Turbine flowmeters

Turbine flowmeter principle

A turbine flow meter has a turbine that is placed axially. When the medium flows faster through the meter, the turbine rotates faster. The revolutions are counted, usually with a magnetometer. With this principle the flow can be calculated.

Bearings of turbine flowmeters

Because gases and liquids are not all the same, there are different types of turbine flowmeters. The main differences are found in the shape of the turbine and the bearing, which is the weak point of turbine meters. They can break down, parts can be sensitive to aggressive media and in applications where cleanliness is required, bearing lubrication can cause contamination. For all these problems, various solutions have been found by manufacturers. The high-end instruments can be fitted with a cartridge. This is more expensive, but has a number of important advantages:

• It is possible to ship the cartridge with the sensitive parts separately from the body.
• The exchange of the cartridge. This makes it possible to change the measuring range, or to replace the cartridge by a new or recalibrated cartridge; thus saving costs.
• The body can be made of another material.
• The body is pressure holding, not the "loose" cartridge. This makes it easier to handle higher process pressures.