Injector for Liquid Formulation Injection into Molten Polymer
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Solution Overview
Problem
The existing injection apparatus for liquid formulations into molten polymeric materials faces issues with blockages due to temperature gradients, leading to downtime and lost production, as dyes sublime or pigments melt, causing conduit blockages, which requires disconnection and cleaning of the injector, resulting in significant production losses.
Innovation Solution
A method and apparatus that allow the injector to be reconfigured to disengage from the polymer flow conduit while maintaining polymer flow, enabling continuous operation and allowing for cleaning or replacement of the injector without stopping the extrusion process, using movable sections and injectors to ensure uninterrupted polymer flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the injector is directly connected to the extruder to inject liquid formulation into molten polymer, then the liquid formulation can be injected at high pressure, but temperature gradient causes dyes to sublime and pigments to melt, leading to conduit blockages
Solution Approach 1:
The system is divided into separate functional sections: a heating section that receives molten polymer from the extruder, and a injection section that contains the injector and conduit for liquid formulation. This segmentation isolates the temperature-sensitive injection conduit from the high-temperature polymer flow, preventing blockages while maintaining injection capability.
Solution Approach 2:
Molten polymer acts as an intermediary medium that transfers heat from the extruder to the heating section, which then selectively heats the liquid formulation for injection. This intermediary approach allows controlled thermal transfer without directly exposing the injection conduit to high temperatures that would cause blockages.
2Ease of repair
If the injector is disconnected from the extruder for cleaning, then the conduit blockage can be removed, but the extrusion process must be stopped, resulting in significant production losses
Solution Approach 1:
The injector assembly is designed as a separable component that can be disconnected from the extruder for cleaning while the extrusion process continues in the heating section. This modular segmentation allows maintenance of the injection system without interrupting the overall production process.
Solution Approach 2:
The system includes preliminary blockage detection capabilities that alert operators before complete blockage occurs, allowing scheduled cleaning during planned maintenance windows rather than unexpected shutdowns. This preliminary action minimizes disruption to production continuity.
3Measurement precision
If the liquid formulation is held in the conduit for extended time prior to injection, then the injection can be precisely timed, but the formulation may thicken due to dye sublimation, increasing blockage risk
Solution Approach 1:
The conduit system incorporates localized heating zones that maintain optimal temperature only in specific sections where liquid formulation is held or flowing. This local quality approach prevents dye sublimation and formulation thickening in storage sections while allowing precise injection timing control.
Solution Approach 2:
The system dynamically adjusts temperature parameters in different conduit sections based on formulation residence time. Sections with longer hold times receive enhanced heating to prevent thickening, while sections with rapid flow maintain lower temperatures to preserve formulation properties and enable precise injection timing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution minimizes downtime and production losses by allowing continuous operation of the extrusion process during injector maintenance or cleaning, ensuring that downstream processes like fiber or sheet formation can continue uninterrupted.
Implementation Method 1
Heat is conducted from the extruder and/or molten polymeric material contained therein to the outlet of the injector and, in turn, heat is conducted along the conduit of the injector towards its inlet
Implementation Method 2
some dyes may sublime during passage through the conduit and/or in the event that the liquid formulation is held in the conduit of the injector for an extended time
Implementation Method 3
some pigments used in liquid formulations may melt as the temperature to which they are subjected increases as the formulation moves towards the outlet of the conduit
Data Source
AI summary
Injector (14) for injecting a liquid formulation into a molten polymer includes outlet (21) at one end and, at its other end, is arranged to be connected to upstream conduit (25) via a coupling housing (26) so that liquid formulation can pass from conduit into the injector, and further includes an elongate conduit (27) in which an elongate pin is slideably arranged being capable of expelling all liquid formulation from conduit. To address the risk the outlet could become blocked in use, whilst avoiding the need to depressurize and/or stop the flow or polymer in extruder (19), the injection apparatus includes a spool (34) which is rotatably mounted within wall (35) of the extruder and is arranged to be rotated about an axis which extends substantially perpendicularly to the elongate extent of the extruder through which a polymer stream (18) flows. The spool may be moved between a first configuration and a second configuration wherein a flow path is interrupted, but wherein molten polymer continues to flow in said polymer flow conduit.