US3447289A - Collector tube rapper system - Google Patents

Description

June 3, 1969 E. H. R. PEGG COLLECTOR TUBE RAPPER SYSTEM Filed May 8, 1967 Figure Figure 2 w in mm as R. mu ffi T m f IM A M United States Patent US. Cl. 55300 4 Claims ABSTRACT OF THE DISCLOSURE Freely swinging pendulum members are spaced along and suspended from spaced apart reciprocable rapp r bars in a parallel row arrangement with the collector tubes of a multi-type centrifugal separator unit. Each loosely hung pendulum member is actually spaced between a group of four collector tubes so that it will be capable of striking each of the four tubes in a substantially uniform manner, With two tubes receiving impact as its particular supporting bar is pulled in one direction and the other two tubes being hit as the bar is move in the opposing direction. A plurality of movable rapper bar means may all be reciprocated from a common motor operated rotating shaft.

The present invention relates to a rapping system for the collector tubes of a multiple tube centrifugal separator unit. More specifically, the present improved system utilizes loosely hung pendulum members as the rapper means in a manner such that each pendulum will strike its particular adjacent tubes in the unit with a quite uniform impact regardless of imperfect alignment or positioning of each collector tube.

It is known that in certain particle collection installations, there can be a build-up of collected material on the inside of each of the outer collector tubes of a multitube dust collector type unit. For instance, in the collection of fly ash from the burning of lignite in a steam generator, there will be fouling and plugging of the outer collector tubes of the separator unit from a build-up of collected material on the inside surfaces of these tubes. This condition will in turn cause an increase in pressure drop across the entire collector and a decrease in collection efficiency.

There have been various schemes and devices for periodically striking or rapping the tubes of a centrifugal separator unit so as to preclude excessive build-up of material in the tubes of the unit. Generally, the known prior designs have utilized rotating shafts down between the rows of tubes to effect the movement of hammers 0r rapper means adjacent each tube. Such shafts and hammer means have required numerous moving parts and bearings within a zone having a particle laden or dirty atmosphere so that as a result there has been much faulty operation and high maintenance costs. It should also be pointed out that with fixed shaft locations and fixed position rapper means there will be a tendency to have hard rapping on some tubes and light rapping on others, unless by chance there are perfect mountings and alignments of all collector tubes in a given tube sheet, as well as perfect alignment of the rapper means.

Summary of the invention It may be considered one object of the present invention to provide a rapper system which is simple to construct and mount and will accommodate itself to slight misalignment of collector tube mountings in any separator unit. It may also be considered an object of the invention to utilize loosely hung pendulums as rapper members in a system which does not require any precision bearings, and minimizes rotating members and parts of a machined nature within the dirty atmosphere of the particle collector unit.

In a broad aspect, the present invention provides in combination with a multiple tube centrifugal separator unit for a particle laden gaseous stream, Where such unit has a plurality of particle collector tubes from a common tube sheet therein, the improved rapper system in combination with the collector tubes, which comprises arranging said tubes in an even numbered plurality of rows and in a two-way manner, suspending a substantially horizontal and laterally movable rapper bar in between alternate rows of the collection tubes wherby to provide a rapper bar for each pair of tube rows in one direction, additionally hanging a plurality of freely suspended pendulum members from each of said movable rapper bars, said pendulum members being at a level and spaced laterally along each of said bars such that there are pendulum members between alternate rows of tubes with respect to the direction transverse to said bars whereby each pendulum member is available to strike the exterior wall of each of four adjacent collection tubes, positioning power driven means adjacent at least one side of said separator unit and connecting such means to each of said movable rapper bars whereby each bar is reciprocated or oscillated longitudinally and each pendulum member is caused to swing back and forth to strike adjacent tube walls in a free moving self adjusting manner.

Air cylinder units, or a motor driven shaft means, all outside of the main housing or chamber for the separator unit can well serve as the power means for linking to the movable rapper bars and there is no intent to limit the invention to one type of power system.

It should be pointed out, however, that the present system not only minimizes the problems of having bearings, gearing or moving parts within a particle laden atmosphere, but it provides for an inexpensive readily installed system that minimizes maintenance and repair problems. For example, the suspension means for the moving or reciprocating rapper bar means may be eyebolt members or punched bar stock connecting between simple pins or bolts from clip angles at the tube sheet and at the rapper bar itself. The pendulum members which in turn are supported from the reciprocating rapper bar members may be of a simple inexpensive design and need not be limited to any one particular configuration or method of fabrication. Again a simple pin or bolt member may be used to connect an upper eye-bolt portion of the pendulum to the rapper bar means. The lower portion of the pendulum may have a laterally extending plate member or other enlarged section to serve as a means for contacting and rapping the adjacent collector tubes of the plurality of particle separator tubes.

Reference to the accompanying drawing and the following description thereof will serve to illustrate one embodiment of the improved simplified rapper system of the present invention as well as point out additional advantageous features for the use of loosely hung pendulum members in such system.

Description of the drawing FIGURE '1 of the drawing shows a partial elevational view of the present improved pendulum type rapper system in combination with a plurality of collector tubes in a separator unit.

FIGURE 2 of the drawing is a partial plan View of the improved rapper system, as indicated by the line 2-2 shown in FIGURE 1.

Referring now to both FIGURES l and 2 of the drawing, there is indicated a portion of a particle collection housing 1 having a substantially horizontal tube sheet 2 for accommodating a plurality of centrifugal 3 separator devices that in turn have a plurality of outer collector tubes 3 from such tube sheet means 2. For purposes of describing the present invention, it is not deemed necessary that the separator unit inlet means, cleaned gas outlet tube means, particle collection hopper etc., be illustrated and, as a result, such details are not shown in the present drawing.

Generally, the outer particle collection tubes 3 which tend to become internally fouled or plugged with sticky materials will have lower tapered end portions 3 that in turn will feed the centrifugally separated particulate material downwardly into an enlarged collection hopper. Thus, there is somewhat greater spacings or open area between collector tubes adjacent their tapered lower portions and the pendulum members may be suspended within this zone and have greater freedom of movement in effecting the contacting of the lower portion of each tube. As best shown in FIGURE 2 of the drawing, the collector tubes 3 are arranged in a plurality of rows in a two directional manner such that horizontal and laterally movable rapper bars 4 may be arranged in one direction between alternate rows of tubes 3. Actually, in the illustrated embodiment, each raper bar unit 4 comprises two spaced apart bar members 4' which straddle their hanger bar means 6 and connect thereto by pin means 5. The bars 6 are in turn suspended from support clips or lug members 7 attached to the lower face of tube sheet means 2. Suitable bolts or pins 8 through hanger bars 6 and support means 7 serve to provide a pin connection and a resulting desired reciprocating type of movement for bar means 4.

As best shown in FIGURE 1 of the drawing, a plurality of spaced apart pendulum members 9 are attached to the reciprocating bar means 4 by bar or eye-bolt means 10 and pin means 11. These pendulum members 9 are spaced laterally along bar means 4 so as to be between every other row of tubes in the direction transverse to that of such bar means 4 and, as a result, each pendulum member 9 will serve to contact four different collector tubes 3 along their lower portions thereof 3'. The arrangement of pendulum members 9 with respect to a surrounding cluster of four collector tubes 3 is best shown in plan view by FIGURE 2 of the drawing.

It may also be noted that the positioning of the pendulum members 9 with respect to collector tubes 3 in FIGURE 2 of the drawing is such that the pendulums are in a neutral position with respect to the first two rows of tubes. However, the rapper bar member 4 and the pendulum members 9 are shown in a position such that the latter are contacting two of the four collector tubes in each grouping with respect to the third and forth rows of the unit. This positioning is accomplished by virtue of the particular arrangement of the arm means 14 from the shaft means 13 and the connection to the end of the rapper bar means 4.

As one method of operating the reciprocable rapper bar members 4, there is indicated a motor operated gear box unit 12 which connects through shaft means 13 to the crank arm means 14. The latter attaches through pin means 15 with connector bar means 16 which in turn have a pin connection 19 with the end of rapper bar means 4. The dual or spaced apart crank arm means 14 and the multiple section shaft means 13 which is held in place by suitable hearings or pillow-block means 17 will serve to carry the power from gear box 12 through the successive sections of shaft 13 across the entire width of the separator unit. Where desired, the crank arm locations on shaft means 13 may be such that all of the reciprocating bar means 4 are in a similar position; however, generally, the crank arm means 14 may be spaced at '90 with respect to successive pairs thereof such that adjacent rapper bar means 4 will be in different locations and cause a resulting striking of collector tubes by pendulum members 9 at different periods (as previously noted in connection with the location of the pendulum members 9 in FIGURE 2 of the drawing).

In the operation of the present improved unit, it will be found that the utilization of the loosely hung pendulum members 9 from the pin connections at 11 on bar members 4 will permit the pendulum to oscillate back and forth along with the reciprocating motion of the horizontal bar members 4 to which they are attached. Thus, that there is a striking of collector tubes at one side of the pendulum and then on the other regardless of misalignment of tubes or slight misalignment and positioning of bar members and their accompanying pendulums. Fro-m maintenance aspects, it will be noted that the only bearings required in the present rapper system are those which are utilized in connection with the shaft sections 13 on the housing of the separator unit and that such bearings may be actually placed outside of the collection hopper and, optionally, enclosed by a suitable weather protecting section 18. The pins or bolt means, such as 5, 8 and 11, utilized in connection between the hanger rods 6 and the rapper bars 4, as well as between pendulum rods 10 and bar means 4, may not be of any precision type of hearing or closely sized pin. Generally, loosely fitted bolts or pin members capable of making a suitable suspended connection between the inter-related parts will suffice.

In the present drawing, the enlarged portions of pendulum members 9 are indicated as being formed of circular plate-like sections held to eye-bolts or rod means 10; however, the pendulums may be of cast metal where it is found that such construction is more economical than being fabricated of separate parts. Also, in a modified design, the reciprocable horizontal rapper bar members 4 need not be of the dual bar construction comprising spaced members 4 but may be of a single rigid bar pivotally or hingedly connected to suitable hanger bar means on the side of the latter. The pendulum members are then, in turn, bolted to the side portions of such single horizontal bar means.

Although not shown, the power supply means to gear box means 12 connecting to the shaft means 13 may incorporate a time cycle controller so that there is an automatic operation causing the rapper bar system to be in motion only a portion of the time. The frequency of operation will generally be determined by the stickiness of the particulate material carrying through the separator unit and the tendency to collect on the inside of the collector tubes. At the same time, further adjustment means may be provided in the timing or cycling of the pendulum movements through the control of the gear box means 12 such that there is an accompanying variation in r.p.m. transferred to the shaft means 13. As a result, it is possible to provide a wide range of settings in the operation of the rapper system so as to suit all types of conditions for different units or for varying conditions in a particular installation.

In another method of operation, as noted briefly hereinbefore, the bar means 4 may be reciprocated by movable rods from air cylinders and there can be modification or elimination of rotating shafts and motor operated gear box means, such as 12. The design and use of air cylinders, and the like, are well known and it is not deemed necessary to illustrate an air cylinder piston rod connective with the bar means 4 or with linkage that in turn connects with an end of each bar means 4.

I claim as my invention:

1. In a multiple tube centrifugal separator unit for a particle laden gaseous stream in which a plurality of particle collector tubes depend from a common tube sheet therein, and said tubes discharge particles down into collection hopper means, said tubes being arranged in an even numbered plurality of rows and in a two-way manner, the improved rapper system in combination with said collector tubes, which comprises, a substantially horizontal and longitudinally movable rapper bar suspended in between alternate rows of the collection tubes whereby to provide a rapper bar for each pair of tube rows in one direction, a plurality of freely suspended pendulum members hanging from each of said movable rapper bars along the lengths thereof, each of said pendulum members comprising a rod member pivotally connected to its associated rapper bar and a transverse disk-like member connecting with the lower end portion of said rod member centrally located of four adjacent collector tubes whereby each of said pendulum member swings freely about a horizontal axis extending transversely with respect to its associated rapper bar and said pendulum members being at a level and spaced longitudinally along each of said bars such that there are pendulum members between alternate rows of tubes with respect to the direction transverse to said bars whereby each pendulum member is available to strike the exterior wall of each of four adjacent collection tubes, power driven means positioned adjacent at least one side of said separator unit operatively connected to each of said movable rapper bars for reciprocating each bar longitudinally and whereby each pendulum member is caused to swing back and forth in a longitudinal direction to strike adjacent tube walls in a free moving self adjusting manner.

2. The improved rapper system of claim 1 further characterized in that a power driven rotating shaft means is positioned along at least one side of said separator unit and at substantially right angles to said movable rapper bars, and arm and linkage means from said shaft means connects to each of said rapper bars whereby to reciprocate the latter.

3. The improved rapper system of claim 2 still further characterized in that adjacent rapper bars connect with said rotating shaft means through said arm and linkage means with the latter at different positions with respect to said shaft for each rapper bar whereby the pendulum members connecting to adjacent rapper bars will be in different striking positions with respect to adjacent collector tubes.

4. The rapper system of claim 2 further characterized in that adjustable power supply means connects with said rotating shaft means whereby varying rates of rotation may be given to said shaft and provide adjustment in the rapping rate from said pendulum members.

References Cited UNITED STATES PATENTS 2,192,250 3/1940 White 551 12 2,575,876 11/1951 Kausch 55296 3,394,531 7/1968 Andersen 55346 2,198,618 4/1940 Horne 55112 2,370,444 2/1945 Bowman 55348 2,438,827 3/1948 Shofiner 55348 2,702,090 2/1955 Brown et a1. 55112 3,321,892 5/1967 Saint-Jacques 55300 HARRY B. THORNTON, Primary Examiner.

BERNARD NOZICK, Assistant Examiner.

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