Overcollars MU

MU Overcollars

An economical connection for duct diameters from 71 to 315 mm

  1. Duct wall
  2. Rohrmuffe MU Overcollar
  3. Gaskets made of polyethylene foam PE, vitreous fibers GF and EPDM

A = ≈ 90 mm
B = ≈ 4,2 mm

For inner-duct diameters from 71 up to 315 mm.
CAUTION: Diameters above 315 mm only suitable for very sturdy ducts. Tightness and stability cannot be guaranteed.

Suitable duct types: spirally wound ducts, longitudinal seam ducts and fittings.

Not suitable for ducts and fittings with turned-out edges and ducts with stiffening ribs.

Fixations: no screws, rivets or spot-welds are necessary!


The unique Allen screw (M6) to be tightened shortens the assembly times drastically. Easy disassembly (unlike the plug-in system).


Diameter differences of up to 4 mm are bridged.


Air-tightness class D (DIN EN 12237) or ATC 2 (DIN EN 16798-3) when installed correctly.


Hardly any protrusions inside the duct (ideal for the extraction of chips, fibers, etc.).

No additional measures, such as the use of adhesive tape or sealant, are necessary.

Equipotential bonding by correct installation (must always to be verified).



MU with PE gasket: up to approx. + 100°C
MU with GF gasket: up to approx. + 200°C

On a 100 mm Ø plain duct the necessary force to pull the connection apart is ≈ 1100 N (humidity and dirt can negatively affect these values). When installed vertically, each duct segment must be individually fixed and secured.

Does not provide additional stability or stiffness to the duct, especially under negative pressures:
+ 3000 Pa: Rohr-Ø 71 - 315 mm
- 2000 Pa: Rohr-Ø 71 - 150 mm
- 1000 Pa: Rohr-Ø 71 - 315 mm



Installation Instructions


Installation Video

To be taken into consideration when fitting stainless steel parts


Texts for Tenders

STP Documents

Possible Packing


Made by METU in Germany