Two stage system and method for molding containers

Patent metadata

Field	Value
Publication number	US-9987787-B2
Application number	US-201314900721-A
Country	US
Kind code	B2
Filing date	Jun 28, 2013
Priority date	Jun 28, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A method and system for hydraulic blow molding a container from a preform 24 . A molding medium is injected into the preform from a nozzle 12 during a first molding stage. In the first molding stage, the molding medium is injected so as to be specifically directed at a closed end of the preform 24 . During the first molding stage, the preform is axially stretched in response to the force exerted on the preform by the molding medium. The molding medium is also injected into the preform during a second molding stage, where the molding medium is injected at a flow rate greater than a flow rate during the first molding stage. During the second molding stage, the preform is radially expanded into the shape of the container.

First claim

We claim:

1. A method of hydraulic blow molding a container from a preform, the method comprising the steps of:
positioning a preform within a mold having surfaces defining a cavity in the shape of the container;
injecting a molding medium into the preform during a first molding stage, the molding medium being a liquid, being injected at a first flow rate and being specifically directed at a closed end of the preform;
axially stretching the preform in response to a force exerted on the closed end of the preform by the molding medium during the first molding stage;
injecting the molding medium into the preform during a second molding stage, the molding medium being injected at a second flow rate that is different from the first flow rate during the second molding stage; and
radially expanding the preform into the shape of the container during the second molding stage.

2. A method of hydraulic blow molding a container from a preform, the method comprising the steps of:
positioning a preform within a mold having surfaces defining a cavity in the shape of the container;
injecting a molding medium into the preform during a first molding stage, the molding medium being a liquid, being injected at a first flow rate and being specifically directed at a closed end of the preform;
axially stretching the preform in response to a force exerted on the closed end of the preform by the molding medium during the first molding stage;
injecting the molding medium into the preform during a second molding stage, the molding medium being injected at a second flow rate that is greater than the first flow rate during the second molding stage; and
radially expanding the preform into the shape of the container during the second molding stage.

3. A method of hydraulic blow molding a container from a preform, the method comprising the steps of:
positioning a preform within a mold having surfaces defining a cavity in the shape of the container;
injecting a molding medium into the preform during a first molding stage, the molding medium being a liquid, being injected at a first flow rate and being specifically directed at a closed end of the preform;
axially stretching the preform in response to a force exerted on the closed end of the preform by the molding medium during the first molding stage;
injecting the molding medium into the preform during a second molding stage, the molding medium being injected at a second flow rate that is different from the first flow rate during the second molding stage;
radially expanding the preform into the shape of the container during the second molding stage; and
wherein the molding medium is ejected during the first molding stage from an exit orifice having a diameter that is less than a diameter of an outlet from which the molding medium is ejected during the second stage.

4. The method of claim 1 , wherein the step of axially stretching the preform is solely initiated by the force exerted on the preform by the molding medium during the first molding stage.

5. The method of claim 1 , wherein the injecting of the molding medium during the first and second molding stages is sequential.

6. The method of claim 1 , wherein the injecting of the molding medium during the second stage molding is cumulative with the injecting of the molding medium during the first molding stage.

7. The method of claim 1 , wherein the molding medium is passed through a flow straightener prior to being injecting into the preform during the first molding stage.

8. The method of claim 1 , wherein the step of axially stretching the preform includes the step of introducing a rod into the preform and injecting the molding medium into the preform through the rod.

9. The method of claim 8 , further comprising the step of advancing the rod into the preform during the step of axially stretching the preform, and the step of continuing injecting of the molding medium into the preform as the rod is being advanced.

10. The method of claim 9 , wherein during the step of advancing the rod, the rod is prevented from contacting the preform.

11. The method of claim 8 , further comprising the step of retracting the rod prior to the step of radially expanding the preform.

12. The method of claim 8 , further comprising the step of retracting the rod during the step of radially expanding the preform.

13. The method of claim 8 , further comprising the step of extending a centering rod into the mold cavity and engaging a closed end of the preform with the centering rod.

14. The method of claim 1 , further comprising the step of extending a centering rod into the mold cavity and engaging a closed end of the preform with the centering rod.

15. The method of claim 14 , wherein the centering rod engages the closed end of the preform prior to the axially stretching step.

16. The method of claim 14 , wherein during the step of axially stretching the preform, the method further comprises the step of retracting the centering rod while maintaining the centering rod engaged with the closed end of the preform.

17. The method of claim 14 , wherein the molding medium is passed through a flow straightener prior to injecting into the preform during the first molding stage.

18. The method of claim 1 , wherein the second flow rate exhibits a second velocity and the first flow rate exhibits a first velocity, the first velocity being greater than the second velocity.

19. A molding system for hydraulic blow molding of a preform into a container, the molding system comprising:
a nozzle, the nozzle including nozzle body having a main bore extending therethrough from an inlet to an outlet, portions of the main bore defining a valve seat, the nozzle also including a seal pin received in the main bore and moveable between a closed position and an opened position, the seal pin including a sealing surface and further having a central bore extending therethrough from an entrance orifice to an exit orifice;
an actuator coupled to the seal pin and configured to move the seal pin between the closed position and the open position, in the closed position the sealing surface engaging the valve seat and closing off the main bore from the outlet, in the open position the sealing surface being spaced apart from the valve seat;
a source of molding medium, wherein the molding medium is a liquid product that is to be retained in the container, the source being the coupled to the nozzle and the molding medium being provided to the nozzle in a pressurized state; and
whereby during a first molding stage the seal pin is in the closed position and the molding medium is injected as a liquid vector into the preform from the source through the central bore and the exit orifice, and thereafter the seal pin is moved to the open position and during a second molding stage the molding medium is injected into the preform from the source through the main bore and the outlet, the exit orifice being centrally located within the outlet.

20. The molding system of claim 19 , wherein the exit orifice has a diameter that is smaller than a diameter of the outlet.

21. The molding system of claim 19 , wherein the exit orifice is coaxial with the outlet.

22. The molding system of claim 19 , wherein the exit orifice is formed within a nipple on a distal end of the seal pin, the nipple extending into the outlet when the seal pin is in the closed position.

23. The molding system of claim 22 , wherein the nipple sealingly engages the outlet when the s

Assignees

• Discma Ag

Inventors

• Lisch G David
• Beuerle Frederick C
• Eberle Theodore F
• Maki Kirk E

Classifications

• B29L2031/7158

  Bottles · CPC title

• B29C2049/465

  being incompressible · CPC title

• B29C49/4289

  Valve constructions or configurations, e.g. arranged to reduce blowing fluid consumption · CPC title

• B29C49/783

  blowing pressure · CPC title

• B29L2022/00

  Hollow articles (tubular articles B29L2023/00; pneumatic tyres B29L2030/00) · CPC title