US2983486A - Element arrangement for a regenerative heat exchanger - Google Patents

Description

May 9, 1951 G. E. ROSENBERG 2,983,486

ELEMENT ARRANGEMENT FOR A REGENERATIVE HEAT EXCHANGER Filed Sept. 15, 1958 COL 0 [N0 United States Patent 0 ARRANGEMENT FOR A REGENERA- TIV E HEAT EXCHANGER Filed Sept. 15, 1958, Ser. No. 761,096

2 Claims. (Cl. 257-265) ELEMENT The present invention relates to improvements in heat transfer apparatus of the rotary regenerative type, and particularly it relates to an arrangement of heat transfer elements that promotes continuous trouble free operation thereof. 1 l

A rotary regenerative heat exchange apparatus of the type herein considered has a cylindrical rotor divided into compartments in which are supported spaced metallic heat transfer plates which as the rotor turns are first exposed to a stream of heating gas to absorb heat therefrom and then, upon rotation of the rotor, they are exposed to cooler air or other fluid to be heated whereby the heat absorbed from the heating gas is transferred to the cooler fluid. Most heat exchangers of this type have their heat transfer plates packed so closely that the channels therethrough are very narrow, and when operated under conditions that promote condensation of moisture from the gases, the fly ash and other products of combustion adhere to the plates thereby reducing the free area of the flow channels between plates. This may result in the clogging of channels, particularly at the cold end of the apparatus where condensation may occur due to the proximity of the cool fluid to be heated.

Various attempts have been made to minimize such clogging by increasing the net free area for gas flow between heat transfer plates and by providing cleaning ap paratus that delivers fluid under pressure to the tightly packed plates to dislodge the deposits and carry them away. Such attempts have been partially successful, however, certain deposits have proven so extremely tenacious that they defy removal by known means. Accordingly, the chief object of this invention is to provide an arrangement of heat absorbent platesfor a regenerative heat exchange apparatus that precludes the accumulation of deposits thereon. This and other objectsof my invention will become more apparent when read in conjunction with the drawing in which:

Figure 1 is a perspective view of a rotary regenerative heat exchanger; and

Figure 2 is an enlarged perspective view of an element arrangement involving this invention.

As illustrated in the drawing, the regenerative heat exchanger which carries the heat transfer plates of this invention comprises a housing enclosing a rotor 12 including a rotor shell carrying heat transfer plates 14 and 16 which are moved first into contact with a heating fluid entering the housing through duct 18 to absorb heat therefrom, and then into contact with a fluid to be heated entering the opposite end of the housing through duct 22. The rotor is turned about its axis by a motor or'the like connected to the rotor post 24 through suitable reduction gearing not here illustrated. The rotor 12 comprises a cylindrical shell 26 connected by radially extending partitions or diaphragms 28 to the rotor post 24 which serve to divide the rotor into a plurality of sector shaped compartments. Sector plates 32 at ends of the housing 10 adjacent ends of the rotor 12 are formed with axially aligned openings for directing the fluids through the rotor. The flow of'the heating fluid and the, fluid to be heated between" the rotor shell 12 and its surrounding housing 10 is prevented by circumferential sealing members carried on the end edges of the rotor shell.

The heat transfer plates 14 comprise a series of undulated, corrugated or otherwise formed sheets that are spaced apart by flat sheets 16 to maintain them in a positively spaced arrangement with suitable flow passageways therebetween. The formed plates 14 are arranged with their flow passageways extending axially between inlet and outlet ends of the rotor in a line generally parallel to normal flow of fluid between inlet and outlet ducts.

The flat sheets 16 are adapted to lie intermediate all portions of the formed plates 14 except that portion lying adjacent the cold end of the rotor in the manner shown in Figure 2. This arrangement provides a double spacing 2d" between plates at the cold end of the rotor while the hot end and intermediate portions of the rotor are conventionally spaced. The proportion of the rotor element provided with a double plate spacing is not critical but is dependent upon fouling conditions that prevail. The plates are preferably packed tightly to prevent their shifting during rotation of the rotor so that it is possible to utilize the specified plate arrangement without regard to rotor disposition.

The cleaning means for this apparatus comprises a conventional cleaning nozzle 46 disposed in the passage for the fluid to be heated adjacent the cold end of the rotor and opposite the heat transfer plates. Here the cleaning nozzle 46 can direct cleaning fluid upon the plates as they rotate slowly while the nozzle itself is pivoted from the rim of the rotor towards its center and then returned to its rim. Steam, air, water or other cleaning fluid is supplied to the cleaning nozzle from 'any suitable pressure source not here shown. As the cleaning fluid strikes the double spaced element portions turbulence in the fluid stream is at once set up causing the unsupported ends of plates 14 to vibrate in the turbulent fluid so as to jar loose fly ash and other deposits clinging thereto thus giving assistance to the erosion effect of the direct fluid blast emanating from the cleaning fluid nozzle 46.

What I claim is:

1. Rotary regenerative heat exchange apparatus or the like having a cylindrical housing including spaced inlet and outlet ducts at opposite ends arranged to permit the counterflow therethrough of a heating fluid and a fluid to be heated, a rotor mounted in said housing adapted to carry a plurality of regenerative heat exchange elements alternately between the heating fluid and the fluid to be heated, said heat exchange elements comprising a series of heat absorbent plates corrugated to provide parallel flow passageways therebetween extending between ends of the rotor, and spacing means intermediate the heat absorbent plates formed as plane metallic sheets extending axially from the end of the heat exchange element lying adjacent the inlet for the heating fluid to a point axially spaced from the outlet therefor whereby the ends of the heat absorbent plates lying adjacent the inlet for the heating fluid are laterally supported by said sheets while the ends of said plates lying adjacent the outlet for the heating fluid are free to vibrate laterally when subjected to the effect of a turbulent fluid.

2. Rotary regenerative heat exchange apparatus or the like having a cylindrical housing including spaced inlet and outlet ducts at opposite ends for the counterflow therethrough of a heating fluid and a fluid to be heated, a rotor in said housing adapted to carry a mass of regenerative heat exchange material alternately between the heating fluid and the fluid to be heated, the regenerative heat exchange material carried by said rotor comprising a plurality of heat absorbent elements having intermediate passageways extending between ends of the rotor; and spacing means intermediate the heat absorbent elements adapted to abut said elements at the end of the rotor adjacent the heating fluid inlet while lying spaced from said elements in the area adjacent the heating fluid outlet thereby promoting lateral vibration of the ends of said elements lying adjacent the heating fluid outlet when subjected to the elfect of a turbulent fluid.

. his I UNITED STATES PATENTS Rydrnark NOV. 11, 1930 Cook June 23, 1931 Gates Mar. 30, 1948 Stark June 11, 1957

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