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Fluid Drives and Fluid Couplings

Fluid drives and fluid couplings are hydrodynamic devices that transmits rotational power. There are 4 main components of a fluid coupling: The housing, the input element (including the impeller), the output element (including the runner) and the oil. The housing contains the oil and the rotating mechanical components. The input element connects to the driving equipment like a motor or a turbine. Inside the coupling or fluid drive is an impeller. The impeller drives. The output element connects to the driven equipment such as a pump or fan. Inside the coupling is a runner. Between the input and output elements is oil. Kinetic energy is added to the oil when input element rotates. This energy is smoothly transferred to the output element and the driven equipment.

TRI fluid couplings are used for soft starts, vibration isolation and equipment protection. They are run with full oil or with just cooling oil.

TRI fluid drives are similar to fluid couplings with the added variable speed functions. The output speed of a fluid drive can be reduced by removing some of the oil form the inside of the coupling. This creates a slip condition causing the output shaft to slow down. A typical application for the fluid drive is to control the speed of a pump or compressor.


More Information:

Chose a fluid drive/fluid coupling catalog to download:

Variable Speed Fluid Drives (270 KB)

Fluid Drives for Diesel Engines (741 KB) 

General Purpose Fluid Drives (554 KB)

Chose a Tech Note to download:

Tech Note Febuary 2015: Improving a Critical Component of a Fluid Drive: The Scoop Tube

Tech Note June 2003: Solutions for over-heating and vibration: two common problems of existing fluid drives.

Chose a Case Study to download:

Case Study: Vibration Patterns Expected for Variable Speed Fluid Drives

Case Study: Fluid Drive for ID Fan

Case Study: Fluid Drive for Large Compressors and Pumps