US3578243A - Stepped-flow gas valve - Google Patents

Abstract

Two, series arranged, biased closed valves in a fuel passageway and a bypass around the downstream valve to provide a partial flow when the upstream valve is open and the downstream valve is closed, the downstream valve being opened by the fluid pressure in the passageway between the valves when the upstream valve is open and the opening of the downstream valve being delayed so as to provide a partial flow of fuel for a short period following the opening of the upstream valve.

Description

United Statesi'Patent John J. Love St. Louis, M0.

June 13, 1969 May 1 l, 1971 Emerson Electric Co. St. Louis, Mo.

lnventor Appl. No. Filed Patented Assignee STEPPED-FLOW GAS VALVE 6 Claims, 1 Drawing Fig.

US. Cl 236/80,

Int. Cl G05d 23/185 Field of Search 236/ 803 137/614. 19

[56] References Cited UNITED STATES PATENTS 2,207,978 7/1940 Gauger 236/80 2,262,823 1 H1941 Steams..... 236/80UX 2,262,825 1 H1941 Welliver 236/9 Primary Examiner-Edward J. Michael Alt0rneyCharles E. Markham ABSTRACT: Two, series arranged, biased closed valves in a fuel passageway and a bypass around the downstream valve to provide a partial flow when the upstream valve is open and the downstream valve is closed, the downstream valve being opened by the fluid pressure in the passageway between the valves when the upstream valve is open and the opening of the downstream valve being delayed so as to provide a partial flow of fuel for a short period following the opening of the upstream valve.

STEPPED-FLOW GAS VALVE This invention relates to gas valves for controlling the operation of gas burners, and particularly to the type which operate automatically upon demand for burner operation to supply gas at a relatively low rate for a short period and thereafter to supply it at the full rate, thereby to effect quieter ignition of the burner and to preclude flame rollout due to insufficient combustion air.

Heretofore, it has been customary to effect the supply of gas to a burner in two steps, separated by a short time interval, by initially opening a valve part way to provide a low flow step and then, following a short delay, opening the valve further or to its full open position to permit a full flow. Representative arrangements of this method of providing stepped flow are shown and described in U.S. Pat. No. 3,300,174, issued Jan. l2, 1967, to D. C. Urban et al., and U.S. Pat. No. 3,090,592, issued May 2 l I963, to Thomas P. Fleer.

Difficulty has been experienced in obtaining and maintaining the desired initial flow in arrangements employing the stepped opening of a single valve. This is due to the fact that a very precise partial opening movement of the customarily employed poppet-type valve is required to obtain the desired flow, any slight variation in the position of the valve at this point of opening results in a considerable variation in flow. Moreover, the attachment of a poppet-type valve to its actuator is usually such as to permit some universal free movement of the valve to insure its proper seating, and this free universal movement of the valve frequently results in a slight tilting of the valve. When tilting occurs in a partially open position it appreciably affects the rate of flow.

An object of the invention is to provide a generally new and improved gas valve which upon demand for operation of a gas burner automatically supplies gas to the burner initially and for a predetermined period of time at a relatively low rate, which has been predetermined to insure safe and quiet ignition of the burner, and thereafter supplies gas at a relatively high rate until demand for burner operation is satisfied.

A further object is to provide a fluid-pressure-operated valve device which upon demand for burner operation automatically supplies gas to the burner initially and for a predetermined period of time at a predetermined relatively low rate, and thereafter supplies gas at a predetermined relatively high rate irrespective of the supply source pressure.

A further object is to provide a stepped-flow gas valve having two, series arranged, biased closed valves in a fuel passageway, the upstream one cutting off all flow when closed and being operated between closed and open positions, the downstream one permitting a predetermined flow thereby when in its closed position and being operated, after a delay, from its closed to an open, full flow position by fluid-pressureresponsivc means in response to the pressure in said passageway between said valves when the upstream valve is opened.

A further object is to provide a stepped-flow gas valve having two, series arranged, biased closed valves in a fuel passageway and a bypass around the downstream valve permitting a relatively low flow of gas for ignition when the downstream valve is closed and the upstream valve is opened, in which the downstream valve is opened by the fluid pressure in the fuel passageway between the valves when the upstream valve is opened, and in which the opening of the downstream valve is delayed for a predetermined time interval following the opening of the upstream valve.

A further object is to provide a stepped-flow gas valve having two, series arranged, biased closed, fluid, pressure operated valves in a fuel passageway and means bypassing the downstream valve to permit a relatively low rate of flow of gas for ignition when the upstream valve is'opened while the downstream valve is closed, in which the upstream valve is opened a predetermined amount by regulated supply line pressure, in which the downstream valve is opened by the pressure existing in the fuel passageway between the valves when the upstream valve is open, and in which an adjustable blecdoff rate is provided to variably delay opening of the downstream valve following opening of the upstream valve.

Further objects and advantages will appear when reading the following description in connection with the accompanying drawing.

The single FIG. of the drawing is a cross-sectional view of a stepped-flow gas valve constructed in accordance with the present invention and is shown associated with a gas burner to which it supplies fuel.

Referring to the drawing in more detail, the device has a valve body generally indicated at 10 comprising a main body section 12, a lower body section 14, and an upper body section 16 suitably connected to the main body section 12. The main body section 12 is provided with an inlet 16 in the lower left side thereof, which is screw threaded for attachment 'therein ofa fuel supply conduit, and an outlet 18 in the lower right side thereof, which is screw threaded for attachment of a fuel conduit 19 leading to a gas burner-20 having a metering orifice 21.

A tapered bore 22 entering from the upper surface of main body section [2 receives in seating engagement a tapered, hollow, rotary plug cock 24. The main and lower body sections 12 and 14 are providedwith opposed recesses forming upper and lower chamber-26 and 28, respectively, separated by a flexible diaphragm member 30. The upper-and main body sections [6 and 12 are also provided with opposed recesses forming upper and lower chambers 32 and 34, respectively, separated by a flexible diaphragm 36.

The upper chamber 26 communicates with the tapered bore 22 through a main inlet passageway 33, and it communicates with lower chamber 34 through an intermediate main passageway 38. The lower chamber 34, in turn, communicates with the outlet 18 through a main outlet passageway 40. The hollow plug cock 24 has a port 42 in the wall thereof which completes communication between inlet 16 and chamber 26 when the plug cock is rotated to the open position shown, wherein the port 42 is in registry with the passageway 33.

A main disc valve 44 attached to the central portion of diaphragm member 30 cooperates with a valve seat 46 formed in chamber 26 around the lower end of passageway 38, thereby to control the flow from chamber 26. Disc valve 44 is biased closed on its seat 46 by a spring 45. A perforated disc valve 48, slidably carried on a valve stem 50, cooperates with a valve seat 52 formed in chamber 34 around the end'of passageway 40 to control the flow from chamber 34. The disc valve 48 is held downward on its seat 52 by a shoulder 51 formed on valve stem 50.

Communication between main inlet passageway 33 and lower chamber 28 is provided by passages 54, 56, and connecting chamber 58. This communication is, however, restricted by a calibrated orifice 60. Communication between lower chamber 28 and-main outlet passage 40 via chamber 34 is also provided and comprises the passage 56, chamber 58, a port 6] leading to a chamber 62 of a pressure regulator generally indicated at 64, a passageway 66, a valve chamber 68, a passage leading to chamber 34, an adjustable passage 112, and a passage 72.

The chamber 62 of'prcssure regulator 64 is formed as a recess in the upper surface of main body section 12, which is enclosed by a flexible diaphragm member 74. The pressure regulator port 60 is controlled by a valve 76 connected by a valve stem 78 to the central portion of diaphragm member 74. The pressure regulator 64 further includes a domed cover member 80 suitably attached to the main body section 12. The pressure regulator diaphragm 74 is biased downward by a spring 82. The spring 82 bears at its lower end against the central portion of diaphragm 74 and at its upper end against an adjustment screw 84..The screw 84 is threadedly engaged in an upper, internally screw-threaded, neck portion of cover member 80. The chamber formed in the domed cover 80 above the diaphragm 74 is vented to atmosphere by a vent 86 in cover member 80.

The central portion of diaphragm member 36, dividing chambers 32 and 34, is biased downward, and the disc valve 48 is biased on its seat 52 by a relatively light spring 88. The valve stem 50 attached to the central portion of diaphragm 36 is further provided with a flange 90 at its lower end. A relatively light spring 92 supports the perforated disc valve 48 in vertical spaced relationship with the flange 90. The spring 92 does not have sufficient free length or strength at its free length to hold valve 48 off of its seat 52 when equal pressure exists on both sides of diaphragm 36 and when diaphragm 36 is moved to its downward position as shown by spring 88. The purpose of spring 92 will be described hereinafter in connection with the description of the operation of the device.

The valve chamber 68 connecting the ends of passages 66 and 70 has a valve 94 therein cooperating with a seat 96 surrounding the upper end of passage 70. The valve 94 is connected by a stem 98 to the plunger of a solenoid 100 and is biased closed on its seat 96 by the weight of the solenoid plunger. The solenoid 100 is energized through a circuit which includes electrical power source terminals 102 and a thermostatic switch 104, the thermostatic switch being responsive to temperature changes in the space heated by gas burner 20.

The upper chamber 32 is vented to atmosphere through passages 106 and 108. the effective area of vent passage 106 being manually variable by means of a screw-threaded needle valve 110.

The passage 112 together with the perforations in disc valve 48 provide communication between chamber 34 and main outlet passageway 40 when disc valve 48 is closed. A screwthreaded needle valve 114 provides means for varying the effective area of the bypass passage 112.

OPERATION The device is shown in an off" position, with the thermostatic switch 104 in an open, satisfied condition and the valve 94 closed. The hollow. rotary, plug valve 24 is, however, in an open position with its port 42 in registry with main inlet passageway 32.

When the elements of the device are in these positions, full supply line pressure is applied to both sides of diaphragm 30 and to the underside of the diaphragm 74 of pressure regulator 64. This permits spring 45 to bias main valve disc 44 closed on its seat. thereby cutting off all flow of fuel to gas burner 20. it will be noted that the greater area on the lower side of diaphragm 30, exposed to this line pressure when valve 44 is closed on its seat, acts to supplement the force of spring 45 in holding valve 38 tightly on its seat.

When under these conditions the thermostatic switch 104 closes in response to a temperature drop in the space being heated by burner 20, it effects the energization of solenoid 100 and, consequently, the opening of valve 94. When valve 94 opens a pressure drop occurs in the pressure regulator chamber 62 which permits regulator spring 82 to open the valve 76 an amount predetermined by the adjustment of spring 82. This predetermined opening of regulator valve 76 results in a bleed off of pressure from lower chamber 28 at a sufficiently greater rate than it can be maintained by the flow from the inlet through restricting orifice 60 to drop the pressure in chamber 28 and permit the line pressure being applied above diaphragm 30 to open the main valve 44 a predetermined amount.

Fuel now flows to the outlet 18 through the perforations in disc valve 48 and through adjustable passage 112 at an initial relatively low rate predetermined by the adjustment of pressure regulator spring 82. It will be noted that the pressure regulator is responsive to the pressure in chamber 34 to maintain a preselected pressure therein so that, in turn, a corresponding lower pressure at the outlet 18, due to the pressure drop across the restricting perforations in disc valve 48 and passage 112, will be maintained irrespective of inlet supply pressure changes.

The opening of valve 44 and the attending pressure increase in chamber 34 effects an upward movement of the central portion of diaphragm 36 and the valve stem 50 attached thereto. The disc valve 48, however, is held downward on its seat by this increase in pressure in chamber 34 compressing light spring 92. The spring 92, being relatively light, requires compression to substantially its solid height before the valve 48 is lifted off its seat 52 by the upward movement of the central portion of diaphragm 36. The time required for the central portion of diaphragm 36 to move upward sufficiently to compress spring 92 sufficiently to lift the valve 48 off its seat provides an interim period during which the initial, predetermined, relatively low flow of gas passing through the perforations in valve 48 and passage 112 is supplied to the burner 20 for ignition. This flow constitutes the initial flow step, and it may be varied by adjusting needle valve 114.

It will be understood that all of this initial flow may he passed through perforations in the valve 48 if desired, or the valve 48 may have a partially open position in which it is normally biased, or all ofthe flow constituting this initial step may be passed through by a bypass passage such as passage 112. In this latter arrangement disc valve 48 would be imperforate and completely closed on its seat.

The length of the period during which fuel is supplied to the burner at the initial flow rate may be varied by adjusting the needle valve so as to vary the rate at which air being compressed in upper chamber 32 can be exhausted to the atmosphere through vent passages 106 and 108.

When the central portion of diaphragm 36 has moved upward sufficiently to compress spring 92 substantially to its solid length and lift valve 48 off of its seat, the fluid pressure on top of disc valve 48 is removed and the relatively light spring 92 will now again extend and move valve 48 upward a substantial amount above seat 52 to permit free flow to outlet passageway 40. Fuel now flows at a higher rate to the burner as predetermined by the adjustment of regulator 64. This con stitutes the second step of the stepped flow operation of the device. Some force is of course required to compress spring 88 and hold valve 48 open, so that some pressure drop will result across valve 48. However, a tight seal of valve 48 on its seat is not required to prevent hazardous leakage so that the spring 88 can be made quite light, thereby to minimize the pressure drop.

When sufficient heat has been supplied to the space by the operation of burner 20, the thermostatic switch 104 will again open, causing valve 94 to close and cut off the bleed from chamber 28. Supply line pressure will now again be applied to both sides of diaphragm 30 and valve 44 will be closed by biasing spring 45. With the closing of valve 44, the pressure in chamber 34 drops to atmospheric, and the spring 88 moves the central portion of diaphragm 36 downward and moves valve 48 downward into engagement with seat 52.

It will occur to those skilled in the art that the upstream valve may be operated by means other than a pressure-responsive diaphragm. For example, the upstream valve may be operated between closed and full open positions by a solenoid and the flow during both steps controlled by a conventional pressure regulator interposed in the supply line or incorporated in the body of the device at a point in the main fuel passageway upstream from main valve 44.

The foregoing description of one form of the invention is intended to be illustrative, not limiting, the scope of the invention being set forth in the appended claims.

lclaim:

1. A steppedflow gas valve device comprising a valve body having an inlet, an outlet, and a main fuel passageway therein connecting said inlet and outlet, two biased closed valves spaced in series arrangement in said passageway controlling the flow therethrough, temperature-responsive means operative in response to temperature change to effect the opening and closing of the upstream valve, means bypassing the downstream valve and operative to permit a partial flow through said valve body when said upstream valve is opened and said downstream valve is closed, fluid-pressure-responsive means operating indepeniently of said temperature-responsive means and of said upstream valve, and between atmosphere and the pressure in said passageway between said valves, and being operative in response to the pressure increase in said passageway between said valves occurring when said upstream valve is opened to open said downstream valve, means restricting communication between atmosphere and one side of said pressure-responsive means thereby to slow its response to said pressure increase, and means forming a lost motion, operative connection between said pressure-responsive means and said downstream valve thereby to delay the opening of said downstream valve following the opening of said upstream valve, whereby low and high rate flow steps are defined.

2. A stepped-flow gas valve device as set forth in claim I in which means bypassing said downstream valve comprises a passageway connected at one end to said main passageway at a point between said valves and at its other end to said main passageway at a point downstream from said downstream valve and including means to vary the flow therethrough.

3. A stepped-flow gas valve device as set forth in claim I in which said means bypassing said downstream valve includes at least one perforation in said downstream valve,

4. A stepped-flow gas valve device as set forth in claim 1 in which said fluid-pressure-responsive means includes a movable wall, a member movable with said wall, and resilient means forming an operative connection between said member and said downstream valve. whereby said resilient means is required to be substantially stressed to effect the opening of said downstream valve from its closed position against the pressure in said passageway between said valves.

5. ln a fluid, pressure-operated, stepped-flow, gas valve device, a valve body having an inlet. an outlet, and a main passageway connecting said inlet andoutlet, two, spaced, series arranged. biased closed valves in said main passageway, means bypassing the downstream valve and permitting a predetermined partial flow from said inlet to said outlet when said upstream valve is open and said downstream valve is 6 closed, a fluid-pressure-responsive actuator for each of said valves operative to move its respective valve openward when the fluid pressure is sufficiently higher on one side thereof than on the other, means providing free communication between said inlet and one side of said upstream valve actuator and means providing relatively restricted communication between said inlet and the other side of said actuator, a bleed passage extending from said other side of said upstream valve actuator to an area of relatively low pressure, a control valve insaid bleed passage movable to open and close said bleed passage, a pressure regulator in said bleed passage operative to permit a bleedoft' rate which will effect an opening of said upstream valve when said bleed passage control valve is opened, said downstream valve actuator being arranged to operatebetween atmosphere and the pressure in said main passageway between said valves to open said downstream valve in response to the pressure increase therein when said upstream valve is opened, said downstream valve actuator having restricted communication with atmosphere and having a biased position, and means forming a lost motion connection between said downstream valve and its actuator when in its biased position whereby a delay in the opening of said downstream valve following the opening of said upstream valve is effected and defines partial and full flow steps,

6. A stepped-flow gas valve device as set forth in claim 5 in which said pressure regulator controlling said bleed passage operates between atmosphere and the pressure in said bleed passage to control the flow therethrough, and in which said bleed passage extends from and provides communication between said other side of said upstream valve actuator and said main passageway at a point between said upstream and downstream valves, whereby both partial and full flow steps are regulated.

Claims (6)

1. A stepped-flow gas valve device comprising a valve body having an inlet, an outlet, and a main fuel passageway therein connecting said inlet and outlet, two biased closed valves spaced in series arrangement in said passageway controlling the flow therethrough, temperature-responsive means operative in response to temperature change to effect the opening and closing of the upstream valve, means bypassing the downstream valve and operative to permit a partial flow through said valve body when said upstream valve is opened and said downstream valve is closed, fluid-pressure-responsive means operating independently of said temperature-responsive means and of said upstream valve, and between atmosphere and the pressure in said passageway between said valves, and being operative in response to the pressure increase in said passageway between said valves occurring when said upstream valve is opened to open said downstream valve, means restricting communication between atmosphere and one side of said pressure-responsive means thereby to slow its response to said pressure increase, and means forming a lost motion, operative connection between said pressureresponsive means and said downstream valve thereby to delay the opening of said downstream valve following the opening of said upstream valve, whereby low and high rate flow steps are defined.

2. A stepped-flow gas valve device as set forth in claim 1 in which means bypassing said downstream valve comprises a passageway connected at one end to said main passageway at a point between said valves and at its other end to said main passageway at a point downstream from said downstream valve and including means to vary the flow therethrough.

3. A stepped-flow gas valve device as set forth in claim 1 in which said means bypassing said downstream valve includes at least one perforation in said downstream valve.

4. A stepped-flow gas valve device as set forth in claim 1 in which said fluid-pressure-responsive means includes a movable wall, a member movable with said wall, and resilient means forming an operative connection between said member and said downstream valve, whereby said resilient means is required to be substantially stressed to effect the opening of said downstream valve from its closed position against the pressure in said passageway between said valves.

5. In a fluid, pressure-operated, stepped-flow, gas valve device, a valve body having an inlet, an outlet, and a main passageway connecting said inlet and outlet, two, spaced, series arranged, biased closed valves in said main passageway, means bypassing the downstream valve and permitting a predetermined partial flow from said inlet to said outlet when said upstream valve is open and said downstream valve is closed, a fluid-pressure-responsive actuator for each of said valves operative to move its respective valve openward when the fluid pressure is sufficiently higher on one side thereof than on the other, means providing free communication between said inlet and one side of said upstream valve actuator and means providing relatively restricted communication between said inlet and the other side of said actuator, a bleed passage extending from sAid other side of said upstream valve actuator to an area of relatively low pressure, a control valve in said bleed passage movable to open and close said bleed passage, a pressure regulator in said bleed passage operative to permit a bleedoff rate which will effect an opening of said upstream valve when said bleed passage control valve is opened, said downstream valve actuator being arranged to operate between atmosphere and the pressure in said main passageway between said valves to open said downstream valve in response to the pressure increase therein when said upstream valve is opened, said downstream valve actuator having restricted communication with atmosphere and having a biased position, and means forming a lost motion connection between said downstream valve and its actuator when in its biased position whereby a delay in the opening of said downstream valve following the opening of said upstream valve is effected and defines partial and full flow steps.

6. A stepped-flow gas valve device as set forth in claim 5 in which said pressure regulator controlling said bleed passage operates between atmosphere and the pressure in said bleed passage to control the flow therethrough, and in which said bleed passage extends from and provides communication between said other side of said upstream valve actuator and said main passageway at a point between said upstream and downstream valves, whereby both partial and full flow steps are regulated.

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