US3461894A

US3461894A - Manually resettable safety valve

Info

Publication number: US3461894A
Application number: US497247A
Authority: US
Inventors: John R Maclennan
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1965-10-18
Filing date: 1965-10-18
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19
Also published as: DE1550313A1; BE688388A; GB1163127A; NL6614614A

Description

Aug. 19, 1969 |26 gg d; .36 3' 3s irq. -31 29 29 y 2e i `258- 59 45 I' 46 44 i! il 24 44 l i,40e 401e |4 1 I E, illegaab 28a 4 2, 28., E484 E29., F lg 3 ATTORNEY United States Patent O U.S. Cl. 137-66 9 Claims ABSTRACT OF THE DISCLOSURE A manually rotatable valve movable between o pilot and on positions in a manner to provide safe lighting of a gas burner. An actuating knob detachably latches -the valve in its on position against Ithe bias of a return spring. Coupling means is provided betweeen the knob and the valve which cooperates with a llame sensor to hold the knob and valve engaged, lbut disengages the valve from the knob and prevents reenagement thereof in the event the valve is manually rotated to its off position and an attempt is made to turn the valve to its on position before the ame sensor has had a chance to assume a no flame condition.

This invention relates to a safety device and, more particularly, to a gas valve having a thermocouple controlled safety valve that is so designed that it provides safe-lighting of a pilot burner and a main burner of a heating system. The invention is an improvement over the safety valve disclosed in an application of Keith T. Krueger, Ser. No. 455,912, tiled yMay 14, 1965 and now Patent No. 3,381,696. 'Ihis invention is directed to means to prevent a safety valve from being inadvertently moved to an off position, following safe lighting of a heating system, as to result in an extinguishing of a pilot burner and then be immediately turned on again, creating a dangerous condition. Various objects of the invention will become apparent upon reading the followng detailed description in conjunction with the accompanying drawing wherein:

FIGURE 1 is a vertical end view of the safety valve with portions thereof broken away;

FIGU-RE 2 is an enlarged cross-sectional view of the manual operating knob and the actuating mechanism between the knob and the safety valve;

FIGURE 3 is an elevational View of the stem for the knob;

FIGURE 4 is a cross-sectional view taken along line 4-4 of FIGURE 2; and

FIGURE 5 is a diagram showing the relationship of abutment means positioned on the knob and valve body, enabling the device to be operated in the desired manner.

Referring to FIGURE 1 of the drawing, the control device or valve comprises a main valve body portion 11 closed at the bottom thereof by a plate 12, with a sealing gasket 13 therebetween, and with the valve body portion being closed at its top by means of a cover plate 14, with a sealing gasket 15 therebetween. An inlet (not shown) is in the broken away portion of the valve body 11 while an outlet (not shown) is in the opposite end of the valve body, generally in alignment with the inlet. An apertured partition wall 16 lies between the inlet and outlet. A plate 17, which serves as the base of a valve subassembly, is suitably positioned over an aperture (not shown) through the wall 16 and has gas passages formed therein to conduct gas to a pilot burner outlet (not shown) and has an aperture 17a for the passage of gas -to a main burner.

Cooperating with the plate 17 and having pilot gas passages (not shown) formed therein is a rotary disc ICC type of valve 18 that is rotably mounted on the plate 17 by means of a pivot 19. This valve 18 has an aperture 20 therein that is adapted to register with the aperture 17a in the plate 17 so that when these apertures 20 and 17a are in alignment, gas can ow from the inlet to the outlet and on to the main burner. A pin 21 projects into an arcuuate groove 22 in the disc valve 18 and serves as a stop for the disc valve in its on position. The stop 21 also serves as a stop for the disc valve in its off positionv by engagement with the righthand end of the aperture 20. Formed in the face of the disc valve are a plurality of sockets 23 providing gear teeth therebetween for cooperation with a gear 24 to be presently described.

The disc valve is adapted to be rotated between its oit and on positions by means of the gear 24 having teeth thereon that cooperate with the teeth between the sockets 23 in the rotary disc and is rotable, through a coupling, by a knob 25. The knob is secured to a s-tem 26 by means of a screw 27 and the stem has an enlarged diameter portion 28 providing an abutment shoulder on the inner side of the cover plate 14 to limit the outward movement of the stem with respect to the cover plate. The knob has an annular groove 25a therein that receives a pair of resilient spring arms 29a. The annular groove has notches 30 and' 31 therein that receive the arms 29a and are adapted to yieldably hold the knob in the valve on position against the bias of a spring 32 lto be described below. The spring arms 29a extend upwardly from an apertured plate 29 that ts around the stem 26 and holds a sealing O-ring against the cover 14. The plate 29 also fits around upwardly extending bosses 33 and v34 which serve as means to limit the axial movement of the knob with respect to the cover plate. An arcuate and stepped groove 35 in the lower surface of the knob cooperates with the bosses 33 in controlling the amount of axial movement of the knob with respect to the cover at its various control positions. This groove has a deepened portion 35a at the pilot position of the knob so that the knob can be moved an additional distance with respect to the cover plate 14 for a resetting operation of the knob, which operation is to be presently described. A coil compression spring 36 normally biases the knob away from the cover 14 and resiliently holds the plate 29 tightly against the O-ring 32.

To provide for indexing of the knob and valve,

bosses

37 and 38 are provided on the shoulder between the

portions

26 and 28 of the knob stem and are positioned to cooperate with a boss 39 extending downwardly from the cover plate 14. To move the knob 25 from its olf position toward the pilot position, the knob must be depressed enough to clear the boss 39 with respect to the

bosses

37 and 38, prior to the rotation of the knob. The same is Itrue in rotating the knob from the pilot position toward the off position.

To provide for an engageable and disengageable coupling between the knob and the gear 24, the gear is provided with a cylindrical skirt portion 24a and a rectangular slot 24b. Axially slidable within the slot 24b, is a generally C-shaped member 40 positioned within the skirt portion and having a rectangular extension 40a that slidably projects through the slot 24b and terminates in a headed portion 40b. The lower end of the enlarged diameter portion 28 of the knob stem is tubular in cross-section and has diametrically opposed slots 28a which terminate at the lower ends thereof in wider slots 28b, providing abutment shoulders 28a` near the lower end of the knob stem. Axially slidable in the slots 28a is a key member 41 that has arms 42, extending transversely from the lower end thereof and within the C-shaped portion of the member 40, to positions underlying the ends 40e of the C-shaped portion. These arms 42 have recesses or notches 42a that are adapted to receive the ends 40e when the member 40e is in a lowered or reset position. The upper end of the key 41 has a short L-shaped arm 43 and a longer L-shaped arm 44 diametrically opposed to the arm 43 for engagement with beveled abutment members 45 and 46, respectively, formed on the undersurface of the cover 14. A coil compression spring 47 extends between a bridging extension between or continuation of the arrns 43 and 44 and a cross bar 48 extending between the sides of the cylindrical portion 28 near the lower end thereof. This spring normally biases the key member 41 to a raised portion. The whole coupling arrangement between the knob 25 and gear 24 is held together in a subassembly by means of a cylindrical skirt portion 14a extending downwardly from the underside of the cover 14 and a centrally apertured retaining plate 49 that engages the underside of the gear 24. The gear has a reduced diameter portion which extends through an aperture in the plate 49 to serve as a pivot for the gear. The plate is secured to the skirt portion 14a by means of screws 50.

The means for holding the knob 25 in engagement with the gear 24, other than when it is manually so held by lowering the stem 28 to position the slot portions 28h on opposite sides of the portion 40a, consists of a lever 51 that is pivoted at one of its ends 51a on a pivot 52 extending from the plate 17. The lever 51 has a key-hole slot 51a therein that is longer than the length of the head portion 401) so that the head may be inserted therethrough for easy assembly. Otherwise, the relationship of the slot with respect to the head is as shown in FIGURE 2 of the drawing, with the head 40b under the narrow portion of the slot, so that the member 40 and the lever 51 move together. The other end of the lever 51 has a forked end 51b that straddles the headed outer end 53a of an armature stem 53 which, in turn, carries at its inner end an armature (not shown) of conventional construction. The magnet, that is thermocouple energizable and is of conventional construction, is generally designated by the reference numeral 54 and is held in the valve body 11 by any suitable conventional means that is adapted to be connected to a thermocouple (not shown). A coil conipression spring 55 is positioned to bias the lever to the position shown in the drawing, wherein the C-shaped member is out of engagement with the recesses 42a.

Operation The elements of the valve are illustrated as being in the positions they would have at the time immediately following dropout of the armature, following pilot flame failure, but before the spring 32 has returned valve 18 to its off position. That is, the end 51b of the lever 51 is shown in its raised position, disengaging the ends 40C of the member 40 from the recesses 42a of the key, which disengages the gear 24 from the knob 25. This means that the valve 18 will then move under the bias of spring 32 to its closed position, with the opening 20 moved out of registration with the opening 17a through the plate 17.

Following this closure, in order to reset the valve 18 in its on position, it would be necessary to forcibly rotate the knob out of its on position, by deecting the lingers 29a out of the notches 30, and to turn the knob to the off position. To move the knob past the pilot position to the olf position, the knob has to be depressed slightly to clear the abutments or

bosses

37 and 38 from boss 39. The slotted portion 28b will only register with the opposite sides of the portion 40a when the knob is in its off position so that axial movement of the knob will cause the channel shaped portion 28th to engage the portion 40a to lock the knob and gear for turning relationship. In this position the knob may then be rotated to the pilot position, wherein the disc valve 18 will establish communication, through suitable passages therein, with the inlet and the pilot burner outlet, as provided for in the valve design of the above-mentioned Krueger application or as similarly provided in conventional commercial designs. With the valve in this position and pilot gas owing to the pilot burner, the pilot burner may be ignited and the knob depressed a sufficient additional amount to cause the boss 33 to move into deep recess 35a and the shoulder between the

slots

28b and 28a to for-ce the member 40` and the lever 51 downwardly to position the armature against the magnet. Then when the magnet is energized, the lever 51 will hold the member 40 in its lowered position. In moving to its lowered position, the ends 40C of the C-shaped member engage in the recesses 42a so that upon return movement of the knob, moving the bosses 33 out of the deep recess 35a, the gear will remain keyed to the knob through the C- shaped member and the key 41 after the slot 28b disengages from the member 40. With the knob and gear and, therefore, the valve and knob being thus held together, the knob may be rotated to the on position carrying the valve to the on position where they will be held by engagement of the spring fingers 29a with notches 30` and 31. Should the knob be raised in the pilot position before the magnet is energized, the spring 55 will cause the lever to follow the movement of the knob and keep the ends 40e out of engagement with the recesses 42a, thereby disabling the knob from being able to rotate the valve to the on position. ln rotating the valve from its off position towards its pilot and on positions, the coil tension spring 32, which is Wrapped around the edge of the disc valve, is additionally stretched so that whenever the gear is disengaged from the knob, the spring will cause the valve to move to its closed position. Therefore, as soon as the channel shaped portion 28b disengages from the sides of the portion 40a, the spring will cause the valve to close. The cooperation between the

bosses

33 and 34 and the groove 35 is such that the knob can be rotated from the pilot position to the on position withyout iirst providing the resetting of the armature and it being held due to the presence of a pilot flame.

Should the knob be rotated to the off position following the lighting of the pilot burner and the magnet being energized and holding the armature and the ends 40C of the C-shaped member being in engagement with the recesses 42a and the portion 40a spaced a greater distance from the lower end of the knob stem than is shown in FIGURE 2 of the drawing, the cam surfaces 46 and 45 will engage the ends 44 and 43, respectively, to force the key 41 downwardly to disengage the ends 40a` from the recesses 42a, freeing the valve to be rotated by the spring 32 to its oft position. Since the knob 25 cannot be lowered a sufficient distance to engage the portion 40a in the off position due to the limited movement of the knob with respect to the valve body in this position, the knob could not then be placed in operative relationship with respect to the gear to permit a resetting operation to be made. lt would be necessary for sufficient time to elapse to permit the thermocouple to be cooled down to cause dropout of the armature. With dropout of the armature, the member 40 will again be positioned at an elevation that will enable the knob to be depressed a suicient distance in the off position to again cause the slots 28b to engage the member 40 to again perform a resetting operation.

It is thus seen that the applicant has provided a mechanism between a manually operable resetting knob for a rotary safety pilot valve that will prevent resetting of the rotary valve in its on position until after a flame responsive means has assumed a no-ame condition.

Iclaim:

1. In a safety device, the combination comprising rotary valve means movable between -off, pilot and on positions; condition responsive means capable of holding but incapable of moving said rotary valve means; a manually operable knob for placing said condition responsive means in holding position for said rotary valve means and for rotating said rotary valve means; programming means arranged to keep said knob from moving said rotary valve means to its on position from its pilot position unless said condition nesponsive means is in a rotary valve means holding condition; means for biasing said rotary valve means to its off position; said knob having a construction that prevents said biasing means from returning the knob from its on position to its pilot or off position; coupling means operably located between said knob and said rotary valve means and controlled by said condition responsive means, said coupling means being so constructed that said knob and rotary valve means are interconnected when said condition exists and are disconnected when said condition ceases, to free said rotary valve means to move to its off position and prevents reconnection of said knob and rotary valve means until said condition ceases to exist, if the rotary valve means is manually closed while -the condition exists.

2. In a safety device, the combination comprising a valve body, rotary valve means in said valve body and movable between oft and on positions; condition responsive means capable of holding but incapable of moving said rotary valve means; a manually operable knob for placing said condition responsive means in holding position for said rotary valve means and for rotating said rotary valve means; means for biasing said rotary valve means to its o' position; means between said knob and valve body that prevents said biasing means from returning the knob from its on position to its off position; coupling means operably located between said knob and said rotary valve means and controlled by said condition responsive means, said coupling means being so constructed that said knob and rotary valve means are interconnected when said condition exists and are disconnected when said condition ceases to free said rotary valve means to move to its off position and prevents reconnection of said knob and rotary valve means until said condition ceases to exist, if the rotary valve means is manually closed while the condition exists.

3. In a safety device, the combination comprising rotary valve means movable between off and on positions; condition responsive means capable of holding but incapable of moving said rotary valve means; a manually operable knob for placing said condition responsive means in holding position for said rotary valve means and for rotating said rotary valve means; means for biasing said rotary valve means to its off position; said knob having a construction that prevents said biasing means from returning the knob from its on position to its o position; coupling means including a slidable latch means operably located between said knob and said rotary valve means and controlled by said condition responsive means, said coupling means being so constructed that said knob and rotary valve means are interconnected when said condition exists and are disconnected when said condition ceases, to free said rotary valve means to move to its off position and prevents reconnection of said knob and rotary valve means until said condition ceases to exist, if the rotary valve means is manually closed while the condition exists.

4. The combination defined in claim 3 wherein said latch means includes one part slidably keyed to said knob and another part slidably keyed to said rotary valve means.

5. In a safety valve having a valve body with an inlet 'and an outlet, and a partition wall in said body between said inlet and outlet with an aperture therethrough, the combination comprising a rotary valve means for cooperation with said wall aperture to control fluid flow through the valve body, a rotatable shaft for actuating said rotary valve means between an ott position and an on position, means arranged to yieldably bias said rotary valve means to its ofi position, motion transmitting means between said shaft and said rotary valve means, said motion transmitting means including an engageable and disengageable coupling means that in a first position permits relative movement of said rotary valve means with respect to said shaft and in a second position provides a driving connection therebetween, condition responsive means for sensing a safe condition and holding said coupling means in its second position as long as said safe condition exists and for causing said coupling means to `move to its first position if said safe condition terminates, and programming means between said body and shaft that is so arranged that said shaft can be moved to place said coupling means in driving relationship with said rotary valve means only when said rotary valve means is in its off position, and said coupling means is in its first position, said programming means including means to prevent movement of said rotary valve means from its off position toy its on position unless said coupling means is in its second position and prevents reconnection of said knob and rotary Valve means until said condition ceases to exist, if the rotary valve means is manually closed while the condition exists.

6. In a safety valve having a valve body with an inlet and an outlet, 'and a partition Wall in said body between said inlet and outlet and having an aperture therethrough, the combination comprising rotary valve means for cooperation with said wall aperture to control fluid flow through the valve body, a rotatable shaft for actuating said rotary valve means between an olf position and an on position, means arranged to yieldably bias said rotary valve means to its off position, motion transmitting means between said shaft and said rotary valve means, said motion transmitting means including an en- -gageable and disengageable coupling means having one portion keyed to said shaft and another portion keyed to said rotary valve means and so arranged that in a first position, said coupling means permits relative movement of said rotary valve means with respect to said shaft and in a second position provides a driving connection therebetween, condition responsive means for sensing a safe condition and holding said coupling means in its second position as long as said safe condition exists and for causing said coupling means to move to its first position if said safe condition should terminate, and programming means between said body and shaft that is so arranged that said shaft can be moved to place said coupling means in driving relationship with said rotary valve means only when said rotary valve means is in an off position and said coupling means is in its first position, said programming means including means to cause disengagement of said coupling means where said rotary valve means is manually moved to its off position from its on position while said condition responsive means is holding said coupling means in its second position.

7. In a safety valve having a valve body with an inlet and an outlet, and a partition wall in said body between said inlet and outlet with an aperture therethrough, the combination comprising rotary valve means for cooperation with said wall aperture to control fluid flow through the valve body, a rotatable shaft for actuating said rotary valve means between an off position, a pilot position 'and an on position, means arranged to yieldably bias said rotary valve means to its off position, motion transmitting means between said shaft and said rotary valve means, said motion transmitting means including an engageable yand disengageable coupling means that in a first position permits relative movement of said rotary valve means with respect to said shaft and in a second position provides a driving connection therebetween, condition responsive means for sensing a safe condition and holding said coupling means in its second position as long 'as said safe condition exists and for causing said coupling means to move to its first position if said safe condition should terminate, and programming means between said body and shaft that is so arranged that said shaft can be moved to place said coupling means in driving relationship with said rotary valve means only when said rotary valve means is in an off condition, said programming means including means to provide for movement of said rotary valve means to its pilot position but to prevent movement of said rotary valve means to its on position from said pilot position unless said condition responsive means is holding said coupling means in its second position and prevents reconnection of said knob and rotary valve means until said `condition ceases to exist, if the rotary valve means is manually closed while the condition exists.

8. The combination dened in claim 7 wherein said coupling means comprises two latchable and relatively slidable members with one slidably keyed to said shaft and the other slidably keyed to said rotaryvalve means.

r9. The combination defined in claim 8 wherein said rotatable shaft provides a driving connection with said other member when the shaft is in engagement with the rotary valve means in its off position, the shaft and said one member provide driving connection with said other member when the shaft is in the pilot position placing the condition responsive means fin its holding condition,

and said other member only providing a `driving connection between said shaft and said one member when said shaft is disposed between the pilot and the on positions of said rotary valve means.

References Cited UNITED STATES PATENTS WILLIAM F. ODEA, Primary Examiner RICHARD GERARD, Assistant Examiner U.S. C1. X.R. 251-68; 431-84