US3263441A

US3263441A - Apparatus for cooling pressed shaped structures

Info

Publication number: US3263441A
Application number: US413907A
Authority: US
Inventors: Rother Bruno
Original assignee: G A PFLEIDERER
Current assignee: G A PFLEIDERER
Priority date: 1963-11-30
Filing date: 1964-11-25
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02
Also published as: CH417939A; GB1042419A; SE310062B; DE1201543B; AT264802B

Description

Aug. 1966 B. ROTHER 3,263,441

APPARATUS FOR COOLING PRESSED SHAPED STRUCTURES Filed Nov. 25, 1964 5 Sheets-Sheet 1 N P LE B. ROTHER 3,263,441

APPARATUS FOR COOLING PRESSED SHAPED STRUCTURES Aug. 2, 1966 5 Sheets-Sheet 2 Filed Nov. 25, 1.964

Aug. 2, 1966 B. ROTHER 3,263,441

APPARATUS FOR COOLING PRESSED SHAPED STRUCTURES Filed Nov. 25, L964 5 Sheets-Sheet 5 Fig.5

United States Patent 4 Claims. (a. 62341) This invention relates to the cooling of pressed shaped bodies or structures, such as chipboard, or plates formed of flat shavings, bagasse, etc., by means of a flowing coolant and, if required, under pressure.

The cooling of the shaped bodies leaving the heating press, having been pressed into shape at temperatures in the range of about 120185 C., is of particular importance because the sharp temperature drop accompanying it may easily lead to deformations of the shaped bodies. This danger is especially great with shaped bodies having the form of plates and the like, in particular when these have a low thickness. The percentage of rejects is corresponding high.

On the other hand, the known cooling methods involve, with regard to the space and time required, a very expensive intermediate storage of the shaped bodies between the press and the finishing steps, in order to ensure the necessarily complete hardening required by the subsequent polishing step.

In a prior proposed cooling process, the shaped bodies are clamped, just as during the preceding heating process, so that they cannot warp or be distorted during cooling. However, the sudden contact of the shaped bodies, which are still hot, with the cold cooling surfaces of the cooling press causes intensive condensation in the interior of the plate. This premature condensation, resulting from the sharp temperature drop, is very detrimental to the properties of the shaped bodies concerned, because the water vapour which serves as a carrier of the almost universally employed synthetic resin binders, plays a decisive role in the production of said shaped bodies.

Since the cooling press must operate at the same speed as the heating press preceding it, slow cooling is not possible in view of the short heating periods usual in this process.

Moreover, cooling presses of this kind are extremely expensive to purchase and to operate and require a considerable space.

The drawbacks resulting from the above expense are avoided or reduced in another prior proposed process in which the shaped bodies leaving the press are swept by a coolant fluid in a cooling canal. To achieve a correct cooling effect however, the shaped bodies have to be repeatedly displaced in this process, e.g. by rotation, being held by clamp elements. For this reason, the equipment is rather subject to breakdown; in addition, no safety is offered against warping.

The considerable disadvantages of the known arrangements make it desirable to seek new ways of cooling pressed shaped bodies, more especially chipboard or the like, which satisfy the requirements of integrating the cooling process into a largely automatic operation in the production of such shaped bodies. In particular, it is necessary to effect the cooling at a rate correspond ing to the output of the press and to conduct it according to a programme until the shaped bodies reach a state in which their finishing can be under-taken without any further intermediate working, storage or the like.

According to the invention there is provided a process for cooling pressed shaped bodies, e.g. chipboard plates, by means of a flowing coolant and if required under pressure, in which the shaped bodies leaving the press are transported in steps and are cooled in steps during the rest periods of their transport.

The process according to the invention takes into particular account the nature of the materials being processed in an especially advantageous and rational manner in that, by the stepwise cooling, a complete hardening of the shaped bodies or of their binders is achieved while avoiding detrimental condensation or like phenomena and without the danger of warping. The exploitation of the existing transport path from press to finishing, i.e. in general to squaring and/or polishing, makes it possible to reduce the temperature of the shaped bodies in a simple manner and Without additional space requirements.

The invention further provides an apparatus for carrying out the process defined above, comprising several successive pairs of coolant-irrigated cooling faces movable in relation to each other said faces being arranged to receive pressed shaped bodies from the heating press and being associated with conveyor means serving for the transport of the shaped bodies.

The arrangement according to the invention renders possible the stepwise cooling of the shaped bodies with the simplest possible means at a rate corresponding with the press output, to the value corresponding to the desired physical properties of the shaped bodies. It is further within the scope of the invention to choose the number of cooling-face'pairs according to practical requirements and to increase or reduce their number optionally.

The invention is not limited to a specific spatial position of the cooling faces. The latter may be arranged in a horizontal plane as well as in vertical or any other position, so that a maximum adaptability to existing conditions results.

If the arrangement is employed in conjunction with an installation for returning the sheet-metal forms or moulds from press to strewing machine, then the invention further provides for the cooling-face pairs to be arranged under or above the conveyor returning the sheet-metal forms. This arrangement avoids any additional spatial requirements and may utilise the structural elements of the conveyor for sheet-metal forms.

According to another feature of the invention, the cooling faces comprise coiled pipes with a flat face facing the shaped bodies, one cooling face of each pair being vertically displaceable in relation to the other. This arrangement makes possible a direct heat transfer between the cooling faces and the surfaces of the shaped bodies to be cooled, while allowing an unhindered movement of the shaped bodies along the cooling path, i.e. from the coils of one cooling-face pair to another.

The arrangement according to the invention is preferably operated counter to the flow of the coolant which is accordinglyfed in at the take-off end of the cooling path and led out at the first pair of cooling faces at the input end of the cooling path. The coolant is expediently re-circulate-d through a heat exchanger and a pump. The invention provides for the possibility of series-connecting the individual cooling coils of the faces and the pairs of faces in the direction of the flow. Accordingly, the coolant will flow through both pipe coils of a pair before entering the next pair.

On the other hand, it is also possible to series-connect separately the cooling face coils on either side of the pairs. In this arrangement, the coolant circuit is expediently divided at one end of the cooling path and is united again at the other end.

According to a further feature of the invention, the pipe coils of the cooling faces extend in the direction of the transport of the shaped bodies. However, under certain circumstances it may be expedient to have the pipes extending transversely to the direction of advance of the shaped bodies.

Mobility of the individual cooling faces of a pair is provided according to the invention by movably connecting the adjacent pipe coils of the cooling faces to each other. This movable connection is provided both between the two pipe coils of a given cooling-face pair and between adjoining pairs. Expediently, flexible pipe joints are used for this purpose.

It is further within the scope of the invention to arrange the pipe coils of successive cooling face pairs staggered in relation to each other in such a manner that a pipe interval is succeeded by a pipe on the next following pair of faces, and vice versa. This arrangement ensures that the surfaces of the shaped bodies are exposed substantially uniformly to the coolant during their passage along the cooling path.

As further provided according to the invention, conveyor elements are arranged on one side at least of the cooling-face pairs. In a horizontal arrangement of the individual cooling faces this corresponds to the lower cooling faces on which the shaped bodies rest.

In order to avoid hindering the cooling process, the conveyor elements are arranged, according to another feature of the invention, so as to be movable from an engaged position into a rest position in relation to the shaped bodies. This is to be understood as a movable mounting of the conveyor elements and also as a fixed mounting of the latter with a simultaneously movable arrangement of the cooling surfaces positioned at least on the side of the conveyor elements.

In further development of the invention, each of the cooling-face pairs is provided with at least one powered axle, extending transversely to the direction of transport, on which axles discs or similar elements are mounted so as to project into the intervals between the coolant pipe coils with their peripheries projecting beyond the plane of the cooling faces in the engaged position. When the two cooling faces of a pair are moved away from each other, the conveyor elements come into engagement with the shaped bodies and move these in the intended direction of transport into the next following coolingface pair.

In a particularly advantageous arrangement, the conveying axles of each cooling face pair have a common drive. The drive may be continuous or intermittent. It is also quite possible to give a common drive to all conveyor elements.

According to a further feature of the invention, the two cooling faces of a pair are each hingedly connected at opposite ends to two lateral pivot levers which are fixedly and substantially centrally mounted and one of which is engaged by a setting mechanism.

This results in a particularly advantageous mounting of the cooling faces of each pair, having regard to weight compensation. However, this arrangement also renders possible a fixed mounting of the conveyor elements which, when the two cooling faces move away from each other, project above the cooling faces and come into engagement with the contact surface of the shaped bodies.

Further features, details and advantages of the invention will be apparent from the following description of a preferred embodiment with reference to the accompanying drawing wherein:

FIG. 1 is a schematical plan view of an installation for producing chipboard panels or like pressed shaped bodies;

FIG. 2 is a view along the line II-II of FIG. 1;

FIG. 3 is a fragmentary plan view on an enlarged scale;

FIG. 4 is a side elevation of a section of the cooling path according to FIGS. 1 and 2, on a further enlarged scale; and,

FIG. 5 is an enlarged section on the line VV of FIG. 3.

Referring to FIGS. 1 and 2 of the drawings, the installation as a whole includes a strewing machine, indicated at 1, in the region of which the sheet-metal forms required for shaping are covered with a chip mat provided with the binder and possibly other additives. The filled shaping irons pass along conveyor 2 into a heating press designated by the reference 3, from where they are ejected in the direction of arrow 4. In the region of position 5, the pressed shaped bodies (chipboard panels in this embodiment) are removed from the sheet-metal forms here not shown in detail, by a takeoff device 6, which may for example consist of a suction plate; the sheet metal form in turn moves over conveyor 7, in the direction of arrow 8, on conveyor 9 and is moved back by means of the latter and the adjacent intermediate conveyor to the strewing machine. The only schematically indicated shaping-iron return 9 is located below cooling path designated by 11.

Shaped bodies 12 gripped individually by the transverse conveyor 6 and carried between guide rails 13 are passed to input 14 of the cooling path 11. The latter is defined by cooling faces 15 arranged in pairs one above the other; the faces 15 are formed by coolant pipe coils 16, which extend along the cooling path 11 in the direction of advance of the shaped bodies as indicated by arrow 17. At the takeoff end 18 of the cooling path 11, the coolant enters at 19 into the upper or lower pipe coil 16 of cooling-face pair 15' and, after flowing through both pipe coils 16 of this pair 15' which are connected to each other by a flexible pipe joint, passes through a further flexible connection 20 into the coils of adjacent cooling-face pair 15". The coolant progresses in this manner until it reaches the coils of cooling-face pair 15 adjacent the input 14 of the cooling path, from which it emerges at 21, and is fed to a heatexchanger 22 with a series-connected pump 23. The cooled and hardened boards then leave the cooling path at output 54 and pass to the finishing line.

FIGS. 3 and 4 illustrate a section of the path 11, namely a top view of a pair of cooling-faces 15 in the form of the pipe coils 16, the lower of which is virtually hidden by the upper one. Each pipe coil 16 is fastened to two transverse shafts 25 of which the lateral ends are mounted in rocking levers 26. Pipes 27 of the coils 16 have a rectangular cross-section and intervals 28 between these pipes are narrower than the width of the pipes. As FIG. 5 shows, bearing pin 29 of each upper shaft 25 and lower shafts 25', is attached by means of a support 30. The rocking lever 26 is mounted, on axis 38 (FIG. 3) on lateral support 31, which rests on support 32.

A flexible pipe joint between the two pipe coils 16 of the cooling-face pair 15, indicated in FIGS. 3 and 4, is shown at 33. A further flexible joint 34 constitutes the connection between each pipe coil and that of the next following cooling face.

On one of the lateral supports 31 of the cooling path 11 there is mounted a setting motor 35, an axially extensible setting member 36 of which engages at 37 the rocking lever 26'. On extending the setting member 36, all four rocking levers required for disengaging a pair of cooling faces 15 are pivoted, about their axes 38, so that faces 40 of the pipes 27 facing board 39 move away from each other, in that the upper cooling face moves upwards and the lower cooling face moves downwards from the closing position.

On transverse supports 42, connected to the longitudinal supports 31, there are mounted bearings 43 which carry shafts 44; in the present example seven shafts are provided for each cooling-face pair. Discs 45 which enter the pipe intervals 28 of the coils 16 are secured to the shafts 44. In the position shown in FIG. 5, where the two pipe coils 16 of a cooling-face pair 15 are moved away from each other so that spacing 46 is greater than the thickness of the board 39, the discs 45 project above the surface 40 of the lower coil 16 by an amount of x. Hence, the board 39 is lifted from the corresponding supporting surface 40 and rests solely on the discs 45. The discs 45 are set in rotary motion by means of motor 47 as well as by means of beltor chain-transmission 49, 48 in the direction of arrow 50, so that the boards are moved in the direction of arrow 51 (FIG. 4) and are passed on to the next following cooling-face pair.

As FIG. 3 shows, the

pipe intervals

28 or 28 of two successive cooling-face pairs 15 are so arranged that they are not aligned.

The invention is of course not limited to the form of embodiment described in the foregoing and illustrated in the drawing; rather, numerous modifications thereof are possible without deviating from the fundamental concept of the invention. Thus, for example, the installation according to the invention is by no means restricted to the production of chipboard panels, plates or like bodies; the latter merely represents a preferred field of application.

I claim:

1. Apparatus for cooling to room temperatures hot pressed articles to avoid cooling stresses and distortion therein comprising:

a plurality of pairs of superposed heat exchange members arranged in substantial alignment to define an elongated cooling path;

means for moving the heat exchange members of each pair toward and away from each other;

conveyor means extending through one heat exchange member of each pair to convey the articles from one pair to the pair next adjacent thereto, said conveyor means comprising a plurality of rotatably-driven disks which engage with the undersurface of the articles to urge them along said elongated cooling path;

and means for circulating a fluid coolant through all of said heat exchange members.

2. Apparatus as defined by claim 1 in which said heat exchange members each comprise a plurality of flat hollow conduits arranged in a serpentine configuration with the spacing between adjacent convolutions lying substantially parallel to each other and in the path of travel of the articles therealong.

3. Apparatus for cooling to room temperatures hot pressed articles to avoid cooling stresses and distortion therein comprising:

a plurality of pairs of superposed heat exchange members each comprising a plurality of fiat hollow conduits arranged in a serpentime configuration with the spacing between adjacent convolutions lying substantially parallel to each other and to the path of travel of articles therealong, so that pairs of heat exchange members being further arranged in substantial alignment with each to define an elongated cooling path;

a plurality of shafts extending transversely beneath said heat exchange members;

a plurality of discs rigidly attached to said shafts, said discs extending into the spacing between adjacent convolutions of said heat exchange members;

means for positively driving said shafts to rotate said discs;

means for displacing the heat exchange members of each pair in a vertical plane toward and away from each other whereby said discs periodically extend completely through the lower heat exchange member of each pair to engage the articles thereon and convey them to the next adjacent pair;

and means for establishing a positive circulation of fluid coolant through all of said heat exchange members.

4. Apparatus as defined by claim 3 in which said heat exchange members are connected in a closed series coolant path and in which the coolant is circulated through said members in a direction which is counter to the flow of the articles therealong.

References Cited by the Examiner UNITED STATES PATENTS 2,687,920 12/1954 Mackenzie 62-341 2,927,443 3/1960 Knowles 62341 2,993,345 7/1961 Franklin 6263 ROBERT A. OLEARY, Primary Examiner.

W. E. WAYNER, Assistant Examiner.

Claims

1. APPARATUS FOR COOLING TO ROOM TEMPERATURES HOT PRESSED ARTICLES TO AVOID COOLING STRESSES AND DISTORTION THEREIN COMPRISING: A PLURALITY OF PAIRS OF SUPERPOSED HEAT EXCHANGE MEMBERS ARRANGED IN SUBSTANTIAL ALIGNMENT TO DEFINE AN ELONGATED COOLING PATH; MEANS FOR MOVING THE HEAT EXCHANGE MEMBERS OF EACH PAIR TOWARD AND AWAY FROM EACH OTHER; CONVEYOR MEANS EXTENDING THROUGH ONE HEAT EXCHANGE MEMBER OF EACH PAIR TO CONVEY THE ARTICLES FROM ONE PAIR TO THE PAIR NEXT ADJACENT THERETO, SAID CONVEYOR MEANS COMPRISING A PLURALITY OF ROTATABLY-DRIVEN DISKS WHICH ENGAGE WITH THE UNDERSURFACE OF THE ARTICLES TO URGE THEM ALONG SAID ELONGATED COOLING PATH; AND MEANS FOR CIRCULATING A FLUID COOLANT THROUGH ALL OF SAID HEAT EXCHANGE MEMBERS.