US1762133A - Regulating apparatus for gas-burning equipment - Google Patents

Description

June 3, 1930. w. J. HARRB, JR

REGULATING APPARATUS FOR GAS BURNING EQUIPMENT Filed Jan; 20; 1928 M. m 3 l 3 an m n E 5 M sh 2 WJ. N. ,M 3 g Q Q w. v 3 w .3 fi. & .mw w E 2 4 ,3 FMS 3 3 Q By- !Z fl. 454 76.; ATTORNEY.

Patented June 3, 1930 uNrrEo STATES PATENT JOFFICE WILLIAM J. HARRIS, JR, TOLEDO, OHIO, ASS IGNOB TO THE SURFACE COMBUSTION COMPANY, INC., OF TOLEDO, OHIO, A CORPORATION OF NEW YORK REGULATING APPARATUS FOR GAS-BU RNING EQUIPMENT I Application filed January 20, 1928. Serial No. 248,143.

This invention relates to improi ement in regulating apparatus for gas burning equi ment and more particularly to equipment esigned for burning explosive mixtures of fuel gas and air; Equipment of this kind is used very extensively in connection with heat treating furnaces.

Where the ex losive mixture is formed by utilizing a jet 0 one of the constituent ases for entraining the required amount of the other constituent gas, the mixing tube is usually of the Venturi -type. It is customary in furnaces of the heat treating type to connect up a series of the mixers to one common supply main of the inducing gas which may be either fuel gas or air under suitable pressure. The jet orifices through which the gas is discharged into the mixers are of such size and the apparatus is otherwise so adjusted that when the equipment is functioning at full capacity a properly proportioned gaseous mixture of fuel gas and air is formed. When the furnace has been brought up to heat the supply of inducing gas is almost entirely out off, only enough gas being allowed to flow to satisfy the minimum requirements of the equipment, this minimum requirement being a sufiicient supply of gaseous mixture to prevent back flash through the burners. Heretofore the valve for cutting down on the supply of inducing gas has been of a type which is either fully open or fully closed. These valves have usuallybe'en solenoid valves under the control of the furnace temperature. These valves are so constructed that when closed a certain amount of gas may bypassed around the valve to supply the-minimum requirements of the equipment as already stated. The adjustment for passing enough gas to maintain a minimum gas pressure ahead of the mixers is madewhen all of the mixers are open to the gas supply.

Let us assumethat the whole equipment is functioning at full capacity and that due to uneven temperature distribution in the furnace, it is necessary to shut off one or more of the air gas mixers. When next the solenoid valve closes, the minimum pressure of the by-passed gas will no longer be the same as before: it will be higher because solenoidv valve remains the same as'before.

It follows, therefore, that instead of the op.- erative part of the equipment functioning at its minimum capacity, it is functioning at a capacity which is intermediate between its mnnmum and maximum capacities. When the operator notices the apparent irregularity in the minimum operation or functioning of the e uipment, he cuts down on the gas which is y-passed around the solenoid valve until the gauges at the mixers show the proper pressure which when normal city gas is used as fuel and with the type of equipmentunder consideration is usually about 3 lbs. per sq..in. At a later period it maybe necessary to again turn on the mixers which were shutoff. If this is done when the solenoid valve is open, no trouble results, that is to say, the burners do not back fire. However, when the solenoid is again actuated under the influence of the furnace temperature to shut off the as, the burners will immediately back-fire y reason of the fact that the operator previously reduced the supply of the by-passed gas to'a point which would give the required minimum pressure on such mixers as were left in condition for functioning but as usually'happens failed to readjust the apparatus to allow therequired amount of gas to pass to satisfy the minimum pressure requirement when all the mixers and consequently all of the burners were in conflowing to the inspirators or mixers irrespective' of what proportion of the mixers have been shut off. f

For a further understanding of the invention reference is made to the detailed description taken in connection with the accompanying drawing forming part of this specification.

Referring to the drawing, Fig. 1 is a more cated at 26.

' 34 suitably or less diagrammatic plan view of the gas burning eqni ment embodying my invention. Fig. 2 is a side elevation of the controlling mechanism of my invention, parts being in section.

In the drawing, 10 representsa heat treating furnace; 12, 14, and 16, three groups of burners firing into the furnace; 18, and 22, the individual Venturi mixers or inspirators for supplying the individual groups of burners with combustible gaseous mixtures;

24, the common supply manifold for the mix-- ers, 13, 15 and 17, any suitable cut-off valves between the manifold and the individual inspirators; and 1-9, 21 and 23, suitable pres sure gauges at the outlet side of the cut-off valves.

The gas admitted past the cut-off valves flows into the individual mixing tubes through gas jet orifices,' one for each inspirator as indicated at 25 in the partly sectioned apparatus. The gas supply main is indi- The above described apparatus represents a more or less standard layout of equipment as used in connection with heat treating furnaces where an explosive gaseous mixture is to be formed and burned.

In accordance with this invention I interpose in the gas main 26 ahead of the mapifpld 24 a pressure regulator or governor generally. indicated at 28. The governor may be of any suitable type but a governor of the type shown is preferred. This governor is of the balanced valve type as indicated at 29 and has a diaphragm 30 between which and the valve 29 is a valve stem 31. The under side of the diaphragm is open to the atmosphere and its top side is made subject to the pressure prevailing on the delivery side of the governor through a suitable conduit 32 as will be readily understood. For convenience of descrip tion that section of the gas main on'the delivery side of the governor may be identified by the numeral 26. I

The governor is normally open and so adjust'ed as to pass enough'gas to maintain a predetermined minimum pressure at its outlet side, this minimum pressure being that which is required to keep thebu'rner equipment functioning at minimum capacity without back-firin To permit adjustment of the governor the valve stem 31 is operatively connected as at 33 to the short arm of a lever pivoted to the governor body as at 35 and rovided with a slidable weight 36. By ad usting the, position of the weight 36 on the long arm of the lover any desired pressure at the outlet side of the governor can be obtained as will be understood without further explanation. It will now be seen that evn 1f the 'operator should disconnect one or more of the inspirators as, for example, inspirators 18 and 20, by closing the valves 13 and 15, the remaining operative equipmentwill continue to function at its normal minimum capacity in exactly the same manner as if all of the inspirators were in open communication with the manifold 24. This will be understood when it is remembered that the governor 28 is ofsuch character a's tomaintain a constant pressureon the gas flowing to the manifold; It will, of course, be understood that the equipment functions at minimum capacity only during such time as the furnace temperature is at a predetermined maximum.

In order to provide for functioning of the equipment when the furnace temperature drops below a permissible minimum, I have provided the equipment now about to be described. 40 indicates a thermocouple suitably connected to a recording and controlling instrument generallyindicated at 42. Instruments of this type are well known in the art. It is suiiicient to say that the instrument 42 is such character that it will allow a motor 44 to be energized for a certain period if the furnace temperature as indicated by the thermocouple exceeds a certain max- .a crank 46 to be rotated through one-half revolution during any given period that the motor is energized. Intel-posed between the crank 46 and the governor controlling lever 34 is a spring 48, the spring being secured "in operative position in any suitable manner but preferably by means including an adjusting element 49.. In the drawing the po sition of the mechanism indicates that the gas burning equipment is functioning at minimum capacity.

When new the furnace temperature reaches the predetermined minimum as indicated by the thermocouple, the instrument 42 will be actuated and allow the motor 44 to rotate the crankshaft 46 one-half revolution. This half revolution of the crankshaft will pull down on the spring 48 which in turn will pull down on the governor lever 34 and consequently set the governor for delivering an increased supply of gas. In other words, the governor will now be set to deliver the maximum amount of gas and will maintain a constant pressure on the gas so deliveredf Regardless of what the main line pressure may be, uniform pressure will always be maintained on the dclivcry-side of the governor andconsequently the functioning of the burner equipment will not be affected by the number of mixers or inspirators which may be in operation at any one time.

' It. will now be seen that the present invention enables the gas burning equipment to function normally at all times regardless of the fact that a certain number of the inspirators have been out off from the supply manifold. The improvement while relatively simple marks a ver decided improvement in the art in which. it is made. As previously indicated the particularly details of the regulator or governor are of no particular importance so long as the governor will function to maintain a constant delivery pressure on its outlet side. The same remark holds true with respect to the governor lever operating mechanism under the control of the thermocouple. The main consideration is that such mechanism shall enable the governor to be loaded and unloaded in accordance with the temperature requirements of the furnace.

With further reference to the mechanism 42 it may be stated that it usually contains a galvanometer and means for periodically depressing the galvanometer indicating needle in order that when the needle indicates a certain temperature in the furnace as maximum or minimum permissible temperature such electrical circuits may be established within the instrument as will permit the motor 44 to be actuated as aforesaid.

In the drawing, I have shown three inspirators or mixers and each mixer as supplying two burners. However, I wish it to be understood that such showing it to be taken as merely illustrative of the type of equipment to which the invention relates. In long continuous furnaces many inspirators and burners are required. In accordance with my invention all of the inspirators can be connected up to one supply manifold and a single governor utilized for controlling the pressure of the gas deliverable to the manifold. It will be understood that the supply main 26 constitutes a means which if uncontrolled would supply the entraining constituent of the gaseous mixture to the manifold -24 at a pressure in excess of the minimum pressure-requirement when the burners are to function at minimum capacity without back flash. 50 indicates a conventional cut-ofl' valve in the main 26.

What is claimed is In combination, a plurality of inspirators adapted to form a mixture of air and gas in proper proportions for substantially complete combustion, a supply line common to all of said inspirators, a burner individual to each inspirator, said burners requiring a minimum pressure of combustible mixture for functioning, without back firing, a diaphragm control valve located in said line, means for continuously making the pressure head on the delivery side of said valve cfminimum temperature, and mechanism actuated by the operation of the motor through said cycle to put said spring under tension 'and thereby effect a predetermined step-up in the pressure head at the delivery side of the valve, said heat responsive means being operable to restore said motor and mechanism to their original positions upon the occurrence of a predetermined maximum temperature.

In testimony whereof I afiix my si nature.

WILLIAM J. HARRI J R.

fective on one side of the diaphragm to regulate the opening of said valve, a counterbalance normally tending-to open said valve a ainst the pressure head effective on said diaphragm, the load on said counter-balance including a normally non-tensi'oned spring, a. motor, heat responsive means for effecting the operation of said motor through a definite cycle upon the occurrence of a predetermined

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