CA2050418A1 - Differential pressure sensing pilot - Google Patents
Differential pressure sensing pilotInfo
- Publication number
- CA2050418A1 CA2050418A1 CA002050418A CA2050418A CA2050418A1 CA 2050418 A1 CA2050418 A1 CA 2050418A1 CA 002050418 A CA002050418 A CA 002050418A CA 2050418 A CA2050418 A CA 2050418A CA 2050418 A1 CA2050418 A1 CA 2050418A1
- Authority
- CA
- Canada
- Prior art keywords
- diaphragm
- stem
- differential pressure
- pressure sensor
- sensor assembly
- 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.)
- Abandoned
Links
- 239000012530 fluid Substances 0.000 abstract description 8
- 230000007935 neutral effect Effects 0.000 abstract description 3
- 238000011144 upstream manufacturing Methods 0.000 description 10
- 239000007789 gas Substances 0.000 description 7
- 238000005259 measurement Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920006074 Nylatron® Polymers 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910000078 germane Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical compound FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 1
Abstract
- 11 -DIFFERENTIAL PRESSURE SENSING PILOT ABSTRACT OF THE DISCLOSURE A differential pressure sensor assembly for use on flow lines. A diaphragm is exposed to both high and low pressure on opposite sides of the diaphragm and respective diaphragm plates maintain the position of and provide support for the diaphragm, the diaphragm and diaphragm plates being mounted on a stem. When the pressure differential changes, the stem on which the diaphragm is mounted moves under the influence of the diaphragm. A spring is utilised to counteract the pressure differential on opposite sides of the diaphragm and to "centre" the diaphragm in its neutral position. The movement of the stem initiates the operation of a pilot valve which will shut down the fluid flow in the flow line. specs\bar3560.1&2
Description
DIFFERENTIAL PRESSURE SENSING PILOT
INTRODUCTION
This invention relates to a di~ferential pressure sensor and, more particularly, to a differential pressure sensor for use in pipeline flow measurements of highly compressed and heavy gases such as CO2.
BACKGROUND OF THE INVENTIQN
It is important in pipelines to sense if a break has occurred or if leakage is taking place. Besides the obvious loss of pipeline fluid such as oil and gas, which can be costly, environmental and safety concerns are now paramount consi~erations and it i5 important that the pipeline be shut down as soon as possible if leakage is present.
Flow measurements are also required for pricing the fluids which are displaced through the pipeline. It is, therefore, important to ensure that the guantity of fluid which has passed through the pipeline be correct.
;
Two types of measurements have typically been used to determine the quantity of fluid passing through a ~low line. The e are pressure and flow measurements.
Measuring such changes, however, is not a simple or inexpensive task, particularly when the fluid is gas.
This is so because if leakage occurs, the gas in the pipeline expands to occupy the volume of gas lost to - leakage with the result that the pressure drop may be minimal. In any event, the apparatus required for the measur~ment of such pressure and flow is sophisticated and 3~5 expensive.
:; ~
:~
, ' SUMMARY OF THE INVENTION
According to the present invention, there is provided a differential pressure sensor assembly comprising a stem, a diaphragm mounted on said stem, first and second diaphragm plates mounted on said stem with said diaphragm being positioned between said diaphragm plates, at least one of said diaphragm plates providing support for said diaphragm across a substantial portion of its area, spring means acting on said stem, said diaphragm being exposed to high and low pressures on opposite sides of said diaphragm, said stem being movable with said diaphragm and said diaphragm plates upon a predetermined change in said pressure differential between opposite sides of said diaphragm.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
An embodiment of the invention will now be described, by way of example only, with the usa of drawings in which:
Figure 1 is a partial view of a pipeline including the flow orifice and the differential pressure sensor assembly according to the invention; and Figure 2 is an enlarged sectional view of the differential pressure assembly according to the invention.
DESCRIPTION OF SPECIFIC EMBODIMENT
Referring now to the drawings, a pip~ or flow line is generally illustrated at 10 in Figure 1 which flow lin~ is conveniently used for gas or liquids. It ~omprises a higher pressure or upstream end 11, a lower -: ' '' ., - ., '. : , .: . . -~ , , . , ., : -. . : . ... . .
pressure or downstream end 12, an upstream flange 13 and a downstream flange 14. Upstream flange 13 and downstream flange 14 are connected using bolted connections 20 as is usual.
A flow measuring orifice 21, conveniently a wedge restriction, is positioned between the upstream and downstream flanges 13, 14, respectively. The orifice 21, through which the pipeline fluid must flow, is used to create the pressure differential between the upstream and downstream flanges 13, 14.
An upstream port 22 and a downstream port 23 are connected di.rectly into the pipeline fluid at their respective locations. A first coupling 24 runs between khe upstream port 22 and the hiyh pressure inlet port ~0 of the dif~erential pressure sensor assembly generally shown at 31 (Figure 2). A second coupling 32 runs between the downstream port 23 and the low pressure inlet port 33 of the differential pressure sensor assembly 31.
Referring now specifically to the differential pressurP sensor assembly 31 as illustrated in Figure 2, a spring side flange 34 and a valve side flange 40 are connected by cap screws 41. A spring housing 42 is threadeAly connected to a complimentary hole 43 of spring side flange 34 and an O-ring 73 is positioned as indicated to seal against pressure loss. A valve side adapter 44 is threadedly inserted in a complimentary hole 50 in valve side flange 40 and an O-ring 74 is positioned as indicated to seal against pressure loss from this area. An O-ring 51 is also positioned in a complimentary recess in spring ~ide flange 34 and extends about the inner periphery of the spring side 1ange 34 in contact with the val~e side ~lange 40.
.
.
''' '~' ~ . ' . ' : .
:, ~ . , Two diaphragm plates, namely a spring side diaphragm plate 52 and a valve side diaphragm plate 53 are positioned an axial distance apart on the stem 61 betwsen a shoulder 54 and a nut 60 which is threadedly engaged with stem 61. The diaphragm plates 52, 53 provide support for the diaphragm 75 which is positioned between the diaphragm plates 52, 53 as set out hereafter. Stem 61 is connected through a ball joint 62 which is acted on by spring plate 63. Spring plate 63 exerts a downwards force on ball joint 62 by spring 64 which acts betwesn spring plat~ 63 and spring plate 70.
A low friction guide ring 91, conveniently made from NYLATRON or TEFLON material, a low friction seal 92 made from similar material, a seal spacer 93 and a retaining ring 94 are mounted about the stem 61 on opposite sides of the diaphragm 75 and diaphragm plates 52, 53 as illustrated. The objective is to minimize or eliminate metal-to-m~tal contact occurring during movement of the stem 61.
A set screw 71 is threadedly engaged into a - complementary threaded connection in the bottom of stem 61. Set screw 71 may he adjusted upwardly and downwardly with respect to stem 61 for adjustment purposes as will be explained hereafter. An O-ring 72 is positioned about stem 61 between stem 61 and valve side diaphragm plate 53.
Diaphragm 75 is mounted between the spring side diaphragm plate 52 and the valve side diaphragm plate 531 the spring and valve side diaphragm plates 52, 53r respectively, providing support for the diaphragm 75. The diaphragm 75 has a diameter that extends beyond the outside diameter of the diaphra~m plates 52~ 53 and into the area directly between the spring and valve side flanges 34, 40, respectively. Both the high pressure side of the diaphragm 75 and the low pressure side of the diaphragm 75 are of 2 ~
the same area. Accordingly, the force differential created by the difference in force between the two sides of the diaphragm 75 created by the pressure difference between the pressure differential between upstream and downstream flanges 13, 14, respectively, tends to move diaphragm 75 upwardly as viewed in Figure 2 and this force is counteracted by spring 64. A ball 80 acts downwardly on spring plate 70. A spring screw 81 acts on ball 80 and is adjustably and threadedly engaged in plug 82 so as to adjust the position of the diaphragm 75 as will be set out hereafter. Plug 82 is threadedly en~agsd with the spring hsusing 42 in the top of spring housing 42. An O-ring sealed plug 83 acts as a weather seal to prevent the ingress of foreign matter into the assembly 31.
A pilot valve subassembly (not shown) is threadedly engaged with valve side adapter 44. The pilot valve subassembly is used to initiate the operation of a safety valve (not shown) to terminate flow in the flow line 10. Its operation i5 initiated by the actisn of the differential pressure sensor assembly 31 acting on a plunger 90 which is operably connected with the pilot valve assembly. The construction of the pilot valve assembly is not germane to the operation of the differential pressure sensor assembly 31 and, therefore, its construction will not be described.
The plunger 90 of the pilot valve assembly is oparated by the movement of the set screw 7~ with the vertical movement of stem 61. That is, as the stem 61 moves upwardly as will be described in greater detail, set screw 71 will likewise move. This initiates the operation of the pilot valve assembly through plunger 90 which, in turn, will terminate flow in the pipeline lOo .
2 ~
OPERATION
To assemble the differential pressure sensor assembly 31, spring side diaphragm plate 52, diaphragm 75 and valve side diaphragm plate 53 are positioned on stem 61 together with O-ring 72 of valve side diaphragm plate 53. A shoulder 54 and a nut 60 serve to retain the assembly as illustrated in Figure 2~ The valve side flange 40 and the spring side ~lange 34 are then assembled and loosely connected with cap screws 41. The spring housing 42 and the spring side flange 34 are moved downwardly until the valve side diaphragm plate 53 bottoms on the cavity within valve side flange 40. This results in the diaphragm 75 being deflected downwardly and thereby ensuring it is not in contact with the O-ring 51. Cap s~rews 41 are then tightened until the valve side flange 40 fully contacts the spring side flange 34 and O-ring 51 is compressed between the spring and valve side flanges 34, 40, rPspectively.
Under normal flow conditions in flow line 10, the pressure di~ferential between the upstream flange 13 .: and, accordingly, upstream port 22 and downstream flange 14 and, accordingly, downstream port 23, is known.
Likewise, the pressure conditions in the flow line 10 are known. Thus, the differential pressure assembly 31 is designed to provide a '~neutral" position for the diaphragm 75 between spring and valve side diaphra~n plates 52, 53, respectiYely, under such normal conditions as illustrated - 30 and the force in spring 64 may be adjusted by spring screw 81 so as to maintain the diaphragm 75 in such a position~
The position of set screw 71 within stem 61 may also be adjusted so that spring biased plunger 90 of the pilot valve assembly assumes its correct and untriggered position under the normal operating conditions.
An increase in flow rate caused by leakage in the flow line 12 initiates operational movement of the stem 61~ When the pressure acting on the diaphragm 75 increases if, for example, the flow is increased due to a leak in the flow line 12, the stem 61 will move upwardly against spring 64 under the influence of diaphragm 75 and spring side diaphragm plate 52 which provides support for the diaphragm 75 which would otherwise not be capable of resisting the force created by the pressure differential between its two opposite sides.
When the diaphragm 75 is fully moved upwardly against diaphragm plate 52 and diaphragm plate 52 has I'bottomed'~ in the cavity between tha valve and spring side flanges 34, 40 and is abutting spring side flange 34, the only area of diaphragm 75 that is not supported by the spring side diaphragm plate 52 or spring side flange 34 is that area adjacent the bevelled portion 55 of diaphragm plate 52 and that bevelled or cavity area 56 of spring side flange 34. Thus, the force that may be utilised against diaphragm 75 by the pressure differential is increased significantly b~cause of the enhanced ability of the diaphragm 75 to resist the force created by the pressure differential. Upon upwards movement of stem 61 with diaphragm 75, spring biased plunger 90 will likewise move upwardly in contact with set screw 71. The operat}on of the pilot valve will thereby be initiated to terminate pipeline flow.
When the ~low line 10 is returned to its normal operating condition, the differential pressure assembly 31 will automatically return to its neutral operating position.
The dif~erential pressure sensor assembly according to the present invention is typically used with 2 ~
a flow line having a 2-4l' nominal size and which carries a gas under pressure at approximately 2000 p.soi. A
change in pressure differential of 3-12 p.s.i. acxoss the flow measuring orifice will result in appropriate operation of the differential pressure sensor assembly 31 and is sensed thereby.
Many modifications will readily occur to those skilled i~ the art to which the invention relates and the specific embodiment described should be considered as illustrative of the invention only and not as limiting its - scope as defined in accordance with the accompanying claims.
INTRODUCTION
This invention relates to a di~ferential pressure sensor and, more particularly, to a differential pressure sensor for use in pipeline flow measurements of highly compressed and heavy gases such as CO2.
BACKGROUND OF THE INVENTIQN
It is important in pipelines to sense if a break has occurred or if leakage is taking place. Besides the obvious loss of pipeline fluid such as oil and gas, which can be costly, environmental and safety concerns are now paramount consi~erations and it i5 important that the pipeline be shut down as soon as possible if leakage is present.
Flow measurements are also required for pricing the fluids which are displaced through the pipeline. It is, therefore, important to ensure that the guantity of fluid which has passed through the pipeline be correct.
;
Two types of measurements have typically been used to determine the quantity of fluid passing through a ~low line. The e are pressure and flow measurements.
Measuring such changes, however, is not a simple or inexpensive task, particularly when the fluid is gas.
This is so because if leakage occurs, the gas in the pipeline expands to occupy the volume of gas lost to - leakage with the result that the pressure drop may be minimal. In any event, the apparatus required for the measur~ment of such pressure and flow is sophisticated and 3~5 expensive.
:; ~
:~
, ' SUMMARY OF THE INVENTION
According to the present invention, there is provided a differential pressure sensor assembly comprising a stem, a diaphragm mounted on said stem, first and second diaphragm plates mounted on said stem with said diaphragm being positioned between said diaphragm plates, at least one of said diaphragm plates providing support for said diaphragm across a substantial portion of its area, spring means acting on said stem, said diaphragm being exposed to high and low pressures on opposite sides of said diaphragm, said stem being movable with said diaphragm and said diaphragm plates upon a predetermined change in said pressure differential between opposite sides of said diaphragm.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
An embodiment of the invention will now be described, by way of example only, with the usa of drawings in which:
Figure 1 is a partial view of a pipeline including the flow orifice and the differential pressure sensor assembly according to the invention; and Figure 2 is an enlarged sectional view of the differential pressure assembly according to the invention.
DESCRIPTION OF SPECIFIC EMBODIMENT
Referring now to the drawings, a pip~ or flow line is generally illustrated at 10 in Figure 1 which flow lin~ is conveniently used for gas or liquids. It ~omprises a higher pressure or upstream end 11, a lower -: ' '' ., - ., '. : , .: . . -~ , , . , ., : -. . : . ... . .
pressure or downstream end 12, an upstream flange 13 and a downstream flange 14. Upstream flange 13 and downstream flange 14 are connected using bolted connections 20 as is usual.
A flow measuring orifice 21, conveniently a wedge restriction, is positioned between the upstream and downstream flanges 13, 14, respectively. The orifice 21, through which the pipeline fluid must flow, is used to create the pressure differential between the upstream and downstream flanges 13, 14.
An upstream port 22 and a downstream port 23 are connected di.rectly into the pipeline fluid at their respective locations. A first coupling 24 runs between khe upstream port 22 and the hiyh pressure inlet port ~0 of the dif~erential pressure sensor assembly generally shown at 31 (Figure 2). A second coupling 32 runs between the downstream port 23 and the low pressure inlet port 33 of the differential pressure sensor assembly 31.
Referring now specifically to the differential pressurP sensor assembly 31 as illustrated in Figure 2, a spring side flange 34 and a valve side flange 40 are connected by cap screws 41. A spring housing 42 is threadeAly connected to a complimentary hole 43 of spring side flange 34 and an O-ring 73 is positioned as indicated to seal against pressure loss. A valve side adapter 44 is threadedly inserted in a complimentary hole 50 in valve side flange 40 and an O-ring 74 is positioned as indicated to seal against pressure loss from this area. An O-ring 51 is also positioned in a complimentary recess in spring ~ide flange 34 and extends about the inner periphery of the spring side 1ange 34 in contact with the val~e side ~lange 40.
.
.
''' '~' ~ . ' . ' : .
:, ~ . , Two diaphragm plates, namely a spring side diaphragm plate 52 and a valve side diaphragm plate 53 are positioned an axial distance apart on the stem 61 betwsen a shoulder 54 and a nut 60 which is threadedly engaged with stem 61. The diaphragm plates 52, 53 provide support for the diaphragm 75 which is positioned between the diaphragm plates 52, 53 as set out hereafter. Stem 61 is connected through a ball joint 62 which is acted on by spring plate 63. Spring plate 63 exerts a downwards force on ball joint 62 by spring 64 which acts betwesn spring plat~ 63 and spring plate 70.
A low friction guide ring 91, conveniently made from NYLATRON or TEFLON material, a low friction seal 92 made from similar material, a seal spacer 93 and a retaining ring 94 are mounted about the stem 61 on opposite sides of the diaphragm 75 and diaphragm plates 52, 53 as illustrated. The objective is to minimize or eliminate metal-to-m~tal contact occurring during movement of the stem 61.
A set screw 71 is threadedly engaged into a - complementary threaded connection in the bottom of stem 61. Set screw 71 may he adjusted upwardly and downwardly with respect to stem 61 for adjustment purposes as will be explained hereafter. An O-ring 72 is positioned about stem 61 between stem 61 and valve side diaphragm plate 53.
Diaphragm 75 is mounted between the spring side diaphragm plate 52 and the valve side diaphragm plate 531 the spring and valve side diaphragm plates 52, 53r respectively, providing support for the diaphragm 75. The diaphragm 75 has a diameter that extends beyond the outside diameter of the diaphra~m plates 52~ 53 and into the area directly between the spring and valve side flanges 34, 40, respectively. Both the high pressure side of the diaphragm 75 and the low pressure side of the diaphragm 75 are of 2 ~
the same area. Accordingly, the force differential created by the difference in force between the two sides of the diaphragm 75 created by the pressure difference between the pressure differential between upstream and downstream flanges 13, 14, respectively, tends to move diaphragm 75 upwardly as viewed in Figure 2 and this force is counteracted by spring 64. A ball 80 acts downwardly on spring plate 70. A spring screw 81 acts on ball 80 and is adjustably and threadedly engaged in plug 82 so as to adjust the position of the diaphragm 75 as will be set out hereafter. Plug 82 is threadedly en~agsd with the spring hsusing 42 in the top of spring housing 42. An O-ring sealed plug 83 acts as a weather seal to prevent the ingress of foreign matter into the assembly 31.
A pilot valve subassembly (not shown) is threadedly engaged with valve side adapter 44. The pilot valve subassembly is used to initiate the operation of a safety valve (not shown) to terminate flow in the flow line 10. Its operation i5 initiated by the actisn of the differential pressure sensor assembly 31 acting on a plunger 90 which is operably connected with the pilot valve assembly. The construction of the pilot valve assembly is not germane to the operation of the differential pressure sensor assembly 31 and, therefore, its construction will not be described.
The plunger 90 of the pilot valve assembly is oparated by the movement of the set screw 7~ with the vertical movement of stem 61. That is, as the stem 61 moves upwardly as will be described in greater detail, set screw 71 will likewise move. This initiates the operation of the pilot valve assembly through plunger 90 which, in turn, will terminate flow in the pipeline lOo .
2 ~
OPERATION
To assemble the differential pressure sensor assembly 31, spring side diaphragm plate 52, diaphragm 75 and valve side diaphragm plate 53 are positioned on stem 61 together with O-ring 72 of valve side diaphragm plate 53. A shoulder 54 and a nut 60 serve to retain the assembly as illustrated in Figure 2~ The valve side flange 40 and the spring side ~lange 34 are then assembled and loosely connected with cap screws 41. The spring housing 42 and the spring side flange 34 are moved downwardly until the valve side diaphragm plate 53 bottoms on the cavity within valve side flange 40. This results in the diaphragm 75 being deflected downwardly and thereby ensuring it is not in contact with the O-ring 51. Cap s~rews 41 are then tightened until the valve side flange 40 fully contacts the spring side flange 34 and O-ring 51 is compressed between the spring and valve side flanges 34, 40, rPspectively.
Under normal flow conditions in flow line 10, the pressure di~ferential between the upstream flange 13 .: and, accordingly, upstream port 22 and downstream flange 14 and, accordingly, downstream port 23, is known.
Likewise, the pressure conditions in the flow line 10 are known. Thus, the differential pressure assembly 31 is designed to provide a '~neutral" position for the diaphragm 75 between spring and valve side diaphra~n plates 52, 53, respectiYely, under such normal conditions as illustrated - 30 and the force in spring 64 may be adjusted by spring screw 81 so as to maintain the diaphragm 75 in such a position~
The position of set screw 71 within stem 61 may also be adjusted so that spring biased plunger 90 of the pilot valve assembly assumes its correct and untriggered position under the normal operating conditions.
An increase in flow rate caused by leakage in the flow line 12 initiates operational movement of the stem 61~ When the pressure acting on the diaphragm 75 increases if, for example, the flow is increased due to a leak in the flow line 12, the stem 61 will move upwardly against spring 64 under the influence of diaphragm 75 and spring side diaphragm plate 52 which provides support for the diaphragm 75 which would otherwise not be capable of resisting the force created by the pressure differential between its two opposite sides.
When the diaphragm 75 is fully moved upwardly against diaphragm plate 52 and diaphragm plate 52 has I'bottomed'~ in the cavity between tha valve and spring side flanges 34, 40 and is abutting spring side flange 34, the only area of diaphragm 75 that is not supported by the spring side diaphragm plate 52 or spring side flange 34 is that area adjacent the bevelled portion 55 of diaphragm plate 52 and that bevelled or cavity area 56 of spring side flange 34. Thus, the force that may be utilised against diaphragm 75 by the pressure differential is increased significantly b~cause of the enhanced ability of the diaphragm 75 to resist the force created by the pressure differential. Upon upwards movement of stem 61 with diaphragm 75, spring biased plunger 90 will likewise move upwardly in contact with set screw 71. The operat}on of the pilot valve will thereby be initiated to terminate pipeline flow.
When the ~low line 10 is returned to its normal operating condition, the differential pressure assembly 31 will automatically return to its neutral operating position.
The dif~erential pressure sensor assembly according to the present invention is typically used with 2 ~
a flow line having a 2-4l' nominal size and which carries a gas under pressure at approximately 2000 p.soi. A
change in pressure differential of 3-12 p.s.i. acxoss the flow measuring orifice will result in appropriate operation of the differential pressure sensor assembly 31 and is sensed thereby.
Many modifications will readily occur to those skilled i~ the art to which the invention relates and the specific embodiment described should be considered as illustrative of the invention only and not as limiting its - scope as defined in accordance with the accompanying claims.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A differential pressure sensor assembly comprising a stem, a diaphragm mounted on said stem, first and second diaphragm plates mounted on said stem with said diaphragm being positioned between said diaphragm plates, at least one of said diaphragm plates providing support for said diaphragm across a substantial portion of its area, spring means acting on said stem, said diaphragm being exposed to high and low pressures on opposite sides of said diaphragm, said stem being movable with said diaphragm and said diaphragm plates upon a predetermined change in said pressure differential between opposite sides of said diaphragm.
2. A differential pressure sensor assembly as in claim 1 wherein the area of said opposite sides of said diaphragm are equal.
3. A differential pressure sensor assembly as in claim 2 wherein said first and second diaphragm plates and said diaphragm are maintained in position on said stem.
4. A differential pressure sensor assembly as in claim 3 wherein said first diaphragm plate is a spring side diaphragm plate located on the same side of said diaphragm as said spring and said second diaphragm plate is a valve side diaphragm plate located on the opposite side of said diaphragm.
5. A differential pressure sensor assembly as in claim 4 wherein said diaphragm plates form a bevelled cavity about their peripheries, said diaphragm being supported across its area by at least one of said diaphragm plates except for said area adjacent said bevelled cavity of said diaphragm plates.
6. A differential pressure sensor assembly as in claim 5 and further including a high pressure port acting on the same side of said diaphragm as said valve side diaphragm plate.
7. A differential pressure sensor assembly as in claim 6 and further including a low pressure port acting on the same side of said diaphragm as said spring side diaphragm plate.
8. A differential pressure sensor assembly as in claim 7 wherein said spring means is adjustable to vary the force acting on said stem and said diaphragm by said spring means.
9. A differential pressure sensor assembly as in claim 8 wherein said stem further includes a adjustor screw movable within said stem on the same side of said stem as said valve side diaphragm plate, said adjustor screw being operable to contact and control a plunger of a pilot valve assembly, said pilot valve assembly being operably mounted to and controlled by said differential pressure sensor assembly.
10. A differential pressure sensor assembly as in claim 9 wherein the pressure differential between said high and low pressure ports is created by a flow restricting orifice.
11. A differential pressure sensor assembly as in claim 10 wherein said flow restricting orifice includes a wedge restriction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002050418A CA2050418A1 (en) | 1991-08-30 | 1991-08-30 | Differential pressure sensing pilot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002050418A CA2050418A1 (en) | 1991-08-30 | 1991-08-30 | Differential pressure sensing pilot |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050418A1 true CA2050418A1 (en) | 1993-03-01 |
Family
ID=4148283
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002050418A Abandoned CA2050418A1 (en) | 1991-08-30 | 1991-08-30 | Differential pressure sensing pilot |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2050418A1 (en) |
-
1991
- 1991-08-30 CA CA002050418A patent/CA2050418A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19940228 |