US2783946A - Gas modulating and shutoff valve mechanism - Google Patents

Description

z. J. LANsKY ETAL 2,783,946

GAS MODULATING AND sHUToFF-vALvE MECHANISM Filed Sept. 25, 1953 March 5,* 1957 ulWEppf :10W/WW United States GAS MDULATING AND SHUTOFF VALVE MECHANISM Application September 25, 1953, Serial No. 382,271

4 Claims. (Cl. 236-48) The present invention relates to gas control valve mechanisms and is particularly concerned with the provision of an improved modulating and shutoff valve mechanism for controlling fuel gas supplied to a gas burner, especially of the type used for domestic space heaters, water heaters or for similar applications.

One of the objects of the present invention is to provide a single standard burner control device at low cost which can be adapted by simple adjustment to the following alternative applications: (l) snap on-snap olf, in which the gas is turned either on or olf with a snap action; (2) modulate gas ilow down to a predetermined minimum and then snap olf; and (3) modulate gas iiow between a predetermined minimum and a predetermined maximum; all of these alternative modes of operation being under the control of its own thermostatic element.

Another object is to accomplish the above without the intervention of electrical means.

Still another object is to accomplish the above by means of novel mechanism which is rugged, but suiciently sensitive to be directly actuated by a thermostatic element of the liquid filled bulb type.

Yet another object is to provide a novel and extremely simple mechanism for automatically shutting olf the iiow of gas through a modulating valve when the flow through -the modulating valve has been decreased to some predetermined minimum, thereby insuring that there will be no gas ow under conditions where combustion might not `be eiiicient or reliable.

Other objects and advantages will become apparent from the following description of a preferred embodiment `of our'invention. Y K

Referring to the drawings, in which similar characters yof reference refer to similar parts in both views: j

Figure l is a diagrammatic representation of the working elements of a valve mechanism incorporating features of the present invention, shown in vertical medial section; and

Fig. 2 is a bottom view of a snap acting valve actuating element .which is shown in section in Fig. 1. This view may be considered as taken in the direction of the arrows substantially along the line 2-2 of Fig. 1.

Gas burners, particularly gas burners for domestic space heating use, present a control problem since the systems and requirements are diverse. For instance it is frequently desirable to modulate the heat output according to requ'irements as determined by some thermostatic means; that is, to control heat output without turning the burner on and otf unnecessarily. Arrangements for exercising a modulating control, however, usually are quite complex, since they of course cannot be predicated upon the simple opening or closing of a set of electrical contacts or upon any other arrangement which simply turns the burner on and off. There is a further problem in that gas burners will only operate between certain limits of gas owa maximum which cannot `be exceeded without bringing about inecient combustion or Acausing the ame to leave the burner and become extinguished, and a miniaenf l 2,783,946 Patented Mar. 5, 1951 mum below which the burner also suffers from inefficiency and may cease functioning. Modulating arrangements, therefore, must either have some provision for shutting off the gas flow completely in the event that the flow rate 'has been modulated down below a predetermined minimum selected as appropriate for the particular burner with which the gas valve mechanism is to be used, or the burner must be modulated only between high and low limits which are satisfactory for that burner.y With the latter system the burner is not automatically turned off and in a sense acts as its own pilot. A third system iS one in which the burner is simply turned on and oi as required.

The gas valve which forms the subject matter of the present invention takes into consideration these factors and provides a safe and economical solution to the problern, and accomplishes its function purely through the use'of mechanical expedients, thereby making it feasible to operate and control the burner away from a source of electric power. By simple adjustment it can vbe adapted to give any of the control functions described above.

Referring now to the drawings, in Fig. 1V we have shown a housing indicated generally by the numeral 10. It is shown as being comprised of a main portion which may be considered as a cored and machined casting l2 to which a housing cover 14 is attached at the top. Openings which enter the bottom surface of the main portion i2; are closed by a bottom plate 16. This assembly contains the principal portions of the modulating and shutoff valve mechanism and receives fuel gas from an automatic pressure regulator 18 by way of a tube 2i). Both the modulating and shutoff operation of the valve are under the control of a temperature sen sitive liquid filled bulb 22 which ordinarily will be remotely located at some appropriate position and connected to the valve proper by a capillary tube 24. The automatic pressure regulator 18 portion of the apparatus is made up of a housing 26 having a gas inlet passage 28 which carries the fuel gas to a valve chamber A30 having a poppet valve seat 32 at its outlet. Restriction to flow through the valve seat 32 is afforded by a poppet valve 34 positioned within the chamber 30 and connected by a valve stem 36 to a exible diaphragm-38 which is loaded in the upwardly direction by a coil spring 40. This spring is held in adjusted position by a threaded spring base 42 screwed into the lower end of the housing. The diaphragm 38 serves to close one side of a chamber 44 of comparatively large diameter which is in direct communication with the valve seat 32 and with the outlet gas connection previously referred to as indicated by the numeral 20.

When this portion of the apparatus is in operation with gas flowing to the inlet fitting 28 and from the outlet, any tendency for the gas to pass through the valve seat `32 into the chamber 44 at a rate higher than is necessary to maintain the appropriate pressure in the pipe 20 will cause a slight downward movement of the diaphragm 38 under the inuence of this gas pressure. This tends to move the poppet 34 downwardly, thereby increasing the pressure drop across the vvalve seat 32. The result is that less gas hows into the chamber 44 and this reduces the pressure against the diaphragm with the result that the spring 4t) moves the poppet 34 upwardly again slightly so as to increase the ga-s ow rate. So long as gas is flowing through the valve, the valve therefore functions automatically to maintain a predetermined pressure in the outlet line 20 which of course is lower than the pressure at the inlet fitting Z8. By turning the threaded spring base 42 with a screw driver -so as to shorten the spring 4i), the gas pressure in the line 20 leading to the main regulator is increased. Con versely, backing off the plug 42 decreases the pressure in the line 20.

Gas passing to the main portion of the regulator by way of the pipe 20 enters'a chamber 46 by way of an inlet port 48. ri`he chamber is generally cylindrical in contour and is closed at a position above the port 48 by a flexible ndiaphragm 50. This diaphragm is maintained in place by an annular ring 52 having a central opening in alignment with and approximately the sam-e diameter as the chamber 46. This ring 52 is in turn sui-mounted by a cover plate 54 having an opening S6 through the centerthereof.

The diaphragm 50 is secured to an axially disposed valve stem 58 which extends upwardly through the opening '56 and'downwardly beneath the diaphragm 50 for a co'lisiderable distance. Adjacent its upper end the stem 58v has 'a split ring 60 secured thereto which rests against the 'top face of the'forked end of 1a horizontal beam 62, the 'forked end indicated at 64 -straddling the stem 58. The beam 62 extends toward 'the left as seen in Fig. l, and atits opposite end is pivoted to a horizontal hinge pin 66 such that as the forked end 64 rises and falls'by pivoting the beam 62 about the hinge pin 66, "the stem 58vrises and falls therewith, its downward movement being insured by a coil spring 68 which is disposed in the space between the upper surface of the diaphragm 50 and the lower surface of the cover plate 54 in a position concentric with the valve stem S8.

' Beneath the diaphragm 50 the stem 58 is threaded to an adjustable bushing 70, the lower end of which is rounded so as to be self centering in a conical depression 72 in the top face of a poppet valve 74. This poppet Aserves to close an opening of comparatively large diameter through a valve seat indicated at 76. Because the valve seat is large, slight upward or downward movement of'the poppet'valve 74 will have a marked iniiuence upon the rate of gas flow from the chamber 46 to the space VI8 beneath the poppet valve 74 and in communication with the valve seat 76.

The poppet valve 74 is urged upwardly so as to seat the, depression 72 against the rounded nose of the bushing 70 bya coil compression spring 80. This spring surrounds the'stem 5.8 with its upper end bearing against the lower surface of the poppet valve 74 and its lower end supported by an annular ring 82 secured to the stem 58 inv a position somewhat below the lower surface of the .poppet valve 74.`V Below the spring base 82, the lower portion of the stern 58 is guided in a machined hole S4 passing through a bracket 85 which extends outwardly from the right hand wall of the chamber 78.

Gas in the chamber 78 passes downwardly and toward the'left as seen in Fig. l and thence upwardly through a passage 86 to an outlet fitting 88, The passage 86 com rnupicates with the chamber 78 by way of a downwardly facing valve seat 90. Directly beneath this valve seat 90 there is a cylindrical recess 92 of considerably larger diameter than the seat 90, which contains a lightweight ball valve member 94 of suicient size to close the valve seat 90 when the ball 94 is in contact therewith. We preferV that the ball 94 be molded of a plastic material which is non-corrosive, light in weight, and which has a slightly resilient surface so as to form a good seal with the valve seat 90. For this purpose we have found molded nylon to be admirably suited. If desired, of course, an ordinary cup valve'witha soft seat could be used in place of this ball.

The cylindrical chamber 92, which contains the ball 94, is connected near its bottom by a drilled passage 96 to the chamber 46 and the ow through this passage is regulated by means of a screwdriver set needle valve 98 located in the passage at any convenient position.Y The arrangement is such that. as will appear, the flow of gas through the passage 96 and up around the'ball" 94 can be adjusted to tloat the ball upwardly until it is jammed against the valve seat 90. Once in this position it will of course remain closed regardless of whether the valve 74 is opened or closed unless it is pushed from it-s seat by some means. This is because if the valve 74 is open, the pressure within the chamber 78 and therefore around the bottom of the valve 94 will be the same as the pressure in the line 20 which of course will be greater than the pressure at the outlet fitting 88. If the valve y7.4 is closed, the same result will be achieved if the Vneedle valve is open because gas flowing through the passage 96 around the seat of the needle valve 98 will quickly equalize the pressures within the chambers 46 and 78. The needle valve 98 is provided so as to adjust thedevice to diterent conditions of Voperation as will `appear presently.

In order to push the valve ball 94 away from its seat, a snap acting element 100 is provided, the structure of which may best be understood by a comparison of Figs. l and 2. At its right'hand endv as seen in these igures, 'the strip is secured by an anchor screw 102 in a position somewhat'to the rightV of the lower end 104 o t' the valve stem 58. The strip extends toward the left from this position so that its opposite free end is somewhat beyond the ball 94. This free end is formed to provide a hole 106 of smaller diameter'than the ball, which surrounds theb'all, suchv that when this free end is in its upward position as shown in Fig. l the ball 94 is free to move upwardly against its seat 90, while if the free end of the strip 100 moves 'downwardly slightly, the ball will be caught in the hole 106 and moved downwardly away from its seat 90, thereby permitting 'gas to flow from the chamber 78 to the outlet 88. Movement of the'free end of the strip 100 is limited by an adjustment screw 108 which is threaded vertically into the housing so Vas to pass through an opening 110 in the strip 100 in a position just t'o the right of the'hole 106." A' portionof the adjustment screw' 108 near its outer endis turned downto small diameter to form a pair of opposed shoulders 112 which are spaced apart an appropriate distance. As shown, the hole 110 in the strip 1001s substantially the same diameter as the screw 108', but is 'so positioned with'respect to the hole for the" anchoring screw 102 that when the hole 110 is slipped over the screw 108 to a position between the shoulders 112, the strip will need to be shifted slightly toward th'e left in'order to secure the anchor screw 102. A portion of the strip to the right of the hole 110 is therefore brought between the shoulders 112 so that they effectively'limit the upward and downward movements of the free end of the strip 100 to the positions set by 'turning the screw 108.

Referring principally to Fig. 2, it will be seen that much of the right hand half of the strip 100 is formed to provide a pair of parallel slots 114 near the edges which are connected somewhat1 to the left of the center ofthe strip by cutting out a generally rectangular piece. This provides a central tongue 116 which is integral with'the strip 4101'! at' and near the anchoring screvs- 102,v but whichhas a 'free'end 118 at about the center of the strip 100. Also, th free end of the strip'100 is connected to the anchored end at 102 by a pair of comparatively thin, flexible strips 120 at each edge. The free end 118. of the tongue 116 is provided with an outwardly extending tab 122, which is directly opposite a similar tab 124 formed at the opposite end ot the opening at the center of the strip. These two tabs 122 and 124 extend through openings in aV semicircular spring metal member 126 which tendsk to straighten out to a larger diameter. It therefore exerts a compressive force acting between the free end of the tongue 118 and the main portion of the strip 1,00 at the base of the tab 124.

The' lower end 104 of the valve stem 5,8 rests against the tongue 11S in a position, slightly .to the left of this anchoring'scren 102 and, therefore, as the valve Vstein 58 descends and pushes .the free. and 113` 0f the tongue. 11,6.

arsenite downwardly, a position is eventually reached where the` free end 118 passes below the plane of the spring base at the root of the tab 124. When this happens, the compressive force of the spring 126 snaps the free end of the blade upwardly, thereby releasing the ball 94. This, as previously indicated and as will be more fully explained, permits the ball 94 to close the valve opening at the seat 90 under certain circumstances. Conversely, as the valve stem 58 rises to a certain predetermined position, the rising spring base at the tab 122 will cause the compression spring 126 to snap the free end of the blade 10G downwardly, thereby pushing the ball valve 94 away from its seat 90 and preventing it from reseating.

Just to the right of the pivot pin 66 the beam 62 has a generally spherical socket 130 formed therein in its upper surface. Directly beneath this socket the beam 62 is urged upwardly by a coiled compression spring 132 which exerts suflicient force to lift the valve stem 5S against the compressive force of the coiled spring 63 so as to open the poppet valve 74 unless the spring 132 is restrained. a

In a position above the beam 62 a corrugated metal bellows chamber 134 is located with a rounded nose 136 at its lower end in the socket 130, and with a socket 138 at its upper end embracing the conical end of an adjustment screw 140. This adjustment screw is in vertical alignment with the socket 130. The interior of the bellows 134 is connected to a capillary tube 142 which has a few turns disposed within the space about the bellows 134 to give greater ilexibility and which extends outside this space to become the previously identified tube 24 connected to the temperature sensitive bulb 22. The bulb 22, tube 24-142 and bellows 134 form a sealed hydraulic system which is filled with a liquid having a high temperature coeliicient of expansion.

The adjustment screw 140 is threaded axially through a bushing 144 which in turn is provided with external threads 146 threaded through the top 148 of the valve housing cover 14. The bushing 144 is also drilled andV tapped radially to provide for a setscrew 150 which can be tightened to secure the adjustment screw 140 against rotation relative to the bushing 144. The setscrew 150 also extends outwardly suiciently beyond the surface of the bushing so that as shown, when the bushing 144 is rotated suciently in either direction, the setscrew 150 impinges against a stop pin 152 so as to limit rotation 4of the bushing 144 to something less than one full turn. The upper end of the bushing 144 is secured to a slip-on or setscrew secured control knob 154 which may be of the type used on electronic equipment.

With this arrangement, the knob 154 can be removed from the upper end of the bushing 144 and the bushing rotated to some predetermined position such as with the setscrew 150 against the stop pin 152 for instance. Thereafter the setscrew can be loosened slightly and through the use of a screwdriver the adjustment screw 140 can be rotated inwardly or outwardly to preset the starting position for the bellows 134. During this adjustment the bushing 144 is restrained against rotation. Once the starting position has been accurately adjusted, the setscrew 15G is tightened and the knob 154 replaced. Thereafter, turning the knob 154 throughout its range of motion (as limited by the setscrew 150 and stop pin 152) will cause the bushing 144 to move inwardly or outwardly slightly as determined by the pitch of the threads 146. Ordinarily the knob 154 will carry some indicia so as to permit the user to set the valve to whatever temperature it is desired to maintain. This will usually take the form of a temperature scale which may conveniently extend from 55 F. to 85 F., or so.

As the temperature of the bulb 22 rises, the liquid therein will expand and this expansion will be communicated to the bellows 134 by way of the capillary tube 24. This will cause the bellows 134 to elongate slightly so that the nose 136 of the bellows, operating in the socket 130, will cause the forked end 64 of the lever 62 to be moved downwardly a considerably greater amount since the distance between the pivot 66 and the valve stem 58 is great as compared with the distance between the pivot and the socket 131). This releases the supportfrom be-l neath the collar 60 and permits the spring 68 to urge the poppet valve 74 downwardly so as to reduce the clearance between the valve poppet and its seat 76.' Conversely, decrease in the temperature of the bulb 22 produces opening movement of the valve poppet 74. j

The above described valve mechanism can be adjusted to eifect three types of burner control, depending upon the condtions of the particular installation.

Assuming that the system is connected between a source of gas supply and a burner and that it is desired to 21djust the system such that the control effected is of the snap-on, snap-ott type, this is accomplished in the following fashion: First of all the pressure regulator 18 is so adjusted as to supply the quantity ofl gas throughQ the system to the burner desirable for full burner operation.' Then the needle valve is so adjusted that the ow of gas' through the passage 96 is sulicient to float the ball valve element 94 upwardly against the spring 100 when downwardmovement of the poppet valve '74 is just beginning to exert a throttling effect upon the gas supply through the valve seat 76. It will be appreciated that as the poppet valve 74 exerts a throttling effect upon the main stream, the tlow rate through the bypass 96 will increase.` The original adjustment of the position of the round ended bushing .70 relative to the lower end of the stem 58 is then such that upon slight additional downward movement of the valve stem 58 the free end of the spring '100 will be snapped to the up position, thereby permitting the ball valve element 94 to float upwardly and jam in its valve seat. Upon cooling of the therinostatic bulb 22, the valve stem 58 will rise'until the free end of the spring 100 is snapped downwardly, thereby pushing the valve ball 94 away from its seat and permitting a full rate of ow of gas through the Valve mechanism.

lf it is desired to adjust the apparatus to modulate the gas flow between a predetermined maximum and a predetermined minimum and then to snap ot the gas ow below that minimum, the following procedure is'used:` As in the previous example, the pressure regulator 18 is so adjusted as to determine the maximum ow rate' through the valve system. The needle valve 98 is then' screwed all the way in so as to shut off the flow of g'as through the bypass 96. With the bulb 22 warm, the knob 154 is rotated until the poppet valve 47 has been closed suiliciently to give the minimum desired flow rate through the valve seat 76. Under these conditions the valve stern 58 will have moved downwardly somewhat more than enough to cause the free end of the spring member to snap upwardly. If necessary, the position of the bushing 70 upon the stem 58 can be shifted to` insure this. The needle valve 98 is then backedf'off until the flow rate through the bypass 96 when the *popup-eti valve is in the last described position, is just suflcienf to iloat the valve ball 94 upwardly so that-it jams in lits. seat. M

With the system adjusted as just outlined, increase in temperature at the bulb22 will cause the valve stem 58` to move downwardly until the gas supplied to the appli-'v ance has been throttled to a llow rate near the desired.: minimum; at this juncture the free end of the spring 100 will snap upwardly. Upon somewhat furtherdow'nward movement of the valve stem 58, the valve ball 94 will float upwardly and jam in its seat, thereby shutting off the appliance burner. Upon cooling of the bulb 22 thevalve stem 58 will rise until the free end of the spring blade 1G@ snaps downward, thereby pushing the ball valve 94 away from its seat and establishing gas tlow to the appliance. It will be seen that the burner will be shut ott at the minimum desired ow rate, and will be turned.

i' lusts 0.11 at a somewhat bisher rats Nate, als? that diferente! edivstbls ses ROW through the bypass l rmines .the o point While the snapping'ppint .o f the bl e determines Vthe conditions under which the burner is turned on. This is desirable since a burner in operation will usually function safely at a lower gas rate than;ttakesto'starttheburner in operation and different biieis will differ 'in this eharacteristic. "'Tf'adjust the mechanism to modulate between a ixed upper"a`nd"a lined lower limit, but without shutting oir the applianceat the lower limit, the pressure regulator' isi'djusted as previously described to establish the maximum lflow rate to the appliance. The ball 94 is removed from the device and the needle valve 9,8 is unscrewed suiciently to give the minimum desired flow rate `through the passage 96 when the puppet val 'e 74 closed. Thus, the poppet valve 7d moves upwardly and downwardly under control of the thermostatic bulb ZZ'to give a modulating control which cannot be greater than that present at the regulator i8 and which cannot lief-less than the amount which will pass through the passage 9'6. Since Ithe ball valve 94 has been removed, the snap acting leaf 160 hasno eect upon the functioning ,of he mechanism.

Eforn theY above description of a preferred embodiment of. our invention it will bev seen that variations and modifications in the structure can be made without departing from the scope and spirit of the invention and therefore theinvention is to be measured by the scope of the followin'gclaims.

" We claim:

l. A gas control valve comprising7 means forming an adjustablernodulating valve having a movable element th'e'position of which determines the rate of gas flow through said valve, a thermostatic element connected for moving said movable clement, a check valve connected ir( serie/ s low relationship to said modulating valve, means fiining a 'gas bypass around said modulating valve for closingl said check valve when the flow rate through said bypass exceeds a predetermined amount, a snap acting element adapted for holding said check valve open when in` one position and for permitting said check valve to close when in a second position, said snap acting element b' 'ng arranged to be actuated to said one position by said movable element whenever said modulating valve is opened more than a predetermined amount and to be actuated to said second position whenever said modulating valve is closed more than substantially said predeterminedamount, and adjustable restrictor means interposed irisaid bypass to preset the pressure differential across said modulating valvewhich is necessary to produce said predetermined flow rate through said bypass.

2. A Ygas control valve comprising means forming a modulating valve for regulatingl the ow of gas therethroughlaccording to the temperature of a thermostatic element, a snap acting mechanism connected to be operatedby'said modulating valve so as to be snapped in one direction when. said modulating valve is closed more than a, `tjerrnined amount and tube snapped in the opposite dlrec'tion when said modulating valve is opened more tlnsid'predetermined amount, a check valve downstreamjof said modulating valve having a movable valve element and a seat, said snap acting means being adapted when snapped in said one direction to release said movsardehecl't valve, and means forming a bypass connected valve. 'element` and when snapped in said opposite between the. upstream side of Said modulating valve and a position adjacent the upstream side of said movable valve element such lthat flow through said bypass will blow said movable valve element against its seat when said modulating valve is closed a predetermined amount, and means for regulating the ilow rate through said bypass.

3. A gas control valve comprising means forming a modulating valve for regulating the ow of gas therethrough according to the temperature of a thermostatic element, a snap acting mechanism connected to be operated by said modulating valve so as to be snapped in. one direction when said modulating valve is closed more than a predetermined amount and to be snapped in the opposite direction when said modulating valve is opened more than said predetermined amount, a check valve downstream of said modulating valve having a lightweight ball movable out of a depression and againstV a valve seat,V said snap acting means being adaptedwhen snapped in said one direction to release said ball and when snapped in said opposite direction to p ush said ball away from rsaid seat and into said depression to permit dow through said modulating valve and said check valve, and means forming a bypass connected between the upstream side of said modulating valve and a position in said depression so that gas owing through said bypass will float said ball out of said depression and against said seat, and means for regulating the ilow rate through said bypass.

4. A gas control valve comprising means forming an adjustable modulating valve having a movable element the position of which determines the rate of gas flowthrough said modulating valve, a thermostatic liquid iilled bulb and bellows mechanism having a member movable upon changes in temperature of said bulb, motion multi. plying means connecting said movable member to said movable element to cause opening and closing movement of said modulating valve as said bulb cools and warms respectively, an on-o valve comprising a movable member and a valve seat connected in series flowV relationship downstream of said modulating valve, snap acting mechanism for holding said movable member away from its seat when snapped in one direction and for conditioning said movable member for closing when-` snapped in the opposite direction, said snap acting mech-Y anism being actuated in said one direction by saidgmovable element during opening movement of said modu` lating valve when said modulating valve has reached a predetermined position and being actuated in said opposite direction by said movable element during closing movement of said modulating valve when said modulating valve has reached al predetermined position, means forming a bypass around said modulating valve forv closing said on-oir' valve when the flow rate through` said bypass reaches a predetermined level, means for adjusting the position. at which said movable element actuates said snap acting mechanism and means forad'- justingt the flow ratethroughsaid bypass.

References Cited in the leof this patent UNlTED STATES PATENTS 1,862,373 Shivers June-7, 1932.r 2,253,866 Quoos Aug. 26, 1941 2,308,275 Gauger -f Jan. l2, 1943 2332,556 Breese Oct. 26, 1943,. 2,521,277 Auber/ t Sept. 5, 1950`

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