Abstract:
A hot fill apparatus for use in the testing of hollow thermoplastic containers, the apparatus having a reverse osmosis filter system, a heater system and a fill head system. The reverse osmosis filter system removes chlorine and other particulates and contaminants from the water prior to the water entering the heater system. The heater system is designed to maintain strict temperature control of the water while maintaining a steady flow rate and pressure. The fill head system includes a manually operated spigot and an automatically operated fill head, the operations of which are mutually exclusive.

Description:
This application claims the benefit of U.S. Provisional Appication(s) No.: 60/147,995 filed on Aug. 10, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a hot fill apparatus and process for use in the manufacture of hollow blow molded containers constructed from a thermoplastic, such as a thermoplastic polyester or a biaxially oriented polyethylene terephthalate resin. Hollow blow molded thermoplastics are commonly used as containers for food and beverages. Such containers, particularly containers constructed of a biaxially oriented polyethylene terephthalate resin (“PET”), must be periodically tested during manufacture for structural resiliency under hot fill and cold fill applications. For instance, in manufacturing operations producing between 5,000 and 50,000 containers per hour, batches of the containers are regularly tested, in many cases on an hourly basis, to ensure continued quality of manufacture. These requirements are met by a hot fill apparatus which fills the container with hot water, commonly maintained at a temperature close to boiling and then quick cools the container. The hot fill and quick cool application of water to a container provides a quality check of the resiliency of the container shape against expansion, contraction and undesirable deformation. 
     Flow through hot fill machines are designed to maintain a specified pressure and flow rate of water through the apparatus regardless of whether the apparatus is in use. Maintenance of flow rate and pressure are necessary to maintain strict regulation of water temperature within the hot fill apparatus. Some prior art hot fill machines will use at least one “instant heat” water heater and commonly use up to three such water heaters linked in combination to maintain strict temperature control of the water. Such water heaters demand a constant flow rate and a constant pressure of water passing through the heaters to prevent damage to the heaters. Commonly, the pressure is maintained at or above a required minimum of 20 psi and the flow rates are maintained at or above a required minimum of 1.5 gallons per minute with an optimum flow rate being 3 gallons per minute. Thus, some prior art flow-through hot fill machines have a water flow control system which provides a desired input volume into the heating loop and maintains a desired output volume from the heating loop. When the machine is not in use, the water output from the heating loop commonly enters a bypass flow to a drain. 
     Hot fill machines commonly have a number of faults which make them unreliable and many times undesirable. 
     Hot fill machines commonly work with conditioned water, water obtained from municipal water sources, and well water. Most water, even softened water, contains undesirable amounts of chemicals, minerals and other contaminants such that scale and chemical or mineral deposits will be formed, over time, on the heaters. An accumulation of scale or deposits on the heaters cause the heater mechanisms to become inefficient, resulting in premature failure and overloading of the heaters, thereby shutting down the machine and forcing costly repairs. Thus, it is desirable to provide a hot fill machine and process that can treat the input water prior to heating to remove undesirable chemicals, minerals and other contaminants. 
     Many common prior art hot fill machines use a spring activated valve or nozzle which is pressed upon the thermoplastic container mouth to open the valve and cause the hot fill water to flow into the container. Such spring activated valves sometimes put too much pressure on the container and have been known to deform or crush the container. A hot fill machine having a redesigned valve member is desired. 
     SUMMARY OF THE INVENTION 
     The present invention provides solutions to the above problems in the following manner. Water intended to flow to the heaters is first received from the water source and treated by a reverse osmosis filtration system. The reverse osmosis filtration system serves to trap and eliminate most all minerals and chemicals which are known to deposit upon and contaminate the heaters, thereby eliminating many known causes of heater inefficiency and premature failure. The reverse osmosis system as incorporated in this hot fill machine ideally uses a carbon canister having 2 parts per million chlorine removal capability with a backflush provision. The flow rate into the reverse osmosis system is designed to provide the desirable input flow into the heaters, thereby creating the desirable output flow from the heaters. The reverse osmosis system by nature of its operation creates an output flow rate which is less than the input flow rate, commonly by a ratio of three to one. For instance, one embodiment of the invention will input water at 6 gallons per minute into the reverse osmosis system to receive an output of clean uncontaminated water at 2 gallons per minute which flows to the heater mechanisms. The 4 gallons per minute flow differential is either recirculated back to the inlet side of the water pump or, if the water is heavily contaminated, is dumped to the drain. The reverse osmosis system, as incorporated into this invention, is designed with an automatic backwash for the carbon tanks which is operational when it is sensed within the hot fill apparatus that the system is in idle and not being used for hot fill applications. 
     The fill mechanism of the hot fill apparatus of this invention is normally provided with, for alternative usage, an on/off spigot and an automatic fill head. The spigot is used for any purpose and is not controlled by the height, volume and top load force variables which are used to control the fill head. The automatic fill head includes a rodless air cylinder with an adjustable slide through which an operator can dial in the bottle height and top load which is desired to simulate the load that a container will experience when filled with end product. Commonly, the top load is greater than 3 pounds, but less than 14 pounds. After the operator has established the bottle size and top load, the fill head is automatically activated to hot fill the container. Sensors act to sense the fill level and discontinue the fill and return the fill head to its original start position. Alternatively, controls are provided through which an operator can adjust the amount of fluid flowing into a container, thereby causing the fill head to automatically shut off. An override switch is also provided which can deactivate or activate the fill nozzle solenoid at any point in the cycle. 
     The hot fill machine is designed to have continuous flow and is provided with a normally open solenoid valve that directs flow to the drain and automatically closes when either the spigot or the fill head is activated. The spigot and fill head cannot be activated at the same time, thereby assisting and maintaining the controlled flow and temperature required for the proper operation of the hot fill apparatus. 
     These inventive aspects of the hot fill apparatus and process are achieved by the apparatus described and disclosed in the following drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevation view of the hot fill apparatus of the present invention. 
     FIG. 2 is a right side elevation view of the hot fill apparatus of the present invention. 
     FIG. 3 is a top view of the hot fill apparatus of the present invention. 
     FIG. 4 is a front detail view of the automatic fill nozzle of the hot fill apparatus of the present invention. 
     FIG. 5 is a side detail view of the automatic fill nozzle of the hot fill apparatus of the present invention. 
     FIGS. 6A and 6B are a piping and pneumatic flow diagram for the hot fill apparatus of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1-3, the general structure of the hot fill apparatus of the present invention is shown. The preferred embodiment includes a cabinet casing  10  which houses a reverse osmosis filter system, heating system and the variety of control valves, gauges and inert tubing. While the description of the preferred embodiment of the invention describes a single unit housing the reverse osmosis system and heaters, it is easily envisioned that the reverse osmosis system can be physically separated from the heater and nozzle apparatus, thereby reducing the size of the hot fill machine and possibly allowing for more than one hot fill machine to be operated with a single reverse osmosis system. 
     FIG. 1 is a front view of the hot fill apparatus, wherein the cabinet  10  includes a pair of doors  101 ,  102 , which when opened, provide access to the interior of the hot fill apparatus. The cabinet  10  rests upon a plurality of rollers  103  which allow the cabinet to be rolled around the work space and locked into position at a given location. A programmable logic controller or computer (PLC)  104  is mounted on the side of the cabinet  10 . The PLC  104  controls the operation of the hot fill apparatus, including all systems contained therein. The exterior casing of the PLC is provided with an on/off switch  105  which activates and deactivates the entire hot fill apparatus. 
     The cabinet  10  includes a shelf and drain structure  106  which provides support for any thermoplastic bottles or containers which are placed under the spigot  47  or fill head  44 . Structural locator members  107  are provided to retain a bottle or container in position with regard to the automated fill head  44 . The area surrounding the spigot  47  and the area surrounding the automated fill head  44  are each enclosed by splash guards  108 . A manual on/off PLC override switch  109  is provided for the automatic fill head  44  and on/off switches  110  are also provided for the activation and deactivation of the spigot  47 . A flow meter  25  visible on the front of cabinet  10  of the hot fill apparatus provides a continuous readout of the water exiting the water entering the reverse osmosis system. 
     The fluid and water circuits of the preferred embodiment of the present invention will be described specifically with reference to FIGS. 6A and 6B. The various elements which comprise the reverse osmosis system, heating system and air pressure system are arranged within the cabinet casing  10 . 
     Referring to FIGS. 6A and 6B, water received from an outside source (not shown) enters the apparatus through ball valve  11  which introduces the water into the reverse osmosis system which includes a charcoal filter  14  for chlorine removal, a large particle filter  18  for large particulate removal and, preferably, two reverse osmosis filters  26 . The ball valve  11  is designed to close when the interior water pressure within the hot fill apparatus is greater than the water pressure of the water flow from the outside source. The charcoal filter  14 , for chlorine removal, includes a timer  13  which is engaged with the charcoal filter  14  to provide for timed backflushing of the charcoal filter  14  through backflush ball valve  12  to provide regular cleansing of the membrane materials within the charcoal filter  14 . Timer  13  is linked to the programmable logic controller (PLC)  104  which controls the entire hot fill apparatus. As the chlorine-free water exits the chlorine filter  14 , a flow switch  16 , also receiving controlling input from the PLC  104 , controls the flow of water from the charcoal filter  14  through incoming ball valve  15  and inlet pressure gauge  17 . The incoming chlorine-free water then passes through a large particle filter  18  containing a filter element  19  intended to remove particles having a size of 10 microns or greater. An outlet pressure gauge  20  is provided to sense the differential between the inlet pressure to the filter  18  and the outlet pressure, thereby determining the need for filter replacement. If the outlet pressure gauge senses a high differential, it signals the PLC and the operator is notified to replace the filter element  19 . The filtered chlorine-free water then passes through a solenoid operated valve  21  which is the automatic water feed for the reverse osmosis canisters  26 . The solenoid operated valve  21  is controlled by the PLC  104  to provide a steady flow of water into the reverse osmosis system. A pump  24  operated by motor  23  is used to increase the pressure of the inlet water and the pressure of the inlet water is monitored by high pressure gauge  25 , all of which are responsive to the PLC  104 . The reverse osmosis canisters  26  will output water into the heaters at desired flow and pressure rates and the PLC  104  controls the flow and pressure rates of the input water into the reverse osmosis canisters  26  such that the water output to the heater system is maintained at a predetermined steady pressure and flow rate. For instance, the pump  24  is activated by the PLC  104  in one embodiment to input water at 6 gallons per minute into the reverse osmosis canisters  26 , thereby receiving an output of clean uncontaminated water at 2 gallons per minute which flows to the heater system. The 4 gallons per minute differential of water flow is either recirculated back to the inlet side of the water pump  24  or, if the water is heavily contaminated, is dumped to the drain. 
     Each reverse osmosis canister  26  contains a reverse osmosis membrane filter  27 . The reverse osmosis filters  27  will remove and eliminate most all minerals and chemicals within the water supply. As the water is filtered through the first filter  27 A, cleansed water will exit the first filter  27 A through clean water conduit  22 . Water which is still contaminated will exit the first filter  27 A and enter the second filter  27 B through concentrate conduit  33 . After passing through the second reverse osmosis filter  27 B, clean water will again exit through clean water conduit  22  for transportation to the heater system and concentrate containing contaminated water will exit the second reverse osmosis filter  27 B for either recycling back to the feed water lines leading to the reverse osmosis pump  24 , or to be dumped to the drain. The contaminated concentrate will flow to the concentrate control regulator  28  which is preset by the PLC  104  to regulate the back pressure to the reverse osmosis filters  27 A,  27 B, and thereby control the pressure output from the reverse osmosis filters  27 A,  27 B to the heater system. A metering valve  30 , also controlled by the PLC  104 , works in combination with the concentrate control regulator  28  to determine whether the contaminated concentrate exiting the reverse osmosis filter  27 B should be recycled for reuse or dumped to the drain. Flow meter  29  monitors the concentrate flow to the drain and flow meter  31  monitors the recycle flow. 
     As the clean water exits the reverse osmosis filters  27 A,  27 B through the clean water conduit  22 , the clean water flows through the pressure switch  32  which controls the infeed pressure for the heater system and presets the water pressure to a predetermined level, preferably 20 psi. The clean infeed water, now flowing at the predetermined pressure, enters the flow meters  34 ,  35  which control the flow rate of the clean water and are manually adjustable to provide a desired flow rate of clean water into the heater system, preferably 2 gallons per minute. As the clean water flows to the heater system, it passes through a water hammer arrester  36  which protects the heater system from any surges in water pressure or flow rate. The clean water then passes through a final pressure gauge  38  which monitors the pressure feeding to the water heater system. 
     The heater system of the preferred embodiment is composed of a slave heater  40 , a secondary slave heater  42  and a master heater  41 . The slave heater includes a safety shutoff flow switch  39  which, if it detects a flow rate of less than ½ gallon per minute, will turn off the heater to prevent heater damage. The three heaters  40 ,  41  and  42  are ideally fed a constant flow of water at a constant pressure and operate to maintain the desired temperature of the water which is preferably slightly lower than boiling. The heaters are controlled by the PLC  104 . The heated water exits the heater system and, referring now to FIG. 6B, either flows to the drain or flows to the hot fill valves. A pressure relief valve  43  will provide a safety bypass, if the pressure within the water heaters for some reason rises unexpectedly, allowing the release of pressure in the water lines and heater. 
     As the heated water exits the heater system, it has three options for flow. If the hot fill apparatus is not in use, the heated water flows through metering valve  48  and bypass valve  49 , which is controlled by the PLC  104  to the drain. If the hot fill apparatus is in use, the water will flow to either a manually operated spigot  47  through metering valve  46  or it will flow through the automatic fill nozzle apparatus through metering valve  50 . 
     Referring now to FIGS. 4,  5  and  6 B, the fill nozzle apparatus consists of a fill nozzle valve  51  which is controlled by the PLC  104  and feeds water to the fill nozzle apparatus  52 . The fill nozzle apparatus  52  consists of a carriage  53  positioned for vertical movement by an air cylinder  63  having a bottom position sensor  54  and a top position sensor  55 . The carriage  53  carries a fill head  44  mounted on a manually adjustable fill head height controller  45  and a resilient adjustable top load member  39 . The manually operated fill head height controller  45  is preferably used to make gross adjustments in the height of the fill head  44  while the force with which the automatic fill head engages the mouth of a container is controlled by top load member  39  and vertical movement of the fill head  44  which is activated by the automatic air pressure control system. 
     The top load member  39  includes a spring member  37  engaged between the fill head  44  and a manually adjustable dial  64 . A scale  65  indicating top load force is positioned to allow the operator to “dial in” the desired top load force by operating the dial  64  to compress or decompress the spring member  37 . The top load force is the desired force with which the fill head  44  engages the mouth of the container to test the ability of the container to withstand crushing or deforming forces during hot fill apparatus. 
     Referring to FIG. 6B, the automatic air pressure control system consists of an air inlet  62  which receives plant air which is processed through an inlet air filter and regulator  61  which sets the air pressure at, preferably, 40 psi. Exhaust silencers  59  and  60  are in place on the air line to quiet any air being exhausted from the air valve system when the hot fill apparatus is not in use. A solenoid control valve  58  is in communication with PLC  104  and is controlled thereby to feed air to the carriage cylinder  63  or exhaust air therefrom. When the air control system is engaged, the air pressure varies between speed control valves  56 ,  57 , thereby controlling vertical movement of the carriage  53  to engage or disengage the fill head  44  with the container. The PLC  104  will determine, through input by the operator, the bottle size and will automatically move the fill head  44  by means of the carriage  53  from an unengaged position to an engaged position with the container to provide an appropriate seal thereto. Once the fill head is engaged with the container, the fill nozzle valve  51  opens to allow a predetermined amount of hot water as determined by the PLC  104  to fill the bottle. The programmable logic controller instructs the fill nozzle valve  51  when to discontinue the flow of water through the fill nozzle and return the flow of water to dump to the drain. 
     The above description of the preferred embodiment of the hot fill apparatus of this invention is intended to be illustrative in nature and not limiting upon the scope and content of the following claims.