ZA200307336B

ZA200307336B - Plasterboard manufacturing unit.

Info

Publication number: ZA200307336B
Application number: ZA200307336A
Authority: ZA
Inventors: Charles Falinower
Original assignee: Lafarge Platres
Priority date: 2001-04-03
Filing date: 2003-09-19
Publication date: 2004-04-23
Also published as: WO2002081993A1; CN1275015C; EP1377784A1; UA74068C2; TNSN03080A1; MA26105A1; CN1500197A; FR2822746A1; FR2822746B1; RU2003132062A

Description

PLASTERBOARD MANUFACTURING UNIT

The invention relates to a plaster manufacturing unit, and more particularly a modular plasterboard manufacturing unit that can be transported by maritime container.

Plasterboard manufacturing units generally comprise a station for preparing the plaster slurry, a station for depositing the slurry on a reinforcing material, a station for forming and coating the upper surface of the slurry with another reinforcing material, a plaster hydration station, a plasterboard cutting station, a plasterboard transfer station and a plasterboard drying station, and a recutting and packaging station. The drying stations of the known manufacturing units generally comprise a combustion boiler to generate hot gases.

These manufacturing units are very complex and large in size. The installation of a plasterboard manufacturing unit in a location far from the site of manufacture of its main components requires the delivery of these dismantled components, the manufacture of other elements on the site of installation and the presence of qualified technicians to manufacture and assemble the manufacturing unit. Such installation is thus lengthy, expensive and risky.

Furthermore, the combustion boilers of these manufacturing units have a high fuel consumption for drying the plasterboards.

There is therefore a need for a manufacturing unit that can be preassembled, checked, transported and mounted on site easily, for a low cost. The invention thus proposes a plasterboard manufacturing unit comprising a hydration station, including hydration modules that connect together, a drying oven, including drying modules that connect together, it being possible for said hydration and drying modules to be able to be inserted into standard transport containers.

According to one embodiment, the hydration modules have fitting support plates suitable for joining two hydration modules together.

According to another embodiment, the hydration station includes a single drive motor.

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According to yet another embodiment, the drying modules connect together to form a tunnel through which plasterboards pass.

According to yet another embodiment, the manufacturing unit furthermore includes a distribution table that places the plasterboards in alignment with various stages of the oven.

Provision may also be made for the drying modules to be mounted so as to slide along rails.

According to one embodiment, thermal insulation panels are attached laterally and above said drying modules.

According to another embodiment, the drying oven furthermore includes a hot gas source, an indirect heating circuit, passing through the tunnel and connected to said hot gas source, and a direct heating circuit.

According to yet another embodiment, the unit furthermore includes a particle filter connected to the outlet of the indirect heating circuit, the direct heating circuit being connected to the outlet of this particle filter.

According to yet another embodiment, the manufacturing unit furthermore includes a device for recycling the gases coming from the direct heating circuit.

Moreover, it is possible to provide a manufacturing unit that furthermore includes means for driving the plasterboards through the tunnel.

According to one embodiment, the plasterboard drive means comprise rollers.

According to another embodiment, the rollers are driven by a single motor.

According to yet another embodiment, the gases from the hot gas source are introduced at a temperature of between 180 and 350 degrees into the indirect heating circuit.

According to yet another embodiment, the gases are introduced at a temperature of between 120 and 160 degrees into the direct heating circuit.

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Provision may also be made for the spacing of the rollers at the outlet of the tunnel to be greater than the spacing of the rollers at the inlet of the tunnel.

According to one embodiment, the indirect heating circuit has a plurality of tubes, one end of which communicates with and is fastened to a first header and the other end of which communicates and slides with a second header.

The subject of the invention is also a method of mounting a manufacturing unit according to the invention, comprising steps consisting in connecting hydration modules together, to form a hydration station, and in connecting drying modules together to form a drying oven.

The invention furthermore relates to a method of converting and increasing the capacity of a manufacturing unit according to the invention, comprising steps consisting in connecting additional hydration modules to the hydration station, in connecting additional drying modules to the drying oven and in increasing the drive speed of the hydration station and of the drying oven.

Other features and advantages of the invention will become apparent on reading the following description of embodiments of the invention, given by way of example and with reference to the appended drawings that show: - figure 1, a diagramatic representation of a manufacturing unit according to the invention; - figure 2, a side view of a hydration module of a manufacturing unit according to the invention; - figure 3, a front view of the hydration module of figure 2; - figure 4, a diagram showing the principle of a drying oven according to the invention; - figure 5, a sectional side view of one embodiment of a burner; - figure 6, a sectional front view of the burner of figure 5; - figure 7, a side view of a drying module for a manufacturing unit according to the invention; - figure 8, a front view of the drying module of figure 7; and - figure 9, a front view of one particular embodiment of a drying module.

The invention provides a plasterboard manufacturing unit in the form of modules that connect together easily and can be transported in standard containers.

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This manufacturing unit mainly comprises modules connected in a hydration station and modules connected in a drying oven.

The connection of modules has, in the description that follows, a broader scope than the simple fact of joining them together. This is because, it may be considered that aligned modules are connected if they cooperate to allow the transit of plasterboards.

Figure 1 shows a diagramatic representation of one example of a manufacturing unit according to the invention. The elements of this manufacturing unit 1 will be described by following the formation of a plasterboard. The plaster is prepared and formed as a wet plasterboard in the station 2. The wet plasterboard leaves the station 2 and is driven along a hydration station 3, in which the water reacts with the calcium hemihydrate. After the hydration station 3, the wet plasterboard passes via a sawing station 4, that cuts the wet plasterboard strip into plasterboards of specified dimensions. The plasterboards formed pass via a transfer station 5 that drives the plasterboards to an inclined table 21. The plasterboards are slid up to various levels in the station 6 and transferred into various levels of an oven 7. The plasterboards dry and harden on passing through the oven 7. They are placed at the outlet of the oven on a discharge device 8, in order to transport them, for example, to a resawing and packaging or finishing station. In figure 1, lines demarcate various modules of the manufacturing unit 1.

A wet plasterboard is typically formed in the station 2 by pouring plaster in the form of a slurry onto a paper web. The plaster is then covered with another paper web. This assembly is then passed, for example, into a rolling mill or an extruder in order to fix a predetermined thickness of the wet plasterboard. It is also possible thereafter to pass the wet plasterboard beneath a die, to form bevels along the edges of this wet plasterboard. The wet plasterboard then passes along the hydration station 3, generally in the form of a continuous plasterboard.

The hydration station 3 is formed from several hydration modules 9 connected together. In the example of figure 1, the hydration station has seven hydration modules 9 connected together. The hydration modules 9 serve for supporting and transporting the wet plasterboard during the hydration phase. Figures 2 and 3 show an example of a hydration module 9. Each hydration module 9 has dimensions allowing it to fit into a standard maritime transport container. Such a container typically has a length of 20 or 40 feet (i.e. 6.10 and 12.19 meters, respectively). The

R:\Brevets\18000\18034PCGB.doc - 4 septembre 2003 - 4/15 standard height and the standard width are approximately 2.28 m and 2.35 m, respectively. Preferably, a hydration module 9 will be produced so that it fits into a parallelepiped of 6 meters in length, 2.30 meters in width and 2.20 meters in height.

The hydration module 9 can thus fit into most standard containers. Thus, the 5 hydration module 9 of figure 2 has a length A of 5800 millimeters, a width B of 1600 millimeters and a height C of 830 millimeters. It is thus possible to place several of these hydration modules 9 in a container. The hydration station of figure 1, comprising seven hydration modules 9a to 9g similar to the station of figure 2, may thus be placed in four standard containers 6 meters in length.

The hydration module 9 has rollers 10 mounted so as to rotate at their ends on longitudinal members 11. The rollers 10 may, for example, be mounted on plain bearings or on rolling bearings. These rollers 10 make it possible for a conveyor belt 16 to be run with little force. These longitudinal members 11 are fastened to feet 12.

A hydration module thus typically has four feet 12. It is possible to use, for example, fastening support plates 13 for fastening the feet 12 to the floor. These fastening support plates may, for example, have a plate that bears on the floor. This plate may have a bore to allow passage of one or more fastening screws. The feet 12 may also have an adjustment device for setting the height of the rollers 10 relative to the floor.

Thus, 1t is possible to use telescopic feet whose adjustment may be set. It is also possible to use, for example, threaded feet 12 that cooperate with tappings made in the floor. The hydration modules may thus be adapted to an irregular floor.

The hydration module 9 may also have fitting support plates 14 allowing a hydration module 9 to be joined to another hydration module. The two hydration modules 9 may be joined together at their fitting support plates 14 by, for example welding, clipping or screwing of the fitting support plates. The hydration modules 9 may also be connected directly without the fitting support plates 14, for example by welding the respective longitudinal members of the hydration modules 9. It is also possible for the fitting support plates 14 to provide the electrical link between two hydration modules 9.

The wet plasterboard is conveyed by the conveyer belt 16 guided by one or more drums 17 at the far end or at the front end of the belt. The belt 16 has a large supporting surface for receiving the wet plasterboard. The wet plasterboard, which has poor mechanical properties at the start of hydration, is thus barely deformed. This belt 16 is furthermore driven by a drum 17b, which is itself driven by the motor 18.

The belt 16 slides over the rotating rollers 10 and is inserted between the wet

R:\Brevets\18000\18034PCGB.doc - 4 septembre 2003 - 5/15 plasterboard and the rollers 10. Thus, the wet plasterboard is driven by the belt 16 along the hydration station 3. A belt 1400 mm in width sliding over rollers 10 of the same length may be used. It is possible to drive the wet plasterboard only over part of the hydration station, for example by placing the belt only on the first hydration modules. It may be seen in figure 1 that the belt is used only on the first four hydration modules 9. It may then be sufficient for the wet plasterboard to run along the rollers 10 of the following modules, as shown in figure 2, if the hydration of the wet plasterboard is sufficient at this stage. It is also preferable for the motor 18, the drums 17 and the belt 16 to be dimensioned so that they can be inserted into one or more standard storage containers.

The use of hydration modules 9 readily allows the production rate of the manufacturing unit to be modified without modifying the hydration properties of the wet plasterboard. This is because it is possible to extend the length of the hydration station 3 by connecting additional hydration modules 9. It is then sufficient to increase the speed of the motor 18 in proportion to the increase in length of the hydration station 3, in order to obtain the same hydration time. A motor 18 controlled by a variable-speed drive allows the drive speed of the belt 16 to be easily modified.

It is therefore possible for the production flow in the hydration station 3 to be easily increased while maintaining the same hydration time. It is sufficient subsequently to transport to the manufacturing unit one or more containers that contain hydration modules in order to extend the hydration station 3.

After the hydration station 3, it is possible to provide a sawing station 4. This sawing station may or may not be automated and allows the wet plasterboard to be converted into plasterboards of predetermined length. This station may be produced by connecting together several sawing modules 19, similar to the hydration modules 9. This station may also be produced as a single sawing module 19. The use of rotating rollers similar to the rollers 10 allows spaces to be created between plasterboards after sawing and before entry into the transfer station 5. The dimensions indicated above for the hydration modules 9 may be used for the modules 19. These dimensions allow the sawing modules 19 to fit into most standard containers. For example, it is possible to produce the sawing station 4 by connecting together four modules 830 mm in height and 1600 mm in width. The first sawing module 19a may have a circular saw and measure 3500 mm in length. The following two modules 19b and 19¢ may have idle rollers and measure 2400 mm in length. The fourth module 19b may have rollers driven by a motor so as to transfer the

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. plasterboards. It may measure 2800 mm in length. Such dimensions allow these modules to fit into a single container.

In the installation of the manufacturing unit shown in figure 1, the manufacturing stations are arranged in a U so as to reduce the length of the unit. In this case, a transfer station 5 may be used to take the plasterboards from the sawing station 4 to the inclined table 21 or to the oven 7. The transfer station may also be produced by connecting transfer modules 20 together. These modules may be similar to the modules 9 and have rotating rollers similar to the rollers 10. These rollers have a length compatible with the dimensions of the plasterboards. The rollers of the modules 20 may be idle and in this case it is sufficient to place a plasterboard on the rollers and then push this plasterboard in order to transfer it. It is also possible to use modules 20a and 20e comprising a rotating table, for example rotating through 90°, in order to change the direction of the plasterboards that they receive. These tables may be mounted on a ram so as to modify the heightwise placement of the plaster- boards. It is also possible to drive the plasterboards in the transfer station 5 in a transverse direction of the plasterboards, using rollers, or possibly several small belts. The dimensions indicated above for the hydration modules 9 may be used for the modules 20. These dimensions allow a transfer module 20 to fit into most standard containers.

It is also possible to place a distribution table 6 in front of the inlet of the oven 7. The distribution station 6 allows the plasterboards to be placed more easily on the various stages of the oven 7. The distribution station 6 may have an inclining or elevating module 21. This inclining or elevating module may be actuated by a ram 22 or a chain. It is then possible to place a plasterboard on the module 21, then to actuate the ram 22 in order to incline or elevate the plasterboard. It is thus possible to place the plasterboard in alignment with various stages of an oven 7 or with rows of rollers 23 running respectively into one stage of the oven 7. The distribution table 6 may thus comprise a first module for transferring a plasterboard, connected to a inclining or elevating module 21 connected in turn to an oven entry module having rows of rollers 23 described above. The distribution table 6 may be made in the form of one or more modules having dimensions such as those indicated above, in order to allow them to be inserted into a standard transport container.

Figure 4 is a diagram showing the principle of an oven 7. The oven comprises a tunnel 26 formed from several drying modules 24 connected together. The tunnel 26 is supplied with hot gases via a boiler 25, and plasterboards 27 move through this

R:\Brevets\18000\18034PCGB. doc - 4 septembre 2003 - 7/15 tunnel. These plasterboards 27 move through the tunnel by means of the drive device 28. The heat generated by the hot gases in the tunnel evaporates the excess mixing water. The oven 7 described below has a double heating circuit in order to obtain better thermal efficiency. The double heating circuit described below also makes it possible to generate a stream of hot gases from the combustion of any type of fuel, while minimizing the deposition of combustion particles on the plasterboards 27. The double heating circuit has an indirect heating circuit 29 comprising tubes 36, as shown in figure 8, that is to say the gas of this circuit is not in direct contact with the plasterboards. It also has a direct heating circuit 30, that is to say the gas of this circuit follows the same path through the tunnel as the plasterboards. However, when a gas is used as fuel, it is also possible to use an oven having only a direct heating circuit.

The boiler 25 heats the gas. This gas is introduced into the indirect circuit 29 of the tunnel 26. The hot gas is introduced into the indirect circuit 29 at the optimum place for avoiding calcination of the plasterboards, typically at a point, starting from the plasterboard inlet, one-third the way along the total length of the tunnel. The gas passes through the indirect circuit and can be recovered, for example, at the ends of the tunnel. The plasterboards 27 are heated by convection of the heat from the indirect circuit into the direct circuit. The gas admission temperature is preferably set between 180 and 350 degrees. A temperature chosen within this range allows the residual water of the plasterboards to be evaporated, with low thermal energy expenditure. Furthermore, this temperature range allows standard structural elements to be used for the oven, without any risk of deterioration.

The hot gas may be generated, for example, by burning coal or a multifuel in the boiler 25. When the hot gases are generated by combustion in the boiler, it is desirable to remove the dust and other combustion waste before they are reintroduced into the direct circuit 30. The hot gas recovered at the outlet of the indirect circuit 29 is thus preferably treated by a particle filter, such as a cyclone 31.

However, it is possible not to use a particle filter, particularly when the fuel used is a gaseous fuel. The gas introduced into the cyclone 31 is centrifuged. The solid particles, such as soot, are thrown to the outside and separated from the gas. The purified gas leaving this cyclone is introduced into the direct circuit 30. Using the oven as described, it is possible to prevent the clean and generally light-colored plasterboards from coming into contact with a heating gas laden with soot and combustion residues. Moreover, the flow rate of the hot gases is preferably set at a value above 20 m/s in the indirect circuit 29 so as to limit the deposition of

R:\Brevets\18000\18034PCGB.doc - 4 septembre 2003 - 8/15 combustion soot. It is also desirable to set the flow rate of the hot gases in the direct circuit 30 at a value above 0.2 m/s so as to improve the thermal efficiency. Such flow rates may be obtained by placing suitable fans in the hot gas circuit.

Using a fuel and a suitable burner, it is also possible to use a drying station having a direct circuit supplied with hot combustion gases. It is thus possible to improve the thermal efficiency of the drying station and also reduce the complexity of this station.

The gas admission temperature of the direct circuit 30 is preferably between 160 and 120 degrees. The heat of the gases may thus be used in two heating circuits.

The thermal efficiency of the oven is thus improved. The direct heating gas is preferably removed at the ends of the oven. Removing the direct heating gas makes it possible to remove the vapor generated by evaporation of the residual water from the plasterboards. This gas may advantageously be at least partly recovered in order to be reinjected into the boiler 25. It is thus possible to use a double-drum boiler to recycle the direct heating gas.

Figures 5 and 6 show an embodiment of a boiler for recycling the hot gases drawn off, for example, at the outlet of the direct heating circuit. The boiler has a burner 50. The burner 50 has two lateral ports 51. Hot gas, represented by the arrows and coming from the direct heating circuit, is introduced into a recycling box 52 via these lateral ports 51. This recycling box 52 surrounds a combustion chamber 53.

The recycled hot gas flows from the box 52 into the combustion chamber 53. The gas 1s mixed with a fuel and burnt in order to generate gases 54 at a higher temperature.

This gas 54 is then sent into the indirect heating circuit. Of course, it is possible for the recycled hot gas to be used to reheat gas at room temperature or for the hot gas to be mixed with gas at room temperature in the burner. The thermal efficiency of the boiler is thus improved, thereby reducing the fuel consumption of the drying station.

The broken lines in figure 4 show the boundaries between the drying modules 24. An example of a drying module 24 is shown in greater detail in figures 7 and 8.

The module 24 has means for driving the plasterboards along the tunnel. These drive means here comprise rollers 32 aligned in the length direction of the tunnel. These rollers 32 are suitably spaced apart so as to allow the plasterboard to be transported without damage. It is thus possible to space the rollers 32 apart by 140 mm at the inlet of the tunnel and by 280 mm at the outlet. These rollers 32 are coupled to gears

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33 and are mounted to as to rotate relative to a support structure 34. The gears 33 may be driven by one or more chains 35 that mesh with the gears.

Each drying module preferably has several stages. Thus, it is possible to make the plasterboards 27 pass along the various stages of the oven 7 in parallel, by driving them with the rollers 32. This makes it possible to reduce the length of the tunnel 26 of the drying oven and to reduce the drive speed of the rollers.

Each drying module may also have part of the indirect heating circuit. The drying module 24 shown here has many tubes 36 attached to the support structure 34.

In the example, the tubes are arranged perpendicular to the rollers 32, that is to say in the length direction of the tunnel.

These drying modules 24 have dimensions suitable for them to be fitted into standard containers as defined above. A drying module may thus have a length of 2.10 meters, a width of 2.70 meters and a maximum height of 2.30 meters. Several drying modules may thus be easily placed in a standard container. In addition, with a drying module width greater than twice the width of a plasterboard, it is possible to place two plasterboards side by side in the oven. In the example of figure 1, the oven comprises five drying modules 24a to 24e. Two containers 6 meters in length are sufficient to transport the modules 24a to 24e with the above dimensions. Ancillary elements of the oven 7, such as the boiler 25, the roller drive motor and the cyclone 31, may be produced in the form of modules having dimensions suitable for their insertion into standard containers.

Details about the connection of the drying modules 24 forming a tunnel 26 will now be given. Each drying module 24 may have one or more support plates for its connection to another drying module. Two consecutive drying modules may be linked together for example by bolting and coupling the chains. The modules may also have means for aligning their rollers 32, so that the rollers pass correctly between the modules. They thus may have height-adjustable feet 37. It is also possible to place alignment indicators on each module, such as studs, corresponding for example to a preliminary assembly carried out at the module manufacturing site.

When the drying modules have individual heating tubes 36, it is possible for the heating tubes of successive drying modules to be connected together by a screwed link. Thus, the end of the tubes of a first drying module may be threaded and

R:\Brevets\18000\18034PCGB.doc - 4 septembre 2003 - 10/15 the end of the tubes of a second drying module correspondingly tapped, so that they then can be assembled.

According to another embodiment, it is possible to use attached tubes, running along several drying modules, as shown in figure 4. These tubes may, for example, open at each of their ends into a header 39. The link between a header 39 and a tube 36 is preferably made without a fixed joint. The tube may thus expand and move relative to the header. It is also possible to fasten a tube to a header 39a at one of its ends and leave the tube to slide relative to another header 39b at its other end.

Preferably, the tube is screwed on, on the hot gas admission side. As shown, hot gases may be injected to a central header 39 and recovered from one or more other headers close to the ends of the tunnel.

Owing to the temperature variations, the length of the tunnel may vary substantially. According to one particular embodiment of the oven, the drying modules are thus not all secured to the floor, in order to allow the tunnel to expand in the length direction. For example, the feet 37 may slide along two rails 38 running along the length of the tunnel. One of the drying modules may be fastened to the floor and the other modules left free to move in the length direction. These rails thus contribute to better relative alignment of the modules.

As shown in figure 9, each drying module may also have thermal insulation panels 40 attached to the support structure. These panels may have a metal part 41 and an insulation lining 42. It is possible to use, for example, polyurethane to produce the insulation lining. These panels 40 may be attached laterally and/or on the upper part of the drying module. To compensate for the differences in expansion between the drying modules and these thermal insulation panels 40, it is possible to produce rails 43 in the drying modules, in the length direction of the tunnel. It is possible to produce runners 44, complementary to these rails 43, in the insulation panels 40 so as to allow the runners to slide along the rails of the drying modules.

Insulating panels may also be placed in a gutter integral with the support structure 34. These panels may then be held vertically so as to bear on the support structure by a sliding bolt system between two panels.

According to another embodiment, the number of rollers 32 in the drying modules may be reduced. Thus, the spacing of the rollers 32 in the drying modules close to the outlet of the tunnel may be greater than the spacing of the rollers in the drying modules at the inlet of the tunnel. This is because, when a plasterboard 27

R:\Brevets\18000\18034PCGB doc - 4 septembre 2003 - 11/15 passes along the tunnel, it hardens on approaching the outlet and then has a greater stiffness. The rollers 32 in the drying modules close to the end of the tunnel may thus be spaced apart without any risk of damaging the plasterboards 27.

It is also possible to drive the rollers 32 very simply. Thus, a single motor may be used to drive all the rollers 32. For example, each stage of a drying module may be provided with a chain that drives these rollers. All the rollers of the stage are thus rotated simultaneously. Furthermore, it is possible to use a chain coupled to an additional gear placed at each stage of a module. Thus, by driving one roller of a ; drying module it is possible to rotate all the other rollers of the module. Two consecutive drying modules can then be coupled by coupling, with a single chain, specific gears for each module. Thus, it is found that all the rollers may be coupled and thus driven by a single motor.

It 1s also possible to place a drying module with undriven rollers at the outlet of the tunnel so as to make it easier for an operator to handle the plasterboards.

It is also possible to extend the length of the drying station by connecting additional drying modules. All that is then required is to increase the speed of the : drying drive motor in proportion to the increase in length of the drying station in order to obtain an identical drying time. A drive motor controlled by a variable-speed drive allows the drive speed of the rollers to be easily modified. It is thus possible for the production flow in the drying station to be easily increased while maintaining the same drying time. It is sufficient subsequently to transport to the manufacturing unit one or more containers containing drying modules, and then to connect them to the other modules in order to extend the drying station.

The examples of dimensions given for the manufacturing unit of figure 1 make it possible to transport the hydration modules, the sawing modules and the drying modules in ten containers. One motor may be sufficient to drive the wet plasterboard in the hydration station. One motor may also be sufficient for driving the plasterboard in the tunnel formed by the drying modules. Two motors may be sufficient to ensure hot gas flow through the tunnel.

The above embodiments and examples must be regarded as having been presented by way of illustration but implying no restriction, and the invention is not considered to be limited to the details provided here, rather it may be modified while remaining within the scope of the appended claims.

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Claims

1. A plasterboard manufacturing unit, comprising: - a hydration station, including hydration modules that connect together, - a drying oven, including drying modules that connect together, it being possible for said hydration and drying modules to be able to be inserted into standard transport containers.

2. The manufacturing unit of claim 1, characterized in that the hydration modules have fitting support plates suitable for joining two hydration modules together.

3. The manufacturing unit of claim 1 or 2, characterized in that the hydration station includes a single drive motor.

4. The manufacturing unit of one of the preceding claims, characterized in that the drying modules connect together to form a tunnel through which plasterboards pass.

5. The manufacturing unit of claim 4, characterized in that it furthermore includes a distribution table that places the plasterboards in alignment with various stages of the oven.

6. The manufacturing unit of claim 4 or 5, characterized in that the drying modules are mounted to so as to slide along rails.

7. The manufacturing unit of one of claims 4 to 6, characterized in that thermal insulation panels are attached laterally and above said drying modules.

8. The manufacturing unit of one of claims 4 to 7, characterized in that the drying oven furthermore includes: - a hot gas source; - an indirect heating circuit passing through the tunnel and connected to said hot gas source; and - a direct heating circuit.

9. The manufacturing unit of claim 8, characterized in that it furthermore includes: AMENDED SHEET

- a particle filter connected to the outlet of said indirect heating circuit, the direct heating circuit being connected to the outlet of this particle filter.

10. The manufacturing unit of claim 8 or 9, characterized in that it furthermore includes a device for recycling the gases coming from the direct heating circuit.

11. The manufacturing unit of one of claims 4 to 10, characterized in that it furthermore includes means for driving the plasterboards through the tunnel.

12. The manufacturing unit of claim 11, characterized in that the plasterboard drive means comprise rollers.

13. The manufacturing unit of claim 12, characterized in that the rollers are driven by a single motor.

14. The manufacturing unit of one of claims 8 to 13, characterized in that the gases from the hot gas source are introduced at a temperature of between 180 and 350 degrees into the indirect heating circuit.

15. The manufacturing unit of one of claims 8 to 14, characterized in that the gases are introduced at a temperature of between 120 and 160 degrees into the direct heating circuit.

16. The manufacturing unit of claim 12, characterized in that the spacing of the rollers at the outlet of the tunnel is greater than the spacing of the rollers at the inlet of the tunnel.

17. The manufacturing unit of one of claims 8 to 16, characterized in that the indirect heating circuit has a plurality of tubes, one end of which communicates with and is fastened to a first header and the other end of which communicates and slides with a second header.

18. A method of mounting a manufacturing unit as claimed in one of the preceding claims, comprising steps consisting in: - connecting hydration modules together to form a hydration station; - connecting drying modules together to form a drying oven. AMENDED SHEET

19. A method of converting and increasing the capacity of a manufacturing unit as claimed in one of claims 1 to 17, comprising steps consisting in: - connecting additional hydration modules to the hydration station; - connecting additional drying modules to the drying oven; and - increasing the drive speed of the hydration station and of the drying oven.

20. A plasterboard manufacturing unit substantially as described with reference to Figures 1 to 4 alone or in combination with Figures 5 to 6 and/or Figures 7 to 8 and/or Figure 9. AMENDED SHEET