US2404646A - Heater - Google Patents

Description

July 239 1946. H. J. DE N. MccoLLUM 2,404,546

HEATER Filed Feb.` 18., 1943 Patented July 23, 1946 HEATER Henry J. De N. McCollum, Chicago, Ill.; Thelma McCollum executrix of said Henry J. De N. Mc-

Gollum, deceased Application February 18, 1943, Serial No. 476,266

11 Claims. l

My invention relates to heaters and more particularly to heaters of the internal combustion type.

An object of my invention is to provide an internal combustion type of heater having improved means for obtaining thorough vaporization of the liquid fuel.

Another object of my invention is to provide new and improved means for imparting any desirecl degree of preheating to the combustible mixture.

Another object of my invention is to provide a new and improved heater wherein the foregoing objects are accomplished by a structure which is compact, light in weight, inexpensive to manufacture, and troublefree in use.

Other objects and advantages will become apparent as the description proceeds.

In the drawing:

Fig. 1 is a longitudinal, sectiona1 view of a preferred form of heater embodying one form of my invention; and

Fig. 2 is a partial, transverse section taken on the line 2--2 of Fig. 1.

In Figs. l and 2, I have illustrated a preferred form of my invention comprising a heater having an air inlet Iii adapted to be supplied with air from a ram, blower, or any other suitable source of air supply. A part of the air entering the inlet il) passes into a Venturi tube I2, having a fuel jet I4 provided with radial passages I 6 in the throat of the Venturi tube. The jet I4 is supplied with any suitable liquid fuel, such, for example, as gasoline or kerosene from any suitable source of fuel supply and the fuel discharged from the passages l 6 in the jet I4 mixes with the air entering the lefthand or inlet end of the Venturi tube l2 to form a combustible mixture.

This mixture passes from the outlet or righthand end of the Venturi tube I2, through a wire Iscreen i8 into the fibrous material 2B contained in a sheet metal cannister 22 having an opening 24 in registry with the outlet end of the Venturi tube i2. less steel wool or glass wool, or a mixture of stainless steel wool and glass wool, or any other suit able material.

As the combustible mixture passes `through the fibrous material, the fuel and air are thoroughly mixed and may be preheated to any desired degrees, as hereinafter explained. The combustible mixture flows through the outlet openings 2B in the righthand end of the cannister 22 and passes into a combustion chamber 23 where it is initially ignited by an electrical igniter 30, or any other The fibrous material 20 may be stainsuitable means. The igniter 3B, in accordance with usual practice, may be disconnected from its source of current by a ,thermostatic switch after the heater attains normal operating temperature and I provide a re-igniter 32 to maintain combustion after the igniter 3E] has been cut out.

IThe hot gases resulting from the combustion in the combustion chamber iiow into the righthand ends of the longitudinally extending flues 34 formed in a cylindrical heat exchanger indicated generally by reference character 36 and pass from the lefthand end of these iiues into an outlet chamber 38. An outlet tting 4D is xed in a wall of the chamber 38 and has a threaded end 42 to which any suitable exhaust pipe may be connected whereby the cooled gases may be discharged from the outlet chamber 38 through t` ting llt and the exhaust pipe connected thereto.

The heat exchanger 36 comprises a corrugated `sheet 44 of aluminum orother suitable material bent into the form of a cylinder and having its contacting edges Welded to form a seamlessl tube. Fins 46 of aluminum or other suitable material are welded or otherwise secured in the folds 48 formed in the aluminum sheet 44 between the ues 34. The fins 46 are in the form of sheet metal 'strips having their outer edges serrated, as indicated at 5E, to divide the radially outward portions of the strips 46 into a plurality of fingers 52 to increase the rate of heat transfer from the fins to Ventilating air directed thereover in a manner hereinafter described.

A tubular muffler 54 is located inside of the aluminum sheet 44. This muffler comprises an outer shell 56 and sound absorbing material 58, 'such as stainless steel wool or glass wool, located between the shell 55 and the sheet metal cannister 22 which forms the inner wall of the muffler. The shell 5B is provided with openings 6i! which form acoustic couplings between the interior of the shell 56 and the iues 3Q, whereby sound may enter the shell 5t and be absorbed by the mate* rial therein. While the muffler proper consists of only a relatively thin layer of sound absorbing material arranged in the form of a tube, I have found that such a thin layer absorbs all of the objectionable sound and is entirely satisfactory.

The heater is provided with a cylindrical casing 62 which Isurrounds the heat exchanger 36 and directs Ventilating air thereover. The lefthand end of the cylindrical casing 62 communicates with the inlet I0 by way of tapered passage 64 formed between an outer sheet metal cone 66 and an inner sheet metal cone 68. The righthand end of the casing 62 may communicate directly with the airplane cabin or other space to be heated, or may be connected to a duct system having several outlets placed at selected locan tions to distribute the heated Ventilating air to several portions of the same space or to separate spaces.

The ends of the aluminum sheet Mi of the heat exchanger 3s are illustrated as being located in grooves formed in rings 'ill and '12, which form a convenientl means for supporting this plate and associated parts. The ends of the plate is are sealed to the rings lul and l2 by welding, or otherwise, to prevent leakage of the products of combustion into the passageways'for the ventilating air The ring It is attached to and supported by the cone S8, whereas the ring 12 is attached to and supported by the end wall 'i4 of the combustion chamber 28.

Stainless steel wool is a relatively good heat conductor, whereas glass wool is a relatively poor heat conductor. When a heavy fuel is used, or when, for any other reason, a relatively great amount of preheating is desired, the muliler shell 55 and cannister V22; can be lled with stainless steelV wool'. On'the other hand, when substantially no preheating is desired, the muler shell and cannister can be lled with glass wool. When some intermediate degree of preheating is sought, part of the space inthe muliler and cannister can be filled with stainless steel wool and the other part With glass Wool and in this marlner any desired degree of preheating can be obtained. n Y

' In my invention the combustible mixture formed in the carburetor is rst passed through fibrous material which insuresk vaporization of all ofthe liquid fuel and thorough mixing of the vaporized fuel and air before this` combustible mixture enters the combustion chamber. In my invention the fibrous material is exposed to heat created in the burner and by proper selection of the particular 1ind or kinds of fibrous material Used, any desired degree of preheating of the combustible mixture may be provided. These featuresr render my novel heater particularly adapted for use with different fuels` such, for exampla as gasoline, lsercseneand fuel oil, since these fuels require different degrees of pre.-

heating to burn efficiently. The length of the fibrous pathrthrough which. the combustible mix? ture flows before entering the combustible cham-` ber can also be varied to afford just the right amount of preheating, vaporizaton and intermixing of the fuel and air before thisl fuel enters the combustion chamber to adapt the heater to any particular fuel or to satisfy special operating conditions.

The foregoing advantages are attained in a structure which is compact, light, inexpensiveto manufacture and which requires a minimum of service attention, This heater is particularly adapted for use in aircraft, but is notlimited to such use and capable of general application.

While I have described only one embodiment of my invention, it is Ito be understood that my invention is not limited to the particular details shown and described, but may assume numerous forms and that., the scope of my inventionV is defined in the following claims.

I Claim:

l, A heater comprising a combustioncliamber, a heat exchanger communicating with. said combustion chamber and heated byproducts ofV combustion therefrom, means for supplying a combvstible mixture to said combustion chamber, said means including a Venturi tube, and means forming a passage through said heat exchanger filled with brous material interposed between said combustion chamber and said Venturi tube and through which the combustible mixture must pass before entering the combustion cham-Y ber, part of said fibrous material being located immediately adjacent the end of said Venturi tube.

2. A heater comprising a combustion chamber, a heat exchanger receiving products of combus-` tion from said combustion chamber, means for directing Ventilating air over said heat exchanger, a carburetor for supplying combustible mixture to said combustion chamber, means forming a passage through said heat exchanger interposed between said carburetor and said combustion chamber, and steel wool in said passage for preheating, vaporizing and intermixing the fuel and air in said lcombustible mixture prior to the entry of this mixture into the combustion chamber.

3. In a'heater of the class described, the combination of a heat exchanger, a combustion chamber located at one end thereof, a carburetor located at the other end of said heat exchanger, fibrous material interposed between said carburetor and combusti-on chamber in heat exchange relation with said heat exchanger and through which combustible mixture supplied by said carburetor must pass before entering such combustion chamber, said fibrous material pre#` heating, vaporizing and intermixing the fuel and air in the combustible mixture prior to its entry into said combustion chamber, and Ymeans for directing Ventilating air over said heat exchanger, Y

e. A heater of the class described, comprising a tubular heat exchanger, a casing enclosing said heat exchanger, said casing having an inlet for Ventilating air adjacent one end of said heat exchanger, a. carburetor at said end of theV heat :exchanger and receivingair from said inlet, a comy bustion chamber at the opposite end of said heat exchanger for supplying products of combustion thereto, means forming a passage located in said heat exchanger and` affording communication between said carburetor and combustion chamber, fibrous mat rial located in said passage, a muiiler interposed between said passage and said heat exchanger, and an exhaust chamber surrounding said carburetor and receiving products of combustion from said heat exchanger.

5. A heater of the class described, comprising a tubular heat exchanger, a combustion chamber for supplying hot products of combustion to said heat exchanger, a muier located in said heat exchanger, said muliler comprising inner and outer tubular shells forming a space therebetween filled with sound absorbing material, and means for supplying a combustible mixture to said combustion chamber through the tubular inner shell of said muiiler.

6. A heater comprising a combustion chamber, a heat exchanger receiving products of combustion from said combustion chamber, means for the fuel and air in said combustible mixture prior to the entry of this mixture into the combustion chamber.

7. A heater of the class described, comprising a heat exchanger, a combustion chamber for supplying products of combustion to said heat exchanger, a muffler located in said heat exchanger, stainless steel wool in said muilier, said muiller having means forming a passage therethrough, means for supplying a combustible mixture to said combustion chamber through said passage, and steel wool located in said passage.

8. In a heater of the class described, the combination of a heat exchanger, a combustion chamber for supplying hot products of combustion to said heat exchanger, a tubular mufller 1ocated in said heat exchanger, means for supplying a combustible mixture to said combustion chamber through said muflier including fibrous material within said muler through which said combustible mixture passes as it travels the length of said muiiler.

9. A heater of the class described, comprising a heat exchanger, meansfor directing ventilating air over said heat exchanger, a combustion chamber for supplying hot gases to said heat exchanger, a carburetor for supplying combustible mixture to said combustion chamber, means interposed between said carburetor and combustion chamber and forming a passage therebetween and through said heat exchanger, said means having a plurality of openings connecting said passage with said combustion chamber, 1ibrous material located in said passage, and a metal screen interposed between said carburetor and said passage. Y

10. A heater comprising a heat exchanger, a combustion chamber for supplying hot gases to said heat exchanger, a muffler in said heat exchanger, means for supplying combustible mixture to said combustion chamber, means forming a passage through said muffler connecting said means with said combustion chamber, said passage and muler providing separate spaces, fibrous material in said spaces and comprising stainless steel wool in one of said spaces and glass wool in the other of said spaces to proportion the amount of preheating of the combustible mixture. Y

l1. A heater of the class described, comprising a tubular heat exchanger, va combustion chamber for supplying hot gases to said heat exchanger, and a muffler in said heat exchanger, said mufler comprising inner and outer tubular shells affording an annular space therebetween which is radially narrow as compared to the radius of said'outer shell, sound absorbing material between said shells, and means for supplying a combustible mixture to said combustion chamber through said inner tubular shell, said combustible mixture being preheated as it passes therethrough.

HENRY J. DE N. MCC'OLLUM.

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