United States Patent 3123446

Publication Date:
03/03/1964
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Primary Class:
Other Classes:
29/896.620, 428/601, 428/596, 210/496
International Classes:
B21F27/18; B64C21/04; B64C21/06; B21F27/00; B64C21/00
US Patent References:
2711828Plastic fabric filter
2925650Method of forming perforate metal sheets
Foreign References:
GB3245924A