Abstract:
An apparatus, mounted to a mold, for injecting air into a mold cavity and removing exhaust from the mold cavity, comprising: a blow cylinder body block mounted to the mold having a conduit to the mold cavity, wherein the blow cylinder body block comprises an insulator and the conduit has walls; a needle passing through the blow cylinder body block and the conduit, wherein the needle is connected to a piston, wherein the needle has a needle passage, and wherein compressed air is applied to the piston to extend the needle into the mold cavity and retract the needle from the mold cavity; and an insulator between the needle and the conduit walls.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air injection and removal system. More specifically, the present invention relates to an insulated apparatus for injecting and removing compressed air from a cooled mold cavity. 
     2. Background of the Invention 
     Blow-molded plastic containers have become commonplace in packaging beverages, such as juice, and other hot and cold liquid products. Such a container normally has a dome, an annular sidewall extending from a base, and a waist connecting the dome to the sidewall. Typically, the containers have a horizontal cross section which is circular, rectangular or multi-faceted. Blow-molded plastic containers can provide a package with sufficient flexure to compensate for pressure and temperature, while maintaining structural integrity and aesthetic appearance. In addition, the plastic used in the containers is recyclable. 
     In a blow-molding process, a parison is inserted into the mold cavity, a needle is inserted into the parison, and the container is blown. In order to keep the mold cool to cool the mold cavity, the mold has passages filled with chilled water. During the blow-molding process, polymer volatiles are generated, and these polymer volatiles need to be vented. If the blow cylinder body block and the needle are not kept at a temperature that is higher than the mold, the polymer volatiles will condense on the needle and the passage inside the needle. Therefore, there is a need for an apparatus to keep the blow cylinder body block and the needle at a higher temperature than the mold to avoid premature condensing of polymer volatiles exhausting through the needle. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first embodiment, an apparatus, mounted to a mold, for injecting air into a mold cavity and removing exhaust from the mold cavity, comprises a blow cylinder body block mounted to the mold having a conduit to the mold cavity, wherein the blow cylinder body block comprises a first insulator and the conduit has walls; a needle passing through the blow cylinder body block and the conduit, wherein the needle is connected to a piston, wherein the needle has a needle passage, and wherein compressed air is applied to the piston to extend the needle into the mold cavity and retract the needle from the mold cavity; and a second insulator between the needle and the conduit walls. The first insulator may comprise Delrin®. The second insulator may be air. The apparatus further comprises a plurality of O-rings surrounding the needle to seal off air flow and exhaust. The apparatus further comprises a groove surrounding the needle in the blow cylinder body block. The apparatus further comprises a cylinder block; and a endcap, wherein the endcap, cylinder block and blow cylinder body block form a housing in which the piston is housed. The cylinder block and end cap comprise aluminum. The apparatus further comprises a first fitting connected to the housing through the endcap; a second fitting connected to the housing through the blow cylinder body block; and a third fitting passing through the blow cylinder body block and connected by an air passage to the needle. The first, second, and third fittings are coupled to a pneumatic drive for supplying compressed air to the first, second, and third fittings. 
     According to a second embodiment an apparatus, mounted to a mold, for injecting air into a mold cavity and removing exhaust from the mold cavity, comprises a blow cylinder body block mounted to the mold having a conduit to the mold cavity, wherein the conduit has walls; a needle passing through the blow cylinder body block and the conduit, wherein the needle is connected to a piston, wherein the needle has a needle passage, and wherein compressed air is applied to the piston to extend the needle into the mold cavity and retract the needle from the mold cavity; and a first insulator forming a layer on the conduit walls. The apparatus further comprises a second insulator between the first insulator and the conduit walls, wherein the second insulator is air. The apparatus further comprises a plurality of O-rings surrounding the needle to seal off air flow and exhaust. In the second embodiment the blow cylinder body block comprises aluminum. The first insulator may comprise Delrin®. The apparatus further comprises a groove surrounding the needle in the blow cylinder body block. The apparatus further comprises a cylinder block; and a endcap, wherein the endcap, cylinder block and blow cylinder body block form a housing in which the piston is housed. The apparatus further comprises a first fitting connected to the housing through the endcap; a second fitting connected to the housing through the blow cylinder body block; and a third fitting passing through the blow cylinder body block and connected by an air passage to the needle. The first, second, and third fittings are coupled to a pneumatic drive for supplying compressed air to the first, second, and third fittings. In the second embodiment, the blow cylinder body block, cylinder block and endcap comprise aluminum. Alternatively, in a third embodiment, the blow cylinder body block comprises an insulator. The insulator may comprise Delrin®. 
     According to a fourth embodiment, an apparatus, mounted to a mold having a mounting surface, for injecting air into a mold cavity and removing exhaust from the mold cavity, comprises a spacer; a blow cylinder body block mounted to the mold through a spacer forming an air gap between the mounting surface and the blow cylinder body block, wherein the mold has a conduit to the mold cavity and wherein the conduit has walls; a needle passing through the body and the conduit, wherein the needle has a needle passage, and wherein compressed air is applied to the piston to extend the needle into the mold cavity and retract the needle from the mold cavity; and an insulator between the needle and the conduit walls. The insulator is air. The apparatus further comprises a plurality of O-rings surrounding the needle to seal off air flow and exhaust. The apparatus further comprises a groove surrounding the needle in the blow cylinder body block. The apparatus further comprises a cylinder block; and a endcap, wherein the endcap, cylinder block and blow cylinder body block form a housing in which the piston is housed. The apparatus further comprises a first fitting connected to the housing through the endcap; a second fitting connected to the housing through the blow cylinder body block; and a third fitting passing through the blow cylinder body block and connected by an air passage to the needle. The first, second, and third fittings are coupled to a pneumatic drive for supplying compressed air to the first, second, and third fittings. The blow cylinder body block, cylinder block, and end cap comprise aluminum. The air gap is at least 0.03 inches. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross section of an injection and exhaust removal system of a first embodiment of the present invention; 
     FIG. 2 is a cross section of an air injection and exhaust removal system of a second embodiment of the present invention; 
     FIG. 3 is a cross section of an air injection and exhaust removal system of a third embodiment of the present invention; and 
     FIG. 4 is a cross section of an air injection and exhaust removal system of a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a first preferred embodiment of an air injection and removal system for injecting and removing air from a mold cavity  10 . A portion of the mold is identified by reference number  20 . The mold  20  has a conduit  21 , which extends from the mold cavity  10  to the air outside the mold cavity  10 . The conduit has walls  22 . 
     A needle block  25  is mounted to the mold  10  using screws  40 . (For simplicity, only one screw is shown). The needle block  25  includes a blow cylinder body block  30 , a cylinder block  34 , and a endcap  36 . Preferably, the cylinder block  34  and the endcap  36  are aluminum. The screws  40  pass through the blow cylinder body block  30  and into the mold  20  in order secure the blow cylinder body block  30  to the mold  20 . Preferably, there is no air gap between the blow cylinder body block  30  and the mold  20 . A needle  50 , connected to a piston  60 , passes through the blow cylinder body block  30  and has a passage  52  shown by dotted lines in FIG. 1. A pneumatic drive can supply air to the fittings,  62 ,  64 , and  66 . The pneumatic drive is compressed air, which is directed to flow through the fittings  62 ,  64 , and  66  preferably on a mechanical command to a valve, timed by the rotation of the blowmolding wheel (not shown). Compressed air supplied through fitting  62  pushes the piston  60  to the blow cylinder body block  30 , which extends the needle  50  into the mold cavity  10 . When the needle  50  is extended into the mold cavity  10  as shown in FIG. 1, the pneumatic drive stops the supply of compressed air through fitting  62 . Compressed air, supplied through fitting  64 , enters the mold cavity  10  by way of the needle passage  52 . 
     After a predetermined time, the pneumatic drive stops supplying air through fitting  64 . Subsequently, the pneumatic drive supplies compressed air to the fitting  66  to move the piston  60  away from the blow cylinder body block  30  and toward the endcap  36 , so that the needle  50  is retracted from the mold cavity  10 . Exhaust from the mold cavity  10  enters the conduit  21  and travels through the needle passage  52 . In the retracted position, the needle passage  52  connects to a groove  70 , which vents the exhaust from the needle block  25 . The O-rings  72 ,  74 , and  76  seal off air flow and exhaust as the needle  50  extends into the mold cavity  10  and retracts from the mold cavity  10 . 
     An insulator  80 , which is preferably air, fills the space between the walls  22  of the conduit and the needle  50 , to prevent the cold temperature of the mold  20  from decreasing the temperature of the air delivered through the needle  50  to the mold cavity  10 . In the first embodiment, the blow cylinder body block  30  preferably comprises an insulator (e.g., Delrin®), which also insulates the cool air delivered through the needle  50  to the mold cavity  10 . Delrin® is an acetal resin. Delrin® is not a thermoconductor. Moreover, insulator  80  and the blow cylinder body block  30  isolate the needle  50 , which carries the exhaust from the cold mold  20 . This prevents the condensation of the polymer volatiles on the outside of the needle  50  and in the needle passage  52 . 
     FIG. 2 shows a second preferred embodiment of an air injection and removal system for injecting and removing air from a mold cavity  10 . A portion of the mold is identified by reference number  20 . The mold  20  has a conduit  21 , which extends from the mold cavity  10  to the air outside the mold cavity  10 . The conduit has walls  22 . 
     A needle block  26  is mounted to the mold  10  using screws  40 . (For simplicity, only one screw is shown). The needle block  26  includes a blow cylinder body block  35 , a cylinder block  34 , and a endcap  36 . Preferably, the cylinder block  34 , and the endcap  36  are aluminum. The screws  40  pass through the blow cylinder body block  35  and into the mold  20  in order secure the blow cylinder body block  35  to the mold  20 . Preferably, there is no air gap between the blow cylinder body block  35  and the mold  20 . A needle  50 , connected to a piston  60 , passes through the blow cylinder body block  35  and has a passage  52  shown by dotted lines in FIG. 2. A pneumatic drive can supply air to the fittings,  62 ,  64 , and  66 . The pneumatic drive is compressed air, which is directed to flow through the fittings  62 ,  64 , and  66  preferably on a mechanical command to a valve, timed by the rotation of the blowmolding wheel (not shown). Compressed air supplied through fitting  62  pushes the piston  60  to the blow cylinder body block  35 , which extends the needle  50  into the mold cavity  10 . When the needle  50  is extended into the mold cavity  10  as shown in FIG. 2, the pneumatic drive stops the supply of compressed air through fitting  62 . Compressed air, supplied through fitting  64 , enters the mold cavity  10  by way of the needle passage  52 . 
     After a predetermined time, the pneumatic drive stops supplying air through fitting  64 . Subsequently, the pneumatic drive supplies compressed air to the fitting  66  to move the piston  60  away from the blow cylinder body block  35  and toward the endcap  36 , so that the needle  50  is retracted from the mold cavity  10 . Exhaust from the mold cavity  10  enters the conduit  21  and travels through the needle passage  52 . In the retracted position, the needle passage  52  connects to a groove  70 , which vents the exhaust from the needle block  26 . The O-rings  72 ,  74 , and  76  seal off air flow and exhaust as the needle  50  extends into the mold cavity  10  and retracts from the mold cavity  10 . 
     Insulator  85 , which is preferably Delrin®, forms a layer along the walls  22  of the conduit  21 . Insulator  80 , which is preferably air, fills the space between the insulator  85  and the needle  50 . Both insulators  80  and  85  prevent the cold temperature of the mold  20  from decreasing the temperature of the air delivered through the needle  50  to the mold cavity  10 . In the second embodiment, the blow cylinder body block  35  preferably comprises aluminum. Moreover, insulators  80  and  85  isolate the needle  50 , which carries the exhaust from the cold mold  20 . This prevents the condensation of the polymer volatiles on the outside of the needle  50  and in the needle passage  52 . 
     FIG. 3 shows a third preferred embodiment of an air injection and removal system for injecting and removing air from a mold cavity  10 . A portion of the mold is identified by reference number  20 . The mold  20  has a conduit  21 , which extends from the mold cavity  10  to the air outside the mold cavity  10 . The conduit has walls  22 . 
     A needle block  27  is mounted to the mold  10  using screws  40 . (For simplicity, only one screw is shown). The needle block  27  includes a blow cylinder body block  30 , a cylinder block  34 , and a endcap  36 . Preferably, the cylinder block  34  and the endcap  36  are aluminum. The screws  40  pass through the blow cylinder body block  30  and into the mold  20  in order secure the blow cylinder body block  30  to the mold  20 . Preferably, there is no air gap between the blow cylinder body block  30  and the mold  20 . A needle  50 , connected to a piston  60 , passes through the blow cylinder body block  30  and has a passage  52  shown by dotted lines in FIG. 3. A pneumatic drive can supply air to the fittings,  62 ,  64 , and  66 . The pneumatic drive is compressed air, which is directed to flow through the fittings  62 ,  64 , and  66  preferably on a mechanical command to a valve, timed by the rotation of the blowmolding wheel (not shown). Compressed air supplied through fitting  62  pushes the piston  60  to the blow cylinder body block  30 , which extends the needle  50  into the mold cavity  10 . When the needle  50  is extended into the mold cavity  10  as shown in FIG. 3, the pneumatic drive stops the supply of compressed air through fitting  62 . Compressed air, supplied through fitting  64 , enters the mold cavity  10  by way of the needle passage  52 . 
     After a predetermined time, the pneumatic drive stops supplying air through fitting  64 . Subsequently, the pneumatic drive supplies compressed air to the fitting  66  to move the piston  60  away from the blow cylinder body block  30  and toward the endcap  36 , so that the needle  50  is retracted from the mold cavity  10 . Exhaust from the mold cavity  10  enters the conduit  21  and travels through the needle passage  52 . In the retracted position, the needle passage  52  connects to a groove  70 , which vents the exhaust from the needle block  27 . The O-rings  72 ,  74 , and  76  seal off air flow and exhaust as the needle  50  extends into the mold cavity  10  and retracts from the mold cavity  10 . 
     Insulator  85 , which is preferably Delrin®, forms a layer along the walls  22  of the conduit  21 . Insulator  80 , which is preferably air, fills the space between the insulator  85  and the needle  50 . Both insulators  80  and  85  prevent the cold temperature of the mold  20  from decreasing the temperature of the air delivered through the needle  50  to the mold cavity  10 . In the third embodiment, the blow cylinder body block  30  preferably comprises an insulator, e.g. Delrin®). Moreover, insulators  80  and  85  isolate the needle  50 , which carries the exhaust from the cold mold  20 . This prevents the condensation of the polymer volatiles on the outside of the needle  50  and in the needle passage  52 . 
     FIG. 4 shows a fourth preferred embodiment of an air injection and removal system for injecting and removing air from a mold cavity  10 . A portion of the mold is identified by reference number  20 . The mold  20  has a conduit  21 , which extends from the mold cavity  10  to the air outside the mold cavity  10 . The conduit has walls  22 . 
     A needle block  26  is mounted to the mold  10  using screws  40 . (For simplicity, only one screw is shown). The needle block  26  includes a blow cylinder body block  35 , a cylinder block  34 , and a endcap  36 . Preferably, the cylinder block  34  and the endcap  36  are aluminum. The screws  40  pass through the blow cylinder body block  35  and into the mold  20  in order secure the blow cylinder body block  35  to the mold  20 . Preferably, there is a small contact mounting pad or spacer  90  between the blow cylinder body block  35  and the mold  20 . The spacer  90  permits an air gap to be formed between part of the blow cylinder body block  35  and mold  20  to further isolate the air or exhaust moving through the needle  50 . The air gap is relatively small. The air gap is approximately 0.03 inches. Although the air gap could be slightly less than 0.03 inches, the air gap is preferably at least 0.03 inches. 
     A needle  50 , connected to a piston  60 , passes through the cylinder body block  35  and has a passage  52  shown by dotted lines in FIG. 4. A pneumatic drive can supply air to the fittings,  62 ,  64 , and  66 . The pneumatic drive is compressed air, which is directed to flow through the fittings  62 ,  64 , and  66  preferably on a mechanical command to a valve, timed by the rotation of the blowmolding wheel (not shown). Compressed air supplied through fitting  62  pushes the piston  60  to the blow cylinder body block  35 , which extends the needle into the mold cavity  10 . When the needle is extended into the mold cavity  10  as shown in FIG. 4, the pneumatic drive stops the supply of compressed air through fitting  62 . Compressed air, supplied through fitting  64 , enters the mold cavity  10  by way of the needle passage  52 . 
     After a predetermined time, the pneumatic drive stops supplying air through fitting  64 . Subsequently, the pneumatic drive supplies compressed air to the fitting  66  to move the piston  60  away from the blow cylinder body block  35  and toward the endcap  36 , so that the needle  50  is retracted from the mold cavity  10 . Exhaust from the mold cavity  10  enters the conduit  21  and travels through the needle passage  52 . In the retracted position, the needle passage  52  connects to a groove  70 , which vents the exhaust from the needle block  26 . The O-rings  72 ,  74 , and  76  seal off air flow and exhaust as the needle  50  extends into the mold cavity  10  and retracts from the mold cavity  10 . 
     An insulator  80 , which is preferably air, fills the space between the walls  22  of the conduit and the needle  50 , to prevent the cold temperature of the mold  20  from decreasing the temperature of the air delivered through the needle  50  to the mold cavity  10 . In the third embodiment, the blow cylinder body block  35  preferably comprises aluminum. Moreover, insulator  80  isolate the needle  50 , which carries the exhaust from the cold mold  20 . This prevents the condensation of the polymer volatiles on the outside of the needle  50  and the needle passage  52 . 
     Any of these embodiments or variations thereof may be utilized to enhance a conventional extrusion blow molding process. The conventional blow molding process begins with forming a parison on a flow head to form a hollow tube (not shown). The tube is placed between the mold halves and the mold is closed. Compressed air is supplied through fitting  62  to the piston  60 . The piston  60  pushes the needle  50  into the parison and air pressure blows through the needle  50  into the parison to blow the parison to form the container. Subsequently, the supply of air through the needle  50  is terminated. The needle  50  retracts and allows the exhaust to pass through the passage  52 . The exhaust is then vented from groove  70 . 
     Therefore, any of these embodiments or variations thereof may be utilized in an extrusion blow molding process to isolate the mold cooling temperature from the air injection and exhaust system. These embodiments provide the additional advantages of very substantially reducing the amount of polymer volatiles that condense from the exhaust onto the needle  50 , the cavity surrounding the needle  50 , and the needle passage  52  in blow molding apparatus. These advantages provide a more efficient air injection and exhaust removal system and extends the time between servicing and cleaning of the mold  20 . 
     While the invention has been described in detail with reference to specific and preferred embodiments, it will be appreciated that various modifications and variations will be apparent to the artisan. All such modifications and embodiments as may occur to one skilled in the art are intended to be within the scope of the appended claims.