Diaphragm coupling is used to connect motor and fan after removing liquid coupling. The double diaphragm coupling shaft has long distance connection and large torque, and can also modify the concentricity deviation between the motor and the fan to a certain extent, so as to realize simple and stable rotation. It is an ideal connecting equipment with long interval and large torque, especially suitable for the connection between the motor and the fan after the liquid coupling is removed. It is very convenient to install, in a working day can complete the removal of the liquid coupling and the installation of coupling, will not have a great impact on production. In the practical application of energy saving transformation, compared with the hydraulic coupler speed regulation, frequency conversion speed regulation is a kind of speed regulation mode with upper wind. The advantages of frequency converter speed regulation are high speed regulation efficiency, low start energy consumption, wide range of speed regulation, stepless speed regulation, fast dynamic response, high speed precision, simple operation, and easy to realize automation of production process control. So many high-voltage frequency conversion transformation at present is based on the original equipment with hydraulic coupler. Since the equipment used hydraulic coupler, high-pressure frequency conversion control is used. Considering the stability of fan operation, two methods are generally adopted for the transformation:

Coupling is an important part of mechanical transmission system, which is often used to connect two shafts or shafts with rotating parts to transmit torque and movement. It is widely used in metallurgy, chemical industry, machinery, vehicle, ship, electronics, aircraft and other industrial parts. The coupling is generally divided into flexible coupling with metal elastic elements, which has the following main characteristics:

1. The elastic element has higher strength, smaller volume and compact structure than other coupling which transmit the same torque.
2. Stable performance and long service life
3. Manufacturing is more complex and cost is higher

The metal elastic elements are mostly diaphragm, bellows, connecting rod, etc. Metal elastic element coupling is widely used in:

1. Pumps and fans with high power and high speed
2. Crushing machine with large impact torque and severe load change
3. Precision transmission machinery, data transmission system.
4. High temperature, high precision transmission requirements.
5. The gap between the two coupling is too wide, which causes the diaphragm to be subjected to greater axial force, and the twisted holes or the twisted bolts are worn, causing abnormal noise;
6. The axial offset or deflection angle of the coupling are too large, which will also cause vibration and abnormal noise when the equipment is running;
7. When the speed of active end and passive end is different, vibration and abnormal sound will be produced when the equipment is running;
8. The speed code plate of the motor fails, which causes the speed of the motor to be fast and slow, and makes the diaphragm coupling make abnormal noise.