Patent EP0131318A1 successfully refreshed from Google Patents.
EP0131318A1
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Fluid flow measuring device
Assignee: Bronkhorst High-Tech BV
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Filing: 1984-05-17
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Granted: —
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Expires: 2004-05-17
Abstract
Abstract Fluid flow measuring device comprising sensor elements positioned onto the outer wall of the thermically conducting measuring channel and thermically insulated from the environment by an insulating body. The sensor elements can be heated for creating a temperature gradient as a function ofthe fluid flow rate, which temperature gradient can be converted into an electrical measuring signal using a bridge circuit. The bridge circuit comprises four sensor elements which two by two are connected in series and are positioned onto the fluid measuring channel such that of each series circuit one element is positioned onto a fluid measuring channel such that of each series circuit one element is positioned onto a first section of the fluid measuring channel upstream in relation to a second section of the fluid measuring channel onto which the other element of the respective series circuit is positioned, whereby the downstream end of each series circuit is connected to the upstream end of the respective other series circuit, and the electrical measuring signal is available at the junctions within said series circuits. The sensor elements are formed by thin or thick film resistors or integrated semiconductors onto the electrically insulating fluid measuring channel respectively onto a thin insulating layer onto the electrically conducting fluid measuring channel.
Inventors
- 👤 Wijbren Jouwsma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 03:06
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/6847; G01F1/688; G01F1/69; G01F1/692
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
102 words
Fluid flow measuring device for measuring the flow rate of a fluid flowing through a thermically conducting fluid measuring channel, comprising sensor elements positioned onto the outside wall of the measuring channel, which elements can be heated for creating a temperature gradient as function of the fluid flow rate, which temperature gradient can be converted into an electrical signal by means of a measuring circuit, characterized in that the sensor elements are in integrated form positioned onto a thin substrate of good heat conducting and electrically insulating material which substrate is attached to the outer wall of the fluid flow measuring channel.
Claim 2
Dependent Claim
102 words
Fluid flow measuring device for measuring the flow rate of a fluid flowing through a thermically conducting fluid measuring channel, comprising sensor elements positioned onto the outside wall of the measuring channel, which elements can be heated for creating a temperature gradient as function of the fluid flow rate, which temperature gradient can be converted into an electrical signal by means of a measuring circuit, characterized in that the sensor elements are in integrated form positioned onto a thin substrate of good heat conducting and electrically insulating material which substrate is attached to the outer wall of the fluid flow measuring channel.
Claim 3
Dependent Claim
29 words
Fluid flow measuring device according to claim 1, characterized in that the fluid flow measuring device comprises separate heater elements which also in integrated form are positioned ontosaid substrate.
Claim 4
Dependent Claim
29 words
Fluid flow measuring device according to claim 1 or 2, characterized in that at least part of the components of the measuring circuit are directly positioned onto the substrate.
Claim 5
Dependent Claim
23 words
Fluid flow measuring device according to one of the preceding claims, characterized in that the substrate is made of glass or aluminium oxide.
Claim 6
Dependent Claim
35 words
Fluid flow measuring device according to one of the preceding claims 1-4, characterized in that the sensor elements consist of int egrated semiconductors which in the form of a chip are positioned onto the substrate.
Claim 7
Dependent Claim
33 words
Fluid flow measuring device according to claim 5, comprising separate heater elements, characterized in that also said heater elements are as integrated semiconductors in the form of a chip positioned onto the substrate.
Claim 8
Dependent Claim
40 words
Fluid flow measuring device according to claim 5, characterized in that the semiconductors in the form of a chip are bonded to the fluid measuring channel whereby the bonding or adhesive layer together with the chip material forms said substrate.
Claim 9
Dependent Claim
38 words
Fluid flow measuring device according to claims 1-3, characterized in that the substrate consists of semiconductor material whereby the sensor elements and the heater elements and at least parts of the measuring circuit are integrated into the substrate.
Claim 10
Dependent Claim
27 words
Fluid flow measuring device according to one of the preceding claims, characterized in that the substrate forms part of the wall of the fluid flow measuring chanel.
Claim 11
Dependent Claim
27 words
Fluid flow measuring device according to one of the preceding claims, characterized in that the fluid flow measuring channel is at least partly formed into the substrate.
Claim 12
Dependent Claim
41 words
Fluid flow measuring device according to claim 10, characterized in that, in one side of the substrate a groove or excavation is formed which, after positioning a closing element to that side of the substrate, determines the fluid flow measuring channel.
Claim 13
Dependent Claim
24 words
Fluid flow measuring device according to claim 10, characterized in that the substrate comprises a through going passage functioning in as fluid measuring channel.
Claim 14
Dependent Claim
41 words
Fluid flow measuring device according to one of the claims 1-12, characterized in that an in general U-shaped element is positioned against the substrate such that the thereby created closed space within the U-shaped element determines the fluid flow measuring channel.
Claim 15
Dependent Claim
63 words
Method for fabricating a fluid flow measuring device according to one of the claims 1-8, characterized in that the sensor elements are applied onto a thin substrate of good heat conducting and electrically insulating material in the form of thin or thick film resistors of temperature sensitive material, whereafter the substrate will be bonded to the outer wall of the fluid measuring channel.
Claim 16
Dependent Claim
51 words
Method for fabricating a fluid flow measuring device according to claim 14, characterized in that the substrate is made of a foil material, onto which the sensor elements and, if present, also the heater elements are formed by means of etching a layer of resistance material present onto said foil material.
Claim 17
Dependent Claim
69 words
Method for fabricating a fluid flow measuring device according to one of the claims 1-8 inclusive, characterized in that the substrate is formed onto the outer wall of the fluid measuring channel in the form of a thin layer of electrically insulating and good heat conducting material, whereafter the sensor elements are applied onto said substrate in the form of thin or thick film resistors of temperature sensitive material.
Claim 18
Dependent Claim
41 words
Method according to claim 16 for fabricating a fluid flow measuring device comprising separate heater elements, characterized in that the heater elements are applied onto the substrate in the form of thin or thick film resistors just as the sensor elements.
Claim 19
Dependent Claim
28 words
Method according to claim 16 or 17, characterized in that the substrate is applied in the form of a thin enamel layer by means of an enameling process.
Claim 20
Dependent Claim
30 words
Method according to 16 or 17, characterized in that the substrate is applied is a thin layer by means of sputtering or vacuum deposition or deposition within a galvanic bath.
Claim 21
Dependent Claim
30 words
Method according to 16 or 17, characterized in that the substrate is applied is a thin layer by means of sputtering or vacuum deposition or deposition within a galvanic bath.
Claim 22
Dependent Claim
51 words
Method according to one of the claims 16-19 inclusive, characterized in that the material of the resistors is applied by means of vacuum deposition for sputtering or deposition into a galvanic bath, whereafter locally material is removed by means of etching or by laser cutting to obtain the desired resistor shape.
Claim 23
Dependent Claim
66 words
Method for fabricating a fluid flow measuring device according to one of the claims 1 - 8, characterized in that the fluid flow measuring channel is made of aluminium, onto which a layer of aluminium oxide is formed functioning as substrate onto which the sensor elements, heater elements and components of the measuring circuit are applied in the form of a thin or thick film circuit.
Claim 24
Dependent Claim
178 words
Fluid flow measuring device for measuring the flow rate of fluid flowing through a thermically conducting fluid measuring channel comprising sensor elements positioned onto the outer wall of the measuring channel and thermically insulated from the environment by an insulating body, which sensor elements can be heated for creating a temperature gradient as a function of the fluid flow rate, which temperature gradient can be converted into an electrical measuring signal using a bridge circuit, characterized in that said bridge circuit comprises four sensor elements which two by two are connected in series and are positioned onto the fluid measuring channel such that of each series circuit one element is positioned onto a first section of the fluid measuring channel upstream in relation to a second section of the fluid measuring channel onto which the other element of the respective series circuit is positioned, whereby the downstream end of each series circuit is connected to the upstream end of the respective other series circuit, and the electrical measuring signal is available at the junctions within said series circuits.
Claim 25
Dependent Claim
178 words
Fluid flow measuring device for measuring the flow rate of fluid flowing through a thermically conducting fluid measuring channel comprising sensor elements positioned onto the outer wall of the measuring channel and thermically insulated from the environment by an insulating body, which sensor elements can be heated for creating a temperature gradient as a function of the fluid flow rate, which temperature gradient can be converted into an electrical measuring signal using a bridge circuit, characterized in that said bridge circuit comprises four sensor elements which two by two are connected in series and are positioned onto the fluid measuring channel such that of each series circuit one element is positioned onto a first section of the fluid measuring channel upstream in relation to a second section of the fluid measuring channel onto which the other element of the respective series circuit is positioned, whereby the downstream end of each series circuit is connected to the upstream end of the respective other series circuit, and the electrical measuring signal is available at the junctions within said series circuits.
Claim 26
Dependent Claim
48 words
Fluid flow measuring device according to claim 22, characterized in that the sensor elements are formed by resistance elements which in the form of thin layers are realized onto the electrically insulating fluid measuring channel respectively onto a thin insulating layer onto the electrically conducting fluid measuring channel.
Claim 27
Dependent Claim
49 words
Fluid flow measuring device according to claim 22, characterized in that the sensor elements are formed by transistors which in integrated form are positioned onto a thin substrate of good heat conducting and electrically insulating material, which substrate is positioned onto the outer wall of the fluid measuring channel.
Claim 28
Dependent Claim
50 words
Fluid flow measuring device according to one of the claims 22-24, characterized in that the fluid flow measuring device comprises separate heater elements which also either in integrated form or in the form of a thin layer of material are positioned onto the outer wall of the fluid measuring channel.
Claim 29
Dependent Claim
48 words
Fluid flow measuring device according to one of the claims 22-25, characterized in that at least a part of the components of the measuring circuit is also positioned in integrated form or in the form of thin material layers onto the outer wall of the fluid measuring channel.
Claim 30
Dependent Claim
111 words
Fluid flow measuring device according to one of the claims 22-26, in which either the sensor elements, functioning also as heater elements, or the separate heater elements are embodied as resistance elements, through which resistance elements in the first instance a constant electrical current is supplied, characterized in that the resistance material of said resistance elements as well as the insulation value of the insulating body are selected such that the increase of heat released by said element with increasing resistance value of said elements caused by an increase of the own fluid temperature will be at least approximately compensated by the increase of the heat losses through said insulating body.
Claim 31
Dependent Claim
75 words
Method for fabricating a fluid flow measuring device according to one of the claims 22-27, characterized in that a thin layer of electrically insulating and good heat conducting material is deposited onto the outer wall of the fluid measuring channel, whereafter onto the substrate formed in this way the sensor elements in the form of thin or thick film resistors of temperature sensitive material are deposited whereafter the insulating body is formed around said elements.
Claim 32
Dependent Claim
38 words
Method according to claim 28 for fabricating a fluid flow measuring device with separate heater elements, characterized in that the heater elements just as the sensor elements are formed as thin or thick film resistors onto the substrate.
Claim 33
Dependent Claim
29 words
Method according to claim 28 or 29, characterized in that the insulating layer is in the form of a thin enamel layer deposited by means of an enamelling process.
Claim 34
Dependent Claim
35 words
Method according to claim 28 or 29, characterized in that the insulating layer is deposited in the form of a thin layer by means of sputtering, evaporating in vacuum or depositing within a galvanic bath.
Claim 35
Dependent Claim
50 words
Method according to one of the claims 28-31 inclusive, characterized in that the material of said resistors is deposited by means of deposition in vacuum or sputtering or deposition within a galvanic bath, whereafter locally material is removed by etching or laser processing until the desired resistance shape is obtained.
Claim 36
Dependent Claim
79 words
Method for fabricating a fluid flow measuring device according to one of the claims 22-26, characterized in that the fluid flow measuring channel is made of aluminium onto which a layer of aluminium oxide is formed as insulating layer, onto which the sensor elements, the heater elements as well as components of the measuring circuit are realized in the form of thin or thick film circuits whereafter the insulating body is formed around said thin or thick film elements.
Claim 37
Dependent Claim
29 words
Method according to one of the claims 28-33, characterized in that the insulating body is at least partly fabricated from natural fibers such as glass wool or rockwool fibers.
Claim 38
Dependent Claim
216 words
Fluid flow measuring device for measuring the flow rate of fluid flowing through a thermically conducting fluid measuring channel comprising sensor elements positioned onto the outer wall of the measuring channel and thermically insulated from the environment by an insulating body, which sensor elements can be heated for creating a temperature gradient as a function of the fluid flow rate, which temperature gradient can be converted into an electrical measuring signal using a bridge circuit, characterized in that said bridge circuit comprises four sensor elements which two by two are connected in series and are positioned onto the fluid measuring channel such that of each series circuit one element is positioned onto a first section of the fluid measuring channel upstream in relation to a second section of the fluid measuring channel onto which the other element of the respective series circuit is positioned, whereby the downstream end of each series circuit is connected to the upstream end of the respective other series circuit and the electrical measuring signal is available at the junctions within said series circuits and the sensor elements are formed by resistance elements which in the form of thin layers are realized onto the electrically insulating fluid measuring channel respectively onto a thin insulating layer onto the electrically conducting fluid measuring channel.
Claim 39
Dependent Claim
216 words
Fluid flow measuring device for measuring the flow rate of fluid flowing through a thermically conducting fluid measuring channel comprising sensor elements positioned onto the outer wall of the measuring channel and thermically insulated from the environment by an insulating body, which sensor elements can be heated for creating a temperature gradient as a function of the fluid flow rate, which temperature gradient can be converted into an electrical measuring signal using a bridge circuit, characterized in that said bridge circuit comprises four sensor elements which two by two are connected in series and are positioned onto the fluid measuring channel such that of each series circuit one element is positioned onto a first section of the fluid measuring channel upstream in relation to a second section of the fluid measuring channel onto which the other element of the respective series circuit is positioned, whereby the downstream end of each series circuit is connected to the upstream end of the respective other series circuit and the electrical measuring signal is available at the junctions within said series circuits and the sensor elements are formed by resistance elements which in the form of thin layers are realized onto the electrically insulating fluid measuring channel respectively onto a thin insulating layer onto the electrically conducting fluid measuring channel.
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