Modern Manufacturing of Pre-Insulated Ductwork: Techniques and Innovations-2

Modern Manufacturing of Pre-Insulated Ductwork: Techniques and Innovations-2

1. The Panel-Based Flat-Pack System

This innovative method, exemplified by systems like PanelDuct, produces rigid, rectangular ducts in a flat-panel format for easy shipping and assembly.

*   Process Overview: The core of the panel is typically a metal sheet. A layer of insulation material, such as polyurethane foam, is permanently bonded to it. This laminate is then cut and sized. The panels are designed with integrated flanges and compression seals on their edges.

*   Key Manufacturing Insight: The flat-panel design is fundamental to its efficiency. It allows for continuous, optimized production lines where operations like foaming and pressing are performed by dedicated staff in a work-balanced manner. Panels can be pre-manufactured and built to stock, eliminating fabrication wait time.

*   On-Site Transformation: On the construction site, these flat panels are assembled into three-dimensional rectangular ducts. The integrated flanges and seals connect to form an exceptionally airtight system directly, without any additional sealing steps.

2. Injected Foam for Rigid Ducting

This technique creates a rigid, doubly-walled duct with a solid insulation core and is well-suited for both circular and rectangular sections.

*   Process Overview:

    1.  Form Inner and Outer Ducts: Separate inner and outer metal sleeves are fabricated. The inner duct is typically longer, with connection flanges at each end. The outer duct has a larger cross-sectional area but is shorter in length.

    2.  Assemble the Annulus: The inner duct is centered inside the outer duct, creating a precise annular space between them. In some advanced methods, a molding apparatus forms this annulus around a continuously moving pipe.

    3.  Inject and Cure Foam: A fluidized insulating material, usually closed-cell polyurethane foam, is injected into the annular space. The foam expands to fill the cavity completely and then cures into a solid, high-R-value core that also structurally bonds the two metal sleeves.

*   Technical Detail: The difference in length between the inner and outer ducts is critical. It leaves a portion of the inner duct protruding, allowing installers to easily connect inner ducts from adjacent segments with standard fasteners or clips, while the outer ducts and foam cores butt together cleanly.