Norgren Collateral

One of the benefits of manifolds is reducing the number of connections compared to mounting individual components. One way to visualize this is to think of an ice cream bar with a selection of five toppings. While each could have its own dispense nozzle, it is more efficient for the ice cream eater if the five feed into one dispenser. In a valve manifold, the same effect is achieved by cross drilling - drilling holes that intersect so multiple channels lead to or from a single opening. One challenge is cross drilling is to keep the intersections free of debris or burrs caused when the drill passes through the manifold material into empty space. Just this little bit of material can get caught in a valve and cause a failure. The reliability of two identical assemblies can vary widely depending on the quality of the machining, and this impacts the overall reliability of the finished machine or instrument. A designer sourcing a manifold assembly should investigate the supplier's techniques and track record for reliability. Cross drilling is a straight forward and cost effective way to integrate multiple channels and connections into a block of metal or plastic, but it has some limitations. Holes can only be drilled in straight lines and with a single diameter, so there is a limit to the complexity and dimensionality of the design. If a more complicated (or more densely populated) manifold is required, then a multi- layer laminated plastic manifold is called for. A laminated manifold is constructed by machining the desired flow paths in layers of plastic and then bonding the layers together for the finished manifold. This process is much more flexible than drilling. It is possible to make curved channels, to change the diameter of the channel or even add contoured features like mixing or accumulation chambers right in the manifold. Increasing the number of layers accommodates more complex designs. A supplier experienced in manifold technology can help the OEM design team select the best system based on their application requirements. For example, if they can divide functions into subsets like one assembly for pneumatic motion control and another one for liquid dispensing, perhaps two cross-drilled manifolds will be adequate (and less costly). On the other hand, if they are building a portable machine where space is at a premium, they may need a single, more sophisticated laminated manifold. Manifolds allow for the internal connection of flow paths through straight or complex three dimensional channels. Manifold Construction 04 A white paper

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