DE4140012A1 - Vibratory material-compacting press - has chamber above plate kept at lower vacuum than that below - Google Patents

Abstract

The vibratory press compacts mixtures of materials in moulds temporarily supported on a fixed surface in it. It has a thrust plate moved downwards from the rest position and coupled to a vibrator mechanism of adjustable frequency. A bell-housing also lowered into the working position has a first chamber in which an adjustable vacuum is generated, and forms a seal for the mould and plate in all positions. A second vacuum chamber (A) above the plate (20) is kept at a lower vacuum than the first (B), and which is maintained during the entire duration of the operation in which that in the first chamber is maintained. USE/ADVANTAGE - Improved sealing and working conditions.

Description

The present invention relates to the production of Slabs and blocks of granular, stony or ceramic materials, and in particular an improved Press for use in the shaping phase of the raw or "green" product before curing by drying or burning in the oven. Manufacturing has been for decades of artificial imitation products for natural stones (Marble, granite, porphyry, etc.) without the disadvantages and Limits on the manufacture of panels, blocks and accompanying other products made of natural stones, a goal of technical research.  

In recent years, i.e. H. since 1975, has been a technique conceived, developed and made ready for use, which the Use of stony or ceramic materials in granular or rather small-sized to produce the products in question.

The main advantage of this technique occurs in its fullest Evidence comes to light when you consider that the use of natural stones regularly no more than 35% of the material taken from a quarry during manufacture of the products in question is used so that the Operating income is very low, apart from any Environmental and ecological considerations.

In other words, every time blocks are stoned Material taken from quarries, a large one Part of the material removed unused and forms moreover an obstacle that must be removed what naturally leads to an increase in operating costs.

In the technique mentioned, to which by reference to the Material sold commercially under the name "Bretonstone" as well as on Italian Patents No. 9 12 160, 10 56 388, 11 17 346, 11 15 526 and 11 81 570 can, the stony or ceramic granular or at any rate, material crumbled into rather coarse grain sizes with a minimal amount of a cementing, ceramic or resinous binder, whereupon the Shaping of the raw product and subsequent hardening by drying if it is a cement Binder, or by catalysis and / or cooling, if it is a synthetic hard, or finally is passed over by burning if it is a ceramic binder.  

The operations to prepare the starting mix inert aggregate and binder as well as the shape are often carried out under vacuum, whereby the main goal in reducing if not eliminating the air bubbles in the raw product and thus the porosity after hardening. The shaping in turn takes place by pressing with simultaneous vibration (Vibration compression), which are also from the same mentioned reasons is carried out under vacuum.

In this last phase, it will be in a form or a Mold box-stored mixture of the action of a press exposed with a perpendicular between one raised position or rest position and one lowered position or working position movable Pressure plate is equipped with the pressure plate Means for generating a vibration movement predetermined and adjustable frequency are connected.

Of course, the compulsion causes under vacuum too work, difficulties and complications, and he forces the press plate into a bell in which the vacuum is created.

Since the first practical use of this technology there was a constant effort to control the volume of the bell reduce as much as possible, of course without that Requirement to carry out the Disregard vibration compaction operation, and it was also to avoid as much as possible that every press cycle would be necessary the vacuum in the bell again at the level required Establish operating values.  

In the industrial plants operated until today tried to limit the requirement by limiting the actual bell to a much reduced space around the Position in which the molding box or the shape is brought when this with the to be compressed and the mixture to be subjected to vibrations and above from the pressure plate of the press in their said raised position are closed. In this way concerns the alternation of vacuum and restoration of the atmospheric pressure in each work cycle only one very crowded volume, without excessive losses regarding the costs and times of operations and hence the vibration compaction cycles for a single one Product.

The top of the press plate is on Means of applying a force connected so is dimensioned so that it affects the action of the pressure on the material contained in the mold or mold box and sometimes the downward and upward movement of the Pressure plate determined. This force is preferably with With the help of pneumatic actuators supplied with Compressed air can be fed.

Nevertheless, it is clear that this solution, although in this respect is valuable when they apply the technique in question enabled on an industrial scale, not without problems and disadvantages, among which are the first to operate the named actuators in synchronism with the execution of the vacuum in the bell surrounding the mold or the mold box belongs.

In French Patent No. 20 17 343 there is one Vibration compactor described above the pressure plate of the press a sealing plate  is provided, which the interior of the Bell containing vibration compression stamp in two Chambers divided, namely an upper and a lower Chamber, both of which are connected to a vacuum source, such that the vacuum also on the material batch of Vibration compressor works.

This vacuum remains even during the final phase of the Vibration compression in the lower chamber and thus in Contact with the material while the vacuum in the upper chamber disappears.

There is another non-negligible problem in that the tightness both with respect to the actuators, as well regarding the sliding edges of the pressure plate of the press to ensure existing vacuum in the bell, namely given the fact that the environmental situation in which the press works, decidedly unfavorable and stressful is (stony or ceramic material dust, moisture with cementing binders, etc.).

Accordingly, the main object of the present invention is therein an apparatus of the type in question and for the same purposes, therefore with the same services, in With regard to the vibration compaction in the form or to create a mixture in the molding box at which the problems and disadvantages briefly identified above are substantially eliminated.

This goal is achieved with a press on Vibration compression of mixtures in molds or Molding boxes that are temporarily on a fixed level of Press, with the press one between one raised position or rest position and one  lowered position or working position vertical movable pressure plate, which is driven by means of Generation of a vibration movement predetermined and adjustable frequency is connected, as well as a bell has also between a raised position or rest position and a lowered position or Working position is movable and in which a vacuum predetermined and adjustable height is generated, the Bell forms a first chamber that is able both the shape sitting on the solid surface or the Mold box, as well as the movable pressure plate of the press to keep tight in all positions which the plate even during the labor movement and the return movement assumes the rest position, characterized in that a second vacuum chamber above the pressure plate is formed, in which a lower vacuum than that is generated that is operational at everyone Working cycle is established in the first chamber, wherein the vacuum in the second chamber under negative pressure at least during the pressing of the pressure plate and preferably for the entire duration of the Working cycle is effective, during which the vacuum in the first chamber is maintained.

As is readily apparent from the detailed below Description of a preferred embodiment of the Invention with reference to the accompanying drawings emerges from the press according to the present Invention not only the actuators and those with them related problems are eliminated but the vacuum created in The second chamber is also created for the Execution of the compression process in the form or in Forming box containing material, apart from its use to facilitate the work of the for example oleodynamically operated devices,  which the downward and upward gear of the pressure plate of the Press cause because in both cases Pressure difference builds up between the two chambers.

Below is the main subject of the drawings briefly described.

Fig. 1 shows a schematic view of the essential components of the press according to the present invention in elevation and partial longitudinal section along the line II of Fig. 2;

Figure 2 illustrates a top view of the press of Figure 1;

Fig. 3 and 4 are views similar of Figure 1 is showing the press in different operating states of the Funktionszyklusses. and

FIG. 5 shows a view analogous to FIG. 1 of an embodiment variant of the press.

Before the subject of the present invention Press described in detail should expediently be pointed out that one think of the press as being part of a facility must, for example in the invention patents no. 11 17 346 and 11 81 570 by the applicant Marcello Toncelli is described.

In this system, the output unit (marble, stony material and the like) variable particle size  together with an organic or inorganic Enter binder in a mixer group in which the Basic mix is made with the group preferably works under vacuum.

After mixing, the mass is dosed into one Form or a form box with a paper film as Intermediate layer, or poured onto a conveyor belt, then the top surface of the mixture with a second paper film is covered. In the case of The paper foils are transported through a conveyor belt Continuous paper tape replaced by a suitably arranged coil unwound. That the mix containing form or the mold box or the dosed Mixing quantities in regular intervals Conveyor belt enter the press according to the invention.

In FIGS. 1 to 4 of the case of the transported on a conveyor belt mixture is shown, while in FIG. 5 shows the case of the mixture contained in a mold or a molding box, wherein the mold is mounted on a movable on rails car.

In detail to the press according to the present invention, and in particular to the embodiment shown in FIGS. 1 to 4 embodiment, the actual press an outer bell 10 which is secured by corresponding support portions 12 of respective actuators 14 which as trimmings with cylinder 16 and piston 18 are shown and carry out and control the displacement of the pressure plate 10 in the vertical direction between two positions, each of which is shown in Fig. 1 (lowered bell or working position) and in Fig. 3 (raised bell or rest position). In the embodiment shown in Fig. 1, the bell 10 is designed as a box-shaped structure and provided with reinforcing beams that do not require any further explanation.

Inside the bell is the press plate 20 of the press, which is also vertically movable thanks to the actuators with cylinder and piston, the actuator sets being generally designated 22 and arranged at the four corners of the press plate 20 , as can be seen in FIG. 2 .

The press plate 20 is movable between two positions, each of which is shown in Fig. 1 (lowered press plate in the working or compacting position) and in Fig. 4 or 3 (raised press plate or rest position).

For the upward and downward movement of the press plate 20 , guide and reinforcing elements are provided, which are generally and collectively provided with the reference numerals 24 and 26 , and further guide plates 25 are attached, which are fastened to the bell 10 . Seals 28 secure the seal in the circumferential direction during the vertical displacement movement of the press plate 20 . The working surface of the press is identified by the reference symbol 30 and is sealed off by the lower peripheral edge 32 of the bell 10 with the aid of a seal 34 .

In the embodiment shown in FIGS. 1 to 4, the conveyor belt 36 , which, as mentioned, comes from the metering station of the mixture prepared in the mixer group, lies on the work surface 30 .

On the bell 10 projecting supports 38 are attached to the inside of the bell, at the end of which each angle elements 40 are attached, with the function of limiting the area of action of the lower working surface 42 of the press plate 20 and laterally enclosing the mixture P when it is compressive action of the press plate 20 is such that the product takes and maintains the desired shape, which is in the specific case of a plate.

The press plate 20 is connected at the upper end to means for generating a vibratory movement of the plate with a predetermined and controllable frequency. The relevant means are not shown for reasons of clarity of the drawing, especially since they do not form an integral part of the invention.

For more details, refer to the earlier cited Patents referred to the Marcello Toncelli name.

The press plate 20 divides the interior of the bell 10 into two chambers, each of which is designated by the letters A and B. The two chambers are connected in a manner known per se to a vacuum pump (not shown) which creates a vacuum of a predetermined height in each chamber.

For the sake of simplicity, the connection of chamber A to the vacuum pump is identified by reference number 44 , while the connection of chamber 5 to the vacuum pump is identified by reference number 46 .

Of course, the connections in question are with the necessary sealing and control valves.  

As regards the embodiment shown in Fig. 5, it differs from that shown in the preceding figures embodiment in that the use is provided of molds or mold boxes 48, instead of the conveyor belt 36, which are mounted on rollers 50 and run on rails 52.

Referring to the operation of the press according to the present invention, the duty cycle begins with the press operating position shown in Fig. 3, that is, a situation where both the bell 10 and the press plate 20 are in their raised position. In this state, both the chamber A and the chamber B can be under atmospheric pressure, but the vacuum or a vacuum which was established there during the course of the previous cycle is preferably also left in the chamber A. In this state, the conveyor belt 26 is moved forward by the predetermined distance until a dose of the mixture P is brought into the position centered between the angle elements 40 .

Then the bell 10 is lowered to the position shown in Fig. 4 position, but the press plate 20 remains in FIG. Raised position shown 4 in the.

In this operating state, the vacuum pump connected to the nozzle 26 is switched on, with the aid of which a rather high vacuum of the order of 50-100 mm Hg, for example, is generated in the chamber B.

Simultaneously or immediately thereafter, the vacuum pump connected to the line 44 is switched on, so that a less high vacuum than that in chamber B of, for example, 200 mm Hg compared to 100 mm Hg in chamber B is produced in chamber A.

In other words, there must always be a difference in the level of the vacuum and therefore the pressures between the chambers A and B, such that the press plate 20 is downward in the absence of supports or into the mixture for compressing the mixture on the conveyor belt 36 required direction is pushed.

The negative pressure prevailing in chamber B acts on the mixture on the conveyor belt in the manner that it extracts the greatest possible amount of air from it with the purpose of increasing the porosity of the product after firing or drying as well as the other possible defects on one Reduce minimum, which is due to the presence of Air in the mixture of the tile Can form block during manufacture.

So that the negative pressure prevailing in the chamber B shows its effect, the pressure plate 20 is lowered after a predetermined period of time and the mechanism for generating the vibratory movement of the pressure plate 20 is switched on, preferably with the aid of the actuators 22 , at the same time as the compression and actual pressing of the pressure plate Mixture P exposed to the pressure difference between chambers A and B.

At the end of the compression phase, the atmospheric pressure is restored in chamber B after the connection to the vacuum source 46 has been closed. Simultaneously with this or immediately thereafter, the upward movement of the press plate 20 begins to release the now compacted and shaped mixture P and thus to initiate the drying, firing or hardening phase, depending on the type of binder with which the initial mixture was produced. Then the bell 10 is raised.

Of course, the negative pressure existing in chamber A needs not to be changed as he goes through the different phases the working cycle does not disturb, on the contrary the Work of the lifting and lowering devices of the press plate relieved, in addition to his Primary responsibility for the compression phase and Press the mixture into the desired final shape.

In the case of the variant of FIG. 5, the mold 48 containing the metered mixture quantity passes under the pressure plate 20 and is subjected to vibration compression in the same manner as already described. Of course, in the event that the mold or the mold box 48 is to be used to produce a block instead of a plate, the corresponding dimensions and above all the distances between the press plate 20 and the working surface 30 of the press must be modified accordingly.

Finally, it should be noted that the press according to the present invention only for a preferred one Embodiment has been described, but equivalent conceptual and mechanical modifications and variations is accessible without exceeding the scope of the invention becomes.

Claims (5)

1. Press for the vibration compression of mixtures in molds or mold boxes, which are temporarily seated on a fixed plane of the press, the press having a pressure plate which is vertically movable between a raised position or rest position and a lowered position or working position and which drives the means for generating a vibration movement of predetermined and adjustable frequency is connected, and has a bell, which is also movable between a raised position or rest position and a lowered position or working position and in which a vacuum of predetermined and adjustable height is generated, the bell being a first chamber forms, which is able to keep both the mold or mold box sitting on the solid surface, as well as the movable pressure plate of the press in all positions, which the plate itself assumes during the working movement and the return movement into the rest position, thereby characterized in that a second vacuum chamber is formed above the pressure plate, in which a lower vacuum is generated than that which is produced operationally in each working cycle in the first chamber, the vacuum in the second chamber, which is under pressure, being effective during the entire working period , during which the vacuum is maintained in the first chamber. 2. Press according to claim 1, characterized in that the pressure plate on its downward and upward strokes is driven relative to the pressing surface of actuators. 3. Press according to claim 2, characterized in that the actuators from sets with cylinders and pistons for pneumatic or oleodynamic drive exist. 4. Press according to claim 1, characterized in that they are the first means of creating the vacuum in the first chamber and second means for generating the Has vacuum in the second chamber. 5. Press according to claim 1, characterized in that means equipped with cylinders and pistons Operation of the bell on the down and Upward strokes relative to the press plane.