A cleaning system for cleaning a plurality of service tanks located at different sites spaced widely apart from each other. A set of storage tanks is located at one site, for storing cleaning solutions, each cleaning solution being recirculated through a respective recirculating line from each storage tank. The cleaning system further includes cleaning stations, one for each service tank assembly, each located close to its respective service tank assembly, each cleaning station having a connection to each recirculating line. Each cleaning station includes a wash/motive tank for a washing liquid, a rinse tank for a rinsing liquid, and an outlet line leading from each of the wash/motive tank and the rinse tank. Liquid is conveyed from the outlet lines of the wash/motive tank and rinse tank to the respective service tank assembly via a feed line. A return line is adapted to return liquid from the respective service tank assembly. An eductor has a vacuum opening connected to the return line. A motive pump delivers liquid from the outlet line of the wash/motive tank through the eductor to create a vacuum in the return line and draw liquid from the service tank assembly. Also included is a method of cleaning the service tank assemblies by use of the cleaning stations.

BACKGROUND OF THE INVENTION 
This invention relates to clean-in-place systems, that is, systems for 
cleaning sanitary distribution systems without disassembly, and in 
particular to such cleaning systems that to not require separate 
full-sized storage tanks for each tank to be cleaned. 
Conventional clean-in-place systems use a complete set of large cleaning 
solution storage tanks for each service tank to be cleaned. This system 
requires a large capital investment and is inefficient, not only because 
it entails the storage of large amounts of cleaning solutions for each 
service tank to be cleaned, but also because it takes up large amounts of 
floor space to have multiple sets of these large storage tanks in various 
different parts of the plant. 
One solution to the space problem is posed by Zimmerly, U.S. Pat. No. 
3,719,191, wherein the motive tank is positioned within the rinse tank. 
This design, however, does not address the inefficiency of storing large 
amounts of cleaning solution at a number of different locations, and still 
requires a large capital investment. 
A solution to the latter problem has been to employ portable cleaning 
systems, which require reduced capital investments, and are particularly 
beneficial for use with new product and/or process developments. Once a 
process or product is established, though, the limits of the portable 
units become apparent. Portable units are generally smaller in size and 
require manual connections of all utilities at each user location. This 
requirement of disconnection and re-connection of utilities reduces the 
convenience of the portable units. Further, the capacities of the portable 
units may come into question in relation to the service tank and 
associated system to be cleaned. Often the equipment being cleaned 
requires greater volumes or higher flow rates than the portable unit can 
supply. 
This invention relates to improvements over the apparatus set forth above 
and to solutions to the problems raised or not solved thereby. 
SUMMARY OF THE INVENTION 
The invention includes a cleaning system for cleaning a plurality of 
service tank assemblies located at different sites spaced widely apart 
from each other. For purposes of this description, each service tank 
assembly includes the service tank itself, and associated control valves 
and hydraulic circuitry. According to the invention, the cleaning system 
includes a single set of storage tanks, located substantially at one site, 
for storing various cleaning solutions. Each tank has its own respective 
recirculating line, through which its respective solution is continuously 
recirculated. The cleaning system further includes a plurality of cleaning 
stations, one for each service tank assembly, each cleaning station 
located relatively close to its respective service tank assembly, each 
cleaning station having a connection to each recirculating line. Each 
cleaning station includes a wash/motive tank for a washing liquid, a rinse 
tank for a rinsing liquid, and an outlet line leading from each of the 
wash/motive tank and the rinse tank. A feed line, having a supply pump in 
the line, is provided for conveying liquid from either the rinse tank or 
the wash/motive tank to the respective service tank assembly. A return 
line is adapted to return liquid from the respective service tank 
assembly. An eductor has a vacuum opening connected to the return line. A 
motive pump delivers liquid from the outlet line of the wash/motive tank 
through the eductor to create a vacuum in the return line and draw liquid 
from the service tank assembly. Means are provided for selectively 
delivering the motive liquid and returned liquid either back into the 
wash/motive tank or to a point of drain or other disposal. Valves control 
the flow of the cleaning solutions from the recirculating lines to the 
rinse and wash/motive tanks. Heating devices, such as heat exchangers, are 
provided in the recirculating lines and in the feed lines, for adding heat 
to the cleaning solution in those lines. A control mechanism is provided 
for controlling the valves and pumps to permit flow of cleaning solution 
as necessary to clean the service tank assembly. 
The invention also includes a method of cleaning the service tank 
assemblies, including rinsing water through the washing circuit and 
service tank assembly, circulating wash solution through the wash/motive 
tank and water through the rinse tank, thereby washing the equipment that 
will be washing the service tank assembly, permitting inflow of wash 
solution into the wash/motive tank and the service tank assembly, 
circulating the wash solution throughout the service tank assembly, 
permitting the used wash solution to exit the service tank assembly, 
rinsing the service tank assembly with pure water, and using compressed 
air to empty all liquid from the service tank assembly. 
Other objects and advantages of the invention will become apparent 
hereinafter.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawing figures, there are shown several service tanks 
10. These service tanks could be any mix of two or more of any of 
stationary milk tanks or pharmaceutical or soft drink distribution tanks, 
tanks mounted on a transportation vehicles, silo tanks, cooking vats, or 
any other containers or enclosures requiring clean-in-place container or 
product-pipeline cleaning action. 
The invention provides a clean-in-place system 12 to clean the service 
tanks 10 and the associated piping, valve and control mechanisms, 
hereinafter collectively referred to as tank circuits 14. According to the 
invention, the clean-in-place system 12 includes a set of large storage 
tanks 16 for storing the various types of cleaning solutions. For 
instance, depending on the type of materials to be cleaned out of the 
tanks, there may be acid wash solutions, caustic wash solutions, soft 
water, water for injection (that is, treated water), pH balance solutions, 
Cl-caustic wash solutions, and others. Each of these solutions will be 
stored in a separate storage tank 16a, 16b, 16c, 16d, and so on, with the 
number of storage tanks being supplied according to the cleaning 
requirements, and the number of different solutions required, in the plant 
where the cleaning system is installed. It would not be unusual that these 
storage tanks 16 would be 200 to 250 gallons in size. Generally these 
storage tanks 16 would be located together in a substantially single site 
within the plant. 
A recirculating pump 18a, 18b, 18c, 18d, is supplied for each of the 
storage tanks 16, for pumping solution from each tank into a respective 
recirculating line 20a, 20b, 20c, 20d. Each respective recirculating line 
20 eventually empties into the respective tank 16 from which its solution 
originated. Heating devices, such as heat exchangers 22a, 22b, 22c, 22d, 
may be supplied in the recirculating lines to add heat, if necessary, to 
maintain the temperature of the solutions at a predetermined level. Of 
course a source of steam 24 or other heat energy would be supplied to the 
heat exchangers 22 to provide the necessary heat. 
The recirculating lines 20 carry the necessary cleaning solutions to a 
number of cleaning stations 26, corresponding in number to the number of 
service tanks 10 to be cleaned. Each of the cleaning stations 26 is 
located near to its respective service tank 10, and is provided with a 
connector/control 28 to the recirculating lines 20. The purpose of 
connector/control 28 is to permit or prevent flow of the solutions from 
the recirculating lines 20 into the cleaning station 26. Since each of the 
cleaning stations 26 is substantially identical to the others, other than 
perhaps the type of service tank with which it is associated, the detail 
of the one cleaning station 26 shown in FIG. 2 describes them all. 
Each of the cleaning stations 26 includes a pair of tanks, one a 
wash/motive tank 30 and the other a rinse tank 32. These tanks are 
preferably formed of stainless steel and may be very similar in size, 
preferably in the range of forty to fifty gallons. For ease of 
manufacture, these tanks may be formed by cutting lengths of stainless 
tubing, for example 24 inches in diameter, and cut to a predetermined 
length to obtain the desired volume. The ends may then be closed by any 
suitable means, such as clamping flat plates (not shown), sized to fit, 
over the open ends in a conventional manner. 
In the preferred embodiment shown in FIG. 2, the rinse tank 32 has an 
outlet 34 at the bottom, and the wash/motive tank 30 has two outlets 36, 
38 at its bottom. Rinse tank outlet 34 and one motive tank outlet 36 are 
separately controlled by valves 40, 42, which control flow of solution 
from those tanks to a CIP supply pump 44. Supply pump 44 pumps the 
solution it receives to the service tank 10 via a feed line 46. A 
supplemental wash tank 47, which contains wash chemical suitable for the 
intended purpose, may also be provided, connected to the inlet side of 
supply pump 44. The flow of wash chemical from supplemental tank 47 to 
supply pump 44 is controlled by supplemental wash valve 47a, and permits 
the addition of a greater concentration of wash chemical if that is 
desired for a particular application. A heating device, such as a heat 
exchanger 48, is added in the feed line 46 to add additional heat to the 
solution on its way to the service tank 10. 
Both the rinse tank 32 and the wash/motive tank 30 have inlet lines 50, 52 
permitting inflow of solution from the recirculating lines 20. In 
addition, wash/motive tank 30 has an inlet line 54 from feed line 46, 
controlled by a valve 56. The second outlet 38 from the wash/motive tank 
30 leads to a motive pump 58, which pumps solution from the wash/motive 
tank 30 to the motive fluid inlet 60 of an eductor 62. Eductor 62 also has 
a vacuum inlet 64, which is connected to a return line 66 from the service 
tank 10. The outlet of eductor 62 leads to control valves 68, 70 which can 
either permit the solution to return to the wash/motive tank 30, or send 
the solution to drain. If necessary or desirable, instead of letting the 
solution run to drain, the solution can be piped to a disposal facility 
71, such as a pH balance tank, where the solution can be further processed 
before being sent to drain. 
All of the valves and pumps in cleaning station 26 are controlled by a CIP 
station control 72. In turn, all of the station controls 72 for the 
various cleaning stations 26 may be linked to a main control 74, 
permitting easy control from a central location. 
In operation, the first procedure is the Soft Water Pre-Rinse. This step 
will remove any leftover product from the tank circuit 14. Soft water is 
permitted to enter the circuit 14 from the proper recirculating line 20 
while some of it is allowed to go straight to the wash/motive tank 30. 
Once the level in the wash/motive tank 30 reaches its minimum to operate 
the motive pump 58, the pump will start recirculating the water through 
the eductor 62. The vacuum created at the eductor 62 will start to pull 
the water out of the circuit 14, back to the wash/motive tank 30. As more 
water comes into the wash/motive tank 30 it will begin to fill towards its 
maximum level. When the maximum level is achieved, the divert valve 70 
will shift so that the returning water goes to the disposal facility 71. 
The water will be routed to the disposal facility 71 until the level in 
the wash/motive tank 30 comes down to a preset level, at which time the 
divert valve 70 will shift to bring the returning water back into the 
wash/motive tank. The divert valve 70 will shift back and forth 
controlling the level in the wash/motive tank 30 until the time programmed 
for the Pre-Rinse has elapsed. After the Pre-Rinse, the water will be shut 
off and the supply pump 44 stopped. Air will be blown through the circuit 
14 to push the water out. Once the water is evacuated from the circuit 14, 
the divert valve 70 will route the water to the disposal facility 71. No 
water will return to the wash/motive tank 30. The motive pump 58 will 
empty out the remaining water from the wash/motive tank 30. 
The purpose of the second step, Pre-Wash, is to wash the equipment that 
will be washing the circuit 14. This will eliminate the possibility of 
unwanted material to be introduced into the cleaning station 26 during the 
wash cycle. Pure water from the proper recirculating line 20 will enter 
the rinse tank 32 through a spray ball 76 thus cleansing the sidewalls. 
Wash solution from the proper recirculating line 20, through the 
wash/motive tank 30, will flow into the suction side of the supply pump 44 
before going through the heat exchanger 48. As it does so, the solution is 
routed through a spray ball 78 to clean the wash/motive tank 30. A motive 
outlet valve 80 will open and allow the solution to be pulled out by the 
motive pump 58. The divert valve 70 will be sending the solution on to the 
disposal facility 71 except for some pulses that will clean the valve and 
its return line to the wash/motive tank 30. The motive tank outlet valve 
42 that supplies the supply pump 44 will pulse a few times to clean out 
that area as well. After all of these components are cleaned, the excess 
solution will be pumped out to the disposal facility 71. 
Now the Wash-Charge step begins. This step will fill the wash/motive tank 
30, as well as the circuit 14 to be cleaned, with wash solution. The 
supply pump 44 may draw pure water from the rinse tank 32, in which case 
wash chemical is injected into the suction side of the pump from 
supplemental wash tank 47, creating wash solution inside the pump. The 
additional wash chemical can be supplied on the basis of time, or on the 
basis of a desired concentration of wash chemical in the solution, if a 
suitable sensor is provided. The wash solution thus created inside pump 44 
is then routed through the heat exchanger 48 and into the circuit 14, with 
a portion of the solution being routed to the wash/motive tank 30. This 
will continue until the minimum operating level is reached. Alternatively, 
the wash/motive tank 30 may be filled to its minimum operating level with 
wash solution from one of the large storage tanks 16. Once this minimum 
level is attained, the motive pump 58 will start. All the returning 
solution is sent to the wash/motive tank 30 causing it to fill. When it 
reaches its full level, then the Wash-Charge step is complete. 
With the wash/motive tank 30 and circuit 14 filled with wash solution, the 
Wash step begins. The solution is now drawn from the wash/motive tank 30 
by the supply pump 44. Simultaneously the solution is routed through the 
eductor 62. The wash solution is now being recirculated through the 
circuit 14 and wash/motive tank 30. The wash chemical may still be added 
to the solution from supplemental wash tank 47 until it is up to the 
recommended concentration for that circuit. The cleaning station 26 will 
continue to run until it has met its time and temperature requirements 
imposed by the control 72. Throughout this step, some wash solution will 
be sent to the wash/motive tank 30 through its spray ball 78 to wash it 
thoroughly. 
With the circuit 14 clean, the cleaning station 26 will now dump the used 
wash solution, in the Wash Dump step. The supply pump 44 pumping solution 
to the circuit 14 will stop, and an air blow procedure will begin. The 
motive pump 58 will continue to run, drawing the remaining solution out of 
the circuit 14. The returning solution is routed by the divert valve 70 to 
either the wash/motive tank 30 or the disposal facility 71 depending upon 
the level in the wash/motive tank 30. After the solution is out of the 
circuit 14, the divert valve 70 will route all flow to the disposal 
facility 71. This will continue until all the wash solution is removed 
from the cleaning station 26. 
The Pure Rinse step now follows. This step removes all the wash solution 
residue from the circuit 14. This step operates like the Pre-Rinse step 
except pure water is used instead of soft water. 
The Post-Rinse step begins by using air blow and the eductor 62 to empty 
out the circuit 14. Once this step is complete, the wash/motive tank 30 is 
given a thorough rinse with pure water. This step will finish by emptying 
the rinse tank 32 into the wash/motive tank 30 and then having the motive 
pump 58 empty out the wash/motive tank into the disposal facility 71. All 
components are rinsed and the cleaning station 26 is ready to begin 
another wash operation when needed. 
Accordingly the invention provides a system for cleaning a service tank 
installation with a minimum of floor space, a minimum of investment and a 
minimum of volume storage of cleaning solutions. 
While the apparatus hereinbefore described is effectively adapted to 
fulfill the aforesaid objects, it is to be understood that the invention 
is not intended to be limited to the specific preferred embodiment of 
cleaning system set forth above. Rather, it is to be taken as including 
all reasonable equivalents to the subject matter of the appended claims.