US3108174A

US3108174A - Heavy duty heaters for gases

Info

Publication number: US3108174A
Application number: US205647A
Authority: US
Inventors: Lee P Hynes
Original assignee: HYNES ELECTRIC HEATING Co
Current assignee: HYNES ELECTRIC HEATING Co
Priority date: 1962-06-27
Filing date: 1962-06-27
Publication date: 1963-10-22
Anticipated expiration: 1980-10-22

Description

Oct. 22, 1963 L. P. HYNES HEAVY DUTY HEATERS FOR GASES Filed June 27, 1962 4 Sheets-Sheet 1 llll INVENTOR Lee flywai ATTORNEYS Oct. 22, 1963 L. P. HYNES HEAVY DUTY HEATERS FOR GASES 4 Sheets-Sheet 2 Filed June 27, 1962 llllllllllll l.

INVENTOR Lee K @1280 Oct. 22, 1963 Filed June 27, 1962 L. P. HYN ES HEAVY 'DUTY HEATERS FOR GASES 4 Sheets-Sheet 3 I VENTOR Lee @056 e g... 1.. Q5,

ATTQRNEYS Oct. 22, 1963 1.. P. HYNES 3,103,174

HEAVY DUTY HEATERS FOR GASES Filed June 2'7, 1962 4 Sheets-Sheet 4 INVENTOR Lee E #yner are likely to be gases.

United States Patent 3,108,174 HEAVY DUTY HEATERS FOR GASES Lee I. Hynes, Haddoniield, Ni, assignor to Hynes Electric Heating (10., Kenilworth, N..l., a corporation of New Jersey Filed June 27, 1962, Ser. No. 205,647 Claims. (Cl. 219--38) The present invention relates to electric heaters for fluids, especially gases, including air.

A purpose of the invention is to provide a more flexible arrangement in fluid heaters.

A further purpose is to utilize a casing to continuously support a heater.

A further purpose is to provide a heater frame formed of metal segments.

A further purpose is to eliminate supporting bearings for the heater element.

A further purpose is to provide a more simple arrangement wherein the entire heater assembly is prefabricated outside the heater pipe or casing and then inserted into a pipe or casing.

A further purpose is to eliminate supports for the heater structure in the form of cross pieces welded in the casing.

A further purpose is to eliminate the necessity for access to both ends of a casing to insert the heater in the casing, since the heater is self-supporting without,

end bearings.

A further purpose is to provide a prefabricated selfsupporting heater assembly rigid enough to be safely shipped to a point of installation and which can be readily inserted into a casing which has already been installed.

A further purpose is to utilize the frame to protect the ceramic insulators from damage during shipment, installation and use.

A further purpose is to protect the resistor ribbons from mechanical and electrical damage by supporting them freely between insulators.

A further purpose is to enable a heater to be inserted into a casing from one end only of the casing.

Further purposes appear in the specification and in the claims.

In the drawin s 1 have chosen to illustrate a few only of the numerous embodiments in which my invention may appear, selecting the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a fragmentary perspective view of the heater of the invention with the casing broken away.

FIGURE 2 is a fragmentary axial section of an electric heater in accordance with the invention, omitting the extended portions of the casing at the ends, taken on the line 2-2 of FIGURE 3.

FIGURE 3 is an end view partly in section, showing the heater of the invention.

FIGURE 4 is a fragmentary section taken on the line 4-4 of FIGURE 3.

FIGURE 5 is an end view of a variation of the heater of the invention.

FIGURE 6 is an enlarged fragmentary exploded view of the heater of the invention without the resistor ribbons.

Describing in illustration but not in limitation and referring to the drawings:

The present invention is applicable to the heating of fluids, which may permissibly be liquids, but in most cases When reference is made herein to gas or gases, it is intended to include air and one of the advantageous uses of the present invention is to heat air for testing guided missiles, jet engines and for use in Wind tunnels and the like.

The invention is particularly applicable for heating gases under high pressure and high temperatures. For example, the invention could be used to heat gas under a pressure of 5,000 p.s.i. to a temperature of 1800 F.

The invention is also applicable for heating gases utilized for example in the chemical industry. One example is heating of hydrogen and nitrogen which are being passed over a catalyst suitably at several thousand p.s.i. and at elevated temperatures. which may be as high as 1700 F. or more in order to make ammonia. Many of the installations in which the equipment of the invention will be applied are characterized by high temperature alone or by high pressure alone or both high temperature and high pressure.

The invention is applicable also to installations embodying intermediate and low pressure and also to those in which moderate pressure or temperature is employed.

The invention is concerned with a heater which extends parallel to a fluid flow in a pressure vessel or casing of generally cylindrical shape.

My patent for Fluid Electric Heater, 2,790,889, granted April 30, 1957, provides a very satisfactory heater of the above type. It is necessary, however, to suspend the heater elements and insulators from a central longitudinal rod-like element supported by bearings at both ends from abutments welded or otherwise joined to the casing. The present invention eliminates the need for central bearing by utilizing a longitudinally extending segmented frame which rests against the casing walls, thereby utilizing the casing itself to support the heater. Furthermore, the present invention utilizes a radial arrangement of the segmented frame to provide strength and protection for the electrical elements.

In accordance with the invention, a frame is assembled from sheet metal welded or otherwise connected together. The frame acts to support radially spaced insulators which receives radially directed, longitudinally extending resistor ribbons. The insulators and resistor ribbons are held in place between the frame members by retaining elements. The frame rests on and is supported within a pressure casing.

The fiuid to be heated passes through casing 20, such as a pipe or cylinder, of sufficient structural strength to withstand the fluid pressure. A heater 2i. rests within the casing. The heater 21 comprises a frame 22 which extends longitudinally for the length of the heater. The frame 22 is composed of frame segments 23 which may be of any desirable metal, for instance, stainless steel, Inconel, high chrome steel or of a nickel alloy of any type material capable of withstanding the high fluid temperatures.

The frame segments 23 have radial flanges 24 which extend from a base 25'. The base 2:"? extends in a plane normal to a plane bisecting the angle included by the radial flanges 24. The base 25 can be of any width but desirably the width of the base will be such as to give adequate support to the electrical elements as will be explained. The base 25 has a plurality of spaced holes 26 spaced longitudinally of the segment 23.

The segments 23 extend longitudinally in circumferential relationship with the radial flanges 24 abutting. The number of segments used will be determined by the angle at which the radial flanges 24 are disposed to one another in an individual segment. For instance, in the form of FIGURE 3 the segments have radial flanges which form an included angle of substantially so that three segments circumferentially disposed to one another would be necessary to form a complete frame 22. ()n the other hand, in the embodiment of FIGURE 5, the radial flanges in an individual segment form an included angle of substantially 60 so that six segments would be ararcane ranged circumferentially to form the frame 22 for the heater.

The angle at which the radial flanges are disposed to one another in an individual segment is determined primarily by the heater diameter wherein generally speaking, the larger the diameter the smaller the included angle formed by the flanges and the greater the number of segments necessary. For instance, in FIGURE 3 the diameter is conceivably six inches while in FIGURE the diameter could conceivably be twelve inches.

The frame segments 23 are joined as by welding along their abutting radial flanges 24 as, for instance, at 27.

The bases 25 of the frame segments will form in cross section a regular straight sided figure which will vary depending on the number of segments used. These will include the triangle shown in FIGURE 3 and the hexagon shown in FIGURE 5.

At the base of the segments and guided by the radial flanges, I place at spaced longitudinal positions an inner insulator of suitable ceramic material which conforms at its radial inward side to the contour of the frame segment 23.

The insulator 30 has a base 31 and radial faces 32 and 33. The radial outward surface 34 of the insulator 39 is circumferential. The circumference 34 has a plurality of circumferentially spaced grooves 35 which extend in a direction longitudinal of the heater. The ceramic insulators 30 have a length 36 which may vary in order to give adequate support in the heater but which, for instance, can be of the order of two inches. On the base 31 there extends a boss 37 which conforms in cross section to the opening 26 in the segment base 25. The insulator 3i) rests against the base 25 with the boss 37 extending through the openings 26. The purpose of this is to position the insulators 30 longitudinally in the frame segment 23. It should be understood that any suitable means may be used in place of the boss and holes to position the insulators. For instance, ears could be lanced from the frame segments 23 to engage the insulators.

Resistor ribbons 40 extend longitudinally along the heater and lie in radial planes. The radially inward edge of the ribbon 4t) rests and is supported by the grooves 35 in the insulator 39. The radially outer edge of the ribbon rests at 42 in grooves 43 of outer insulator 44. The outer insulator has an inner circumferential face 45, an outer circumferential face 46, transverse faces 47 and 48, and radial faces 50 and 51.

The inner circumference face 45 with longitudinally extending circumferentially spaced grooves 43 suitably positions and secures the resistor ribbons 40.

The outer circumferential face 46 has a circumferentially extending groove 52 which receives a clamp 53 of desirably arcuate shape having offset portions 54. The radial flanges 24 of the frame are of suflicient length in a radial direction to receive the offset 54 when the clamp 53 is exerting a retaining force on the insulator 44 and the offset 54 is joined to the flange 24 at 55 as by welding or the like. The purpose of clamp 53 is to retain the insulator 44 longitudinally and radially. It should be understood that although the clamp 53 is shown as a continuous are, any suitable form which accomplishes the purpose of locating the insulator 44 may be used. However, by using a continuous arc clamp, we have the added advantage of a structural tie which bridges the radially extending flanges 24.

As best seen in FIGURE 1, the

insulators

30 and 44 and the clamp 53 are spaced longitudinally along the heater frame 22 to yield adequate support of the resistor strips 40. This longitudinal spacing is a matter of choice and may vary to achieve any desired stiffness.

Current is arranged to pass in series through selected groups of resistor ribbons 4i) and for this purpose electrical jumpers 56 are welded to adjoining arms of every alternate pair of resistor ribbons at one end of the heater and jumpers are welded to the adjoining arms of every intervening pair of resistor ribbons at the opposite end of the heater, thus providing for current flow in zig-Zag relationship (series). The groups are selected on the basis of the electrical phase arrangement desired. For instance, in the case of a single phase for the entire heater, the current would pass through all ribbons in series. This would also be true in the case of a heater utilizing direct current. For a three phase heater, the heater of FIGURE 3 for instance would be arranged so that the six ribbons in each of the three frame segments would be connected in series for each phase. In FIGURE 5, for instance, the ribbons in any two adjacent segments could be connected in series to form one phase. The jumper 56 may be, for instance, heliarc welded to the ribbons 49. The jumper is welded to the ribbons so that the metal of the jumper is edgewise to the flow of the fluid.

The electrical connections are conveniently made through leads 60 which may extend longitudinally of the heater and connect through terminal strip 61 of the heater. The leads 60 are brought through the casing wall by suitable insulated pressure type seals.

. It should be understood that the basic structural support of the heater comes from the casing itself, since the frame 22 of the heater rests against the casing.

However, the frame also has inherent strength by virtue of the ararngement wherein the flanges of the frame extend radially.

In assembling the heater of the invention, the frame segments 23 are placed in a longitudinally extending, circumferentially displaced relationship so that the flanges 24 are spaced symmetrically within a circle and are welded or otherwise joined at 27. Inner insulators 30 are placed on the base 25 of each of the frame segments 23 with the boss 37 extending through a hole 26. Resistor ribbons are placed longitudinally in the slots 35 of resistor 36 so that they extend radially in the circle formed by the segments. Outer insulators 44 are then placed on the resistor ribbons 40 so that the grooves 43 receive the resistor ribbons.

Clamps 53 are then placed in the grooves 52 of the insulators 44 and the offsets 54 are then joined as by welding to the flanges 24 at 55. The electrical jumpers 56 and tenminal strips 61 are then welded in place, and the terminals 60 installed.

In inserting the heater 21 in the casing 20, access is only necessary to one end of the casing. The heater is merely inserted in the end and pushed into the casing.

Suitable provision is made for anchoring the heater frame 22 at the terminal end, so that heat expansion and contraction can take place without creating stress on the electrical terminals. This would also permit mounting the heater casing vertically with terminals at the bottom end.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

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

l. A fluid heater including a generally cylindrical casing, a self contained resistor unit within said casing comprising a longitudinally extending frame in abutting relation with the inner surface of the casing and having at least three spaced radially outwardly extending frame elements forming with the inner surface of the casing at least three longitudinally extending resistor receiving passageways, a plurality of longitudinally spaced and positioned inner insulators supported on the frame adjacent the radial inward portion of each of the passageways and each having a plurality of longitudinally extending outwardly directed slots spaced apart along the outer periphery thereof, resistor ribbons extending longitudinally through the passageways in radial planes, the radial inner edges of said ribbon being positioned in said slots in said inner insulators, a plurality of longitudinally spaced and positioned outer insulators each supported between an adjacent spaced pair of said radially directed elements of said frame and occupying the radially outward portion of said passageways and each having a plurality of longitudinally extending inwardly directed slots spaced apart along the inner periphery thereof, said slots receiving and supporting the radial outer edges of said resistor ribbons, and clamps extending from each radially directed frame element to the next and secured at opposite ends to the outer portions of said radially directed elements, said clamps retaining said outer insulators, ribbons, and inner insulators in assembled relation.

2. A fluid heater of the character indicated in claim 1, wherein interlock means are provided between the inner insulators and the frame to limit relative movement thenebetween. 1

3. A fluid heater of the character indicated in claim 2, wherein said interlock comprises at least one projection on each of said inner insulators and corresponding projection receiving openings in said frame.

4. A fluid heater of the character indicated in claim 1, wherein the outer periphery of each of said outer insulators is provided with a groove and said clamps are seated in said grooves and restrain said outer insulators against longitudinal movement.

5. A fluid heater of the character indicated in claim 3, wherein the outer periphery of each of said outer insulators is provided with a groove and said clamps are seated in said grooves and restrain said outer insulators against longitudinal movement.

References Cited in the file of this patent UNITED STATES PATENTS 2,058,769 Brown Oct. 27, 1936 2,536,747 Hynes Jan. 2, 1951 2,790,889 Hynes Apr. 30, 1957

Claims

1. A FLUID HEATER INCLUDING A GENERALLY CYLINDRICAL CASING, A SELF CONTAINED RESISTOR UNIT WITHIN SAID CASING COMPRISING A LONGITUDINALLY EXTENDING FRAME IN ABUTTING RELATION WITH THE INNER SURFACE OF THE CASING AND HAVING AT LEAST THREE SPACED RADIALLY OUTWARDLY EXTENDING FRAME ELEMENTS FORMING WITH THE INNER SURFACE OF THE CASING AT LEAST THREE LONGITUDINALLY RESISTOR RECEIVING PASSAGEWAYS, A PLURALITY OF LONGITUDINALLY SPACED AND POSITIONED INNER INSULATORS SUPPORTED ON THE FRAME ADJACENT THE RADIAL INWARD PORTION OF EACH OF THE PASSAGEWAYS AND EACH HAVING A PLURALITY OF LONGITUDINALLY EXTENDING OUTWARDLY DIRECTED SLOTS SPACED APART ALONG THE OUTER PERIPHERY THEREOF, RESISTOR EXTENDING LONGITUDINALLY THROUGH THE PASSAGEWAYS IN RADIAL PLANES, THE RADIAL INNER EDGES OF SAID RIBBON BEING POSITIONED IN SAID SLOTS IN SAID INNER INSULATORS, A PLURALITY OF LONGITUDINALLY SPACED AND POSITIONED OUTER INSULATORS EACH SUPPORTED BETWEEN AN ADJACENT SPACED PAIR OF SAID RADIALLY DIRECTED ELEMENTS OF SAID FRAME AND OCCUPYING THE RADIALLY OUTWARD PORTION OF SAID PASSAGEWAYS AND EACH HAVING A PLURALITY OF LONGITUDINALLY EXTENDING INWARDLY DIRECTED SLOTS SPACED APART ALONG THE INNER PERIPHERY THEREOF, SAID SLOTS RECEIVING AND SUPPORTING THE RADIAL OUTER EDGES OF SAID RESISTOR RIBBONS, AND CLAMPING EXTENDING FROM EACH RADIALLY DIRECTED FRAME ELEMENT TO THE NEXT AND SECURED AT OPPOSITE ENDS TO THE OUTER PORTIONS OF SAID RADIALLY DIRECTED ELEMENTS, SAID CLAMPS RETAINING SAID OUTER INSULATORS, RIBBONS AND INNER INSULATORS IN ASSEMBLED RELATION.