US 1603960 A
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Description (OCR text may contain errors)
Oct. 19 1926. 1,603,960
A. T. LEWIS AIR HEATER Filed April 14, 1923 2 Sheets-Sheet l Oct. 19 1926. 1,603,960
A. T. LEWIS AIRHEATER 7 Filed April 14, 1923 2 Sheets-Sheet 2 %Z 3 Z6 Z4 25 /0 HVVENTOI? 2?; ::2 4Zexazza'er7Zarnfa2z Lewis,
ATTORNEY Patented Qct. 19, 1926.
' UNITED STATES 1,603,960 PATENT OFFICE! ALEXANDER THORNTON LEWIS, OF MERION, PENNSYLVANIA, ASSIGNOR T YORK,
HEATING AND VENTILATING CORPORATION, OF PHILADELPHIA, PENNSYLVANIA,
A CORPORATION OF PENNSYLVANIA.
Application filed April 14, 1923. Serial No. 631,959.
Some of the objects of the present invention are to provide an improvement in unit I heaters; to provide an improved coil construction for heating a circulating medium;
to provide a heating unit in which there are no couplings or other threaded fittings; to provide an air heater of the unit. type wherein provision is made for the free inlet of air from all" sides of the heater and causing the same to circulate in ,anefficient manner through the heater; toprovide an ar-.
rangement of heater coilswherein expansion and contraction can be automatically com- 'pensated and without placing heater connections under strain; to provide a unit heater wherein a natural circulation of the heated medium can take place; and to provide other improvements as will hereinafter appear.
In the accompanying drawings, Fig. 1 represents a front elevatlon in part section of a. unit heater embodying-one form of the present invention; Fig. 2 represents a side elevation, in part section, of the same; Fig. 3 represents a detail in elevation of one form of heater coil; Fig. 4 represents a top plan of the coil shown in Fig. 3 Fig. 5 represents a detail in end elevation of the coil; and Fig. 6 representsa detail section of the pipe jointing.
Referring to the drawings, one form of the present invention comprises a casing 10 of general rectangular form which is open at its lower'end to provide an inlet 11 for air or other medium, and is also open at its upper end to provide an outlet '12 for the medium passing through the casing. Preferably, the casing 10 is mounted on legs 13 so that the inlet 11 .is spaced from the floor line to allow the air to pass freely into the casing 10 from all sides.
In order to increase circulation of air or other medium through the casing 10, a housing 14. is mounted upon the top of the casing lO and serves to support a rotatable fan 15 which is fixed to a shaft 16 journalled in bearings 17 on the exterior of the housing to be out of direct contact with the heat.
The shaft 16 is driven by a pulley 18 from any suitable source of power. The housing 5 ,14 i s of openended construction so that its chamber 20 becomes a' continuation of the chamber 21 formed by the casing 10'. The outletend of the housing 14 is preferably arranged to discharge into a distributing In the form shown the series of pipe coils 26 leads from' one side of the header 24 downwardly in a succession of loops 'to the opposite side of the header 25. The series of pipepoils 27 leads from the side of the header 2 L opposite to the'coils 26, downwardly in a succession of loops to the opposite side of the header 25, but the arrangement of this series 27 is such that it has a staggered relation, as horizontally con sidered, with respect to the series 26. Each of the two series of coils is made up of a plurality of separate pipes which are respectively bent to form parallel lengths connected by end loops and the aforesaid lengths and loopsof each pipe lie in the same vertical plane. Thus, in assembled condition the series of coils 26 is arranged in as many vertically disposed planes as there are pipes in the series, and likewise the series of coils 27 is arranged in as many vertically disposed planes as there are pipes in the series. In assembled condition the coil structure 23 is made up of alternate sections of the two series of coils 26 and 27 arranged in abutting relation so that a tortuous path following a general vertical direction through the coils is provided because of the staggered relation of the pipe lengths which brings the horizontal lengths of pipes of one series opposite the respective spaces between the horizontal lengths of the other series. This construction provides a maximum heat ing surface with whichthe air is brought into intimate contact without placing any abrupt obstruction in the path of flow of the air. Thus, with the heating medium entering byway of the header 24: at the top of the housing and the air entering the inlet 11 at the bottom of the housing, there is provided a highly eilicient counter-current flow whereby the available heat is utilized without waste.
As a means for attaching the ends of each pipe to the respective headers 24 and 25 the latter are suitably drilled in vertically staggered relation at opposite sides thereof for proper spacing of the coils, and after inserting the ends of the pipes in the respective drilled openings they are welded into place as indicated at 28 so that the entire heating coil structure becomes a unitary one without threaded joints, couplings or other fittings ordinarily employed in coil construction. This construction practically eliminates leaking joints and connections, reduces repairs to a minimum, and makes the cost of maintenance so low as to be negligible.
For'connecting the heating coils to a steam line or other source of heat, the headers 24 and 25 project to one side of the casing 10 so that connections can be readily made for causing the heating medium to circulate through the coils. Preferably also the headers 24 and 25 are tied together for strength 'ening purposes by tie bars 30 arranged at opposite sides of the coil structure and having their ends welded to the respective headers toform a rigid construction. Preferably also the headers 24 and 25 are respectively supported and held properly positioned within'the casing 10 by suitable straps 31 and 32, the ends of whieh have Welded connection with angle bar construction of the casing. It will thus be evident that While the headers 24 and 25 are rigidly held by welded strap and tie-bar construction, the coil structure 23 is free to expand or contract throughout its length with a movement somewhat simulating a bellows action though it is held fast at the welded connection with the headers which are not subject to opening up and causing leaks as do the ordinary threaded coupling joints.
From the foregoing it will be apparent that a complete heating unitv has been devised which is simple and operable in construction, economical in operation, and adaptable to a variety of uses. A unit of this character is an ideal heating means for foundries, machine shops and other exposed buildings, and is also effectively employed to supply fresh heated air to rooms in which exhaust systems are used for removing dust fumes or chemical vapor. It has also been found highly eflicient in dispelling fog in .dye houses, paper mills, and packing houses where steam vapor is prevalent.
Attention is further directed to the welded construction of the coil ends with the headers as this results in a thickening of the wall-of the pipe at the joints and gives reinforcement where in prior coil constructions the joints have been weakened owing to the removal of material in cutting the threads for the joints.
While the construction here shown is a vertical type of heater it is to be understood that this is only by way of example and the invention is not'limited to any specific position or arrangement. Also while but a single formis-shown in which the invention may be embodied, it is to be understood that the invention is not limited to any specific construction but might be applied in various forms without departing from the spirit of the invention or the scope of the appended claims.
Having thus described my invention, I claim:
1. In a unit heater, the combination with a casing having an air inlet and an air outlet, of means for causing a circulationof air through said casing, and a coil heating structure supported within said casing comprising two headers, tie bars rigidly holding said headers in spaced relation, Welded means for supporting said headers in said casing, and two series of pipe coils forming a substantially flexible connection between said headers, said series of coils lying respectively in parallel planes and the coils of one series being staggered horizontally with respect tothe coils of the other series.
2. In a unit heater, the combination with a casing having an air inlet and an air outlet, a housing secured to the top of said casing and communicating with said casing, a fan in said housing, means for rotating .said fan to produce a circulation of air through said casing, and a coil heating structure supported in .said casing comprising two headers spaced apart, two series of pipe coils connecting said headers and extending on opposite sides thereof, said series being staggered horizontally with respect to each other with the overlapping portions arranged in substantially abutting relation and the end connections of said series being staggered vertically on opposite sides of the headers.
3. In a unit heater, the combination with a casing having an air inlet and an air outlet, of means for causing a circulation of air through said casing, and a coil heating structure supported within said casing comprising two headers, tie bars rigidly holding said headers in spaced relation, and two Series of flexible connection -between said headers, said series of coils lying respectively in parallel planes and the coils of one series being staggered horizontally with respect to the coils of the other series.
Signed at- Philadelphia, in the county of Philadelphia, State of Pennsylvania, this 11th day of April, 1923.
ALEXANDER THORNTON LEWIS.
pipe coils forming a substantially