PURPOSE: To prevent a filter from being choked with dirt caused by liquid and a float from the malfunctioning by constituting a portion of the filter with a water-impermeable material while constituting another portion with a water- permeable material.
CONSTITUTION: The bottom surface of a filter device 18 is composed of a water- permeable filter 19 of a water-permeable material and the side is composed of a water-impermeable filter 20 of a water-impermeable material. Sucked liquid and air flow containing dirt are separated by a filter device 18 and only air is sucked into an intake port 3. Then, even if liquid is deposited on the water-impermeable filter 20, the liquid does not soak into the filter so that the filter is hardly choked. On the other hand, when the liquid sucked by the water-permeable filter 19 is accumulated on the bottom of a dirt collecting receptacle 24, it invades in the filter device 18 through the water-permeable filter 19 to lift up a float 17 upward, and finally dirt is sucked until the air intake port 3 is closed by the float.
YOSHIMI KAZUYOSHI
SUETSUGU NAOKI
