US1547156A - Heater - Google Patents

Description

July 21, I925. 1,547,156

A. J. LOEPSINGER HEATER Filed March 6, 1920 'IIIIII/nh 7? INVE NTOR ATTORNEYS Patented July 21, 1925.

UNITED STATES ALBERT J. LOEPSINGER, F EDGEWOOD,

RHODE ISLAND, ASSIGNOB TO GENERAL FIRE EXTINGUISHER COMPANY, OF PROVIDENCE, BHQDE ISLAND, A CORPORA- TION OF NEW YORK.

HEATER.

Application filed March 6, 1920. Serial No. 363,762.

To aZZwhom it may concern:

Be it known that I, ALBERT J. LOEPSINGER, a citizen. of the United States, residing at Edgewood, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Heaters, of which the following is a specification. This invention relates to improvements in heaters.

method and apparatus for utilizing products of combustion, or other high tempera ture gases, for special purposes, such as drying or evaporating, or for general heating, where the direct application of the high temperature to the heating or radiating apparatus is objectionable. For industrial uses requiring radiation from temperatures higher than those safely or easily attained with steam, the gaseous products which come from combustion of gas, oil or other fuel offer advantages of convenience and of economy. As compared with use of heated oil as a distributing medium, for example, they avoid losses sustained in transferring the heat from one medium to another, and

also avoid the danger of the pipes becoming clogged by carbonization, and the hazard of escape of the hot liquid. The initial temperature of products of combustion is so high, however, that there has been no known way, so far as I am aware, to produce a reasonably uniform heat therefrom through any considerable length of piping. Attempts to overcome. this objection by mixing a cooler gaseous medium with the products of combustion are unsatisfactory, one reason being that this promptly reduces the high temperature which it is desired to maintain. The present invention relates particularly to a method and apparatus for maintaining high temperature of the products of combustion, for a considerable distance through thepipe, the loss of heat therefrom being but slow, accompanied, however, by a moderate temperature oft'he pipe itself, predetermined, as high as desired, and having the notable characteristic of approximate uniformity throughout th pipe length. The invention provides a process and apparatus by which these gases, and even the flame, pass into a pipe which has no part overheated by them. This is accomplish by providing a More particularly it relates to a tubular container, preferably an ordinary iron pipe such as is used in radiators, into which the highly heated gases are introduced in such manner that they are kept from direct contact with the metal of the pipe, being separated by a difierentially moving, and preferably a more rapidly moving, envelope or film of a cooler medium, such as air, which acts as aneat insulator or retardant. The envelope maintains its position next the wall of the pipe, seemingly by virtue of the momentum and direc tion of particles moving therein, and keeps itself separate from the core of highly heated gases without mixture, for thesame causes. It can be imagined that a particle of the latter, essaying to'enter the envelope by expansion, after the manner of a gas, which entry if effected would result in a mixture being made, finds itself promptly knocked back, as it were, by encountering some one or more swiftly moving particles in the envelope before it has time to penetrate between said particles as it might do if the envelope were moving with equal speed with it. The air envelope being put in through an annular nozzle surrounding the place where the heat carrying gases enter, the exterior temperature of the pipe is found to approximate uniformity for a considerable distance. For practical purposes, it is customary to build head radiation coils of successive lengths of straight pipes joined by return bends. In such cases, it is sometimes desirable to install at the bend a fitting which has an annular nozzle to form afresh the inslulating envelope by the entrance of mor air on account of the envelope that protected the previous length having become more or less broken up by partial mixture with the heated gases at the return bend.

No particular gas to constitute the envelope, and no particular speed, appear necessary to successful operation; but it is generally most convenient and best to use air for the envelope and to move it much faster than the heated contents which it surrounds. The heat carrying gas that is to be thus insulated from the pipe in such manner as to act as a reservoir of heat, and to part with its heat only slowly, does not necessarily originate from combustion, nor, if it does, need it proceed immediatelyfrom the flame into the pipe. The entering envelope tends to have an injector action, as is particularly observable in case the flame projects into the tube, when it can be seen drawn out in bottle neck style. A suction fan may be used at the discharge end to draw the flame and the gaseous envelope together through the tube, this being useful in the case of an unusually long coil. The invention may obviously be applied in many ways, and with various apparatus. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty exist in the apparatus and method or process herein disclosed.

The accompanying drawing illustrates an embodiment of apparatus and a method of practicing the invention, the single figure being a representation in elevation, in medial section, of fragments of a coil of pip ng.

Referring to the drawing: 10 indicates a stretch of pipe which may be, for example, ten or twelve feet long, at the beginning of which is a cast iron fitting 11 having an axial funnel 12 through Which the products of combustion of a flame 13 may enter, while around this funnel 12 is an annular nozzle 14 discharging from an annular chamber 15 to which air or other relatively cool medium is supplied through a pipe 16 and valve 17 under pressure which may, for example, be five or six pounds per square inch. At the further end of the pipe 10, or at the end of some subsequent length of pipe, where there is to be a deflection of the course of the heated gases is a fitting 21 which, as illustrated, makes 180 turn, called a return bend from the pipe 10 at its full diameter and reduces into a funnel 22 around which is a chamber 25 and annular nozzle 24 for a fresh supply of enveloping air under pressure, both of which lead into a length of pipe 20 parallel to the length 10. Air is supplied to the chamber 25 through a pipe 26 and valve 27 which may in all respects be duplicates of the pipe and valve 16 and 17, and may discharge air at the same pressure. A continuation of this arrangement as far as desired, with repeated pipe lengths and deflecting and reenveloping fittings, complete the heater, the contents of which are finally discharged as may be desired.

In apparatus thus constituted, it has been found that, working with a gas flame from a 1" Meeker burner, operating in atmos phere and with a pressure of air for the annular nozzle of five or six pounds per square inch, and with a 2 pipe and with dimensions of fittings approximately as illustrated, the pipe temperature approximates uniformity throughout its whole straightaway length which is conveniently twelve feet or so. This is true whether the pipe be vertical, or be horizontal, which is generally preferable. Without the method and apparatus thus described the iron piping gets red hot near the burner, while with it the temperature may be, for example, about 200throughout its length. This condition of uniform temperature will continue around deflections and bends, but not so perfectly. Return bends may be used according to needs and preferences, either of the ordinary simple style, or bends involving the re-application of the method set forth, as shown in the upper part of the drawing. Obviously if it were desired such envelope re-establishing nozzles could be in serted in a long straight length.

lVith such apparatus, the total heat of the combustion may be maintained as in an at tenuated reservoir, from which it gradually escapes at a moderate and useful tempera-- ture. The heat is carried in the central current, comprising products of combustion and such air as may become mingled therewith from time to time from the moving envelope. It probably passes thence through the envelope by a process akin to radiation, or, if it be by convection, it is only by convection resulting from movement of particles of .the enveloping medium within the mass of such particles which constitute the envelope. In either event it passes but slowly, and the envelope acts as an insulator or retardant conserving the heat of the medium which it surrounds. Conduction and radiation, which proceed promptly of all heat that reaches the iron wall of the pipe, keep down the temperature of the envelope. Mean while, the envelope itself does not accumulate heat excessively for it is continually moving on, and that which has become heated to the predetermined degree ultimately removes itself. As the temperature of the movable screen in the middle of the pipe gradually diminishes, the later stages of the envelope may be thinner; and the piping and fittings may be designed with this in mind.

Although the best results are attained with the envelope definitely surpassing the central current in velocity, experiment has shown that there is some benefit in having the air introduced at a slower speed than the speed of said heated products of combustion.

I claim as my invention 1. In the art of heating, the introduction into a conduit of a stream of highly heated gases accompanied by the introduction of an envelope of cooler gases, the gases in said stream and envelope flowing substantially unmixed within the conduit whereby a high temperature of said heated gases is maintained to a distance in the conduit.

2. In the art of heating, the provision of a stream of highly heated gases and the surrounding of it with an envelope of cooler gases moving parallel to it and more rapidly than it, whereby said heated gases are maintained segregated in a stream for a considerable distance, within the said envelope, thereby maintaining a high temperature.

3. A method of retarding distribution of heat from gases, comprising the formation of the heated gases in a stream; the formation of an envelope of cooler gases sur rounding them, and moving more rapidly, and the constraining of the said envelope against lateral outward expansion, by sur rounding it with a solid wall, as a pipe, whereby the diffusion of particles of the said heated gases toward the pipe, with consequent loss of heat thereto, is retarded.

4. In the art of heating, the introduction to a conduit, having heat conducting and radiating walls, of a stream of heated gases and the co-incident projection into the conduit, by a source of energy independent of the said stream, of an annular stream of cooler gases moving more rapidly than and surrounding the first mentioned stream.

5. The art of transmitting a highly heated gases medium through a conduit with but slow and gradual loss of heat en route, comprising the introduction and segregation of said medium in the middle of the conduit; the introduction and segregation of a hollow stream of cooler gases movlng through the conduit between it and said medium, the said medium being at its core; and the maintaining of said streams respectively, the one as a core stream and the other as the walls of a tubular container of the core stream, substantially without diffusion of gases of the core stream into the gases of the hollow stream around it.

6. The art of maintaining a radiating surface at approximated uniformity of temperature, with heat supplied from a cloosely adjacent highly heated gaseous medium, comprising the provision of an intervening cooler gaseous medium, and the placing of both mediums in motion parallel to the said surface, the cooler moving the more rapidly.

7. In the art of heating, the passing of a stream of heated gases through a heat radiating conduit, and the introduction there to at intervals of annular streams of cooler gases each in turn surrounding and moving forward more rapidly than the contents of the conduit at the place where it is introduced, whereby uniformity of radiating temperature along the length of the conduit is approximated.

8. In the art of heating, the passing of a stream of heated gases through a heat radiating conduit having successive sharp deflections of direction and the introduction thereto at places where a deflection has occurred of annular streams of cooler gases each in turn surrounding the contents of the conduit at the place where it is introduced, whereby uniformity of radiating temperature along the length of the conduit is approximated.

9. method for approximating uniformity of temperature in the walls of a tu bular conductor of heated gases, in which the said gases are directed and maintained in a central stream within the conduit and a cooler gaseous medium is introduced as a tubular stream at higher velocity between the said central stream and the conduit walls, and keeps the gases of the central stream from direct contact with the walls.

10. Heating apparatus comprising a conduit of heat radiating material; means for introducing highly heated gases to the central portion of said conduit with velocity in the direction of the length thereof; and means whereby an envelope of cooler gases is simultaneously introduced into the conduit around said heated gases with greater velocity in the same direction; whereby the said heated gases and cooler envelope move parallel to each other as substantially separate bodies through the conduit and the high temperature gases are prevented from making direct contact with the conduit.

11. Heating apparatus for containing highly heated gases, comprising a tubular conduit; an axial funnel through which the I said gases may enter; an annular nozzle around said funnel through which cooler gases may enter, and suitable sources of energy for forcing in the said heated gases at lower velocity and cooler gases at higher velocity the said funnel and nozzle being arranged to produce an envelope of said cooler gases around the heated gases and thereby to prevent contact of the latter with the walls of the conduit.

12. Heating apparatus comprising a heat radiating conduit having sharp deflections of direction and adapted for containing a stream of high heated gases, said conduit being tubular and having a funnel at its entrance end through which the heated gases may enter, an. annular nozzle around said funnel for introduction of cooler gases to form an envelope in said conduit around said heated gases, and a funnel beyond each sharp deflection of the conduit, through which the stream and envelope may pass together, with an annular nozzle for the introduction of additional cooler gases to form a fresh envelope.

Signed at Boston, Massachusetts, this fourth day of March, 1920.

ALBERT J. LOEPSINGER.

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