| 摘要 |
PROBLEM TO BE SOLVED: To provide an economical dust mask with a pressure fluctuation sensor which enables handily and accurately learning of the period of replacing a filter material and adaptation to a difference in the respiration quantity of a wearing person without use of any costly device. SOLUTION: A filter material is set at a suction port and an air passage hole 26 is bored communicating between the inside and the outside of a mask body 2. A whistle 7 is mounted the external surface of the air passage hole 26. A diaphragm 28 is provided inside the air passage hole 26, a spring 30 is arranged inside the diaphragm 28 to energize it to the air passage hole 26 and a pressure varying sensor is so arranged to comprise an adjusting means for adjusting the pressure of the spring 30. The diaphragm 28 closes the air passage hole 26 in the ordinary state and separates from the air passage hole 26 with a drop in the pressure inside the mask body 2. As a result the whistle 7 emits a sound, thereby notifying clogging with the filter material. |
