Expansion joint – BDI Model C Fabric EJ

DUCTING EXPANSION JOINTS

Bachmann Dampjoint Model “C” fabric expansion joint is a general purpose flexible connector offering the convenience of metallic attachment flanges with a belted type flexible element.

When vertical, horizontal & lateral movement are present

Rugged metallic flanges allow the choice of either welded or bolted installation. Since the flanges are designed for a lifetime of service, welded installation, which eliminates all bolt holes and gasket seepage problems, becomes very practical.

  • Economical
  • Low cost installation welded or bolted
  • Easy fabric replacement
  • Minimal spring rates
  • Noise reduction
  • Vibration isolation
  • Rectangular, square or round configuration
  • Optimized utilization of fabric element

The model “C” expansion joint is Bachmann Dampjoint’s general purpose fabric expansion joint for low to moderate service temperatures. Depending on the material selected, continuous operating temperatures up to 600°F can be tolerated without the necessity of insulating layers or liners. Multi-layered type flexible element can also be used to achieve higher operating temperature. Contact Bachmann factory directly for additional details concerning your specific application.

The model “C”  expansion joint in its basic form consists of two rugged, angle-shaped flanges; an elastomeric or multi-layered, belted-type, flexible fabric element; and channel shaped, fabric clamping bars. The metallic angle flanges may be punched with a few widely spaced holes suitable for alignment purposes during welded installation, or a closely spaced pattern to match duct flanges for bolted
installation.

The flexible element may be internally or externally mounted on the angle frames depending on accessibility for maintenance. Internal fabric mounting allows future fabric repair or replacement from inside the ductwork; a feature which eliminates costly staging requirements for elevated, hard to reach expansion joints locations.

For moderately abrasive applications, the significant abrasion resistance of the reinforced rubber flexible element allows the use of a belted element without need for flow liners. The fabric element can have a 2-3” set-back from the gas stream which further contends with any moderately abrasive applications. Without liners, any particle which falls out of the gas stream into the expansion joint area is unrestricted, and hence is automatically forced back into the gas stream during thermal movement of the expansion joint element and by vortexing of flow in the area. The avoidance of flow liners also eliminates the resultant cavity which must be isolated from dust laden media. The addition of a liner in turn allows the use of multi-layered fabric elements for higher temperature applications.

(Note: To avoid insulation “picking”, Bachmann Dampjoint design philosophy dictates that composite fabrics with insulation layers must never be used against a gas stream without a flow liner. Also see model “A”)