CA1056256A - Anti-oscillating diaphragm construction - Google Patents
Anti-oscillating diaphragm constructionInfo
- Publication number
- CA1056256A CA1056256A CA266,836A CA266836A CA1056256A CA 1056256 A CA1056256 A CA 1056256A CA 266836 A CA266836 A CA 266836A CA 1056256 A CA1056256 A CA 1056256A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- diaphragm
- seat
- outlet
- valve portion
- 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.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
A diaphragm valve construction for use with servo-regulated valves which substantially eliminates the problem of outlet pressure oscillation under low-flow high inlet pressure conditions. Briefly, the main diaphragm valve is constructed so that a larger effective area is provided on one side of the main valve seat than on the other, resulting in a hinging effect on the valve as it closes and opens. Under critical low-flow high inlet pressure conditions, one side of the main valve actually remains on the valve seat while the other side is lifted away from the seat to permit flow through the valve.
A diaphragm valve construction for use with servo-regulated valves which substantially eliminates the problem of outlet pressure oscillation under low-flow high inlet pressure conditions. Briefly, the main diaphragm valve is constructed so that a larger effective area is provided on one side of the main valve seat than on the other, resulting in a hinging effect on the valve as it closes and opens. Under critical low-flow high inlet pressure conditions, one side of the main valve actually remains on the valve seat while the other side is lifted away from the seat to permit flow through the valve.
Description
1056Z~6 :: .
Prior art servo-regulated type valves have operated satisfactorily for their intended purpose in the past. However, one detrimental characteristic has tended to prevent their use under certain conditions or for certain appli-cations. Specifically, while it is desired that these valves regulate outlet pressure for a wide range of inlet pressure and flow conditions, it has not yet been able to attain stable outlet pressure regulation under low-flow high ; ~ inlet pressure conditions. Prior to the present invention, under low-flow$
high inlet pressure conditions, the outlet pressure of servo regulated type valves has severely oscillated about the desired pressure. This oscillating 10 condition of the outlet pressure has sometimes been known aR "hunting". This ` ~ severe oscillation in outlet pressure results because the main diaphragm valve rapidly closes and opens. It is believed that this oscillation occursbe-.
cause the diaphragm valve is in close proximity to its seat under high inlet pressure low flow conditions. As gas flows past the seat, the velocity of the gas traveling across it tends to create a sucking for ce which pulls the main diaphragm valve closed. This sudden closing engagement decreases .
-~ the outlet pressure below the desired level and the resultant fluid feedback signal from the outlet passageway then forces the valve face a disproportion-age distance away from the valve seat. This continued oscillation of the out-20 let pres8ure level cannot be tolerated.
,~ In order to minimize this oscillating problem, the diaphragm structure of U. S. Patent No. 3, 468, 511 was developed. With the diaphragm structure shown in this patent, at low flow conditions, a portion of the valve is seated against the seat and the flow occurs past another portion of the valve.
U. S. Patent No. 2, 746, 471 discloses a combination regulator and shut-` off valve in which the shut-off valve seat is not located concentrically with respect to the valve. With this arrangement, one side of the valve unseats itself before the other side, thus resulting in a tilting or hinged effect on the diaphragm.
. . - 1,-Accordingly, it is an object of the present invention to overcome the .:"
undesirable oscillating tendency in servo-regulated type valves so as to ex-tend their range of pressure regulation even to high-inlet pressure low flow conditions .
It is another object of the present invention to provide a simple, reli-able diaphragm valve construction which substantially eliminates the undesirable oscillating tendency in servo regulated type valves.
An additional object of the invention is to provide a diaphragm valve ~i construction which substantially eliminates the oscillating tendency at high inlet pressure low flow conditions in servo regulated type valves and which -is adaptable to existing designs with a minimum amount of tooling changes.
In accordance with the present invenffon, the main diaphragm valve for a servo regulated type valve is caused to unseat and seat itself in a tilting manner whereby one side of the valve remains seated while the other side of the valve is open. It has been found that this construction substantially elim-inates the tendency for such valves to oscillate. Preferably, this tilffng motion of the main diaphragm valve upon opening and closing is accomplished ecce~ ,7 C~ Y~ CC/~
by~ lly locating the main valve seat with respect to the dia-phragm so as to unbalance the effective area of the diaphragm surrounding the valve seat. This results in a larger force acting on the one side of the valve to open it first.
In the course of the detailed description of the invenffon, reference will be made to the drawings in which:
FIG. 1 is a diagrammatic view of a servo regulated gas valve having a main diaphragm valve construcffon in accordance with the present invention;
FIG. 2 is a cross sectional view of a portion of a combination gas valve in which the main seat structure has been modified in accordance with the present invention;
FIG. 3 is a view similar to FIG. 2 except that the main diaphragm valve of the invention is shown in its position under high inlet pressure, low-flow conditions; ~
.: ~
:. 1056Z56 FIG. 4 is a view similar to FIG. 3 except that the main diaphragm valve t j of the invention is shown in its completely open position; and FIG. 5 is a reproduction of a graph taken from an x-y plotter showing the relationship of outlet pressure to inlet pressure for conventional servo regulated valve and the same type valve utilizing a diaphragm valve in ac-cordance with the present invention.
Referring to FiG. 1, a servo regulated valve incorporating a main dia-- phragm valve in accordance with the present invention is shown. The construction and operation of the components of this valve are well known 10 with the exception of the location, construction and operation of the main diaphragm valve which for~ls part of the present invention. Therefore, the various components of this servo regulated valve will not be described in detail except where required to understand the invention.
The servo regulated gas valve generally indicated by reference num-eral 10 includes internally threaded inlet and outlet connections indicated by reference numerals 12 and 14 respectively. The valve 10 also has another internaUy threaded connection 15 through which gas is supplied to a pilot.
Gas flows from inlet lZ into a safety chamber 16 in which a resettable safety valve assembly is situated. The safety valve assembly includes a 20 valve actuator 18 which is attracted to an electromagnet 20, and safety valve 22 attached to lever 24. A compression spring member 26 biases safety valve actuator 18 toward the off position and a lever member 28 is used to re-set the safety valve assembly. Pivoted lever 24 is biased toward the open ,., position by a leaf spring member 30.
Safety valve 22 controls the flow of gas from safety chamber 16 into a redundant chamber 32 having a redundant electromagnetic valve operator - ¦ 34 situated therein. Redundant valve operator 34 attracts armature mem-ber 36, to which valve member 38 is attached, and is biased to the closed position by spring member 30, so as to control flow between redundant ; .~ O ~ ~iZ 5 6 . ., chambers 32 and chamber 42. Chamber 42 is seapated from a control chamber 44 by a round diaphragm member 46 having a circular thickened portion 48 which acts in cooperation with valve seat 50 to control flow from chamber 42 to a plug valve 54 and ultimately to the outlet 14. A plate member 56 is attached to the underside of diaphragm 46 and a compression spring member 58 situated between the plate 56 and a portion of the housing biases valve 48 toward the closed position.
It will be noticed from the drawings that valve member 48 is formed integrally with diaphragm 46 and is located eccentrically thereon such that the center of portion 48 is spaced from the center of diaphragm 46. By locating the valve portion 48 eccentrically (i.e. non-concentrically) with diaphragm 46, the diaphragm area surrounding valve portion 48 becomes unbalanced. This results in greater opening forces acting on diaphragm 46 on one side of valve portion 48 than on the other side due to the pressure in chamber 42. Consequently, valve portion 48 tends to tilt . . .
.` off its seat 50 as it opens. This tilting has been observed to substantially reduce the previously mentioned oscillation problem.
. ., Referring still to FIG. l, manually rotatable plug valve 54 controls flow from the output of valve portion 48 to outlet 14 as was previously mentioned, controls flow from redundant chamber 32 to filter 60 and ultimately to pilot outlet 15, and additionally controls flow from passage-way 62 to another passageway 64. Passageway 62 leads from a bleed chamber 66 in which a bleed valve operator 68 is located. Electromagnetic bleed valve operator 68 attracts armature member 70 which has a valve portion 72 and which is biased to the closed position by leaf spring 74. Bleed chamber is connected to chamber 42 through a passageway 76 ~ .
.
iZ56 filter member 78 and restriction 80. Additionally, bleed - chamber 66 is connected to control chamber 44 by a passage- ;
way 82.
: Passageway 64 leads to the input of a servo regulator 84, the output ~-'' :
' ., :, .
:
~ .
..' ., :
:. ,~
;'`,.
!, ~, ` ..
~,:
-4a- ::
` 1056256 ;~ of which is connected to outlet 14 via a restricted passageway 86. The ' ~ construction of servo regulator 84 is conventional and will therefore only be described briefly. Servo regulator 84 includes a diaphragm member 86 having a valve member 88 attached thereto and biased to the open position by spring 90. Diaphragm member 86 separates a chamber 92 connected to the atmosphere from a chamber 94.
A knob member 96 serves the dual function of rotating plug valve 54 when rotated and resetting the safety valve when depressed. Knob 96 is ~ biased outwardly by compression spring 98 and urges pin member 100 10 downwardly when depressed against lever member 28 to reset the safety ' valve assembly.
~ The operation of the diaphragm assembly of the present invention will .:, .
now be described in conjunction with the servo-regulated valve FIG. 1.
Assuming first of all that safety valve 22 and plug valve 54 are both open, . . .
when bleed valve operator 68 and redundant valve operator 34 are energi-zed, as a result of the thermostat contacts closing, gas will be bled off ., from chamber 44 through 82, 66, 62, 64, servo regulator 84 and 86 to the outlet 14 at a rate higher than can be supplied to chamber 66 through re- q ~:
:. striction 80. This results in a pressure differential across diaphragm 46, 20 causing it to slowly move toward the open position. In prior art valves, . under high inlet pressure, low-flow-conditions, the valve would be sucked closed by the velocity of the flow past seat 50 and would oscillate between . .
open and closed positions. However, with the diaphragm construction of the invention, the right side of valve portion 48 (as viewed in FIG. 1) lifts away from seat 50 first because of a greater downward force created by the pressure in chamber 42 acting on the larger right hand side of diaphgram 46. Depending on the flow conditions, a portion of valve portion 48 may remain on seat 50 or may be completely disengaged therefrom. The rea-son that the tilting movement of valve portion 48 substantially eliminates .
``- 1056256 ,`':;' 1 the oscillation problem is not entirely understood, but it is believed that the sucking force created by the velocity of the flow past seat 50 has a much greater effect on conventional diaphragm valve designs because of the proximity to its seat. With the tilted valve construction of the invention, however, the area of valve portion 48 in close proximity to seat when tilted is greatly reduced.
FIGS. 2-4 serve to illustrate the tilting movement of a main diaphragm ` valve of a servo regulated valve in accordance with the present invention and also serve to illustrate how existing tooling can be modified to take ad-10 vantage of the present invention. In these drawing FIGURES only the main diaphragm valve and seat are shown, and it will be assumed that the com-bination valve in which these are included has conventional bleed and servo-regulating controls similar to those disclosed in FIG. 1.
Referring to FIG.2, a lower portion of 102 the housing for the valve includes an inlet connection 104, an outlet connection 106 and a valve seat 108. An upper housing section 110 has a circular flange 112 which mates with a circular diaphragm member 116 therebetween. Flange sections 112 and 114 are held together by suitable means such as cap screws or the like.
¦ Diaphragm member 116 is symmetrical about any imaginary plane passing 20 through any diameter and includes a thickened central valve portion 118, a dish shaped plate member 120 attached to the upper side and a spring re-taining member 122 on top of plate member 120. Spring retaining member 122 serves to retain compression spring 124, located between a lower wall of housing section 110 and retainer member 12Z in place. Dashed line 126 indicates the center of circular diaphragm 116.
`i Dashed line lZ8 indicates the center of circular valve seat 108. It will be seen, therefore, that valve seat 108 is essentially offset from the center of diaphragm 116 creating a larger area on one side of the underside of diaphragm 116. This larger area creates a greater~upward force on the . . , , ' left side of diaphragm 116 than on the right side of diaphragm 116 due to in-let pressure. This results in the tilting movement as described in connec-tion with FIG. 1.
In FG. 2 valve portion 118 contacts seat 108 to completely prevent flow from inlet 104 to outlet 106. In FIG. 3 diaphragm 116 and valve portion 118 are shown in the position which they assume under high inlet pressure low flow conditions. Under these conditions the left side of valve portion tilts away from seat 108 while the right side of valve portion 118 remains seated . ,, on seat 108. In FIG. 4 diaphragm 116 and valve portion 118 are shown in 10 the position which they assume under high inlet pressure, high flow condi-, . .
-~ tions. Under these conditions valve portion 118 assumes a position ~' completely removed from valve seat 108.
;' With conventional servo-regulated controls the main valve seat is lo-~ cated concentrically with the diaphragm. Existing tooling for such devices ".
-; can be modified easily to take advantage of the present invention. In most cases the tooling for ~he lower housing portion need only be modified so as ,-~
to offset the main seat only a slight distance from the center of the diaph-. . .
ragm.
FIG. 5 illustrateæ graphically how the present invention eliminates the main valve oscillation problem. In the upper graph, outlet pressure is plot-ted vs. inlet pressure for a conventional concentric seat servo regulated type valve. The graphs were taken from an XY plotter and the flow rate was 186 CFH. It will be seen from the graph that the outlet pressure re-mained at a substantially constant level when the inlet pressure was in the range of 13-17. 5 inches water column. However, when the inlet pressure was greater than 17. 5 inches water column, the outlet pressure for the conventional valve severely varies between the unacceptable range of 2. 5-6. 5 inches water column. In contrast, however, the date for the lower graph of FIG. 5 was taken at the same flow rate from a servo-regulated lOS6i2S6 ,.. 1 ~1 valve of the same model as that of the upper graph with the exception that ¦
the main seat was offset slightly from the center of the diaphragm. It will - - be seen from the lower graph in FIG. 5 that the servo regulated valve, modi-fied in accordance with the present invention, provided substantially constant outlet pressure whenever the inlet pressure varied from 13 to 22 :
inches water column, thus effectively extending the useful range of the ,. valve.
:.
It is intended that the above detailed description of the inventiOn be , used for exemplary purposes only and is not intended to limit the invention.
10 The scope of the invention is defined in the claims.
,. . .
: !
'''' ' ' :.
. , .. 1 .
,,, ~
. ,- , :, .
:
Prior art servo-regulated type valves have operated satisfactorily for their intended purpose in the past. However, one detrimental characteristic has tended to prevent their use under certain conditions or for certain appli-cations. Specifically, while it is desired that these valves regulate outlet pressure for a wide range of inlet pressure and flow conditions, it has not yet been able to attain stable outlet pressure regulation under low-flow high ; ~ inlet pressure conditions. Prior to the present invention, under low-flow$
high inlet pressure conditions, the outlet pressure of servo regulated type valves has severely oscillated about the desired pressure. This oscillating 10 condition of the outlet pressure has sometimes been known aR "hunting". This ` ~ severe oscillation in outlet pressure results because the main diaphragm valve rapidly closes and opens. It is believed that this oscillation occursbe-.
cause the diaphragm valve is in close proximity to its seat under high inlet pressure low flow conditions. As gas flows past the seat, the velocity of the gas traveling across it tends to create a sucking for ce which pulls the main diaphragm valve closed. This sudden closing engagement decreases .
-~ the outlet pressure below the desired level and the resultant fluid feedback signal from the outlet passageway then forces the valve face a disproportion-age distance away from the valve seat. This continued oscillation of the out-20 let pres8ure level cannot be tolerated.
,~ In order to minimize this oscillating problem, the diaphragm structure of U. S. Patent No. 3, 468, 511 was developed. With the diaphragm structure shown in this patent, at low flow conditions, a portion of the valve is seated against the seat and the flow occurs past another portion of the valve.
U. S. Patent No. 2, 746, 471 discloses a combination regulator and shut-` off valve in which the shut-off valve seat is not located concentrically with respect to the valve. With this arrangement, one side of the valve unseats itself before the other side, thus resulting in a tilting or hinged effect on the diaphragm.
. . - 1,-Accordingly, it is an object of the present invention to overcome the .:"
undesirable oscillating tendency in servo-regulated type valves so as to ex-tend their range of pressure regulation even to high-inlet pressure low flow conditions .
It is another object of the present invention to provide a simple, reli-able diaphragm valve construction which substantially eliminates the undesirable oscillating tendency in servo regulated type valves.
An additional object of the invention is to provide a diaphragm valve ~i construction which substantially eliminates the oscillating tendency at high inlet pressure low flow conditions in servo regulated type valves and which -is adaptable to existing designs with a minimum amount of tooling changes.
In accordance with the present invenffon, the main diaphragm valve for a servo regulated type valve is caused to unseat and seat itself in a tilting manner whereby one side of the valve remains seated while the other side of the valve is open. It has been found that this construction substantially elim-inates the tendency for such valves to oscillate. Preferably, this tilffng motion of the main diaphragm valve upon opening and closing is accomplished ecce~ ,7 C~ Y~ CC/~
by~ lly locating the main valve seat with respect to the dia-phragm so as to unbalance the effective area of the diaphragm surrounding the valve seat. This results in a larger force acting on the one side of the valve to open it first.
In the course of the detailed description of the invenffon, reference will be made to the drawings in which:
FIG. 1 is a diagrammatic view of a servo regulated gas valve having a main diaphragm valve construcffon in accordance with the present invention;
FIG. 2 is a cross sectional view of a portion of a combination gas valve in which the main seat structure has been modified in accordance with the present invention;
FIG. 3 is a view similar to FIG. 2 except that the main diaphragm valve of the invention is shown in its position under high inlet pressure, low-flow conditions; ~
.: ~
:. 1056Z56 FIG. 4 is a view similar to FIG. 3 except that the main diaphragm valve t j of the invention is shown in its completely open position; and FIG. 5 is a reproduction of a graph taken from an x-y plotter showing the relationship of outlet pressure to inlet pressure for conventional servo regulated valve and the same type valve utilizing a diaphragm valve in ac-cordance with the present invention.
Referring to FiG. 1, a servo regulated valve incorporating a main dia-- phragm valve in accordance with the present invention is shown. The construction and operation of the components of this valve are well known 10 with the exception of the location, construction and operation of the main diaphragm valve which for~ls part of the present invention. Therefore, the various components of this servo regulated valve will not be described in detail except where required to understand the invention.
The servo regulated gas valve generally indicated by reference num-eral 10 includes internally threaded inlet and outlet connections indicated by reference numerals 12 and 14 respectively. The valve 10 also has another internaUy threaded connection 15 through which gas is supplied to a pilot.
Gas flows from inlet lZ into a safety chamber 16 in which a resettable safety valve assembly is situated. The safety valve assembly includes a 20 valve actuator 18 which is attracted to an electromagnet 20, and safety valve 22 attached to lever 24. A compression spring member 26 biases safety valve actuator 18 toward the off position and a lever member 28 is used to re-set the safety valve assembly. Pivoted lever 24 is biased toward the open ,., position by a leaf spring member 30.
Safety valve 22 controls the flow of gas from safety chamber 16 into a redundant chamber 32 having a redundant electromagnetic valve operator - ¦ 34 situated therein. Redundant valve operator 34 attracts armature mem-ber 36, to which valve member 38 is attached, and is biased to the closed position by spring member 30, so as to control flow between redundant ; .~ O ~ ~iZ 5 6 . ., chambers 32 and chamber 42. Chamber 42 is seapated from a control chamber 44 by a round diaphragm member 46 having a circular thickened portion 48 which acts in cooperation with valve seat 50 to control flow from chamber 42 to a plug valve 54 and ultimately to the outlet 14. A plate member 56 is attached to the underside of diaphragm 46 and a compression spring member 58 situated between the plate 56 and a portion of the housing biases valve 48 toward the closed position.
It will be noticed from the drawings that valve member 48 is formed integrally with diaphragm 46 and is located eccentrically thereon such that the center of portion 48 is spaced from the center of diaphragm 46. By locating the valve portion 48 eccentrically (i.e. non-concentrically) with diaphragm 46, the diaphragm area surrounding valve portion 48 becomes unbalanced. This results in greater opening forces acting on diaphragm 46 on one side of valve portion 48 than on the other side due to the pressure in chamber 42. Consequently, valve portion 48 tends to tilt . . .
.` off its seat 50 as it opens. This tilting has been observed to substantially reduce the previously mentioned oscillation problem.
. ., Referring still to FIG. l, manually rotatable plug valve 54 controls flow from the output of valve portion 48 to outlet 14 as was previously mentioned, controls flow from redundant chamber 32 to filter 60 and ultimately to pilot outlet 15, and additionally controls flow from passage-way 62 to another passageway 64. Passageway 62 leads from a bleed chamber 66 in which a bleed valve operator 68 is located. Electromagnetic bleed valve operator 68 attracts armature member 70 which has a valve portion 72 and which is biased to the closed position by leaf spring 74. Bleed chamber is connected to chamber 42 through a passageway 76 ~ .
.
iZ56 filter member 78 and restriction 80. Additionally, bleed - chamber 66 is connected to control chamber 44 by a passage- ;
way 82.
: Passageway 64 leads to the input of a servo regulator 84, the output ~-'' :
' ., :, .
:
~ .
..' ., :
:. ,~
;'`,.
!, ~, ` ..
~,:
-4a- ::
` 1056256 ;~ of which is connected to outlet 14 via a restricted passageway 86. The ' ~ construction of servo regulator 84 is conventional and will therefore only be described briefly. Servo regulator 84 includes a diaphragm member 86 having a valve member 88 attached thereto and biased to the open position by spring 90. Diaphragm member 86 separates a chamber 92 connected to the atmosphere from a chamber 94.
A knob member 96 serves the dual function of rotating plug valve 54 when rotated and resetting the safety valve when depressed. Knob 96 is ~ biased outwardly by compression spring 98 and urges pin member 100 10 downwardly when depressed against lever member 28 to reset the safety ' valve assembly.
~ The operation of the diaphragm assembly of the present invention will .:, .
now be described in conjunction with the servo-regulated valve FIG. 1.
Assuming first of all that safety valve 22 and plug valve 54 are both open, . . .
when bleed valve operator 68 and redundant valve operator 34 are energi-zed, as a result of the thermostat contacts closing, gas will be bled off ., from chamber 44 through 82, 66, 62, 64, servo regulator 84 and 86 to the outlet 14 at a rate higher than can be supplied to chamber 66 through re- q ~:
:. striction 80. This results in a pressure differential across diaphragm 46, 20 causing it to slowly move toward the open position. In prior art valves, . under high inlet pressure, low-flow-conditions, the valve would be sucked closed by the velocity of the flow past seat 50 and would oscillate between . .
open and closed positions. However, with the diaphragm construction of the invention, the right side of valve portion 48 (as viewed in FIG. 1) lifts away from seat 50 first because of a greater downward force created by the pressure in chamber 42 acting on the larger right hand side of diaphgram 46. Depending on the flow conditions, a portion of valve portion 48 may remain on seat 50 or may be completely disengaged therefrom. The rea-son that the tilting movement of valve portion 48 substantially eliminates .
``- 1056256 ,`':;' 1 the oscillation problem is not entirely understood, but it is believed that the sucking force created by the velocity of the flow past seat 50 has a much greater effect on conventional diaphragm valve designs because of the proximity to its seat. With the tilted valve construction of the invention, however, the area of valve portion 48 in close proximity to seat when tilted is greatly reduced.
FIGS. 2-4 serve to illustrate the tilting movement of a main diaphragm ` valve of a servo regulated valve in accordance with the present invention and also serve to illustrate how existing tooling can be modified to take ad-10 vantage of the present invention. In these drawing FIGURES only the main diaphragm valve and seat are shown, and it will be assumed that the com-bination valve in which these are included has conventional bleed and servo-regulating controls similar to those disclosed in FIG. 1.
Referring to FIG.2, a lower portion of 102 the housing for the valve includes an inlet connection 104, an outlet connection 106 and a valve seat 108. An upper housing section 110 has a circular flange 112 which mates with a circular diaphragm member 116 therebetween. Flange sections 112 and 114 are held together by suitable means such as cap screws or the like.
¦ Diaphragm member 116 is symmetrical about any imaginary plane passing 20 through any diameter and includes a thickened central valve portion 118, a dish shaped plate member 120 attached to the upper side and a spring re-taining member 122 on top of plate member 120. Spring retaining member 122 serves to retain compression spring 124, located between a lower wall of housing section 110 and retainer member 12Z in place. Dashed line 126 indicates the center of circular diaphragm 116.
`i Dashed line lZ8 indicates the center of circular valve seat 108. It will be seen, therefore, that valve seat 108 is essentially offset from the center of diaphragm 116 creating a larger area on one side of the underside of diaphragm 116. This larger area creates a greater~upward force on the . . , , ' left side of diaphragm 116 than on the right side of diaphragm 116 due to in-let pressure. This results in the tilting movement as described in connec-tion with FIG. 1.
In FG. 2 valve portion 118 contacts seat 108 to completely prevent flow from inlet 104 to outlet 106. In FIG. 3 diaphragm 116 and valve portion 118 are shown in the position which they assume under high inlet pressure low flow conditions. Under these conditions the left side of valve portion tilts away from seat 108 while the right side of valve portion 118 remains seated . ,, on seat 108. In FIG. 4 diaphragm 116 and valve portion 118 are shown in 10 the position which they assume under high inlet pressure, high flow condi-, . .
-~ tions. Under these conditions valve portion 118 assumes a position ~' completely removed from valve seat 108.
;' With conventional servo-regulated controls the main valve seat is lo-~ cated concentrically with the diaphragm. Existing tooling for such devices ".
-; can be modified easily to take advantage of the present invention. In most cases the tooling for ~he lower housing portion need only be modified so as ,-~
to offset the main seat only a slight distance from the center of the diaph-. . .
ragm.
FIG. 5 illustrateæ graphically how the present invention eliminates the main valve oscillation problem. In the upper graph, outlet pressure is plot-ted vs. inlet pressure for a conventional concentric seat servo regulated type valve. The graphs were taken from an XY plotter and the flow rate was 186 CFH. It will be seen from the graph that the outlet pressure re-mained at a substantially constant level when the inlet pressure was in the range of 13-17. 5 inches water column. However, when the inlet pressure was greater than 17. 5 inches water column, the outlet pressure for the conventional valve severely varies between the unacceptable range of 2. 5-6. 5 inches water column. In contrast, however, the date for the lower graph of FIG. 5 was taken at the same flow rate from a servo-regulated lOS6i2S6 ,.. 1 ~1 valve of the same model as that of the upper graph with the exception that ¦
the main seat was offset slightly from the center of the diaphragm. It will - - be seen from the lower graph in FIG. 5 that the servo regulated valve, modi-fied in accordance with the present invention, provided substantially constant outlet pressure whenever the inlet pressure varied from 13 to 22 :
inches water column, thus effectively extending the useful range of the ,. valve.
:.
It is intended that the above detailed description of the inventiOn be , used for exemplary purposes only and is not intended to limit the invention.
10 The scope of the invention is defined in the claims.
,. . .
: !
'''' ' ' :.
. , .. 1 .
,,, ~
. ,- , :, .
:
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a servo-regulated valve having a housing with an inlet and outlet, circular diaphragm means separating a portion of said housing into first and second chambers, a main valve seat located in the flow path between said inlet and outlet, a central portion of said diaphragm means being thicker than the periphery thereof so as to form a valve portion which cooperates with said main valve seat to control flow between said inlet and said out-let, means creating a pressure differential between said chambers for moving said diaphragm so as to move said valve portion toward and away from said main valve seat, means for biasing said valve portion toward the closed position, servo regulator means connected between one of said chambers and said outlet for causing the pres-sure at said outlet to remain substantially constant, the improve-ment wherein said main valve seat is located eccentrically with respect to said circular diaphragm to substantially reduce oscillation of said valve portion under high inlet pressure, low flow conditions.
2. The improvement as claimed in Claim 1 wherein said valve portion is located eccentrically with respect to said dia-phragm and concentrically with said main valve seat.
3. The improvement as claimed in Claim 1 wherein said valve portion is located concentric with said diaphragm.
4. The improvement as claimed in Claim 1 wherein said valve portion comprises the entire thickened central portion of said diaphragm.
5. The improvement as claimed in Claim 2 wherein said valve portion comprises the entire thickened central portion of said diaphragm.
6. The improvement as claimed in Claim 3 wherein the axis of said valve portion lies within said valve seat.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65832276A | 1976-02-17 | 1976-02-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056256A true CA1056256A (en) | 1979-06-12 |
Family
ID=24640769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,836A Expired CA1056256A (en) | 1976-02-17 | 1976-11-29 | Anti-oscillating diaphragm construction |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1056256A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4625695A (en) * | 1985-03-28 | 1986-12-02 | Walbro Corporation | Fuel pressure regulator |
| US10817002B2 (en) | 2017-06-20 | 2020-10-27 | Honeywell Technologies Sarl | Gas valve and gas control device |
-
1976
- 1976-11-29 CA CA266,836A patent/CA1056256A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4625695A (en) * | 1985-03-28 | 1986-12-02 | Walbro Corporation | Fuel pressure regulator |
| US10817002B2 (en) | 2017-06-20 | 2020-10-27 | Honeywell Technologies Sarl | Gas valve and gas control device |
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