US3480028A - Gas valve with a thermoelectric safety device - Google Patents

Description

Nov. 25, 1969 J. H. VAN DER ZEE 3,480,028

GAS VAIJVE WITH A THERMOELECTRIC SAFETY DEVICE Filed Feb. 5, 1967 INVENTOR. JAN H. VAN DER ZEE ATTORNEY United States Patent 3,480,028 GAS VALVE WITH A THERMOELECTRIC SAFETY DEVICE Jan H. van der Zee, Emmen, Drenthe, Netherlands, as-

signor to Honeywell Inc., Minneapolis, Minn., a corporation of Delaware Filed Feb. 3, 1967, Ser. No. 613,870 Claims priority, application Germany, Mar. 19, 1966,

Int. (:1. rzsn /24 US. Cl. 137-66 6 Claims ABSTRACT OF THE DISCLOSURE A 100% safety shut-off and safe-lighting gas valve, having a manually resettable and thermocouple energizable latching mechanism for the safety valve. In operation, a separate manual actuator is provided to deflect the latch and free the safety valve to close, without affecting the position of the remainder of the latching mechanism that otherwise would hold the valve open. The latching mechanism is such that the safety valve cannot be manually opened by the manual resetting means unless the latching mechanism is in its electrically released condition or position, where the latch can engage and pick up the safety valve.

Background of the invention Valves, of the above-mentioned type; are broadly old in the art. Examples of such valves may be seen in United States Patents Nos. 2,988,098 and 3,099,994. These valves were designed to meet the need for exceptionally safe, so called, safe-lighting means for gas burners. Older safe-lighting valves, once the heating system had been put into operation, could be manually turned off (thereby extinguishing the pilot burner) and quickly turned on again (thereby supplying unburnt gas to the combustion chamber) before the thermocouple had time to cool down enough to cause safety shut down. An effort to immediately reignite the pilot burner, with gas having thus been supplied to the furnace, occasionally resulted in a serious explosion. The above-mentioned patented devices and this invention cannot be operated in that manner.

Brief summary of invention This invention is directed to a manually resettable and safe lighting gas valve with an axially movable safety valve or control member which is held open in the presence of a pilot burner flame and is closed in the absence of a flame by means of a temperature responsive safety device having a thermocouple energizable latching mechanism. The latching mechanism in the gas valve permits opening of the valve only when the safety device is de-energized. A separate manually operable means is provided to move the latch, to free the valve from the latch of the latching mechanism, without changing the position of the remainder of the latching mechanism. This simple and inexpensive combination provides the same fool-proof operation that the more complicated and more expensive prior art combinations provide.

Description of drawings FIGURE 1 is a sectional elevational view of the preferred embodiment of the invention, in its closed position;

FIGURE 2 is a fragmentary sectional view showing the reset plunger or shaft in its depressed or resetting position;

FIGURE 3 is a view similar to FIGURE 2 wherein the reest plunger is in its retracted position and the safety valve is in its open position; and

3,480,028 Patented Nov. 25, 1969 "ice FIGURE 4 is a view similar to FIGURES 2 and 3 wherein the reset plunger is in its retracted position, the latching mechanism is being held by the thermoelectric means and the manually operable safety valve releasing plunger or shaft is depressed and is holding the latch plate and latch in their deflected 0r valve releasing positron.

Detailed description The casing of the gas valve, shown in FIGURE 1, has an inlet 2, a first outlet 4 for the main burner, and a second outlet 5 for the pilot burner. Between inlet 2 and the outlets 4 and 5 and extending through the wall 3, is a chamber or bore 37, the upper plane of which provides a seat 38 for a closing member or interrupter valve 8 and the lower plane of which provides a seat 36 for the closing member or safety valve 6. Between seats 36 and 38 the chamber 37 connects with the outlet 5 for the pilot burner (not shown).

The valve 6 has a coaxial bushing 18, on the free end of which is a shoulder or collar 17. Normally the bushing 18 is movably guided partially on the lower end of a manually operable resetting shaft or plunger 9 and partially on the upper end of an armature stem 10 which, in turn, is axially movable in a conventional thermoelectric safety until 11. This unit is screwed into the casing 1 of the gas valve. The safety unit is adapted to be connected in a well-known manner to a therrnocouple (not shown) positioned to be heated by a pilot flame. The armature of the magnet (not shown) is secured to the lower end of the stem 10.

A generally L-shaped latching member 13 is rockably mounted in a groove 19 in the stem 10 and is biased upwardly by a spring 12. A spring 7, positioned between the latching member and the valve 6, normally holds the valve 6 in its closed position against seat 36. Spring 12 is enough stronger than spring 7 as to move a latch 14 on the latching member to a position over the shoulder 17 when the armature is not being held by the magnet of the safety unit. An arm 15 projects laterally from the latching member and into alignment with a manually operable tripping plunger 16. The upper end of this plunger is biased outwardly of the casing 1 by spring 21 bearing against a knob 26. The plunger is generally parallel to the reset plunger 9, and is manually movable into engagement with the arm 15 to deflect it to the position shown in FIGURE 4 of the drawing, to free the latch 14 from engagement with the shoulder 17. Spring 7 is then able to close valve 6 even if the latch is retained by the magnet.

The resetting plunger for the valve 6 has a knob 29 on the outwardly extending end thereof and carries an axially slidable interrupter valve 8 intermediate its ends. A spring 22 nor-maly biases the knob to the retracted position shown in FIGURES 1, 3 and 4. The valve 8 is positioned between two spaced abutments 23 and 24 on the plunger 9; and an O-ring seal and spring 25, between the valve and the abutment 23, normally holds the valve against abutment 24 but permits plunger 9 to move relative to the valve 8 when the valve is seated on seat 38.

Operation Assuming that the gas valve, as illustrated in FIGURE 1, is installed in a heating system, the system may be placed in operation by depressing knob 29. In so doing the lower end of the operating shaft 9 acts on the upper end of the stem 10 and drives it against the force of the spring 12 into the safety unit 11. The armature, the latch and the valve 6 are moved downwardly with stem 10 to their reset position. The valve 8 on the operating shaft 9 also moves downwardly to seat 38 for closing the passage to the outlet 4 to the main burner. After closing seat 38,

the pressure on the knob 29 must be increased to overcome the force of the spring 25. The further pressure on the operating shaft 9, drives the stem to a position in which the latch 14 comes in contact with the shoulder 17 of bushing 18 of valve *6. By further movement, the latch member, through the latch 14, takes the bushing 18 with valve 6 from seat 36 to open the passage to the pilot burner through outlet 5, as shown in FIGURE 2.

After ignition of the pilot burner has been accomplished and an appropriate current from the thermocouple has energized the magnet of the safety unit 11, the armature and valve 6 will be held by said magnet. Now the knob 29 may be released, whereby the spring 22 returns it with the connected plunger 9 to its retracted position. In this operation, the spring 22 moves the valve 8 from the seat 38 to open it. The gas can now flow from inlet 2, through the chamber 37 to outlet 5 and to outlet 4, as shown in FIGURE 3.

The safety valve may be manually closed by depressing the knob 26 and moving the plunger 16 against arm or extension of the latch plate 13 and pivoting it a suflicient distance that the hook of the latch 14 disengages from the shoulder 17 on bushing 18 of valve 6. The spring 12 is then free to move the valve upwardly against seat 36, as shown in FIGURE 4.

The plate 13 is provided with a central aperture, the diameter of which is limited in a well-known manner by means of fixed parallel spring wires (not shown) with a distance from each other corresponding to the diameter of the rod groove 19. With the elements in the position shown in FIGURE 4, an operating or resetting try, by depressing knob 29, would be ineifecitve because the operating plunger 9 is not in abutment with stem 10, which is still being held by the armature, and latch 14 is not able to pick up valve 6.

After the magnet of the safety unit 11 is sufiiciently de-energized, the spring 12 will drive the plate 13 to the position shown in FIGURE 1. The latch, with its cam or sloped plane 28, pivots and slides in this operation on the shoulder 17 of the bushing 18 to again latch with the gas valve and be ready to be operated again.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows:

1. In a gas valve having an inlet, a pilot burner outlet, a main burner outlet, a normally closed safety valve for controlling gas flow to said burner outlets, a normally open interrupter valve for controlling gas flow from said safety valve to the main burner, temperature responsive means for holding the safety valve open only when a pilot flame is present, a bodily movable latching means for detachably connecting said temperature responsive means and said safety valve, and manually operable reset means movable on a longitudinal axis for closing the interrupter valve and opening the safety valve and resetting said temperature responsive means; the improvement in said latching means comprising a first latch member operably connected to said temperature responsive means, a second latch member operably connected to said safety valve and detachably connectable with said first latch member, one of said latch members being pivoted about an axis normal to the axis-of said reset means, means biasing said one of said latch members axially with respect to said reset means, said one latch member being biased to its latch engaging position by the same means that biases said one latch member axially, and manually operable tripping means for actuating said one of said latch members to cause separation of said latch members to free said safety valve to return to its closed position.

2. A gas valve as defined in claim 1 wherein said one latch member is a generally L-shaped member having its base portion pivoted on the temperature responsive means and the biasing means is a spring engaging said base portion.

3. A gas valve as defined in claim 2 wherein said interrupter valve, safety valve, manually operable reset means, latching means and temperature responsive means are substantially coaxial.

4. A gas valve combination as defined in claim 1 in which the manually operable means for tripping the latching means is separate from the manually operable means for resetting the safety valve.

5. A gas valve combination as defined in claim 1 in which the means for tripping the latching means is a reciprocable plunger spaced from and generally parallel to the safety valve resetting means.

6. A gas valve combination as defined in claim 5 in which said one latch member has a cam surface thereon positioned for engagement with the other latch member for temporarily deflecting said one latch member as said latch members move toward each other in a relatching operation.

References Cited UNITED STATES PATENTS 2,722,945 11/1955 Gresham 13766 XR 2,962,036 11/1960 Collins 13766 2,988,098 6/1961 Thomas 251-67 XR BILLY S. TAYLOR, Primary Examiner US. Cl. X.R.

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