Flow Measurement

# What is a turbine flow meter and how is it constructed

#### What is a turbine flow meter

Turbine flow meters are used in many industrial applications to measure the flow of liquid and gas. It consists of a multi-blade rotor mounted with a pipe perpendicular to the fluid flow. When the liquid passes through the blades, the rotor will spin. The speed of the rotor is depended upon the flow rate, so it can be measured by using a photoelectric cell or gears. This flow meter would convert the mechanical action of the turbine as the fluid flow rate. This device would rotate according to the flow in which it is placed, the number of revolution is proportional to the flow.

#### How turbine flow meter is constructed

The major part of this device is a multi-blade rotor and this rotor is mounted at an angle that the fluid flow can rotate the rotor. A ball bearing supports the rotor on a shaft which is retained in the flow meter housing by shaft support section. A magnetic pick up is mounted to the turbine wheel, and the sensor would record the voltage pulse that is created. Then the voltage information is then translated into actual flow meter reading.

#### What is the principle of turbine flow meter and how does it work

The turbine is rotated by the flowing fluid, these rotating blades would create pulses that would be recorded and the flow rate is determined by this. The pulse rate is depended upon the flow rate. This device would convert the mechanical action of the rotating turbine in the liquid flow around an axis into a user-readable rate of flow. The blades on the rotor is placed in a way that, can transform the energy of the flow into rotational energy. The rotor shaft spins on the bearings when the fluid moves faster then the rotor would spin faster too. These flow meters are used to measure the velocity of fluids and gases in pipes. Shaft rotation is sensed mechanically or by the blade movements. The movement of the blade is also detected magnetically. More pulse would be generated when the fluid flows faster and this flow could be measured, the transmitter would process the pulse signal to determine the flow rate. These meters can be used when accuracy, compact size, and fast response is required.

#### What are the advantages of a turbine flow meter

• Good accuracy
• Low-pressure drop
• Easy to install
• Good temperature and pressure rating
• Excellent repeatability and range
• The construction materials would allow to use it with many process fluid
• Simple and durable
• It can be easily connected to the electronic readout device for flow control and computer interface

#### What are the disadvantages of turbine flow meter

• High cost
• Limited use for slurry applications
• Problems caused by non-lubricating fluids
• Less accurate at low flow rates
• It cannot be operated at high velocity
• Moving parts
• Sensitive to flow profile
• Interchangeability from unit to unit is very poor
• The bearing is depended on the cleanliness and lubricity of the process fluid
• Wear and tear could happen to the turbine blades and it needs to be calibrated frequently
• For certain liquid applications, there could be problems such as cavitation, specific gravity, and viscosity

#### What are the applications of turbine flow meter

• Military applications
• It is used in the blending system of the petroleum industry
• Airborne applications for energy fuel and cryogenic flow measurement
• Chemical industries
• Food and beverage
• Oil and gas
• Refining
• Semiconductor
• Agricultural
• Pharmaceutical
• Photo development
• Process control
• Food beverage dispensing