Tank cleaning nozzle, tank comprising it and method for cleaning a tank

Abstract

A tank cleaning nozzle (2) configured to be mounted on a tank (6), wherein said tank cleaning nozzle (2) comprises an inlet (42), an outlet (26) and an interior space (54) being in fluid communication with the inlet (42) and the outlet (26), The tank cleaning nozzle (2) is configured to receive a pressurized liquid (36) through the inlet (42) and inject the liquid (36) through the outlet (26) into the tank (6), The tank cleaning nozzle (2) comprises a moveably arranged closing structure (34, 52) configured to close the outlet (26). The closing structure (34, 52) is arranged and configured to be moved into a position, in which the outlet (26) is provided with a free passage, through which the liquid (36) leaving the outlet (26) is injected into the interior space (54) without colliding with the closing structure (34, 52).

Claims

1. A tank cleaning nozzle configured to be mounted on a tank, wherein said tank cleaning nozzle comprises an inlet, an outlet and an interior space being in fluid communication with the inlet and the outlet, wherein the tank cleaning nozzle is configured to receive a pressurized liquid through the inlet and inject the liquid through the outlet into the tank, wherein the tank cleaning nozzle comprises a moveably arranged closing structure configured to close the outlet, wherein the closing structure is slidably arranged and configured to be moved into a first position within the interior space of the tank cleaning nozzle hereby providing a free passage to the outlet, through which the liquid leaving the outlet from within the interior space of the tank cleaning nozzle is injected into the interior space of the tank cleaning nozzle without colliding with the closing structure; and the closing structure is configured to be moved into a second position in which the closing structure sealingly abuts, and hereby closes the outlet, wherein the tank cleaning nozzle comprises a flange, that surrounds the outlet.

2. A tank cleaning nozzle according to claim 1, wherein the tank cleaning nozzle comprises a housing, wherein the housing comprises an inner wall in contact with the interior space of the tank nozzle, and a membrane attached to the inner wall of the housing or between bodies of the housing, wherein the closing structure is attached to the membrane and configured to be displaced between the first position and the second position and vice versa upon varying the force exerted to the membrane by the liquid inside the interior space.

3. A tank cleaning nozzle according to claim 1, wherein the tank cleaning nozzle comprises a housing ,wherein the closing structure is attached to the disk and configured to be displaced between the first position and the second position and vice versa upon varying the force exerted to the disk by the liquid inside the interior space.

4. A tank cleaning nozzle according to claim 2, wherein the membrane divides the interior space into: a first space being in fluid communication with the inlet and the outlet and a second space separated from the first space and not being in fluid communication with the inlet and the outlet, wherein the tank cleaning nozzle comprises a resilient member arranged in a manner in which the resilient member exerts a force on the membrane, the disk or the closing structure.

5. A tank cleaning nozzle according to claim 1, wherein the closing structure is a piston and the piston is arranged and configured to be moved into the interior space hereby opening the outlet.

6. A tank cleaning nozzle according to claim 5, wherein the housing comprises an interior space comprising a conical portion and a narrowing provided with the outlet.

7. A tank comprising a tank cleaning nozzle according to claim 1.

8. A tank according to claim 7, wherein the tank cleaning nozzle is arranged at the bottom portion, a top portion or a side wall of the tank.

9. A tank according to claim 7, wherein the tank cleaning nozzle is detachably attached to the tank.

10. A tank according to claim 9, wherein the tank cleaning nozzle is detachably attached to an attachment structure attached to the tank.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will become more fully understood from the detailed description given herein below. The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present invention. In the accompanying drawings:

(2) FIG. 1A shows a tank provided with a top mounted cleaning nozzle;

(3) FIG. 1B shows a prior art retractor configured to clean a structure inside a tank, wherein the retractor is in a closed configuration;

(4) FIG. 1C shows the prior art retractor shown in FIG. 1B in an open configuration;

(5) FIG. 2A shows a tank provided with a vertically arranged agitator and a plurality of prior art retractors;

(6) FIG. 2B shows a tank provided with a vertically arranged agitator and a bottom mounted prior art retractor;

(7) FIG. 2C shows a tank provided with a vertically arranged agitator and a bottom mounted tank cleaning nozzle according to the invention;

(8) FIG. 3A shows a cross-sectional view of a tank cleaning nozzle according to the invention in a closed configuration;

(9) FIG. 3B shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 3A in an open configuration;

(10) FIG. 3C shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 3B injecting a jet of cleaning liquid;

(11) FIG. 4A shows a cross-sectional view of a tank cleaning nozzle according to the invention in a closed configuration;

(12) FIG. 4B shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 4A, in an open configuration, in which a jet of cleaning liquid is injected by the tank cleaning nozzle;

(13) FIG. 4C shows a cross-sectional view of a two-piece tank cleaning nozzle according to the invention;

(14) FIG. 5A shows a cross-sectional view of a two-piece tank cleaning nozzle housing according to the invention in a disassembled configuration;

(15) FIG. 5B shows a cross-sectional view of the housing shown in FIG. 5A, in an assembled configuration;

(16) FIG. 5C shows a cross-sectional view of a two-piece tank cleaning nozzle according to the invention comprising an actuator arranged to displace a closing structure formed as a plug piston attached to the distal end of a rod, wherein the tank cleaning nozzle is in a closed configuration;

(17) FIG. 5D shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 5C, in an open configuration;

(18) FIG. 5E shows a cross-sectional view of a two-piece tank cleaning nozzle according to the invention in a closed configuration;

(19) FIG. 5F shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 5E, in an open configuration;

(20) FIG. 6A shows a cross-sectional view of a two-piece tank cleaning nozzle housing according to the invention in a disassembled configuration;

(21) FIG. 6B shows a cross-sectional view of the housing shown in FIG. 6A, in an assembled configuration;

(22) FIG. 6C shows a cross-sectional view of a two-piece tank cleaning nozzle according to the invention comprising an actuator arranged to displace a closing structure formed as a plug piston attached to the distal end of a rod, wherein the tank cleaning nozzle is in a closed configuration;

(23) FIG. 6D shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 6C, in an open configuration;

(24) FIG. 6E shows a cross-sectional view of a two-piece tank cleaning nozzle according to the invention in a closed configuration and

(25) FIG. 6F shows a cross-sectional view of the tank cleaning nozzle shown in FIG. 6E, in an open configuration.

DETAILED DESCRIPTION OF THE INVENTION

(26) Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, a tank cleaning nozzle 2 of the present invention is illustrated in FIG. 2C.

(27) FIG. 1A illustrates a tank 6 provided with a top mounted cleaning nozzle 8 connected to a pipe 14 through which cleaning liquid is provided to the cleaning nozzle 8. The cleaning nozzle 8 is spraying cleaning liquid 36 into the interior 20 of the tank 6. Hereby, the inside structures of the tank 6 including a rotatably mounted (at the upper portion 12 of the tank) agitator 4 is being cleaned.

(28) A drainage is provided in the lower portion 10 of the tank 6. A valve 18 is arranged to control the flow of cleaning liquid through an outlet pipe 16 connected to the lower portion 10 of the tank 6. A pump 22 is connected to the outlet pipe 16.

(29) The lower side of the impeller of the agitator 4 is not cleaned by the top mounted cleaning nozzle 8. The lower side that is not cleaned, is called shadow zone. Accordingly, an additional type of cleaning nozzle is required at the lower portion 10 of the tank 6 in order to clean the shadow zone.

(30) FIG. 1B illustrates a prior art retractor 50 configured to clean a structure inside a tank, wherein the retractor 50 is in a closed configuration. FIG. 1C illustrates the prior art retractor 50 shown in FIG. 1B in an open configuration.

(31) The retractor 50 comprises a body portion 28 and a cover member 34 covering an opening 26 in the retractor 50. The retractor 50 is attached to a wall 24 of a tank (not shown).

(32) In FIG. 1C, the cover member 34 of the retractor 50 has been displaced away from the body portion 28 into the tank (not shown) and cleaning liquid is sprayed into the tank. The cleaning liquid flows through the opening 26′ and is sprayed into a spray zone 30 indicated as a hatched area. The extension of cover member 34 causes generation of a cone-shaped shadow zone 32 extending (along the longitudinal axis of the body portion 28) in front of the cover member 34 in extension of the cover member 34.

(33) It is a major disadvantage, that the retractor 50 creates a shadow zone 32, because it makes it difficult to provide a desired cleaning of structures inside a tank.

(34) FIG. 2A illustrates a tank 6 provided with a vertically arranged agitator 4 and a plurality of prior art retractors 50. The retractors 50 are mounted in the side wall 24 of the tank 6. Two top mounted cleaning nozzles 8 are provided in the upper portion 12 of the tank 6.

(35) The agitator 4 comprises a vertically arranged rod member and four sets of side structures extending perpendicular to the rod member. Even though four retractors 50 are arranged to clean the underside of the side structures of the agitator 4, it can be seen that each of the retractors 50 spray cleaning liquid 36 into the interior of the tank and that a shadow zone 32 is created. The shadow zone 32 makes it very difficult to ensure that a satisfactory cleaning process has been carried out. Moreover, since the retractors 50 extend into the interior of the tank 6, there is a risk for collision between the retractors 50 and the structures of the agitator 4. Therefore, complex agitators are required to be shot off during the cleaning process.

(36) FIG. 2B illustrates a tank 6 provided with a vertically arranged agitator 4 and a bottom mounted prior art retractor 50. The agitator 4 comprises a rotatably mounted rod and impeller-shaped stirring structures attached thereto. The retractor 50 is supplied with liquid (preferably a suitable cleaning liquid) by a pump 62 connected to the retractor 50 through a pipe 64. It can be seen that the retractor 50 injects liquid 36 into a spray zone 30 located at the side portions of the tank 6 and that a shadow zone 32 is created. The shadow zone 32 is cone-shaped and extends from the cover member 34 of the retractor 50.

(37) FIG. 2C illustrates a tank 6 provided with a vertically arranged agitator 4 and a bottom mounted tank cleaning nozzle 2 according to the invention. The tank 6 basically corresponds to the one shown in FIG. 2B. The retractor 50, however, has been replaced by the tank cleaning nozzle 2 according to the invention.

(38) It can be seen that the tank cleaning nozzle 2 according to the invention is injecting liquid into the cone-shaped zone that was a shadow zone in FIG. 2B. Accordingly, the tank cleaning nozzle 2 is injecting liquid into a spray zone 30 positioned in the interior of the tank 6 in the same position as the shadow zone shown in FIG. 2B. If desired, it is possible to apply several tank cleaning nozzles 2 and to place them in appropriate positions on the tank to cover a larger area to be cleaned. It would also be possible to change the angular range of the cone-shaped spray zone 30.

(39) The agitator 4 comprises a vertically arranged rod having two impeller-shaped stirring members attached thereto. The tank cleaning nozzle 2 is attached to the outside of the wall of the tank 6. A pump 62 is connected to the tank cleaning nozzle 2 through a pile 64. Hereby, the pump 62 can deliver pressurized liquid to the tank cleaning nozzle 2.

(40) FIG. 3A illustrates a cross-sectional view of a tank cleaning nozzle 2 according to the invention in a closed configuration, wherein FIG. 3B illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 3A in an open configuration.

(41) The tank cleaning nozzle 2 comprises a housing 44 that may be made in any suitable material such as stainless steel. The housing 44 has a distal end provided with an opening 26 surrounded by a flange 38. The flange 38 may be attached to the wall of a tank by welding. Alternatively, the flange 38 may be mechanically attached to the wall of a tank e.g. by means of bolts.

(42) The tank cleaning nozzle 2 comprises a closing structure formed as a piston 52 provided in the distal end of a rod 53. The rod 53 extends through a bore 70 provided in the proximal end of the housing 44. The rod 53 is slidably arranged in the bore 70 and is configured to be displaced along its longitudinal axis X. Hereby, it is possible to displace the piston 52 in order to close and open the tank cleaning nozzle 2, respectively.

(43) A flexible and liquid tight membrane 56 is attached to the inner wall of the housing 44. The membrane 56 separates the interior space 54 of the housing 44 into a first space S.sub.1 and a second space 52. The rod 53 is attached to the membrane 56 by means of an attachment structure 71 providing a sealing attachment between the membrane 56 and the rod 53. Accordingly, when the membrane is moved it will cause displacement of the rod 53 and the piston 52 attached thereto.

(44) A resilient member formed as a spring 58 is attached to the bottom portion 68 of the housing 44. Alternatively, the spring 58 may be arranged to bear against the bottom portion 68 of the housing 44 without being attached thereto. In FIG. 3A, it can be seen that the spring 58 exerts an upright directed force B (indicated with arrows) on to the membrane 56.

(45) The tank cleaning nozzle 2 comprises an inlet 42 configured to be connected to a corresponding connection member (e.g. a pipe provided with a flange corresponding to the flange provided at the inlet 42 of the tank cleaning nozzle 2). When a pressurized liquid enters the inlet 42, the liquid will exert a downwards directed force A onto the membrane 56.

(46) In FIG. 3A, no liquid has entered the tank cleaning nozzle 2 through the inlet 42. Accordingly, the resulting force applied to the membrane will maintain it in a straight configuration, wherein the piston 52 is provided in its top position, in which the tank cleaning nozzle 2 is closed as long as the downwards directed force C exerted on to the piston 52 by the fluid (e.g. liquid) in the tank (not shown), to which the tank cleaning nozzle 2 is attached, does not exceed the upright directed force B.

(47) Accordingly, in order to secure that the tank cleaning nozzle 2 is kept closed the following relation must be fulfilled:
|B|>|C|  (1)
This means that the magnitude of the force B must be larger than the magnitude of the force C.

(48) In FIG. 3B, however, a liquid 36 flows into the first space S.sub.1 of the interior space 54 of the housing 44 through the inlet 42. Accordingly, the pressure of the liquid 36 exerts a downwardly directed force A onto the membrane 56. Since the magnitude of the downwardly directed force A exceeds the magnitude of the upwards directed force B exerted onto the membrane 56 by the spring 58, the resulting force will press the membrane 56 downwards as seen in FIG. 3B. Since the rod 53 is attached to the membrane 56, the rod 53 will be displaced in a direction towards the spring 58, which will be compressed. Accordingly, the following equation is fulfilled:
|A|>|B|  (2)
Accordingly, the rod 53 and the piston 52 provided in the distal end of the rod 53 will be displaced downwardly hereby creating an opening 26 in the distal end of the tank cleaning nozzle 2. The pressurised liquid 36 will be injected through the opening 26 hereby forming a cone-shaped spray zone 30 that contains no shadow zones.

(49) FIG. 3C illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 3B injecting a jet of cleaning liquid 36 into the interior of a tank comprising a wall 24, to which the tank cleaning nozzle 2 is attached.

(50) The tank cleaning nozzle 2 comprises a flange 38 that is attached to the outside side of the wall 24 by means of welding. It can be seen that the liquid 36 entering the inlet 42 that protrudes from the housing 44 presses the membrane downwards so that the piston 52 is displaced downwardly, whereby an opening 26 through which the liquid 36 can be injected, is created.

(51) FIG. 4A illustrates a cross-sectional view of a tank cleaning nozzle 2 according to the invention in a closed configuration. The tank cleaning nozzle 2 comprises a one-piece housing 44 provided with an inlet 42 surrounded by a flanged portion provided in the end of a tubular structure protruding from the housing 44. The housing 44 is provided with a distal portion provided with a flange 38 surrounding an outlet opening that is covered and closed by a plane plate-shaped door 40. The flange 38 is attached to the wall 24 of a tank (not shown).

(52) The door 40 is slidably arranged in a guide track provided in the flange 38. An actuator 46 is arranged close to the periphery of the flange 39. In one embodiment, the actuator 46 may be an electric actuator 46. In another embodiment, the actuator 46 may be a pneumatic actuator 46. In a further embodiment, the actuator 46 may be a hydraulic actuator 46.

(53) The actuator 46 is arranged and configured to displace the door 40 from a first position (shown in FIG. 4A), in which the door 40 covers and hereby sealingly closes the opening, into a second position (shown in FIG. 4B), in which the door 40 has been removed from the opening.

(54) The housing 44 comprises a conical portion 66 provided in the distal end of the housing 44. The width (diameter) D.sub.2 of the proximal end of the conical portion 66 is larger than the width (diameter) D.sub.1 of the distal end of the conical portion 66. Accordingly, the conical portion 66 tapers towards the opening provided in its distal end.

(55) FIG. 4B illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 4A, in an open configuration, in which a jet of cleaning liquid 36 is injected by the tank cleaning nozzle 2. It can be seen that the door 40 has been moved to the left side of the flange 38. Hereby, an opening, through which liquid 36 is being sprayed into the tank (not shown) is established.

(56) FIG. 4C illustrates a cross-sectional view of a two-piece tank cleaning nozzle 2 according to the invention. The tank cleaning nozzle 2 has a housing 44 comprising a portion that basically is shaped as a corresponding portion of the housing of the tank cleaning nozzle shown in FIG. 4A and FIG. 4B. The housing 44, however, comprises a portion configured to be attached to an attachment structure 60 that is adapted to be attached to a wall 24 of a tank (not shown).

(57) The attachment structure 60 may be attached to the wall 24 by any suitable means e.g. by means of welding or mechanical attachment techniques.

(58) The housing 44 may be detachably attached to the attachment structure 60 by using any suitable attachment means (not shown) providing a sealing attachment between the housing 44 and the attachment structure 60. It is possible to replace the housing 44 with another housing 44 in case of service or if a tank cleaning nozzle 2 having another capacity is required or desirable in an application.

(59) FIG. 5A illustrates a cross-sectional view of a two-piece tank cleaning nozzle housing 44 according to the invention in a disassembled configuration. The housing 44 comprises a distal portion provided with an opening 26 surrounded by a flange 38. The distal portion is furthermore provided with an attachment flange 72 provided with through bores, through which bolts 76 can be mounted.

(60) The housing 44 comprises a proximal portion provided with an inlet 42 surrounded by a flange. The proximal portion comprises an attachment flange 74 provided with threaded bores configured to receive the bolts 76. A sealing element 78 is arranged between the facing contact surfaces of the flanges 72, 74. The sealing element 78 is configured to be radially extended upon being axially compressed. Hereby, a sealing attachment of the proximal portion and the distal portion of the housing 44 can be achieved. The sealing element 78 may be an elastomer or be made in another suitable material. The sealing element 78 may be made in butadiene rubber, butyl rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, ethylene propylene diene monomer (EPDM), ethylene propylene rubber (EPR) or another rubber material by way of example.

(61) FIG. 5B illustrates a cross-sectional view of the housing 44 shown in FIG. 5A, in an assembled configuration, in which the matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, respectively, are screwed together by means of the bolts 76.

(62) FIG. 5C illustrates a cross-sectional view of a two-piece tank cleaning nozzle 2 according to the invention comprising an actuator 80 arranged to displace a closing structure formed as a plug piston 52 attached to the distal end of a rod 53. The tank cleaning nozzle 2 is in a closed configuration.

(63) A membrane 56 is attached to the inner walls of the housing 44 of the tank cleaning nozzle 2. The rod 53 extends through the membrane 56 and a sealing structure 73 seals the rod 53 relative to the membrane 56. Accordingly, the second space S.sub.2 will not receive liquid entering the first space S.sub.1 of the housing 44 through the inlet 42 of the housing 44. Accordingly, the first space S.sub.1 will not receive contaminants from second space S.sub.2.

(64) FIG. 5D illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 5C, in an open configuration. The rod 53 and the plug piston 52 attached to the distal end of the rod 53 is retracted into the interior of the housing 44 by means of the actuator 80 extending from the proximal end of the housing 44. Accordingly, the plug piston 52 attached is moved into a position in the first space S.sub.1, whereby an opening 26 is revealed in the distal portion of the housing 44. The actuator 80 may be controlled by a control unit 82. The actuator 80 may be energised by the control unit 82 or by another energy source (not shown). Liquid 36 in the interior space of the housing 44 is sprayed out through the opening 26.

(65) FIG. 5E illustrates a cross-sectional view of a two-piece tank cleaning nozzle 2 according to the invention in a closed configuration. The tank cleaning nozzle 2 comprises a receiving portion 84 provided in the proximal end of the housing 44 of the tank cleaning nozzle 2. The receiving portion 84 is configured to receive the end of a rod 53 slidably arranged in the housing 44. A semi-spherical piston 52 is attached to the other end of the rod 53. A membrane 56 divides the inner space of the housing 44 into a first space S.sub.1 and a second space S.sub.2.

(66) An inlet 42 is provided at the end of a flanged tubular structure protruding from one of the walls of the housing 44. Liquid entering the housing through the inlet 42 flows through the first space S.sub.1, wherein the liquid tight membrane 56 prevents liquid from entering the second space S.sub.2. Accordingly, the first space S.sub.1 will not receive contaminants from second space S.sub.2.

(67) The membrane 56 is attached to the rod 53 by means of an attachment structure 71. A spring 58 is arranged between the membrane 56 and the proximal inner wall portion of the housing 44. The spring is wound around the rod 58.

(68) In FIG. 5E, the piston 52 abuts the distal portion of the housing 44 and seals against the outlet opening of the housing 44. No liquid is present inside the housing and therefore, the upward directed force exerted by the spring 58 onto the membrane 56 exceeds the downwardly directed force exerted on the free end of the piston 52 by the liquid in the interior of the tank (not shown). Accordingly, the tank cleaning nozzle 2 is in a closed configuration.

(69) FIG. 5F illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 5E, in an open configuration. The first space S.sub.1 of the housing 44 is filled with a cleaning liquid 36 that is injected into the tank (not shown), to which the tank cleaning nozzle 2 is attached. The pressure of the liquid 36 causes a downwardly directed force that moves the membrane 56 and compresses the spring 58. Accordingly, the rod 53 is moved further into the receiving portion 84. The motion of the rod 53 displaced the piston 52 and created an opening 26 (surrounded by a flange 38) in the distal portion of the housing 44. Therefore, the liquid 36 is injected into the tank while forming a cone-shaped jet extending from the opening 26.

(70) FIG. 6A illustrates a cross-sectional view of the housing 44 that basically corresponds to the one shown in FIG. 5A. The housing 44 comprises a distal portion provided with an opening 26 surrounded by a flange 38. The distal portion is furthermore provided with an attachment flange 72. The flanges 72, 74 are configured to be attached to each other by means of a hose clamp as shown in FIG. 6B.

(71) FIG. 6B illustrates a cross-sectional view of the housing 44 shown in FIG. 6A, in an assembled configuration, in which the matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, respectively, are attached to each other by means of a clamp 77.

(72) FIG. 6C illustrates a cross-sectional view of a two-piece tank cleaning nozzle 2 according to the invention basically corresponding to the one shown in FIG. 5C. The matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, are attached to each other by means of a clamp 77.

(73) FIG. 6D illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 6C, in an open configuration. FIG. 6D basically corresponds to FIG. 5D. The matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, however, are attached to each other by means of a clamp 77.

(74) FIG. 6E illustrates a cross-sectional view of a two-piece tank cleaning nozzle 2 according to the invention in a closed configuration. FIG. 6E basically corresponds to FIG. 5E. The matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, however, are attached to each other by means of a clamp 77.

(75) FIG. 6F illustrates a cross-sectional view of the tank cleaning nozzle 2 shown in FIG. 6E, in an open configuration. FIG. 6F basically corresponds to FIG. 5F. The matching flanges 72, 74 of the proximal portion and the distal portion of the housing 44, however, are attached to each other by means of a clamp 77.

LIST OF REFERENCE NUMERALS

(76) 2 Tank cleaning nozzle 4 Agitator 5 Rod 6 Tank 8 Nozzle 10 Lower portion 12 Upper portion 14 Pipe 16 Pipe 18 Valve 20 Interior (space) 22 Pump 24 Wall 26, 26′ Opening 28 Body 30 Spray zone 32 Shadow zone 34 Cover member 36 Liquid 38 Flange 40 Door 42 Inlet 44 Housing 46 Actuator 50 Retractor 52 Piston (closing structure) 53 Rod 54 Interior space 56 Membrane 58 Spring 60 Attachment structure 62 Pump 64 Pipe 66 Conical portion 68 Bottom portion 70 Bore 71 Attachment structure 72 Flange 73 Sealing structure 74 Flange 76 Bolt 77 Clamp 78 Sealing element 80 Actuator 82 Control unit 84 Receiving portion X Axis D.sub.1, D.sub.2 Width (diameter) S.sub.1 First space S.sub.2 Second space A, B, C Force