It cannot be stressed enough that Y strainers should be used for protection of downstream components and not for removal of unwanted particulate. When there is a constant influx of particulate to be removed you would be better suited with a simplex or duplex strainer.
A Y strainer has the advantage of being able to be installed in either a horizontal or vertical position. However, in both cases, the screening element or "leg" must be on the "downside" of the strainer body so the entrapped solids can be properly collected and held for disposal.
We have written two articles involving Y strainers: SIMPLEX STRAINERS: Differences between Y and Basket Style Strainers and How to Choose Between a Wye and Tee Strainer.
We offer Y strainers in sizes from ¼" to 24", constructed of cast iron, bronze, carbon steel, stainless steel CPVC, PVC, clear PVC - threaded, flanged socket weld and tri-clamp connections. Chamber gaskets are typically Gylon or Grafoil.