HEAT-WELDED OR ADHESIVE-BONDED UNITARY CONSTRUCTION CARTRIDGE FOR THE PRODUCTION OF ULTRAPURE WATER

Abstract: Heat-welded or adhesive-bonded unitary construction cartridge for the production of ultrapure water. The invention concerns a device and an assembly method for the production of ultrapure water. The device is constituted of tubes (1) containing the water treatment elements joined by two end plates (2 and 3) by adhesive-bonding or heat-welding. Grids (6) disposed between the tubes (1) and the end plates (2 and 3) retain the resin or carbon balls. Connector terminations (5) provide a hydraulic connection to a control unit. Lateral grooves or projections (19) are used to fix the cartridge by means of quick-release fasteners. The filter (11 + 12 + 16 + 17) is mounted in the tube (1) by means of an adapter (11) which also provides a seal between the inlet and outlet sides of the filter. Holes are provided in the connector terminations (5) and the partitions (7) of the end plates to enable selection of the path of fluid in the water treatment elements. The device in accordance with the invention is intended for use in chemical and microbiological analysis laboratories and in research institutions.

Description: The present invention concerns a device and an assembly method in the form of a heat-welded or adhesive-bonded unitary construction cartridge for the production of ultrapure water. Ultrapure water, having a resistivity greater than 18 MΩ · cm* and a TOC** level less than 20 ppb***, is obtained from weakly ionised water by four or five successive treatments: filtration, activated carbon, mixed anionic and cationic resins, optionally a resin/activated carbon mixture and, finally, microfiltration. These water treatment elements are conventionally assembled separately in the form of cartridges (very low pressure tubes with connectors) incorporated into casings that are often difficult to demount in spite of the need for frequent replacement of the cartridges. Also, the internal volume excluding the treatment elements (for example, the volume between the cartridge and the casing) is high and necessitates a relatively long recirculation time before water of the required quality is obtained. * MΩ · cm = Megohms · cm) ** TOC = Total Organic Compound) *** ppb = parts per billion = 10⁻⁹ The inventive solution consists in assembling tubes (capable of withstanding the working pressure) containing the various elements used to treat the water by means of two end plates of identical shape. The assembly is heat-welded or adhesive-bonded depending on the nature of the plastics materials used. The balls of resins or carbon are retained by a thin grid disposed between the tube and the end plate. The filter is fixed into the tube by means of an adapter which guides it and provides a seal between the inlet and outlet sides of the filter. Forming appropriate holes in the partitions separating the recesses provided in the end plates for the tubes and connectors make it possible to select how the fluid flows in the tubes according to the water treatment elements or their connection in series or in parallel according to the application. The cartridge obtained in this way is connected to a control unit containing a pump, valves and monitor and measurement circuits by means of four connectors, two serving as guides and the other two, provided with holes and fitted with O-ring seals, providing the hydraulic connections between the cartridge and the control unit, the cartridge being fitted to the latter unit by means of a quick-release fastener system. The appended drawings show the invention in the case of a unit with four tubes. Figure 1 shows one example of fluid passing into the cartridge. Figure 2 shows the various component parts of the cartridge in accordance with the invention. Figure 3 shows the end plate as seen from the tube side. Figure 4 shows a cross-section on the line AA. Figure 5 shows a cross-section on the line BB. The cartridge shown in figure 2 comprises the following components: TUBES (1): Four tubes the length and diameter of which correspond to the required capacity and flowrate are cut into lengths. Their thickness depends on the required working pressure. END PLATES (2-3): Two moulded end plates are used to assemble the four tubes (1). The connectors (5) which are provided with holes and fitted with O-ring seals (18) provide an inlet for water to be treated and an outlet for treated water towards the control unit. The other two connectors (4), which are not provided with holes, are used as guides during fitting of the cartridge to the control unit. The provision of appropriate holes in partitions (7) separating the recesses (8) provided for mounting the tubes (1) makes it possible for the fluid to flow in the tubes (see figure 1, for example), with the tubes arranged in series or in parallel, according to the required application. The lip (10) and the star-shaped part (9) support a thin grid (6) in which the pores have a diameter of a few tens of microns. This grid is used only for the recesses corresponding to the tubes filled with resin or carbon balls. A lateral notch or projection (19) is provided on the end plates, as shown in figure 3, for securing the cartridge to the control unit by means of snap fastener locking means or any other quick-release fastening system. ASSEMBLY PART (11) FOR THE FILTER (11 + 12 + 16 + 17): the fluid from the lower end plate (3) passes from the outside to the inside of the filter element (17). It is collected in the "grid-tube" (16) which supports the filter element (17) and is then taken off through the adapter (11) towards the upper end plate (2) and the next treatment element. A plug (12) adhesive-bonded or heat-welded to the filter element (17) and the "grid-tube" (16) closes off the lower end of the filter. Its diameter is less than the inside diameter of the tube (1) to enable the fluid to flow along the filter element. The adapter (11) has a similar shape. A hole (13) at the centre serves to collect the filtered fluid. A flange (14) the diameter of which is slightly less than the outside diameter of the tube (1) with a rim (15) the outside diameter of which is slightly less than the inside diameter of the tube (1) are used to guide and mount the filter (11 + 12 + 16 + 17) in the tube (1). ASSEMBLING THE UNITARY CONSTRUCTION CARTRIDGE: the end plates (2 and 3) are first provided with holes as appropriate to the required result (see above). The grids (6) are adhesive-bonded or heat-welded into the reserved recesses (8). The four tubes (1) are held vertically. The lower end plate (3) is is offered up to the tubes from above. The four tubes are then simultaneously adhesive-bonded or welded to the end plate (3). The assembly is turned over. The tubes (1) are respectively filled with resin and carbon. The filter (11 + 12 + 16 + 17) is inserted into the corresponding tube. The top end plate (2) is offered up and then adhesive-bonded or welded to the tubes. The adapter (11) for the filter (11 + 12 + 16 + 17) is fixed simultaneously to the tube (1) and to the end plate (2 or 3) during this operation. The O-ring seals (18) are mounted on the connectors (5). The fluid-tightness of the completed cartridge is tested using compressed air. In this way there is obtained in accordance with the invention a disposable unitary construction cartridge which can be used in particular for pre-treatment of water feeding apparatus for purifying water by reverse osmosis or demineralisation. In this case the successive treatments supplied to the water are: reduction of the limescale effect by passing the water over a solid polyphosphate type bed, separating out certain colloids and organic substances by passing the water over an anti-colloid resin bed, separating out chlorine and absorbing certain organic substances by passing the water over an activated carbon bed, separating out particles by passing the water through a microporous filter. All or some of these water pre-treatment elements may be used according to the nature of the water to be treated and the application.

Claims: 1. Disposable unitary construction cartridge for the production of ultrapure water comprising a plurality of tubes (1) containing the various elements used to treat the water and connected to two end plates (2 and 3) of identical shape characterized in that said plurality of tubes (1) containing the various elements used to treat the water are assembled by heat-welding or adhesive-bonding to the two end plate (2 and 3) of identical shape, each of said two end plates being provided with recesses (a) delimited by partitions (7) for receiving said plurality of tubes (1) and with two connectors (4 or 5) for the inlet or outlet of the water, the said partitions (7) and connectors (5) having been suitably perforated with holes so as to select how the water to be treated will enter the cartridge, flow into the tubes and leave the cartridge. 2. Disposable cartridge according to claim 1, characterized in that each recess (a) comprises a lip (10) and a star-shaped part (9) for receiving the corresponding tubes (1). 3. Disposable cartridge according to claim 1 or 2 characterized in that said plurality of tubes (1) is four with the same number of recesses provided in both end plates (2 and 3), so as to provide, at will, by a suitable perforation of partitions (7), an hydraulic connection between tubes in series or in parallel. 4. Disposable cartridge according to claim 1 or 2 characterized in that one of said tubes (1) contains a filter element (17) collected in a grid-tube (16) provided with a plug (12) and a centrally perforated adapter (11) said plug (12) having a diameter less than the inside diameter of the tube (1) to enable the water to enter along the filter element from the outside to the inside and to exit through the hole (13) of the adapter (11). 5. Disposable cartridge according to claim 2 characterized in that a thin grid (6) with a pore diameter of a few tens of microns is disposed between a tube (1) and the end plate (2 or 3), this grid being supported by a lip (10) and the star-shape part (9) of the end plates and serving to retain the resin or carbon balls contained in the tube with a very low head loss. 6. Disposable cartridge according to any one of the preceding claims characterized in that two projections or notches (19) on the end plates serve to fix it when it is inserted into a control unit by means of snap fastener locking means or other quick-release fastening means. 7. Disposable cartridge according to claim 1 characterized in that an adapter (11) in one piece with the filter or microfilter element (17) is disposed between the tube (1) and the end plate (2 or 3) to guide the filter (11 + 12 + 16 + 17) in the tube (1), to fix the filter into the cartridge and to provide a seal between the inlet and outlet sides of the filter. 8. Disposable cartridge according to any one of the preceding claims characterized in that the fluid flows in the tubes (1) according to the water treatment elements that they contain by virtue of their connection in series or in parallel, as a result of providing holes in the partitions (7) of the end plates (2 and 3). 9. Method of assembling a device according to any one of claims 1 to 8, characterized in that a single heat-welding or adhesive-bonding operation assembles tubes (1) each containing one or more elements used for water treatment, and in particular a filter (11 + 12 + 16 + 17), onto two end plates (2 and 3) serving as fluid collectors.

Inventors: GAIGNET, YVES
Applicants: MILLIPORE S.A.
Application year: 1988
Main classification: C02F9
IPC codes: C02F9, B01D35, B01D65, C02F1, B01D61