GB2397350A - Fluid differential pressure measurement device protection circuit - Google Patents
Fluid differential pressure measurement device protection circuit Download PDFInfo
- Publication number
- GB2397350A GB2397350A GB0300971A GB0300971A GB2397350A GB 2397350 A GB2397350 A GB 2397350A GB 0300971 A GB0300971 A GB 0300971A GB 0300971 A GB0300971 A GB 0300971A GB 2397350 A GB2397350 A GB 2397350A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pressure
- fuse
- fluid
- differential pressure
- lines
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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
- G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
- G01L19/0618—Overload protection
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
A fluid protection circuit for a differential pressure measurement, e.g. transducer type, device 1. The circuit includes first and second pressure lines 2 and 3 for feeding fluid from pressurised, e.g. gas, system 4 to the measurement device and a pressure fuse 5 in fluid communication with the pressure lines 2 and 3 and connected in parallel with the device. If the differential pressure across the fuse exceeds the differential pressure rating of the device then it automatically operates to place the pressure lines 2 and 3 in fluid communication with each other and reduces the differential pressure between the pressure lines and prevents permanent damage to the device. Restrictors R Ü , R Þ prevent transient pressure spikes reaching the device before fuse operation and restrictors R ý , R4 ensure the fuse responds only to excess static pressure. The fuse may be of rupturable diaphragm, mechanical one-shot or resettable type.
Description
TITLE
Fluid protection circuits
DESCRIPTION
Technical Field
The invention relates to fluid protection circuits, and in particular to fluid protection circuits for use with differential pressure measurement devices.
Background Art
Differential pressure measurement devices are well known. Typically, such devices have a specific differential pressure rating. The differential pressure rating can sometimes be very low, even if the device is designed to operate at very high static pressures. If one of the two pressure lines feeding the device breaks, begins to leak or becomes blocked then the difference between the pressure in that line and the pressure in the other line may exceed the differential pressure rating of the device.
The differential pressure rating of the device can also be exceeded if one of the two pressure lines experiences a large dynamic or transient pressure spike. Repeated or prolonged exposure to differential pressures larger than the specific differential pressure rating can cause permanent damage to the device.
Summarv of the Invention The invention, which seeks to overcome the problems described above, provides a fluid protection circuit for a differential pressure measurement device, the circuit comprising first and second pressure lines for feeding a fluid to the differential pressure measurement device, and a pressure fuse in fluid communication with the first and second pressure lines and connected in parallel with the differential pressure measurement device, wherein the pressure fuse automatically operates to place the first and second pressure lines in fluid communication with each other if the differential pressure between the first and second pressure lines exceeds a predetermined limit. - 2
Under normal operating conditions the first and second pressure lines are not in fluid communication with each other. However, if the first pressure line develops a sudden blockage or leak which causes the pressure fuse to sense differential pressure between the first and second pressure lines exceeding the predetermined limit then the pressure fuse will operate quickly and automatically to place the first and second pressure lines in fluid communication with each other. Fluid in the second pressure line can then flow into the first pressure line to equalise the pressure in the two pressure lines and reduce the differential pressure seen by the differential pressure measurement device.
Similarly, if the first pressure line experiences a large dynamic or transient pressure spike which results in the differential pressure between the first and second pressure lines exceeding the predetermined limit then the pressure fuse will operate quickly and automatically to place the first and second pressure lines in fluid communication with each other. Fluid in the first pressure line can then flow into the second pressure line to equalise the pressure in the two pressure lines and reduce the differential pressure seen by the differential pressure measurement device.
It will be readily appreciated that the pressure fuse operates in a similar way as an electrical fuse to protect the differential pressure measurement device and reduce the risk of it being permanently damaged.
The pressure fuse may be of a type that cannot be reset such as a rupturable membrane or diaphragm or a mechanical "one-shot" device. However, the pressure fuse may also be of a type that can be manually or automatically reset once the differential pressure between the first and second pressure lines falls below the predetermined limit.
The predetermined limit is set according to specific fluid circuit requirements and may be the same as, more than or less than, the differential pressure rating of the differential pressure measurement device.
At least one fluid restrictor may be provided in one of the first and second pressure lines between the pressure fuse and the differential pressure measurement device. It is - 3 generally preferred that a first fluid restrictor is provided in the first pressure line between the pressure fuse and the differential pressure measurement device and that a second fluid restrictor is provided in the second pressure line between the pressure fuse and the differential pressure measurement device.
The function of the at least one fluid restrictor provided between the pressure fuse and the differential pressure measurement device is to dampen any dynamic or transient pressure spikes which might otherwise damage the differential pressure measurement device before the pressure fuse has time to operate to place the first and second pressure lines in fluid communication with each other. However, the at least one fluid restrictor does not provide any protection against steady-state or static differential pressures that exceed the predetermined limit.
At least one fluid restrictor may also be provided between the pressure fuse and one of the first and second pressure lines. It is generally preferred that a first (or third) fluid restrictor is provided between the pressure fuse and the first pressure line and that a second (or fourth) fluid restrictor is provided between the pressure fuse and the second pressure line.
The function of the at least one fluid restrictor provided between the pressure fuse and one of the first and second pressure lines is to protect the pressure fuse from any dynamic or transient pressure spikes. This ensures that the pressure fuse does not operate to place the first and second pressure lines in fluid communication with each other unless there is a steady-state or static differential pressure that exceeds the predetermined limit.
The addition of the fluid restrictors makes the fluid protection circuit more reliable for both dynamic or transient and steady-state situations. It will be readily appreciated that the fluid restrictors protect both the differential pressure measurement device and the pressure fuse against dynamic or transient pressure spikes, whilst the differential pressure measurement device itself is protected against large steady- state or static differential pressures by the pressure fuse. - 4
The differential pressure measurement device can be of a transducer type.
Drawing Figure I is a fluid protection circuit according to the invention.
Figure 1 shows a fluid protection circuit for a differential pressure measurement device (the "device") 1. Two pressure lines 2 and 3 feed gas from a pressurised system 4 to the device 1. The pressure of the gas in the pressure lines 2 and 3 is denoted by PI and P2 respectively. The device I has a specific differential pressure rating.
A pressure fuse 5 is positioned in fluid communication with the pressure lines 2 and 3 so that it is connected in parallel with the device 1. Because the pressure fuse 5 is connected in parallel with the device 1, the differential pressure across the pressure fuse will be exactly the same as the differential pressure seen by the device. The pressure fuse 5 contains a membrane (not shown) that is designed to rupture or fail if the differential pressure across the pressure fuse exceeds the specific differential pressure rating of the device 1.
In normal operation, the first and second pressure lines 2 and 3 are not in fluid communication with each other and are separated by the pressure fuse 5. However, if the first pressure line 2 develops a sudden blockage, for example, then the pressure PI of the gas in the first pressure line will start to fall. If this fall in pressure means that the differential pressure across the pressure fuse 5 exceeds the specific pressure rating of the device 1 then the membrane (not shown) will automatically rupture to allow gas in the second pressure line 3 to flow into the first pressure line 2 through the pressure fuse 5 as shown by the dotted line. This gas flow equalises the pressures PI and P2 in the first and second pressure lines 2 and 3 to reduce the differential pressure seen by the device I and bring it back below the specific pressure rating. The pressure fuse 5 therefore protects the device 1 and reduces the risk of it being permanently damaged. - 5
A first fluid restrictor Rat is provided in the first pressure line 2 between the pressure fuse 5 and the device 1. A second fluid restrictor R2 is similarly provided in the second pressure line 3 between the pressure fuse 5 and the device 1. The first and second fluid restrictors Rut and R2 dampen any dynamic or transient pressure spikes which might otherwise damage the device 1 before the pressure fuse 5 has time to operate to place the first and second pressure lines 2 and 3 in fluid communication with each other.
Third and fourth fluid restrictors R3 and R4 are provided between the pressure fuse 5 and the first and second pressure lines 2 and 3. They protect the pressure fuse 5 from any dynamic or transient pressure spikes and ensure that the pressure fuse does not operate to place the first and second pressure lines 2 and 3 in fluid communication with each other unless there is a steady-state or static differential pressure that exceeds the specific pressure rating of the device 1. - 6
Claims (9)
- l. A fluid protection circuit for a differential pressure measurement device, the circuit comprising: first and second pressure lines for feeding a fluid to the differential pressure measurement device; and a pressure fuse in fluid communication with the first and second pressure lines and connected in parallel with the differential pressure measurement device, wherein the pressure fuse automatically operates to place the first and second pressure lines in fluid communication with each other if the differential pressure between the first and second pressure lines exceeds a predetermined limit.
- 2. A fluid protection circuit according to claim l, wherein the pressure fuse cannot be reset.
- 3. A fluid protection circuit according to claim 2, wherein the pressure fuse contains a diaphragm that ruptures if the differential pressure between the first and second pressure lines exceeds the predetermined limit.
- 4. A fluid protection circuit according to claim l, wherein the pressure fuse can be reset so that the first and second pressure lines are no longer in fluid communication with each other.
- 5. A fluid protection circuit according to claim 4, wherein the pressure fuse is manually reset.
- 6. A fluid protection circuit according to claim 4, wherein the pressure fuse is automatically reset when the differential pressure between the first and second pressure lines falls below the predetermined limit.
- 7. A fluid protection circuit according to any preceding claim, further comprising at least one fluid restrictor provided in one of the first and second pressure lines between the pressure fuse and the differential pressure measurement device. - 7
- 8. A fluid protection circuit according to any preceding claim, further comprising at least one fluid restrictor provided between the pressure fuse and one of the first and second pressure lines.
- 9. A fluid protection circuit substantiallyas herein described with reference to the drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0300971A GB2397350A (en) | 2003-01-16 | 2003-01-16 | Fluid differential pressure measurement device protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0300971A GB2397350A (en) | 2003-01-16 | 2003-01-16 | Fluid differential pressure measurement device protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0300971D0 GB0300971D0 (en) | 2003-02-19 |
| GB2397350A true GB2397350A (en) | 2004-07-21 |
Family
ID=9951245
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0300971A Withdrawn GB2397350A (en) | 2003-01-16 | 2003-01-16 | Fluid differential pressure measurement device protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2397350A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106052948A (en) * | 2015-04-10 | 2016-10-26 | 株式会社日立制作所 | Pressure transmitter device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1188437A (en) * | 1967-11-02 | 1970-04-15 | Camco Inc | Improvements in Relief Valves for Protecting a Differential Pressure Transducer |
| JPS5467479A (en) * | 1977-11-09 | 1979-05-30 | Toshiba Corp | Differencial pressure converter |
| GB2091883A (en) * | 1981-01-24 | 1982-08-04 | Skil Controls Ltd | Differential pressure transducer |
| US4668889A (en) * | 1986-06-06 | 1987-05-26 | Adams Donald L | Static overpressure protection system for differential pressure transducer |
| JPH05203521A (en) * | 1992-01-23 | 1993-08-10 | Hitachi Constr Mach Co Ltd | Differential pressure detecting apparatus |
| EP0565271A1 (en) * | 1992-03-27 | 1993-10-13 | Pall Corporation | Differential pressure transducer assembly |
| DE19503488A1 (en) * | 1995-02-03 | 1996-08-08 | Norbert Martin | Differential pressure monitor for use in feed line of liquid or gas |
-
2003
- 2003-01-16 GB GB0300971A patent/GB2397350A/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1188437A (en) * | 1967-11-02 | 1970-04-15 | Camco Inc | Improvements in Relief Valves for Protecting a Differential Pressure Transducer |
| JPS5467479A (en) * | 1977-11-09 | 1979-05-30 | Toshiba Corp | Differencial pressure converter |
| GB2091883A (en) * | 1981-01-24 | 1982-08-04 | Skil Controls Ltd | Differential pressure transducer |
| US4668889A (en) * | 1986-06-06 | 1987-05-26 | Adams Donald L | Static overpressure protection system for differential pressure transducer |
| JPH05203521A (en) * | 1992-01-23 | 1993-08-10 | Hitachi Constr Mach Co Ltd | Differential pressure detecting apparatus |
| EP0565271A1 (en) * | 1992-03-27 | 1993-10-13 | Pall Corporation | Differential pressure transducer assembly |
| DE19503488A1 (en) * | 1995-02-03 | 1996-08-08 | Norbert Martin | Differential pressure monitor for use in feed line of liquid or gas |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106052948A (en) * | 2015-04-10 | 2016-10-26 | 株式会社日立制作所 | Pressure transmitter device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0300971D0 (en) | 2003-02-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |