Application, Installation And Maintenance Of Sanitary Stainless Steel Aseptic Din11864-1 Connectors

A sanitary stainless steel aseptic DIN11864-1 union (SS316L, weld, -20°C to 120°C, 0-10 bar) seals pharma and biotech lines without dead legs. Its O-ring sits in a machined groove while metal centering controls compression, so no crevice traps product or bacteria. That design keeps the seal face smooth and cleanable.

How the Seal Prevents Cross Contamination

O-Ring Groove Plus Metal Centering

The din11864 design places the O-ring in a machined groove. A metal shoulder limits compression when parts meet.

• 🔹 Machined groove holds O-ring in place

• 🔹 Metal shoulder controls compression depth

• 🔹 Smooth face leaves no retention zone

• 🔹 Seal stays fixed under pressure swings

The sealing face stays smooth and continuous. No gap remains where material collects. Clean-in-place and steam-in-place fluids reach the full seal area.

Three Connection Forms in the Standard

The din11864 standard covers three parts with the same sealing principle. The din 11864 1 form uses threads, din 11864 2 uses flanges, and din 11864 3 uses clamps.

Each form uses the same Form A groove. Switching connection style at any node keeps seal performance consistent across the system.

Material and Surface Requirements

Wetted parts use 316L stainless (1.4435 or 1.4404). Ferrite content is controlled to protect weld zones from corrosion.

Internal roughness reaches Ra < 0.8 μm for standard service. Higher-grade duty calls for Ra < 0.4 μm. Smooth surfaces reduce microbial attachment.

O-ring compounds include EPDM, PTFE, and FFKM. EPDM suits steam sterilization, PTFE handles aggressive chemistry, and FFKM covers high temperature with corrosive media.

Pressure and Temperature Limits

DIN 11864-1 unions carry pressure ratings by bore size. Small bores from 12.7 mm to 41.0 mm rate at 4.0 MPa. Larger bores from 42.4 mm to 104.0 mm rate at 2.5 MPa.

Working temperature depends on the O-ring compound. Standard elastomers cover -20°C to 120°C. Confirm sterilization temperature against the seal rating before selection.

Installation and Maintenance Steps

Correct assembly decides seal reliability. Check the O-ring and clean the metal centering face before closing the joint.

1. Inspect the O-ring for cuts or deformation.

2. Clean the metal centering face of particle residue.

3. Seat the O-ring in the machined groove.

4. Tighten by hand until metal faces touch.

5. Check O-ring compression set at service intervals.

Metal-to-metal contact sets the design compression. Extra torque adds no seal benefit and can damage the groove edge.

Frequently Asked Questions

How does DIN 11864-1 differ from DIN 11851?
DIN 11851 is a legacy milk union with a seal gap. DIN 11864-1 uses a machined groove and metal centering to remove dead space.

Can the three connection forms be mixed?
Yes. The din 11864 1, din 11864 2, and din 11864 3 share the same sealing face, so a system can switch forms at any node.

How often should the O-ring be replaced?
It depends on sterilization cycles and temperature. Replace it when compression set or surface cracks appear.

Which industries use this union?
Pharmaceutical, biotechnology, food, and chemical lines that demand aseptic operation.

Can the union work under vacuum?
Yes. Metal centering holds the O-ring in place under positive or negative pressure, so the seal face does not shift.

DIN 11864-1 Aseptic Union

• DIN11864 aseptic fittings meet the exacting needs of food, chemical and pharmaceutical industries.
• Available with optional lengths to suit Orbital and Manual Welding, these unions have been designed to match tube and pipe specifications in DIN 11850; ISO 2037, ASME BPE 2002 and BS 4825 Part 1 and also ISO 1127 for schedule pipe.
• DIN11864-1 union consists of four parts: Nut, Male, Liner and Gasket.

Technical Data

Product Parameter