Apparatus for handling bodies of generally cylindrical configuration

Cylindrical bodies 12 are brought into end-to-end relationship on a conveyor 30 (FIG. 7) by means of a second conveyor 42 running at a different speed, which may be greater than or less than the speed of conveyor 30. The conveyor 42 serves to flip misorientated bodies (see FIGS. 6C, 6D) into an orientation in which their axes are parallel to the feed direction C of the conveyor 30. A modified arrangement (FIG. 10) is described for bodies with length to diameter ratios of the order of 0.8:1. Other handling devices are also described for effecting single streaming of bodies starting from a randomly distributed array (FIG. 1), for separating bodies of different sizes from each other (FIGS. 2 and 3) and for transferring bodies from one conveyor to another (FIGS. 4 and 5).

FIELD OF THE INVENTION 
This invention relates to apparatus for handling bodies of generally 
cylindrical configuration. The invention is particularly, but not 
necessarily exclusively, applicable to the handling of nuclear fuel 
pellets, the term "nuclear fuel pellets" being used herein in a loose 
sense to include, in addition to pellets of fissile material, pellets of 
other materials having nuclear characteristics, e.g. fertile and/or 
neutron-absorbing materials. 
BACKGROUND OF THE INVENTION 
One problem encountered in the nuclear fuel manufacturing industry is that 
of automatically forming the pellets, after for example compaction and 
sintering, into a stack or column with the pellets in end-to-end alignment 
with or without spaces between the pellets. 
FEATURES AND ASPECTS OF THE INVENTION 
According to the present invention there is provided apparatus for handling 
bodies of generally cylindrical configuration comprising: 
(a) means for conveying the bodies in serial fashion along a predetermined 
path, the conveying means being arranged to support the bodies in one or 
other of two stable modes, a first mode in which the body is contacted by 
the conveying means at different points around its generally cylindrical 
surface such that the body axis extends generally parallel to the 
direction of conveyance and a second mode in which the body is contacted 
by the conveying means at both its cylindrical surface and one of its end 
faces such that the body is supported in tilted fashion with its axis 
extending laterally of the direction of conveyance; and 
(b) reorientating means disposed at at least one position along the path of 
conveyance for contacting those bodies (if any) in said second mode of 
support while allowing those bodies in said first mode of support to 
remain in that mode. 
Preferably the or each re-orientating means includes a moving 
body-contacting element having a component of velocity in said direction 
of conveyance which differs from that of the conveying means, i.e. the 
body-contacting element may have a component of velocity in said direction 
of conveyance which is less than or exceeds that of the conveying means. 
The moving element is conveniently arranged to be available constantly for 
contact with bodies in the second mode of support. The moving element may 
be in the form of a driven endless element having a body-contacting run 
extending alongside and generally parallel to the conveying means. 
Preferably the or each orientating means is arranged to exert a progressive 
lifting action on the bodies during the contact phase between the bodies 
and the re-orientating means and for this purpose the or each 
re-orientating means may be arranged to contact the lowermost extremities 
of said bodies. 
In a preferred embodiment, there are first and second re-orientating means 
disposed in succession in the direction of conveyance. 
The first and second re-orientating means are preferably preceded by first 
and second means respectively for changing the angle of tilt of those 
bodies in the second mode of support, the first tilt-changing means being 
arranged to effect a tilt in one sense and the second tilt-changing means 
being arranged to effect a tilt in the opposite sense. 
Each tilt-changing means may comprise an obliquely inclined surface which 
progressively approaches said conveying means in the direction of 
conveyance for contact with those bodies in the second mode of support, 
the surface preceding the first re-orientating means being inclined in the 
opposite direction to that preceding the second re-orientating means. 
The conveying means conveniently comprises a pair of spaced generally 
parallel endless suports which form a generally horizontal conveyor run 
and serve to support said bodies therebetween in at least said first and 
second modes, said supports being driven at substantially the same speed. 
The supports may comprise endless wires, belts or the like entrained 
around pulleys. 
According to another aspect of the invention there is provided apparatus 
for handling bodies of generally cylindrical configuration, comprising 
means for channelling a two dimensional distribution of said bodies into a 
stream in which the bodies are arranged in serial fashion, the channelling 
means comprising conveying means for feeding the bodies in a predetermined 
direction and first and second channelling walls which converge in said 
predetermined direction and are arranged to intercept the bodies as they 
are fed in said predetermined direction, the first and second channelling 
walls converging together to provide an exit opening through which said 
bodies can pass one at a time only, at least one of the channelling walls 
or part thereof being movable in such a way that, on contact with bodies 
accumulating in the region of the exit opening, reverse feed motion is 
imparted to such bodies to assist free flow of the bodies through the exit 
opening. 
The movable wall may be constituted by one run of an endless belt conveyor 
arranged with its belt substantially perpendicular to the support surface 
of said conveying means. The body-contacting side of the belt is 
conveniently toothed. 
According to another aspect of the invention there is provided apparatus 
for handling bodies of generally cylindrical configuration and adapted to 
discriminate between bodies having dimensions above and below a 
predetermined value, the apparatus including conveyor means for feeding 
the bodies in serial fashion, means for locating the bodies alongside one 
edge of the supporting surface of said conveying means and separating 
means comprising a surface spaced inwardly of said one edge in such a way 
that bodies having a diameter or diameters above a predetermined value are 
rendered unstable and fall off said conveying means whilst those having a 
diameter or diameters less than said predetermined value remain stable and 
remain supported by said conveying means. 
The marginal edge portion along which the bodies are located may, in the 
vicinity of said separating means, be inclined downwardly in a direction 
away from said edge.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Although not limited thereto, the following description is given with 
specific reference to the handling of cylindrical nuclear fuel pellets 
from unloading of the pellets from a sintering boat, following passage 
through a pellet sintering furnace, through to organising the pellets into 
end-to-end alignment in preparation for subsequent processing or handling 
operations such as pellet diameter grinding, loading of the pellets onto 
grooved storage trays and, possibly direct loading of the pellet sack into 
the tubular cladding or fuel can. 
For passage through the sintering furnace, the pellets are loaded in layers 
into a molybdenum boat and adjacent layers are separated by trays which, 
in turn, are spaced apart by clindrical molybdenum spacers which are 
approximately 20% larger dimensionally than the pellets following pellet 
shrinkage during sintering. On completion of the sintering stage and 
cooling, the pellets along with the spacers are deposited on to a 
generally horizontal conveyor belt 10 (see FIG. 1). At this stage, the 
pellets and spacers (both depicted by reference numeral 12 in FIG. 1) are 
more or less randomly orientated and spread across the width of the belt 
10 with some components lying on their sides and some standing on their 
ends. The conveyor belt 10 is bordered along its edges by side walls 14, 
15. 
The belt 10 feeds the randomly orientated array of pellets and spacers 
towards and through a pellet-streaming zone from which the pellets and 
spacers emerge as a single stream. This is effected by means of a 
jam-breaking conveyor belt 16 which is entrained around pulleys 18 so as 
to extend obliquely across the path of travel of the pellets/spacers. One 
of the pulleys is driven by a motor (not shown) so that the belt 16 
travels in the direction indicated by arrows B, i.e. with the upstream run 
20 of the belt 16 travelling generally in the opposite direction to the 
direction of pellet spacer feed. The angle of inclination of the belt 16 
relative to feed direction A may, if desired be adjustable and its outer 
face may be toothed or otherwise suitably profiled. 
The belt 16 is spaced from the side wall 14 to define a gap through which 
the pellets/spacers may only pass one at a time. Any tendency for the 
pellets and spacers to jam at the apex of the cone formed between the 
sidewall 14 and the conveyor belt 16 is overcome by the counter-travel of 
the belt run 20 since this serves to set up a recirculatory motion of 
pellets and spacers in the vicinity of the gap through which the pellets 
and spacers are intended to pass. If desired, the gap between which the 
pellets pass may be defined by a pair of jam-breaking conveying belts, 
both conveniently being inclined to the direction of travel of the main 
conveyor belt 10. 
Following single-streaming, the pellets/spacers are fed to a pellet-spacer 
separating zone (see FIGS. 2 and 3) at which the sidewall 14 is 
interrupted while the pellets/spacers are displaced laterally of the feed 
direction A by a guide 22 and the belt 10 is tilted or, alternatively the 
edge of the belt 10 is caused, by wedge-shaped former 24, to slope 
inwardly (see FIG. 3) in such a way that the smaller dimensioned pellets 
12A can remain on the belt 10 but the larger dimensioned spacers 12B 
topple off the belt 10 and through hole 26 for collection and re-use in 
boat-loading. FIG. 3 shows the pellet 12A and spacer 12B with their axes 
parallel to direction A but the arrangement is such that the same effect 
(i.e. spacers toppling, pellets remaining on the belt) is obtained whether 
the pellets/spacers lie on their sides or stand on their ends. Reference 
numeral 28 depicts a presser bar for assisting the belt 10 to conform with 
the former 24 as the belt edge passes over the latter. If desired, a 
deflector may be provided on the guide 22 at a height above the belt which 
allows the pellets to pass without contact with the deflector but which 
contacts the larger dimensioned spacers and deflects them off the belt 10 
and through the hole 26. 
Following traverse of the pellet-spacer separating zone, the pellets 12 
continue to be fed by the belt 10 in the direction A to a pellet-transfer 
zone (see FIGS. 4 and 5) in which the pellets are transferred from the 
belt 10 onto a conveyor 30. The transfer is effected by guiding the 
pellets 12 to the edge of the belt 10 by means of guide 32 to such an 
extent that the pellets topple off the belt 10 immediately above the 
conveyor 30 and hence fall onto the belt 30 for further feed in the 
direction C. 
The conveyor 30 comprises a pair of spaced, parallel co-extensive wires 34 
looped around pulleys (not shown) to form upper and lower conveyor runs, 
the upper run only being shown since this is the pellet-conveying run. The 
spacing between the wires 34 is such that the pellets can be supported in 
a number of stable (or quasi-stable) positions as shown in FIGS. 6A-6E. 
The desired position is that of FIG. 6E in which the axis of the 
cylindrical pellet is parallel to the feed direction C, i.e. the wires 34 
contact the pellet along its cylindrical surface only. The positions of 
FIGS. 6C and 6D can arise and are substantially stable positions in which 
one wire 34 contacts the cylindrical pellet surface 36 while the other 
wire contacts the pellet end face 38. The positions of FIG. 6A and 6B are 
less stable and, in practice because of vibrations inherent in the 
conveyor drive, the pellets in these attitudes soon topple into the more 
stable attitudes of FIGS. 6C and 6D. If necessary, a vibratory device may 
be included to ensure this. 
The objective is to bring all of the pellets into end-to-end relation, i.e. 
with each pellet having the attutude of FIG. 6E. This is achieved by 
flipping the pellets having the attitudes shown in FIGS. 6C and 6D to that 
of FIG. 6E by means of an element with respect to which the conveyor 30 
has a relative velocity in the direction C. As shown in FIGS. 7 and 8, the 
element is constituted by the upper run 40 of an endless conveyor belt 42 
entrained around pulleys 44, one of which is a drive pulley arranged to 
drive the belt in the direction indicated by arrows D in FIG. 7. The upper 
belt run 40 is caused, by stripper block 46, to follow a path in which it 
progressively approaches the conveyor 30 from underneath, then reaches a 
plateau in which it runs parallel to conveyor 30 with the belt of conveyor 
42 located between the wires 34 and thereafter inclines downwardly from 
the conveyor 30. 
Over the length of the plateau section, the upper surface of the run 40 is 
at a level, with respect to the conveyor 30, such that the run 40 contacts 
the lowermost extremities of pellets in the attitudes of FIGS. 6C-6E and 
lifts the pellets to a small degree without causing them to topple off the 
conveyor 30. Such contact between the run 40 and pellets having the 
desired attitude of FIG. 6E will leave the pellet orientation unchanged. 
However, in the case of pellets having the attitudes of FIGS. 6C and 6D, 
such contact will (by virtue of the differential velocity existing between 
the belt 40 and the conveyor 30) result in a slight lifting and turning 
action being imparted to such pellets thereby flipping them into the 
desired attitude of FIG. 6E. 
The velocity of the belt 42 may advantageously be greater than that of 
conveyor 30 (typically a 2:1 ratio) over the plateau region since the 
flipping action of the pellet is then accompanied by an acceleration in 
the direction C thereby creating a gap between successive pellets to 
accommodate the greatest dimension (i.e. along a diagonal) of the flipped 
pellet. However, it is feasible for the velocity of the belt 42 to be less 
than that of the conveyor 30 (e.g. 1:2) and still result in a flipping 
action if the pellets are suitably spaced. 
The embodiment of FIGS. 7 and 8 is intended for the case where the pellet 
length to diameter ratio is somewhat greater than unity (e.g. 1.1:1 or 
greater). Where the pellet length to diameter ratio is somewhat less (e.g. 
0.8:1) a modified approach is necessary as will now be explained. 
Referring to FIGS. 9A and 9B, these show the stable attitudes 
corresponding to FIGS. 6C and 6D but for a shorter pellet. With a shorter 
pellet, the pellet end face 38 tends to be less inclined to the horizontal 
than the pellet cylindrical surface 36. For successful flipping of the 
pellets to occur, the shorter pellets need to be tilted about the point of 
contact between the wire 34 and the pellet cylindrical surface in a 
direction which decreases the inclination of the cylindrical surface 36. 
The modified arrangement of FIGS. 10, 11 and 11A is designed to cater for 
shorter (as well as longer) pellets. In this arrangement, two conveyors 
42A, B are employed each of which may be as described with reference to 
FIGS. 7 and 8 and each is preceded by a pellet-tilting former 48,50 which 
serve respectively to tilt the pellets in the attitudes of FIGS. 9A and 9B 
into orientations in which the pellet cylindrical surfaces 36 are less 
steeply inclined so that these surfaces (rather than the pellet end faces) 
are more predominantly presented towards the belt runs 40 as the latter 
approach their plateau regions. Thus the former 48 tilts the pellet 
attitude of FIG. 9A in a clockwise direction while the former 50 tilts the 
pellet attitude of FIG. 9B in a counterclockwise direction. In this way, 
the first conveyor 42A in conjunction with the former 48 is instrumental 
in flipping shorter pellets having the FIG. 9A attitude into the desired 
attitude (see FIG. 6E) while the second conveyor 42B, in conjunction with 
the former 50, flips pellets having the FIG. 9B attitude to the desired 
attitude.