MULTI-PURPOSE APPARATUS

The present invention relates to multi-purpose apparatus and more particularly, though not exclusively to a vessel capable of completing the operations which would normally necessitate the use of three separate units, for example a reaction vessel, an isolator filter and a dryer.

Traditionally, many chemical processes, particularly the production of fine chemicals and pharmaceuticals require a three stage operation which includes the steps of:

1. reacting the starting materials and crystalising the resulting product,

2. filtering the product, and

3. drying it.

This process requires at least two vessels, a reaction vessel and a filtration drying unit. Both the reaction vessel and the filtration drying unit utilize drive shafts to operate agitators and smoothing arms respectively. The drives are both expensive and bulky as are the vessels. Furthermore, the reaction vessel is ideally set up above and to the side of the filtration unit so that the reactant can be easily transferred from the reaction vessel to the filtration drying unit. This arrangement takes up

space (both height and width) which could be utilized in other ways.

Also from the processing stand point the transfer of material at the end of each stage gives rise to a risk of contamination and reduced yields.

An improved vessel has been supplied by Rosenmund AG under the Trade Mark NUTREX. This multi-purpose apparatus offers the capability of carrying out the operations of reaction, filtration and drying in immediate sequence within a single vessel.

One end of the vessel acts as a reaction/crystallization unit whilst the other end acts as a filtration/washing/reslurry unit, it being necessary to rotate the single vessel through 180° from a position in which reaction takes place to a position in which filtration takes place. The apparatus can then be rotated through a further 50° (230° in total) to a position in which drying and discharge can take place.

Whilst such an arrangement saves- space, there being a single unit compared to the at least two separate units of conventional apparatus the arrangement suffers a number of draw backs. These include:

1. a requirement to disconnect and reconnect the service pipes for the different operations as a result

of rotating the apparatus,

2. the provision of two drive systems, a large one for rotating the apparatus and another for controlling a double-shafted agitator system comprising a stationary agitator for reaction and an axially operable smoothing arm for the filtration process, and

3. a space requirement for rotation of the apparatus and the provision of extra safety features as a result of the apparatus\'s rotation

It is an object of the invention to provide an \'improved multi-purpose apparatus without the problems associated with the aforementioned prior art.

According to the present invention there is provided a multi-purpose apparatus comprising first and second units, the first unit serving as a reaction vessel and the second unit serving as a filtration and/or drying unit, means enabling isolation and communication therebetween, the apparatus being characterised in that an elongate drive shaft passes through the reaction vessel into the filtration and/or drying unit or vice-versa, said drive shaft being capable of both longitudinal and rotational movement within the respective first and second units.

By providing an elongate drive shaft through the first unit into the second unit the objects of the invention are met.

Preferably the elongate drive shaft is a single drive shaft, although it may comprise two drive shafts coupled at respective ends to form an elongate drive shaft.

Preferably the first and second units will be the first and second chambers of a single vessel which is sub-divided by the provision of a crosswall passing therebetween. Alternatively, the two units may be separate vessels which are positioned one above the other such that a single elongate drive shaft can be mounted so as to operate within both units.

In one embodiment the multi-purpose apparatus comprises a generally cylindrical vessel having a top portion and a base portion which are connected by a side wall, which vessel is sub-divided by a crosswall into an upper reaction chamber and a lower filtration chamber the crosswall extending inwards of the side wall substantially perpendicular to the longitudinal axis of an elongate drive shaft which passes through the top portion into the reaction chamber and through the crosswall into the filtration chamber.

In another embodiment the cross-wall may be inclined at an angle other than substantially 90° to the side wall to aid communication between the two chambers. In a further embodiment it may be concave

or convex.

Preferably, though not essentially the drive shaft passes through the centre of the top portion of the vessel into the reaction chamber and through the centre of the crosswall into the filtration chamber situated therebelow.

The drive shaft is preferably mounted above the multi-purpose vessel in a manner allowing both longitudinal and rotational movement of the drive shaft to occur. To this end the drive shaft is preferably retained about the cross member by a bellows and rotary bearings which allow for both longitudinal and rotational movement. The bellows also serve to keep the reaction mixture and product formed therefrom away from the bearings.

The single drive can be used to control both agitation during the reaction stage and smoothing and pressing during filtration. To this end the drive shaft has an agitator arm fitted thereto in the reaction chamber and a smoothing and pressing arm fitted thereto at the base of the drive shaft in the filtration chamber.

The vessel is provided with communicating means between the reaction and filtration chambers. In one embodiment the communication means takes the form of a U-tube which exits from the side and bottom of the

reaction chamber and re-enteres the filtration chamber through the side wall about mid-way down the filtration chamber.

This will readily allow the fast transfer of material from one chamber to the other by vacuum, pressure or a combination thereof.

The apparatus also comprises an access port at the top of the reaction vessel and an exit port at the bottom of the fitration chamber as well as valve means for removing the product.

Preferably one or both of the top of the reaction chamber or the base of the filtration unit are releasably attached to the side walls to enable easy access to the internal workings of the vessel.

Preferably the internal face of the side wall of the vessel is provided with spray systems there around so that product can be washed from the reaction vessel into the filtration unit thereby increasing yields and reducing the risk of cross contamination.

The invention will now be described, by way of example only, with reference to the drawing which is a simplified cross sectional view of one such multi¬ purpose apparatus.

The multi-purpose apparatus 10 comprises a generally cylindrical vessel 12 with a top portion 14 and a bottom portion 18 which are connected to one

another by a side wall 16. The vessel 12 is divided into an upper reaction unit 20 and a lower filtration unit 22 by a crosswall 24 which is situated -8- approximately mid way down the vessel. The crosswall

24 lies substantially perpendicular to the plane of side wall 16 and the longitudinal axis 26 of elongate drive shaft 28. The drive shaft 28 is driven by a drive 30 with a lifting/lowering facility which is situated above the vessel 12. From the drive 30 the drive shaft 28 passes through a spacer/support 32 and

\'sealingly through the centre portion 34 of the lid portion 36 of the reaction vessel 20. It then passes from the reaction vessel 20 into the filtration unit

22 through cross wall 24 where it is sealingly engaged therein by bearings 38. These bearings 38 provide support for the drive shaft and allow for both rotational and longitudinal movement thereof. The bearings 38 are housed in a bellows 40 which allow for movement of the shaft in the direction of the shafts longitudinal axis. A valve/pump 42 is provided between the reaction vessel 20 and filtration unit 22 to allow the transfer of the reacted product to the filtration unit 22. In the embodiment illustrated this takes the form of a U-tube 44 which extend from the lower surface 46 of the crosswall 24 through side wall 16 and downwards where it re-enters the

filtration unit 22 approximately mid-way down. Other valve systems such as the one passing through the crosswall 24 could, however, be used.

At the bottom 48 of the filtration chamber there is provided a removeable base 50 with a filter plate 52 fitted thereto. The base 50 and filter plate 52 are releasably attached to the wall 16 of chamber 22 by fastening means 54.

In use reactants are loaded into the reaction chamber 20 through inlet port 56 provided in lid portion 36 of the reaction chamber 20. The reactants are then processed, the drive 30 controlling the drive shaft 28 which in turn operates an agitator arm 58 which is attached thereto.

When the reaction is complete the reaction mix can be transferred from the reaction chamber 20 into the filtration chamber 22 via U-tube 44 and valve/pump 42. The product can be washed through by a spray system which is not shown for simplicity.

Once transferred to the filtration chamber, filtration can be completed by filtering the slurry through filter plate 52, the liquid being drawn off, under pressure or vacuum if necessary, through valve 60 outlet 62. The resulting cake can be washed using a spray system (again not shown for simplicity) and re-suspended by driving agitator arm 64 provided at

the end 66 of drive shaft 28. The wash liquid is then filtered off.

The product can then be dried by the provision of one or more from underplate heating, side wall or agitator heating, and the application of vacuum heating and removed through a valve system. Again this is not shown in the drawing for the purposes of simplicity. The base 50 and filter plate 52 are releasably attached to wall 16 by clamps 54 to allow access to the inside of the chamber 22.