Method and apparatus for thermally controlling a mold, die, or injection barrel
First Claim
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1. A method of controlling a thermal exchange liquid as it is circulated through an injection mold, die, or barrel (herein referred to as a “
- process”
), the method comprising;
establishing an energy set point, the energy set point being a desired rate of thermal energy exchange with the process;
circulating the thermal exchange liquid through the process at a selected flow rate using a positive displacement pump coupled to a motor having a programmable and controllable speed which is independent of variations in line voltage;
sensing an actual process inlet temperature and an actual process outlet temperature for the thermal exchange liquid;
determining an actual flow rate of the thermal exchange liquid;
computing an actual rate of thermal energy exchange between the thermal exchange liquid and the process according to the actual inlet and outlet temperatures and the actual flow rate; and
computing and making an adjustment to the selected flow rate so as to correct the actual rate of thermal energy exchange to the energy set point.
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Abstract
A method and apparatus are disclosed for managing thermal energy transfer between a mold, die or cavity and a thermal transfer fluid. The thermal energy being exchanged with the mold, die or cavity is calculated in real time as a function of the temperature differential between inlet and outlet fluid temperatures, the volumetric rate of fluid delivery, and known characteristics of the fluid. The rate of thermal energy exchange is controlled by varying the fluid delivery rate in accordance with a desired thermal energy exchange profile.
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Citations
14 Claims
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1. A method of controlling a thermal exchange liquid as it is circulated through an injection mold, die, or barrel (herein referred to as a “
- process”
), the method comprising;establishing an energy set point, the energy set point being a desired rate of thermal energy exchange with the process; circulating the thermal exchange liquid through the process at a selected flow rate using a positive displacement pump coupled to a motor having a programmable and controllable speed which is independent of variations in line voltage; sensing an actual process inlet temperature and an actual process outlet temperature for the thermal exchange liquid; determining an actual flow rate of the thermal exchange liquid; computing an actual rate of thermal energy exchange between the thermal exchange liquid and the process according to the actual inlet and outlet temperatures and the actual flow rate; and computing and making an adjustment to the selected flow rate so as to correct the actual rate of thermal energy exchange to the energy set point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- process”
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13. A system for controlling a rate of thermal energy exchange between a thermal exchange liquid and a process comprising an injection mold, die, or barrel as the thermal exchange liquid is circulated through the process, the system comprising:
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a process comprising a mold, die, or barrel; a positive displacement pump coupled to a motor having a programmable and controllable speed which is independent of variations in line voltage, the positive displacement pump being in liquid communication with the process and being able to circulate the thermal exchange liquid through the process at a selected flow rate; a flow rate determining mechanism for determining an actual flow rate of the thermal exchange liquid; inlet and outlet temperature sensors which are able to determine an actual process inlet temperature and an actual process outlet temperature respectively for the thermal exchange liquid; and an energy exchange controller which computes an actual rate of thermal energy exchange between the thermal exchange fluid and the process according to the actual process inlet and outlet temperatures and the actual flow rate of the thermal exchange liquid, establishes an energy set point, and computes and makes an adjustment to the selected flow rate so as to correct the actual rate of thermal energy exchange to the energy set point, the energy set point being a desired rate of thermal energy exchange.
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14. A method of controlling a thermal exchange liquid as it is circulated through an injection mold, die, or barrel (herein referred to as a “
- process”
) comprising;establishing an energy set point, the energy set point being a desired rate of thermal energy exchange with the process; circulating the thermal exchange liquid through the process at a selected flow rate using a positive displacement pump coupled to a motor having a programmable and controllable speed which is independent of variations in line voltage; determining a process inlet temperature set point for the thermal exchange liquid; controlling an actual process inlet temperature of the thermal exchange liquid so as to minimize its deviation from the process inlet temperature set point; sensing an actual process inlet temperature and an actual process outlet temperature for the thermal exchange liquid; determining an actual flow rate of the thermal exchange fluid; computing an actual rate of thermal energy exchange between the thermal exchange fluid and the process according to the actual inlet and outlet temperatures and the actual flow rate; and computing and making an adjustment to at least one of the selected flow rate and the process inlet temperature set point so as to correct the actual rate of thermal energy delivery to the energy set point.
- process”
Specification