US2966162A

US2966162A - Gas control

Info

Publication number: US2966162A
Application number: US737083A
Authority: US
Inventors: Henry F Alfery; Richard K Engholdt
Original assignee: Erie Manufacturing Co
Current assignee: Erie Manufacturing Co
Priority date: 1958-05-22
Filing date: 1958-05-22
Publication date: 1960-12-27
Anticipated expiration: 1977-12-27

Description

Dec 27, 1960 Filed May 22, 1958 H. F. ALFERY ETAL 2,966,162

GAS CONTROL 2 Sheets-Sheet 1 INVENTOR. Hcunv E ALFREV RIGHARD. K Bum-Ian:

Arromuflv United States Patent GAS CONTROL Henry F. Alfery, Hales Corners, and Richard K. Engholdt, Milwaukee, Wis., assignors to Eric Manufacturing Co., Milwaukee, Wis, a corporation of Wiscousin Filed May 22, 1958, Ser. No. 737,083

10 Claims. (Cl. 137-66) This invention relates to gas controls of the type having a safety pilot mechanism for shutting off flow to main and pilot burners when the pilot burner is extinguished. Controls of this type are customarily provided with a safety interlock mechanism preventing flow to the main burner during the resetting of the safety valve. The present invention relates to such an interlock which is simple and reliable and permits use of low cost valves as compared to the structures in the prior art.

The principal object of this invention is to provide a safety interlock of the type described which will permit use of low cost valves.

Another object of this invention is to provide a safety interlock of the type described which is compatible with a cam operated valve structure achieving rapid shut-cit of the gas flow to insure safe operating conditions.

Still another object is to provide a simple timed gas valve having a safety interlock of the type described.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the two embodiments shown in the drawings, in which:

Figure l is a section through a control provided with the interlocked main burner valve and safety valve with both valves being shown closed;

Figure 2 is a section similar to Figure 1 but shows the resetting operation;

Figure 3 is similar to Figure 1 but shows the safety valve held in the open position and the main valve to establish flow to the main burner outlet;

Figure 4 is a view taken as indicated by line 4--4 in Figure 1;

Figure 5 is a view taken from the opposite direction as indicated by line 55 in Figure 2;

Figure 6 is similar to Figure 5 but shows the position of the driver and the operating cams during the timing of a cycle; and I Figure 7 is a partial section similar to Figure 2 showing a modified structure.

Turning now to a detailed consideration of the drawings, the valve body 10 has an inlet 12, a pilot burner outlet 14 and a main burner outlet 16. Located between the inlet and the two outlets there is a valve seat 18 for safety valve 29 carried on stem 22 which is provided with the usual armature (not shown) within the housing 24 which contains a holding coil adapted to be energized by a thermocouple, all as well known in this art. Safety holding mechanisms of this type respond to a condition (heat of the pilot burner) to hold the valve 26 open but require resetting of the armature to the holding coil. Valve is biased to its seat 18 by spring 26 in the usual manner. Thus, whenever the pilot burner is extinguished, the thermocouple no longer generates a holding current and the armature is released whereupon spring 26 seats the valve.

Resetting the armature connected to valve 20 to the holding 'coil is accomplished by stem 28 which passes through the seal 36 into the timer casing 32 (the details of the timer mechanism are unimportant here). It will be noted that the timer 32 is biased outwardly by spring 34 and is prevented from rotation within chamber 36 by means of a rib 33 cooperating with a groove in the timer housing. A shaft 40 projects from the timer 32 and passes through cover 42 for connection to knob 44 which may be both rotated and depressed. Ignoring certain interlock features for the moment, it will be seen, by comparing Figure l and Figure 2, that if knob 44 is depressed the timer 32 is moved in against the bias of spring 34 and stem 28 moves in against the face of valve 26 to move the valve from its seat 18 and hold the armature against the holding coil until such time as the thermocouple generates suflicient current to hold the valve open. When this occurs the knob 44 can be released whereupon spring 34 will move the timer, knob, and stem 28 back to their original positions and leave the safety valve held in the open position with flow established to the pilot burner through outlet 14.

Flow through the main burner outlet 16 is regulated by valve 46 cooperating with seat 48. The valve is carried by crank 56 biased by spring 52, compressed between the valve body and finger 54, towards the valve seat. The vertical portion (Figure 1) of crank 50 is provided with a central slot 56 which straddles stem 28 and through which headed retaining pin 58 projects to hold the crank on the face of boss 60 in the valve body. It will be appreciated that stem 28 and retaining pin 58 cooperate to confine motion of crank 50 to a reciprocal motion. The upper portion of the crank 50 is provided with a cam follower 62 which is adapted to ride on the periphery of operating cam 64 which is carried loosely on stem 28 between drive cam 66, fixed on the pin 26, and washer 63 also fixed on the pin 28. The degree of relative motion between the operating cam 64 and the drive cam 66 is determined by the length of slot 70 in cam 64 into which drive pin 72 projects from the drive cam 66. Both

cams

64 and 66 are provided with valley or drop portions which retain in general register at all times. Thus, the operating cam 64 is provided with a valley 74 one side of which is steep and the other side of which constitutes a gradual rise portion 76 which will act (when the cams are rotated in a clockwise direction as viewed in Figure 5) to lift the outlet valve 46 open without too much effort being required on knob 44. The drive cam 66 has a valley portion 78 which generally straddles the valley and gradual rise portions of the operating cam 64. The purpose underlying the straddling nature of the valley 78 on the drive cam will be apparent from consideration of the following. After knob 44 has been rotated to open the outlet valve 46 the timer will take over and the drive pin 72 will engage the end of the slot 70 as seen in Figure 6 and start rotating the cams in unison around in a counterclockwise direction. It should be remembered that the drive to the operating cam 64 comes through the pin 72. Hence, when the follower reaches the gradual rise portion 76 of the operating cam, the force of spring 52 operating on the follower 62 through crank 50 will be sufiicient to drive the follower rapidly down the rise portion 76 while the operating cam 64 moves relative to the drive cam 66. Of course, the operating cam 64 could not accelerate far enough or be effective in getting out of the way of the follower if the valley 78 in the drive cam did not suificiently clear the operating cam valley and gradual rise portion. With the overlapping valleys the outlet valve 46 is provided with a snap action on closing even though the timer mechanism, which provides the drive, is a slow speed motion.

When the outlet valve is closed as in Figures 4 or 5,

. 3 v the two valleys on the two cams are generally aligned and, hence, are in a general alignment with web 80 on the interior of chamber 82 so that the knob 44 may be depressed with the aligned cam valleys passing over the web 80 (Figure 2). It will be appreciated that the knob 44 cannot now be rotated to open the valve since the sides of the valleys in the two cams will act to prevent such rotary motion of stem 28. Hence, the knob 44 must be released before the knob can be turned to open the outlet valve. This prevents establishing flow to the main burner during the resetting operation. After the knob is released'from the position shown in Figure 2 it may then be rotated to open the outlet valve as shown in Figure 3.

.Itwill benoted that drive cam 66 will strike the right hand edge of web 80 if the knob is depressed when the main valve is open as in Figure 3. This prevents depressing the knob 44 to, in eifect, bypass the safety mechanism after flow has been established to both burners. The only way in which the structure described 'thus far can be actuated to the reset position is to first 'turn the knob to its reset position at which time the valleys in the two cams will be in general alignment with web 80 and, hence, will not strike web 80 when theknob is depressed to effect resetting.

Figure 7 shows a modified version of the mechanism described above with the only difference being the omission of the web 80 in chamber 82. Thus, in this arrangement knob 44 can be depressed in any rotary position. It will be appreciated that as soon as the knob is depressed, the operating cam will move out from under the cam follower 62 and, hence, the outlet valve 46 will close. The parts are so related that the outlet valve will close prior to opening the safety valve. Furthermore, since the follower 62 has now moved radially inward and has moved below the operating periphery of the operating cam 64 spring 34 biasing the knob and timer to the projected position is unable to move the parts back to the fully projected position since the end' of the follower 62 will now strike the face of the operating cam 64 upon return to the projected position. Here again, the parts are so related that upon such release of the knob, the end of pin 28 has withdrawn suniciently so that it is no longer effective to act against the safety valve 20. Thus, the safety valve can fully close and achieve 100% shut oif even if the operating cam is hung up on the end of follower 62. It will be appreciated that in order to establish flow to the main burner after resetting the safety valve 20 with the knob in any position other than the reset position, it is necessary to first rotate the knob to the reset position so as to align the valleys in the two

cams

64, 66 with the follower 62 so as to permit the cams to move into operative relationship with the cam follower 62. In this modification, therefore, the resetting operation canbe carried out in any rotary position of knob 44. All that is necessary is that the knob be rotated back to the reset position in order to actually engage and open the outlet valve 46.

It should be noted that the timer cover 42 is recessed to receive the knob 44 when the knob is depressed. The depth of the receiving well in the cover 42 is such that substantially the entire periphery of knob 44 is covered when the knob is depressed in the resetting position. This arrangement makes it inconvenient to rotate the knob when the knob is in the depressed position. This has advantages in both modifications. In the ,first modification it discourages a firm, hard rotary motion being applied with the knob depressed which could damage the cams mounted on the shaft 28. Since the periphery of the knob is virtually inaccessible when the knob is depressed, a' s trong force cannot be applied to the knob. In the second modification, it tends to discourage too much manipulation of the knob while the knob is depressed. This, in turn, encourages the operator to follow the 4 recommended operating procedure which is designed to give the most satisfactory results.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

We claim:

l. A gas flow control comprising, a valve body having an inlet, a pilot outlet and a main burner outlet, a flow passage between the inlet and outlets, a safety valve and cooperating valve seat in the flow passage, condition responsive means requiring resetting for holding the safety valve open while the response condition obtains and for closing the valve when the response condition does not obtain, a poppet type main valve and cooperating valve seat in the flow passage for regulating flow to the main burner outlet, a manually rotatable and reciprocable valve actuating member mounted in the body and acting when moved inwardly to reset the safety valve, means biasing the member outwardly, means transferring rotary motion of the member to the main valve so the member acts to actuate the main valve.

2. A control according to claim 1 in which the transfer means comprises a cam associated with the member and a cam follower associated with the main valve and cooperating with the cam to translate rotary motion of the cam into axial motion of the main valve.

3. A control according to claim 2 in which the cam has a drop or valley portion in which the follower rests when the valve is closed and means fixed in the body and aligned with the valley portion of the cam when the member is moved inwardly .to reset the safety valve, the dwell portion of the cam striking the fixed means in all other positions of the cam to prevent resetting the safety valve when the main valve is open.

4. A control according to claim 3 in which the cam is connected to the member by means of a lost motion drive and the member includes a timer for driving the cam to the valve closed position, the lost motion being eifective upon reaching the cam drop to allow the cam to move relative to the member and secure fast closure of the main valve.

5. A control according to claim 1 in which the transfer means comprises a cam mounted on the membed and the main valve has a cam follower riding the cam surface, said cam being disengaged from the follower when the member is moved inwardly to rest the safety valve.

6. A control according to claim 5 in which the cam has a drop portion which must be aligned with the follower to allow re-engagernent with the follower after resetting, the alignment of the cam and follower corresponding to the position in which the main valve is closed.

7. A gas flow control comprising a valve body having an inlet and outlets to pilot and main burners, a flow passage between the inlet and outlets, a safety valve and cooperating valve seat in the flow passage, condition responsive means for holding the valve open when the response condition obtains and requiring resetting, an actuating stem'rotatably and slidably mounted in the body, a manuallymanipulated knob connected to the stem, said stem being operative to act on the valve to reset the valve when the knob is depressed, a main valve and cooperating valve seat in the flow passage for controlling flow to the main burner outlet, a cam carried on the stem and operatively connected to the main valve to actuate the main valve when the stemis rotated.

8. A control according to claim 7 in which the main valve is connected to the cam by means of a cam follower,

resetting movement of the stem moving the cam out of engagement with the follower sothe cam cannot effect opening of the main valve during resetting.

9. A control according to claim 8 inwhich the cam has a drop or valley portion in which the follower lies when the main valve is closed.

10. A control according to claim 9 in which the body is provided with a stop which is aligned with said cam drop portion when the main valve is closed, the cam drop portion sliding over the stop during resetting, said cam having a dwell portion which strikes the stop and prevents resetting when the main valve is open.

References Cited in the file of this patent UNITED STATES PATENTS Allenbaugh July 23, 1940 Wantz May 11, 1943 Mueller July 26 1949 Macgeorge Mar. 27, 1951 Engholdt June 12, 1951 'UNETED STATES PATENT OFFICE CERTIFIGATION GF CGRRECTWN Patent No.: 2,966 l62 December 27 1960 Henry Fe Alfery et ale It is Hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4L, line 416 for "membed" read me member -g line 49 for "rest read reset o Signed and sealed this 30th day of May 19610 (SEAL) Attest:

ERNEST W. SWIDER DAVID L LADD Attesting Officer Commissioner of Patents