US2578520A - Method and apparatus for heating by the laminar combustion of gas in the interior of dull radiation tubes - Google Patents

Description

11, 1951 4 R. DUCHENE 8, 20

METHOD AND APPARATUS FOR HEATING BY THE LAMINAR COMBUSTION OF GAS IN THE INTERIOR 0F DULL RADIATION TUBES Filed June 21, 1947 III]! INVENTOR. Ross/2 DucHA E A TTdfP/VE) Patented Dec. ,11, 1951 METHOD AND APPARATUS. FOR HEATING BY THE LAMINAR COMBUSTION OF GAS IN THE INTERIOR OF DULL RADIATION TUBES Roger Duchne, Paris, France, assignor to Gaz de France, Ex Compagnie du Gaz de Paris, Paris,

France Application June 21, 1947, Serial No. 756,176 In France February 8, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires February 8, 1965 This invention relates to an apparatus for the high-output gas heating of a confined or enclosed space of any kind, by the emission of infra-red rays, Without there being direct contactbetween the flam or the products of combustion and the atmosphere of the enclosed space. The device fr-the emission of the rays comprises. metallic tubes or other tubes such as refractory tubes, the external surface of which is maintained at a temperature of about 300-4=O0 Q, by a progressive combustion of gas in the tubes with a very soft and long flame. Such a flame is obtained by allowing the gas or a mixture of previously mixed gas and air to flow inside a horizontally mounted tube, along its upper surface in order to establish in the tube, by diiie-rence of density, a plane of separation between gas and air;

' This result is obtained while feeding of the gas under a very weak pressure amounting to only a few millimeters of water.

The proposed device for carrying out the invention comprises one or more similar units each unit including a dull-radiation heating tube, a burner for feeding the gas at the entrance of the heating tube and an outlet for the burned gas, or a suitable combination of tubes and burners, the units being associated with reflectors formed from polished metal.

The metallic heating tube comprises either a single horizontal tube or a, horizontal tube connected to another horizontal tube extending in another direction, for example either in the horizontal plane or in the vertical plane. The change in direction of the tube may amount to 180, that is to say, the tube can be bent back in hairpin form. The combustible gas and the air for combustion enter the tube at the mouth, while at the other end the products of combustion are evacuated towards the flue. The material forming the tubular element should possess a high emissive power. Such is the case in connection with oxidized iron or cast metal, but any other metal or material having a relatively high emissive power is suitable.

The burner, which must emit a jet of gas flowing in the tube in laminar form under the effect of the draft, does not comprise an injector as in ordinary burners, but is formed by a simple tubular element of large cross-section occupying a portion of the cross-section of the tube. The air necessary for combustion enters the tube parallel to the jet of gas and flows evenly in laminar flow under the effect of the draft.

This method of feeding the gas and the air 4 Claims. (Cl. 12691) limits the permissible delivery with respect to a.

given tube according to the cross-section and the length thereof and also according to the drop in pressure produced at its outlet. Thus, whenthe gas is ignited, there is established along the upper.

surface of the tube a very elongated flame, the appearance of which evokes the regular flow, Without swirl, of a fluid on fire. To obtain this result the. delivery of the burner must be reg,- ulate to the cross-section of the tube and according to the drop in pressure maintained at its outlet.

The invention is applicable to a large. number of industrial and domestic uses. Among the in dustrial applications, there may be mentioned the heating of bakers or biscuit-makers ovens, with continuous or intermittent introduction into and withdrawal from the oven, pastry-makers ovens, meat-curing ovens, various drying apparatus. for example for the drying of lacquers on metal, the drying of coatings or emulsions on paper, cardboard, etc., the drying of linen, rags, etc. Among the domestic applications, there may be mentioned, for example, radiators for heating apartments or offices, and kitchen ovens.

In order that the invention may be more clearly understood one embodiment of the invention will be described by way of example, with reference to the accompanying drawing in which:

Fig. 1 is a front elevational View of an apartment radiator.

Fig. 2 is a, plan of Figure 1.

Fig. 3 is an end elevation.

Fig. 4 is a section through the mouth of the heating tube taken along the line AB, of Fig. 5, and

Fig. 5 is a cross-section of the burner along the line CD in Fig. 4.

The radiator illustrated in the drawing comprises a single metallic heating tube I open at both ends and wound back upon itself several times in s-form in the vertical plane. The metal forming this tube possesses a highemissive power, and is, for example, iron or cast metal. The mouth 2 of the tube at one end of the lower branch receives the burner 3, while the outlet 4 at the end of the upper branch forms the discharge pipe for the products of combustion.

The burner 3 is arranged for the accomplishment of a laminar flow at the mouth 2 of the heating tube and along the upper surface of the tube, so that, when the gas is ignited, there is effected combustion in sheet form without swirl,

at least along the entire length of the upper surface of the first branch of the heating tube.

With this object in view the burner possesses a cross-section in the form of a segment of a circle, as shown in Fig. 5.

A shaped reflector of polished metal is placed behind the tube, on the one hand to suppress radiation towards the rear and on the other hand to distribute the radiation evenly in the region of use, in such a way that the radiated heat reaches, from head to foot, a man standing upright 2 meters away from the apparatus.

The delivery of the gas is regulated either by a pressure regulator, if the distribution of the gas is carried out at a substantially constant pressure, or by a delivery-limiting means 6, if the pressure of the system is subject to very great variations. This delivery-limiting means can be arranged, for example, to permit correct feeding in two very different pressure-distribution ranges.

From the outlet 4 there can be branched an air-admission conduit 7 forming a draft control, and the action of this draft control is made adjustable by a valve 8.

There is shown at 9 a tap controlling the feed and at 10 a by-pass capable of remaining ignited when the burner is extinguished and permitting the relighting of the latter after the re-opening of the tap 9.

In order to increase the heat exchange between the flame and the tube and to obtain a more stable flame, there is advantageously provided in the part of the tube where combustion occurs, an internal longitudinal rib or partition secured to the upper surface of the tube and extending inwardly into the tube for a distance of a few millimeters.

I claim:

1. A radiant heating device comprising an elongated horizontal tubular member having a comparatively high heat radiating characteristic and having an inlet end and an outlet end, means for supplying a low pressure gaseous fuel of a lighter density than air; and a gas burner connection with said gas supply means having a nozzle of a cross-section substantially corresponding in shape and size to the cross-section of the upper portion of said tubular member, disposed within said inlet end immediately adjacent the top portion thereof, the remainder of the inlet end not occupied by said burner being open to admit air, said air being drawn into the tubular member solely by the natural draft suction created therein, a laminar division between combustible gas and air being obtained, resulting from their density differences, whereby a smooth and non-turbulent flame is formed the entire length of said tubular member along the inside surface thereof.

2. A device according to claim 1, wherein said tubular member consists of cast metal.

3. A device according to claim 1, wherein said nozzle comprises a cross section having the form of a segment of the circle forming the cross section of the tubular member.

4. A device according to claim 1 wherein there is provided on the upper surface of the tubular member an internal rib to increase the thermic exchange between the flame and the tubular member and to obtain a more stable flame.

ROGER DUCHENE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,069,867 Doherty Aug. 12, 1913 2,047,471 Hepburn et a1 July 14, 1936 2,322,341 Booth June 22, 1943 2,369,236 Jaros Feb. 13, 1945 2,398,611 Beggs Apr. 16, 1946 2,431,753 Holderle et a1. Dec. 2, 1947 2,439,038 Cartter Apr. 6, 1948

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