Calibrating Mandrel Vacuum Grooves for Double-Walled Pipe Manufacturing
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Solution Overview
Problem
Existing devices for producing double-walled composite pipes face imprecise vacuum control in the transition area between the pipe and socket sections, leading to defects on the inner wall.
Innovation Solution
The calibrating mandrel features axially narrow vacuum grooves that are evenly spaced, connected to a vacuum control valve device with a control disk and pneumatic cylinder, allowing precise control of vacuum pressure through programmable logic controller-driven stepwise operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the calibrating mandrel uses traditional negative pressure areas with axially spaced feed grooves, then the vacuum control can be simplified, but the vacuum control precision in the transition area deteriorates
Solution Approach 1:
The calibrating mandrel is divided into multiple axially spaced vacuum zones, each with its own feed grooves and distribution grooves. This segmentation allows independent vacuum control in different axial regions, enabling precise control in transition areas while maintaining system simplicity through modular design.
Solution Approach 2:
Different axial regions of the calibrating mandrel are equipped with different vacuum control characteristics. The transition area receives enhanced vacuum control precision through localized feed groove positioning, while other regions use standard spacing, optimizing overall performance without uniform complexity throughout.
2Reliability
If the vacuum grooves are made wider axially, then the vacuum source can be larger and more powerful, but the energy consumption increases
Solution Approach 1:
Instead of applying vacuum uniformly across the entire calibrating mandrel surface, the system uses narrow axially spaced vacuum grooves that apply vacuum only to specific critical regions. This partial action approach maintains sufficient vacuum reliability in transition areas while minimizing the total vacuum source size and energy consumption.
Solution Approach 2:
The axial width parameter of vacuum grooves is optimized to narrow dimensions, while the axial spacing between grooves is carefully controlled. This parameter change creates an efficient vacuum distribution pattern that maintains reliability through strategic positioning rather than through increased groove width or vacuum source power.
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 enables precise pressure application with or without vacuum in the transition areas, reducing defects and improving the production quality of double-walled composite pipes.
Implementation Method 1
a calibrating mandrel protrudes into the mold tunnel for the smooth inner wall, on the outer lateral surface g econtrols a vacuum can be applied
Data Source
Figure 1~2
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Figure 5~6
AI summary
A device for manufacturing double-walled composite pipes is described, the pipes having an outer wall with crests and troughs and a smooth inner wall. The device (10) has two rows of forming jaw halves (12, 14) that form a forming tunnel (16) along a common forming section for manufacturing the composite pipe. At least one pair of the opposing forming jaw halves (14) in the forming section (16) has an inner contour (22) forming a pipe socket section (50). The remaining forming jaw halves (12) are alternately formed with transverse grooves (18) and transverse ribs (20). A calibration mandrel (24) projects into the forming tunnel (16) for the smooth inner wall of the composite pipe. Narrow vacuum grooves (26) are formed axially spaced apart on the outer surface (28) of the mandrel.A vacuum control valve device (30) is provided to close and reopen the vacuum grooves (26) located in the pipe socket section (50) in a stepwise defined manner using a drive device (38) and to connect them fluidically to a vacuum source (32).