US2134083A - Control mechanism for gas burners - Google Patents

Description

25, 1933. a. A. GUENTHER ET AL 134,083

CONTROL MECHANISM FOR GAS BURNERS Filed June 18, 1936 2 Sheets-Sheet 1 ATTORNEYS Oct. 25, 1938. G. A. GUENTHER Er AL 2,134,933

CONTRQL MECHANISM FOR GAS BURNERS Filed June 18, 1936 2. Sheets-Sheet 2 4 i INVENTORS ATTORNEYS Patented i Oct. 25, 1938 PATENT FICE CONTROL MECHANISM FOR GAS BURNERS George A. Guenther and Howard V. Guenther; Buifalo, N. Y., assignors to Leon H. Bailou,

Lockport, N. Y.

Application June 18,

3 Claims.

the various conduits of the radiator sections ira respective of whether the flow of said gases is downward or upward.

Still another object of the invention is to provide a gas burner which will not readily become fouled up and which will, at-the same time, have a uniform mixture of air and gas at all parts of the burner head.

Numerous other collateral objects of the invention and practical solutions therefor are disclosed indetail in the herein patent specification wherein:

Fig. 1 is a diminutive side elevation, partly in section, of a complete gas heater, having our invention incorporated therein.

Fig. 2 is a side elevation of the gas? burner and associated parts.

Fig. 3 is a horizontal section through said gas burner, taken on line 3-3, Fig. 2.

Fig. 4 is a fragmentary, longitudinal, vertical section through the gas burner, taken on line 4-4, Fig. 3. j i

Fig. 5 is a transverse, vertical section through the gas burner, taken on line 55, Fig. 3.

Fig. 6 is a wiring diagram illustrating how the heater is electrically connected with other parts of the heating apparatus.

Similar characters of reference indicate like parts in the several figures of the drawings.

In its general organization, the present invention comprises a gas fired combustion chamber which is maintained at a subeatmosphere pressure by a suitable suction pump, the heat which is evolved in said combustion chamber beingtransferred to the point needed by taking the gases of combustion as they emerge from the combustion chamber and passing them through a number of radiator sections before going to the suction pump. The operation of the unit is controlled by a suitable thermostat which actuates a. gas cook which controls the flow of gas to the gas burner, said gas cook having only two positions, namely fully open or fully closed, said positions being dependent upon the requirements 1936, Serial No. 85,962

of the thermostat. The customary pilot light is used to light the main burner, and suitable provision is made to prevent any gas from going to the main burner head in the event that the suction pump should fail. Suitable provision is also made to keep the pilot light burning at all times, so as to ensure that no gas will pass out of the main burner head without become ignited. I In apparatus of this type, as previously constructed, the operation of the larger heating units was fairly reliable and satisfactory but the operation of the smaller units wa's not. In addition to this, theradiator sections of the heating units of all sizes were ineficient as to thermal transfer. In addition, the radiator sections re quired frequent cleaning out and this operation was excessively arduous and unsatisfactory.- Also the older type of gas heaters were unsafe to operate under certain conditions, and did not burn with an even fiame on the entire surface of the burners. I c

In the present invention these disadvantages have been successfully overcomein actual practice by heaters constructed as follows: In the combustion chamber it is mounted a main burner head H and a pilot burner head H2. The latter is kept burning at all times by being supplied by a suitable mixture of gas and air. The gas for said pilot is supplied from a main gas supply pipe l3 which feeds it to a pressure equalizing valve I4. The latter operates in the usual and well known manner to hold backthe gas whenever its pressure rises beyond a certain predetermined point, in the manner shown and described in detail in Patent No. 1,940,587, issued to one of the herein co-inventors, George A. Guenther. From this pressure equalizing valve the pilot gas passes through a needle valve l5, 1 where its amount of flow is regulated, and

through a feed tube l6 into a pilot mixing chamber ll where it is mixed with a suitable proportion of air and passes up a pilot riser tube Hi to aforesaid pilot burner head l2.

The air for both the pilot burner head l2 and the main gas burner head I I is brought in through I a main air cleaner 20, and passes through a main, air-adjusting valve 2|, and thence into a main air duct 22. A portion of the air at this point is bled off through a bleeding nipple 23, and passes through a pilot air adjusting valve 24 into aforesaid pilot mixing chamber l1 where, as previously described, it mixes with the pilot gas and passes to the pilot burner head l2. The main bod. of air in the main air duct 22 is conpipe 25 where it mixes with gas from a main gas duct 26 and and is mixed therewith and the mix-' ture then passes upwardly through said main burner pipe 25 to the main burner head II. It should be noted that the main air duct 22 and the main gas duct 26 are axially in alignment with each other. This means that the gas andair impact upon each other face to face at this point and are thereby veryintimately mixed without requiring any vanes or other protuberances in the bore of either of said ducts or of the main burner pipe 26. In other words, the bores or both of these ducts and the bore of the main burner pipe 25 may be constructed as smooth as may be desired to prevent the accumulation of dirt and scale, and yet the air and gas be so intimately mixed that the gas-air mixture at the main burner head ll be absolutely uniform, This is a considerable, improvement over previous burners in which a certain amount of more or less raw gas was found to creep up one or other side of the burner pipe and', as a consequenc, to either burn at the burner head with a dirty flame at some spotsfor to require such an excess of air in the mixture as to seriously reduce the thermal efllciency of the burner.

Gas for. the main burner head II is led from aforesaid pressure equalizing valve l4 through a nipple 21 to a solenoid-actuated control valve or gas cock 23. This gas cock has only two positions, namely, a fully closed position (as shown in the drawings) and a fully open position.

This gas cock is actuated in the usual and well known manner by ,-a soft-iron, cylindrical core 33 which is energized-to open the gas cock 28 whenever current is fed through the solenoid coil 3| by the closing of the switch contacts of the usual thermostat 32, as shown in Fig. 6. The electrical energy which is adapted to energize this solenoid coil 3| is preferably fed from the electric power line 33, through a main electric control switch 34,

. and through a transformer 35 and rectifler 36 to the thermostat 32 whose switch contacts are in seriesI with the contacts 31, 3' of the solenoid coil 3 Whenever the gas cock is opened by the thermostat 32, gas is allowed to pass to a manually adjustable needle valve or gas regulating valve 38, the passage of gas through which is sufliciently constricted to warrant this valve as being broadly considered an orifice, as indeed it actually would be if said valve were so constructed as to not be adjustable. The present disclosure shows an adjustable valve but it is to be understood that the invention covers the use of a "metered hole or other orifice, if so desired.

From this gas regulating valve 33 the gas passes to a suction safetyvalve 43 which, when in its open position, allows the gas to pass to the main as duct 26 where it is mixed with air from the main air duct 22, as previously described. Said suctionsafety valve 43 is actuated by a flexible diaphragm 4 l which is arranged in a diaphargm chamber 42 and is connected with the suction safety valve 43 by a shank 42!. This shank fits suflicientlyclosely in the opening. 43 of the upper wall 44 of the diaphragm chamber 42 to constitute a restricted tubular connection between the main gas duct 26, and the upper half of said diaphragm chamber. This restriction is sufficiently small in cross sectional area' to prevent any fluttering of the suction safety valve 43 but is, at the same time, sufilciently large to ensure that the pressure in the upper half of the diaphragm chamber 42 is substantially identical with the pressure existing at that moment in the main gas duct 26 and in the main burner pipe 25. The lower half of the diaphragm chamber 42 is always maintained at atmospheric pressure by the provision of a large opening 45 formed in the lower wall 46 of the diaphragm chamber.

The reason for this suction safety valve 43 is as follows: When the heater is in normal operation, all products of combustion are drawn out of the combustion chamber J3 and through a pair of radiator sections 41 by a suitable induced draft fan or suction fan 48. This fan is wired in parallel across the electric power line 33, as shown in Fig. 6, and hence operates constantly, from the time that the heating unithas been put into service, by the closing of themain electric switch 34. In the event, however, that the suction fan 48 should fail to function, then, as a consequence, the pressure in the combustion chamber [3 and in the upper half of the diaphragm chamber 42 I will rise. This will allow the suction safety valve 43 to drop, and to thereby close qfl all gas flow through the heating unit except that to the pilot burner head l2. Thereby the combustion chamher I 3 will be prevented from being burned out as a result of its heat not'being properly drawn off by the suction fan. At the same time any carbon dioxide blanketing ofthe pilot burner head I2 is prevented by the action of gravity in opening a pair of safety vent doors 53 which have erstwhile been held inwardly in their closed position against the action of gravity by the sub-atmospheric pressure in the radiatorsections 41.

In previous types of heaters of this same general character, the suction safety valve 43 has been placed in the gas line ahead of the gas regulating valve 33. This has been found only to act reliably, especially in the case of the large heating units, when the gas regulating valve 33 was opened quite wide. But when said gas regulating valve was closed to anyconsiderable extentfrom' lating valve 33which, being partially closed,

would be too small to let the wave pass quickly through, thereby causing said wave to be reflected backwardly against the upper face of the diaphragm of the safety suction valve 43. This pressure against the top of said diaphragm would cause said diaphragm to drop and this would cause the safety suction valve 43 to close. This closing would allow the pressure above the diaphragm to be released through the regulating valve and, due to this drop in pressure above the diaphragm, the safety suction valve 43 would again open. The result of this cycle of operations was a'sharp fluttering of the safety suction valve of each heating unit whenever the gas regulating valve 38 was turned down to any considerable extent. This was particularly objectionable where a considerable number of heating units were connected together, because it .would sometimes set up periodic vibrations or so--called hammer in the entire system and would sometimes even be violent enough to snuff out one or more of the pilot lights.

The suction fan 43 causes the heated gases of I combustion in the combustion chamber l3 to be "their buoyancy.

from the top of the combustion chamber Hi to the top of each of the outer radiator sections 5| by a horizontal, radiator, inlet pipe 54. This inlet pipe is threaded at its extreme outer end into the partition 55 which forms the inner wall of the outer radiator conduit 5|. The inner end of said inlet pipe 54 passes through the inner wall 56 of its companion radiator section and is connected in a gas-tight manner therewith by a soft gasket 51 which bears against the outer face of said inner wall 56 and is held firmly thereagainst by a packing nut 58 which is threaded onto the inlet pipe 54, v I

The outer conduit 5| is shown as being of tapered form with its small end down. This is advantageous in that it ensures that the gases of combustion will come into intimate contact with both the partition 55 and with the outer wallof the radiatorsection. This tapered form of conduit is not, however, essential in the case of such a downdraft conduit as this outer conduit 5|, as the flow -of gases in this particular case is contrary to the upward buoyant force of the hot gases and hence said gases are bound to firmly impinge against the walls of said outer conduit 5| even though said conduit has parallel walls or is tapered with the small end up.

The factors aifecting the intermediate conduit 52 are, on the other hand, considerably different, because this particular conduit 52 is an updraft conduit in which the flow of gases is assisted by If this conduit were bounded by parallel vertical walls or if it were tapered with the small end down, there would be a tendency,

due to the buoyancy of the hot gases, to rapidly pass up the central part of the conduit without touching the side walls. The arrangement shown prevents such an action by having the conduit 52 of tapered form with the small ehd up. With such a construction the hot rising gases, instead of being all capable of direct vertical movement,

are caused to impinge on the tapered conduit walls and to thereby be enabled to give up their heat to said walls.

It will be noted that the bottom end of the partition 55 stops considerably short of the floor of its companion radiator section. This enables dirt from both the intermediate, updraft conduit 7 52' and the outer, downdraft conduit 5| to fall into the one sump which is of such ample capacityras to not require very frequent cleaning.

. conduit 53. The latter is a downdraft conduit and hence, although preferably of tapered form with the small end down, as shown, may be of any other desired shape, just as in the case of the outer, downdraft conduit 5|. The lower end ofsaid inner, conduit 53 opens into a short, in-

tegral pipe 62 which is connected by a union 63 with a manifold pipe 64. The central part of said manifold pipe 64 is connected to a suction pipe which conveys the cooled-off gases to the suction fan 48 which is usually located in the basement of the building.

Ordinarily when cleaning the heating unit, both the upper unions 66 and the lower unions 63 are uncoupled. Dirt in the sump B0 is removed by unscrewing the dirt plug 6|,as previously described, while dirt in the sump 61 at the lower end of the inner, radiator conduit 53 is removed through the short pipe 62. This eliminates the need of a special dirt plug to enable saidsump 61 to be cleaned out.

We claim as our invention: 1. A control mechanism for a vacuum gas heater having a combustion chamber, a burner in said said conduit adjacent to said burner, an electri-- cally operated thermostatic control valve arranged in the inlet portion of said conduit, and a manually adjustable regulating valve arranged, in said conduit between said safety valve and said control valve. 7

2. A control mechanism for a vacuum gas heater having a combustion chamber, a burner in said chamber and an exhaust device connected with said chamber, comprising a gas supply conduit connected with said burner, a suction operated safety valve arranged in the outlet portion of said conduit adjacent to said burner, an electrically operated thermostatic control valve arranged in the inlet portion of said conduit, a manually adjustable regulating valve arranged in said conduit between said safety valve and said control valve, and an automatic reducing valve arranged in the inlet portion of said conduit I in advance of said electrically operated valve.

3. A control mechanism for a vacuum gas heater having a combustion chamber, a burner in said chamber and an exhaust device connected with said chamber, comprising a gas supply conduit connected with'said burner, a suction operated safety valve arranged in the outlet portion of said conduit adjacent to said burner, an electrically operated thermostatic control valve arranged in the inlet portion of said conduit, a manually adjustable regulating valve arranged in said conduit between said safety valve and said control valve, and an automatic reducing valve arranged in the inlet portion of said conduit in advance of said electrically operated valve, said suction valve including a movable closure member and a diaphragm which is responsive to the cheat of said exahust device for causing said the temperature is above normahand said reducing valve being responsive to variations in the pressure under which gas is supplied to said conduit for causing said reducing valve to move-toward its fuly closed position as the pressure of the gas in the suply rises and to move toward its fully open position as the pressure of the gas in the supply drops.

GEORGE A. GUENTHER. HOWARD V. GUENTHER.

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