US 3721263 A
Description (OCR text may contain errors)
Mmh2o,1973 QUWSOS mi, y 3,721,263
STEPPED OPENING FLUID PRESSURE OPERATED VALVE Filed NOV. l0. 1971 United States Patent O 3,721,263 STEPPED OPENING FLUID PRESSURE OPERATED VALVE Charles D. Visos, Manchester, and .lohn J. Love and Ralph E. Balles, St. Louis, Mo., assignors to Emerson Electric Co., St. Louis, Mo.
Filed Nov. 10, 1971, Ser. No. 197,438 Int. Cl. F16k 31 /12 U.S. Cl. 137-495 8 Claims ABSTRACT F THE DISCLOSURE A biased closed gas valve controlling a main passageway is moved openward by a rst expansible chamber as it expands. A restricted pressure passageway having a control valve therein connects the chamber with the upstream side of the gas valve and a more highly restricted bleedoff passageway connects the chamber with the downstream side of the gas valve. The pressure in the chamber therefore increases and the gas valve is moved openward when the control valve is opened. A bypass controlled by a biased closed pressure regulator valve permits additional bleed ofIr so as to limit opening of the gas valve to a predetermined partially open position. A second, smaller, expansible chamber having a lost motion operative connection with the pressure regulator operates when it has expanded a predetermined amount to increase the closing bias on the regulator valve, thereby reducing the bleed off through the bypass and causing the gas valve to be fully opened. vA passageway connects the second, smaller, expansible chamber with the first expansible chamber and includes a restricting orifice to delay expansion of the second smaller chamber.
This invention relates to fluid pressure operated gas valves and particularly to means providing stepped opening movement of the valve.
In many installations, it has been found essential to the safe operation of gas burners enclosed in compact combustion chambers to delay the full rated flow of gas to the burner when starting operation thereof until suflicient draft through the combustion chamber has been developed by combustion of a lesser ilow to support the full rated ow.
One method of accomplishing this is to incorporate means which slows the opening of the gas valve sufficiently so that the elapsed time between an initial open position of the valve, which initiates combustion, and the full open position thereof is suicient to permit the necessary draft to develop. However, because the relatively large diameter poppet type valves commonly employed in fluid pressure or diaphragm operated gas valves are required to be moved only a relatively short distance between their closed and full ow open positions, the operation of an arrangement which relys entirely upon a slow rate of valve opening to provide the required delay becomes quite critical.
Another method of operating the valve to accomplish this purpose is to partially open the valve a predetermined amount at a relatively rapid rate to provide only a suicient flow of fuel to the burner to insure good ignition, then interposing a predetermined dwell during which the valve remains in this partial open position, and, then, moving the valve to its full open position either at the same rate or more slowly. This method, commonly called stepped opening, provides assurance that a suflicient initial flow occurs immediately for good ignition and that sufficient delay occurs to develop the required draft through the combustion chamber during the dwell.
An object of this invention is to provide a stepped opening uid pressure operated gas valve in which the ICC valve operating pressure upon starting is regulated at one value thereby to effect a partial initial opening of a biased closed gas valve, is maintained at this value for a predetermined interval, and is then regulated at a higher value thereby to effect full opening of the biased closed valve.
A further object is to provide a stepped opening fluid pressure operated gas valve, as above, in which a biased closed pressure regulator valve controls a bleed off of available valve operating pressure thereby to regulate the valve operating pressure at the one value when starting, in which a Huid pressure responsive actuator responding slowly to regulated valve operating pressure is operative to increase the closing bias of the regulator valve thereby to increase the valve operating pressure to the higher value and effect full opening of the gas valve, and in which a lost motion connection between the actuator and the regulator valve biasing means provides a predetermined delay in the increase of valve operating pressure.
Further objects and advantages will appear from the following complete description when read in connection with the accompanying drawing.
The single figure of the drawing is a cross-sectional view of a manifold gas valve having a stepped opening, diaphragm operated gas valve constructed in accordance with the present invention.
Referring to the drawing, the device comprises a body generally indicated at 10. The body 10 may consist of several sections joined together in any suitable manner to permit casting or boring the cavities and passages therein. In the drawing, the body is illustrated as an integral structure with all passages and cavities lying in the plane of the cross-section, thereby to simplify the description, arrangement, and cooperation of the various elements. The body 10 has an inlet 12 adapted to be connected to a supply of gas under pressure and an outlet 14 connected to a main burner 15. The inlet 12 and outlet 14 are connected by a passageway 16, a chamber 1S, a passageway 20, a hollow rotary plug valve 22, a passageway 24, a chamber 26, and a passageway 2.8.
A safety cutol valve 30 cooperates with the seat to control the flow from the inlet to outlet. The valve 30 is biased closed by a spring 31 and is manually opened by depression of a knob 34 having a pin 36 which engages the valve 30. The valve 30 is held open by an electromagnet 38 energized through leads `41 by a thermocouple junction 40 heated by an adjacent pilot burner 42. This arrangement prevents the flow of fuel to the main burner when the pilot burner is not burning. The hollow rotary plug valve has a main port 44 in the wall thereof which registers with passageway 24 when the plug valve is rotated to an on position. The knob 34 is axially slidable relative to the plug valve 22 on circularly spaced, axially extending tanks 35 which enter circularly spaced sockets 37 in the knob 34. The knob 34 is thereby also keyed to the -plug valve for rotation therewith.
The plug valve 22 is further provided with a circumferentially extending pilot port -46 in the wall thereof which registers with a passageway 48 when the plug valve 22 is in an on position. The pilot outlet S0 is connected to pilot burner 42 by a conduit 51.
A main valve 52 cooperating with an annular seat 54 formed in chamber 26 around the exit of passageway 28 also controls the ow from inlet 12 to outlet 14. Valve 52 has a stem 56 extending downward into an upper diaphragm chamber 58 formed as a recess in body 10, and a spring 59 biases the valve 52 downward in a closed position on its seat 54. A lower diaphragm chamber 60 is formed by a curp-shaped member 62 attached to the body 10, and a flexible diaphragm |64 clamped at its periphery between the body 10 and member 62 defines upper and lower main diaphragm chambers 58 and 60, respectively. The diaphragm 64 includes a relatively rigid disc member 65 centrally positioned and attached thereto. The disc member 65 provides weight to bias the diaphragm downward in the position shown.
The upper diaphragm chamber 58 is adequately vented to outlet passage 28 through a vent 66 so that the upper side of diaphragm 64 is constantly exposed to pressure existing in outlet passage 28. The lower chamber 460 is also in constant communication with outlet passage 28 through a passage 68, a passage 70, a passage 7-1, a restricting Orifice 72, the diaphragm chamber 78 of a pressure regulator generally indicated at 75, and a passage 74. A valve seat 80 controlled lby a pressure regulating valve 82 provides additional venting or bleed off under conditions to be described. The valve 82 forms a part of a pressure regulator diaphragm 83 exposed to atmospheric pressure on its upper side through a vent 85, and a spring 84 biased between a lever 86 and valve 82 biases the valve 82 closed on its seat 80'.
The pressure regulator 75 further comprises a body member 88 suitably attached to the main body member 10, the periphery of regulator diaphragm 83 being clamped between these body members. The lever 186 is pivotally mounted at one end on a pivot pin 90 supported in integrally formed ears 92 depending from a centrally perforated disc 94. The disc 94 is fitted into a bore 96 in the body 88. A second diaphragm chamber 98 is formed in the pressure regulator 75 -by a cup-shaped cover member 100 attached to the upper surface of regulator body 88. A second flexible diaphragm 102 clamped at its periphery between cover member 100 and regulator body 88 forms a pressure movable, wall defining chamber 98. The spring 104 `between the disc 94 and diaphragm 102 biases the diaphragm in an upward position. Diaphragm 102 has an integral, relatively inexible, central portion 106 which forms a seat for spring 104 and supports therein a downwardly extending pin 108 which extends through the central perforation in disc 94. The pin 108 is arranged to engage the lever 86 as it moves downward thereby to increase the -bias `of spring 84, but in its normal biased position shown, there is a predetermined spaced relationship between the lower end of pin 108 and lever 86.
The upper regulator diaphragm chamber 98 communicates with lower main diaphragm cham-ber 60 through passages 68 and 70, a passage 110, a passage 112, and a restricting orice 114, so that a pressure change in chamber 60 is slowly communicated to chamber 98.
Communication between lower main diaphragm chamber 60 and the inlet 12 is also provided through passage 68, a valve seat 116 at the upper end of passage 68, a valve chamber 118, a restricting orice 120, a passage 122, the passage 24, main port 44, the hollow plug valve 22, passage 20, chamber 18, and passage 16. A solenoid operated valve 124, 1biased closed by a spring 126, cooperates with valve seat 116 to control this communication. The valve 124 has a stem 128 connected to the plunger of a solenoid 130. The solenoid has a winding 131 connected across power source terminals 132 through a space thermostat 134. The restricting orice 120 is larger in diameter than restricting orifice 72 in bleed-off line 71, so that when solenoid operated valve 124 is opened, the pressure will increase in diaphragm chamber 60.
OPERATION The manifold valve device is shown in FIG. 1 in an on position; that is to say, the hollow plug valve 22 is in an on position in which gas may ow through its main port y44 to passage 24 and through pilot port 46 to pilot burner 42. Also, the pilot burner is 'burning and cutoff valve 30 is being held open by electromagnet 38. The space thermostat 134 is open, however, so that the solenoid operated control valve 124 is biased closed, whereby communication between inlet 12 and the lower diaphragm chamber -60 is cut off. Since upper main diaphragm chamber 58 is constantly vented to outlet passage 28 through vent 66 and lower main diaphragm chamber 60 is also constantly vented to the same pressure zone through orifice 82, the diaphragm 64 is in its lower position and main valve 52 is biased closed by spring 59.
Under these conditions, when space thermostat 134 closes due to a drop in space temperature, solenoid winding 131 is energized and control valve 124 will open, thereby placing lower diaphragm chamber `60 in cornmunication with inlet 12. The venting orice 72 in passage 71 being smaller than the orifice 120 in passage 122, the pressure in lower main diaphragm chamber 60 now increases, causing the diaphragm 64 to flex upward and move main valve 52 openward a predetermined amount against the biasing spring 59. This partial opening of main valve 52 is determined by the rate of bleed off which occurs past the pressure regulating valve 82, which, in turn, is determined by the biasing force of regulator spring 84.
A headless screw 136 threadedly engaged in pressure regulator body 88 and extending externally and internally through a wall thereof engages the free end of lever 86. Rotation of screw 136 therefore varies the force of the closing bias of spring 84 on regulator valve 82 and consequently varies the bleed-off rate. The initial partial opening of main valve 52, which occurs upon opening of control yvalve 124, may therefore be predetermined.
Actually the initial partially open position of main valve 52 is predetermined for some particular supply pressure at inlet 12. If the instant supply pressure is above this particular pressure when control valve 124 opens, more bleed olf past the regulator valve 82 will occur and the partial valve opening movement will be less.
If, on the other hand, the instant supply pressure is below this particular pressure, the bleed off past the pressure regulator will be less and the partial valve opening movement will be greater. It will be apparent, therefore, that it is a definite portion of the full rate ilow which is predetermined and maintained constant under conditions of varying supply pressure. This portion of the full rated flow is now ignited by pilot burner 42.
The valve operating pressure which develops in main diaphragm chamber 60 shortly after the opening of control valve 124 is slowly applied to the upper surface of actuator diaphragm 102 through restricting orifice 114. The slow application of this pressure effects the slow downward movement of the central portion of diaphragm 102 and the pin 108 against the bias of return spring 104. After a predetermined interval of time, the pin 108 engages the lever 86 and continues downward, compressing spring 84 to increase the closing bias on regulator valve 82 until the free end of lever 86 engages the upper end of a lower adjusting screw 138 threadedly engaged in regulator body 88. lWhen lever 86 engages the screw 138, the closing bias on regulator valve 82 is such as to result in a bleed-off rate past the regulator valve 82 which will effect full opening or full rated flow position of main valve 52. The full rated iiow may obviously be varied by adjustment screw 138.
It will be apparent that main valve 52 will remain in its predetermined, initial, partial open position during the time interval required for pin 108 to move from its upper returned position, shown, to a position of engagement with lever 86. During this period the predetermined portion of the rated flow through valve 52 will be substantially constant, the length of this period being determined by the size of orifice 114, the volume of chamber 98, and the space between the lower end of pin 108 and lever 86. The rate of increase in the closing bias on the regulator valve, and therefore the elapsed time between engagement of pin 108 with lever 86, and the application of a maximum closing bias on `valve 82 which will effect a full rated iiow position of valve 52 will also be determined by these parameters.
The burner will now be operated at full rated fiow until sufficient heat is supplied to the space to effect opening of thermostat 132. The opening of thermostat 132 causes control valve 124 to close, thereby cutting olf communication between the inlet 12 and main diaphragm chamber 60. The existing pressure in chamber 60 and in actuator chamber 98 will now bleed off through orifice 72, and outlet passage 28, and, ultimately, to burner 15. Main diaphragm 64 will now resume its downward position shown, and main valve 52 will close under the bias of spring 69. The diaphragm 102 and pin 108 will also now resume their upper biased position, shown.
It will be understood by those skilled in the art that the stepped opening means herein described may also be used without modification in fluid pressure operated gas valves employing a system in which inlet pressure is applied to both sides of a valve operating diaphragm to effect closure of the gas valve, and in which a bleed off of pressure from one side of the diaphragm effects an opening movement of the gas valve. In these systems, which are well known and understood, a pressure regulator valve in the bleed-off passageway is biased open by a predetermined biasing force to effect a bleed-off rate resulting in opening movement of the gas valve instead of being biased closed as in the described system.
In the operation of these systems, when employing the described stepped opening means, the usual spring means biasing the regulator valve open is adjusted so as to effect a bleed-off rate which will result in an initial, predeter mined, partial opening of the gas valve when a control valve in the bleed-off line is opened. The described stepped opening means then increases the force biasing the regulator valve openward after a predetermined delay during which the operating pressure existing on the lower pressure side of the diaphragm is slowly communicated to the expansible chamber 98.
1. In a fluid pressure operated gas valve, a body member having an inlet and an outlet and means forming a main passageway therethrough connecting said inlet and outlet, a biased closed main valve controlling said main passageway, a first expansible chamber operative when expanding to move said main valve openward, a passageway including a control valve connecting said chamber with said main passageway upstream from said main valve, a bleed-off` passageway including a biased closed pressure regulator valve connecting said chamber with said main passageway downstream from said main valve and operative to bleed 0H pressure from said chamber at a rate which results in a predetermined initial opening movement of said main valve when said control valve is opened, a second expansible chamber operative when expanding to increase the closing bias of said regulator valve thereby to reduce the bleed-off rate and effect further opening of said main valve, a restricted passageway connecting said first and second expansible chambers whereby expansion of said second chamber and further opening of said main valve is slowed, and means venting said first and second expansible chambers to said main passageway downstream of said main valve thereby to permit their contraction when said control valve is closed.
2. The fluid pressure operated gas valve claimed in claim 1 in which the closing bias on said regulator valve effects an initial opening of said main valve which permits a predetermined initial flow of gas from inlet to outlet, and in which said second expansible chamber when fully expanded increases the closing bias on said regulator valve so as to effect a further opening movement of said main valve which permits a predetermined greater flow.
3. The fluid pressure operated gas valve claimed in claim 1 in which said second expansible chamber has a fully contracted position and expands freely therefrom a predetermined amount before operatively increasing the closing bias on said regulator valve, whereby the predetermined initial opening of the main valve is maintained for a predetermined interval.
4. In a fluid pressure operated gas valve, a body member having an inlet, an outlet, and means forming a passageway connecting them, a biased closed main valve controlling said main passageway, a first normally contracted expansible chamber operative when expanding to move said main valve openward, a pressure passageway connecting said chamber with said main passageway on the upstream side of said main valve, a normally closed control valve in said pressure passageway, a bleed-off passageway connecting said chamber with said main passageway on the downstream side of said main valve, a pressure regulator valve arranged to close in an upstream direction controlling said bleed-off passageway, resilient means biasing said regulator valve closed with sufiicient force to reduce bleed oif to a rate which effects an initial partial expansion of said chamber and an initial partial opening of said main valve when said control valve is opened, a second normally contracted expansible chamber operative when expanded to increase the closing bias on said regulator valve thereby to further reduce the bleed-off rate and effect full opening movement of said main valve, a passageway connecting said first and second expansible chambers including restricting means operative to slow expansion of said second chamber thereby to delay full opening of said main valve, and means venting said first and second expansible chambers to a low pressure area thereby to permit their return to a contracted position when said control valve is subsequently closed.
5. The fluid pressure operated valve claimed in claim 4 which includes means forming a lost motion operative connection between said second expansible chamber and said resilient biasing means, whereby said main valve remains in its initial partial open position for a short period of time.
6. A diaphragm gas valve in which a main valve operating diaphragm forms the movable wall of a chamber and is normally subjected to equal pressure on opposite sides thereof whereby a biased closed main valve connected thereto is permitted to close, in which 4upstream pressure is applied to the chamber through a first passageway at a predetermined rate and is bled-off to a downstream zone through a second passageway at a rate resulting in a net operating pressure effecting movement of the main valve to a desired open position when a normally closed control valve in one of the passageways is opened; the improvement which comprises the provision of an adjustably biased pressure regulator valve in said second passageway, said regulator valve having a first biased condition which results in an initial net operating pressure effecting an initial partial opening of said main Valve when said control valve is opened and a second biased condition resulting in a different net operating pressure which effects further opening of said main valve, an expansible chamber having a normally contracted condition and being operative when expanding to effect the adjustment of said regulator valve from its first to second biased condition, and restricted passageway means providing communication between said expansible chamber and a zone of net operating press-ure lying between said control valve and said pressure regulator valve, whereby the existing operating pressure is slowly communicated to said expansible chamber thereby delaying further opening of said main valve.
7. The diaphragm gas valve claimed in claim 6 in which the bias of said regulator Valve is increased from its first to second biased condition as said expansible chamber expands.
8. The diaphragm valve claimed in claim 6 in which the pressure regulator valve biasing means is a spring biased between the regulator valve and a movable member, in which said expansible chamber engages said movable member upon expanding and increases the bias on said regulator valve, and in which said expansible chamber has a lost motion operative connection with said movable member whereby it expands a predetermined amount from its contracted position before engaging said movable member thereby to provide an interval in which said main valve remains in its initial partial open position.
References Cited UNITED STATES PATENTS 3,414,010 12/1968 Sparrow 137-495 3,502,101 3/1970 Willson et al 137-495 HENRY T. KLINKSIEK, Primary Examiner U.S. C1. X.R.