US2175307A - Electric heater - Google Patents

Description

Oct. 10, 1939. E. .1. PECK 2,175,307

ELECTRIC HEATER Filed March 3, 1939 2 Sheets-Sheet 1 @mmm iiorr/eqs Oct. 10, 1939. E J, c 2,175,307

ELECTR IC HEATER Jivuenior i 2 [/we// J Peck,

442 Zorvg,

Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE Application March 3,

7 Claims.

This invention relates to heat transfer means wherein the heat initiates from an electrically energized unit. A primary object of the invention is to provide such transfer means in a form that will promote the greatest possible transfer of heat to the medium being heated with a high degree of efficiency and at the same time permit the use of a very simple and relatively inexpensive construction.

It is intended that the invention find practical application throughout a wide range of uses such as in a portable radiator, water heaters, baking ovens, drying kilns, and in stationary furnaces such as the type employed for heating dwellings and the like.

The foregoing and many other objects and advantages of the. invention will become apparent to those versed in the art in the following description of the invention as illustrated diagrammatically in the accompanying drawings, in which Fig. 1 is a vertical section through a unit adapted for heating a gaseous medium; and

Fig. 2, a similar vertical section of the unit modified somewhat for heat transfer to a liquid medium.

Like characters of reference indicate like parts in the two views of the drawings.

Referring first to that form shown in Fig. 1, a chamber I0 is formed by a cylindrical wall H having an upper enclosure such as the dome l2. Within this chamber I0 is mounted a receptacle l3 built to retain oil, preferably refined petroleum. This receptacle, as indicated, is formed to have a plurality of upper and lower transversely disposed baffles l4 and I5 respectively forming a tortuous passage through the vessel from one end to the other.

. Within the vessel [3 is carried an electrical heating element [6 of any suitable type and of ample capacity for heating the oil content of the receptacle. The element I6 is carried from one end of the receptacle l3 to the other under and over the various baiiles. While the element may take a number of forms, it is herein shown as being that type wherein there is a resistance wire enclosed within a tube so as to prevent any accumulation of matter directly upon the wire itself.

Oil discharges from the receptacle I3 into a pipe I1, herein shown as connecting with an end of the receptacle near its floor. Oil is pulled from the receptacle by a pump I8 which discharges through the pipe I9 into an ascending series of coils 20 carried within the chamber I0 1939, Serial No. 259,531

close to but spaced from the Wall II. From the upper end of these coils is carried a return pipe 2! which leads downwardly to discharge into the receptacle 13 at an end removed from the outlet, herein shown as discharging through the top wall of the receptacle l3. The oil is forced upwardly through the various coils by the pump [8 so that a continuous flow is maintained by means of the pump [8. The oil is heated to the desired temperature as it flows around the various baffles by means of the electric heating element.

An interior chamber 22 is formed by a cylindrical wall to be completely open across its lower end and to merge by its upper end into an air intake conduit 23, this conduit extending on upwardly centrally through the dome 12.

The dome II has one or more air discharge conduits 24 leading therefrom, herein shown as consisting initially of thimbles telescoped over annular flanges protruding around openings formed in the dome I2. The wall II and its top enclosing dome l2 are completely surrounded by insulating material 25 of suitable type, quality and thickness as will prevent any material escape of heat by radiation from the wall H and the dome 12. In order to hold the insulation in place, an outer cylindrical wall 26 is employed to have the upper end terminate in an enclosing dome 21. It is to be noted that the thimbles 24 extend on through the insulating material 25 to fit into openings in the dome 21 and to receive therearound the final air conducting conduits.

The air intake conduit 23 extends on through the dome 2'! to any suitable intake source.

Iii operation of this form of the invention as illustrated in Fig. 1, current is supplied to energize the heating element Hi from any suitable source through the cable 25 to heat up the oil in the receptacle [3. The pump [3 is set in operation to pull the heated oil out of the receptacle I3 and force it upwardly through the coils 20 Where the heat is transferred to the flow of air traveling across those coils. The oil loses its heat as it travels upwardly through these coils so that cooler oil is being returned through the pipe 2| into the receptacle for further heating. When the air within the chamber If) and outside of the chamber 22 is thus heated, it tends to rise and flow out of the conduits 28. This employment then induces a down draft through the conduit 23 into the chamber 22. It is to be noted that this incoming air is allowed to expand and thus reduce its velocity after it leaves the conduit 23. The wall of the chamber 22 is in rather close proximity to the inner sides of the various coils 28 and thereby becomes heated by radiation from those coils.

The air in the chamber takes up some of this heat from the chamber wall 22 and is pulled downwardly out of the lower end of the chamber 22 to reverse its travel, as indicated by the arrow. The air thus preliminarily warmed in the chamber 22 is carried upwardly to strike the hottest coils 2i] first and on past and around all of the coils until it reaches the upper end of the chamher where it discharges outwardly through the thimbles 24 and conduits 28.

Referring now to that form of the invention as illustrated in Fig. 2, the same receptacle l3 with its bailles i4 and i5 and heating element i6 is mounted in the lower end of a cylindrical chamber 39 carrying the radiating coils 2B. The chamber 38 is surrounded by a wall of insulation 3i enclosed within a metallic wall 32. Within the coils 2t} is mounted a liquid containing tank 33 closed entirely across its floor and having an outlet pipe 3&- at its top end. This tank 33 carries an inner cylindrical shell 3'! sustained therein by any suitable means, such as by an intake pipe 35, to have the cylindrical wall spaced from the wall of the tank 33. This shell 37 is open at its lower end to permit flow of fluid outwardly therefrom into the tank 33. An external inlet pipe 36 is carried through the insulation enclosing wall to connect with the pipe 35.

In this form of Fig. 2, the heat radiated from the oil through the coils 20 heats up the space left within the chamber 39 and particularly heats the wall of the tank 33. Fluid entering the pipe 36 flows through the pipe 35 directly into the shell 3'! and there diffuses into a larger volume of fluid, which volume may have its external part at least heated to some extent by contact with the wall of the shell. The fluid is pulled from the lower end. of the shell 3"! upon discharge of fluid from the tank 33 through the pipe 34, it being assumed that there is pressure applied on medium entering the pipe 36. Thus it is to be seen that the fluid leaving the shell 31 must reverse itself and travel upwardly through the relatively narrow annular passageway left between the shell 3i and the wall of the tank 33, this wall of the tank 33, it being remembered, being the one that is receiving heat by radiation directly from the coils 2t. It is to be observed that the fluid entering the shell 37 has its velocity reduced by reason of the large volume of the shell in comparison to the inlet pipe 35 and that the fluid within this shell is tempered or heated by heat radiating from the heated fluid lying outside of the shell and within the wall of the tank 33. A storage space for hot fluid is left in the upper end of the tank 33 above the top of the shell 31.

While I have herein shown and described my invention in the best form as now known to me, it is obvious that structural variations may be employed Without departing from the spirit of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil traveling through the receptacle during said circulation, a chamber heated by the heat radi' ator and a second chamber within the first through which a heat circulating fluid is passed, expanded, preheated and discharged to the first chamber.

2. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil travelling through the receptacle during said circulation, a chamber, and said radiator consisting of a coiled pipe extending around the chamber in proximity to its wall and a fluid chamber within the first chamber having an inlet at its upper end and a much larger outlet into the first chamber at its lower end.

3. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil travelling through the receptacle during said circulation, a chamber, and said radiator consisting of a coiled pipe extending around the chamber in proximity to its wall, said receptacle being located in and at the bottom of said chamher.

4. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil travelling through the receptacle during said circulation, a chamber, and said radiator consisting of a coiled pipe extending around the chamber in proximity to its wall, and a second chamber located within the first chamber having a fiuid inlet at its top and a fluid discharge opening at its bottom into said first chamber, and discharge means at the top of the first chamber.

5. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil travelling through the receptacle during said circulation, a chamber, and said radiator consisting of a coiled pipe extending around the chamber in proximity to its Wall, and a second chamber located within the first chamber having a fluid inlet at its top and a fluid discharge opening at its bottom into said first chamber, and discharge means at the top of the first chamber, said chamber having a cross-sectional area greatly exceeding its inlet area.

6. In a heat transfer device, an oil receptacle, an electric heating element in the receptacle, a heat radiator, means for circulating heated oil from the receptacle through the radiator and back to the receptacle, said element being positioned to be submerged in and along the path of oil travelling through the receptacle during said circulation, a chamber, and said radiator consisting of a coiled pipe extending around the chamber in proximity to its wall, and a second chamber located within the chamber having a fluid inlet at its top and a fluid discharge opening at its bottom into said first chamber, and

discharge means at the top of the first chamber, 75

said coiled pipe being between said first and second chambers to receive discharge from the second chamber thereacross.

7. In a furnace, a major chamber, an oil receptacle in the bottom of the chamber, a heat radiating coil interconnecting by inlet and discharge ends to the receptacle and mounted to extend around the wall of the chamber between the top and bottom thereof, said receptacle and coil being filled with a light oil, a pump between the receptacle and the coil inlet end, an electrical heating unit in the receptacle for heating the oil, said coil inlet end being at the lower part of the coil and the discharge end at the upper part thereof, a second chamber carried within said coil and opening over said receptacle, the second chamber having its wall in close proximity to said coil and having an upper inlet of less cross-sectional area than that of the chamber, said first chamber having a discharge opening at its upper end.

ELWELL J. PECK.

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