US2199783A - Combustion device - Google Patents

Description

ay 1940- R. s. DE' I'LOR COMBUSTION DEVICE Filed May 4, 1956 Patented May 7, 1940 PATENT oFFicE COMBUSTION DEVICE Robert Sydney Detlor, Westmount, Quebec,

Canada Application May 4, 1936, Serial No. 77,755

7 Claims.

Ihe invention relates to combustion devices, as described in the present specification and illustrated in the accompanying drawing that forms part of the same.

The invention consists essentially in the devices set forth hereinafter for guarding the ignition flame, directing the air, regulating the gas feed, and lubricating the parts as described in detail herein and pointed out in the claims for novelty C- following the description.

The objects of the invention are to insure a constant flame from the ignition burner, as explosions have occurred through lack of air and through failure of the flame at the time it is 35;: needed. Often the flame must regu ate the supply of gas and air instantly to insure the ignition of combustible gases before they accumulate in explosive proportions. A further object is to facilitate the starting and stopping of the blower motor and to hasten the supply through thermo controls of the forced air feed and the opening and closing of the gas supply valve to the burner by the action of similar controls. These controls are rendered constantly responsive to burner conditions arid to the temperature of the gases within the combustion chamber. It is further aimed to maintain instant and free action of the moving parts through lubrication and to protect the interior of the gas supply valve against block- -;;-1age by the formation upon it of an oil film, and

in short it is intended generally to provide an ignition burner that will function at all times and keep a clear flame notwithstanding sudden excesses of heavy gases, and thereby contribute to .--1 :the safety of operation by supplying oxygen to the burner and firebox at the proper time. This is a continuation in part of an original. applicaation which has matured to Patent No. 2,086,608.

In the drawing,

Figure 1' is a cross sectional view of the furnace casing showing a plan view of the interior and the several connections for the blower and torch respectively.

Figure 2 is an horizontal sectional view of the .gas burner mounted in the furnace wall.

Figure 3 is a vertical sectional detail view of the main thermo-control.

Figure 4 is a vertical sectional view on the line ---i in Figure 3.

Figure. 5 is a vertical sectional view of the electrically operated gas supply valve and oil chamber.

Like numerals 'of reference indicate corresponding parts in the. various figures.

Referring to the drawing, the firebox of the furnace is indicated by the numeral [5 and is shown with a bed of hard fuel it on the grate over the ash pit. The blower i9 is operated by the electric motor 20 and has pipe connections 2| to the blower chamber 22 which opens through the furnace-wall 23 to the ash pit l8.

Above the level of the fuel bed it there is an ignition burner having a tubular member 24 extending into the combustion chamber from the coupling nipple 25, which is inserted through a hole in the furnace wall or door frame, and extends on either side therefrom. The tubular member 2 3 is elbowed at 2B and projects beyond the wall 23 of the furnace.

A flaring inlet casing 2'! is mounted on the outer end of the nipple 25 and has a closure cap 28 having a central screwed aperture. An inner tubular member 29 forms with the tubular member 2 an annular supplementary air passage 36 extending from the inlet casing 21 along the length of the tubular member 24.

A valve chamber 3i has the walls 32 cast in the inner end of the tubular member 2%. The walls 32 extend outwardly to contact with the inner surface of the tubular member 25, which closes the chamber, while a plug 33 in the wall of the tubular member 24 provides access to the chamberSI from the outside. A burner tip 34! is mounted in the aperture 35 in the front wall of the valve chamber 3|, while the gas supply tube 36 is mounted in the opposite wall of the chamber and extended centrally through the tube 29 and with the closure cap 37 closes the end of the tube 29. An aperture 38 in the tube 29 between the closure and the cap 31 provides a natural air inlet to the annular passage 3!: extending beyond the burner tip 34. A pipe connection lll connects the air inlet casing 2T with the blower chamber 22 while the pipe ll connects the gas sup-ply tube 36 of the burner with a source of gas supply and has a valve 52 introduced therein, which will be described in fuller detail hereinafter.

Within the chamber 3i a gas leak valve 43 is mounted on the free end of the thermo metal valve actuator 44. This actuator is secured within the chamber 3i as for insta'nce,. by thescrew pin 45. The valve 53 hasa reduced extension 46 projecting into the tube 36 and has the central bore 41 providing a leak hole from the tube 36 to the chamber 3i when the valve is closed. A needle or cleaner rod 48 projects centrally from the back of the valve 43' and slides in the burner tip 34 with the movement of the valve.

A casing 49 on the top side of the tube 24 atits inner extremity has a front opening 56 provided with a shield and houses a thermostatic switch mechanism. This thermostatic switch mechanism has thermometal contact bars carrying contacts 52 and 53 oppositely mounted parallel to the casing 49.

A bi-metallic heat conductor strip 54 is connected to the thermometal contact bar of the contact 53 and extends outwardly through the opening 56 over the mouth of the ignition burner. An adjustment screw 55 mounted in the casing 49 alters the setting of the contact 53 relative to the contact 52 while the screw 56 lock the setting of the contact 53.

Wires 5'! and 58 connect with the contacts 52 and 53 and are led through'an aperture 59 to the annular passage 30 and thence through the closure cap 28 to a main circuitGU.

This main circuit 60 is controlled by a switch 6| and is connected to the electric motor 20 and the electrically operated gas valve 42 through the contacts 52 and 53, and through other usual controlling devices as required.

The gas valve 42 is connected with the gas supply on the one side at 62 and with the pipe 4! and burner on the other side 63 and has a plunger 64 controlling the flow of gas to the burner. This plunger 64 is adapted to be lifted from its seat 65 through electro-magnetic attraction by the coil 66 which is connected with the main circuit 65 by wires 67 and 68 and operates with the opening and closing of the contacts 52 and 53, and from the other control devices 15.

A leak passage 69 is provided between the gas inlet 62 and outlet 63 past the valve 64 and is controlled by an adjustable needle valve 10 shown in dotted lines.

An annular projection H is provided on the bottom of the valve 42 having a cup or plug 72 providing a closed oil reservoir 13. From the reservoir 73a passage 74 communicates with the interior passages of the valve 42 which are thus covered with a film of oil finding its way from the reservoir. This film of oil throughout the valve prevents the deposit of gum or sediment from the gas on the working parts and passages of the valve. It also prevents blocking which would interfere with the free working of the valve, and maintains free from obstruction the bypass 59.

In the operation of this apparatus, the blower motor 25 and the gas valve 42 are connected in the main circuit 50, which is completed through the contacts 52 and 53 and the controlling devices 75. When the pilot flame is extinguished, as for instance by failure of the gas supply, the contact bar of the contact 53 is not distorted by heat conducted through the strip 54 and the contacts 52 and 53 separate, opening the circuit and thereby shutting off the blower motor 25 and closing the valve 42.

When the pilot is again lighted in any suitable manner after the gas supply is established, the strip 54 will be heated by the pilot so that the contacts close, the blower and gas valve will be brought into full operation, causing a supplementary feed of air to passup through the pipe 45 from the blower chamber 22. This flow of air envelopes and protects the increased gas flame at the burner tip 34 to give a full flaming torchv for ignition of unburnt combustible gases with-.

in the firebox above the fuel bed. The thermostat 44 is affected by the resulting increase in temperature and is distorted to close the valve 43 to prevent a large fiowof gas through into is adapted to the chamber 3| and to the burner tip 34 thus reducing the flame. When the heat of the fire is decreasing, as when the blower is stopped or fresh fuel being added, the thermostat 44 opens the valve 43 to permit a greater flow of gas through the pipe 36. This thermostat 44 thus insures economy of gas while the fire is in a safe state, and automatically provides a powerful fiame when needed.

When the blower is stopped, the plunger 64 shuts off the main supply of gas past the valve 42 and there is no supplementary air through the pipe 40, the burner is supplied with a small leak of gas through the passage 69 of the valve 42 which passes along the pipes 4| and 36, thence through the leak bore 41 of the valve 43, and with a natural draught entering the annular passage 39 through the aperture 38.

By the action of the oil finding its way from the reservoir 13, the passages including the leak passage 65 and 74 and also the plunger 64 are kept covered With a fine film of oil which prevents any blocking particularly of the small bore passages. This assures maintenance of the full fiow of gas and the easy and instant operation of opening and closing of the valve, thereby insuring the maintenance of the burner flame within the furnace at all times to cause immediate ignition of combustible gases and the prevention or explosions,

When the pilot is lighted the contacts 52 and 53 are closed and remain in this state while gas is passing through the burner. Should the flow of gas stop, heat is dissipated from the strip 54 with the result that the contact bar straightens out and the contact 53 is separated from the contact 52. This results in an open circuit, stopping the blower, and preventing the formation of large volumes of combustible gas in the furnace.

The contacts 52 and 53 keep apart irrespective of the varying temperatures of the fire, and the circuit is closed only when the bar carrying the contact 53 is distorted towards the contact 52 by heat conducted through the heat conducting strip 54 from the burner flame.

What I claim is:

1. A combustion device for furnaces comprising a gas torch extending into the firebox above the fuel bed, said gas torch having a gas supply passage, and a thermally operable valve in the gas supply passage for regulating the flow of gas to the torch in accordance with the condition of the fire.

2. A combustion device for furnaces comprising a gas torch extending into the firebox above the fuel bed, said gas torch having a burner tip, a gas supply passage leading to the burner tip, and a thermally operable valve in the gas supply passage for regulating the flow of gas to the burner tip in accordance with the condition of the fire.

3. A combustion device for furnaces comprising a gas torch extending into the firebox above the fuel bed, said torch having a burner tip, a valve chamber communicating with the burner tip, a gas supply pipe leading into the valve chamber, a valve in the chamber, and a thermostatic element adapted to move the valve towards its closed position as the temperature of the element increases and a by-pass for maintaining a small flame at the burner tip when the valve is in the closed position.

4. A combination device for furnaces comprising a blower for supplying air to the furnace, and a gas torch adapted to provide a flame in the furnace for igniting gases driven off the fuel bed by the operation of the blower, a supply pipe leading to the torch, a control valve between the torch and the gas supply pipe, said control valve being adapted to be held open when the blower is in operation to provide a large flame from the torch, the control valve having a by-pass for maintaining a pilot flame from the torch when the control valve is closed, the gas torch having a thermally operable gas valve for reducing the flame as the temperature in the furnace increases, and a thermally operable switch adapted to open when the torch is extinguished so as to render the blower inoperative.

5. A combustion device for furnaces comprising a blower, a gas torch extending into the flrebox above the fuel bed, said torch having an air passage connected to the blower, a gas supply pipe within said air passage, a valve chamber in the gas supply pipe, and a thermally operable valve in the valve chamber for controlling the flow of gas in accordance with the condition of the fire, said air passage including an inlet for supplying air to the torch when the blower is inoperative.

6. A combustion device for furnaces comprising a gas torch extending into the firebox above the fuel bed, said torch having a burner tip, an air passage and a gas supply pipe, a valve chamber connecting the gas supply pipe to the burner tip, a valve in the valve chamber, a thermostatic element in the valve chamber adapted to move the valve to reduce the flow of gas to the burner tip as the temperature of the element increases, and a cleaning rod adapted to be moved by the thermostatic element to clean the burner tip.

7. A combustion device for furnaces comprising an electrically driven blower for supplying air to the furnace, a gas torch adapted to provide a flame in the furnace for igniting gases driven off the fuel bed by the operation of the blower, the torch being supplied with gas through an electrically operable control valve, the control valve being adapted to be held open by the electric current operating the blower to provide a large flame from the torch while the blower is operating, the control valve having a by-pass for maintaininga pilot flame from the torch when the control valve is closed, the gas torch having an air passage connected to the blower and adapted to supply air to the torch flame when the blower is operating, the air passage including an air pipe adapted to supply air to the torch flame under the natural draft of the furnace when the blower is inoperative, the gas torch having a thermally operable gas valve adapted to reduce the flame as the temperature in the furnace in, creases, and a thermally operable switch'connected in circuit with the blower and the control valve and adapted to open when the torch is extinguished to render the blower inoperative.

ROBERT SYDNEY DETLOR.

Images