What does “hold-down” mean in a sentence (in the context of catalysts)?
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The catalyst bed consists of a supporting layer of alumina balls, a layer of catalyst, and a hold-down layer of alumina balls. The hold-down layer is meant to press down on the catalyst in order to hold it in place; does anyone with expertise know what its proper technical name is? This post was last edited by beileim1 on 2009-2-26 09:38.]
It has been discussed at http://bbs.hcbbs.com/viewthread.php?tid=334814&highlight=hold%2Bdown.
It is stated here that the catalytic reactor has three layers: the bottom layer consists of inert aluminum and ceramic particles that provide support; the middle layer contains the catalyst particles; and the top layer of inert particles serves as a retention layer. So “hold down” means to suppress, to prevent the catalyst from being blown away; it can also be described as retaining it in place. This post was last edited by ghhan on 2009-2-26 09:35]
\"Pressing cap\" is a more appropriate translation
Hold-down shouldn’t be considered a physical object: lol. The actual objects in question are alumina balls; it can be translated as “to press down, to hold firmly in place”. Referring to the hold-down layer as a “covering layer” makes it easier to understand. Typically, a reactor (or catalyst) bed consists of inert alumina ceramic balls at the bottom, which serve primarily as a support structure; a catalyst layer is located in the middle, and one or more layers of inert alumina ceramic balls are placed on top to protect the catalyst. This post was last edited by johnhwa on 2009-2-26 09:51]
It should be “suppress” or “compress”. The catalyst bed includes..., and a compacted layer of alumina ceramic balls.
For support purposes, catalysts are generally placed on ceramic balls; in this case, it is aluminum oxide balls
Suppression, restraint, reduction, containment, lowering, binding. The function of this layer is to secure the supporting layer (alumina balls); is \"securing\" a better translation?