Direct-heated flow measuring apparatus having improved sensitivity and response speed

Claim 2

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, said sensing portion being positioned on a downstream side of a connection portion between said sensing element and said supporting member with respect to said fluid stream within said passage, and said sensing element is approximately L-shaped having a first portion fixed to said supporting member and a second portion positioned on a downstream side with respect to said fluid stream, said portion being formed on said second portion.

Claim 3

An apparatus as set forth in claim 1, wherein an intersectron portion on said sensing element between said first and second portions is sloped with respect to said fluid stream.

Claim 4

An apparatus as set forth in claim 2, wherein the angle between said intersection portion and said fluid stream is substantially 45°.

Claim 5

An apparatus as set forth in claim 1, wherein said sensing element further comprises a third portion opposed to said second portion and protruded toward the upstream side with respect to said fluid stream.

Claim 6

An apparatus as set forth in claim 4, wherein said third portion has the same width as said second portion.

Claim 7

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which is rectangular and sloped with respect to said fluid stream, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, said sensing portion being positioned on a downstream side of a connection portion between said sensing element and said supporting member with respect to a fluid stream within said passage.

Claim 8

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which is rectangular and sloped with respect to said fluid stream, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, said sensing portion being positioned on a downstream side of a connection portion between said sensing element and said supporting member with respect to a fluid stream within said passage.

Claim 9

An apparatus as set forth in claim 6, wherein an angle between said sensing element and said fluid stream is substantially 10° to 60°.

Claim 10

An apparatus as set forth in claim 7, wherein said angle is substantially 20° to 40°.

Claim 11

An apparatus as set forth in claim 6, wherein said sensing element comprises: a substrate; a resistance layer formed on said substrate; and a passivation layer, formed on said substrate, for covering said resistance layer.

Claim 12

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element, comprising: (a) a semiconductor substrate; (b) a diffusion region formed within said semiconductor substrate; and (c) a passivation layer, formed on said semiconductor substrate, for covering said semiconductor substrate, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting a temperature thereof; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, said sensing portion being positioned on the downstream side of a connection portion between said sensing element and said supporting member with respect to a fluid stream within said passage.

Claim 13

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element, comprising: (a) a semiconductor substrate; (b) a diffusion region formed within said semiconductor substrate; and (c) a passivation layer, formed on said semiconductor substrate, for covering said semiconductor substrate, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting a temperature thereof; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, said sensing portion being positioned on the downstream side of a connection portion between said sensing element and said supporting member with respect to a fluid stream within said passage.

Claim 14

A direct-heated flow measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, wherein said sensing element is approximately L-shaped having a first portion fixed to said supporting member and a second portion positioned on the downstream side with respect to said fluid stream, said portion being formed on said second portion.

Claim 15

A direct-heated flow measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom, wherein said sensing element is approximately L-shaped having a first portion fixed to said supporting member and a second portion positioned on the downstream side with respect to said fluid stream, said portion being formed on said second portion.

Claim 16

An apparatus as set forth in claim 11, wherein an intersection portion on said sensing element between said first and second portions is sloped with respect to said fluid stream.

Claim 17

An apparatus as set forth in claim 12, wherein the angle between said intersection portion and said fluid stream is substantially 45°.

Claim 18

An apparatus as set forth in claim 11, wherein said sensing element further comprises a third portion opposed to said second portion and protruded toward the upstream side with respect to said fluid flow.

Claim 19

An apparatus as set forth in claim 14, wherein said third portion has the same width as said second portion.

Claim 20

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which is rectangular and sloped with respect to said fluid stream, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing e1ement in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom.

Claim 21

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which is rectangular and sloped with respect to said fluid stream, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing e1ement in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom.

Claim 22

An apparatus as set forth in claim 16, wherein an angle between said sensing element and said fluid stream is substantially 10° to 60°.

Claim 23

An apparatus as set forth in claim 17, wherein said angle is substantially 20° to 40°.

Claim 24

An apparatus as set forth in claim 16, wherein said sensing element comprises: a substrate; a resistance layer formed on said substrate; and a passivation layer, formed on said substrate, for covering said resistance layer.

Claim 25

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which comprises: a semiconductor substrate; a diffusion region formed within said semiconductor substrate; and a passivation layer, formed on said semiconductor substrate, for covering said semiconductor substrate, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom.

Claim 26

A direct-heated flow measuring apparatus for measuring a flow rate of a fluid stream within a passage comprising: a thin-plate sensing element which comprises: a semiconductor substrate; a diffusion region formed within said semiconductor substrate; and a passivation layer, formed on said semiconductor substrate, for covering said semiconductor substrate, said sensing element being disposed in parallel with said fluid stream within said passage and having a sensing portion for generating heat and detecting the temperature thereof, said sensing portion being positioned on a most downstream-side portion of said sensing element with respect to the fluid stream within said passage; a supporting member for supporting said sensing element in said passage at at least one end of said sensing element; and electric power control means, connected to said sensing portion of said sensing element, for controlling the heat generated therefrom.