Title:
Induction heated pipe
United States Patent 2178720
Abstract:
This invention relates to electrically heated pipes, conduits and process lines. More particularly it relates to an induction heated non-magnetic pipe or conduit construction. Still more particularly it relates to an insulated non-magnetic pipe or conduit construction which is provided with...


Inventors:
Daniels, Charles E.
Application Number:
US19214238A
Publication Date:
11/07/1939
Filing Date:
02/23/1938
Assignee:
Pont DU.
Primary Class:
Other Classes:
219/643
International Classes:
H05B6/02
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Description:

This invention relates to electrically heated pipes, conduits and process lines. More particularly it relates to an induction heated non-magnetic pipe or conduit construction. Still more particularly it relates to an insulated non-magnetic pipe or conduit construction which is provided with means for heating the same by electrical Induction.

It is an object of this invention to provide an efficient means of heating a non-magnetic pipe, conduit or process line. A further object is to provide a pipe line construction capable of being maintained at a uniform elevated temperature.' A still further object is to provide a pipe or conduit construction which is simple in design, electrically heated, and requires no replacement of parts.

The ordinary methods of heating process lines such as those used in the chemical and related industries comprise jacketing them with a high temperature heating medium, electrical heating utilizing container resistance or resistor elements, or by direct fire of combustible materials. Each of these methods has distinct disadvantages which definitely limit its usefulness. 'For instance, electricar resistor heaters localize the application of their heat and require frequent replacement, while direct fire heating is bulky, inefficient due to heat losses from radiation, and convection, and entails a constant fire hazard.

The above objects are accomplished free from the disadvantages mentioned, by the following invention, which comprises a novel pipe conduit or process lUne construction. The novel construction comprises a pipe composed of non-magnetic material such as copper, brass, aluminum, etc. which has a plurality of magnetic elemnents disposed about the periphery or exterior surface of the pipe in thermal transfer relationship therewith. The elements are surrounded by insulating material which in turn is encircled by a wire coil which is supplied with an alternating electrical current. The alternating current sets up lines of flux in the said magnetic elements which raise the temperature of the same and also raise the temperature of the pipe or conduit since the elements are engaged in thermal relationship with the pipe.

The nature of this invention will be more fully understood by the devices described below and illustrated in the accompanying drawing, wherein similar reference numerals refer to similar parts throughout the several views.

Fig. 1 is a side elevation of a pipe section with 65 certain parts shown in section.

Fig. 2 is a cross-section taken along the lines 2-2 of Fig. 1.

Fig. 3 is a cross-section taken through the pipe showing a modified type of magnetic element.

Fig. 4 is a cross-section taken through the pipe showing a modified type of magnetic element.

Fig. 5 is a cross-section taken through the pipe showing a modified type of magnetic element.

SIn the drawing the non-magnetic pipes or conduit I has disposed about its periphery a series of elements 2 which are relatively small in crosssection and of appreciable length and are composed of magnetic material such as iron. The elements may be round, square, flat, polygonal, 16 angular or channel-shaped in cross-section and are maintained in a fixed 'position to the line by a bolted clamp 3. The rods, etc. are preferably uniformly spaced about the exterior surface of the pipe or conduit. Totally surrounding the rods and clamping means is the heat insulating material 4, about which is coiled the electrical wire windings 5 which is connected to any suitable alternating current supply.

The electrical current flowing in the wire coils 5 sets up flux lines in the magnetic rods 2 inducing therein electrical currents which are dissipated as hedt. Due to the actual contact and enclosed association of the rods 2 with the process line or pipe I, the heat generated is rapidly transferred to the process line. Actual tests have shown that the temperature difference between the rods and line may be reduced to a negligible amount.

The total cross-sectional area of the magnetic rods as compared with the cross-sectional area of the pipe may vary widely, depending upon the materials to be conveyed and the temperatures desired to be maintained. The total cross-sectional area of the magnetic rods preferably should at least be equal to the cross-sectional area of the walls of a standard iron pipe having the same internal diameter as the non-magnetic pipe such as a copper pipe. The magnetic rods are preferably straight but may be sinuous or otherwise irregular in shape. The magnetic rods may furthermore be clad with a non-magnetic heat conducting coating.

I have found that a copper pipe assembled as above described with round rods having a total area equal to the wall area of an iron pipe of the same size can be effectively maintained at an elevated temperature of 1500 to 4000 C. for example. Using a wire having 10 turns per foot of pipe when connected to a 110 volt and 85 ampere supply, temperatures in the neighborhood of 2750 to 3250 may be easily maintained.

In general with two inch pipe, 600 to 700 turns are used per 60 feet of pipe length at 110 volts Sand 70 amperes. For 120 feet of pipe two circuits or a higher voltage would be used.

In a compending application, filed upon an even date herewith, entitled "Induction heated fixtures", I have disclosed a removable fixture in an induction-heated magnetic pipe line, the heating coils whereof being arranged so as to maintain the removable fixture at substantially the same temperature as the rest of the line.

The fixtures may be similarly mounted in an non-magnetic pipe line of the type set forth above, by increasing the ampere turns adjacent to opposite sides of the fixtures.

While the forms of invention herein disclosed constitute a preferred form hereof, it is to be understood that other forms might be adopted without departing from the spirit of the invention which is to be limited only by the scope of the appended claims.

I claim: 1. A pipe construction comprising a tubular core of non-magnetic material, a plurality of longitudinally disposed flux carrying elements disposed about the core in thermal relation therewith, insulation disposed about said members and 80 core and an induction heating coil arranged about said insulation.

2. A tubular core for conveying fluids composed of non-magnetic material, a plurality of spaced rods composed of magnetic material longitudinally disposed about and in thermal relationship with the exterior of said core, insulation disposed about said members and core, and an alternating current coil disposed about said insulation. 3. A pipe construction comprising a tubular core of non-magnetic material, a plurality of longitudinally disposed flux carrying elements of relatively small cross-section and appreciable length spaced equally about the core in thermal relation therewith, a layer of insulating material disposed about said members and core, and an induction-heating coil wound about said layer.

4. A pipe construction comprising a tubular core of non-magnetic material, a plurality of rodlike magnetic elements spaced equally about the core in thermal relation therewith, a layer of insulating material disposed about said members and core, and an induction-heating coil wound about said layer. 5. A pipe construction comprising a length of pipe composed of non-magnetic metal, a plurality of rod-like magnetic elements spaced equally around the pipe and extending the length of the same, means for holding the elements in position, a layer of insulating material about said elements and core and an induction heating coil wound about the pipe section throughout its length.

6. The pipe construction according to claim 5 wherein the non-magnetic material is composed of copper and the magnetic elements are iron.

CHARLES E. DANIELS.