The most common hygienic couplings are DIN 11851couplings, SMS couplings, Triclover (Tri-clamp) couplings, RJT couplings, IDF couplings, Macon couplings.

Pharmaceutical and food industries are the most popular sectors. Because of ease of installation and “cleanliness” of the connection, they are also used in the chemical industry.

Fittings with a serrated hose tail (used on rubber hoses) can be installed with safety clamps or crimped with ferrules, while fittings with a smooth hose tail (used on rubber and thermoplastic hoses) are mounted with safety clamps.

For weld-in couplings, you should measure the flange plate diameter at its widest point, bore diameter and wall thickness. For couplings with a hose tail, in addition to the diameter of the flange plate and bore, the diameter of the hose tail measured on the outside, at its widest point, is very important. This measurement helps to identify to which standard the coupling was made, and reduces the risk of error by choosing a wrong coupling.

If two couplings made to different standards are not properly connected to each other, it may cause dead zones in the gaps due to the difference in inner diameters. This results in the accumulation of medium, which can lead to the growth of bacteria and microorganisms.

Everything depends on the clamp used and the quality of (welded) connection. A basic clamp is suitable for 25-15 bar pressure, depending on the size of the couplings, although there are clamps that can withstand 75 bar.

Triclover couplings may have different dimensions (inner diameter and flange diameter) due to the different standards to which they are made. There are 3 main standards: DIN-A (DIN 32676), DIN-B (ISO 1127) and DIN-C (ASME BPE).