The invention relates to a butterfly type exhalation valve. The said butterfly valve comprises a bottom valve body of geometric shape viz. Cylindrical/oval shape with a boss at one end provided with smooth surface at other end to form a valve seat for mounting a butterfly type diaphragm. A support means (19, 22) provided at centre of internal diameter with two are more sector openings forming exhalation slots (16). A solid pin (20) forming fulcrum for said diaphragm provided in the centre of the said support. One or more locking grooves (23) provided to the outer vertical surface of said bottom valve body. A cap/lid means having rigid top provided with a hollow pin(5), at centre, in the inner side to enable to engage to (1) said solid pin of said valve body when mounted over the bottom valve body after locating said diaphragm to the said solid pin. One more slots (4) on the side surface just below the said top of said cap/lid provided for passage to exhalation air. One or more internal locking grooves (7) provided to inner surface of said cap/lid to engage with matching locking grooves of said bottom body. A circular rib (3) provided at bottom of cap/lid matching with the said boss of bottom valve body. REFERENCE FIGURES: FIGURE 1 AND FIGURE 3
