fully demonstrates its significance.
01 Structural Composition of Diaphragm Couplings
The diaphragm coupling is a metal flexible coupling. It serves as a transmission device that transfers torque by taking metal elastic diaphragms as flexible components.
Main characteristics: High torque transmission capacity; misalignment of the unit is accommodated through diaphragm deformation; no relative movement between components, hence zero wear and noise; excellent vibration damping performance and long service life; lubrication-free. Torsional stiffness and critical speed can be adjusted by changing the outer diameter or wall thickness of the spacer, so as to optimize the torsional vibration characteristics of the unit.
A diaphragm coupling consists of at least one diaphragm and two hubs. The diaphragm is fastened to the hubs by pins, which generally prevents loosening or backlash between the diaphragm and hubs. Some manufacturers supply couplings with two or three diaphragms, equipped with one or two rigid intermediate components connected to hubs on both sides.
The difference between single-diaphragm couplings and double-diaphragm couplings lies in their capacity to compensate for various deviations. The single-diaphragm coupling requires complex bending of the diaphragm, so it cannot accommodate eccentricity well. In contrast, the double-diaphragm coupling allows diaphragms to bend in different directions simultaneously to compensate for eccentricity.
02 Main Properties of Diaphragm Couplings
(1) Powerful capacity to compensate for misalignment of two shaft axes. It can withstand twice the angular displacement compared with gear couplings, generates low reaction force under radial displacement and features great flexibility. A certain amount of axial, radial and angular displacement is permitted.
(2) Remarkable vibration damping effect, free of noise and wear.
(3) Capable of operating under high temperature (-80°C ~ +300°C) and harsh environments, and can run safely under impact and vibration conditions.
(4) High transmission efficiency up to 99.86%, especially suitable for medium & high-speed high-power transmission.
(5) Simple structure, light weight, compact size and convenient assembly & disassembly. The spacer type can be mounted and disassembled without moving the equipment, and no lubrication is required.
(6) Rotational speed can be transmitted accurately without speed slip, applicable to transmission of precision machinery.
Currently available diaphragm couplings can be manufactured for a maximum transmission power of 50,000 kW, maximum rotational speed of 80,000 rpm, and maximum spacer length of 12 meters. Multiple modification schemes are available for diaphragm couplings.
03 Applications of Diaphragm Couplings
Diaphragm couplings are widely applied in shaft transmission of various mechanical equipment, including water pumps (especially high-power chemical pumps), fans, compressors, hydraulic machinery, petroleum machinery, printing machinery, textile machinery, chemical machinery, mining machinery, metallurgical machinery, aviation (helicopters), high-speed power transmission systems for ships, steam turbines, transmission systems of reciprocating power machinery, tracked vehicles, as well as high-speed high-power transmission systems of generator sets. Balanced diaphragm couplings are commonly used in high-speed transmission shaft systems.
04 Causes of Abnormal Noise in Diaphragm Couplings
(1) Excessively large gap between the two coupling halves subjects the diaphragm to heavy axial force, leading to wear of reamed holes or reamer bolts and generating abnormal noise.
(2) Excessive axial offset or deflection angle between the two coupling halves triggers vibration and abnormal noise during equipment operation.
(3) Speed difference between driving side and driven side causes vibration and abnormal noise during operation.
(4) Fault of the motor speed encoder leads to fluctuating motor speed, resulting in abnormal noise of the diaphragm coupling.
Today we will focus on introducing diaphragm couplings. The diaphragm coupling is a type of flexible coupling equipped with elastic elements. Separate elaboration on this coupling fully demonstrates its significance.
01 Structural Composition of Diaphragm Couplings
The diaphragm coupling is a metal flexible coupling. It serves as a transmission device that transfers torque by taking metal elastic diaphragms as flexible components.
Main characteristics: High torque transmission capacity; misalignment of the unit is accommodated through diaphragm deformation; no relative movement between components, hence zero wear and noise; excellent vibration damping performance and long service life; lubrication-free. Torsional stiffness and critical speed can be adjusted by changing the outer diameter or wall thickness of the spacer, so as to optimize the torsional vibration characteristics of the unit.
A diaphragm coupling consists of at least one diaphragm and two hubs. The diaphragm is fastened to the hubs by pins, which generally prevents loosening or backlash between the diaphragm and hubs. Some manufacturers supply couplings with two or three diaphragms, equipped with one or two rigid intermediate components connected to hubs on both sides.
The difference between single-diaphragm couplings and double-diaphragm couplings lies in their capacity to compensate for various deviations. The single-diaphragm coupling requires complex bending of the diaphragm, so it cannot accommodate eccentricity well. In contrast, the double-diaphragm coupling allows diaphragms to bend in different directions simultaneously to compensate for eccentricity.
02 Main Properties of Diaphragm Couplings
(1) Powerful capacity to compensate for misalignment of two shaft axes. It can withstand twice the angular displacement compared with gear couplings, generates low reaction force under radial displacement and features great flexibility. A certain amount of axial, radial and angular displacement is permitted.
(2) Remarkable vibration damping effect, free of noise and wear.
(3) Capable of operating under high temperature (-80°C ~ +300°C) and harsh environments, and can run safely under impact and vibration conditions.
(4) High transmission efficiency up to 99.86%, especially suitable for medium & high-speed high-power transmission.
(5) Simple structure, light weight, compact size and convenient assembly & disassembly. The spacer type can be mounted and disassembled without moving the equipment, and no lubrication is required.
(6) Rotational speed can be transmitted accurately without speed slip, applicable to transmission of precision machinery.
Currently available diaphragm couplings can be manufactured for a maximum transmission power of 50,000 kW, maximum rotational speed of 80,000 rpm, and maximum spacer length of 12 meters. Multiple modification schemes are available for diaphragm couplings.
03 Applications of Diaphragm Couplings
Diaphragm couplings are widely applied in shaft transmission of various mechanical equipment, including water pumps (especially high-power chemical pumps), fans, compressors, hydraulic machinery, petroleum machinery, printing machinery, textile machinery, chemical machinery, mining machinery, metallurgical machinery, aviation (helicopters), high-speed power transmission systems for ships, steam turbines, transmission systems of reciprocating power machinery, tracked vehicles, as well as high-speed high-power transmission systems of generator sets. Balanced diaphragm couplings are commonly used in high-speed transmission shaft systems.
04 Causes of Abnormal Noise in Diaphragm Couplings
(1) Excessively large gap between the two coupling halves subjects the diaphragm to heavy axial force, leading to wear of reamed holes or reamer bolts and generating abnormal noise.
(2) Excessive axial offset or deflection angle between the two coupling halves triggers vibration and abnormal noise during equipment operation.
(3) Speed difference between driving side and driven side causes vibration and abnormal noise during operation.
(4) Fault of the motor speed encoder leads to fluctuating motor speed, resulting in abnormal noise of the diaphragm coupling.
