US 3883431 A
A cleaning apparatus for use in connection with fluid-flow tubing systems, particularly for cleaning tubular semipermeable membranes, comprising a cartridge which is adapted to supply scrubbing and cleaning objects such as sponge balls into the tubing system, and which is adapted to receive and contain the objects when the direction of fluid flow in the system is reversed. A by-pass conduit and a check valve are provided to permit fluid to flow around the cartridge when the flow direction is reversed.
Claims available in
Description (OCR text may contain errors)
United States Patent Ishii et a1.
CLEANING APPARATUS inventors: Kiyoshi lshii; Shobu Konomi, both of Ohimachi', Yoshio lshiguro, Tokyo, all of Japan Assignee: Daicel Ltd., Osaka, Japan Filed: Apr. 22, 1974 Appl. No.: 462,629
Foreign Application Priority Data Apr 25, 1973 Japan 4849389 US. Cl. 210/134; 15/10406 A; 15/351; 137/268; 210/136; 210/433; 210/23; 210/79 Int. Cl B081) 9/04 Field of Search 137/528, 496, 112, 493, 137/268, 599', 210/23, 231, 353, 136, 134, 130, 433, 79; l5/104.06 A, 3.51
References Cited UNITED STATES PATENTS 4/1920 Doyle 137/493 X [451 May 13,1975
Osborn et a1. .1 137/268 X Zajdler 137/528 X Primary E.raminerMartin P. Schwadron Assistant Examiner-Robert J. Miller Attorney, Agent, or Firm-Woodhams, Blanchard and Flynn  ABSTRACT A cleaning apparatus for use in connection with fluidflow tubing systems, particularly for cleaning tubular semipermeable membranes, comprising a cartridge which is adapted to supply scrubbing and cleaning objects such as sponge balls into the tubing system, and which is adapted to receive and contain the objects when the direction of fluid flow in the system is reversed. A by-pass conduit and a check valve are provided to permit fluid to flow around the cartridge when the flow direction is reversed.
7 Claims, 10 Drawing Figures 1 CLEANING APPARATUS BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to an apparatus for cleaning the inner surfaces of tubular members, particularly tubular semipermeable membranes.
2. Description of the Prior Art Reduction of the permeation efficiency of osmotic membranes by accumulation of slime or deposits on the internal surfaces thereof is generally unavoidable in such processes as filtration, ultrafiltration and reverse osmosis. As a means for effectively restoring the permeation efficiency of the membrane, there has been developed a method in which the membrane inner surface is rubbed and cleaned by a sponge ball or the like. However, it is very inconvenient to insert a rubbing and cleaning member, such as a sponge ball, into the fluidflow system and then withdrawing said member from the system after cleaning the membrane at prescribed intervals of several minutes to several hours, during the continuous operation of such equipment.
As a means of overcoming this problem, we previously proposed an automatic washing apparatus in which at least two mesh screens are mounted in fluidflow system and sponge balls are inserted between said mesh screens so that said balls are automatically and intermittently moved back and forth through the system in response to the switching action of valves disposed in the tubing system, whereby the inside of the tubing system is cleaned (U.S. Pat. application Ser. No. 282 449 now U.S. Pat. No. 3,819,5I3). Because the movement of the rubbing and cleaning member or members is performed by utilizing only the dynamic pressure of the liquid flowing through the system, accurate operation is not always achieved.
SUMMARY OF THE INVENTION This invention relates to an improvement in our earlier apparatus, and a primary object of this invention is to provide a washing apparatus having a structure such that the movement of the rubbing and cleaning members can be performed more positively.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectional view of the cartridge employed in the apparatus of the present invention.
FIG. 2 is a perspective view of the check valve used in the cartridge of FIG. 1.
FIG. 3 is a schematic illustration of the overall fluidflow system.
FIGS. 4A through 4D are diagrammatic plane views showing the shapes of several porous barriers.
FIGS. 5A through 5C are perspective views showing the shapes of several check valves.
This invention relates to an apparatus for rubbing and cleaning tubing systems such as the inner face or surface of a tubular osmotic semipermeable membrane in a liquid treatment system or the like utilizing reverse osmotic pressure, in which one or more rubbing and cleaning members are moved reciprocatively, i.e., back and forth, in the tubing system in order to clean same.
Referring to FIG. 1, the invention provides a casing 4 serving as a cartridge or container for receiving the rubbing and cleaning members 1. The casing 4 is open at its rightward end and is adapted for connection to the tubing system 12 so that the members 1 can move from the casing through the tubing system and vice versa. At its leftward end the casing 4 has a fixed porous barrier 7 which permits passage of fluid but does not allow passage of the rubbing and cleaning members 1. The casing 4 is disposed within a housing 8 and is spaced therefrom to define an annular by-pass passage 6 surrounding the casing 4. The by-pass passage 6 extends from the vicinity of the rightward end of the casing 4 to a postition beyond the barrier 7. A tube 20 extends axially from barrier 7 into the fitting 21 attached to the leftward end of the housing 8. The tube 20 has openings 5 so that fluid can flow from the fitting 21 into the by-pass passage 6, and vice versa. A check valve 3 is slidably movable within the tube 20 and is adapted to open and close the opening 5 in said tube 20. The check valve 3 is automatically opened and closed by reversals of the direction of flow through the housing 8, as described below.
One or more spherical elastically compressible members, preferably sponge balls, are used as the rubbing and cleaning members 1 in the apparatus of the present invention. The rightward end of the housing 8 has an opening 9 adapted to be connected, as by a threaded or soldered connection, to the tubing system, which preferably is a reverse osmotic semipermeable membrane module 12 as shown in FIG. 3. By the provision of such structure, connection of the reverse osmotic semipermeable membrane module 12 (tubing system) to the housing 8 can be accomplished very easily. The opening 9 is sized so that the balls 1 can move therethrough from the casing 4 into the membrane module 12 and vice versa. The fitting 21 on the opposite end of the housing 8 has an opening 2 for connection, as by soldering or a threaded connection, to a pipe connected to a valving system, such as a system containing valves 14.
The check valve 3 preferably is a ring valve as shown in FIG. 2, but it can take any shapes such as shown in FIG. 5, A, B, C. The valve 3 has a central divider 10 providing a surface acted on by fluid pressure so that the valve can be moved back and forth by application of fluid pressure on one end or the other end of said divider. Thus when the treating liquid is flowed into the housing 8 from the fluid passage opening 2 in a left to right direction in FIG. 1, the valve 3 is moved to the right to the position shown in broken lines in FIG. 1 thereby closing by-pass holes 5. This causes the entirety of the liquid to be directed through the casing 4, thereby forcing the balls 1 from the casing 4 through the membrane module 12. When the direction of fluid flow is reversed, the balls 1 at this time being in the other housing 8 at the opposite end of the membrane module, the liquid flowing through casing 4 will act on the opposite end of divider 10 to move the valve to the left in FIG. 1 to the position thereof shown in solid lines and the openings 5 are uncovered.
. As the barrier 7 there is usually employed a screen, but it can take any shapes such as shown in FIG. 4, which include net (FIG. 4, A), perforated plate (FIG. 4, B) and grid (FIG. 4, C or D). When the treating liquid is flowed into the casing 8 from the opening 9 in a right to left direction in FIG. 1, the barrier 7 prevents discharge of the rubbing and washing members 1 which move to the left as shown in FIG. 1. The barrier 7 permits flow of liquid into and out of the casing 4.
Two housings 8 are respectively connected by their openings 9 to the opposite ends of the reverse osmotic semipermeable membrane module 12. A prescribed number of sponge balls 1, three in the illustrated embodiment of the invention, are thereby made present in the fluid-flow system.
When a treating liquid under pressure is fed into one end of the fluid-flow system through the opening 2 in one of housings 8, the ring valve 3 adjacent that opening 2 is moved inwardly and the ring valve 3 in the other housing is moved outwardly by the pressure applied on the dividers (resistance elements) by the liquid. As a result, the by-pass hole 5 at the liquid inlet end of the system 12 is closed by its associated ring valve 3, whereas the by-pass hole 5 at the outlet end of the system is open. Hence, the majority or all of the treating liquid is caused to pass through the barrier 7 of the casing 4 at the fluid inlet end of the system, whereby the rubbing and washing members 1 are forcibly passed through the opening 9 and through the osmotic semipermeable membrane module 12.
The rubbing and washing members 1 are thereby moved through the module 12 to effect automatically the rubbing and cleaning of the inner surfaces of the module, under the hydraulic pressure of the treating liquid. The members 1 then enter the casing 8 at the liquid outlet end of the fluid-flow system and move into the casing 4 thereof where they are stopped by the screen 7. The ring valve 3 at the liquid outlet end of the fluid-flow system has already been moved outwardly by the pressure of the treating liquid before the entry of cleaning members 1 into the casing 4, whereby the bypass holes 5 of the casing 4 is thereby open. Thus, the treating liquid entering the housing 8 at the liquid outlet end of the system passes through the opening 9, the by-pass passage 6, the by-pass holes 5 and into the opening 2 at the liquid outlet end of the system. The rubbing and washing members 1 are stopped by the screen 7 at the discharge end of the system. The parts then remain in this condition until the direction of flow of the treating liquid through the module 12 is reversed. When the direction of flow of the treating liquid through the module 12 is reversed. reverse movement of the parts takes place.
Thus, when the permeation efficiency of such a system is reduced by contamination of the membrane after the reverse osmotic separation operation has been conducted for a certain time period, or when otherwise occasion demands, the direction of the liquid flow is reversed by reversing the liquid direction-changing valves 14, whereby to cause the members 1 to clean and scrub the inner surface of the membrane The treating liquid flow system includes a pump 13, a main flow control valve 15 and a reservoir or supply 16. Thus. when the apparatus is operated as described above. the rubbing and cleaning members 1 rub and wash the inner faces of the reverse osmotic membrane module 12 on each change of the direction of flow of the treating liquid and said members are moved into the casing 4 at the discharge end of the system.
The valve arrangement used for reversing the direction of flow of the treating liquid is not critical. The various valve arrangements described in Ser. No. 282 449 can be used. for example. In the illustrated embodiment of FIG. 3. in one direction of liquid flow through the membrane module 12, the valves 14b. 140 are open and valves 14a, 14d are closed. In the opposite direction of liquid flow valves 14a, 14d are open and valves 14b, 146 are closed. The valves can be opened and closed by hand or by an automatic cycle timer.
When the apparatus of the present invention is employed, the rubbing and cleaning operation can be performed simply at any time as occasion demands, by repeating the above procedures The membrane cleaning operation can be carried out by employing the treating liquid which is to be subjected to the reverse osmosis operation. Alternatively. a special washing liquid can be used to effect movement of the cleaning elements.
As described above, the rubbing and cleaning of the membrane can be performed by reversing the direction of the liquid flow, using the check valves 3. Therefore, the separation operation need not be interrupted for the rubbing and cleaning, and the separation operation can be conducted continuously. Further, when a control member such as a timer is employed for operating the liquid passage valves 14, automatic cyclic cleaning is possible.
in the present apparatus, since it is possible to use a structure in which the tubular osmotic membrane 12 can be directly attached to the openings 9 for the easings 8, the assembly can be made very compact.
Still further, by virtue of the above-mentioned characteristic features, the apparatus of the present device can be used not only for reverse osmotic systems but also for tubing systems in which slurries or precipitates frequently become present in the inner faces of the tubing, and these slurries or precipitates can easily be removed by rubbing and cleaning.
in the drawings, 17 represents a receiver for receiving purified water coming from the reverse osmosis module 12.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. In a fluid-flow system comprising a tubular piping arrangement having reversing valve means for reversing the direction of flow of fluid through the piping arrangement. one or more resiliently compressible objects movable back and forth through said piping arrangement to clean same. and retaining means adapted to retain said object or objects at the ends of the travel thereof through said piping arrangement, the improvement in which said retaining means comprises a container which is open at one end for receiving said objects from or directing said objects into said tubular piping arrangement and which is blocked at its opposite end by a porous barrier: by-pass conduit means connected in parallel with said container for by-passing liquid around said container; and check valve means coupled to the blocked end of the container and which is responsive to the direction of flow of liquid through said piping arrangement for movement between positions in which l) the liquid entering said tubular piping arrangement flows substantially entirely through said porous barrier and said container to force said object or objects through said piping arrangement. and (2) the liquid leaving said tubular piping arrangement flows into said container and then through said by-pass conduit means and said check valve means.
2. A fluid-flow system according to claim 1 in which said tubular piping arrangement comprises a tubular semipermeable membrane module.
3. A fluid-flow system according to claim 1 in which there are two retaining means respectively connected to opposite ends of said tubular piping arrangement.
4. A fluid-flow system according to claim 3, including a housing surrounding and radially spaced from said container with the space therebetween defining said by-pass conduit means, said housing having a first opening at one end thereof connected to said tubular piping arrangement and having a second opening at the other end thereof connected to said reversing valve means.
5. A fluid-flow system according to claim 4, in which said check valve means is disposed within said housing between said second opening of said housing and said porous barrier, said by-pass conduit means having one end in open communication with said first opening and having its other end extending beyond said porous barrier for communication through said check valve means with said second opening.
6. A fluid-flow system according to claim 5, in which said check valve is a slideable sleeve valve movable between positions opening and closing communication between said other end of said by-pass conduit means and said second opening.
7. A fluid-flow system according to claim 6, including a tube extending from said porous barrier across said other end of said by-pass conduit means, said tube having opening means therethrough, said sleeve valve being slideable axially inside said tube between positions opening and closing said opening means, said sleeve valve having a divider extending across the interior thereof for being acted on by the fluid flowing through the system.