US2316273A - Heater - Google Patents

Description

April 13, 1943. L. MEYER ETAL HEATER Filed Sept. 17, 1940 L I m w i 5/ m v0 0 a mZ/fi a M 2 Patented Apr. 13, 1943 2,316,273 imArEa Ludwig Meyer and Friedrich Klein, Dessau, Getmy; vested in the Alien Property Custodian Application September 17,1940, Serial No. 357,175

In Germany July 13,1939

4 Claims. (01. 257-441) This invention relates to improvements in heaters, and refers particularly to heaters primarily intended for use on airplanes.

Heaters operated by the heat generated by an engine'are in common use, and consist usually either of air heaters, or steam or hot water heaters. Many heaters of the formertype are open to the grave objection that exhaust fumes are liable to mixwith and poison the air being heated, which is particularly dangerous in airplane installations; and heaters of the latter type are not satisfactorycn airplanes for the reason that they are liable to freeze up.

It is an object of this invention to, provide a heater of the air type wherein the pipe through which the exhaust gases flow is spaced from the chamber through which the air to be heated passes by tubes through which air also travels; and .to utilize these tubes as a. heat transfer medium between the exhaust pipe and the air chamber so that a high ratio of heat exchange is provided.

Another object of the invention is to provide such a heater centrally through which the exhaust pipe extends, and to provide anair cham her around this pipe which is spaced therefrom by an annular arrangement of tubes 'so disposed that a plurality of connected walls extend continuously around the pipe and amply protect theair chamber from contamination by exhaust ases in the event even of cracking of the pipe itself.

A further :object of the invention is to provide such a heater wherein the tubes, preferably rectangular in cross section, extend contiguous to one another parallel with the. exhaust pipe,

haust pipe preferably provided with a plurality of small indentations 20 therein to increase its radiating capacity. Spaced concentrically around the pipe is. is a second pipe 2! which forms the inner annular wall of an air chamber i2-the outer encircling wall of which is shown at [2a. Closing the ends of the heater are two annular walls 18 the margins of central openings of which are .brazed, welded or otherwise suitably secured around the exhaust pipe 19: In this instance eachwall [8 consists of two separate annular portions, the outer periphery of the inner portion being secured-tothe pipe 2i, and the outer sections I 8b being formed of flexed extremities of the outer chamber wall I2a.

' which are brazed or welded at their margins to the pipe 2|, as a safety precaution to prevent the entry of exhaust gases into the chamber i2; 2! denotes radiating fins which project part way across the chamber l2 from the pipe 2| which forms the inner wall of such chamber.

and are brazed or welded to the outer periphery of the latter, to the inner wall of the air chamber and to' one another, so that eiiicient heat transfer is obtained fromthe pipe to the cham ber,

Yet another object of the invention is to provide a heater which is light in weight, compact, efficient in operation, relatively easy tomanufacture. and easy to install.

Having thus briefly enumerated some of the obiects and advanta es of the invention, I will now proceed to describe a preferred embodiment thereof, with the aid of the accompanying drawing, in which: 1

Figure 1 illustrates a longitudinal section of the invention, and

Figure 2 is a section on the line 2-2 of Figure 1.

Referring to the drawing, is denotes an ex- A plurality of annularly arranged spacing members or tubes 22, preferably substantially rectangular in cross section, extending parallel with the exhaust pipe l9, have their adjacent walls brazed or welded to the latter, and their opposite walls similarly secured to the pipe 2| which forms the inner wall of the chamber l2. The contiguous, substantially radial sides of the tubes 22 are also welded or brazed to one another throughout their entire length, so that the tubes thus united to one another form an annular arrangement of radial walls between pipes I9 and 2| so that should'the former crack ample protection is afforded for preventing contamination of the air flowing through the chamber I2 by the exhaust gases, and at the same time the sides or radial walls of the tubes 22 constituteexcellent heat transfer means for the passage of heat from the exhaust pipe I 9 to the chamber i 2.

The tubes; 22 open at their extremities into an nular chambers 23a and -24a closed at their outer ends by the walls l8,'and projecting from these chambers and open to the outside air are pipes.

23 and 26 respectively. Connected to one exemity of the chamber I2 is an air inlet pipe 25. and projecting from its opposite extremity is a second pipe 26 through which heated air flows to a suitable register or outlet (not shown).

From the foregoing it will be clearly seen that hi h heat transfer is obtained from the exhaust p pe l9 to the air chamber I 2, mainly through the walls of the tubes 22; that the continuous annular arrangement of the connected tubes and th joints formed between them constitute additional protection against leakage of gas from the pipe I! into the chamber l2; and that the end wall construction further assists in preventing such leakage. Also that, due to the tubular construction of the heater, it is light in weight and therefore specially suited for use in airplanes.

While the preferred construction has been described and shown, it is understood that alterations and modifications may be made thereto provided the said alterations and modifications fall within the scope of the appended claims.

What we claim is:

1. A heater comprising an annular chamber having an inlet and an outlet pipe extending therefrom, an exhaust pipe projecting through the annular chamber and spaced therefrom, the chamber having annular end walls which project inwardly and are secured around the exhaust pipe, tubular spacing members annularly arranged around the exhaust pipe and welded or brazed thereto and to said chamber, said spacing members being contiguous and brazed or welded to one another to form an encircling gasproo'f joint between the exhaust pipe and chamber, said members actingas a heat transfer medium between the exhaust pipe and the chember,and radiating-fins projecting partway across the interior of the chamber from its inner wall.

2. A heater comprising the combination set ing from the compartments to permit passage of air through said members.

3. A heater compriesing an annular air chamber having an inlet pipe and an outlet pipe connected thereto, an exhaust pipe extending through said annular chamber, means directly connected to the exhaust pipe and the inner wall of the chamber spacing the exhaust pipe inwardly from the chamber comprising tub'ular spacing members of substantially rectangular cross section, the sides of contiguous members being secured to each other throughout their height to form an encirclingv gasproof wall between the exhaust pipe and the chamber and to serve as means for transferring heat from the exhaust pipe to the chamber.

4. A heater comprising an annular air chamber having an inlet pipe and an outlet pipe connected thereto, an exhaust pipe extending through said annular chamber sealed therefrom and spaced from the inner wall thereof to provide an annular intermediate chamber, and

' spacing members directly connected to the exforth in claim 1, wherein the spacing members' are substantially rectangular in cross section and terminate a short distance from both end walls thereby forming compartments into which the tubes open, and pipes open to the air extendhaust pipe and to the inner wall of the chamber constituting heat transfer means from the former to the latter, said spacing members comprising a plurality of tubes annularly arranged around the exhaust pipe and having juxtaposed flat walls connected to one another to form an encircling gas-proof wall between the exhaust pipe and the chamber.

' LUDWIG MEYER.

FRIEDRICH KLEIN.

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