How to Tri-Clamps

Details good to know about sanitary couplings

Tri-Clamp refer to several industry standards for metal parts! Of which a few is mentioned here (ISO-1127 from 1996, DIN-32676, BS-4825, ASME BPE 2009).

Tri-Clamp is a widely used stainless steel tube coupling standard designed and manufactured for the Food & Beverage industry. Tri-Clamp became the brand since 1919 best known from Tri-Clover-Machine Co. in USA. As USA never converted to metric units we are all stocked with old fashion imperial units! To make it all more confusing the US Tri-Clamp 3/4" size do NOT refer to the flange diameter or the inner bore – but to the outside hose diameter one could fit … a long time ago!

Sanitary single-use (Tri-Clamps) and gaskets exists from few manufactures and a variety of suppliers. Practical range used in the biotech industry is 1/2" to 8". Tri-Clamp's exist is many many more designs both industry standard and non-standard.

Above shown a bunch of clamps originating from several manufactures.

Smallest plastic Tri-Clamp connection used on HFF is well known as 3/4" size. Depending on number of HFF straws, lumen the open inner diameter (ID) varies between 9.5 mm and 15.6 mm. In other words - various 3/4" plastic Tri-Clamp's have identical outer flange dimensions (OD ~25 mm – 0.984”), but the inside bore may be different. Important when selecting, mixing couplings, seals …

The shown 2 plastic 3/4" size Tri-Clamp HFF ends - in total have 3 different inner diameters (ID)! For even more confusion the sketches illustrate that 2 flange sizes cover a range of 4 or more inner diameters! So be careful how you connect parts!

Gaskets come in a range of material choices - EPDM, PFTE, BUNA N, FKM Fluoroelastomer, Silicone ..... for bio tech application transparent platinum cured Silicone is most commonly used.

Intellectual-Property-Rights (IPR) is very comprehensive ……. here a few is mentioned:

  • Tri-Clover® and Tri-Clamp® words, names are in US a registered trademark's specific for metal parts, metal fittings owned by Alfa Laval. But as to such not covering Tri-Clamp's fabricated from plastics!
  • Tube or Pipe Clamp” covered by patent US 9151420B2, US 2013/0249212 of Engineered Products Supply, NJ, USA
  • Multi-segmented, articulating clamp” covered by patent US 8,028,378 of Sanisure Inc, CA, USA
  • Tube Clamp” covered by patent US 6,708,377 of Bio Pure Technology Ltd, England