• Font Size
  • Normal
  • Large

CHAPTER 2FLOW METER TYPES & PRINCIPLES
THERMAL FLOW METER

PRINCIPLES

When fluid comes into contact with a heated object, the fluid takes heat away from the object, increasing the temperature of the fluid. A thermal flow meter uses this principle to measure flow. Thermal flow meters can be divided into two groups:

THERMAL FLOW METER

THERMAL FLOW METER

(1) The temperature difference measurement method

A heater is installed in the fluid, and fluid temperature is measured at 2 points, upstream and downstream. Then flow is determined by the temperature difference between these 2 points. This is primarily used for applications with low flow rates.

(2) The power consumption measurement method

A heater is installed in the fluid and fluid temperature is measured at 2 points, upstream and downstream. The heater is controlled to constantly maintain a fixed temperature difference between these 2 points. Flow is determined based on the amount of power required to maintain this temperature.

FEATURES OF A THERMAL FLOW METER

PROS ・Able to detect gases
・There is basically no pressure loss
・Can measure mass flow
CONS ・Errors occur when the temperature of the fluid changes
・It is difficult to set-up specifications that match the type and composition of the fluid.
・Errors occur when there are deposits/buildup on the temperature sensors or heating element.

Back to INDEX

Back to page top

To solve the problem related to the Flow Sensor!