Thermal Flow Meter

摘要

In order to provide a thermal flow meter capable of preventing adherence of contaminants to an air flow sensing portion, the thermal flow meter (300) of the invention includes a bypass passage for flowing a measurement target gas (30) received from a main passage (124) and an air flow sensing portion (602) for measuring a flow rate of the measurement target gas (30) by performing heat transfer with the measurement target gas (30) flowing through the bypass passage through a heat transfer surface (437). The air flow sensing portion (602) is provided to be exposed to an exposed surface (402) arranged along a flow direction of the measurement target gas (30) inside the bypass passage is embedded, the mount support surface (402) has a stage (407) formed to surround a periphery of the air flow sensing portion (602), and an inner portion surrounded by the stage protrudes more than an outer portion of the stage.

主权项

1. A thermal flow meter having a bypass passage for flowing a measurement target gas received from a main passage and an air flow sensing portion for measuring a flow rate of the measurement target gas by performing heat transfer with the measurement target gas flowing through the bypass passage through a heat transfer surface,
wherein the air flow sensing portion is provided to be exposed to a mount support surface arranged along a flow direction of the measurement target gas inside the bypass passage to embed the air flow sensing portion, the mount support surface has a stage formed to surround a periphery of the air flow sensing portion, and an inner portion surrounded by the stage protrudes more than an outer portion of the stage.