MXPA98005048A - Food settlement for a treatment container - Google Patents

Abstract

The present invention relates to a supply arrangement for a container for the treatment of inhomogeneous fluids comprising a pump casing for receiving the fluid from a fluid supply and for supplying or supplying the fluid to an inlet side of the fluid container. treatment through a pumping means, wherein the fluid transfer port extends between the pump drawer and the treatment vessel for a two-way fluid communication between them, in order to balance or equalize the respective hydrostatic pressures in the treatment container and in the pump drawer

Description

POWER SUPPLY FOR A TREATMENT CONTAINER FIELD OF THE INVENTION The present invention relates to a method and apparatus for feeding and removing, from a fluid treatment apparatus, fluids having several or multiphase phases. It is particularly useful, although not exclusively, in methods to feed and remove dual-phase liquids, such as pulps or suspensions, to and from a flotation apparatus, such as Jameson cells.

BACKGROUND OF THE INVENTION When inhomogeneous fluids are fed to a treatment apparatus, for example when pulps or suspensions are fed to settlers, mixers, flotation apparatus, etc., the treatment apparatus is usually preceded by a pump container or drawer. in which the fluid is fed. Most containers for fluid treatment work best when they have a constant speed or feed rate. The dynamics of fluids and the efficiency of the separation of the flotation cells, in particular, can be altered even by small variations in the feeding regime, therefore, generally to this drawer Pump P2423 / 98MX is connected to a fixed speed pump to maintain a consistent flow or flow rate for the fluid treatment apparatus. However, with this system there are several difficulties. It is vital that the fluid level in the pump drawer does not exceed certain minimum or maximum levels. Since the flow rate provided by the fixed speed pump is constant, the level in the pump drawer will rise and fall or fall in accordance with the rate of supply to the pump drawer. If the feed rate is greater than the fixed speed pump flow rate, the pump drawer will overfill and part of the feed may be lost or short circuit with the treatment vessel. Likewise, if the flow supply is below the fixed speed pump, the level in the pump drawer will fall. If the level of the pump drawer is too low or the pump drawer is empty, the fixed speed pump may be damaged. Some of these difficulties can be overcome by partial recirculation mechanisms. However, this requires additional pumping equipment which also implies an additional associated cost. Alternatively, this can be achieved by the use of a queue recirculation chamber connected to the P2423 / 98MX pump drawer. Another disadvantage of conventional systems is the expense associated with the separate construction. Take for example a flotation cell, as defined in Australian patent application No. 45592/96 (hereinafter referred to as the "Jameson cell".) To separate particulate matter from a pulp or suspension as shown in Figure 1, the cells 100 are placed above the drawer 200 of the pump and the pump 300 transfers the pulp from the drawer 200 of the pump on the ground upwards towards the bank of Jameson cells, the tails then falling down due to the force of gravity, instead of forming a separate recirculation pumping circuit, to again partially recirculate to the pump casing, however, locating the bank of Jameson cells above the pump caisson is expensive in terms of capital of construction costs as well as operating costs, since pump 300 must force the pulp up between 5 and 10 meters to reach the Jameson cells, in an effort to overcome at least some of the disadvantages of the prior art or provide an alternative to the prior art, it is proposed to provide a method and apparatus for providing and removing inhomogeneous fluids towards a container of P2423 / 98MX treatment that is more economical to build and provides a more economical and consistent operation than conventional methods.

SUMMARY OF THE INVENTION In accordance with a first aspect, the present invention provides a feeding arrangement for a container for. the treatment of inhomogeneous fluids comprising a pump box for receiving the fluid from the fluid supply and for supplying or supplying the fluid to an inlet side of the treatment vessel through a pumping means, wherein a port of Fluid transfer extends between the pump casing and the treatment vessel for two-way fluid communication between them, in order to balance the respective hydrostatic pressures in the treatment vessel and in the pump casing. In another aspect, the present invention provides a treatment vessel for the treatment of inhomogeneous fluids, the vessel being divided into a treatment chamber, a pump chamber and one or more exit chambers for one or more components of the fluid not homogeneous and a pumping medium that transfers fluid from the pump chamber to the treatment chamber, where the transfer port is P2423 / 98MX extends between an outlet side of the treatment vessel to the pump chamber to allow fluid two-way communication between, in order to balance the respective hydrostatic pressures in the treatment vessel and in the pump housing. In a first embodiment, the pump drawer and the treatment vessel are side by side. By placing the pump chamber drawer next to the treatment vessel, there is a substantial saving both in the capital of construction costs and also in operating costs, since it is now unnecessary for the pump that transfers the fluid from the pump chamber towards the treatment chamber overcomes the important liquid head in the conventional device (see Figure 1). In another preferred embodiment, the transfer port comprises a recirculation chamber. The fluid leaving the treatment vessel enters the recirculation chamber. One or more control means such as valves, then allow this fluid to flow out of the recirculation chamber and into the outlets. The recirculation chamber is separated from the pump chamber preferably by means of a wall. The recirculation means comprises a hole through the wall that separates the recirculation chamber from the chamber of the P2423 / 98MX pump. Preferably, this hole comprises one or more slits that extend along the floor of the recirculation chambers and the pump. This orifice allows this fluid to flow in both directions. The arrangement provides for the pump chamber to be in fluid communication with the treatment chamber through the recirculation chamber. In this way, the fluid levels between the treatment chamber and the pump chamber can be balanced by the flow through the orifice. In a particularly preferred embodiment, the recirculation means is arranged to agitate the fluid entering the pump chamber through the transfer port. In this way, the fluid is mixed thoroughly before being pumped from the pump chamber into the treatment chamber or container. In a particularly preferred embodiment, the treatment chamber comprises one or more Jameson cells. In another embodiment, the transfer port is configured to supply the fluid to the pump casing which is essentially representative of the content of the total fluid in the recirculation chamber. To explain it, as will be appreciated by persons skilled in the art, when dealing with solid / liquid fluids or solid / gas fluids, if the fluid P2423 / 98MX does not mix continuously, solid particles tend to settle. If someone removes or recirculates some of the fluid in an upper portion of the container, for example, by spilling or overflowing, the fluid has little or no solids content. It is important to recirculate the fluid back to the pump drawer that is representative of the fluid entering the recirculation chamber. For this reason, it is preferred that any orifice between the recirculation chamber and the pump cage be located at a maximum height such that the fluid entering the pump caisson is substantially representative of the general fluid content in the recirculation chamber. . In another embodiment, the port and / or the transfer port may be located in the lowermost portion of the pump casing. This ensures that a significant portion of the solids as well as the liquid are recirculated back to the pump casing. In a further aspect, the present invention provides a method for feeding a fluid to a treatment vessel which comprises feeding a fluid to a pump housing upstream of the treatment vessel, pumping fluid from the pump housing to the vessel of the pump. treatment and provide a transfer port between the pump drawer and the container or treatment to balance their respective pressures P2423 / 98MX hydrostatic. In a further aspect, the present invention provides a method for controlling the head of the fluid in the pump casing and / or a treatment vessel in which the fluid is transferred from the pump casing to the treatment vessel by a pump, the method comprises providing a transfer port between the pump box and the treatment vessel to maintain the two-day fluid communication direct between the treatment vessel and the pump box to balance their respective hydrostatic pressures. It is preferred that the hydrostatic head in the treatment vessel and in the recirculation chamber be larger than in the pump housing. This provides the continuous recirculation of the fluid from the recirculation chamber to the pump drawer. This continuous partial recirculation of fluids can be obtained appropriately sized to the treatment chamber, to the recirculation chamber, to the pump chamber and to the transfer port. Unless the concept clearly requires otherwise, throughout the description and in the claims, the words "comprise" "comprising" and the like shall be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, in the sense of P2423 / 98MX "which includes but not exclusively". Inhomogeneous fluids may include, but are not limited to, pulps.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a cell flotation plant. Conventional jameson, Figure 2 is an external perspective view of an apparatus in accordance with a first embodiment of the present invention, Figure 3 is a perspective view of the interior of the apparatus of Figure 1, Figures 4 and 5 are views in perspective and inside of an apparatus in accordance with a second embodiment of the present invention, Figures 6 and 7 are perspective and internal views of an apparatus in accordance with a third embodiment of the present invention, and Figures 8 and 9 are perspective and plan views of an apparatus in accordance with a fourth embodiment of the present invention, Figure 10 is a perspective view of a P2423 / 98MX apparatus in accordance with a fifth embodiment of the present invention.

FORMS FOR CARRYING OUT THE INVENTION Referring in the first place to Figures 2 and 3, the present invention comprises a structure 10 housing a drawer or pump chamber 20, an exit chamber 40 and a treatment chamber or container 60. Each of these chambers, 20, 40 and the container 60, are in fluid communication between them. The pump box chamber 20 comprises the feed inlet 21 and the outlet 22 to the pump. The pump is not shown in the drawings but will be discussed later. As shown more clearly in Figure 3, the outlet chamber 40 comprises the outlet 41. The output flow rate is controlled by valves 42 as will be discussed below. A transfer port comprising the recirculation chamber 55 extends from the treatment vessel 60 to the pump casing 20. In this recirculation chamber 55 it is in fluid communication with the pump casing 20 through the orifice 70. This orifice can be of any particular shape but, for reasons to be discussed below, a slit at the innermost edge of the pump is preferred. the wall 45 that divides the pump box 20 from the recirculation chamber 55.

P2423 / 98MX As discussed above, the treatment vessel 60 may be of any desired construction. For reasons of illustration in the following description, the treatment vessel 60 is a flotation cell, however, it could also be a settler, a mixer, etc. The apparatus of the invention operates as follows. A pulp or suspension comprising a liquid and particulate material is fed into the pump casing 20 via the inlet 21. A pump (not shown) is connected to the outlet 22 located in an inner portion of the pump casing 20. This pump transfers the pulp from the pump box 20 to the treatment vessel 60 via external pipe. Once the treatment or separation is effected in the container 60, the floated valuable material is separated as a foam in the known manner and exits through the outlet 61. The tails or gangue, flows down along the inclined floor 62 of the tank towards the transfer port 50 and towards the chamber of recirculation 55. If the valves 42 are open, once the recirculation chamber 55 is full, the tails / gangue will flow up through the valves 42 and will exit through the outlet 41. The valves may be example, dart valves. As will be clear for "experienced people P2423 / 98MX in the art, the pump box 20 remains in fluid communication with the treatment vessel 60 via the transfer port 50, the recirculation chamber 55 and the hole 70. This in turn will ensure that the level in the drawer 20 of the pump remains almost constant since the relative heads of liquid in the pump box 20 and in the treatment vessel 60 will then be the amount of recirculated tails returned to the pump box 20, through the transfer port 50 and the orifice 70. In the embodiments shown, the orifice 70 is adjacent to the innermost portion of the pump box. However, as will be explained later, the transfer port 50 and the orifice 70 are configured to supply liquid to the pump drawer which is representative of the fluid content of the recirculation chamber 55. To explain this, there are several modes of operation of the present application. In a first mode of operation or constant flow operation mode, the feed rate through the inlet 21 must be equal to the flow rate of the fixed speed pump that transfers the pulp from the pump box 20 to the treatment vessel. 60. In this case, the level in the drawer 20 of the pump will remain constant as the flow will remain towards the tip float cells. This is P2423 / 98MX an ideal situation that in practice only happens on rare occasions. However, if the feed rate through the inlet 21 is less than the capacity of the fixed speed pump, the level in the pump box 20 will fall below the level of the liquid in the treatment vessel 60. Then the The arrangement of the invention operates in the recirculation mode. In this case, due to the larger liquid head in the treatment vessel 60, the tail / gangue will flow through the transfer port 50 and the recirculation chamber 55 and a portion will be recirculated through the orifice 70 back toward the pump casing 20 until the fluid levels in the treatment vessel 60 and in the pump casing 20 are balanced. This ensures that the fluid level in the pump casing 20 will not fall below the liquid level in the treatment vessel, thus ensuring the constant flow to the treatment vessel which, as discussed above, is particularly important for flotation operations or for similar separation operations. The third mode of operation or spill or overflow mode of operation is that in which the rate of incoming power 21 is greater than the capacity of the fixed speed pump. In this case, -the level in the P2423 / 98MX pump casing 20 will slowly rise until it is above the liquid level in the treatment vessel. Because the liquid head in the pump box 20 is larger than the head of the liquid in the treatment vessel 60, part of the incoming pulp will be forced through the hole 70 from the pump box 20 into the recirculation chamber. until the fluid level in the pump box 20 equals the level in the treatment vessel 60. Even if part of the valuable particulate material enters the recirculation chamber 55, this material will not be lost. Once the feed rate falls below the capacity of the fixed speed pump, the apparatus will revert to its "recirculation" mode of operation the fluid level in the treatment vessel 60 is greater than in the drawer 20 of pump and the fluid will be forced from the recirculation chamber 55 through the orifice 70 back to the pump box 20 from where it will be transferred to the treatment apparatus 60. In accordance with the above, any particulate material that remains in the recirculation chamber 55 will be transferred back to the pump casing 20, from where it will be sent to the treatment vessel 60. This will ensure that none of the pulp "forms a short circuit" to the treatment and exhaust vessel through the outlet 41 P2423 / 98MX The wall 45 that separates the pump box 20 from the outlet chamber 40 preferably has a spillway 46 in its uppermost portion. This spillway 46 is fixed at a distance slightly below the upper point of the container of treatment 60 in such a way that if the level in the pump box 20 continues to rise due to an increase in the feed rate, part of the pulp will pour into the outlet chamber 40 and escape through the outlet 41. This is The only case where part of the input pulp will form a short circuit towards the treatment apparatus. In accordance with the above, it can be seen that the apparatus of the invention can be dimensioned in such a way that the pump box 20 is essentially self-regulating. The fluid communication between the pump box 20 and the container 60 via the hole 70, the recirculation chamber 55 and the outlet chamber 40, ensures that the fluid in the pump box is maintained between the appropriate minimum and maximum levels without need for expensive and complicated recirculation components. In the embodiment shown in Figures 2 and 3, the hole 70 is located adjacent to the lowermost portion of the pump casing 20. This ensures that the solids in the pulp that enter the recirculation chamber P2423 / 98 X 55 are recirculated back to the pump casing 20. The orifice may be located at any point of the pump box 20, provided that the fluid entering the pump box from the recirculation chamber is representative of the bulk content of the fluids of the recirculation chamber. In the prior art, the fluid is generally recirculated from the upper portion of the recirculation chamber. Unless the fluid in the recirculation chamber is mixed continuously, this configuration will mainly recirculate liquid and the solids from the pulp will settle to the bottom of the recirculation chamber and will not be returned to the pump casing. Figures 4 and 5 show the apparatus of the invention when used in conjunction with the Jameson cell and its downpipes. As mentioned above, in the prior art these Jameson cells are located directly above the pump casing (see Figure 1) to allow the recirculation of the tails by gravity back to the pump casing. Of course, this requires not only a large pump to transfer the fluid from the pump cage vertically upwards in about 5-10 meters to the Jameson cells but also requires that an important support structure be built for the Jameson cells. With the P2423 / 98MX apparatus of the invention, a much smaller pump can be used to transfer the incoming pulp to the pump casing 20 towards the entrance of the Jameson 110 inlet. Therefore, it will be clear to those skilled in the art that by providing the pump box 20 on the same level as the treatment apparatus 60 and, preferably, on the same level as the outlet chamber 40, there is an important saving in terms of the construction cost. It is not necessary to provide separate support structures for each of the process components and it is also not necessary to provide expensive tubing to transfer the various fluids from the pump housing to the treatment apparatus and to the output apparatus. It is also clear to those skilled in the art that by providing the pump drawer 20 below and at the same level as the treatment apparatus 60, the pump for transferring the fluid from the pump drawer to the treatment apparatus can be much smaller than a conventional device. The operating costs for this pump will also be reduced, estimated at approximately 20%, compared to a conventional arrangement, since the pump does not require overcoming the important liquid head from the pump drawer to the treatment vessel that is by above.

P2423 / 98MX The Applicant has also found that the arrangement of the invention has significant advantages in terms of the quality of the fluid entering the treatment vessel. To explain this, in the circumstances where the liquid head in the treatment vessel is larger than in the pump casing 20, the liquid will be forced through the recirculation chamber 55 and the orifice 70 towards the pump casing 20. The speed of this portion of recirculated tails can be quite high and serves to affect the liquid in the pump casing 20. In this regard, it is preferred that the hole 70 be provided by a slit which extends substantially transversely to the full width of the recirculation chamber 55 and the pump box 20. With this configuration, the fluid traveling from the recirculation chamber 55 to the pump casing 20 serves to sweep any particulate material that rests on the floor of the pump casing 20 for subsequent removal by the pump through the outlet 22 Other configurations of the orifice 70 have also been devised and, in fact, there may be several orifices between the pump box 20 and the recirculation chamber 55. This agitation of the fluid in the pump box 20 is a distinct advantage over the mechanisms of conventional recirculation, which, in some cases, P2423 / 98MX may require an additional agitation apparatus, for example, an impeller. A further embodiment of the apparatus of the invention is shown in Figures 6 and 7. In this embodiment, a section of the floor 25 of the pump box 20 between the outlet 22 and the inlet 21 is inclined. This makes it possible for any particulate material sedimented in this portion of the floor of the pump box 20 to slide down to the outlet 22 and be picked up by the pump and fed to the settling vessel 60. A further advantage of the present application is that It provides a complete package to the end user without the need to build a separate pump drawer. Generally, the construction and installation of fluid treatment vessels is a specialized business. A plant operator will request a treatment vessel, which will be installed by a contractor. The pump drawer is then usually constructed by the owner / operator of the plant and connected to the treatment vessel. This causes certain difficulties such as that the pump drawer is not always adapted to conform to the particular liquid treatment vessels. Generally, a plant owner / operator will have a standard pump drawer that will be used for virtually any container P2423 / 98MX treatment. As mentioned earlier, maintaining a consistent flow to treatment vessels, such as flotation cells, is vital for efficient operation. A poorly constructed pump drawer can cause the treatment vessel to operate or operate at a less than optimum level. This is not due to any inherent problem in the treatment vessel, but rather the pump casing is not designed to maintain the required flow to the treatment vessel. With the apparatus of the invention, there is no need to build a separate pump drawer since it is already included in the apparatus and is specifically designed to match or adapt to the treatment vessel 60. This is a significant advantage over the prior art. . Not only is the cost of capital less, the owner / operator of the plant will not have to delay the operation of the treatment vessel until the pump drawer can be built, since the bemba drawer / treatment vessel comes as a single unit. It will also help the manufacturers of specialized treatment vessels as it can ensure that the pump casing 20 has the correct dimensions to maintain the optimum operation of the treatment vessel 60. An additional embodiment of the apparatus of the P2423 / 98MX invention is shown in Figures 8 and 9. In this embodiment, the treatment vessel is provided as a circular or conical tank 160. The pump box 120, the outlet chamber 140, the control valves 242, the outlet 241 and recirculation chamber 150 are provided on one side of treatment tank 160. Fluid communication between treatment vessel 160 and pump box 120 is via port 170. This modification of the treatment vessel reduces the cost of the material and of the manufacture. The modification allows the use of thinner steel plates and fewer lateral and base structural supports. It also allows an innovative distribution of multiple treatment tanks, as shown in Figure 9. As will be seen in this embodiment, the outlet chamber 140 of a treatment apparatus 100 can be easily connected to the pump housing 120 of a adjacent container and so on through the pipe 200. Of course, it may be possible to place the feed box of an adjacent container at a slightly lower level such that the tails coming from a first outlet chamber 140 are fed by gravity to the pump drawer 120 of the following treatment apparatus. An additional mode of the apparatus of the P2423 / 98MX invention is shown in Figure 10. In a manner similar to Figure 8, the treatment vessel 260 comprises a circular tank with a conical bottom. Again, this modality has the advantage of a reduced cost in the construction material and in the manufacture. The Figure shows an alternative location arrangement of the pump drawer 220, the recirculation chamber 255 and the outlet chamber 240 with respect to the treatment vessel 260. Compared to the embodiment shown in Figure 8, only the chamber of outlet shares a wall 246 with the treatment vessel. The portion of the fluid that did not float in the treatment chamber 260 enters the recirculation chamber. A portion of the fluid in the recirculation chamber recirculates back to the pump casing 220 through the orifice 270 and the remainder exits through the control valves 242 to the outlet 241 via the outlet chamber 240. These configurations also provide a very small footprint or area for the layout or arrangement of the plant compared to conventional structures. It will be clear to those skilled in the art that the present invention may be incorporated in forms other than those shown in the preferred embodiments, without departing from the spirit or scope of the invention as described.

P2423 / 98MX

Claims (28)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A feeding arrangement for a container for the treatment of inhomogeneous fluids comprising a pump drawer for receiving the fluid from a fluid supply and for providing or supplying the fluid to an inlet side of the treatment vessel through a pumping means, wherein the fluid transfer port extends between the drawer of pump and the treatment vessel for a two-way fluid communication between them, in order to balance or equalize the respective hydrostatic pressures in the treatment vessel and in the pump box.
2. 2. A feeding arrangement according to claim 1, wherein the pump drawer and the treatment vessel are positioned side by side.
3. 3. A feeding arrangement according to claim 1, wherein the transfer port extends from an outlet side of the treatment vessel to the pump casing.
4. 4. A feeding arrangement according to either P2423 / 98 X of the preceding claims, wherein the transfer port includes a recirculation chamber for receiving the fluid from the treatment vessel and for partially recirculating it towards the pump casing. A power supply according to any one of the preceding claims, wherein the transfer port is configured to provide or supply the fluid to the pump cage which is substantially representative of the general fluid content of the recirculation chamber. 6. A feeding arrangement according to any of the preceding claims, wherein the transfer port includes a hole between the recirculation chamber and the pump box, the orifice is located at a maximum height such that the fluid entering the The pump drawer is substantially representative of the raw fluid content of the recirculation chamber. A supply arrangement according to any one of the preceding claims, wherein the transfer port opens to the pump casing at a point adjacent to the lowermost portion of the pump casing. 8. A treatment vessel for treating inhomogeneous fluids, the vessel is divided into a P2423 / 9SMX treatment chamber, a pump chamber and one or more exit chambers for one or more inhomogeneous fluid components and a pumping medium that transfers fluid from the pump chamber to the treatment chamber, where the Transfer port extends between one outlet side of the treatment vessel to the pump chamber to allow fluid communication of two routes between them, in order to equalize or balance the respective hydrostatic pressures in the treatment vessel and in the drawer of the bomb. 9. A treatment vessel according to claim 8, wherein the transfer port of the treatment chamber includes a recirculation chamber in constant fluid communication with the pump chamber. 10. A treatment vessel according to claim 8 or 9, wherein the transfer port is configured to provide or deliver the fluid to the pump chamber, the fluid is representative of the general fluid content of the recirculation chamber. A treatment vessel according to claim 80, wherein the transfer port includes a hole between the recirculation chamber and the pump casing, the orifice is located at a maximum height, so that the fluid entering the drawer of the P2423 / 98MX pump is substantially representative of the general fluid content of the recirculation chamber. 12. A treatment vessel according to any of claims 8 to 11, wherein the transfer port opens to the lowermost portion of the pump casing. 13. A treatment vessel according to any of claims 8 to 12, which further includes a means for agitating the fluid in the pump chamber. A treatment vessel according to claim 13, wherein the means for agitating the fluid in the pump chamber is the fluid entering the pump chamber through the transfer port. 15. A treatment vessel according to any of claims 8 to 13, wherein the treatment chamber includes one or more Jameson cells. 16. A treatment vessel according to any of claims 8 to 15, wherein the treatment chamber, the exit chamber and the pump chamber are connected in sequence. 17. A method for feeding a fluid to a treatment vessel, comprising, feeding a fluid to a pump casing upstream of the treatment vessel, pumping the fluid from the vessel's drawer. P2423 / 98MX pump to the treatment vessel and provide a transfer port between the pump casing and the treatment vessel to equalize or balance the respective hydrostatic pressures. 18. A method for controlling the fluid head in a pump drawer and / or in a treatment vessel, in which the fluid is transferred from the pump drawer to the treatment vessel by a pump, the method comprising providing a transfer port between the pump casing and the treatment vessel to maintain direct and fluid two-way communication between the treatment vessel and the pump casing, in order to equalize or balance their respective hydrostatic pressures. 19. A method according to claim 17 or 18, wherein the transfer port includes a recirculation chamber. A method according to any of claims 17 to 19, wherein the treatment chamber, the recirculation chamber, the pump chamber and the transfer port are dimensioned to ensure that the hydrostatic pressure in the treatment vessel is maintained in a level greater than the electrostatic pressure in the pump chamber and, in this way, continuously recirculates the fluid from the chamber of the pump. P2423 / 98MX recirculation to the pump drawer. 21. A multi-vessel arrangement, wherein a transfer port of a first treatment vessel according to any of claims 8 to 16, is in fluid connection with the pump casing of a second treatment vessel in accordance with Any of claims 8 to 16. 22. A multi-vessel arrangement, wherein a transfer port of a first treatment vessel according to any of claims 8 to 16, is in fluid connection with both the pump housing. of the first treatment vessel as with the pump drawer of a second treatment vessel, according to any of claims 8 to 16. 23. An array of multiple vessels, according to claim 21 or 22, wherein the second container is downstream of the first container. 24. A multiple container arrangement, according to any of claims 21 to 23, wherein the fluid is fed from the first container to the second container by gravity. 25. A feeding arrangement substantially P2423 / 98MX as described above with reference to any of the accompanying drawings. 26. A treatment vessel substantially as described above with reference to any of the accompanying drawings. 27. A method for feeding a fluid to a treatment vessel substantially as described with reference to any of the accompanying drawings. 28. A method for controlling the fluid head in a pump drawer and / or in a treatment vessel, substantially as described above with reference to any of the accompanying drawings. P2423 / 98MX