What are Dairy Valves, Fittings, and Tubes?
Updated: Apr 19
Dairy valves, fittings and tubing, also known as hygienic valves fittings and tubing, were created and used mainly because they are cleanable, either by dismantling a pipe line and cleaning it manually or using a CIP (clean in place) system.
Sanitary fittings and valves do not contain pockets, threading, or tight bends to prevent areas that are difficult to clean. This limits entrapment areas where bacteria could harbor.
Dairy valves such as the sanitary diaphragm valve often come in zero dead leg designs to prevent accumulation of bacteria.
Stainless steel is used to create dairy valves, fittings and tubes to resist corrosion. Two different alloys, 304 and 316 are used, they both contain a mix of elements such as chromium, nickel, carbon, and manganese.
304 is the most commonly used sanitary alloy, and is known for its appearance, durability, and corrosion resistance. 316 has an extra element, molybdenum, turning it into an even more corrosion resistant material to withstand tougher environments involving industrial solvents, acidic material, highly saline conditions.
Food grade rubber such as Silicone, NBR, VITON, are used to manufacture sanitary gaskets and dairy hoses. This makes sure they are flexible and can handle demanding environments.
Surface Finish and Roughness Average (Ra)
Dairy valves, fittings, and tubes are mostly distinguished by its surface finish, commonly known as Roughness Average. When viewed through the lens of a microscope, the surface of stainless steel has peaks and valleys that can harbor bacteria during the production cycle.
Sanitary Tubes are polished to the extent where the peaks and valleys are minimized or even eliminated. A lower roughness average will mean a smoother surface.
Sanitary fittings which are made from sanitary pipes will have a standard roughness average of 32 Ra. Bio-Pharmaceutical tubes and fittings will have a surface finish of as low as 15 Ra.
Assembling Dairy Tubes, Fittings, and Valves
Sanitary tube fittings are connected to each other by butt welding, ferrule connections, or threaded connections such as SMS and DIN threads.
Butt welding is the most straight forward method but prevents disassembling in future. Ferrule connections are assembled by connecting two tri clamp ferrules with a gasket and clamp ring that can be disassembled easily by hand. Male and female threaded connections have to be disassembled by a spanner but can accommodate slightly higher pressure.
NKE is a supplier of Dairy Valves, Fittings, and Tubes. Contact us to know more.