US 2303247 A
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J. E. WOQDS HEAT EXCHANGE APPARATUS Nov. 24, 1942.
Filed April 22, 1941 Patented Nov. 24, 1942 HEAT EXCHANGE APPARATUS I John E. Woods, Brookline, Mass., assignor to Clifford Manufacturing 00., Boston, Mass., a
corporation of Delaware Application April 22, 1941, Serial No. 389,770 2 Claims. (Cl. 257-236) The present invention relates to heat exchange apparatus, and is more particularly concerned with heat exchange apparatus such as radiators, intercoolers, etc., involving thin-wall, closely spaced tubes of copper, aluminum or other nonferrous metal.
The principal object of the present invention is to provide a header type construction of thinwall heat exchange apparatus, with simple and inexpensive means for preventing channeling r by-passing of the fluid at the sides of the apparatus. To this, end, the present invention comprises the apparatus hereinafter described and particularly defined in the claims.
In the accompanying drawing, Fig. 1 is a sectional elevation of the preferred form of heat exchange apparatus according to the present invention; Fig. 2 is a view illustrating the method of mounting the tank or shell; and Fig. '3 is a detail view of one of the pads used for preventing channeling.
the tank. One of the main purposes of the turned-over end portions I8 of the plate is to prevent particles of the pad being carried along with the stream of fluid. With tightly compressed metal wool pads, particularly in cases where the fluid velocities are low, the plate [6 may beomitted, the pads l4 being simply laid in place over the tubes.
As clearly indicated in Fig. 1, the pad is'maintained under some compression so that the free wool material between the edges I8 enters somewhat into the inter-tube spaces.
Y. desirable channeling, while still allowing some The illustrated embodiment of the invention comprises a plurality of closely spaced thin-wall tubes 4, of copper or aluminum, to opposite ends of which are connected header plates 6. Each header plate is formed with a peripheral flange 8 for attachment to the tank or shell In. The tubes are bonded to the headers and the headers are bonded to the shell by a brazing compound or alloy, preferably as described in my co-pending application, Serial No. 389,769, filed of even date herewith. The tank is provided with inlet and outlet connections I2.
In order that the headers may have suflicient rigidity, it is not feasible to form them with tube receiving openings extending too close to the edges. Accordingly, channels of low resistance to fluid how are left between the tank and the outside rows of tubes. In order to prevent such channeling, the spaces between the tank and the outside rows of tubes are filled with material which interposes a resistance to the flowof fluid. This material is preferably in the form of pads, illustrated at I4. These pads are of metal wool of the same material as the tubes and headers or i of a metal or alloy compatible therewith: alternatively they may be of fibrous non-metallic structure, for example, of asbestos or glass wool.
To facilitate assembly and to maintain the pads in place, the pads are preferably made as shown- The pads are placed in the apparatus, as
It has been-found that the pads eliminate unfiuid to, flow about the outside tube rows, so that the latter contribute to the heat transfer capacity of the equipment. 5
The preferred method of mounting the tank 0 the header and tube assembly is illustrated in Fig. 2. The Wool pads are first pressed into place along the sides of the tubes, and. these pads are temporarily retained in place by a thi metal guidesheet 20, which is wrapped around the as-.
sembly. The tank I0 is then slid over the guide sheet, and as the tank is advanced, the guide sheet is advanced with it until the tank finally slides over the flange 8 of the header, shown at the left hand side of Fig. 2. The guide sheet 20 is then easily removed. This method prevents the edges of the tank from catching on the perforations of the plate IE, or on the strands of wool when the plate 16 is not used. Although it is possible to slide the tank into place without using the guide sheet 20, if care is taken, the use of the guide sheet is to be preferred in any case.
After this assembly, the bonding of the headers to the tank is accomplished as described in my above-mentioned copending application.
Having thus described my invention, I claim:
1. Heat exchange apparatus comprising headers, a tank, a bundle of thin-wall tubes secured to the headers, and means for preventing channeling at each side comprising a pad of fibrous \material" and a thin retaining plate for the fibrous material having its ends folded over the ends of the pad, the pads being fitted intothe side spaces between the tank and the outer banks of tubes.
2 Heat exchange apparatu comprising headers, a tank, a bundleof thin-Wall tubes secured to the headers, and means for preventing channeling at each side comprising a pad of fibrous material placed in the side spaces between the tank and the outer banks of tubes, th pad being compressible whereby a part of the materialv thereof enters into the inter-tube spaces in contact with the tubes.
I JOHN E. WOODS.