 Abstract: |
768.557. Breathing masks. SINTERED PRODUCTS, Ltd. May 2, 1955 [Feb. 3, 1954], No. 3230/54. Class 81(2) A breathing mask has an air filter of porous metal. The breathing mask comprises a piece 1 of ductile porous metal, e.g. phosphor - bronze, which is moulded to fit the face. A gauze pad 2 is fitted between the porous metal and the face. The size of the pores is preferably 0.0005 inches but may be as large as 0.001 inches. In use the porous metal is wetted with an antiseptic liquid.
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