US1999446A

US1999446A - Transformer coupled induction heater

Info

Publication number: US1999446A
Application number: US692380A
Authority: US
Inventors: James K Delano
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-10-06
Filing date: 1933-10-06
Publication date: 1935-04-30
Anticipated expiration: 1952-04-30

Description

April 30, 1935.

J. K. DELANO TRANSFORMER COUPLED INDUCTION HEATER Filed Oct. 6, 1935 2 Sheets-Sheav 1 3nventor dam es K. .Delavm.

I Gttomeg April 30, 1935. J. K. DELANO TRANSFORMER COUPLED INDUCTION HEATER- Filed Oct. 6, 1953 2 Sheets-Sheet 2 Enventor (James hi. Delano.

Patented Apr. 30, 1935 PATENT OFFICE TRANSFORMER COUPLED INDUCTION HEATER James K. Delano, New York, N. Y.

Application October 6, 1933, Serial No. 692,380

8Claims.

This invention relates to an electrically operated heating device or unit for the heating of water and the generation of steam, or the heating of any other fluid, such as oil, etc., and in its broad application may be made to heat metals for use in various apparatus where a highly efficient heating effect is required.

The invention employs novel methods for carrying out the idea of direct heating of the liquid, eliminating the use of insulation between the electrical conductor and the liquid, thus greatly increasing the transfer of heat and saving the losses which occur when packing and insulation are present as used in the usual resistance types of heaters.

The method that I employ makes use of the heat generated in an electrical winding which is shortcircuited within itself and subjected to an alternating magnetic field.

For the purpose of description, I show in the drawings, a transformer which has the usual closed magnetic circuit, a primary winding'and a secondary winding composed of a copper pipe coil wound over the primary and insulated there-' from and having the coils of the pipe connected together so as to be entirely shortcircuited within the magnetic field.

As the pipe secondary is shortcircuited there will be no voltage generated which would be harmful in handling.

With the proper amount of cross section of copper in the secondary coil the amperage will be high enough to cause the coils to heat, and by designing the primary winding, turns. ratio, etc., the proper magnetic circuit, the heater can be held to close limits of temperature.

By pumping or circulating liquid through the secondary copper pipe coil the fluid will be heated very efficiently as-it is held during its circulation directly in contact with the heated surface of the pipe coil. In the case of steam, the water is pumped into the pipe coil, and the design of the coil is such as to permit a heating effect of over 212 degrees, steam being generated. If a flash boiler effect is wanted to raise steam instantly, the secondary current can be increased until the turns or pipe coils are well above the boiling point of water, and by limiting the amount of water entering the coils the steam can be raised quickly toa superheated degree.

Thermostatic controls can readily be applied to the unit for controlling its operation.

Water can be heated very efiiciently for various purposes and the secondary may consist of a single large capacity pipecoil, or it may conion.

sist of numerous small turns or pipe coils for other applications and uses.

The primary is so designed that it will deliver to the secondary only a magnetic flux of limited capacity, else the current in the secondary might 5 be high enough to cause the primary current to go too high, causing insulation difliculties.

This is accomplished by making the core of the transformer of such shape and proportions that magnetic leakage tends to limit the current, 10 and it is also important to limit the cross section of the secondary pipe coil.

Other metals than copper, such as iron may be used for'the secondary pipe coil, which will, due to its resistance temperature coeflicient, be practically self-regulating as to its heat and current, this being useful in a water heating storage system to cut the current down when a certain capacity of water has reached a given degree of temperature.

For high steam generation, a preheater pipe coil can be wound inside of the steam generating pipe coil, this preheater pipe coil can .be of the same material or of a different resistance material than the main pipe coils, as it is in the magnetic field it receives current whichheats it independent of the main pipe coil, the cold water being pumped into this first pipe coil where it is heated and delivered to the. main pipe coil, where it is converted into steam, the inner or preheater pipe coil is shortcircuited where it enters and leaves the main pipe coil, and this method of preheating the cold water is very efiicient and steam can be raised from cold water in a boiler of this type in a few seconds, and I have shown this arrangement in one of the drawings.

In the drawings, I have shown a simple application of the principle as applied to a water heating system and it is understood that various heating arrangements could be arranged to take advantage of this principle of heating as described, and that various regulators could be ar anged to control the operations of the device.

With these and other objects in view my invention consists in certain construction and combination of parts as will hereafter be fully described and claimed, and illustrated in the accompanying drawings which form a part hereof and in which like figures of reference refer to corresponding parts in all of the views, and it is understood that slight changes may be made without departing from the spirit of the inven- In the drawings: Figure 1 shows a front elevation of the device without any outer casing or mounting means,

as these will vary with the use to which the device is applied and are not important as regards its operation, and have therefore been omitted from the drawings.

Figure 2 shows a side elevation of the same.

Figure 3 shows a top plan view of the same.

Figure 4 is a diagrammatic view, showing the application of the device to a water heating system.

Figure 5 shows a front elevation of another form of the device illustrating the method employed for preheating the liquid.

Figure 6 is a top plan view of the same, both of these Figures 5 and 6, being shown partly in section.

Referring to the drawings:

The heater comprises as here shown, an electrical transformer composed of the core or laminations l0, upon which is mounted and insulated therefrom by the insulation strips Ii, the primary winding l2, which is connected into the current supply by the wires l5, which supply electrical current of the propertype and voltage to said coil i2. 7

As shown in Figures 1, 2 and 3, the secondary comprises a coil formed by a pipe l3 which is coiled and mounted upon the primary winding I2 and insulated therefrom by the packing I6, which is also employed to cover the coils l3 and retain the heat therein.

This secondary coil I3 is employed to heat the liquid which is caused to flow therethrough, and the heating is effected by shortcircuiting these coils l3 by the strips ll which are attached thereto by brazing as at [1, or some other suitable means, and these strips I may also be used for the mounting of thermostatic controls.

The secondary pipe coil I3 being thus shortcircuited within the magnetic field will become very hot, and will cause the liquid passing there through to become heated to and above the boiling point if desired, depending upon the speed with which the liquid is forced through the coil I3 and the design of the heater.

In Figure 4, the heater is shown as mounted in a hot water system, and attached by the flow pipe and return pipe to a water supply l8 having a flow pipe is and a return pipe 20, to the heating radiators, etc.

For the purpose of preheating the cold water or other liquid before it is brought into direct contact with the heated secondary pipe coil 13, I have shown in Figures 5 and 6, a transformer comprising the core l0, having a primary winding [2 mounted upon one leg thereof, and a main secondary hollow pipe coil l3 mounted upon the other leg of the transformer [0, while mounted upon the same leg or some other part. of the transformer is a preheater coil 24 of a smaller diameter pipe 2|, through which the liquid is passed by the pump 22 or other means from a feed Pipe 23.

This preheater coil 24 is given a few turns about the transformer and is then inserted into the upper coil of the main pipe coil I 3, and is mounted within said coils I3 for their entire length, its lower end being mounted in the plugged or closed end 21 of the coil I3, the end of said pipe 2| being also closed upon the end, but provided with an opening 25 in its side adjacent the end, through which the preheated liquid is admitted to the pipe coils I3, the direction of travel of opposite to that of the steam within the pipe l3, so that in this manner the pipe 2| enters the hottest part of the coil l3 and the liquid is carried through the steam heated coil l3 and by the time it is released therein it has been converted into steam, thus producing a flash type of electrically heated boiler.

Various thermostatic controls can be employed in connection with the primary circuit to turn on and oil, or regulate the current to produce a given temperature in the secondary or heating element. Such thermostatic devices may be of any of the well known types now in use and need not be described in detail, as any one skilled in the art can readily apply such controls to accomplish a desired result.

It is understood that this heater generates heat by the high amperage developed in the low resistance secondary coils and it has been found that the efficiency is higher than in the resistance type of heater, when applied in its various forms for a specific purpose.

I have not attempted to give data as to the winding turns, iron, etc, as these will vary with the uses to which the invention is to be put.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an electrically operated steam boiler, comprising an electrical transformer having a laminated iron core designed to produce a closed magnetic field, a primary winding thereon and insulated therefrom, a hollow secondary coil winding within said magnetic field and insulated therefrom and having a closed end, a shortcircuitin member connected to the convolutions of said secondary coil to form a closed circuit within itself, a second tubular coil mounted within said magnetic field and having a portion of its convolutions shortcircuited to form a local circuit and having one of its ends wound spirally within the convolutions of the secondary coil and formed with an opening near its closed end adjacent to the closed end of the secondary, and means for admitting water through said second inner coil to the closed end of the secondary coil.

2. In an electrically operated steam boiler, the combination with an electrical transformer having a laminated iron core designed to produce a closed magnetic field and a primary winding thereon and insulated therefrom, of a hollow secondary coil winding formed with one of its ends closed and mounted on said transformer and insulated therefrom, the convolutions of which are shortcircuited to form local circuits, a second tubular coil of smaller diameter mounted within the same magnetic field and having a portion of its convolutions shortcircuited to form local circuits, and a portion of its convolutions contained within the convolutions of the secondary coll, said second coil having a closed end formed with an opening adjacent thereto and to the closed end of the secondary coil.

the liquid being Cl 3. In an electrically operated steam boiler, the

combination with a transformer having a laminated iron core designed to produce a magnetic field and a primary winding mounted in the magnetic field and having a portion of its convolutions shortcircuited and some mounted within the convolutions of the secondary coil, the

- inner end of said preheater coil closed and formed with an opening adjacent to and within the closed end of the secondary coil, means for passing water through said preheater coil to preheat the same and to deliver the water in the form of steam to the closed end of the secondary coil and means for preheating the steam thus generated within the secondary coil.

4. In a liquid heater, an electrical transformer having a laminated core and a closed magnetic circuit and a primary winding connected directly across the current supply mains, a secondary tubular coil winding mounted on said transformer within the magnetic field, a shortcircuiting means connected to each of the convolutions of said secondary coil forming local circuits therein.

5. In a heater for liquids, an electrical transformer designed to producea closedmagneticfield, a single primary winding thereon and connected directly across the current supply mains, a hollow secondary coil winding mounted on said transformer within the magnetic field and having each of its convolutions shortcircuited, and a hollow preheater coil having a portion thereof mounted within saidhollow secondary coil for the purpose of discharging the liquid therein at the closed end of said secondary coil.

6. In a liquidheater, an electrical transiormer having a laminated iron core designed to produce a closed magnetic field, a single primary winding mounted on said core and-connected directly across the current supply mainaasecondarytubular coil winding mounted over said primary windcoil winding mounted on said transiormerwithin the magnetic field and insulated both from the primary coil and the transformer core, shortcircuiting bars connecting each of the convolutions 01 said secondary coil to form local circuits within the magnetic field, and means for passing the liquid to be'he'ated through said secondary coil.

8. In a heater for liquids, an electrical transformer designed to produce a closed magnetic field, a single primary winding thereon'and connected directly across the current supply mains, a hollow secondary coil mounted on said transiormer within the magnetic field and having each oi its convolutions shortcircuited to form local circuits, a closed end formed on said secondary coil, a hollow preheater coil having a portion thereof contained within the secondary coil with its discharge end adjacent to the closed end of the secondary coil, said preheater coil adapted to'be heated and the liquid passing therethrough by the steam generated within the secondary coil and by the induced current due to the shortcircuiting oi the preheater coils.

JAMES K. DELANO.