WO1998026261A1 - Pressure transducer - Google Patents
Pressure transducer Download PDFInfo
- Publication number
- WO1998026261A1 WO1998026261A1 PCT/IB1997/001561 IB9701561W WO9826261A1 WO 1998026261 A1 WO1998026261 A1 WO 1998026261A1 IB 9701561 W IB9701561 W IB 9701561W WO 9826261 A1 WO9826261 A1 WO 9826261A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- membrane
- layer
- glass
- chamber
- pressure transducer
- Prior art date
Links
- 239000012528 membrane Substances 0.000 claims abstract description 63
- 239000011521 glass Substances 0.000 claims abstract description 46
- 238000000034 method Methods 0.000 claims description 5
- 229910010293 ceramic material Inorganic materials 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 6
- 238000002485 combustion reaction Methods 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 244000045947 parasite Species 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/04—Means for compensating for effects of changes of temperature, i.e. other than electric compensation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/02—Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring device; Zero-setting means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
- G01L9/0075—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance using a ceramic diaphragm, e.g. alumina, fused quartz, glass
Definitions
- the invention concerns a pressure transducer comprising a transducer housing, a first membrane, a second membrane, the membranes being arranged at a distance from each other and the transducer housing, and electrodes for measuring the movement of the membranes.
- Such duplex- or multi-membrane transducers are previously known.
- the purpose of the multi-membrane structure is to eliminate the effect of a number of physical quantities which may give rise to erroneous measurement results when the pressure of a medium is measured.
- Physical quantities which may have an effect on a pressure-sensing membrane, either directly or indirectly via the transducer housing comprise, among others, temperature, ambient pressure, acceleration caused by, e.g. shocks, blows or gravitation, as well as the self-resonant frequency of the membrane.
- the aim of the present invention is to achieve a pressure transducer which eliminates the above-cited drawbacks and which in addition to simpler manufacture enables the measurement of low or extremely low pressures with great accuracy within a very low pressure interval.
- the aim is attained by means of a pressure transducer according to the invention, such a pressure transducer being mainly characterized by the first membrane and the second membrane being connected to one another by means of an intermediate glass joint, the glass joint comprising a first layer and a second layer, the first layer consisting of high temperature glass and the second layer of low temperature glass.
- the invention is based on the notion of achieving as small a distance between the membranes as possible, this being necessary in view of strength data and the fact that the resolution of the transducer is proportional to the movement through the basic distance between the electrodes.
- This is achieved by connecting the membranes to one another by means of a glass joint consisting of two layers formed in two steps. First, the high temperature glass is applied onto one membrane, whereafter the low temperature glass is applied onto the high temperature glass.
- the glass and the ceramic material of the transducer housing advantageously have the same temperature coefficient.
- the difference between the melting points of the two glasses is preferably significant enough for the high temperature glass to remain intact during the application of the low temperature glass.
- the pressure transducer advantageously comprises three chambers whereby the transducer housing and the first membrane delimit a first chamber, the first membrane and the second membrane delimit a second chamber and the second membrane and the transducer housing delimit a third chamber, whereby the third chamber is furnished with an opening for receiving the medium whose pressure is to be measured and the first chamber and the second chamber exhibit a reference vacuum.
- the first chamber and the second chamber are advantageously in contact with one another through an opening in the first membrane, the opening maintaining a reference vacuum in said chambers in a simple way.
- the chambers can naturally also be separately furnished with a reference vacuum.
- the invention also concerns a method for connecting pressure transducer membranes to one another with a minimal mutual distance, the method being mainly characterized by applying a joint of high temperature glass onto one of the membranes by means of kiln combustion and a joint of low temperature glass is applied on the high temperature glass in a separate successive kiln combustion step, whereafter the other membrane is applied onto the joint of low temperature glass.
- Fig. 1 depicts an embodiment of the pressure transducer according to the invention
- Fig. 2 depicts the connection of the membranes to one another in detail.
- the transducer housing of the pressure transducer is marked with the reference numeral 1.
- the transducer housing encompasses a first membrane 2 and a second membrane 6.
- the membranes 2 , 6 are arranged at a distance from the membrane housing 1 and at an extremely small mutual distance by means of a glass joint 5.
- a first chamber 31 is formed between the transducer housing 1 and the first membrane 2 and a second chamber 32 is formed between the first membrane 2 and the second membrane 6, which chambers are preferably connected to each other through an opening 4 in the first membrane 2.
- the chambers can naturally also be held separate.
- the first chamber 31 and the second chamber 32 preferably have a reference vacuum.
- a third chamber 33 is formed between the second membrane 6 and the transducer housing 1, the chamber being furnished with an opening 9 or a measurement orifice in the transducer housing 1 for receiving the medium whose pressure is to be measured.
- the pressure measurement takes place differentially between the two membranes 2,6 by means of electrodes (not shown) arranged on the same.
- the second membrane 6 is affected partly by the pressure of the current medium and partly by parasite physical quantities such as temperature, ambient pressure, acceleration caused by e.g. shocks, blows or gravitation, as well as the self- resonant frequency of the membrane.
- the first membrane 2 is only affected by these parasite quantities, whereby the real current pressure is obtained by means of the above-cited differential measurement.
- Fig. 2 shows how the first membrane 2 and the second membrane 6 are connected to one another by means of a glass joint 5 comprising a first layer 7 of high temperature glass and a second layer 8 of low temperature glass.
- the connection is performed by applying the high temperature glass layer 7 onto the first membrane 2 in a first kiln combustion step, whereafter the low temperature glass layer 8 is applied onto the high temperature glass joint 7 in a second kiln combustion step.
- the membranes as well as the high temperature glass and the low temperature glass should have the same temperature coefficient, whereby the melting point of the high temperature glass should be higher than that of the low temperature glass such that the high temperature glass remains intact when the low temperature glass is kilned. With such a glass joint consisting of two layers and effected in two steps the distance between the membranes can be minimized.
- the pressure transducer including the membranes is advantageously produced of ceramic material, for example aluminium oxide.
- the above-described pressure transducer is suited for instance for the measurement of pressure from 1 torr FS (Full Scale) to 0.1 torr FS (Full Scale), whereby the distance between the membranes can be between 5 and 20 ⁇ m.
- the membrane thickness can hereby be, for example, in the range from 50 to 150 ⁇ m.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention concerns a pressure transducer comprising a transducer housing (1), a first membrane (2), a second membrane (6) and electrodes for measuring the movement of the membranes. In order to enable precision measurement of low pressure within a low pressure interval, the first membrane (2) and the second membrane (6) are connected to one another at an extremely small mutual distance by means of an intermediate glass joint (5) comprising a first layer of high temperature glass and a second layer of low temperature glass.
Description
Pressure transducer
The invention concerns a pressure transducer comprising a transducer housing, a first membrane, a second membrane, the membranes being arranged at a distance from each other and the transducer housing, and electrodes for measuring the movement of the membranes.
Such duplex- or multi-membrane transducers are previously known. The purpose of the multi-membrane structure is to eliminate the effect of a number of physical quantities which may give rise to erroneous measurement results when the pressure of a medium is measured. Physical quantities which may have an effect on a pressure-sensing membrane, either directly or indirectly via the transducer housing, comprise, among others, temperature, ambient pressure, acceleration caused by, e.g. shocks, blows or gravitation, as well as the self-resonant frequency of the membrane.
Examples of known pressure transducers can be found in the patent specifications US 3,962,921, US 4,689,999 and US 4,974,117.
However, these known transducers are of a very complicated construction which easily exposes them to defects and malfunction. The aim of the present invention is to achieve a pressure transducer which eliminates the above-cited drawbacks and which in addition to simpler manufacture enables the measurement of low or extremely low pressures with great accuracy within a very low pressure interval. The aim is attained by means of a pressure transducer according to the invention, such a pressure transducer being mainly characterized by the first membrane and the second membrane being connected to one another by means of an intermediate glass joint, the glass joint comprising a first layer and a second layer, the first layer consisting of high temperature glass and the second layer of low temperature glass.
The invention is based on the notion of achieving as small a distance between the membranes as possible, this being necessary in view of strength data and the fact that the resolution of the transducer is proportional to the movement through the basic distance between the electrodes. This is achieved by connecting the membranes to one another by means of a glass joint consisting of two layers formed in two steps. First, the high temperature glass is applied onto one membrane, whereafter the low temperature glass is applied onto the high temperature glass. The glass and the ceramic material of the transducer housing advantageously have the same temperature coefficient. The difference between the melting points of the two glasses is preferably significant enough for the high temperature glass to remain intact during the application of the low temperature glass.
The pressure transducer advantageously comprises three chambers whereby the transducer housing and the first membrane delimit a first chamber, the first membrane and the second membrane delimit a second chamber and the second membrane and the transducer housing delimit a third chamber, whereby the third chamber is furnished with an opening for receiving the medium whose pressure is to be measured and the first chamber and the second chamber exhibit a reference vacuum. The first chamber and the second chamber are advantageously in contact with one another through an opening in the first membrane, the opening maintaining a reference vacuum in said chambers in a simple way. The chambers can naturally also be separately furnished with a reference vacuum.
The invention also concerns a method for connecting pressure transducer membranes to one another with a minimal mutual distance, the method being mainly characterized by applying a joint of high temperature glass onto one of the membranes by means of kiln combustion and a joint of low temperature glass is
applied on the high temperature glass in a separate successive kiln combustion step, whereafter the other membrane is applied onto the joint of low temperature glass. In the following the invention is described in closer detail with reference to the annexed schematic drawings where
Fig. 1 depicts an embodiment of the pressure transducer according to the invention, and Fig. 2 depicts the connection of the membranes to one another in detail.
In Fig. 1, the transducer housing of the pressure transducer is marked with the reference numeral 1. The transducer housing encompasses a first membrane 2 and a second membrane 6. The membranes 2 , 6 are arranged at a distance from the membrane housing 1 and at an extremely small mutual distance by means of a glass joint 5. A first chamber 31 is formed between the transducer housing 1 and the first membrane 2 and a second chamber 32 is formed between the first membrane 2 and the second membrane 6, which chambers are preferably connected to each other through an opening 4 in the first membrane 2. The chambers can naturally also be held separate. The first chamber 31 and the second chamber 32 preferably have a reference vacuum. A third chamber 33 is formed between the second membrane 6 and the transducer housing 1, the chamber being furnished with an opening 9 or a measurement orifice in the transducer housing 1 for receiving the medium whose pressure is to be measured. The pressure measurement takes place differentially between the two membranes 2,6 by means of electrodes (not shown) arranged on the same. The second membrane 6 is affected partly by the pressure of the current medium and partly by parasite physical quantities such as temperature, ambient pressure, acceleration caused by e.g. shocks, blows or gravitation, as well as the self- resonant frequency of the membrane. The first membrane 2
is only affected by these parasite quantities, whereby the real current pressure is obtained by means of the above-cited differential measurement.
Fig. 2 shows how the first membrane 2 and the second membrane 6 are connected to one another by means of a glass joint 5 comprising a first layer 7 of high temperature glass and a second layer 8 of low temperature glass. The connection is performed by applying the high temperature glass layer 7 onto the first membrane 2 in a first kiln combustion step, whereafter the low temperature glass layer 8 is applied onto the high temperature glass joint 7 in a second kiln combustion step. The membranes as well as the high temperature glass and the low temperature glass should have the same temperature coefficient, whereby the melting point of the high temperature glass should be higher than that of the low temperature glass such that the high temperature glass remains intact when the low temperature glass is kilned. With such a glass joint consisting of two layers and effected in two steps the distance between the membranes can be minimized.
The pressure transducer including the membranes is advantageously produced of ceramic material, for example aluminium oxide. The above-described pressure transducer is suited for instance for the measurement of pressure from 1 torr FS (Full Scale) to 0.1 torr FS (Full Scale), whereby the distance between the membranes can be between 5 and 20 μm. The membrane thickness can hereby be, for example, in the range from 50 to 150 μm. The drawing and the related description are intended to illustrate the basic idea of the invention. The details of the pressure transducer may vary within the scope of the claims.
Claims
1. A pressure transducer comprising a transducer housing (1) , a first membrane (2) , a second membrane (6) , whereby the membranes are arranged at a distance from one another and the transducer housing, and electrodes for measuring the movement of the membrane, characterized in that the first membrane (2) and the second membrane (6) are connected to each other by means of an intermediate glass joint (5, 7, 8), the glass joint (5) comprises a first layer (7) and a second layer (8) , and that the first layer (7) consists of high temperature glass and the second layer (8) of low temperature glass.
2. The pressure transducer according to claim 1, characterized in that the first layer (7) and the second layer (8) of the glass joint (5) have the same temperature coefficient.
3. The pressure transducer according to claim 1 or 2, characterized in that the first layer (7) and the second layer (8) of the glass joint (5) have different melting points.
4. The pressure transducer according to any one of the previous claims, characterized in that the pressure transducer is produced of ceramic material, whereby the first layer (7) and the second layer (8) of the glass joint (5) have the same temperature coefficient as the ceramic material.
5. The pressure transducer according to claim 1, characterized in that the transducer housing (1) and the first membrane (2) delimit a first chamber (31) , the first membrane (2) and the second membrane (6) delimit a second chamber (32) and the second membrane (6) and the transducer housing (1) delimit a third chamber (33), whereby the third chamber (33) has an orifice (9) for receiving the medium whose pressure is to be measured.
6. The pressure transducer according to claim 5, characterized in that the first chamber (31) and the second chamber (32) are connected to one another through an opening (4) in the first membrane (31) .
7. The pressure transducer according to claim 5 or 6, characterized in that the first chamber (31) and the second chamber (32) have a reference vacuum.
8. A method for connecting pressure transducer membranes to one another at an extremely small mutual distance, characterized in that a layer (7) of high temperature glass is applied onto one membrane (2) by means of kilning and a layer (8) of low temperature glass is applied onto the high temperature glass by means of a separate kilning, whereafter the second membrane (6) is applied onto the layer (8) of low temperature glass.
9. The method according to claim 8, characterized in that the membranes (2,6) and the glass layers (7,8) have the same temperature coefficient.
10. The method according to claim 8 or 9, characterized in that the glass layers (7,8) have different melting points.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI965017A FI101426B (en) | 1996-12-13 | 1996-12-13 | pressure sensor |
| FI965017 | 1996-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1998026261A1 true WO1998026261A1 (en) | 1998-06-18 |
Family
ID=8547271
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB1997/001561 WO1998026261A1 (en) | 1996-12-13 | 1997-12-12 | Pressure transducer |
Country Status (2)
| Country | Link |
|---|---|
| FI (1) | FI101426B (en) |
| WO (1) | WO1998026261A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2317294A1 (en) * | 2009-11-02 | 2011-05-04 | VEGA Grieshaber KG | Measuring cell |
| EP2806258A1 (en) * | 2013-05-20 | 2014-11-26 | Nxp B.V. | Differential pressure sensor |
| EP2362203A3 (en) * | 2010-02-27 | 2014-12-24 | Codman Neurosciences Sarl | Apparatus and method for minimizing drift of a piezo-resisitive pressure sensor due to the progressive release of mechanical stress over time |
| CN110036269A (en) * | 2016-12-08 | 2019-07-19 | 梅斯瑞士公司 | Pressure sensor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4689999A (en) * | 1985-07-26 | 1987-09-01 | The Garrett Corporation | Temperature compensated pressure transducer |
| US5561247A (en) * | 1993-03-30 | 1996-10-01 | Honda Motor Co., Ltd. | Pressure sensor |
-
1996
- 1996-12-13 FI FI965017A patent/FI101426B/en not_active IP Right Cessation
-
1997
- 1997-12-12 WO PCT/IB1997/001561 patent/WO1998026261A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4689999A (en) * | 1985-07-26 | 1987-09-01 | The Garrett Corporation | Temperature compensated pressure transducer |
| US5561247A (en) * | 1993-03-30 | 1996-10-01 | Honda Motor Co., Ltd. | Pressure sensor |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2317294A1 (en) * | 2009-11-02 | 2011-05-04 | VEGA Grieshaber KG | Measuring cell |
| EP2362203A3 (en) * | 2010-02-27 | 2014-12-24 | Codman Neurosciences Sarl | Apparatus and method for minimizing drift of a piezo-resisitive pressure sensor due to the progressive release of mechanical stress over time |
| EP2806258A1 (en) * | 2013-05-20 | 2014-11-26 | Nxp B.V. | Differential pressure sensor |
| US9726561B2 (en) | 2013-05-20 | 2017-08-08 | Ams International Ag | Differential pressure sensor with a capacitive read out system |
| CN110036269A (en) * | 2016-12-08 | 2019-07-19 | 梅斯瑞士公司 | Pressure sensor |
| CN110036269B (en) * | 2016-12-08 | 2021-04-06 | 梅斯瑞士公司 | Pressure sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| FI101426B1 (en) | 1998-06-15 |
| FI101426B (en) | 1998-06-15 |
| FI965017A0 (en) | 1996-12-13 |
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