Joining Clips SR

SR Joining Clips
  • For the assembly of the AF, LF, BF and UF circular flanges.
  • In galvanized and stainless steel
  • Easy and rapid installation (see Nut Runner SE).
  • Available with or without gasket (PE, GF).
  • With gasket: air-tightness class C (DIN EN 12237))

In the example above the SR Joining Clip connects a duct fitted with a LF circular flange (Van Stone duct) with another duct fitted with an AF circular flange.

1.  Duct with turned out edge (Van Stone)
2.  LF Circular Flange
3.  Ducts (Spiro, welded, longitudinal seam, etc.) 
4.  AF Circular Flange
5.  Notches (see also Notching Tools)
6.  SR Joining Clip
7.  Gasket (PE, GF)
8.  Bent bolt
9.  Nut runner SE

Function of the "V" shaped SR Joining Clip


When tightening the joining clip two forces apply:

A)   An axial force pushing the flanges against one another.
B)   A radial force centering the flanges.

Here are a few good reasons for ordering joining clips with gasket:

The gasket is applied under ideal conditions in our factory (no dirt, extreme temperatures or humidity usually found on the construction site).

Labor and time savings on the construction site

Fittings such as Elbows are easier to position adjust (no friction) without damaging the gasket.

Joining clips with gasket allow an easy disassembly of ductwork segments.

The air-tightness class C / ATC3 can only be reached when using joining clips SR with gasket.

SR with PE gasket: up to approx. + 60°C
SR with GF gasket: up to approx. + 200°C

SR mit Lever


A :  ≈ 33 mm
B :  ≈ 73 mm 
C :  M6

Special version with lever for the small joining clips SR 20-45 (Duct-Ø 200 to 450 mm).

Not recommended for larger Joining Clips (Duct-Ø 500 to 900 mm), as the lever might not be able to compress the gasket sufficiently to reach the air-tightness class C.

Net additional charges upon request.


Installation Instructions

Installation Video

To be taken into consideration when fitting stainless steel parts


Texts for Tenders




CAD Drawings

Equipotential Bonding of the AF, BF, LF and UF Circular Flanges and the SR Joining Clips 

Made by METU in Germany

Air-tightness class C (DIN EN 12237)