Thermal Mass Flowmeter

Today's introduction is──Thermal Mass Flow Meter

 

Thermal Mass Flow Meter
When a fluid contacts a heated object, it removes heat from the object and the temperature of the fluid increases. Thermal mass flow meters use this principle to measure flow.

 

Thermal mass flow meters can be divided into two categories:

(1)Thermometry
A heater is installed in the fluid and the fluid temperature is measured at two points upstream and downstream. The flow rate is then derived from the temperature difference between these two points. This is mainly used when traffic is low.

(2)Power consumption measurement method
A heater is installed in the fluid and the fluid temperature is measured at two points upstream and downstream. The temperature difference between these two points is kept constant by controlling the heater. The flow rate is based on the power required to maintain this temperature.

 

Advantage:
・Able to detect gas
・Basically no pressure loss
・Can measure mass flow

 

Shortcoming:
・Error occurs when the temperature of the fluid changes
・Difficulty setting specifications to match fluid type and composition
・Errors can occur when there is sediment, fouling on the temperature sensor or heating element

 

source:KEYENCE

The application fields include the management of unit energy consumption for the purpose of energy saving in semiconductor thin film process plants, and it is mainly used to control the gas in the semiconductor process.

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