Abstract:
The invention includes a calibrator washer apparatus and a method for cleaning extrusion calibrators such as a calibrator used in the extrusion of a hollow, thin walled polyvinyl profile for use in the fenestration industry. The inventive calibrator cleaning method involves scrubbing the interior calibration surface of the calibrator with a bristle brush, pumping a hot water and detergent cleaning fluid through the calibrator vacuum ports that connect to the vacuum slots in the interior calibration surface, pumping hot water through calibrator vacuum ports that connect to the vacuum slots in the interior calibration surface to rinse off the detergent. The method may further include running cool water through the calibrator vacuum ports to cool the calibrator and wiping down the cleaned calibrator with a water-displacing lubricant. The inventive calibrator washer includes a cleaning fluid tank containing a cleaning fluid, a rinse fluid tank containing a rinse fluid, a main washer tank which is consecutively supplied with and contains the wash fluid and then is supplied with and contains the rinse fluid, at least one main pump that consecutively pumps the cleaning fluid and then the rinse fluid from the main washer tank through a calibrator and back into main washer tank, and a transfer pump to consecutively empty the main washer tank of the cleaning fluid and return the cleaning fluid to the cleaning fluid tank and to empty the main washer tank of the rinse fluid and return it to the rinse fluid tank.

Description:
PRIORITY  
       [0001]     This application claims the benefit of the filing date of co-pending U.S. Provisional Application No.: 60/616,197, filed Oct. 4, 2004. 
     
    
     TECHNICAL FIELD  
       [0002]     The invention concerns a machine for cleaning calibrators for thin walled plastic extrusions allowing the cleaning of such a calibrator without full disassembly of the calibrator.  
       BACKGROUND OF THE INVENTION  
       [0003]     In order to manufacture thin-walled plastic extrusions and foamed extrusions, various basic components are required including an extruder, a die, a calibrator, cooling tank, puller and a saw as is well understood by persons of ordinary skill in the art. The calibrators are designed to keep the hollow, thin-walled extrusion from collapsing and to allow a foamed extrusion to properly expand and further to size an extrusion to its final desired dimensions. In order to keep the exterior walls of the extrusion against the interior walls of the calibrator, the calibrator typically include numerous vacuum slots at various places along the length of the interior walls of the calibrator where the vacuum slots are connected to a vacuum port which is further connected to a vacuum pump. Thus, the vacuum acting against the extrusion acts to keep it against the interior walls of the calibrator allowing it to cool at the desired shape and dimensions.  
         [0004]     As one would expect, such a use of calibrators would cause the extrusion to come in contact with the walls of the calibrator which would allow build up of residue upon the interior walls of the calibrator. In addition, the vacuum on the vacuum slots causes various residues, typically melted waxes, additives or extrusion process aids, to build-up within the vacuum slots and within the passageways that connect the vacuum slots to the vacuum port. As even small amounts of residue on the interior surface of the calibrator cause changes in the shape and surface finish of the extrudate, it is necessary to periodically clean the calibrator.  
         [0005]     The prior art method for cleaning the calibrator requires the complete disassembly of the calibrator. The calibrator is made up of a plurality of plates allowing precise vacuum slots and other features to be manufactured by machining notches in the face of an individual plate. When the plates are bolted together, the notches in one or more of the faces together form a vacuum slot. While this method dramatically simplifies the manufacture of a calibrator, it requires that the individual plates be precisely aligned and that each plate precisely mate with its neighbors to form the proper shape. Thus, the full disassembly and reassembly of the plates of the calibrator for regular periodic cleaning consumes substantial amounts of time, and introduces a significant risk of improper alignment of the plates within the calibrator that would cause the calibrator to work improperly when next used in production of an extrusion.  
       SUMMARY OF THE INVENTION  
       [0006]     It is an object of the invention to provide for a method and equipment for the cleaning of extrusion calibrators without full disassembly of the calibrator plates. The inventive machine and method of cleaning a calibrator allows a calibrator to be cleaned without disassembling the plates.  
         [0007]     The inventive calibrator cleaning method involves scrubbing the interior calibration surface of the calibrator with a bristle brush, pumping a hot water and detergent cleaning fluid through the calibrator vacuum ports that connect to the vacuum slots in the interior calibration surface, pumping hot water through calibrator vacuum ports that connect to the vacuum slots in the interior calibration surface to rinse off the detergent. The method may further include running cool water through the calibrator vacuum ports to cool the calibrator and wiping down the cleaned calibrator with a water-displacing lubricant.  
         [0008]     The inventive calibrator washer includes a cleaning fluid tank containing a cleaning fluid, a rinse fluid tank containing a rinse fluid, a main washer tank which is consecutively supplied with and contains the wash fluid and then is supplied with and contains the rinse fluid, at least one main pump that consecutively pumps the cleaning fluid and then the rinse fluid from the main washer tank through a calibrator and back into main washer tank, and a transfer pump to consecutively empty the main washer tank of the cleaning fluid and return the cleaning fluid to the cleaning fluid tank and to empty the main washer tank of the rinse fluid and return it to the rinse fluid tank. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an isometric view of a novel calibrator washing machine for use in the inventive process showing calibrators on in-feed and out-feed tables and transfer carts.  
         [0010]      FIG. 2  is a cutaway view of a main washer tank assembly of the novel calibrator washing machine.  
         [0011]      FIG. 3  is a cutaway view of the main washer tank assembly of the novel calibrator washing machine with a calibrator attached to and in position to be washed by the novel calibrator washing machine.  
         [0012]      FIG. 4  is a plan view of the back of the novel calibrator washing machine with the safety covers removed.  
         [0013]      FIG. 5  is a plan view of the front of the novel calibrator washing machine with the safety covers removed.  
         [0014]      FIG. 6  is a plan view of the left side of the novel calibrator washing machine with the safety covers removed.  
         [0015]      FIG. 7  is a plan view of the right side of the novel calibrator washing machine with the safety covers removed. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Disclosed in the drawings is a preferred embodiment of a calibrator washing machine, referred to generally with numeral  10 , which allows cleaning without disassembly of the plates of plastic extrusion calibrators. The disclosed calibrator washing machine (or washer)  10  will be further detailed below, but the general manner of its use and operation will be here described with reference to  FIG. 1 . Prior to using washer  10 , an operator would first scrub the interior calibration surface of the calibrator  12 ,  14 , for example with a nylon long handled brush. The calibration surface is a unique shape that determines the final shape of the extrudate produced on an extrusion line as is well understood by a person of ordinary skill in the art and may be a single tool as in the calibrator designated at numeral  12  or it may be a dual tool such as the calibrator referenced at numeral  14  where two profiles are produced on an extrusion line. Calibrators  12 ,  14  typically have lower and upper vacuum ports  13 . The operator of washer  10  would load the calibrator  12 ,  14  from cart  16  or from a crane (not shown) onto in-feed table  18 . The calibrator  12 ,  14  is then moved from the in-feed table  18  into the main washer tank assembly  20 . The main washer tank assembly  20  is covered by hood  22  and is lifted by the operator with handle  24  when the lock  26  is disengaged by the controller for the washer  10 .  
         [0017]     The interior of the main washer tank assembly  20  underneath hood  22  can be seen in cutaway form in  FIGS. 2 and 3 . As can be seen in  FIGS. 2 and 3 , the operator would attach either right manifold hoses  28  or left manifold hoses  30  to vacuum ports  13  of the calibrator as will be further discussed below and would open a ball valve  31  for each hose  28 ,  30  that is connected to a vacuum port  13  understanding that the ball valves  31  regulate the flow of fluid to each hose  28 ,  30 . The operator would also open a ball valve  31  connected to an exterior spray line  32  that includes supplies nozzles  33  which will spray the exterior of the calibrator  12 ,  14 . Right manifold hoses  28  are operatively connected to a right manifold  34  and left manifold hoses  30  are operatively connected to a left manifold  36  where the right manifold  34  and left manifold  36  are connected to two separate pumps allowing efficient cleaning of a dual calibrator  14 , a single calibrator  12 , or two single calibrators  12  as will be fully described herein below. The fluid pumped through the calibrator  12 ,  14  is collected in main washer tank  37 . It should be noted that the calibrator  12 ,  14  is easily moved on the in-feed table on omni-directional rollers  40  ( FIG. 1 ) and in the main washer tank assembly on bi-directional rollers  38  that allow the calibrator  12 ,  14  to move towards or away from the in-feed table  18 . Float gauge  41  measures the fluid level in the main washer tank  37 .  
         [0018]     The operator inputs to the controller  42  whether a (a) a single calibrator  12  or (b) a dual calibrator  14  or two single calibrators  12  is (are) to be cleaned. If a single calibrator is to be cleaned, the operator would have connected the left manifold hoses  30  to the vacuum ports  13  of calibrator  12 . If a dual calibrator  14  or two single calibrators is (are) to be cleaned, the operator would connect both the left manifold hoses  30  and the right manifold hoses  28  to the vacuum ports  13  of calibrator  14 . The operator then closes hood  22  with handle  24  and the controller  42  initiates lock  26  and starts the cleaning cycle. As will be fully explained below, the washer  10  first pumps heated cleaning fluid comprised of water and detergent into the vacuum ports  13  and out the vacuum slots of the calibrator  12 ,  14  while the nozzles  33  spray the exterior of the calibrator  12 ,  14 . The washer  10  then does likewise with heated rinse water and upon completion of the rinse, turns on a fan for a set period of time (not shown) to evacuate the steam from the hood  22 . After the steam is evacuated, the controller  42  releases lock  26  allowing hood  22  to be opened by the operator. Operator would then move the calibrator  12 ,  14  to the out-feed table  46 . After the calibrator  12 ,  14  has cooled either by passage of time or by active cooling with cool water, the operator would dry it with compressed air and then lightly coat it with a water-displacing oil such as WD-40 to prevent rust formation.  
         [0019]     Referring now to  FIGS. 4, 5  and  6 , washer  10  includes an upper tank assembly  48  that includes a cleaning fluid tank  50  on the left (when viewed from the front) and on the right a rinse fluid tank  52  having, respectively, a cleaning fluid level gauge  54  and a rinse fluid level gauge  56 . Rinse water supply piston valve  58  is opened by controller  42  when the level of rinse water in the rinse water tank drops below a predetermined level on rinse fluid level gauge  56 . An overflow pipe and vent (not shown) exits the top of the upper tank assembly to prevent pressure or vacuum in the upper tank assembly  48  when either the cleaning fluid or rinse fluid is moved in or out of their respective tanks. Cleaning fluid drop piston valve  60  is operatively connected to the bottom of cleaning fluid tank  50  at one end and further connects to a cleaning fluid drop pipe  62  which drains into the washer fluid input port  64  which flows into the main washer tank  37  as can be best seen in  FIG. 6 .  
         [0020]     As best seen in  FIGS. 4, 5  and  6 , left main pump  66  draws fluid from the main washer tank  37  through left pump input line  68 . Left main pump  66  is a 15 horsepower water pump which is supplied with 3-phase, 480 VAC power. Left main pump  66  outputs to a pressure relief piston valve  70  which will open and allow flow through relief line  72  back to main washer tank  37  should excess pressure build and restrict flow through pump  66 . In normal operation, the relief piston valve  70  remains closed and the flow from pump  66  goes to filter supply line  74  and then past left filter vacuum relief piston valve  76  which remains closed when pump  66  is operating forcing the fluid to flow into left fluid filter  78 . From vacuum relief piston valve  76 , flow continues through left fluid filter  78  which filters particles of significant size from the fluid. Fluid flows from the inlet at the top to the bottom of left fluid filter  78  which outputs to filter output tee  80  which is connected to one end of left manifold input line  82  which connects at its other end to the left manifold  36  which can be seen in  FIGS. 2 and 3  and was described above.  
         [0021]     Referring now to  FIGS. 4, 5  and  7 , as described above, washer  10  upper tank assembly  48  included a rinse fluid tank  52 , and a vent in the upper tank assembly  48  to prevent pressure or vacuum in the upper tank assembly when either the cleaning fluid or rinse fluid is moved in or out of their respective tanks. Additionally, rinse fluid drop piston valve  84  is operatively connected to the bottom of rinse fluid tank  52  at one end and further connects to a rinse fluid drop pipe  86  which drains into the washer fluid input port  64  which flows into the main washer tank  37  as can be best seen in  FIG. 7 .  
         [0022]     As best seen in  FIGS. 4 and 7 , in a similar manner to the left main pump  66  and associated equipment, a right main pump  90  draws fluid from the main washer tank  37  through right pump input line  92 . Right main pump  90  is also a 15 horsepower water pump supplied with 3-phase, 480 VAC power. Right main pump  90  outputs to an over-pressure relief piston valve  94  which will open and allow flow through relief line  96  back to main washer tank  37  should excess pressure build and restrict flow through pump  90 . In normal operation, the over-pressure relief piston valve  94  remains closed and the flow from pump  90  goes to filter supply line  98  and then to right filter vacuum relief piston valve  100  which remains closed when pump  90  is operating forcing the fluid to flow into right fluid filter  102 . From vacuum relief piston valve  100 , flow continues through right fluid filter  102  which filters particles of significant size from the fluid. Fluid flows from the inlet at the top to the bottom of right fluid filter  102  which outputs to filter output tee  104  which is connected to one end of right manifold input line  106  which connects at its other end to the right manifold  38  which can be seen in  FIGS. 2 and 3  and was described above.  
         [0023]     With reference to  FIGS. 4, 6  and  7 , transfer pump  108  pumps fluid to the upper transfer pump junction  110  from the lower transfer pump junction  112 . Upper junction  110  is connected to both a cleaning fluid return piston valve  114  and a rinse fluid return valve  118 . The cleaning fluid return piston valve  114  is further connected to cleaning fluid return line  116  which allows flow into the cleaning fluid tank  50  as can best be seen in  FIG. 6 . Upper junction  110  also connects to rinse fluid return piston valve  118  which is further connected to rinse fluid return line  120  that allows flow into the rinse fluid tank  52  as can be seen in  FIG. 7 . Lower transfer pump junction  112  connects transfer pump  108  to drain line  122  allows flow from the bottom of main washer tank  37 . A filter drain tee  124  is attached to the back wall of the main washer tank  37  and allows flow into main washer tank  37  from a left filter drain piston valve  126  the input of which is connected to the left filter output tee  80  in addition to the left manifold input line  82 . Likewise, filter drain tee  124  allows flow into the main washer tank  37  from connected right filter drain piston valve  128  which is connected to the right filter output tee  104  in addition to the right manifold input line  106 .  
         [0024]     A complete cycle of the operation of the washer  10  will now be described in light of the various components described hereinabove. The washer begins with the washing fluid tank  50  and the rinse fluid tank  62  essentially full of containing cleaning fluid and rinse fluid, respectively, and the main washer tank essentially empty of fluid and all piston valves closed. The operator enters into the controller  42  whether (a) a single calibrator  12  or (b) a dual calibrator  14  or two single calibrators  12  is to be cleaned and positions the calibrator  12 ,  14  beneath the hood  22  and connects the hoses  28 ,  30  and opens ball valves  31  as described hereinabove, namely connects  28  if only washing a single calibrator  12  or connects both hoses  28  and hoses  30  if washing a dual calibrator  14  or two single calibrators  12 . The controller  42  then opens cleaning fluid drop piston valve  60  allowing the cleaning fluid to drain from the cleaning fluid tank  50  down through cleaning fluid drop pipe  62  into the washer fluid input port  64  thereby filing the main washer tank  37 . When the main washer tank fluid level gauge  41  in main washer tank  37  reaches a predetermined level, the controller  42  closes cleaning fluid drop piston valve  60 . Controller  42  checks that hood  22  is closed and then engages lock  26 .  
         [0025]     Next, the controller  42  opens a relay to start left main pump  66  which pulls the cleaning fluid from main tank  37  through left pump input line  68 . Left main pump  66  outputs the cleaning fluid past the closed pressure relief piston valve  70  to filter supply line  74  and then through left filter vacuum relief piston valve  76  which remains closed forcing the cleaning fluid to flow into and through left fluid filter  78  which filters particles of significant size from the fluid. The cleaning fluid flows through filter output tee  80  and through left manifold input line  82  and thereby into the left manifold  36 . Left manifold  36  supplies the cleaning fluid through respective open ball valves  31  into left manifold hoses  30  connected to vacuum ports  13  of the calibrator  12 ,  14  and through an open ball valve  31  connected to the exterior spray line  32  supplying nozzles  33  thereby spraying the exterior of the calibrator  12 ,  14 . The cleaning fluid flows out of the nozzles  33  and out of the vacuum slots and out of the profile openings in the ends of calibrator  12 ,  14  and drains back into the main washer tank  37 .  
         [0026]     If the operator has indicated that washer  10  will be cleaning a dual calibrator  14  or two single calibrators  12 , then controller  42  will start the right main pump  90  in addition to the left main pump  66 . Similarly, right main pump  90  outputs the cleaning fluid past the closed pressure relief piston valve  94  to filter supply line  98  and then through right filter vacuum relief piston valve  100  which remains closed forcing the cleaning fluid to flow into and through right fluid filter  102  which filters particles of significant size from the cleaning fluid. The cleaning fluid flows through right filter output tee  104  and through right manifold input line  106  and thereby into the right manifold  38 . Right manifold  38  supplies the cleaning fluid through respective open ball valves  31  into right manifold hoses  28  connected to vacuum ports  13  of the calibrator  14  and through an open ball valve  31  connected to the exterior spray line  32  jointly with left main pump  66  supplying nozzles  33  thereby spraying the exterior of the calibrator  14 . The cleaning fluid flows out of the nozzles  33  and out of the vacuum slots and then out of the ends of calibrator  14  and drains back into the main washer tank  37 . The left main pump and as required for a dual calibrator  14  or two single calibrators  12 , the right main pump, will be stopped by the controller  42  after a predetermined period of time completing the cleaning portion of the cycle.  
         [0027]     Next the washer  10  will return the cleaning fluid to the cleaning fluid tank  50 . First, the controller  42  will open the right filter vacuum relief piston valve  100 , the left filter vacuum relief piston valve  76 , the left filter drain piston valve  126 , the right filter drain piston valve  128  (if running a dual calibrator  14  or two single calibrators  12 ), and the cleaning fluid return piston valve  114  and will start the transfer pump  108 . Transfer pump  108  will then pull the cleaning fluid from the main washer tank  37  through the lower transfer pump junction  112  which pulls from drain line  122  which connects to the bottom of main washer tank  37 . Since the left filter vacuum relief piston valve  76  is open, the filter drain tee  124  drains from the left fluid filter  78  into the main washer tank  37  since filter  78  is higher in elevation than bottom of main washer tank  37  that is being pumped out by transfer pump  108  through drain line  122 . Likewise, since the right filter vacuum relief piston valve  100  and the right filter drain piston valve  128  are open, the filter drain tee  124  drains from the right fluid filter  102  into the main washer tank  37  that is being pumped out by transfer pump  108  through drain line  122  from lower transfer pump junction  112 . Also, since the left filter vacuum relief piston valve  76  is open and left main pump  66  is off, the cleaning fluid in filter supply line  74  and left main pump  66  will drain into main washer tank  37  through left pump input line  68 . Likewise, since the right filter vacuum relief piston valve  100  is open and right main pump  90  is off, the cleaning fluid in filter supply line  98  and right main pump  90  will drain into main washer tank  37  through right pump input line  92 .  
         [0028]     Transfer pump  108  pumps fluid to the upper transfer pump junction  110  from the lower transfer pump junction  112  and up through the open cleaning fluid return piston valve  114  through cleaning fluid return line  116  and into the cleaning fluid tank  50 . When the fluid level gauge  41  in main washer tank  37  reaches a predetermined level indicating that the tank is empty, the controller  42  stops transfer pump  108  and closes the right filter vacuum relief piston valve  100 , the left filter vacuum relief piston valve  76 , the left filter drain piston valve  126 , the right filter drain piston valve  128  if running a dual calibrator  14  or two single calibrators  12 , and the cleaning fluid return piston valve  114 . Here, the main washer tank  37  and left and right main pumps  66 ,  90  and left and right fluid filters  78 ,  102  are essentially empty to limit the amount of cleaning fluid not returned to cleaning fluid tank  50 .  
         [0029]     Next, washer  10  performs the rinse portion of the cycle. Controller  42  opens rinse fluid drop piston valve  84  allowing the rinse fluid to drain from the rinse fluid tank  52  down through rinse fluid drop pipe  86  into the rinse fluid input port  88  thereby filing the main washer tank  37 . When the main washer tank fluid level gauge  41  in main washer tank  37  reaches a predetermined level, the controller  42  closes rinse fluid drop piston valve  84 . In an identical manner to the process described above for the washing fluid, the washer  10  pumps rinse fluid through the calibrator  12 ,  14  for a predetermined time. Washer  10  then returns the rinse fluid to the rinse fluid tank  52  in an identical manner as described for the cleaning fluid except that the cleaning fluid return valve  114  remains closed and instead the rinse fluid return valve  118  is opened.  
         [0030]     It should be noted that the cleaning fluid tank  50  and the rinse fluid tank  52  include fluid level gauges that function as fluid level gauge  41  in the main washer tank  37 . Controller  42  can be programmed remind the operator to add additional supply fluid to the respective tank  50 ,  52  when the level drops below a predetermined point. In addition, if the fluid level in main washer tank  37  drops below a predetermined point, controller  42  will open either the cleaning fluid or the rinse fluid drop piston valves  60 ,  84  allowing either cleaning fluid or rinse fluid to drain from the cleaning or rinse fluid tank  50 ,  52  filing the main washer tank  37  with cleaning or rinse fluid depending on which is currently in use. Thus, spray or vapor loss of fluid during a cleaning or rinse cycle will not cause too little fluid to remain in main washer tank  37  for proper use by right and left main pumps  66 ,  90 . In addition, washer fluid tank  50 , rinse fluid  52  and main washer tank  37  include self contained heater coils indicated at reference numerals  130 ,  132  and  134 , respectively.  
         [0031]     The preferred cleaning fluid is LF2100 liquid low-foam cleaner diluted in water. LF2100 is available from International Products Corporation of Burlington, N.J. Aqua Mate 86 parts wash diluted in water, available from Chemlogis of Tualatin, Oreg. will also work with the machinery and process herein described. Self-contained heater coils  130 ,  132  and  134  are preferably set at 180° F. keeping the cleaning and rinse fluids at approximately that temperature as 180  F. is significantly higher than the wax transition phase temperature that is typically a major component of the residue deposited in a calibrator. The pressure relief piston valves  70 ,  94  are preferably set at 90 psi as such pressures do not damage the components of the washer  10  or of the calibrators  12 ,  14 . Main pumps  66 ,  90  are 15 horsepower as this flowed enough fluid through ¾ inch or 1 inch vacuum ports  13  below a pressure of approximately 90 psi to allow a cycle time of 15 minutes of pumping cleaning fluid and 5 minutes of pumping rinse fluid. This cycle time would allow cleaning of four to six calibrators 12 per man-hour where as the prior art method typically would require approximately one calibrator per man-hour. The cycle time and amount of cleaner can be optimized for particular calibrators and/or extrusions processes to achieve the maximum throughput while allowing the proper cleaning of calibrators  12 ,  14 .