8421.91 - Of centrifuges, including centrifugal dryers:

HTS code 8421.91 specifically covers parts for centrifuges, including those used as centrifugal dryers. This category is crucial for identifying and classifying components that are essential to the operation of these machines, distinguishing them from the complete centrifugal units themselves. The scope here is focused solely on the constituent elements and subassemblies of centrifuges, rather than the final product.

While the broader category 8421.9 encompasses all parts for filtering, purifying, and centrifuging machinery, 8421.91 narrows the focus to components originating from centrifuges and centrifugal dryers. This differentiates it from sibling categories like 8421.99, which would cover parts for other types of filtering or purifying machinery not classified under centrifuges. The primary distinction lies in the functional lineage of the part to a centrifugal device.

Within 8421.91, further subdivisions clarify the specific nature of these centrifuge parts. For instance, 8421.91.20.00 deals with drying chambers for clothes dryers and related components of such dryers, highlighting a specific application of centrifugal technology. Similarly, 8421.91.40.00 addresses furniture designed to house these clothes dryers. The remaining subcategory, 8421.91.60.00, serves as a residual for other parts not otherwise specified within this subdivision, ensuring comprehensive coverage for all centrifuge components.