DIN 32676

DIN 32676 relates to the food and drink processing industry and, in particular, to tri-clamp fittings. A tri clamp fitting consists of four parts, namely: two weld ferrules a seal and finally a clamping band to secure the two ferrules to each other. Tri clamp fittings have a high hygienic standard and are mainly used in the food, beverage, pharmaceutical and cosmetic industries.

Functioning of a tri clamp coupling

A tri-clamp fitting consists of two flange ends, a gasket and a clamp to secure the connection. During assembly, the seal is placed in the groove of the ferrule, which automatically retains the gasket. Then the other ferrule is placed against the existing ferrule (with seal). This ensures that the welding ferrules and seal are coaxially centred. Next, a clamping band is used to fasten the two ferrules together. By means of this connection, the gasket is deformed in such a way that no dead space can occur and a tight connection is achieved.

The tri clamp coupling is often used due to its ease of use. The tri clamp coupling is extremely popular, particularly in the American market. Of all fittings sold, 67% have a tri-clamp connection.

Examples of DIN 32676 tri clamp couplings

Tri clamp welding ferrule

Tri clamp gasket

Clamp

Tri clamp dimensions

The dimensions according to the DIN 32676 standard are divided into three size systems: DIN, INCH and ISO. In addition, the welding ferrules are available in short and long versions. In this overview the sizes are shown in millimetres.

Gaskets

There are various materials that you can use for sealing. Depending on the temperature and the medium, you can apply the right seal. The seals are available in EPDM, NBR, Silicone, Viton, PTFE and PTFE with envelope gasket. The pre-material must comply with DIN EN 10088-3 and is available with an FDA or EC1935/2004 certificate.

What exactly do you need to measure?

Suppose you are looking for a matching seal for a tri-clamp coupling. Do you know exactly what you need to measure to get the right seal? It is quite simple! You measure the internal tube size, this is the B dimension, and you measure the external flange size, this is the D dimension.

Please note: In Europe, metric measurements are used and in the United States, INCH measurements. Therefore, they do not fit together perfectly.

Certificates

As standard, these couplings are available with a 3.1 certificate. The gaskets are available with an FDA or EC1935/2004 certificate.

Pressure resistance

The following working pressures apply at a temperature of 140°C:

• Tube size 6.35 mm to 42.4 mm: 25 bar
• Tube size 48.3 mm to 76.2 mm: 16 bar
• Tube size 85.0 mm to 219.1 mm: 10 bar