Rectangular Duct Connections

ORIGINAL 4-BOLT RECTANGULAR DUCT CONNECTIONS

The METU 4-bolt system for the easy and fast and assembly of rectangular ductwork was one of METU's main innovations which rapidly became a worldwide industry standard.

  1. The bead eases the installation of clamps.
     
  2. The supporting leg offers additional stability and, in conjunction with the sturdy corners, reduces the eventual deflection of the frame considerably.
     
  3. Also available with injected HD-sealant upon request.
     
  4. The dished internal web presses against the duct wall, acting as a metallic self-sealing lip.
     
  5. The leading edge (optional) facilitates the insertion of the duct wall into the profile.

CORNER PIECES

Very sturdy corner pieces to be inserted into the profile ends. They are made of heavy gage material and have a special shape providing extra strength to resist the important loads of the 4-bolt connection system and to minimize the necessity of clamps. Several corner pieces types have been developed to suit your needs and your rectangular duct manufacturing techniques.

Corner Pieces "A"
The original and strongest corner piece. 
The duct-wall needs to be notched out. 

 

Corner Pieces "A" with oval Hole
Same characteristics as the A-corner above, but with 
an oval hole for more flexibility during the assembly.
The duct-wall needs to be notched out. 

Corner Pieces "A" with short Legs
Corners for small duct dimensions.
The duct-wall needs to be notched out. 

 

Corner Pieces "S"
Duct-wall seam does not need to be notched out.  
Although approx. 30% weaker than the A-corners, 
they are heavy-gage press-formed and stronger than 
most corner pieces in the market.

Corner Pieces "S" with short Legs
Corners for small duct dimensions. 
Duct-wall seam does not need to be notched out.

Corner Pieces "B"
Economical corner pieces. 
Duct-wall seam does not need to be notched out.  
Approximately 40% weaker than the A-corners.

CLAMPS

Sturdy clamps made of heavy gage pressed material fitting tightly to the shape of the rectangular profile. They are designed to provide additional support by larger duct cross-sections or higher pressure loads. Available as G-Clamps, fitted with a bolt, or Drive Clamps, when installation space is restricted. (Clamp recommendations)

G-Clamps

 

Profiles are pressed together using a bolt. Flexible and easy installation. The G-Clamps are massive and designed to cope with high loads. The bolt is the same as flange bolts, that way you only need one wrench size.

Drive Clamps

 

Ideal clamp where installation space is restricted, such as when ducts are close to ceilings or walls. The clamp is slightly tapered to ease its installation. It is therefore easier to put in place than the C-shaped long clips. Thanks to its broad end-face, the drive clamp can be driven into position in confined spaces with a piece of pipe for instance.

Sturdy connections and reduced assembly times

 

Product List with Prices

Profile choice according to stability

 

Air-tightness

Installation Instructions

Texts for Tenders

Inertia Moment and Section Modulus

Stability Tests

 

High Temperature Tests

STP Documents

The four criteria of a duct flange

Original 4-Bolts Patent

Sturdy Corner Pieces

Drive Clamps Production