In the ball valve design, some manufacturers have attempted to eliminate the dead space by inserting plastic shims (PTFE fillers) around the ball
(PRWEB UK) 7 February 2012
It has recently been found that some fluid handling products being sold as sanitary are not as clean as consumers would think states Keith Davies of Action-Sealtite. Whether it is a small‐scale lab, medium sized batch processor, or large manufacturer, the right dry‐disconnect coupling is critical– with full support and validation from start to finish.
Beware. There are many so called “sanitary” dry break couplings on the market today. But most of them have unpolished internal finish that is unacceptable in sanitary applications. These dry break couplings are usually based on poppet valve or ball valve designs. By nature, these couplings are not sanitary because they can trap liquid and allow bacteria to germinate. A poppet valve will always contain a dead volume of liquid, no matter what, and a ball valve design allows a dead space between the ball and the body. In the ball valve design, some manufacturers have attempted to eliminate the dead space by inserting plastic shims (PTFE fillers) around the ball. The problem with fillers is that it cannot be guaranteed 100% if the dead space has been completely filled. It would be impossible to determine the exact thickness required for the filler because of variations in the cast body and ball dimensions.Trying to assemble the body using a slightly thicker filler, the coupling will jam and make it impossible to turn the handle. If the filler is slightly thinner, then certainly there would be a small void around the ball – enough for the liquid to seep into the void and create a dead volume for bacteria to germinate.
Dry Link sanitary polished couplings from Action-Sealtite in sizes 1/2" through 4" are the only true sanitary, high‐purity, drip‐free couplings available today because of their simple butterfly design. The smooth mirror polished bore has no voids, dead spaces, crevices, or fillers that could trap bacteria. Easily drainable and sanitized using steam or other methods such as CIP, SIP, etc, our sanitary couplings are routinely specified in pharmaceutical, biotech, semiconductor, food, and cosmetic industries where ultra cleanliness is required.
Dry Link sanitary couplings are usually specified with wetted internal components polished to 20 RA micro‐inch mirror finish, although we also offer unpolished internals at economy prices. Wide choice of sizes, body & seal materials, end connections and with full material test certifications (MTR), FDA & USP certifications are available. Other options such as extra fine inside polish, electro‐polish, and outside polish to matte finish. We also offer keyed sanitary couplings for preventing accidental cross‐contamination of fluids. More information is available regarding this item from http://www.actionsealtite.com