Oscillating Piston Flow Meter Working, Applications, Advantages and Disadvantages
Oscillating piston flow meter construction and working
It is one of the oldest type positive displacement flow meters. The oscillating piston meter is similar to nutating disc meter, except that the measurement devices Is a split ring/ piston which oscillated in one plane only. It consists a precision machined chamber (slotted cylinder that separate inlet and outlet part), a cylindrical piston. The movement of central piston constrained to run in a circular groove; it has an eccentric motion about center chamber axis. Center piston rotate as the liquid subsequently enters and exit from the chamber. Normally hydraulically floating piston do not come into contact with chamber.The housing normally made of brass or bronze, in some case plastic also used. A strainer of suitable mesh size is provided at the inlet, which avoids the entering of suspended solid particle into the chamber.
The liquid enters and exit through the opening on flow meter chamber, underside to the piston. The pressure of fluid rotates the center hub. This rotation transmitted to register either by mechanically or magnetically through the diaphragm. Each revolution of piston indicates the corresponding movement of fixed amount of liquid.
Applications of oscillating piston flow meter
Oscillating piston meter suited for viscous fluid (paint, resin, ink). They are used oil metering where turn down is not critical. They can be used in the automatic liquid batching system. They are ideal for food and beverage application (honey, chocolate).Read: Advantages and disadvantages of positive displacement flow meters
Advantages and disadvantages of oscillating piston flow meter
Advantages- It can be easily used in automatic liquids batching system
- Simple construction. Easy to install and maintenance
- Replacement of internal parts can be done without disconnecting meter from the pipeline.
- Good accuracy especially at low flow rate
- Eliminate straight pipeline in upstream and downstream.
- It can be used in any direction (horizontal, vertical, or inclined)
- It can be connected to mechanical as well as electronic registers.
- Moderate cost
Disadvantages
- Available only in small sizes
- Only used in relatively clean fluids
- Moving parts subjected to wear
