JP2003508194A - Cross-flow filtration method and equipment for performing this method - Google Patents

Abstract

(57) [Summary] Filtration module (5), vessel (1) for medium (2) to be filtered, and feed pump (4) provided between vessel (1) and filtration module (5) In a cross-flow filtration system comprising: (1) the pressure of the medium (2) in the vessel (1) is increased by compressed gas or other devices. As a result, a high-concentration medium (2) can be transported to the feed pump (4), thereby avoiding interruptions in the function of the installation.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to a substance stream containing a portion to be separated by filtration, which is conveyed as a trap through a filtration module provided with a porous diaphragm by a pump, and a container for a fluid medium is a pump. It relates to a cross-flow filtration method for separating a liquid from a fluent medium, which is directly or indirectly connected in the foreground and an installation for carrying out this method.

Such a method is used in equipment for separating a mixture of solid and liquid into a solid component and a liquid component with a porous diaphragm. The liquid component permeates the diaphragm as a penetrant, and the solid component is retained as a trap. When purifying wastewater, the purpose is to produce raw water. This raw water should separate impurities as thoroughly as possible. For juice production, the juice should be separated from the cloudy material of the original fruit juice.

State of the art A method for concentrating a mixture of solids and liquids using equipment equipped with a diaphragm module having a trap circuit is described in EP 0,682,559 (
Known by Bucher-Guyer). In that case, in the first step, the trap supply flow is kept substantially constant in the diaphragm module. When the inlet pressure of the diaphragm module exceeds the set target value based on the concentration of the trapped substance, the target value of the trapped substance concentration is achieved by reducing the trapped substance conveying flow in the second step. Until the inlet pressure is kept constant. The concentrated traps are then discharged from the circuit.

In the case of this known method, when the concentration of the trapped substance is high, fine bubbles reach the trapped substance circulation pump, and the function of the pump is interrupted. For this reason, screw eccentric pumps are used as circulation pumps in the case of concentrators. This shifts the interruption of the pump's function to a trap condition in which the trap is no longer drawn into the pump inlet. When no through filtration is used, this problem limits maximum juice yield, for example in direct filtration of fruit juice.

DISCLOSURE OF THE INVENTION Starting from the above state of the art, the problem underlying the present invention is such that a high concentration of trapped material is supplied to the feed pump, thereby avoiding interruption of the pump. It is to improve the cross-flow filtration method mentioned at the beginning.

The invention has the features of independent claims 1 and 3. Advantageous embodiments and developments have the features of the dependent claims.

A cross-flow filtration method according to the invention of the type mentioned at the outset comprises applying a pressure to the fluid medium in such a way that the fluid medium in the vessel is supplied under pressure to the inlet of the pump. Is approximately in the range between the ambient pressure of the filtration module and the outlet pressure of the pump.

In a particularly advantageous embodiment of the process according to the invention, the medium container is a closed batch tank, in which the medium circulates as a trap in the facility and is returned to the closed batch tank in a batch operation method. And the medium is pressurized by energizing it with compressed gas in the batch tank.

Other embodiments and advantages of the invention will be apparent from the features further recited in the claims and the embodiments described below. The features recited in the claims can be arbitrarily combined with each other if they are not mutually exclusive.

DETAILED DESCRIPTION OF THE INVENTION The invention and its advantageous embodiments and developments will now be described and explained in detail on the basis of the examples shown in the figures. The features that can be perceived from the following description and the drawings are applicable according to the invention either individually or in any combination.

As shown in the schematic cross-sectional view of FIG. 1 of a cross-flow filtration installation according to the invention, this filtration installation comprises a container 1 for a product 2 to be filtered. The product 2 is fed via a pipe 3 and a feed pump 4 to a filtration module 5 as is known per se. The filtration module 5 includes a porous diaphragm (membrane) 6. This diaphragm is used in microfiltration or ultrafiltration according to its separation limit. In the filtration module 5, the product is separated into a permeate as a filtrate and a trapped substance (residue).

A discharge pipe 7 is provided for the permeate, and a discharge pipe 8 is provided for the trapped material. The trapped substance returns to the container 1 containing the product 2 via the pipe 8, the radial pump 9 and the shutoff valve 10. Thereby, as is known, a closed trap circuit is formed. As shown in FIG. 1, in the container 1 there is a free space 11 above the product 2. Compressed gas can be supplied to this free space via a pipe 12 and a control valve 13. Another tube 14 is provided in the container 1 for supplying the product 2. A discharge valve 15 branching from the shutoff valve 10 cooperates with the shutoff valve 10. This discharge valve has a catch discharge pipe 16
Are connected.

Therefore, the installation of FIG. 1 operates in batch mode and the container 1 acts as a batch tank. Since the permeate is separated and discharged through the pipe 7, the product in the container 1 becomes more and more concentrated. At that time, by applying pressure to the free space 11 by the compressed gas, formation of bubbles in the trapped substance in the pipe 3 is avoided, and product introduction to the supply pump 4 and delivery of the supply pump are ensured. Due to the good functioning of the installation, FIG. 1 also schematically shows the control circuit for the gas pressure in the free space 11 and the output power of the pumps 4, 9. The gas pressure in the free space 11 is controlled via the pressure sensors 17 and 18 and the control valve 13. The output of the pumps 4, 9 and thus the operating pressure of the filtration module 5 are controlled via the flow rate sensor 19 and the pressure sensors 20, 21.

FIG. 2 schematically shows another cross-flow type filtration equipment according to the present invention. In this case, the same reference numerals as in FIG. 1 indicate components having corresponding functions. Figure 2
Comprises an open container 1'for the product 2 to be filtered. The product is supplied via the pipe 14 and discharged via the pipe 3. In the first operating method, the product 2 is the supply pump 4
To reach the filtration module 5. From there, the permeate is separated and discharged through the pipe 7, and the trapped substance is discharged through the discharge pipe 8, the control valve 22 and the shutoff valve 10 and opened to the container 1 '.
Returned to. The closed trap circuit itself is known.

The function of the closed container 1 of FIG. 1 for increasing the pressure is taken up in the installation of FIG. 2 by a separate small closed pressure container 1 ″, which is juxtaposed with the open container 1 ′. Connected to the pump 4 for supplying the discharge pipe 8 of the filtration module 5 via the control valve 22
Connected to the entrance. In the second operation method, the product 2 is trapped in the circuit of the pressure vessel 1
A shut-off valve 23 is provided in addition to the shut-off valve 10 in order to circulate through "", whereby the container 1'can be completely separated from the catch circuit.

At the inlet or the outlet of the pressure vessel 1 ″, one other shutoff valve 24 or 25 is inserted, respectively. This shutoff valve, together with the shutoff valves 10 and 23, switches the above operating method. The pressure vessel 1 ″ corresponds to the vessel 1 of FIG. 1 with a control valve 13 ′ for compressed gas above the product 2, which is fed via a pipe 12, and for feeding traps. A supply pump 26 is provided. Further, a washing water supply pipe 28 is disposed between the pressure vessel 1 ″ and the supply pump 4 via a shutoff valve 27. This allows concentration after one filtration is completed during batch operation. Discharged pipe 1
Extruded through 6.

In the case of the equipment of FIG. 2 also, a control circuit is provided. This control circuit controls the delivery output of the pump 4 via the pressure sensors 20 and 21 and the flow rate sensor 19 and the operating pressure in the control valve 22 and thus in the filtration module 5. That is, in the case of the equipment of FIG. 2, the product 2 supplies the pressure generated in the pressure vessel 1 ″ to the inlet of the supply pump 4. This pressure is the same as that of the equipment of FIG. Between ambient pressure and outlet pressure of feed pump 4.

The equipment shown in FIG. 2 is the same as the well-known equipment provided with an open batch tank 1 ′, and the pressure vessel 1
It is advantageous that it can be constructed by retrofitting with a "". In the first mode of operation, this installation operates via an open container 1'until a supply problem of the supply pump 4 occurs due to the concentration of trapped substances. After switching to the second operation method using the small pressure vessel 1 ″, a small amount of batches are successively operated one by one in succession to a high concentration. For that purpose, a low-cost radial pump is sufficient as the supply pump 4.

FIG. 3 schematically shows a closed product container 1 which can be used instead of the container 1 of FIG. This product container 1 also includes a pipe 12 for supplying a compressed gas and a pipe 8 for returning a trapped substance. In order to enable a good supply of strongly concentrated traps 2, the feed pump 4 of FIG. 1 is designed here as an eccentric screw pump 4 ′ and is connected directly to the outlet of the product container 1. The stirring mechanism 30 in the container 1 to which the supply screw 31 is connected further facilitates the supply of the trapped material 2 to the filtration module 5 of FIG. 1.

FIG. 4 shows a modification of the product container 1 of FIG. In this case, the space for the compressed gas supplied from the tube 12 is separated by the press bellows 35 from the space for the product 2 supplied from the tube 14. As indicated by the broken line 35 ', the press bellows 35 are fixed and formed in the product container 1 so that the division of the compressed gas sub-chamber and the product sub-chamber can be varied within wide limits. The rotation direction of the supply pump 4'is
In order to make the screw 36 available for the introduction of the product 2 at the same time, it is the opposite of the structure of FIG.

FIG. 5 shows a modification of the product container 1 of FIG. In this case, the container 1 has a cylindrical shape and is supported so that its axis is horizontal. Press bellows 35 to separate
″ Is correspondingly fixed to the wall of the cylinder along a line which lies in the horizontal plane in which the cylinder axis lies.

FIG. 6 shows a modification of the product container 1 of FIG. In the case of this deformation, screw 3
The feed pump 4'comprising 6 is directly connected to the outlet of the container 1 similar to the embodiment of FIG. In this case, the supply screw 31 and the stirring mechanism 30 of FIG. 3 are omitted.

FIG. 7 schematically shows a variant of the installation of FIG. In the case of this variant, the outlet tube 8 of the diaphragm module 5 is used to supply the trapped material 2 in a circuit with the tube 3.
It is sufficient to provide the radial pump 9 only in the. The pressure increase of the product 2 in the container 1 by the compressed gas from the pipe 12 is sufficient to avoid the feed problem at the inlet of the single feed pump 9.

In the case of the installation of FIG. 1, when the use of compressed gas in the product container 1 for increasing the pressure is stopped, the installation of the product container 1 ″ ″ according to FIG. 8 can be used in this installation. The product container 1 ″ ″ comprises an inserted press piston 40 and means 41 for operating this press piston. In this case, the return tube 8 for the catch is preferably movable and guided through the press piston 40.

Fig. 9 shows a variant of the product container 1 "" of Fig. 8. In this variant the product container is connected with an eccentric screw pump 4 for the product 2. The piston 40 has a good seal. For this purpose, a ring 42 is provided, in the position shown in broken lines the piston 40 has already pushed part of the product 2 towards the filtration module 5 of FIG.
Some of this product does not return entirely via tube 8 because the filtrate is drained from tube 7.

FIG. 10 shows a variant of the product container 1 ″ ″ of FIG. 9 with an expanded introduction for the eccentric screw pump 4 ′, whereby a strongly concentrated product is obtained according to FIG.
It can be introduced at a lower pressure than that of the product container.

FIG. 11 shows a modification of the equipment of FIG. In this variant, the gas pressure vessel 1 ″ for the product 2 has been replaced by a pressure vessel 45 with a press piston 46. The retrofitting of the pressure vessel 45 to the known installation with an open batch tank 1 ′ is: It is possible at a lower cost than retrofitting in FIG.

FIG. 12 shows a product container 1 for the installation of FIG. 2 incorporating a conveying screw 50.
It shows a variation of ′. Such a conveying screw 50 is sufficient to ensure product introduction of the feed pump of FIG. 2 in the subsequent arrangement when processing a product which still has sufficient flowability.

FIG. 13 shows a variant of the product container 1 ′ for the installation of FIG. Similar to the variant of FIG. 3, the variant of FIG. 13 has an incorporated stirring mechanism 30. The eccentric screw pump 4'is a simple conveying screw 5 installed at the outlet of the product container 1 '.
Replaced by 0 '. If the transport screw is simple, this is sufficient.

FIG. 14 shows a variant of the installation of FIG. 1 with an inner product circuit. Container 1
The gas pressure in the free space 11 allows a trouble-free operation of the feed pump, as in the case of the installation of FIG. In this case, the control valve 22 cooperates with the pressure sensor 20 in order to adjust the inlet pressure in the filtration module 5, similar to the variant of FIG. The inner product circuit is formed by the second transfer pump 51 and the trap return pipe 52 from the control valve 22 to the supply pump 51.

During operation, the outer circuit comprises a vessel 1, a tube 3, a filtration module 5, a tube 8 and a shutoff valve 1.
Work is carried out through 0, and the inner circuit works simultaneously through the catch return pipe 52, the feed pump 51, the filtration module 5 and the pipe 8. A relatively large flow rate of, for example, 30 m ³ / hour flows through the catching substance return pipe 52, whereas a relatively low flow rate of product of, for example, 1.5 m ³ / hour flows from the container 1. This flow rate corresponds to the amount of permeate discharged from the pipe 7. When the container 1 is located away from the filtration module 5, a low flow rate of product is allowed to flow over this separation distance and a large amount of trapped material is collected in the relatively short inner circuit via the trap return tube 52. All you have to do is shed.

[Brief description of drawings]

[Figure 1]   1 is a schematic view of a cross flow filtration facility according to the present invention.

[Fig. 2]   FIG. 6 is a schematic view of another cross-flow filtration facility according to the present invention.

3 is a schematic view of the product container of FIG. 1 equipped with a gas pressing device, an eccentric screw pump and a stirring mechanism.

4 shows a variant of the product container of FIG. 3, in which the compressed gas and the product are separated by a press bellows.

5 shows a variant of the product container of FIG. 4, in which the container has the form of a cylinder with a horizontally supported shaft.

[Figure 6]   It is a figure which shows the deformation | transformation of the product container of FIG.

FIG. 7 shows a variant of the installation of FIG. 1 with a catcher circuit in which a product feed pump is arranged at the outlet of the filtration module.

8 is a schematic view of a variation of the product container of FIG. 1 with a press piston inserted to increase product pressure.

9 shows a variation of the product container of FIG. 8 with an eccentric screw pump for the product connected.

FIG. 10 is a view showing a modification of the product container of FIG. 9 in which the retracting portion of the eccentric screw pump is expanded.

FIG. 11 shows a variant of the installation of FIG. 2, in which the product gas pressure vessel is replaced by a pressure vessel with a press piston.

FIG. 12 is a diagram showing a modification of the product container for the equipment of FIG. 2 that incorporates a conveying screw.

[Fig. 13]   FIG. 3 is a diagram showing a modification of the product container for the equipment of FIG. 2 that incorporates a stirring mechanism.

FIG. 14   FIG. 3 shows a variant of the installation of FIG. 1 with an inner product circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 4/00 103 A23L 2/00 K

Claims (15)

[Claims] 1. A material flow comprising a portion to be separated by filtration is pumped (4, 4 ', 9).
, 51) is conveyed as a trap through a filtration module (5) equipped with a porous diaphragm (6) and is a container (1, 1 ″, 1 ″) for a fluid medium (2).
In the cross-flow filtration method for separating a liquid from a fluid medium (2), in which the fluid medium (2) is connected directly or indirectly before the pump, 4 ', 9, 51) so that it is pressurized and supplied to the inlet,
A pressure is applied to the fluid medium (2) in the vessel (1,1 ", 1"", 45), which pressure lies in the range between approximately the ambient pressure of the filtration module (5) and the outlet pressure of the pump. A cross-flow filtration method characterized by being present. 2. A batch tank (1,1 ″) having a closed medium container,
The medium is returned to the batch tank (1,1 ″) that is closed as a trap in the circuit in the equipment by the batch operation method, and the medium (2) is attached as compressed gas in the batch tank (1,1 ″). The method of claim 1, wherein the pressure is applied by urging. 3. At least one filtration module (5) comprising a tangentially overflowable porous diaphragm (6) and a filtration module (5) for collecting media (2) to be filtered as traps. ), Feed pumps (4, 4 ',
9.51) and a container (1,1 ", 1"", 45) for the medium (2) to be filtered, which is arranged directly or indirectly before the feed pump. Item 1
A facility for carrying out the described method, comprising means (12,40,41,46) for increasing the pressure of the medium (2) in the vessel (1,1 ", 1"", 45). Equipment characterized by that. 4. Equipment according to claim 3, characterized in that it comprises at least one filtration module (5) with a diaphragm (6), which diaphragm is used in microfiltration or ultrafiltration according to its separation limits. . 5. The container is a batch tank (1 ″ ″) for the medium (2), and the means for increasing the pressure of the medium include a press piston (40) inserted in the batch tank (1 ″ ″). 5. Equipment according to claim 3 or 4, characterized in that it comprises means for operating the press piston. 6. A batch tank (1,1 ″) for a medium (2), the container of which is closed, wherein the means for increasing the pressure of the medium (2) comprises a pressure for energizing the medium (2). 5. Equipment according to claim 3 or 4, characterized in that it comprises means (12, 13) for supplying the lower gas to the batch tank (1, 1 "). 7. A batch tank (1 ″) provided with two batch tanks (1 ′, 1 ″) in a trap circuit, one batch tank being a closed batch tank, and the other batch tank (1 ′). 7. The installation according to claim 6, which has a smaller volume than 8. The medium (2) to be filtered under pressure and the gas in the closed batch tank (1) are separated by a press bellows (35, 35 ″). The listed equipment. 9. The installation according to claim 8, characterized in that the closed batch tank (1) has the shape of a cylinder and is supported by a horizontal shaft. 10. The container is a pressure container (45) for a medium (2), the medium (2)
) Means for increasing the pressure of the press piston (45) inserted in the pressure vessel (45).
46) Equipment according to claim 3 or 4, characterized in that it comprises a means (46), the press piston being provided with means for operating it. 11. Another batch tank is connected and arranged before the closed batch tank, and the medium can be supplied from this other batch tank to the closed batch tank by a pressure pump. Equipment described in 6. 12. Means for increasing the pressure of the medium (2) comprises an eccentric screw pump (4 ′) integrated at the outlet of the container (1,1 ″ ″) for the medium (2). The facility according to claim 3 or 4, which is characterized. 13. The container (1 ″ ″), in addition to the eccentric screw pump (4 ′), comprises an inserted press piston (40) and its operating means (41). The listed equipment. 14. Equipment according to claim 12, characterized in that the container (1) is provided with a stirring mechanism (30). 15. Means for increasing the pressure of the medium (2) comprises a conveying screw (31, 50) incorporated in the container (1), which conveying screw conveys its contents to the container outlet. The facility according to claim 3 or 4, characterized in that: