IPC 2013 : D21F 1/62 : Sand traps.

IPC2013 > D > D21 > D21F > D21F 1/00 > D21F 1/62[1] > Sand traps.
D SECTION D — TEXTILES; PAPER.
D21 PAPER-MAKING; PRODUCTION OF CELLULOSE.
D21F PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON.
D21F 1/00 Wet end of machines for making continuous webs of paper.
D21F 1/62 · Sand traps.