| 摘要 |
Disclosed is a screen-type spirometer having an improved pneumotachometer, which has a simple structure and a low manufacturing cost and is convenient to use. According to the present invention, the pneumotachometer includes a hollow housing having an annularly shaped ring and a first respiratory tube integrally formed with the annularly shaped ring. The first respiratory tube can be inserted into a mouth of a person to be examined. The pneumotachometer also includes a second respiratory tube which can be engaged with the housing and be inserted into the mouth of the person. The first and the second respiratory tubes have a tapered portion, which is inclined at 10 degrees, respectively in order to stabilize a fluid flow of respiratory gases passing therethrough. O-shaped first and second sensing units for sensing a differential pressure of the respiratory gases passing through the pneumotachometer are disposed within the housing. A circularly shaped screen operating as a mechanical resistance against the respiratory gases is disposed between the first sensing unit and the second sensing unit within the housing. Prepherably, a suitable size for the screen has been found to be in the range of a screen having a mesh of 300 openings per inch. The pneumotachometer comprises a blowing apparatus for drying and cleaning the screen at need. The blowing apparatus is provided as an individual unit. A handle is attached to an outer surface of the annularly shaped ring. |
