EP2070670A1

EP2070670A1 - Device and method for manufacturing perforated green bricks from clay

Info

Publication number: EP2070670A1
Application number: EP08021440A
Authority: EP
Inventors: Wilhelmus Jacobus Maria Kosman
Original assignee: Beheermaatschappij De Boer Nijmegen BV
Current assignee: Beheermaatschappij De Boer Nijmegen BV
Priority date: 2007-12-10
Filing date: 2008-12-10
Publication date: 2009-06-17
Anticipated expiration: 2028-12-10
Also published as: ATE487576T1; DK2070670T3; ES2354641T3; DE602008003392D1; EP2070670B1; NL1034806C2

Abstract

The present invention relates to a device (1) for manufacturing green bricks from clay for the brick manufacturing industry, comprising: a circulating conveyor (2) formed from mould container parts (3), wherein each mould container part (3) comprises one or more mould containers (16), means (4) for arranging deformable clay in the mould containers (16), and means for discharging green bricks released from the mould containers, wherein the device further comprises two parts (20,22) movable relative to each other, the first part (20) comprising at least one hollow perforating member (34) for arranging a recess in the clay, wherein the hollow perforating member (34) comprises open outer ends on both sides, and the second part (22) comprising holding means (40) adapted to hold the green brick in place when the clay is perforated out of the green brick.
The invention further relates to a device for removing clay from a green brick, and to a method for manufacturing green bricks from clay.

Description

The present invention relates to a device for manufacturing green bricks from clay for the brick manufacturing industry, comprising a circulating conveyor formed from mould container parts, wherein each mould container part comprises one or more mould containers having in each case a mould cavity, means for arranging deformable clay in the mould cavities of the mould containers, and means for discharging green bricks released from the mould containers.
The invention further relates to a perforating device for removing clay from a green brick, and to a method for manufacturing green bricks from clay.
For environmental, energy-related and cost-related reasons attempts are being made in all branches of industry to save material, thus also in the brick manufacturing industry.
The brick manufacturing industry can be divided into so-called extruders, in which clay is extruded, and so-called mould chain presses.
Extruders produce a kind of sausage of clay which is then cut to the desired brick size. Such extruders have the advantage that the mould through which the clay is pressed can be provided relatively easily with a form such that perforations will be present in the final brick, this resulting in a material-saving. However, because the clay is pressed like a sausage through the mould, for instance the outer surface of the brick has been exposed to shear stresses which have an adverse effect on the aesthetic aspects of such a brick.
In so-called mould chain presses, to which the present invention relates, deformable clay is pressed in mould cavities - usually covered in sand - of mould containers. The green brick formed in the mould container is then released in order to be dried and fired. The advantage of such mould chain presses is that the aesthetic aspects are improved. There is moreover the option in mould chain presses of manufacturing, in mechanical manner, so-called 'hand-moulded' bricks which show a visual likeness to bricks made in the traditional handmade way. Material-saving in mould chain presses has however remained limited up until now to the arranging of protrusions, so-called frogs, in the mould containers, whereby less clay is required to fill the mould container.
It is desirable to realize a further material-saving in mould chain presses, so that bricks can be manufactured which require less clay but still have the aesthetic advantages of bricks manufactured with a mould chain press.
An object of the present invention is to provide a device and method for manufacturing green bricks from clay for the brick manufacturing industry with which it is possible to remove clay from a green brick.
Said object is achieved with the device for manufacturing green bricks from clay for the brick manufacturing industry according to the present invention, comprising:

a circulating conveyor formed from mould container parts, wherein each mould container part comprises one or more mould containers having in each case a mould cavity;
means for arranging deformable clay in the mould cavities of the mould containers; and
means for discharging green bricks released from the mould containers;
wherein the device further comprises two parts movable relative to each other;
the first part comprising at least one hollow perforating member for arranging a recess in the clay, wherein the hollow perforating member comprises open outer ends on both sides; and
the second part comprising holding means adapted to hold the green brick in place when the clay is perforated out of the green brick.

Because the device comprises two parts movable relative to each other, clay can be perforated out of the green brick while the desired brick shape is retained. While the first part perforates a recess in the clay with a perforating member, the second part, using holding means, holds in place the green brick from which the clay is being removed. The shape of the green brick is hereby retained, and the green brick is particularly prevented from being deformed as a result of shear forces between the perforating member and the clay when the perforating member is moved out of the clay. Without holding means this would normally result in protruding shapes along the periphery of the perforated holes.
Because the perforating member is a hollow body with open outer ends on both sides, in particular a hollow tube, the perforating member is able to allow passage of removed clay. Such a hollow perforating member is therefore able, in the limited cycle time of a mould chain press - which is generally about two seconds per stroke -, to perforate recesses in the green bricks.
Because the hollow perforating member comprises open outer ends on both sides, it is possible to dispense with alternative measures for removing the clay from the perforating member. According to such an alternative measure, clay which is received in the perforating member can for instance be pushed out of the perforating member by means of a plunger on the mould container side. However, in order to prevent the clay falling onto the green bricks present in the mould container a time-consuming intermediate step must be performed. A first option comprises of temporarily positioning a collecting device under the perforating member for the purpose of collecting the clay removed from the green brick. A second option comprises of displacing the perforating member to a position above a collecting device for the purpose of collecting the clay removed from the green brick.
Both the above stated options require an intermediate step which cannot be realized in the cycle time of an operational mould chain press, and would therefore slow the cycle time, which is undesirable. In addition, the above stated options require additional installation space for the purpose of displacing either the perforating member or the collecting device. Owing to its complexity, the required mechanical construction will moreover need more maintenance than the device according to the present invention, and also consume energy each time the perforating member or the collecting device is displaced between each press stroke.
Although any cross-section can be envisaged, curved shapes without corners have the advantage that clay can be more easily removed therefrom, this simplifying cleaning operations.
If the perforating member were not given a hollow form, it would displace the clay at the position of the perforating member when pressed into the green brick, whereby a recess is also made in the green brick. The use of such a non-hollow member functioning as displacing means does however require a very precise dosing of the clay in the mould container, and is therefore undesirable.
It is noted that the recess can comprise a hole all the way through the green brick as well as a blind hole therein. The clay removed from the green brick results in a material-saving, this being desirable for environmental, energy-related and cost-related reasons.
Because the surface area exposed to the hot air in the drying chamber is enlarged, the green bricks can moreover be dried in a short drying time, or optionally at lower temperature.
According to a preferred embodiment, the device further comprises at least one spring which is arranged between the first and second part and which is adapted to press the holding means against the mould container when the perforating member is situated at least partially in the mould container.
This means that the perforating member is situated at least partially in a volume enclosed by the mould container, also referred to as mould cavity. This mould cavity of the mould container is intended to receive and shape a green brick. Because the spring presses the holding means against the mould container while the perforating member removes clay from the mould, the mould cavity of the mould container is bounded on the top side by the holding means, whereby the shape of the green brick is retained when the clay is removed.
According to a further preferred embodiment, the device further comprises a frame comprising two parts movable relative to each other, wherein the frame can be arranged above the mould container in which one or more green bricks are received such that the frame with the movable parts is movable relative to the mould container, wherein the perforating member arranged on the first part is displaceable at least partially in the mould container for the purpose of perforating clay out of a green brick received in the mould container.
Displaceable in the mould container means that the perforating member is displaceable into the mould cavity of the mould container in which the green brick is being formed.
According to a further preferred embodiment, the holding means comprise a plate provided with at least one opening through which the perforating member is movable. Because the perforating member can move through the plate, clay can be taken out of the green brick while the plate holds the green brick in place around the perforating member.
According to yet another preferred embodiment, the holding means are covered with felt. Covering the contact surface between the holding means and the clay of the green brick with felt can reduce adhesion of the clay to the holding means. It should be noted that other options for preventing adhesion can also be envisaged, such as chemical solutions, the applying of an electric charge and covering the contact surface with sand.
According to yet another preferred embodiment, the device is further provided with supply means for supplying fluid to the felt. The adhesion of clay to the holding means can be reduced still further by moistening the felt layer with a fluid, such as for instance oil, in particular biodegradable oil, but also mineral oil. The felt layer moistened with oil prevents adhesion of the clay to the plate.
According to yet another preferred embodiment, the mould container is provided with at least one air feed opening. These air feed openings are arranged in the bottom of the mould cavity to prevent a vacuum occurring when the clay is removed from the green brick, which vacuum would prevent or impede removal. The openings are therefore situated at the locations where the recesses are arranged in the green bricks, i.e. in the line of the stroke of the perforating member. In addition, an extra air feed opening can be provided close to the edge of the mould container in order to facilitate release of the green brick from the mould container.
By embodying the bottom of the mould containers in a material which is to at least some extent elastic, for instance rubber, the perforating member can be pressed firmly through into the bottom, thereby forming a complete perforation through the green brick.
According to yet another preferred embodiment, the perforating member is driven hydraulically or pneumatically, this having the advantage that a preset force can be exerted at the lowest point. This is much more difficult to realize with a purely mechanical drive.
According to yet another preferred embodiment, the hollow perforating member is received at its outer end remote from the mould container side in a collecting body on which clay carried through the hollow perforating member can be collected. The perforating member removes a portion of clay at a time from a green brick, so that in the case of a hollow tubular perforating member cylindrical pieces of clay will be present in the perforating member. When the perforating member is filled with fresh clay from the mould container side, cylindrical pieces of clay already present in the perforating member will be pushed through until they leave the perforating member on the outer end remote from the mould container side. The clay is collected on the collecting body close to this outer end and subsequently discharged for reuse.
According to yet another preferred embodiment, the collecting body is at least partially plate-like, and the open outer end of the hollow perforating member remote from the mould container side is received in the plate-like collecting body, wherein a discharge device is further provided for discharging from the plate-like collecting body clay collected thereon. The discharge device comprises for instance one or more plates driven via a conveyor which displace off the collecting body the clay collected on the collecting body.
The open outer end of the hollow perforating member is preferably received at least substantially close-fittingly in the plate-like collecting body.
The present invention further relates to a device for removing clay from a green brick, comprising two parts movable relative to each other, wherein the first part comprises at least one hollow perforating member with open outer ends on both sides, wherein the perforating member serves to arrange a recess in the clay, and wherein the second part comprises holding means adapted to hold the green brick in place when the clay is removed from the green brick.
In a preferred embodiment of the perforating device the two parts movable relative to each other are received in a frame which can be arranged above a mould container in which one or more green bricks are received.
In a further preferred embodiment of the perforating device the mould container forms part of a device for manufacturing green bricks from clay for the brick manufacturing industry.
The present invention further relates to a method for perforating clay out of a green brick, comprising the following steps of:

placing a device for removing clay from a green brick, as described above, above one or more green bricks formed from deformable clay in mould cavities of mould containers;
displacing in the direction of the mould container in which the green brick is received the first part comprising at least one hollow perforating member with open outer ends on both sides, wherein the perforating member is pressed into the clay of the green brick received in the mould container;
moving the perforating member out of the clay of the green brick, wherein the perforating member takes away clay removed from the green brick; and
wherein the second part with holding means holds in place the clay of the green brick received in the mould cavity of the mould container when the perforating member is moved out of the clay.

In a preferred embodiment of the method the removed clay is pushed through the hollow perforating member by successive perforating movements of the perforating member until it leaves the perforating member at the open outer end remote from the mould container side. Fresh clay is removed at each subsequent perforating movement. This pushes the clay already present in the perforating member, and which has been removed during previous perforating movements, further until it is pushed out of the perforating member.
In a further preferred embodiment of the method the clay which leaves the perforating member at the open outer end remote from the mould container side is collected on a collecting body.
In yet another preferred embodiment of the method the clay collected on the collecting body is discharged by a discharge device.
Preferred embodiments of the present invention are further elucidated in the following description with reference to the drawing, in which:

Figure 1 is a perspective view of a device for manufacturing green bricks from clay for the brick manufacturing industry;
Figure 2 is a perspective view of a device for perforating recesses into green bricks;
Figure 3 is a cross-sectional view of a part of the perforating device shown in figure 2;
Figure 4 is a side view of the perforating device shown in figure 2;
Figure 5 is a side view of a part of the perforating device shown in figure 4 in a first position;
Figure 6 is a side view of a part of the perforating device shown in figure 4 in a further advanced position;
Figure 7 is a side view of a part of the perforating device shown in figure 4 in an even further advanced position;
Figure 8 is a side view of a part of the perforating device shown in figure 4 in an even further advanced position;
Figure 9 is a side view of a part of the perforating device shown in figure 4 in an even further advanced position;
Figure 10 is a side view of a part of the perforating device shown in figure 4 in an even further advanced position;
Figure 11 is a cut-away perspective detail view of a mould container;
Figure 12A is a sectional view of a holding plate with felt in a first embodiment; and
Figure 12B is a sectional view of a holding plate with felt in a second embodiment.

Device 1 for manufacturing green bricks for the brick manufacturing industry comprises a chain conveyor 2, also referred to as a mould conveyor. This chain conveyor 2 is assembled from a large number of connected mould container parts 3, comprising in each case a number of mould containers 16. Shown in figures 1 and 2 is a so-called 16-container mould conveyor, which means that mould container parts 3 are provided in each case with sixteen mould containers 16. Each mould container 16 comprises a mould cavity 23 (figure 11) in which clay can be received for the purpose of forming a green brick 18. Mould container parts 3 are mutually coupled and provided with rollers 15 rotatable over girders 14 in order to together thus form the chain of chain conveyor 2 - or mould conveyor. The chain is driven by one of the chain wheels 13 or by both chain wheels 13 (wherein for the sake of clarity only the right-hand chain wheel is shown in figure 1). The transporting direction of the chain conveyor is to the left in the embodiment shown in figure 1 (P1 in figure 1). A conveyor rotating to the right is of course equally possible.
Placed above mould containers 16 is a reservoir 4 for clay which is kept in continuous movement by an agitator 5 which is driven by motor 6. Clay is fed ¬to reservoir 4 by a circulating conveyor 7. The clay is carried out of reservoir 4 into mould container 16 and then pressed down by a pressing device 8 which is pivotable around a shaft 9. The excess clay is also trimmed using means which are not drawn.
The device 1 comprises a further conveyor 10 with which take-off plates 11 are supplied. Conveyor 10 also ensures that a take-off plate 11 is placed on top of each passing mould container part 3. Take-off plates 11 remain pressed against the respective mould con¬tainer parts 3 by a holding mechanism 12 when they pass over the left-hand chain wheel (not shown) on the discharge side of the device. After turning over of the mould container part 3, the green bricks 18 still lie on plates 11. A knock-out mechanism (not shown) presses the green bricks 18 out of mould containers 16 per mould container part 3. Green bricks 18 herein remain lying on plates 11 after they have been released from mould containers 16. Plates 11 with green bricks 18 thereon are then discharged for further treatment, such as drying and firing.
Figure 2 is a perspective view of a perforating device 19 for perforating into green bricks 18 recesses 46 which are arranged at the position of the box indicated in figure 1.
Perforating device 19 comprises a frame 24 which is adjustable in height direction H and which comprises two parts 20, 22 which are movable relative to each other and which are connected to frame 24 by means of beams 26. First part 20 comprises a part 28 open to the top and having a U-profile built up of a bottom plate 30 and upright walls 32. First part 20 further comprises a perforating member 34 in the form of a hollow tube with open outer ends on both sides. Second part 22 is connected to first part 20 by means of rods 36 which act as guide. Arranged round rods 36 is a compression spring 38 which presses holding plate 40 of second part 22 away from first part 20. Arranged in holding plate 40 are openings 42 through which the perforating member connected to first part 20 can be moved. Holding plate 40 is further provided with a felt layer which reduces adhesion of the clay of green brick 18 to holding plate 40.
In figure 2 the transporting direction of the mould conveyor is indicated with arrow P1, wherein green bricks 18 are shown on the left-hand side in figure 2 which have already been moved through under perforating device 19 and have therefore been provided with recesses 46.
One layer of clay at a time is perforated out of a green brick 18 in perforating device 2. This removed layer of clay is received each time as a piece of clay 48 in perforating member 34. When perforating member 34 is filled with fresh clay from the mould container side, pieces of clay 48 already present in perforating member 34 are pushed through the hollow perforating member 34 with open outer ends on both sides, as can be seen in figures 2 and 3.
Perforating device 19 of figure 2 further comprises a discharge device 60 consisting of a shaft 62 on which chain wheels 64 are arranged. Chain wheels 64 drive a conveyor 66 with plates 68 for the purpose of discharging clay collected on bottom plate 30 (figure 2).
Figure 4 shows that perforating device 19 is driven by a crank mechanism 70 comprising length-adjustable arms 72. By varying the length of arms 72 the starting position of the stroke of perforating device 19 can be adjusted. In this way perforating device 19 can be set to the desired brick thickness, such as for instance 'Waal' variety size or 'Thick Waal' variety size, without the length of the stroke having to be modified. It is not therefore necessary to adjust the arm of crank mechanism 70.
A further elucidation of the functioning of perforating device 19 will now be given with reference to figures 5-10. In figure 5 perforating device 19 is situated above mould container 16 in which a green brick 18 is received.
When perforating device 19 is displaced in the direction of mould container 16 (indicated with the arrow), holding plate 40 is pressed with its felt layer 44 against mould container 16 and the green brick 18 received therein (figure 6).
When perforating device 19 is then pushed further downward, perforating members 34 move through openings 42 in holding plate 40 (figure 7). Perforating members 34 are pushed into the clay of green brick 18 situated in mould cavity 23 of mould container 16, wherein perforating members 34 perforate a portion of the clay. Spring 38 is compressed when second part 22 of perforating device 19 supports against mould container 16 and first part 20 of perforating device 19 is moved further downward.
When first part 20 and second part 22 of perforating device 19 then move apart again (figure 8), perforating members 34 move out of green brick 18. The clay 48 removed by perforating members 34 is co-displaced with perforating members 34 out of green brick 18, wherein recesses 46 are formed in green brick 18. Arranging air feed openings 56 in the bottom part of mould container 16, which part is formed by ejecting member 54, prevents a vacuum being created when the clay 48 is pulled away from green brick 18, which vacuum would impede removal of the clay. It is noted that the air feed openings in figures 5-10 are shown schematically only as channels, while in figure 11 they are shown in the form of a cross.
As perforating members 34 move out of green brick 18, spring 38 provides sufficient downward pressure on holding plate 40 in the direction of mould container 16 that the clay of green brick 18 is held in place.
Once perforating members 34 have been wholly removed from green brick 18, the distance between second part 22 and first part 20 of perforating device 19 is such that spring 38 no longer presses holding plate 40 onto mould container 16, and is moved in upward direction away from mould container 16 together with the whole perforating device 19 (figure 10).
In the cut-away perspective view of a mould container 16 it can clearly be seen that an ejecting member 54 forms the bottom of mould cavity 23 of mould container 16. Air feed openings 56 are arranged in this bottom at the locations where the hollow perforating members 34 will arrange recesses 46 in green brick 18 in order to prevent a vacuum being created when the removed clay 48 moves with perforating members 34 out of mould cavity 23 with green brick 18.
Figures 12A and 12B show two embodiments in which the felt 44 can be arranged on holding plate 40. In both embodiments the felt protrudes at least locally through holding plate 40 so that it can be moistened from the top side with supply means 50 for supplying a fluid 52 such as oil. The moistened felt 44 on the top side of holding plate 40 will become saturated and thus also moisten the felt 44 on the underside of holding plate 40, this reducing the adhesion of clay.
Although they show preferred embodiments of the invention, the above described embodiments are intended only to illustrate the present invention and not to limit the scope of the invention in any way. It is particularly noted that the skilled person can combine technical measures of the different embodiments. The scope of the invention is therefore defined solely by the following claims.

Claims

Device for manufacturing green bricks from clay for the brick manufacturing industry, comprising:
- a circulating conveyor formed from mould container parts, wherein each mould container part comprises one or more mould containers having in each case a mould cavity;

- means for arranging deformable clay in the mould cavities of the mould containers; and

- means for dis¬charging green bricks released from the mould containers;
characterized in that the device further comprises two parts movable relative to each other;
- the first part comprising at least one hollow perforating member for arranging a recess in the clay, wherein the hollow perforating member comprises open outer ends on both sides; and

- the second part comprising holding means adapted to hold the green brick in place when the clay is perforated out of the green brick.
Device as claimed in claim 1, further comprising at least one spring which is arranged between the first and second part and which is adapted to press the holding means against the mould container when the perforating member is situated at least partially in the mould container.
Device as claimed in claim 1 or 2, further comprising:
- a frame comprising two parts movable relative to each other;

- wherein the frame can be arranged above the mould container in which one or more green bricks are received such that the frame with the movable parts is movable relative to the mould container, wherein the perforating member arranged on the first part is displaceable at least partially in the mould container for the purpose of perforating clay out of a green brick received in the mould container.
Device as claimed in any of the foregoing claims, wherein the holding means comprise a plate provided with at least one opening through which the perforating member is movable.
Device as claimed in any of the foregoing claims, wherein the holding means are covered with felt.
Device as claimed in claim 5, wherein the device is further provided with supply means for supplying fluid to the felt.
Device as claimed in any of the foregoing claims, wherein the mould container is provided with at least one air feed opening.
Device as claimed in any of the foregoing claims, wherein the perforating member is driven hydraulically or pneumatically.
Device as claimed in any of the foregoing claims, wherein the hollow perforating member is received at its outer end remote from the mould container side in a collecting body on which clay carried through the hollow perforating member can be collected.
Device as claimed in claim 9, wherein:
- the collecting body is at least partially plate-like; and

- the outer end of the hollow perforating member remote from the mould container side is received in the plate-like collecting body; and

- wherein a discharge device is further provided for discharging from the plate-like collecting body clay collected thereon.
Method for perforating clay out of a green brick, comprising the steps of:
- placing above one or more green bricks formed from deformable clay in mould cavities of mould containers a device for removing clay from the green brick comprising:

- two parts movable relative to each other;

- the first part comprising at least one hollow perforating member for arranging a recess in the clay, wherein the hollow perforating member comprises open outer ends on both sides; and

- the second part comprising holding means adapted to hold the green brick in place when the clay is perforated out of the green brick;

- displacing in the direction of the mould container in which the green brick is received the first part comprising at least one hollow perforating member with open outer ends on both sides, wherein the perforating member is pressed into the clay of the green brick received in the mould container;

- moving the perforating member out of the clay of the green brick, wherein the perforating member takes away clay removed from the green brick; and

- wherein the second part with holding means holds in place the clay of the green brick received in the mould cavity of the mould container when the perforating member is moved out of the clay.
Method as claimed in claim 11, wherein the removed clay is pushed through the hollow perforating member by successive perforating movements of the perforating member until it leaves the perforating member at the open outer end remote from the mould container.
Method as claimed in claim 12, wherein the clay which leaves the perforating member at the open outer end remote from the mould container is collected on a collecting body.
Method as claimed in claim 13, wherein the clay collected on the collecting body is discharged by a discharge device.
Method as claimed in any of the claims 11-14, wherein a device is applied as according to any of the claims 1-10.