US 3719191 A
A single service cleaning system utilizes a motive tank within a rinse water tank. Pipe lines interconnect the tanks with each other and with the tank or product-pipeline to be cleaned, a supply pump being used to pump liquid under control of a burst valve to the tank lines to be cleaned, with a motive pump pumping motive fluid from the motive tank through an eductor to draw returned liquid from the tank to be cleaned for return into the motive tank and/or for discharge through a drain line. Steam may be admitted to the system prior to the liquid entering both pumps for raising the temperature of the water in the system. Chemicals may be selectively introduced into the feed line leading to the tank or product-pipeline to be cleaned and various valves control the flow for different cleaning cycles. There is also an air supply for blowing liquid out to evacuate the feed line.
Claims available in
Description (OCR text may contain errors)
United States Patent Zimmerly 1 March 6, 1973 1 CLEANING SYSTEM Primary Examiner-Robert L. Bleutge  lnventor. Robert D. Z1mmerly, Kenosha, WIS. A0mey MOrSen & Morse"  Assignee: Ladish C0., Cudahy, Wis. 22 Filed: Feb. 4, 1971  ABSTRACT [21 1 Appl. Na: 112,744 A single service cleaning system utilizes a motive tank within a rinse water tank. Pipe lines interconnect the tanks with each other and with the tank or product-  US. Cl. ..l34/102, 134/21, 134/103, pipeline to be cleaned, a supply pump being used to 134/ 168 R pump liquid under control of a burst valve to the tank  Int. Cl. ..B08b 9/08, 1308b 3/02 lines to be cleaned, with a motive pump pumping mo-  Field of Search ..l34/2l 24, 95, 98, 99, 100, tive fluid from the motive tank through an eductor to 134/101, 102, 103, 168 R, 169 R, 171 draw returned liquid from the tank to be cleaned for return into the motive tank and/or for discharge  References Cited through a drain line. Steam may be admitted to the system prior to the liquid entering both pumps for UNITED STATES PATENTS raising the temperature of the water in the system. 3,022,792 2/1962 Perkins ..134/168 R Chemicals may be Selectively introduced into the feed 2,896,643 7/1959 Ottoson... ...l34/168RX line leading to the tank or P -P p to be 3,062,188 11/1962 O'Day ,134/100X cleaned and various valves control the flow for dif- 2,018,757 10/1935 Butterworth ..134/169 R X ferent cleaning cycles. There is also an air supply for 3,042,553 7/1962 Kearney et al. ..l34/l69 R X blowing liquid out to evacuate the feed line 3,013,665 12/1961 Schmidt et al. ...134/l68 R X 3,419,023 12/1968 Valdes ino ..134/101 10 Claims, 1 Drawing Figure Q0 'JOQQQQ 3 PATENTED 6 [975 Nb Q r a Qh mw &
ATTORNEYS O WE INVENTOR WA MZZ 0 GGGGGGGG OOOOOOOOO CLEANING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This system may be used to clean liquid tanks or product-pipelines, and is particularly useful in connection with liquid food tanks such as stationary milk tanks or milk tanks mounted on vehicles.
2. Description of the Prior Art Heretofore tank clean-in-place systems have been proposed in Seeley U.S. Pat. No. 3,448,745 wherein there are two separate tanks, one containing a rinse liquid and the other containing a detergent liquid. In this type of system the detergent is reused. While such a system may be satisfactory for certain types of uses where the degree of soil in the tanks or productpipelines is minimal, it is not satisfactory in many 'cases where very dirty tanks are encountered. Furthermore, one system of the Seeley patent requires the use of a flow splitter which has an inlet connected to a pump outlet, and outlets connected to'the feed conduit and to the eductor inlet. It also requires additional valves and is expensive to crate, ship, rig and uncrate,-andrequires a substantial amount of time to install. In addition, it takes up a relatively large amount of floor-space.
SUMMARY OF THE INVENTION The present invention provides a single service tank cleaning system which has a motive tank preferablyarranged within a rinse water tank and which has 'pipe lines interconnecting the tanks with each other and connectible with the tank or product-pipeline to be cleaned, there being a supply pump to pump liquid, under the control of a burst valve, to the tank or line to be cleaned, and there being a motive pump for pumping motive fluid from the motive 'tankthroughan-eductor to draw returned liquid from the tank to be cleaned for return to the motive tank and/or for discharge through a drain line. v
A general object of the invention is to provide a single service clean-in-place tank cleaning system which is compact in size, which is self-contained in that it can be assembled on one base, which is inexpensive to crate,
ship, rig and uncrate, and which requires a minimumof time to install.
A further object of the invention is to provide a system wherein there is a single motive tank located within a rinse tank to provide a compact installation and one which eliminates thermal shock in that the wash solution is heated gradually.
A further object of the invention is to provide a single service tank cleaning system wherein there is an eductor return from the service tank whereby fewer pumps are needed, which makes it possible to pump out service tanks where the outlets are too near the floor to provide adequate pitch to a return pump, which simplifies the return system, and which eliminates air relief valves and the hazard of hot chemicals spurting from valves.
A more specific object of the invention isto provide a single service system wherein foam in the service tank is removed by means of the eductor vacuum.
A further object of the invention is to provide a system wherein the tank may be cleaned with the lowest possible level of cleaning solution flooding the tank outlet.
A further object of the invention is to provide a system wherein a motive pump for the eductor may be employed to fill the motive tank to provide for a quicker fill when desired.
A further object of the invention is to provide a system wherein, on pump-out of the system, it is possible to leave the burst valve open and applycompressed air to blow liquid out of the feed line to evacuate the latter.
A further object of the invention is to provide a sin- ,gle'servicesystem which is versatile in use and which is capable of handling tanks which are dirtier than normal.
With the above and other objects in view, the invention consists of the improved tank or product-pipeline cleaning system, and all of its parts and combinations, as set forthin the claims, and all equivalents thereof.
BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing, illustrating one completeembodiment of the preferred form of the invention, the FIGURE is a schematic view of the tank cleaning system.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawing, the numeral 10 designates a service tank such as a stationa- .ry'milk tank. This may, however, be a tank mounted on a transportation vehicle, a silo tank, a cooking vat, or any other container requiring clean-in-place tank or product-pipeline cleaning action.
The improved clean-in-place installation includes an outer rinse'tank l 1 adapted to contain water with a motive tank 12 positioned therein. The motive tank is preferably spaced a substantial distance above the bottom of the rinse tank and is of such diameter that there is a substantial space all around the motive tank within the rinse tank. Leading from the bottom of the rinse tank 11 is an outlet line 13 leading to the rinse tank outlet valve 14. The valve 14 may have a valve member 15 therein capable of closing the outlet from the rinse tank. The valve 15 may be operated in any desired manner. An air-actuated cylinder 16 is illustrated which may be actuated by compressed air under control of a suitable valve either manually or automatically operable. An outlet line 17 leads from the bottom of the motive tank 12 and connects with a motive tank outlet valve 18. The latter has a valve member 19 therein which is capable of closing off return from the motive tank. The valve 19 may be operated by a pneumatic cylinder 20 or in any other manner. The cylinder 20 may be connected with a source of compressed air under control of a suitable valve. The horizontal branches of the valves 14 and 18 are connected to one another at 21. ln addition, an air supply line 22 leading from a suitable source 23 of compressed air connects with the valve 18 .as illustrated, there being a nonretum check valve at 24 and a control valve 25 in the pump connects with aburst valve 28 of any well-known type which is under the control of a pneumatic actuator 29 which maybe programmed or otherwise operated to cause the burst valve to open and close at regular predetermined intervals or to remain open in certain situations. The outlet of the burst valve connects with a continuation 30 of the feed line, which may be connected by a hose or other conduit 31 with a spray head 32 within the service tank or may be connected to a product-pipeline such as might be interposed between lines 30 and 42. In the claims the term service installation contemplates either a service tank or a productpipeline. A branch line 33 from the burst valve may connect with suitable temperature control sensors. Chemical pumps, such as the pump 34 which connects with a chlorine tank, the pump 35 which connects with an alkali tank, and the pump 36 which connects with a polyphosphate tank, may supply chemicals when required through lines 37, 38 and 39 to the feed line 26. Another line 40 connecting with a pump 41 may supply acid to the line 26 when required.
The return from the service tank or product-pipeline is by way of a suitable conduit 42 connected with the bottom of the supply tank, and connecting with a return line 43. The line 43 connects with a suction inlet 44 of an eductor 45. The outlet from the eductor connects with a line 46 leading to a combination return and drain valve 47. The latter valve may be suitably controlled, preferably by a pneumatic actuator 48, to direct liquid from the line 46 either into the motive tank 12 or into the drain line 49 leading to a floor drain 50.
A motive pump 51 for the eductor has its inlet connected by a line 52 with the discharge line 17 from the motive tank 12 through a suitable connector fitting 53. Steam from a line 54, under control of a valve 55, also connects with the fitting 53 to supply steam to the lines 52 and 17 when required.
Outlet from the motive pump 51 connects with a line 56 leading to the motive fluid inlet of the eductor, there being a check valve 57 in the line 56. The check valve 57 is used in line cleaning where the motive pump 51 is not run and when fluid is pumped by the supply pump 27 through the closed loop back to the motive pump. In this type of operation suction is not required.
Fresh water from a supply line 58 is conveyed by a line 59 to a spray head 60 within the motive tank, there being a valve 61 in the line 59. Fresh water may also be directed when required through line 62 into the rinse tank 1 1 under control of a valve 63. Within the motive tank are probes 64 and 66,- and within the rinse tank are probes 67 and 68.
OPERATION The first procedure is to flush clear water through the system. With the motive tank 12 initially empty and with the rinse tank 11 full of water, the valves and 19 are opened to cause water from the rinse tank 11 to flow under the head of the tank through the lines 13 and 17 into the motive tank. Next, both the supply pump 27 and the motive pump 51 are started. Water is then pumped from both the motive tank and the rinse tank. The water from the rinse tank is pumped through the lines 13, 26 and 30 into the service tank or productpipeline under control of the preferably automatically operated burst valve 28. This valve may be set for any time interval, but it is preferred to have it onfor 15 seconds and then off for 10 seconds. Thus this alternating of the valve gives bursts of fluid into the service tank 10 to provide impact against the walls of the tank for removing clinging material and thus thoroughly rinse the service tank.
The force of water pumped through the eductor 45 by the motive pump 51 creates a vacuum in the return line 43 which pulls the fluid out of the service tank into the return line. If the service tank or product-pipeline is quite dirty the valve 47 is operated to direct the dirty water through the line 49 into the floor drain rather than into the motive tank through line 70. If the water in the return line 43 is not too dirty, or after it has been discharged into the drain for a long enough time to get rid of the major dirt, then the valve 47 is operated to direct the return liquid from line 46 into the top of the motive tank 12 in a recycling operation. During such recycling the valve 15 is closed to prevent fresh water being circulated.
After the preliminary flush operation, a prerinse may be carried out. This can be accomplished by closing the valve 15 and opening the valve 19 so that liquid from only the motive tank 11 is circulated in both directions, i.e., part of the liquid is pumped by the pump 27 through the line 30 leading to the service tank for rinsing, and part of the liquid from the motive tank is drawn through the line 52 by the pump 51 to give motive power for the eductor 45, this liquid returning through the valve 47 to the motive tank. During this particular type of operation the burst valve 29 may be operating in an alternating manner or it maybe inactive to allow continuous flow to the service tank or a product-pipeline, depending upon requirements. The operation of the motive pump during this part of the cycle acts on the eductor 45 to pull back through the return line an amount of liquid to compensate for the amount which is entering the service tank from the line 30. When the eductor is running at full capacity it generally requires 120-130 gallons per minute, for the average dairy use, and provides sufficient suction to assure return of the amount of liquid necessary to clean the tank, 100 gallons a minute for over-the-road tanks, and gallons a minute for silo tanks. The pumps 27 and 51 are sized to be capable of equal flow. This circulation of the semi-dirty water during the pre-rinse cycle usually continues for l to 2 minutes.
The next operation is a pump-out operation, the purpose of which is to get rid of the dirty water. During this operation the burst valve 28 is closed to stop flow to the service tank 10. Then the water from the service tank 10 is sucked by the eductor 45 through line 46 into the motive tank and is merely recirculated through the motive system comprising the motive tank 12, lines 17 and 52, pump 51, and lines 56, 46 and 70.
Probes 64 and 66 in the motive tank of any wellknown type control, preferably through well-known electrical controls, the operation of the pneumatic valve 47 to maintain the level in the motive tank and insure that all liquid has returned from the service tank to the motive tank. In this control operation, whenever returning liquid in the line 46 causes the liquid level in the motive tank 12 to rise above the level of the probe 64, this will cause opening of the valve 47 through the pneumatic actuator 48 using any suitable solenoid-actuated control valve of any well-known type. This allows wa t-n from the line 46 to go out of the drain line 49 to prevent ovcrfilling of the motive tank. The valve 47 stays open to the drain line until the liquid in the motive tank 12 drops to the level of the probe 66. This step is repeated until all liquid is returned from the service tank. Themall liquid left in the motive tank is pumped to the drain. If, after this pumping-out of the motive tank, any foam is left in the motive tank, the valve 61 may be opened to supply fresh water to the spray head 60 to rinse the foam down the drain.
The next procedure is the wash cycle. At the start of the wash cycle the valves 15 and 19 are both opened to refill the system with fresh water, the valve 63 having been opened to keep the rinse tank full. With a programmed system the valve 63 is under the control of the probes 67 and 68 by any well-known means. If the level of liquid in the rinse tank is below the level of the probe 68 the valve 63 will automatically turn on the fresh water supply. When the level in the rinse tank reaches the probe 67 the valve 63 will automatically shut off. Thus, in practical operation the rinse tank is automatically maintained full. This could, of course, be done manually.
With the valve 15 open, the entire system is filled until the level in the motive tank reaches a prescribed level. When this occurs the valve 15 is shut and the liquid is being circulated in both directions by the pumps 27 and 51, Le. the rinse tank liquid is delivered by pump 27 into the service tank and the motive tank liquid is delivered toward the right through the eductor 45.
When the system reaches equilibrium the rinse tank is closed off with valve 14 and the motive tank 12 now supplies both pumps. The steam valve 55 is then opened and left open until it heats the entire system to l35160F., depending upon the particular application. It is an important feature of the present invention that the water circulating in the motive tank transfers heat to the water being stored in the rinse tank. With the rinse tank starting out with say 40 F. water, the 160 F. water in the motive tank will preheat the rinse water due to the fact that the motive tank is within the rinse tank. Thus the rinse water is preheated to 100 F. for example. Thus 100 F. water is delivered to the service tank, eliminating thermal shock in the service tank and equipment. Thermal shock can cause collapse of service tanks.
After the system has been heated to a desired temperature the steam valve may be turned off. The different chemicals may be introduced to the feed line 26 during the heating process by operating the pumps 34, 35 and 36 to introduce chlorine, alkali, or polyphosphates or other selected chemicals to the system. The water is circulated through the service tank or product-pipeline for five to forty-five minutes, depending upon the application.
After the washing cycle has been completed it is usual to have a pump-out to evacuate the system. This may be accomplished, as heretofore described, by causing the suction in line 43 created by the eductor 45 to pump out the service tank, and if the valve 47 is open which is like the original preliminary flush. Here botlz valves 15 and 19 are opened to cause liquid from the rinse tank to flood the system with clear water to get rid of chemicals and residues from the service tank and from the system. This flooding may be repeated, establishing circulation in the system, with fresh water being added until a predetermined level is obtained in the motive tank. The post-rinse is continued for a short period of time (2 to 3 minutes) and then all water is pumped to drain in an operation similar to the pumpout at the conclusion of the wash cycle. The purpose is to rinse out all traces of the chemicals used in the wash cycle prior to the final acid rinse.
In the final acid rinse cycle water is added to the system as in previous cycles until equilibrium of the water level in the motive tank 12 is reached and circ'ulation is established.
Thereafter the acid pump 41 may be started to add acid through the line 40 in a prescribed amount, and the acid is circulated in the system for three to five minutes. After the acid circulation the pump-down heretofore described may be repeated, followed by another air blow from the compressed air line 22 to again evacuate liquid from the feed line.
It is apparent from the above that, at the end of the cycles, all of the liquid is discarded through the drain. Thus this system is particularly suited where tanks are quite dirty, the clean-in-place system being then completely clean for the next use. It is apparent from the above description that the improved system where the motive tank is located within the rinse tank, provides compactness, occupying a minimum of floor space, and may be quickly installed. It is also apparent that a very flexible system has been provided suitable for numerous types of cleaning operations while nevertheless including relatively few parts, with a minimum of valves, and only two pumps.
It is to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur' to a person skilled in the art.
What I claim is:
1. A cleaning system for a service installation comprising: a rinse tank for a rinsing liquid, an outlet line from said rinse tank, a motive tank for said liquid, an outlet line leading from the motive tank, a feed line for conveying said liquid from the outlet line of the rinse tank to the service installation, a supply pump in said feed line, a return line adapted to return liquid from said service installation, an eductor having a suction opening connected to said return line, means including a motive pump for delivering liquid from said outlet line of said motive tank through said eductor to create a suction in said return line and draw liquid from the service installation, means for selectively delivering said motive liquid and returned liquid either back into said motive tank or to a point of drain, valve controlled bility of thermal shock in the service tank.
means for delivering fresh water to said tanks, and
valve controlled means for delivering chemicals to the system.
2. A cleaning system asclaimed in claim 1 in which the motive tank is smaller than and positioned within said rinse tank to be surrounded by the liquid therein.
3. A cleaning system as claimed in claim 2 in which there is means for heating the liquid being supplied to i I the system and motive tank whereby the surrounding water in the rinse tank' is'heated by contact with the motive tank to a temperature lower than the temperathere is a valve controlling the flow of rinse liquid from the rinse tank, and wherein there is a connected valve; br'i'ti'o lliri'g'f'cbriiiiiunication between the outlet line: fromv the motive tank and the feed line for the service; installation, said connected valves also providing for optional intercommunication between the outlet line 1 from the rinse tank and the outlet line from the motive tank.
7. A cleaning system as claimed in claim 6 in which 1 there is means for directing compressed air through the connected valves and into the feed line to blow liquid out of the latter.
8. A cleaning system as claim'ed'in claimflhin which 1 j there is a drain line and a combination drain and return valve for directing the flow of return liquid'and'm'otive liquideither back into the motive tank or into the'drain line. I
cleaning system as claimed in claim '1 in which there is means for selectively directing compressed air into the 'feed line to blow liquid out of the latter.
10. A cleaning system as claimed in claim 1 in which there is valve controlled communication between the' outlet line from the motive tank and the feed line for the service installation, and in which the means. for delivering liquid from the motive tank through the eductor is upstream in said outlet line from the valve controlled communication with the feed line.