Gas mask for operation in contaminated areas

A gas mask for operation in contaminated areas, comprising:

• a facepiece;
• a nozzle tightly engaged in a lower portion of said facepiece and having a front portion facing toward an outer environment and a rear portion joined together with said front portion and having a width smaller than the width of said front portion, said nozzle including an inflow opening having a fitting adapted to hold a filter, said inflow opening being located in a lower portion of said nozzle;
• a half mask situated at an interior region of said facepiece, tightly engaged with said rear portion of said nozzle and provided with a terminal edge adapted to provide a seal around the user's nose and mouth, said inflow opening communicating with said interior region of said facepiece;
• connection means for enabling passage of air from said interior region of said facepiece to an interior region of said half mask;
• closing valve means for opening and closing said inflow opening;
• an outflow opening placing said interior region of said half mask into communication with the outer environment, said outflow opening being located in a lower part of said rear portion substantially at the level of and behind said inflow opening;
• a single-acting outflow valve for opening and closing said outflow opening;
• a phonic cap housed in said nozzle and situated above said inflow opening and said outflow opening;
• a communication chamber positioned within said nozzle at the level of said phonic cap and including communication holes to the outer environment;
• an inflow chamber which opens bilaterally in said lower portion of said facepiece near opposite sides of said rear portion and is positioned between said inflow opening and said interior region of said facepiece to enable said inflow opening to be in communication with said interior region of said facepiece;
• an outflow chamber positioned between said outflow opening and said communication chamber to enable said outflow opening to be in communication with the outer environment through said communication chamber, said communication chamber being located above said inflow opening and said outflow opening;
• and
• a partition located inside said nozzle and mutually separating said inflow chamber and said outflow chamber from each other, said partition being tightly connected with the peripheral extent of said rear partition and having a width smaller than said width of said front portion of said nozzle.