Programmable computer controlled reaction injection mixing head system
AssigneeThe Upjohn Company
InventorsPeter Tilgner, Robert D. Wingard, Shirley M. Leida, Kenneth L. Erwin, Jr.
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Abstract
Progammable computer controlled reaction injection mixing of selectively variable reactive fluid polymerizable components is disclosed, embodying an improved reactive injection mixing head construction which facilitates rapid changes in mix formulations between successive pour or molding operations in a continuing succession of such operations, while maintaining consistently uniform results in the finished products.
Claims9
In a system incorporating a high pressure reaction injection mixing head for mixing selected ones of different fluid components to produce polymeric molding mixtures whose compositions may be rapidly changed between successive pour cycles in filling a series of molds, the combination of:
- separate flow paths including means for storing, transporting to said mixing head and recirculating to storage each component individually and including in each separate flow path apparatus for inducing a high pressure in that component as it enters said head during a mix/pour cycle of said head;
- programmable computer means for selectively pre-setting said high pressure and the time of flow under said pressure of each component during a mix/pour cycle, said computer including means for producing base reference signals characteristic of the respective pressure and flow time selected for each component;
- component sensing means for each component producing signals characteristic of the pressure and flow times actually occurring during the mix/pour cycle;
- comparator means producing signals responsive to any difference between the signals from said respective component sensing means and said base reference signals;
- and
- means sensitive to said comparator response to vary the output of said high pressure inducing apparatus so as to effect cancellation of said comparator response.
A system for reaction injection mixing mixtures of at least two reactive components and capable of producing polymeric molding mixtures whose compositions can be rapidly changed between successive mix/pour cycles in filling a series of molds, comprising:
- separate flow paths for each of the reactive components, each path including means for transporting from storage to a mixing head and recirculating to storage each component individually and including in each separate flow path, conduit means for transferring one component from a storage tank to a series of means including low-pressure pump means for continuously advancing said component through said conduit means, heat exchange means for heating said component, high pressure pump means for inducing a high pressure in said component for a mix/pour cycle, low-pressure by-pass means for providing a flow passage around the high pressure pump means between mix/pour cycles, and return conduit means for returning said component to storage between mix/pour cycles,
- a mixing head comprising (a) a body defining a mixing chamber open at one end to form a discharge port, (b) a control plunger making a piston fit in said mixing chamber and being reciprocable between a component recirculating position in which it occupies said chamber with a free end of said plunger substantially flush with said discharge port, and a component mix/pour position in which the free end of said plunger is retracted so as to be spaced substantially from said discharge port, (c) component passage means in said head for each component, each such means including inlet means, an injection assembly, an injection port, and outlet means, wherein said injection port opens into said mixing chamber at a point below said plunger free end when retracted, and said injector assembly is interposed between said component inlet means and said injection port and includes an injector pin and cooperating orifice means, said pin being biased normally to close said orifice but being displaceable against said bias under the influence of the component pressures induced by the low-pressure and high-pressure pump means to permit restricted flow of said component to said return conduit means under low pressure operation and substantially unrestricted flow to said mixing chamber during operation of the high pressure pump means for a mix/pour cycle,
- programmable computer means for selectively pre-setting said high pressure and the time of flow under said high pressure of each component during a mix/pour cycle, said computer including means for producing base reference signals characteristic of the respective pressure and flow time selected for each component;
- component sensing means for each component producing signals characteristic of the pressure and flow time actually occuring during the mix/pour cycle;
- comparator means for producing signals responsive to any difference between the signals from said respective component sensing means and said base reference signals;
- and
- means responsive to said comparator response to vary the output of said high pressure pump means so as to effect cancellation of said comparator response.
Dependencies are inferred from the claim text.