Filters contain a collection of pipes, valves, sight glasses, pressure gauges and other gadgets which come into contact with the product. The easiest (and least expensive) way to assemble them all is with flanges and pipe thread connections. These types
of connections are meant to be semi-permanent in that you only disassemble them when you have to replace something. This is called "Standard" execution. With "Sanitary" execution these devices are assembled in a manner which eliminates the pipe threads
and flanges, and replaces them with stainless welds and sanitary connections which are designed to be broken down on a daily basis without damage. That way, you've minimized a lot of the nooks & crannies where stuff can get caught, and a fastidious
worker can routinely disassemble it for cleaning without using a pipe wrench.