Fluid Coupling

Definition:

Fluid coupling is a hydrodynamic device which is?used to transfer rotational power from one shaft to another?by the use of transmission fluid.

Types:

There are two types of fluid coupling normally.

1. Constant Filling: Where the oil filling is fixed.
2. Variable Filling: Where the quantity of oil in the working circuit can be varied whilst running to give control over the amount of slip between the impeller and runner and so give speed regulation. (Will Discuss later)

Uses:

Used in automotive transmission system, marine propulsion system and in industries for power transmission.

In Industries: Fluid couplings are used in?Belt Conveyors, Extruders, Centrifuges, Bucket elevators, Ball mills, Crushers, Mixers, Slurry pumps, Compressors, Industrial fans, Feeders, Diesel locomotives, Wagon tipplers, Boiler feed pumps, Reciprocating pumps, Process Pumps, Dryers etc.

Components:

Fluid Coupling consist of following Parts,

• Input Shaft
• Pump Wheel (Driver Wheel)
• Turbine Wheel (Driven Wheel)
• Output Shaft
• Casing
• Fusible Plug (Safety component capable of protecting the motor and the machine from over torque by leaking the fluid from coupling)

Working Principle:

A fluid coupling consists of an input shaft which is connected to the external driving shaft, with the help of this driving shaft the input shaft of the coupling gets rotated and generates kinetic energy this energy gets transferred to the fluid present it. the fluid used to convert into the centrifugal force and apply on the turbine to rotate it, with the help of centrifugal force the turbine gets rotated which is at the same torque produced by the input shaft called an impeller. This rotational power generated by the turbine gets transferred by connecting an output shaft to the turbine shaft.

Advantages of Fluid Coupling:

• No Wear.
• High torque transmission is possible.
• Easy to use and install.
• Less complex in design and maintenance.
• High efficiency as compared to others.
• A smooth function is obtained.

Disadvantages of Fluid Coupling:

• Cannot use at higher temperatures.
• Maintenance is more.
• Adequate ventilation is required in predicted areas.
• leakages should check properly.
• Slippage is more.