US2851825A - Apparatus for distributing material equally between a plurality of zones - Google Patents

Description

Sept. 16, 1958 J.PUHR- ESTERHEIDE 2, 5

APPARATUS FOR nrs'rax 'rmc MATERIAL mum? BETWEEN A PLURALITY 0F zouss Filed May 17, 1954 K 30 35 v36 317 37 3a 38 W INVENTOR L/uzyerz u%fir hsterlzeide ATTORNEY United States Patent APPARATUS FOR DISTRIBUTING MATERIAL EQUALLY BETWEEN A PLURALITY 0F ZONES Jurgeu Puhr-Westerheide, Oberhausen, Germany, assignur to The Babcock & Wilcox Company, New York, N. 12, a corporation of New Jersey Application May 17, 1954, Serial No. 430,386

3 Claims. (Cl. 51-9) This invention relates to apparatus for distributing material equally between a plurality of zones and, more particularly, to apparatus for dividing material flowing from a vertical pipe or conduit equally between a plurality of outlet pipes arranged uniformly around the vertical pipe.

While not limited thereto, the invention is particularly adapted to arrangements for cleaning the gas contacted surfaces of tubular heat exchangers. In such exchangers, heat transfer may be efiected by heat transfer from relatively hot combustion gases to metal tubes carrying relatively cooler liquids or vapors. Depending upon the characteristics of the fuel burned to produce the hot gases and upon the efiiciency of combustion, the hot gases flowing over the tubes will carry a greater or less amount of fly ash and other solids in suspension, and a proportion of these solids are deposited upon the gas contacted tube surfaces.

The thus deposited solids reduce the efiiciency of heat transfer from the gases to the tubes, and the deposits, if. not removed, may build up to an extent suflicient to bridge inter-tube spaces and at least partially block the gas passes. Accordingly, it is desirable to remove the deposited solids either at regular intervals or whenever the deposits have built up to a predetermined extent.

Soot blowing is efiective in dislodging the finer deposited solids which have not adhered to the tube surface, but is not effective to remove solidified slag from the surfaces. Various arrangements have been proposed for dislodging the adhering solids, and one effective method is to discharge relatively hard pellets, metal balls, or gravel over the gas contacted tube surfaces. The pellets may be forciblly discharged from nozzles against the tube surfaces or may be distributed above the tube surfaces to fall by gravity thereover.

In the latter case, the pellets are discharged from a centrifugal distributor rotatable about an upwardly extending axis located substantially centrally of a horizontal cross-sectional area over which the pellets are distributed to fall through a substantially vertically extending zone in which the tubular heat exchanger is arranged. In order to secure substantially uniform distribution of the pellets over the horizontal area, the distributor is preferably formed with an involute periphery so that varying radial discharge velocities are imparted to the pellets for uniform distribution thereof over the horizontal area. The pellets may be fed to the distributor through a feed conduit coaxial with the axis of rotation.

While centrifugal distributors, especially those of the involute type and those having periodically variable speed driving arrangements are effective in obtaining substantially uniform distribution of the pellets over the horizontal cross-sectional area, the mounting of movable elements in the path of hot fiue gases is undesirable from the operating and maintenance viewpoints. For this reason, and particularly with higher gas temperatures, fixed or stationary distributors are preferred.

However, such fixed distributors have a considerably smaller spread" than do centrifugal distributors, thus requiring a number of fixed distributors to cover the horizontal cross-sectional area which can be covered by one centrifugal distributor. To assure uniform distribution over the entire cross-sectional area, the pellets must be evenly divided between the several fixed distributors.

To this end, the invention arrangement includes a vertical feed pipe rotated at a constant speed and distributing the pellets uniformly around a coaxial annulus or trough. A plurality of distributor pipes are connected to the annulus at points spaced equally therearound, and each pipe is arranged to deliver pellets to a particular horizontal cross-sectional area of the heat exchanger. Due to the constant angular velocity of the vertical feed pipe, the pellets are distributed absolutely uniformly throughout the annulus, and thus divided equally between the several distributor pipes. Such equal division may be even further insured by partitioning the annulus or distribution box into equi-sized compartments each having a distributor pipe leading therefrom.

For an understanding of the invention principles, reference is made to the following description of a typical em bodiment thereof as illustrated in the accompanying drawing. In the drawing:

Fig. l is an axial sectional view, partly schematic, of apparatus embodying the invention; and

Fig. 2 is a plan view of the apparatus shown in Fig. 1.

Referring to the drawing, the invention apparatus 10 is mounted, for example, above the roof 19 of a substantially vertically extending zone, such as a vapor generator gas pass containing one or more tubular heat exchangers (not shown). For example, 19 may be the roof of the gas pass shown in Fig. 4 of my copending application Serial No. 315,304, filed October 17, 1952, now Patent No. 2,762,610, issued September 11, 1956. The apparatus is designed to distribute pellets, such as gravel or steel balls for example, uniformly over a horizontal cross sectional area of the vertically extending zone.

Apparatus 10 includes a vertically disposed collecting or feed pipe or cylinder 20 which is rotatably mounted in a vertical cylindrical sleeve 11 by means of bearings rings 12, 12. The upper end of pipe 20 has secured thereto a V-belt pulley 21 driven by a V-belt 13 from a V- belt driving or output pulley 16 of a suitable driving means, such as a geared electric motor 15.

A thrust bearing 14, disposed between pulley 21 and a bushing 17 in the upper end of sleeve 11, supports the weight of pipe and pulley. A cylindrical shroud 18 attached to pulley 21 protects bearing 14 against fouling by foreign matter.

The pellets are delivered to the upper end of pipe by a pipe 22 connected to a pipe or conveyor 23 which returns pellets collected in a hopper or the like at the bottom of the vertical zone through which the distributed pellets fall by gravity. The pellets fall through pipe 20 against deflector means 24 which directs the pellets to a lateral opening 25 adjacent the closed bottom 26 of pipe.

The bottom end of pipe 20 extends through a central opening in the top or cover plate 31 of a distributor hous ing 30. Pipe 20 extends sufficiently into housing so that opening 25 is fully inside the housing. A flange 19 on the lower end of sleeve 11 is secured by bolts 32 to plate 31.

Housing 30 may be polygonal but is preferably cylindrical, and includes a cylindrical outer wall 33 welded or otherwise secured to depend from the periphery of top plate 31. Within the housing, and coaxial therewith, is a replaceable central body including a conical top 34 and a cylindrical skirt 36, Skirt 36 and wall 33 cooperatively form an annulus 35. Nipples 37 having flanges 38 are secured to annulus at points equi-spaced around the annulus. Flanges 38 are secured to flanges 41 on stationary distributor pipes 40 each arranged to distribute pellets over an equal fraction of the total horizontal cross-sectional area to be covered.

Two angle iron frames 42 secured to plate 31 by bolts 43 support motor 15 and carry brackets 44 supporting return conveyor 23.

Due to the constant uniform angular velocity of pipe 20, the pellets are uniformly distributed along the annulus 35 so that each pipe 40 receives the same number of pellets. If, for constructional reasons, pipes 40 cannot be connected in a uniform manner to annulus 35, a uniform distribution of pellets can be effected by inserting parti tions 45 into the annulus to assure an even division of pellets between the several pipes 40.

The compact arrangement of distributor 10 requires little space, while the distributor is visible and easily accessible. Since it is outside the gas pass, the moving parts are not alfected by the high temperature and solids content of the heating gases.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Apparatus for distributing material substantially uniformly over subdivisions of a horizontal cross-sectional raea of a substantially vertically extending zone comprising, in combination, a housing including an annular top wall and a relatively large diameter cylindrical side wall;

a central body within said housing including a relatively 30 large diameter cylindrical skirt and a conical top peripherally congruent with the upper end thereof, said skirt being coaxial with and of less diameter than said side Wall to form with the latter an annulus having parallel vertical walls; a plurality of distributor pipes connected to equi-spaced points around said annulus and each leading to a different one of such subdivisions; a rotatably mounted relatively small diameter feed pipe extending through said top wall coaxially of said annulus to adjacent the apex of said conical top, said feed pipe having an open upper end for discharge of material thereto, a tluscd lower end and an opening in its side wall adjacent said closed lower end; and driving means connected to said pipe above said top wall for rotating said feed pipe at a constant angular velocity to distribute material uniformly around said annulus for even division between said pipes.

2. Apparatus as claimed in claim 1 including means dividing said annulus into compartments each connected to one of said distributor pipes.

3. Apparatus as claimed in claim 1 in which said feed pipe is mounted on bearings in a sleeve concentric with the opening in said top wall and has its lower discharge end disposed beneath said top wall.

References Cited in the file of this patent UNITED STATES PATENTS 339,566 Longsdon Apr. 6, 1886 2,547,794 Stone Apr. 3, 1951 2,625,305 Conkling Jan. 13, 1953 2,665,118 Broman Jan. 5, 1954

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