Thermal flow-rate sensor and method for determining the flow rate of a fluid
AssigneeFafnir GmbH
InventorWolfgang Schrittenlacher
Life of this patent
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Abstract
A thermal flow-rate sensor has a flow sensor (3) and a thermal-conductivity measuring cell (4). The flow sensor (3) comprises a first heating device and a first temperature detector, which reacts to the temperature of the first heating device, and can be exposed to a flowing fluid whose flow rate is to be determined. The thermal-conductivity measuring cell (4) comprises a measuring-cell casing (42), a second heating device and a second temperature detector which reacts to the temperature of the second heating device. The measuring-cell casing (42) has at least one opening (46) arranged for entry of the fluid into the measuring-cell casing (42).
Claims20
Thermal flow-rate sensor,
- with a flow sensor (3) which comprises a first heating device (32) and a first temperature detector (34), reacting to the temperature of the first heating device (32), and which can be exposed to a flowing fluid whose flow rate is to be determined, and
- with a thermal-conductivity measuring cell (4) which comprises a measuring-cell casing (42), a second heating device and a second temperature detector, reacting to the temperature of the second heating device, the measuring-cell casing (42) having at least one opening (46) arranged for entry of the fluid into the measuring-cell casing (42).
Method for determining the flow rate of a fluid,
- in which the fluid flows past a flow sensor (3) which comprises a first heating device (32) and a first temperature detector (34) which reacts to the temperature of the first heating device (32),
- in which a portion of the fluid enters a thermal-conductivity measuring cell (4) which comprises a measuring-cell-casing (42), a second heating device and a second temperature detector which reacts to the temperature of the second heating device, the measuring-cell casing (42) having at least one opening (46) arranged for entry of the fluid into the measuring-cell casing (42), and
- in which a first measuring signal, characterizing the heat dissipation capacity of the fluid, is generated by means of the heating power supplied to the second heating device and the temperature of the second temperature detector, and a second measuring signal, characterizing the flow rate of the fluid, is generated by means of the heating power supplied to the first heating device (32), the temperature of the first temperature detector (34) and the first measuring signal.
Dependencies are inferred from the claim text.