Method and vibratory chute for treating goods

Manufactured goods such as cast components to which molding sand is still adhering, are treated in a vibratory conveyor chute for cleaning and cooling the goods. As the goods travel down the chute they are exposed to force components extending perpendicularly and across to the travel direction along the length of the chute. These force components impose on the goods a revolving motion along a helical path. This revolving motion may be improved or intensified by directing the resulting force components (R, R') of the force causing the revolving motion to extend at a spacing from a so-called "center of gravity line" (S, S') defining or interconnecting the center of gravity points along the length of the vibratory chute system. This spacing causes a distribution of the goods (11) in the chute such that the goods (11) have a slanted surface (10) in the chute (1). Thus, the vertical acceleration values (k.sub.v) are larger at the upper return zone 26 than they are at the lower return zone 27. This type of treatment combined with the conveying movement is applicable to various kinds of goods and treatment procedures.

BACKGROUND OF THE INVENTION 
The invention relates to a method for treating of goods in a vibrating 
conveyor chute, especially for cleaning and cooling of cast components to 
which the molding sand still adheres. In this method vibration or force 
components are produced which extend substantially perpendicularly and 
across the main conveying direction along the longitudinal axis of the 
chute. The invention also relates to a vibrating conveyor chute for 
performing the present method. 
In connection with known devices for treating of goods in a vibrating 
conveyor chute a type of helically revolving motion is achieved for the 
goods being treated in the conveyor chute which is excited or rather 
vibrated substantially in directions perpendicularly and across its 
longitudinal axis. In such a chute the resultant of the vibration 
generating force is effective in a plane extending perpendicularly to the 
longitudinal axis of the chute. However, it is also possible to generate 
energizing components in the longitudinal direction of the chute, namely, 
in the main feed advance direction for transporting the goods being 
treated in the main feed advance direction. 
U.S. Pat. No. 3,053,379 (Roeder et al) discloses a material handling 
vibrating apparatus in which the vibration causing force components extend 
through the so-called total center of gravity of the apparatus. This type 
of vibrating or oscillating drive has substantial advantages for conveying 
and/or screening flowable solid materials. However, there is room for 
improvement where, in addition to the conveying and screening function, 
materials must be physically separated from each other, for example where 
molding sand needs to be separated from cast components. 
German Patent Publication (DE-OS) 2,853,344 (Scharmer) laid open on June 
19, 1980 discloses a vibratory chute for cleaning and cooling cast 
components to which mold sand is still adhering. In this prior art chute, 
which has a circular or semi-circular cross-section, the vibration 
generating force components are directed perpendicularly to and across the 
feed advance direction. The resultant force component extends through the 
center of the chute and hence is not most effective for its intended 
purpose of separating the mold sand from the cast components. 
OBJECTS OF THE INVENTION 
In view of the above it is the aim of the invention to achieve the 
following objects singly or in combination: 
to vibrate goods in such a way that different components of the goods may 
be separated from each other even if these components initially adhere to 
one another, for example sand adhering to cast components; 
to increase the effectiveness of vibrating conveyor chutes for their 
intended purpose; 
to provide a vibrating conveyor chute in which the vibration generating 
force components or rather the resultant of these force components is so 
directed that the operating conditions of the chute are taken into 
account, such operating conditions including, for example the type of 
material or materials being treated, the required or desired conveying 
speed and so forth; and 
to cause the goods in the chute to follow a flow pattern as determined by 
the size and direction of said force components. 
SUMMARY OF THE INVENTION 
It has been found that the revolving movement or the intensity of the 
movement in the conveyor chute may be substantially improved if the 
effective direction of the resultant of the energizing or vibration 
generating force is so selected that it extends with a spacing from a 
center of gravity line of the conveying system. This center of gravity 
line generally is a line which interconnects all the gravity centers of 
cross-sectional planes extending perpendicularly to the fixed central, 
longitudinal axis of the chute. The center of gravity line may shift its 
position depending on the load in the chute and on the movement of the 
load in the chute. The invention takes this into account, whereby it is, 
for example, possible to generate by means of linear vibration generators 
an especially practical and advantageous motion of the goods being treated 
in the conveyor chute. 
In the system of the invention higher vertical accelerations, so-called 
k.sub.v -values, are achieved in the upper zone of the flow of goods 
through the chute than in the lower chute zone. Thus, the goods being 
treated are influenced especially advantageously in each zone of the 
chute. In this connection the k.sub.v -value is the ratio of the vertical 
chute acceleration component to gravity. 
The effective direction of the resultant of the vibration generating force 
components is suitably adapted to the respective operating conditions 
including the type of the treatment and/or to the type of the goods to be 
treated. The filling degree of the chute is advantageously selected to be 
within the range of 10 to 50% by volumne of the chute. 
The vibration generators and/or the connecting elements for these 
generators are so constructed in a vibrating conveyor chute of the 
invention for performing the method according to the invention that the 
effective direction of the resultant of the vibration generating force 
components has a spacing to a center of gravity line of the conveyor 
system lying in the longitudinal direction of the chute. As a practical 
matter the vibration generator and/or energizing weights are arranged in a 
position adjustable manner so that the effective direction of the 
energizing or generating force components is variable. An electrical 
adjustment of the effective direction is also possible, for example, with 
the aid of autosynchronizing circular exciters. 
Vibration exciters suitable for the present purposes are disclosed in the 
above mentioned U.S. Pat. No. 3,053,379 and may be purchased as standard 
shelf items from Carl Schenck AG, D-6100 Darmstadt 1, Federal Republic of 
Germany. 
It has been further found to be practical to arrange a baffle means either 
rigidly or adjustably at the end of the conveyor chute or upstream, as 
viewed in the feed advance direction, of a screen section incorporated 
into the conveyor chute. This feature maintains the distribution of the 
goods in the chute cross-section of the conveyor chute over the length of 
the chute. The upper edge of the baffle means may in this embodiment 
suitably be constructed in accordance with the slope of the surface of the 
layer of the goods. 
Further advantageous embodiments are achieved in that the baffle means are 
equipped with a flange extending in the feed advance direction or in that 
the baffle means are constructed in steps extending opposite to the feed 
advance direction whereby the risers face toward the input end of the 
conveyor chute which may have a semi-circular, a circular, a tubular, or 
an angular cross-section or it may have a polygonal cross-section. 
Further, the conveyor chute may be arranged horizontally in the feed 
advance direction or it may have a positive or negative slant in the feed 
advance direction. 
It has been found that the method and vibrating conveyor chute according to 
the invention are well suitable for cooling and cleaning of cast 
components to which molding sand is still adhering. Especially larger 
chute constructions having a chute radius larger than about 0.5 m are 
suitable for this purpose. The method and the vibrating conveyor chute 
according to the invention are suitable for a large number of industrial 
processing and treatment procedures, such as mixing, separating, cleaning, 
heating, drying, cooling, and similar operations.

DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS AND OF THE BEST MODE 
OF THE INVENTION 
FIG. 1 shows a side view of a vibratable tubular conveyor chute 1 in a much 
simplified form. FIG. 1 is a view in the direction of the arrow A in FIG. 
2 showing a sectional view through such a chute. The tubular chute 1 is 
supported by support bearings or brackets 2, 3 and springs 4, 5 on a 
foundation 6 or on a frame. The conveyor chute 1 is driven by two 
vibration generators 7 and 8 and by means of a driving mechanism such as a 
motor 9 controllable by control means 10 of the type disclosed in the 
above mentioned U.S. Pat. No. 3,053,379. 
Support brackets 2', 3' and springs 4', 5' are also arranged on the 
opposite side as shown in FIG. 2. Control means 10 provide for 
electrically adjusting the effective direction of the vibration generating 
force components. Linear vibration energizers or directional vibration 
energizers are preferably used for this purpose. The vibration energizers 
or generators 7, 8 produce vibrations or force components perpendicularly 
and across the main feed advance direction. Stated differently, these 
vibration or force components extend perpendicularly or across the 
longitudinal chute axis "x". As a result, a non-symmetric distribution of 
the goods 11 is achieved in the chute 1 as best seen in FIG. 2, whereby 
the surface 12 of the goods 11 extends at a slant to the horizontal. The 
layer of goods 11 or rather the distribution of the goods in the chute is 
shown in FIG. 2. 
The chute of FIG. 1 is equipped with an input 13 forming a hopper type 
inlet into which the goods 11 are charged in the direction of the arrow 
14. The chute 1 is further equipped with an outlet 15 which may have a 
slanting top portion 16 and a slanting bottom portion in the form of a 
screen 17 through which one component of the goods such as sand may be 
discharged as indicated by the arrow 18. 
Other good components such as cast components may be discharged through the 
outlet 15 as indicated by the arrow 19. A baffle means 20 may be arranged 
just upstream of the outlet screen 17. The baffle means 20 may have a top 
flange 21. Further details of the baffle means 20, 21 will be described 
below. 
The main feed advance direction of the chute body 1' extends from the inlet 
13 to the outlet 15 along the central axis "x". The movement of the goods 
11 through the chute body 1' will be described in more detail below. The 
vibration generators or exciters may be adjustable in their position 
relative to the chute body 1' as indicated by the double arrows 22 in FIG. 
2. Screws 23 shown only symbolically in FIG. 2 may be used for this 
purpose. 
Due to the forces which are effective across the longitudinal chute axis 
"x" a helix type revolving motion of the goods to be treated is generated 
in the flow of the goods 11 in the conveyor chute as shown in FIG. 2 by 
two arrows 24, 25. The goods being treated are first moved corresponding 
to the direction of the energizing force along the chute bottom outwardly 
and upwardly as indicated by the arrow 24. Due to the chute shape and due 
to the movement of the goods across the longitudinal chute axis x, a zone 
26 is formed in the goods which is referred to as the upper reversing zone 
26 in which the movement direction of the goods being treated across the 
main feed advance direction is reversed. Thereafter, the goods are moving 
substantially in the upper layer of the goods toward the center of the 
chute or rather downwardly as indicated by the arrow 25. In the lower zone 
27 the movement direction is again reversed and the goods now travel again 
outwardly and upwardly, mainly near the bottom of the chute as indicated 
by the arrow 24. 
FIG. 3 illustrates the forces effective on the vibrating conveyor chute 
according to the invention. The drawing shows the cross-section of a 
circular chute body 1', equipped with a vibration generator or exciter 28 
having position adjustable weights 29, 30. Such weights may also be part 
of the exciters of FIGS. 1 and 2. The vibration generator 28 produces 
vibration or force components F.sub.h and F.sub.v in the horizontal and 
vertical directions respectively. The resultant R of the energizing force 
components F.sub.h and F.sub.v extends according to the invention with a 
spacing "s" from a mass center of gravity line S of the conveyor system. 
The line S extends perpendicularly to the plane of the drawing and in the 
longitudinal chute direction of the axis "x". The energizing forces extend 
primarily in a plane extending perpendicularly to the longitudinal chute 
axis "x". As mentioned above, the generators may also produce force 
components extending in the longitudinal chute direction or in the main 
feed advance direction if necessary. 
The goods 11 are distributed non-symmetrically in the bottom portion of the 
chute cross-section as indicated in FIGS. 2 and 3. The surface 12 of the 
layer of goods 11 extends at a slant relative to the horizontal. 
The vibration generator or exciter 28 may be arranged on the lower left 
side of the chute 1 instead of on the right side, whereby a 
mirror-symmetrical arrangement would be achieved as compared to the 
illustrated arrangement of FIG. 3. It is also possible to arrange the 
vibration exciter 28' on the upper side of the chute as indicated in 
dashed lines in the upper left hand part of FIG. 3. The vibration exciter 
28' produces in this instance horizontal and vertical force components 
F'.sub.h and F'.sub.v. The resultant R' of these energizing force 
components F'.sub.h and F'.sub.v extends again with a spacing "s'" from 
the mass center of gravity line S'. In connection with the vibration 
generator arrangement shown in dashed lines again the same or a similar 
distribution of the goods over the cross-section of the chute is achieved 
with a slant of the surface 12 of the goods 11 as indicated in FIG. 3. 
It should be mentioned here, that the goods being treated in a vibrating 
conveyor chute generally have only a small influence on the position of 
the mass center of gravity lines S or S' of the conveyor system. This 
applies particularly if the filling degree of the vibrating conveyor chute 
is relatively low. 
According to the invention the vibration generators 28 or 28' are arranged 
as shown schematically in FIG. 3 and the position of these generators 28, 
28' is such that the effective direction of the resultant R, R' of the 
vibration exciting force extends with a spacing "s" or "s'" from a mass 
center of gravity line S, S' of the conveyor system, said spacing s, s' 
resulting in a crank action, whereby vibration and rotational movements 
are imparted simultaneously to the chute and larger k.sub.v -values are 
achieved in the upper movement direction reversing zone 26 of the layer of 
goods 11 than in the lower zone 27. This means that the goods 11 being 
treated are exposed to higher vertical accelerations in this upper zone 26 
than in the lower zone 27 of the layer of goods 11. Accordingly, the 
resultant force effective on the goods being treated has a lower angular 
inclination relative to the horizontal in the lower zone of goods than the 
resultant of the energizing force R. Thus, in the upper zone 26 the 
inclination or slant is larger. The simultaneous vibrating and rotational 
motions of the chute result in an especially advantageous revolving motion 
or movement of the goods being treated and an intensive and uniform mixing 
of the goods are achieved. The rotational motions of the chute are 
indicated by double arrows 31, 32 in FIG. 3. 
It has been found to be advantageous to select the k.sub.v -values in such 
a manner that at the upper reversing zone 26 the values are larger than 
about 2.0 and that at the lower reversing zone 27 the values are larger 
than about 1.0. 
The k.sub.v -values at the upper reversal zone 26 or rather, the 
differences between the k.sub.v -values at the upper and lower reversal 
zone become the larger, the larger the spacings "s" and "s'" of the 
resultants R, R' of the exciting forces from the mass center of gravity 
line S, S' becomes. Since such spacing is adjustable according to the 
invention by conventional means such as the motor control means 10 or by 
changing the relative position of the exciter, the movement of the goods 
may be controlled most advantageously. 
The adjustment of different effective directions of the exciter force or 
forces and thus of said spacing s, s' may be realized in different ways by 
respective structural features. The generators themselves or the 
connecting elements 23 for connecting these exciters to the conveyor chute 
may be constructed to be adjustable so that the angle of inclination of 
the exciters or generators relative to the longitudinal chute axis x may 
be varied. For this purpose it is possible to use intermediate connector 
pieces or adaptors of conventional construction. It is also possible to 
shift the generator and thus the effective direction of the exciter force 
in parallel to a predetermined, given position or direction. 
Where unbalance generators are employed it is possible to adjust the 
position of the unbalance weights 29, 30. In connection with, for example, 
autosynchronizing circular exciters it is possible to employ an electrical 
adjustment. Such circular exciters are electrically controlled by 
conventional control means 10 in such a manner that the effective 
direction of the exciter force is varied. Similar mechanically effective 
adjustment devices are also known in the art, for example, in the form of 
position adjustable weights. The effective direction of the exciting force 
may be adjusted by means of these electrical and mechanical adjustment 
devices even during the operation of the vibrating conveyor chute. 
FIG. 4 shows a view of the discharge end of a tubular vibrating conveyor 
chute body 1'. The above mentioned baffle means 20 is installed near the 
output 15, 16, 17 of the vibrating conveyor chute body 1'. The baffle 
means 20 may, for example, have the form of a baffle plate which closes 
off a portion of the cross-sectional area of the chute. If desired, the 
baffle plate may extend at a right angle relative to the axis x or it may 
have a slight inclination in the direction of the feed advance, please see 
also FIGS. 1 and 5. The baffle means may be installed in a fixed manner 
or, for example, it may be adjustable in its height or in its angular 
position as indicated by the arrows 33 and 34 in FIG. 5. The adjustment 
means are conventional. A motorized adjustment during the operation is 
also possible if the baffle means is constructed and supported by means 
known for such a purpose. The position of the baffle means 20 or of its 
upper edge 21 is adapted to the position or rather the slant shown at 12 
in FIGS. 2 and 3 of the flow of goods 11 in the conveyor chute. Thus, the 
upper edge 21 extends at a slant relative to the horizontal corresponding 
about to the surface 12 of the flow of goods which establishes itself in 
the chute. The upper edge may also be curved. The stepwise construction 35 
of the baffle means 20 as shown in FIGS. 4 and 5 provides risers 36, 37 
facing toward the input 13 or against the feed advance direction in the 
chute. The baffle means 20 make sure that the distribution of the goods 
remains about the same over the cross-section of the chute and over the 
entire length of the chute. 
The baffle means 20 shown in FIG. 5 comprises a top edge 21 forming a 
flange, sill, or collar extending toward the output 15. The flange forms a 
type of support surface for larger components of the goods being treated 
which faciliates the discharge of such components over the baffle means 
20. A similar effect is achieved by the step type construction 35 of the 
baffle means 20 which extends opposite to the main feed advance direction. 
Due to these steps the goods being treated, for example, cast pieces, are 
gradually and slightly lifted in the feed advance direction of the chute 
toward the output 15 to thereby facilitate the discharge of the goods, 
especially of larger components of the goods in the direction 19. 
In a vibrating conveyor chute intended for cleaning and cooling of cast 
components to which molding sand is still adhering, and which is equipped 
with a screen section 17 at the output for separating the cast components 
from the sand, the baffle means 20 is arranged upstream of the screen 
section 17 as shown in FIG. 5. The screen section 17 may form an integral 
portion of the bottom of the chute. In connection with such a vibrating 
conveyor chute a conduit 38 with spray heads 39 for spraying the goods 
being treated, for example with water, is suitably so arranged that 
substantially the zone of the goods near the upper reversing point 26 may 
be sprayed, please see FIGS. 1 and 2. Thus, it is possible to 
substantially avoid the direct spraying of the cast components. In other 
instances it is possible to achieve a uniform moistening of the goods 
being treated if the upper zone of the goods is being sprayed. 
The vibrating conveyor chute according to the invention may be constructed 
as a tubular chute as shown, for example, in FIGS. 2 and 3 or it may have 
a semi-circular cross-section as shown in FIG. 6. However, the chute 
cross-section may also have a tubor trough shape or the chute 
cross-section may be of a polygonal configuration as shown in FIG. 8. It 
is also possible to provide a chute having substantially at least two 
plane surface members arranged to include an angle relative to each other 
as shown in FIG. 7. In any of these embodiments it must be assured as 
described above, that a cross-motion of the goods being treated is 
possible as indicated by the arrows 24 and 25. The chute may be open or it 
may be closed. 
The vibration generators or exciters may be of various constructions, for 
example directional exciters, circular exciters with enforced 
synchronization, magnetic exciters, crank drives and other suitable 
exciters may be employed, as for example described in said U.S. Pat. No. 
3,053,379. 
The conveyor chute 1 may be arranged horizontally in the longitudinal 
direction of the chute axis "x" as shown in FIG. 1. However, the chute may 
also be arranged with a positive or negative slant relative to the feed 
advance direction. If the chute is arranged horizontally, it is necessary 
that the vibration generators produce force or exciter components 
effective in the main feed advance direction. This is not necessary when 
the chute falls in the feed advance direction as shown in FIG. 9 because 
in that case the goods being treated will be transported in the main feed 
advance direction by the gravity force component. If the chute rises in 
the feed advance direction as shown in FIG. 10, then the energizing 
component must be large enough in the rising direction so that the gravity 
force component is overcome and so that simultaneously a feed advance 
motion is accomplished in the main feed advance direction. 
Although the invention has been described with reference to specific 
example embodiments, it will be appreciated that it is intended to cover 
all modifications and equivalents within the scope of the appended claims.