Mold assembly having a pressure reducing device
View Patent ↗Disclosed is a preferred mold design for producing plastic, molded preforms, which may be blow-molded into a container of a final, desired shape. A preferred mold includes a temperature control system for maintaining the preform mold at a desired temperature. The temperature control system can pass fluid through channels within the preform mold to cool plastic that is injected into the preform mold. In some arrangements, a mold comprises a neck finish mold, the neck finish mold comprising high heat transfer material positioned to transfer heat away from melt within a mold cavity of the mold.
1. A mold comprising:
a core section having a core surface;
a cavity section having a cavity surface, a mold cavity being defined by the core surface and the cavity surface when the mold is in a closed position;
at least one fluid channel being disposed within one of the core section and the cavity section; and
a pressure reducing device in fluid communication with the fluid channel, the pressure reducing device being configured to receive and at least partially vaporize a volume of a refrigerant.
2. The mold of claim 1 , wherein the pressure reducing device comprises a valve.
3. The mold of claim 2 , wherein the pressure reducing device comprises a nozzle valve or a needle valve.
4. The mold of claim 2 , wherein the pressure reducing device comprises an expansion valve with a fixed diameter orifice.
5. The mold of claim 1 , wherein the refrigerant comprises nitrogen or carbon dioxide.
6. The mold of claim 1 , wherein the mold is a compression mold or an injection mold.
7. The mold of claim 1 , wherein the fluid channel is part of an open-loop system.
8. The mold of claim 1 , wherein the fluid channel is part of a closed-loop system.
9. The mold of claim 1 , wherein the pressure reducing device is located at least partially within the core section or the cavity section.
10. The mold of claim 1 , wherein the pressure reducing device is located outside of the core section or the cavity section.
11. The mold of claim 1 , further comprising a flow regulator positioned upstream of the pressure reducing device, the flow regulator being configured to selectively control a flow rate at which the refrigerant enters the pressure reducing device.
12. The mold of claim 1 , further comprising a temperature control element configured to selectively heat or cool at least a portion of the mold.
13. The mold of claim 12 , wherein the temperature control element comprises a resistance heater.
14. A mold assembly comprising:
a core section;
a cavity section, a mold cavity being defined by the core section and the cavity section when the mold assembly is in a closed position; and
a temperature control system configured to transfer heat away from the mold cavity, the temperature control system comprising:
at least one fluid channel located within one of the core section and cavity section; and
a pressure reducing device in fluid communication with the fluid channel, the pressure reducing device being configured to receive a volume of a refrigerant and to at least partially reduce a pressure of the refrigerant to an outlet pressure equal to or less than a vaporization pressure of the refrigerant.
15. The mold assembly of claim 14 , wherein the pressure reducing device is positioned in the fluid channel.
16. The mold assembly of claim 14 , wherein the temperature control system is an open loop system.
17. The mold assembly of claim 14 , wherein the temperature control system is a closed loop system.
18. The mold assembly of claim 17 , wherein the temperature control system further comprises a heat exchange unit comprising a compressor and a condenser, the heat exchange unit being configured to receive a volume of refrigerant exiting the fluid channel, increase a pressure of the refrigerant and return the refrigerant toward the pressure reducing device.
19. The mold assembly of claim 14 , wherein the pressure reducing device comprises a valve.
20. The mold assembly of claim 19 , wherein the valve comprises a fixed diameter orifice.
21. The mold assembly of claim 19 , wherein the valve comprises a variable diameter orifice.
22. The mold assembly of claim 14 , wherein the pressure reducing device is proximate to the mold cavity.
23. The mold assembly of claim 14 , wherein the refrigerant comprises nitrogen or carbon dioxide.
24. The mold assembly of claim 14 , further comprising at least one temperature control element configured to affect a temperature of the mold section or the cavity section.
25. The mold assembly of claim 14 , further comprising a temperature sensor and a controller, the temperature sensor and the controller being configured to substantially maintain the mold assembly at a desired temperature.
26. The mold assembly of claim 14 , wherein the temperature control system further comprises a flow regulator positioned upstream of the pressure reducing device, the flow regulator being configured to selectively control a flow rate at which the refrigerant enters the pressure reducing device.