US3545532A - Rotary regenerator cleaning arrangement - Google Patents

Description

United States Patent l,558,445 10/ i925 Ljungstrom Inventor Joseph Waltkus Wellsville, New York March 7, 1969 Dec. 8, 1970 The Air Preheater Company, Inc. Wellsville, New York a corporation of Delaware Appl. No. Filed Patented Assignee References Cited UNITED STATES PATENTS 2,8l2,923 11/1957 Schoenherretal 165/5 2,913,228 11/1959 Fibenscher 165/7 3,321,011 5/1967 Kalbfleischetal. l65/7 FOREIGN PATENTS 682,278 11/1952 GreatBritain 165/10 Primary Examiner-Albert W. Davis, Jr. Attorneys-Wayne H. Lang and Eldon H.. Luther ABSTRACT: An arrangement for the rotor of a rotary regenerative heat exchanger whereby a highly effective heat absorbent element thereof is arranged in, axially spaced layers closely adjacent opposite ends of the rotor. By this arrangement a pressurized cleaning fluid such as water, steam or air projected on to the element at the ends of the rotor does not lose any significant portion of its energy while being projected between the nozzle and the element. Foreign deposits on the surface of the element accordingly receive near maximum shock effect from the cleaning fluid and are thus effectively removed from the element so that a clean element may be maintained.

ROTARY R GENER T R c EANINo ARRANGEMENT BACKGROUND or THE INVENTION In rotary regenerative heat exchange apparatus a mass of heat exchange material commonly comprised of packed element plates is positioned'in a hot gas passageway to absorb heat from the hot gases passingtherethrough. As the plates become heated in the hot gas stream they are moved into a spaced gas passageway wherethe heated plates transmit their heat to cooler air or other gases passing therethrough.

As the hot exhaust gases pass through the heat exchanger, soot and fly ash are deposited on the surfaces of the heat transfer plates. Depending upon the temperature and other characteristics of the exhaust gases traversing the heat exchanger, maximum deposits usually accumulate at the hot end or at the cold end of the rotor, that is, at the end of the rotor adjacent the inlet for hot gas or at the opposite end adjacent the inlet for cool air. Should significant deposits accumulate, the operational effectiveness of the heat exchanger may be seriously curtailed.

Various arrangements have been adapted to remove these deposits from the plates by subjecting the deposits thereon to a spray of cleaning fluid such as water, steam or air whereby the energy of thecleaning fluid is effective in dislodging the deposits and leaving a clean mass of element having maximum heat transfer effectiveness and minumum resistance to flow.

The projection of cleaning fluid upon the element in the rotor compartments is usually effected by means of a nozzle carried by the housing adjacent the end of the rotor having maximum deposits thereon. Inasmuch as design requirements of the rotor necessitate placing the cleaning nozzle a significant distance from the end of the rotor, a substantial portion of the energy of the cleaning fluid is usually dissipated after it leaves the cleaning nozzle and before it reaches the element surface to be cleaned. This invention is accordingly directed to an arrangement for a rotary regenerative heat exchanger in which the element of a highly effective form is supported outward from the end of the rotor directly adjacent the outlet of the nozzle for the cleaning fluid and in the space through which the cleaning fluid must usually be projected before it reaches the element on which the deposits are collecting.

SUMMARY OFTHE INVENTION BRIEF DESCRI PTI ON OF THE DRAWING FIG. 1 is a crOssJsectiOn of a rotaryregenerative heat exchanger embodyingthe invention,

FIG. 2 an enlarged -cross sectional view showing the details of the divided rotor comprising the invention, a

FIG. 3 is a cross-sectional view of a circumferential seal on a rotor according to the invention, and

FIG. 4 is across-sectional view of a rotary regenerative heat exchanger constructed in. accordance with conventional design. I I I As illustrated in the drawing the heat exchange apparatus comprises essentially a housing 10 enclosing a rotor 12 containing a mass of heat exchange material 14 that is contacted by'a stream of hot gases entering the housing through an inlet duct 16 and being exhausted through an outlet duct 18 after having traversed the heat exchange material in the compartments therebetween. Cool air or other gas entering the housing through an inlet 22 is exhausted through an outlet duct 24 after having traversed the heat exchange material lying in the compartments therebetween. While the gases are being directed through their respective passageways the rotor 12 is being rotated about its axis by drive means 20in order that each portion of heat exchange element contained thereinmay be alternately subjected to the hot gas and cooler air.

The heat exchange material carried by the rotor usually comprises a mass of heat absorbent plates formed with projections that provide flowpassageways therebetween for the flow of hot and cooler gas. The projections on the plates usually are of such size that they space the plates sufficiently far apart whereby contaminants in the gas stream do not collect upon the surface thereof in such amounts as to interfere with the normal flow of fluid. Occasionally, however, deposits on the plates do interfere with the regular How of fluid, and cleaning means, in the form of a cleaning nozzle 26 on a pivotal cleaning arm direct a pressurized fluid such as air, steam or water on to the heat absorbent plates to remove the deposit collections therefrom and return them to their original clean condition.

Highly effective laminar heat exchange element has been developed wherein an amount of such element has the equivalent heat exchange effectiveness of a much greater amount of conventional element. If the more effective laminar-type element is placed in the rotor of a conventional heat exchanger, only a portion of the space occupied by the original element is required to provide an equivalent heat transfer capacity. Therefore a rotor designed for the use of conventional element therein finds but a fraction of the allotted space required for the utilization of laminar-type ele-.

ment.

Inasmuch as a stated volume of llaminar" element is equal in effectiveness to that of a much larger volume of conventional element, replacement of conventional element with an equivalent amount of that of the laminar-type will result in a rotor having a void space therein. The element is accordingly arranged in spaced layers at the hot and cold ends of the rotor with void therebetween in the manner shown by FIG. 2. This arrangement thus provides for several independent blocks of element, each'of which is relatively small and may be handled with comparative case.

To facilitate mounting each element block 36 within each sector shaped compartment of the rotor, special L-shaped brackets 30 are positioned radially between the central rotor post and the rotor shell 10 and secured by bolts 32 to axially opposite ends of each radial partition 34. The brackets 30 in each compartment face inwardly in order that the horizontal arms thereof may provide supports on which the sides of the element blocks may securely rest during normal operation of the rotor.

The same bolts 32 that secure the brackets 30 to the radial partitions 34 similarly secure the radial sealing members 38 thereto. The radial sealing members being comprised of a thin strip of resilient material flexibly wipe against their respective end plates 40 and 42 to preclude fluid therebetween and thus maintain the flow of fluid in the predetermined channels'of the rotor.

The horizontal arm of each bracket 30 is positioned closely adjacent end plate 40 at the lower end of the rotor and at such a distance from the upper end plate 42 that the upper and lower layers of rotor element 36 are both supported closely adjacent their respective end plates. When constructed according to this arrangement, cleaning fluid being projected outward from the cleaning nozzles 26 to the adjacent blocks of rotor element arrives at the surface thereof with substantially the same energy with which it was exhausted from the nozzle 26.

The radial outer portion of each element block 36 is provided with an arcuate filler plate 46 that is integrally secured thereto and is adapted to slidably abut the annular leaf 48 that is secured to the rotor shell 52 by brackets 54. The same brackets 54 that secure the annular leaf 48 to the rotor shell 52 also hold theflexible leaves which comprise the circumferential sealing means 58. The brackets 54 shown are securely held to the rotor shell by a bolt 56 which may be adjusted to A pqnnit manual ma in j bptinmmsealing fniernbers. n

3 ylntion of nthg ngal ing membgrg and an permi; 1h; supply Qischarge of a heating fluid and a fluid I} :9 hgaled mgans gopatingphgroto: about its axis within the hpusing spacqd layers of laminar heat exchange element at n gxi allyoppqsi tef end s of each compartment adapted to absppb 5 hea t' fl om the h e a ting fluid and impart absorbed heat to-the UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 545, 532 Dated December 8, 1970 Inventor-(a) 1 g h Waitkus It is certified that error appears in the above- -identified pate and that said Letters Patent: are hereby corrected as shown below:

In line 2 of the single allowed claim, delete [therefrom (adapted)] and substitute central therefor.

316MB AND SEALED W8 9 I97! mm E. m.

Attesting Officer nOflllliBBione-r 01' Patbntfl

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