Design hygienic process systems: six union types compared

Design hygienic process systems: six union types compared

 

 

 

 

 

 

Hygienic coupling unions

 

Connecting parts that are intended for hygienic process systems, such as in dairy and food, for example, require extra attention because these are the places where bacteria could get a chance.

This is why special hygienic couplings have been developed that prevent spaces in the pipe system where bacteria can nest.

Hygienic couplings are always made of stainless steel, with parts that come into contact with the product usually made of 316 grade stainless steel.

Below you will find the 6 most commonly used types and their applications.

 

 

1. Tri clamp connections

 

You can actually find the tri clamp connection in every standard for hygienic piping. In the ASME-BPE standard it is even the only approved connection method besides the weld connection of course

It is therefore the best possible way to quickly assemble and disassemble a pipe section for cleaning work. You don't even need any tools because a triclamp coupling can be tightened manually.

It is also a very reliable connection technique that rarely causes problems when used correctly. At 21°C, a tri clamp can withstand a pressure of more than 10 Bar and is suitable for almost all hygienic process systems.

What distinguishes this coupling most is the lack of male and female parts. With a triclamp connection, 2 identical liners are used. This makes all parts interchangeable and connectable to each other.

In short: if you have to regularly disassemble a pipe section or if you simply want to change your system, the tri clamp is the best coupling for the job.

 

Industries:
■ Dairy
■ Breweries
■ Cosmetics
■ Chemicals
■ Food and beverage
■ Pharmacy
​■ Biotech

Available for tube standards:

  • DIN 11850
  • ASME BPE
  • BS 4825-1
  • ISO 2037
  • ISO 1127

Triclamp_coupling-specifications-3D_CAD_Files_3B

Tri clamp parts:

- Two identical ferrules
- A hinged clamp
- A seal ring

Triclamp_coupling-specifications-3D_CAD_Files_1B

Triclamp_coupling-specifications-3D_CAD_Files_2B
Triclamp_coupling-specifications-3D_CAD_Files_4B

>> Download Tri clamp 3D CAD Files ASME-BPE

>> Download Tri clamp 3D CAD Files BS4825

>> Download Tri clamp 3D CAD Files DIN


 

2. DIN 11851 unions

DIN 11851 is the German standard for four part hygienic unions.

In western European countries, DIN11851 is the coupling most often used in the dairy industry. It is therefore also called "milk coupling" or "dairy coupling" and an engineer immediately knows that it concerns the DIN11851 coupling version.

These types of unions are used in product lines that require regulary assembling and disassembling.
Normally the wetted parts are supplied in 316L stainless steel and the nuts are grade 304.

DIN 11851 unions are used extensively in Germany, but also  throughout Europe and in the Middle East.

 

Industries:
​■ Dairy
■ Breweries
■ Cosmetics
■ Chemicals
■ Food and beverage
■ Pharmacy
​■ Biotech

 

For (tube) standards:
■ DIN 11850

DIN11851_Unions-specifications-3D_CAD_Files_1A

Parts:
■ A male threaded part
■ A liner
■ A round slotted nut
​■ A D-section seal

DIN11851_Unions-specifications-3D_CAD_Files_2A


>> Download DIN 11851 Unions 3D CAD Files

 

3. SMS unions

 
SMS (Swedish Manufacturing Standard) unions ​are also four parts unions with a round swivel nut, just like the DIN 11851 unions.
But there are some major differences:
  DIN11851 SMS
Female part Conical face Flat face
Male part Deep seal Turned up seal
Seal D-Shape Square shape
Working pressure 25 bar (362 PSI) 6 bar (87 PSI)

 

In general, SMS couplings are available in the same countries as the DIN 11850 couplings.

 

Industries:
​■ Dairy
■ Breweries
■ Cosmetics
■ Chemicals
■ Food and beverage
■ Pharmacy
​■ Biotech

 

Available for tube standards:
■ BS 4825
■ ISO 2037

SMS_Union_coupling-specifications-3D_CAD_Files_4A

SMS union parts:
- Male threaded part
- Square shape seal
- Liner
​- Round slotted nut

SMS_Union_coupling-specifications-3D_CAD_Files_5A

SMS_Union_coupling-specifications-3D_CAD_Files_2A

SMS_Union_coupling-specifications-3D_CAD_Files_3A


>> Download SMS Unions 3D CAD Files BS4825

 

4. RJT unions

 

RJT (Ring Joint Type) unions are the most popular hygienic connection type in the UK, but they are also used in other countries.

 

Industries:
■ Dairy
■ Breweries
■ Cosmetics
■ Chemicals
■ Food and beverage
■ Pharmacy
​■ Biotech

 

For tube standards:
■ BS 4825
■ ISO 2037

RJT_Union_coupling-specifications-3D_CAD_Files_1A

Parts:
■ A male threaded part
■ A pressed liner
■ A hexagon nut
​■ An O-shape seal

RJT_Union_coupling-specifications-3D_CAD_Files_2A

RJT_Union_coupling-specifications-3D_CAD_Files_3A

RJT_Union_coupling-specifications-3D_CAD_Files_4A


>> Download RJT Unions 3D CAD Files BS4825

 

5. IDF unions

IDF_Union_coupling-specifications-3D_CAD_Files_1A

 

IDF_Union_coupling-specifications-3D_CAD_Files_2A

 

IDF_Union_coupling-specifications-3D_CAD_Files_3A

IDF_Union_coupling-specifications-3D_CAD_Files_4A


>> Download IDF Unions 3D CAD Files BS4825

 

6. Flanged connections

DIN11853_flanges-specifications-3D_CAD_Files_1A