Thermal flow rate measuring device
AssigneeHitachi, Ltd.
InventorsIzumi Watanabe, Junichi Horie, Keiichi Nakada, Kei Ueyama
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Abstract
A thermal type flow rate measuring device can certainly prevent adhesion of water droplet onto a sensor element and thus achieve high reliability. The thermal type flow rate measuring device includes an auxiliary passage defined within a main passage for introducing a part of fluid flowing through the main passage, a sensor disposed within the auxiliary passage for detecting flow rate of the fluid and capturing means formed on an inner periphery of the auxiliary passage for capturing liquid contained in the fluid and transferring the captured liquid.
Claims12
A thermal type flow rate measuring device comprising:
- an auxiliary passage defined within a main passage for introducing a part of fluid flowing through said main passage;
- a sensor disposed within said auxiliary passage for detecting flow rate of the fluid;
- and
- capturing means formed on an inner periphery of said auxiliary passage for capturing liquid contained in said fluid and transferring the captured liquid.
3, A thermal type flow rate measuring device as set forth in claim 2, wherein said capturing means or said capturing means and said discharge means is formed with one of a plurality of grooves, a plurality of beam-like ridges and a combination of a plurality of grooves and a plurality of beam-like ridges, said captured liquid is transferred along said one of a plurality of grooves, a plurality of beam-like ridges and a combination of a plurality of grooves and a plurality of beam-like ridges,
A thermal type flow rate measuring device as set forth in claim 3, wherein a plurality of grooves, a plurality of beam-like ridges and a combination of a plurality of grooves and a plurality of beam-like ridges extends from upstream side to downstream side in said auxiliary passage in a manner directed from portions on the inner periphery of said auxiliary passage where liquid passing through said auxiliary passage is hardly concentrated to portions on the inner periphery of said auxiliary passage where liquid passing through said auxiliary passage is easily concentrated.
A thermal type flow rate measuring device as set forth in claim 3, wherein a plurality of grooves, a plurality of beam-like ridges and a combination of a plurality of grooves and a plurality of beam-like ridges extends from upstream side to downstream side in said auxiliary passage in a manner directed from portions of the inner periphery of said auxiliary passage where centrifugal to be applied is small to portions of the inner periphery of said auxiliary passage where centrifugal force to be applied is large.
A thermal type flow rate measuring device as set forth in claim 3, wherein a plurality of grooves, a plurality of beam-like ridges and a combination of a plurality of grooves and a plurality of beam-like ridges extend oblique relative to flow direction of the fluid.
A thermal type flow rate measuring device comprising:
- a sensor provided within a main passage through which a fluid flows, for measuring flow rate of said fluid in said main passage;
- said main passage being curved in the vicinity of an upstream side of said sensor;
- and
- capturing means formed on an inner periphery of said main passage for capturing a liquid carried by said fluid.
A thermal type flow rate measuring device in a vehicle control system including a thermal type flow rate control device, a control unit for controlling a vehicle on the basis of the condition of vehicle detected by said thermal type flow rate measuring sensor, said thermal type flow rate measuring device including an auxiliary passage introducing a part of fluid flowing through a main passage, and a sensor for detecting flow rate of the fluid, for detecting flow rate of the liquid,
- a liquid capturing means and/or discharging means being provided on an inner periphery of said auxiliary passage.
Dependencies are inferred from the claim text.