1”/0.5”SMS/DS 1.4404 (AISI 316L) Sanitary Concentric Reducer Butt Weld

SMS/DS Concentric Readucer Welded

Dimensions & Sizes

Core Principles of SMS 1145 / DS 852 for Sanitary Fittings

SMS (Swedish Dairy Standard) and DS (Danish Standard) are hygienic piping system standards widely adopted in Europe, particularly in Nordic countries, for the dairy, food, and pharmaceutical industries. They are renowned for their robust clamp connection, excellent sealing performance, and high degree of interchangeability.

Core Connection: Unique Clamp System

SMS 1145: Defines the system for the clamp connection. This connection consists of grooved tube ends, a flat gasket (e.g., NBR, Silicone, EPDM), and an external multi-segment clamp. This design generates a strong axial compression force, ensuring reliable sealing and allowing for quick disassembly and assembly.

DS 852: Compatible with SMS 1145, though there might be minor differences in certain dimensions and tolerances. Together, they form a robust and versatile hygienic connection solution.

Dimensions and Tolerances

The standards strictly define the outer diameter of the tube, the dimensions of the end grooves, and the mating dimensions of the clamp. This high level of standardization ensures perfect interchangeability between tubes, fittings, and clamps from different manufacturers, providing users with significant sourcing flexibility and maintenance convenience.

Materials and Surface Finish

Materials:The standards require the use of stainless steel such as AISI 316L (1.4404) or AISI 304 (1.4301) to ensure excellent corrosion resistance.

Surface Finish: The standards require product contact surfaces to be smooth and easy to clean. The typical delivery condition is mechanical polishing, with an internal surface roughness typically required to be Ra ≤ 0.8 µm, which effectively prevents microbial adhesion.

Hygienic Design

The internal joints of the fittings (e.g., weld seams) must have a smooth transition, free of crevices and concavity. For a welded 45° elbow, the internal weld must be flush, strictly adhering to the no-dead-leg principle to meet rigorous hygienic cleaning requirements.

Gaskets

The standards specify the use of flat elastomeric gaskets. The material (e.g., EPDM, Silicone, FKM) must be compatible with the processed media and cleaning/sterilization processes (e.g., CIP/SIP).