| 摘要 |
PURPOSE:To improve the seal feature and performance by providing many fine recesses or spikes or fine grooves at least on either the surface of a rotor or the inner peripheral surface of a housing. CONSTITUTION:Many fine recesses 12 are provided on the surface of a rotor 4 as shown in the figure. As an example, the recess is formed in a cone shape with its tip located at the bottom as shown in the figure, having a diameter (d) of 4-5mm., a depth (h) of 1-1.5mm., and an interval (l) of 8-10mm.. When these recesses 12 are applied on the rotor surface of a Roots-type blower with a required power of 2.7kw, a rotating speed of 1,500rpm, a wind quantity of 1.72m<3>/ min, and a wind pressure of 0.40kg/cm<2>, the wind quantity and wind pressure are increased to 1.84m<3>/min and 0.42kg/cm<2> respectively even with the same rotating speed and power, thus improving the performance by about 12%. The recesses 12 may be provided on the inner peripheral surface of a housing, and the seal feature and performance can be likewise improved by providing fine grooves or spikes in place of the recesses. |
