| 摘要 |
PURPOSE:To reduce windage loss and enable recovering power in such a way that a safeguard for a propeller fan is formed by means of radial louvers, and the louvers are inclined toward the revolving direction at the position where is oposite to nearly the outer diametral part of the fan. CONSTITUTION:The center part of a safeguard 9 is made as a tightening part 9a, inner louvers 9b which provide inclined sections capable of recovering the rotating loss are formed radially around its outside, and after a ring 9c is formed in a ring shape on the way of its process, again outer louvers 9d which provide inclined sections capable of recovering the rotating loss are formed arond the outside of the ring 9c. Inclined angles in the revolving directions of the inner louvers 9b and the outer louvers 9d are recapectively 40 deg.-90 deg. and 30 deg.-90 deg.. In addition, widths B, B' of the louvers, and incised lengths l, l' are prescribed as a size which does not permit a finger to put into them (approximately 9mm.). |
