Patent Publication Number: US-2005121076-A1

Title: Vacuum transfer system and method for food grade product

Description:
RELATED APPLICATION  
      This application is a continuation of U.S. application Ser. No. 10/795,708, filed Mar. 8, 2004, which is a divisional of U.S. application Ser. No. 10/162,157, filed Jun. 3, 2002, which is a continuation of U.S. application Ser. No. 09/528,285, filed Mar. 17, 2000, which is a continuation-in-part of U.S. application Ser. No. 09/061,408, filed Apr. 16, 1998, now U.S. Pat. No. 6,058,949, issued May 9, 2000, which is a continuation-in-part application of U.S. application Ser. No. 08/632,558, filed Apr. 15, 1996, now U.S. Pat. No. 5,839,484, issued Nov. 24, 1998, which application claims the benefit of U.S. Provisional Application No. 60/001,846, filed Aug. 2, 1995, all of which are hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD  
      The present invention relates to the transfer of food grade product in and out of a vessel. More particularly, the transfer is effected by means of vacuum generated in the vessel.  
     BACKGROUND OF THE PRESENT INVENTION  
      Food grade product is presently transferred from one vessel to another vessel by means of mechanical pumps that typically have rotating impellers or the like that effect the pumping of the food grade product. Food grade product may include for example eggs, liquid ingredients for the making of ice cream, raw or processed milk, liquid feed for livestock, liquid ingredients for the making of cheese, and the like. Reference herein is with respect to the transfer of raw milk from a holding tank at the production site to a vehicle tank for the transfer of the raw milk to a processing plant. The vehicle may be either a truck or a trailer, as depicted, that is transported by a tractor. Those skilled in the art will recognize that the same principles as are described herein are applicable to other transfers of food grade product from a first vessel to a second vessel. For example, the transfer of raw milk from the truck or trailer-mounted tank to a tank in the processing plant may be effected by the present invention. Additionally, the transfer of food grade product from a first vessel in the processing plant to a second vessel in the processing plant may be effected by the present invention.  
      Bulk milk pick-up from the point of origin as we know it today, consists of a truck or trailer-mounted stainless steel insulated transport tank. This transport tank is at atmospheric pressure and is therefore not operated at a vacuum and not operated at a pressure greater than atmospheric pressure. In order to effect the transfer of the raw milk form the holding tank to the transport tank, both the holding tank and the transport tank are vented to the atmosphere during the transfer operations.  
      The amount of time spent transferring the raw milk or other food grade product is a major cost item. With respect to the transport of raw milk, this time dictates the number of drivers and transport trucks needed to service a specified route of customers. The size of dairies has been ever increasing and the distance between dairies on a route is also increasing. Dairy herds of more than two hundred animals are not considered big any more. This increase in size has required that the size of the holding tanks at the dairy be greatly increased. In the past, a five hundred gallon holding tank was considered adequate. The holding tank now may hold several thousand gallons of raw milk. The sheer size of the holding tanks has greatly increased the transfer times. During the transfer of the milk from the holding tank to the transport tank both the driver and the truck are idle, greatly increasing the cost of transporting the milk from the dairy top the processing plant.  
      The milk is presently pumped from the holding tank at the farm (or other site of pick-up) to the transport tank by several different types of mechanical food grade impeller pumps. Presently, the pump that will pump the greatest volume of milk is a hydraulic driven stainless steel gear pump that will pump 230 gallons per minute. The cost of this unit is approximately $15,000.00 installed. To transfer two thousand gallons of milk product using this pump takes in excess of eight minutes.  
      The problem to the purchaser of the aforementioned pump, aside from the cost, is a problem that is years old. Every time milk is forced through pump impellers, the bacteria count in the milk is multiplied, and the molecular structure of the raw milk product is broken down. The more agitation that is caused by the pump, the greater the increase in the bacteria level and the greater the molecular breakdown that results in the milk. The increase in the bacteria level can pose a serious health concern. Additionally, the membrane around the fat molecule is broken by the pump agitation, resulting in undesired acidity in the milk. The molecular breakdown results in a decrease in the amount of the milk that can be used as an ingredient in dairy products, such as ice cream and cheese. The non useable portion is disposed of as the whey that is a by product of making the dairy products and is useful primarily for animal feed. The animal feed is sold at substantially reduced cost as compared to products for human consumption that could otherwise have been produced, thereby reducing the potential return from a quantity of raw milk.  
      An additional health concern is the cleanliness of the pump used for the transfer of the food grade product from vessel to vessel. Recently, an incident of salmonella infection being passed on to the ultimate consumer as a result of the lack of cleanliness of the transport vessel has been reported. It is a requirement that the transfer pumps be disassembled at least daily and sanitized to preclude such a problem from occurring. Sanitizing the impellers of the pump is a difficult task. Only a small amount of the salmonella organism left in the impeller can taint a subsequent load of food grade product that is pumped into the vessel.  
      With the increased size of dairy holding tanks comes the need to increase the volume load of the transport tanks that are mounted on a single truck chassis. Many states have stringent regulations governing the gross weight of vehicles using the public roads. With the increased transport tank volume and the weight of milk product that is being transported, there is a need to keep the transport tank weight to a minimum in order to maximize the milk volume that may be legally transported.  
      It would be a decided advantage in the food products industry to be able to more rapidly transfer food grade product from one vessel to another and at the same time minimize the mechanical agitation of the food grade product that results from such transfer to minimize the bacteria count increase in the food grade product and to minimize the molecular structure breakdown that also results form the mechanical agitation. Further, it would be an advantage to have a transfer system for food grade product that was more easily sanitized.  
     SUMMARY OF THE INVENTION  
      Using the vacuum system of the present invention for transferring raw milk, the milk flows at a rate in excess of 2,000 gallons per minute through a six inch diameter conduit while transferring milk from the holding tank and loading the transport tank, thereby reducing the loading time at the pick-up point by a factor of almost ten as compared to the fastest current means. This is accomplished using existing piping from the holding tank to the transport tank. Such piping is typically six inch pipe. Coupled with the faster transfer time are a better load environment for the raw product, a significant lowering of the initial costs of the pumping system, and a reduction in clean-up and re-sanitizing time of the system as the raw product never touches any pumping mechanism, but is transferred solely through piping. No additional pump is necessary to effect the transfer of the food grade product. Additionally, from a health standpoint, there is no deleterious agitation of the food grade product heretofore associated with pumping by means of high speed impeller rotation. Further, the present invention includes a cleaning and sanitization system for cleaning and sanitizing both the tanks and the vacuum lines.  
      The present invention includes a cleaning apparatus for cleaning and sanitizing a tank, the tank for holding liquid food grade product, the liquid food grade product being transferred into and out of the tank by means of vacuum, the tank having a vacuum transfer system for transferring liquid food grade product includes apparatus for cyclically alternating a flow of cleaning fluid between the tank and the vacuum transfer system. The present invention is further, a method for cleaning and sanitizing a tank for holding liquid food grade product, the liquid food grade product being transferred into and out of the tank by means of vacuum, the tank having a vacuum transfer system for transferring liquid food grade product. The method includes the steps of: 
          (a) providing a cleaning fluid to a fluid inlet;     (b) cyclically alternating the flow of cleaning fluid between the tank and the vacuum transfer system; and     (c) venting the cleaning fluid from the tank and from vacuum transfer system;     whereby the tank and the vacuum transfer system are cleaned and sanitized during a single cleaning program having a selected series of rinse, cleaning and sanitizing cycles.       

    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a sectional side view of the vacuum transfer unit of the present invention as taken along lines  1 - 1  of  FIG. 2 ;  
       FIG. 2  is a side view of a vehicle with tandem transport tanks mounted thereon and a primary shutoff unit mounted in each of the transport tanks;  
       FIG. 3  is a side view of a tank vehicle with tandem transport tanks mounted thereon and a second embodiment of the vacuum transfer unit of the present invention mounted in each of the transport tanks with a portion of one tank broken away to reveal the vacuum unit mounted therein;  
       FIG. 4  is perspective view of the plumbing and valving of the rearmost vacuum transfer unit as depicted in  FIG. 3 ;  
       FIG. 5  is an elevational view of the vacuum transfer unit with portions thereof broken away;  
       FIG. 6  is an elevational view of the vacuum generation unit mounted on the tank vehicle;  
       FIG. 7  is an elevational view of the interior of the rear compartment of the tank vehicle;  
       FIG. 8  is a side view of a tank vehicle with tandem transport tanks mounted thereon and a vacuum transfer unit of the present invention mounted in each of the transport tanks with a portion of one tank broken away to reveal the vacuum unit mounted therein;  
       FIG. 9  is perspective view of the plumbing and valving of the rearmost vacuum transfer unit as depicted in  FIG. 8 ;  
       FIG. 10  is an elevational view of the interior of the rear compartment of the tank vehicle;  
       FIG. 10   a  is an enlarged elevational view of the control panel depicted in  FIG. 10 ;  
       FIG. 11  is a sectional view of a plunger-type valve as used in the present invention;  
       FIG. 12  is a sectional side view of another embodiment of the vacuum transfer unit of the present invention;  
       FIG. 12   a  is a detail sectional side view of the embodiment depicted in  FIG. 12 ; and  
       FIG. 13  is a sectional side view of the embodiment of the vacuum transfer unit of  FIG. 12  depicting operational movements in phantom. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      The vacuum transfer unit of a first embodiment of the present invention is shown generally at  10  in  FIGS. 1 and 2 . A tank vehicle  12  has a unitary transport tank  14  mounted thereon. In the depiction of  FIG. 2 , the transport tank  14  is divided into two separate tanks  14   a,    14   b.  A single tank  14  configuration could be used as well. Although the present invention is described with respect to a transport tank, the vacuum transfer unit  10  is useful for effecting transfer into and from any vessel.  
      The transport tank  14  is preferably constructed of 10 gauge stainless steel, (the same material and thickness as some non-vacuum tanks of today) and is reinforced with stainless steel hat channel rings and deep dish heads to keep the tank  14  from implosion during periods of high vacuum in the tank  14 . The cross section of the hat channels is substantially similar to the cross section of a hat having a crown and circular brim. Insulation is placed between the channels and a preferably stainless steel outer shell is affixed to the outer margin of the channels.  
      Each transport tank  14   a,    14   b  has a product inlet/outlet  16   a,    16   b  associated therewith. The product inlet/outlet  16   a,    16   b  is typically disposed at a low point in the transport tank  14   a,    14   b  so that the transport tank  14   a,    14   b  is filled from the bottom thereof and emptied from the bottom thereof. As depicted, a holding tank  18  is positioned adjacent to the tank vehicle  12 . The holding tank  18  has two outlets  20 . Each such outlet  20  is fluidly coupled to one of the product inlet/outlets  16   a,    16   b  by a flexible conduit  22 . The flexible conduit  22  is typically stored on the tank vehicle  12  and connected to the holding tank  18  at the product pickup site. The flexible conduit  22  may have a diameter between two and a half inches and six inches. The holding tank  18  has a inlet/vent  24  through which food product is transferred into the holding tank  18  and by which means the holding tank  18  is vented during removal of food product therefrom.  
      A vacuum generation unit  30  is mounted on the tank vehicle  12 . The vacuum generation unit  30  may be power take off (PTO) driven from the tractor (not shown) that is utilized to pull the tank vehicle  12 . The vacuum generation unit  30  is comprised of a pump  32 , a filter  34 , a lubricant trap  36 , and vacuum lines  38 . The pump  32  is preferably a vane type pump. The filter  34  isolates the pump  32  from any foreign material, including product, that may be passing through the vacuum lines  38 . A lubricant is typically injected into the pump to lubricate the interfaces between the vanes (not shown) and the inner surface (not shown) of the pump case of pump  32 . The lubricant trap  36  is downstream of the pump  32  and is utilized to entrain lubricant that is carried with the exhaust from the pump  32 . The lubricant so entrained may be then recycled back to the pump  32  to further lubricate the vanes thereof.  
      Referring to  FIG. 1 , a manway cover  50  is hinged at one side  51  and sealed at the perimeter thereof to the outer surface of the tank  14 . The manway cover  50  is generally circular and is contoured to conform to the surface of the outer shell of the tank  14 . The manway cover is preferably constructed of stainless steel.  
      A manway opening  52  is centrally disposed in the manway cover  50 . The manway opening  52  is preferably cylindrical in shape, having a lower margin that is shaped to conform to the contour of the manway cover  50 . The upper margin of the manway opening  52  has a sealing lip  54  defined thereon. The manway opening  52  is preferably a circular opening having a diameter of approximately two feet to make it possible for a person to enter the tank  14  through the manway opening  52 , if needed.  
      The vacuum transfer unit  10  of  FIG. 1  is depicted as being inserted from the top within the manway opening  52 . Note that in  FIG. 8 , the vacuum transfer unit  10  is depicted as being adjacent to the manway opening  52 . The vacuum transfer unit  10  is sealingly retained within the manway opening  52  by quick release clamp  56  affixed to the sealing lip  54 . The quick release clamp  56  is preferably a circular ring that encloses the sealing lip  54  and is held in sealing engagement therewith by an over center lock (not shown). The vacuum transfer unit  10  may be readily removed from the manway opening  52  in order to perform required cleaning and sanitizing by releasing the quick release clamp  56  and pulling the vacuum transfer unit  10  upward, clear of the manway opening  52 .  
      Vacuum transfer unit  10  is fully constructed of stainless steel material in order to meet the requirements for storing and transferring food grade product.  
      Vacuum transfer unit  10  has a low profile vacuum transfer dome  60  that forms the upper surface thereof. A float ball cage  62  depends from the vacuum transfer dome  60  and is attached thereto by float ball cage fastening clips  64 . The float ball cage  62  has a plurality of apertures  66  defined therein that permit the free flow of food product in and out of the float ball cage  62 , while retaining the stainless steel float ball  68  therein. The float ball  68  is generally spherical in shape and is sealed having a quantity of air trapped therein, such that the float ball  68  will float on top of the liquid food grade product that rises into the float ball cage  62 . When there is no liquid food grade product in the float ball cage  62 , the float ball  68  drops to the bottom of the float ball cage  62  and rests there.  
      A primary pipe  70  is disposed within the vacuum transfer dome  60  and provides a fluid passageway through vacuum transfer dome  60  from the float ball cage  62 . The lower margin of the primary pipe  70  has a generally circular beveled rubber float seal seat  72  disposed thereon. The float seal seat  72  is beveled inward, such that the lower most diameter of the beveled portion is greater than the uppermost, inner diameter of the beveled portion, as depicted in  FIG. 1 . The lowermost diameter of the float seal seat  72  is less than the diameter of the float ball  68 . The float seal seat  72  is designed to establish a fluidly sealing engagement with the outer surface of the float ball  68  when the float ball  68  has risen into the float seal seat  72  and is centered thereon. The upper margin of the primary pipe  70  is coupled to a stainless steel tee  74  by a stainless steel nut  76 .  
      A first outlet of tee  74  is coupled to a manually operated butterfly valve  80  by a stainless steel nut  76 . An external handle  82  is provided on the butterfly valve  80  to manually open and close the butterfly valve  80  as desired. A removable, disposable intake air filter  84  is attached to the butterfly valve  80 . The butterfly valve  80  connects the interior of the tank  14  with the outside atmosphere when the butterfly valve  80  is in the open configuration. The butterfly valve  80  could be replaced with another type of U.S.D.A. approved valve, such as a ball type, plunger type valve, or plug type valve.  
      The second branch of the tee  74  is coupled by a stainless steel nut  76  to a one way check valve  86 . The check valve  86  is biased in the closed configuration so that no fluid flow is possible through the check valve  86 . When in the open configuration, the check valve  86  permits the flow of fluid only from right to left as depicted by arrow  87  in  FIG. 1 . In order to open check valve  86 , a vacuum of less than ten inches of mercury, but preferably three to five inches of mercury must be applied at the left side of check valve  86 , as depicted in  FIG. 1 . The necessary vacuum to open the check valve  86  is applied to the left side of the check valve  86  by the vacuum generation unit  30  when the vacuum generation unit  30  is in operation. In all cases when the vacuum generation unit  30  is not in operation, the check valve  86  is biased in the closed configuration, isolating the vacuum line  38  from the tank  14 .  
      Check valve  86  is fluidly coupled by a stainless steel nut  76  to a backup butterfly valve  88 . Butterfly valve  88  is coupled to actuator  90 . Actuator  90  may be either electrically or pneumatically actuated. Actuation of actuator  90  is preferably synchronized with the activation of the vacuum generation unit  30 , such that the butterfly valve  88  is open when the vacuum generation unit  30  is operating and the butterfly valve  88  is closed when the vacuum generation unit  30  is not operating. The butterfly valve  88  is fluidly coupled to vacuum line  38  and thereby to the vacuum generation unit  30 .  
      Upon activation, the vacuum generation unit  30  draws a vacuum in the vacuum lines  38 . Such vacuum may selectively affect either or both of the vacuum transfer units  10 , as depicted in  FIG. 2 , depending on the configuration of the aforementioned valves of the two vacuum transfer units  10 .  
      The vacuum transfer unit of a second embodiment of the present invention is shown generally at  10  in  FIGS. 3-7 . Similar numerals depict similar components in the description of the second embodiment as in the description of the first embodiment of the vacuum transfer unit  10 .  
      A tank vehicle  12  has a unitary transport tank  14  mounted thereon. To facilitate the maintenance and cleaning of the vacuum transfer unit  10  and the tank  14 , a ladder  11  and a gangway  13  are provided to afford access thereto by an operator as needed. In the depiction of  FIG. 2 , the transport tank  14  is divided into two separate tanks  14   a,    14   b  by a wall  15 . A single tank  14  configuration could be used as well. Each transport tank  14   a,    14   b  has a product inlet/outlet  16   a,    16   b  disposed on the front wall  17  of the rear compartment  19  of the tank vehicle  12 , as depicted in  FIG. 7 . A flexible conduit  22  is stored in the rear compartment  19  for connecting to the holding tank  18 .  
      Referring to  FIG. 3 , a manway cover  50  is fluidly coupled to each tank  14   a,    14   b.  Each manway cover  50  is hinged at one side and sealed at the perimeter thereof to the outer surface of the tank  14 . The manway cover  50  is generally circular and is contoured to conform to the surface of the outer shell of the tank  14 . The manway cover  50  is preferably constructed of stainless steel and is designed to accommodate access to the tank  14  by an operator, primarily to clean the inside of the tank  14 .  
      A vacuum generation unit  30  is mounted on the tank vehicle  12  in a cabinet  31 . The vacuum generation unit  30  could as well be mounted on the tow vehicle and may be driven either by PTO (power takeoff from the tow vehicle), hydraulic actuation, or internal combustion engine. The vacuum generation unit  30  is self contained, in that it contains its own power generation capability and the vacuum generation unit  30  may be configured to either load product into the tank  14  or unload product from the tank  14 . This capability ensures that there is an on board capability to load and unload using the components of the present invention, without resort to an external source of power for either loading or unloading the tanks  14   a,    14   b.  This is an important feature so that the tanks  14   a,    14   b  can be loaded or unloaded at any facility without the need for specialized pumping capability at the facility adapted to be compatible with the vacuum transfer unit  10 .  
      The vacuum generation unit  30  is comprised of a pump  32 , a motor  100 , a secondary shutoff  102 , and vacuum lines  38 . The pump  32  is preferably a lobe type blower or a rotary vane type air compressor. The pump  32  is powered by a rotary drive shaft  103  coupled to the motor  100 . The pump  32  has an air line  104  that fluidly couples the pump  32  to the secondary shutoff  102 . A four way change over valve  106  is disposed between the air line  104  and the pump  32  and is mounted on the pump  32 . The four way change over valve  106  is utilized to selectively alter the fluid coupling from the pump  32  to the air line  104  such that a vacuum is drawn through the air line  104  or a fluid, preferably air, is forced under pressure through the air line  104 . The configuration of the four way change over valve  106  is selectable by an operator utilizing a two position valve handle (not shown). By this means, the pump  32  is used to either draw a negative pressure in the vacuum line  38  or to charge the vacuum line  38  under a positive pressure. Four way change over valve.  
      The motor  100  is preferably a gas internal combustion engine of approximately eighteen bhp. The motor  100  preferably has a battery and electric start capability that is selectable on an operator&#39;s panel  108 . The operator&#39;s panel  108  also has a throttle for control of the output of the motor  100  as desired. The motor  100  is designed to operate at an idle rpm. When at idle rpm, the motor  100  is disengaged from the pump  32 . The throttle can then be advanced to a greater rpm that activates a clutch engagement to the pump  32  and causes rotational driving of the pump  32  by the motor  100 .  
      The secondary shutoff  102  is a vessel that functions as a shutoff to isolate the pump  32  from any liquid that might be drawn from the primary shutoff  102  through the air line  104 . The primary shutoff function is accomplished with the vacuum transfer unit  10 . Accordingly, the secondary shutoff  102  has a float valve (not shown) disposed in the secondary shutoff  102  that is interposed between the vacuum line  38  and the air line  104  such that, when the liquid in the secondary shutoff  102  rises to a certain level in the secondary shutoff  102 , the float valve engages a seat and the flow of fluid to the pump  32  is interrupted. This prevents liquid from entering the pump  32 , which could result in damage to the pump  32 . A drain is disposed in the bottom of the secondary shutoff  102  to remove accumulated liquid. The secondary shutoff  102  has a valved drain  110  disposed in the bottom for the draining of liquid therefrom as desired.  
      Referring to  FIGS. 3-5 , the vacuum transfer unit  10  is depicted as being inserted from the top within a collar  112 . The collar  112  is affixed to the tank  14  as by welding. The vacuum transfer unit  10  is sealingly retained within the collar  112  by quick release clamp  56  removably affixed thereto. The quick release clamp  56  is preferably a circular ring that encloses a lip  54  that forms the upper margin of the collar  112  and is held in sealing engagement therewith by an over center lock (not shown). The vacuum transfer unit  10  may be readily removed from the manway opening  52  in order to perform required cleaning and sanitizing by releasing the quick release clamp  56  and pulling the vacuum transfer unit  10  upward, clear of the collar  112 .  
      The vacuum transfer unit  10  has a low profile vacuum transfer dome  60  that forms the upper surface thereof. A float ball cage  62  depends from the vacuum transfer dome  60 . The float ball cage  62  has a plurality of apertures  66  defined therein that permit the free flow of food product in and out of the float ball cage  62 , while retaining the stainless steel float ball  68  therein.  
      A primary pipe  70  is disposed within the vacuum transfer dome  60  and provides a fluid passageway through vacuum transfer dome  60  from the float ball cage  62 . The lower margin of the primary pipe  70  has a generally circular beveled rubber float seal seat  72  disposed thereon.  
      The upper margin of the primary pipe  70  is coupled by a stainless steel nut  76  to a butterfly valve  88 . The butterfly valve  88  is coupled to actuator  90 . Actuator  90  may be either electrically or pneumatically actuated and acts to open and close the butterfly valve  88 . Actuation of actuator  90  is preferably synchronized with the activation of the vacuum generation unit  30  and is controlled by means of communication lines  114  by manually operated switches  116   a,    116   b,  with the switch  116   a  being coupled to the actuator  90  on the vacuum transfer unit  10  in the tank  14   a  and the switch  116   b  being coupled to the actuator  90  on the vacuum transfer unit  10  in the tank  14   b.  The communication lines  114  are preferably either electric or pneumatic. The butterfly valve  88  coupled to the tee  74  by a nut  76 .  
      The tee  74  has a vent outlet  118  and a vacuum outlet  120 . The vent outlet  118  is connected to the vent line  122  by a nut  76 . The vent line  122  is coupled to a manually operated butterfly valve  80 , as depicted in  FIG. 7 . An external handle  82  is provided on the butterfly valve  80  to manually open and close the butterfly valve  80  as desired. The butterfly valve  80  is connected to a removable, disposable intake air filter  84  that is located in the rear compartment  19 . The butterfly valve  80  connects the interior of the tank  14  with the outside atmosphere when the butterfly valve  80  is in the open configuration.  
      The second branch of the tee  74  is coupled by a stainless steel nut  76  to a check valve  86 . The check valve  86  is biased in the closed configuration so that no fluid flow is possible through the check valve  86 . When in the open configuration, the check valve  86  permits the flow of fluid only from right to left as depicted by arrow  87  in  FIG. 1 . In order to open check valve  86 , a vacuum of less than ten inches of mercury, but preferably three to five inches of mercury must be applied at the left side of check valve  86 . The necessary vacuum to open the check valve  86  is applied to the left side of the check valve  86  by the vacuum generation unit  30  when the vacuum generation unit  30  is in operation.  
      Cleaning lines  130  are fixedly coupled to the tank  14 . An inlet  132  is depicted in  FIG. 4 . The inlet  132  provides a coupling to an exterior source of cleaning solution that may be introduced under pressure to the tank  14 . A valve  136  that is manually operated by handle  136  is disposed in the cleaning lines  130  so that the cleaning solution may be introduced to either or both of the tanks  14   a,    14   b,  as desired. A spray-ball type nozzle  138  is coupled to the cleaning lines  130  and is disposed within the tank  14  for dispensing the cleaning solution in order to flush the tank  14 .  
      Upon activation, the vacuum generation unit  30  draws a vacuum in the vacuum lines  38 . Such vacuum may selectively affect either or both of the vacuum transfer units  10  as depicted in  FIGS. 2 and 3  by selectively configuring appropriate valves in the vacuum lines  38 .  
      There are essentially three operating conditions for the present invention. Referring to the embodiment of  FIGS. 1 and 2 , the first such operating condition is transferring food product from the holding tank  18  into the transport tank  14   a,    14   b.  To effect such transfer by means of vacuum, (a) the tank into which the food grade product is to be transferred, transport tank  14   a,    14   b  in the present example, must be isolated from the atmosphere, (b) the two tanks must be fluidly connected, as by conduit  22  in the present example, and (c) the tank being transferred from, here holding tank  18 , must be vented to the atmosphere as at inlet/vent  24 . This creates a fluid flow path from the vacuum generation unit  30  through the tanks  14   a,    14   b,  and holding tank  18  to the atmosphere at inlet/vent  24  with the food grade product disposed between the source of the vacuum and the atmosphere. Generation of the vacuum by vacuum generation unit  30  will draw the food grade product toward the source of the vacuum and displace the food grade product in the holding tank  18  with air drawn in through the inlet/vent  24 .  
      In order to establish the requisite fluid flow path as indicated above to effect such transfer, the vacuum transfer unit  10  is configured with the manually operated butterfly valve  80  maintained in its closed position. This isolates the tank  14  from the atmosphere. The vacuum generation unit  30  is activated and at the same time a signal is sent to valve actuator  90  to open the butterfly valve  88 . When the butterfly valve  88  is in the open configuration, the check valve  86  is in flow communication with the vacuum generation unit  30  and vacuum generated by the vacuum generation unit  30  acts upon the check valve  88 . At such time as the vacuum generation unit  30  applies a three to five inch of mercury vacuum to the check valve  86 , check valve  86  opens.  
      With respect to the embodiment of  FIGS. 3-7 , the manually operated butterfly valve  80 , which is located in the rear compartment  19 , is maintained in its closed position. The appropriate switch  116   a,    116   b,  also located in the rear compartment  19 , is selected to actuate valve actuator  90  to open the butterfly valve  88  for the desired tank  14   a  or  14   b.  Prior to energizing the pump  32 , the four way change over valve  106  must be in the position such that the pump  32  is drawing a vacuum in the vacuum lines  38 .  
      At this point a vacuum is drawn in the transport tank  14   a,    14   b.  The vacuum is approximately 22-25 inches Hg. The vacuum is transmitted to the transport tank  14   a,    14   b  via primary pipe  70  and the plurality of apertures  66  defined in the float ball cage  62 . The vacuum does not affect the float ball  68  and the float ball  68  remains disposed on the bottom of the float ball cage  62 .  
      As the air in the transport tank  14   a,    14   b  is substantially exhausted by the vacuum generation unit  30 , the vacuum acts through the conduit  22  on the food grade product that is stored in the holding tank  18 . This vacuum draws the food product from the holding tank  18  through the flexible conduit  22  and into the transport tank  14   a,    14   b  at a very high rate of flow without the agitation caused by a pump impeller. As the food grade product is drawn from the holding tank  18 , air is drawn into the holding tank  18  through the open inlet/vent  24 .  
      The holding tank  18  may have a lesser capacity than the tank  14 . In this instance, the holding tank  18  will be emptied prior to fully filling the transport tank  14   a,    14   b.  The operator then observes the emptying of the holding tank  18  and shuts off the vacuum generation unit  30 . At the same time as deactivation of the vacuum generation unit  30 , a signal is sent to the valve actuator  90  closing the butterfly valve  88 . Additionally, removal of the vacuum from left side of the check valve  86  that is the result of deactivating the vacuum generation unit  30  causes the check valve  86  to close, sealing the vacuum transfer unit  10 .  
      In the instance in which the food grade product that is transferred to the transport tank  14   a,    14   b  causes he transport tank  14   a,    14   b  to become filled prior to completely transferring the food grade product from the holding tank  18 , the stainless steel float ball  68  rises as the food grade product flows into the float ball cage  62  and sealingly engages the float seat  72 . In such condition, the vacuum generation unit  30  is incapable of applying a vacuum to the transport tank  14   a,    14   b.  The operator then deactivates the vacuum generation unit  30 . The butterfly valve  88  and check valve  86  are then closed as previously indicated.  
      The second operating condition is in transport of food product. In this condition, the manually (or pneumatically) operated butterfly valve  80  is maintained in its closed position. The check valve  86  is closed due to the fact that no vacuum is being applied thereto by the vacuum generation unit  30 . If the transport tank  14   a,    14   b  is overly full, the float ball  68  will also in contact with the float seat  72 , preventing the surge of foam or food grade product into the primary shut off unit  10 . In practice, it is rare that the transport tank  14   a,    14   b  will be so full as to cause this condition and the float ball  68  is then floating free of float seat  72 .  
      The third operating condition is emptying the transport tank  14   a,    14   b.  In this operating condition, as depicted in the embodiment of  FIGS. 1 and 2 , the operator must ascend to the top of the tank  14   a,    14   b  and manually open the butterfly valve  80  by actuation of the handle  81  to vent the transport tank  14   a,    14   b.  Alternately, the a remote pneumatic switch may used to operate the butterfly valve  80 . This same action is accomplished in the rear compartment  19  in the embodiment of  FIGS. 3-7 . The check valve  86  and butterfly valve  88  are maintained in their closed positions. A conduit similar to conduit  22  is connected to the product inlet/outlet  16   a,    16   b  and pumps in the plant that is receiving the food product are activated to empty the transport tank  14   a,    14   b.  The plant may also be equipped with a vacuum transfer apparatus in accordance with the present invention. In such case, a vacuum generation unit similar to vacuum generation unit  30  and a vacuum transfer unit  10  are operably coupled to a receiving tank within the processing plant and removal of the food grade product from the transport tank  14   a,    14   b  is accomplished in a manner similar to the manner described above for transferring the food grade product from the holding tank  18  to the transport tank  14   a,    14   b.    
      With respect to the embodiment of  FIGS. 3-7 , the tanks  14   a,    14   b  may be emptied by utilizing the vacuum generation unit  30 . In this case, the four way change over valve  106  must be in the position such that the pump  32  is pressurizing the vacuum lines  38 . The preferred vacuum generation unit  30  is capable of imposing a pressure of approximately ten lb/sq in on the product in the tank  14   a,    14   b.  This pressure is conveyed by means of vacuum lines  38  through the vacuum transfer unit  10 . The pressure forces the product out of the product inlet/outlet  16   a,    16   b.  Alternatively, in the instance where the plant to which the product is being transferred has a pressurization capability, the plant pressurization unit may be connected to the vent line  122  to pressurize the product in the tank  14 . This is accomplished by removing the filter  84  and connecting a conduit from the plant pressurization unit to the butterfly valve  80 . The butterfly valve  80  is then opened. The butterfly valve  88  must also be opened by activating the actuator  90  by means of the switch  116   a,    116   b.  In this configuration, the one way check valve  86  prevents the pressure from pressurizing the vacuum lines  38 .  
      As previously indicated, the cleanliness and sterility of the tanks  14  and associated plumbing is a paramount need. Further, there is a need to perform the necessary cleaning in as timely a manner as possible. Typically, a facility that receives the transported food grade product has one or more cleaning bays. At the end of each work day after the tanks  14  have been unloaded for the last time, the tank vehicle  12  is positioned in the cleaning bay for cleaning of the tank  14 .  
      The cleaning is done in a manner prescribed by governmental bodies, primarily the U.S. Department of Agriculture. A typical cleaning and sanitizing cycle may extend for as much as 25 minutes. The cleaning program typically proceeds through a rinse cycle, a wash cycle, a rinse cycle, a wash cycle, a rinse cycle, and a sanitizing cycle. The cleaning bay has a cleaning unit that includes a hose hook-up for the tank  14 . The cleaning unit operates at a certain pressure and volume and cycles through the cleaning program, changing the liquid provided to the tank  14  depending on the particular cycle that the cleaning program is presently operating in.  
      In addition to cleaning and sanitizing of the tanks  14 , the vacuum transfer unit  10  of the present invention includes vacuum lines that must also be cleaned and sanitized since the vacuum lines and the vacuum transfer unit  10  are exposed to the food grade product during transfer operations. In order to efficiently clean and sanitize both the tanks  14 , the vacuum transfer units  10 , and the vacuum lines associated with the vacuum transfer unit  10 , it is desirable to clean the entire system, tanks  14 , vacuum transfer units  10 , and vacuum lines, during a single cleaning and sanitizing operation. The cleaning system  200  of the present invention provides this single operation cleansing both the tanks  14  and the associated vacuum lines.  
      The cleaning system  200  is shown generally in  FIGS. 8-11 . The cleaning system  200  is an improved version of the previously described cleaning apparatus. Like numerals indicate like components in the cleaning system  200  and in the previously described cleaning apparatus. Referring to  FIGS. 8 and 9 , the detail depicted in  FIG. 9  with reference to the rear tank  14   b  is substantially duplicated with reference to the forward tank  14   a.  The vacuum line  122  and the cleaning line  130  both extend to the rear of the tank  14   b  and are plumbed into the rear compartment  19 .  
      A control panel  206  disposed in the rear compartment  19  controls the operation of cleaning system  200 . The control panel  206  has two switches  202   a  and  202   b  mounted thereon. In a preferred embodiment, the switches  202   a,    202   b  are three-position switches, being selectable between a load position, an off position, and a clean position, as depicted in  FIG. 10   a.  The switches  202   a,    202   b  are communicatively coupled to a timer  212 . The timer  212  is communicatively coupled to the two valves  88  (for tanks  14   a  and  14   b ) by means of communication lines  114   a  and  114   b.  Additionally, the switches  202   a,    202   b  are respectively coupled to the valves  136  (for tanks  14   a  and  14   b ) by means of communication lines  204   a  and  204   b.  The timer  212  is additionally communicatively coupled to a clean valve  214  by means of a cleaning communication line  208  and to a vacuum valve  216  by means of a vacuum communication line  210 .  
      Referring to  FIG. 10 , the cleaning line  130  is fluidly coupled to the clean valve  214 . The vacuum line  122  is fluidly coupled to the vacuum valve  216 . A T-connector  218  fluidly couples the clean valve  214  and the vacuum valve  216 . A filter  222  is disposed on a fitting  220  of the T-connector  218 . It should be noted that during cleaning operations, the filter  222  is removed to expose the fitting  220  for connection to the line from the cleaning system in the cleaning bay.  
      In a preferred embodiment, the valves  88 ,  134 ,  214 , and  216  are all plunger type valves as depicted at  224  in  FIG. 11 . Preferably, the plunger valve  224  is operated pneumatically through a pneumatic inlet  226 . Air pressure applied through the pneumatic inlet  226  acts to unseat the plunger  228  to move the plunger  228  to its open disposition as depicted in  FIG. 11 . In the open disposition of the plunger  228 , the fluid inlet  230  is fluidly coupled to the fluid outlet  232 .  
      When pneumatic pressure is removed from the pneumatic inlet  226 , the return spring  234  acts on the plunger shaft  236  to return the plunger  228  to a sealed engagement with the seat  236 . This action fluidly uncouples the fluid inlet  230  from the fluid outlet  232 .  
      An advantage of the plunger valve  224  as depicted in  FIG. 11  is that during cleaning operations, the wetted portions of the plunger valve  224  have been determined to be adequately cleaned and sanitized without removal of any component of the plunger valve  224 . Plunger valves of this type are available from Waukesha Cherry-Burrel, Corp., Delevan, Wis.  
      In a cleaning operation, the filter  220  is removed from the fitting  220 . A suitable hose is connected to the fitting  220  from the cleaning system in the cleaning bay. Additionally, drain hoses are coupled to the product inlet/outlet  202   a,    202   b  of the tanks  14   a  and  14   b,  respectively. Further, a drain hose is connected to the drain  110  of the secondary shutoff  102 . The switches  202   a  and  202   b  are rotated to the clean position. This activates the timer  212 .  
      The timer  212  synchronizes the opening and closing of the valves  88 ,  134 ,  214 , and  216 . In a preferred embodiment, the timer  212  alters the configuration of the aforementioned four valves every ten seconds during a cleaning operation. The duration of time between the configuration changes may be altered to match the duration of the various cycles of the cleaning operation as determined by the cleaning system of the cleaning bay. A cleaning system that has relatively high fluid flow rates and fluid pressure typically spends less time in a cycle than a cleaning system that has relatively low fluid flow rates and fluid pressure. The timer  212  may be programmed to vary the configuration switching time to accommodate the cleaning program of the specific cleaning system. During a rinse, wash, or sanitize cycle of the cleaning operation, the configuration of the aforementioned four valves is changed at least once and preferably two or more times during each cycle. The configuration changes of the four valves may vary between once each five seconds and once each five minutes.  
      In a first configuration, valves  216  and  88  are opened and valves  214  and  134  are closed. In this configuration, cleaning fluid entering fitting  220  is directed through vacuum line  122  to clean the vacuum transfer unit  10 . The cleaning fluid is additionally forced through line  38  to the secondary shutoff  102 . The fluid cleans the secondary shutoff  102  and then is expelled through drain  110 .  
      In the second configuration, valves  214  and  134  are opened and valves  216  and  88  are closed. In this configuration, cleaning fluid is forced through cleaning line  130  to the spray ball  138  in order to purge the tank  14   a,    14   b,  respectively. Cleaning fluid entering the tanks  14   a,    14   b  is then discharged from the product inlet/outlet  202   a,    202   b.  In this manner, the tanks  14   a,    14   b  and associated vacuum transfer units  10 , as well as vacuum lines  122 , are all cleaned during a single cleaning operation. It should be noted that the sequencing the valves  88 ,  134 ,  214 , and  216  between the open and closed configurations occurs substantially simultaneously under control of the timer  212 .  
      A further preferred embodiment of the vacuum transfer unit  10  is depicted in  FIGS. 12, 12   a,  and  13 . The vacuum transfer unit  10  includes a primary assembly  200  and a ball cage assembly  202 .  
      The primary assembly  200  includes a rim  204  that is sealingly engaged with an aperture defined in the tank  14 . The rim has a central aperture  206  defined therein. A domed lid  208  is suspended by engagement with the rim  204  in the central aperture  206 .  
      The domed lid  208  preferably has two pairs of depending retainers  210 .  
      Referring to  FIG. 12   a,  a pair of depending retainers  210  is depicted fixedly coupled to and depending from the domed lid  208 . Each of the depending retainers  210  bends inward to be more closely disposed to the ball cage assembly  202 . The depending retainers  210  have a retainer aperture  212  defined therein. A retaining rod  214  is passed through the retainer apertures of each of the depending retainers  210  defining a pair of depending retainers  210 . The retaining rod  214  may have a head  216  at one end and a removable clip  218  at the other end.  
      Referring again to  FIG. 12 , the domed lid  208  has an upward directed fluid coupling. The fluid coupling  220  may be releasably coupled to vacuum and cleaning plumbing as depicted in  FIGS. 1, 4 , and  5 . a fluid pipe  222  depends from the fluid coupling  220 . A circumferential seal  224  is imposed over the distal end of the fluid pipe  222 . A fluid opening  224  is defined in the distal end of the fluid pipe  222  and seal  224  combination.  
      The ball cage assembly includes two components: cage  226  and ball  228 . The cage  226  has a conical continuous depending wall  230 . There are no apertures defined in the wall  230  between the upper margin  232  and the ball opening  236  with the exception of the relatively small slits  238  as will be described below. The upper margin  232  of the conical wall  230  is spaced apart from the domed lid  208  such that fluid may readily pass over the upper margin  232  of the conical wall  230 .  
      The conical wall  230  has an inward taper  234  defined proximate the lower margin  235  of the conical wall  230 . The lower margin  235  defines a generally circular ball opening  236 . It should be noted that the diameter of the ball opening  236  is substantially less than the diameter of the ball  228  in order to retain the ball  228  within the cage  226 .  
      Two pair of relatively small slits  238  are defined through the conical wall  230 . The conical wall  230  is removably suspended from the domed lid  208 . This is accomplished by passing the retaining rod  214  through a first slit  238  through the inside of the conical wall  230  and out the second slit  238  to engage the depending retainer  210 .  
      The ball  228  may be conveniently be made in two halves, the upper spherical portion  240  being formed in a very close tolerance hemispherical shape to ensure a sealing engagement with the seal  224 . The lower portion of the ball  228  need not be made with such close tolerances. A weight  242  fixedly adhered to the lower portion of the ball  228  ensures that the spherical portion  240  of the ball  228  is always upwardly disposed.  
       FIG. 13  depicts the vacuum transfer unit  10  of the present invention in two operational modes. The first operational mode is during cleaning of the vacuum transfer unit  10  and the tank  14 . In this mode, cleaning solution and rinse are alternately pumped into the fluid coupling  220  and down through the fluid pipe  222  exiting the fluid opening  225 . The ball  228  drops downward within the cage  226  and is engaged in a generally sealing engagement with the ball opening  236 . In such engagement, cleaning solution or rinse flowing into the cage  226  is prevented from flowing out the ball opening  236  and builds up within the cage  226  to cleanse/rinse both the cage  226  and the underside surfaces of the domed lid  208 . The cleaning solution or rinse flows over the upper margin  232  of the conical wall  230  and into the tank  14  after thoroughly cleansing the wetted surfaces of the vacuum transfer unit  10 .  
      The second operation depicted in  FIG. 13  is during suction filling of the tank  14 . During such operations, a vacuum is imposed on the fluid coupling  220 . The vacuum on the tank  14  is drawn primarily via the space defined between the upper margin  232  of the conical wall  230  and the underside of the domed lid  208 , since the ball  228  is sealed against the ball opening  236 . An advantage of such design is that the weight  242  holds the ball  228  into a stable engagement with the ball opening  236 , thereby preventing chattering of the ball  228  against the conical wall  230  during the application of suction to the fluid coupling  220 .  
      As the product  244  rises in the tank  214 , the ball  228  is floated upward toward the seal  224 . When the product  244  rises to the level indicated in phantom in  FIG. 13  (the level depicted also in  FIG. 12 ), the spherical portion  240  of the ball  228  comes into sealing engagement with the seal  224 , sealing off the fluid opening  225 . An advantage of the end embodiment of  FIGS. 12-13  is that by having a continuous conical wall  230  is that any foam  246  that is on top of the product  240  is kept outside of the cage  226  and is not drawn upward by the vacuum through the fluid pipe  222  prior to the sealing engagement of the ball  228  with the seal  224 . It is highly advantageous in operation, to prevent any of the product  244  including foam  246  from passing through the vacuum plumbing where it may enter the pump drawing the vacuum.