JPS6414536A - Ventilation cap - Google Patents

Abstract

PURPOSE:To improve a countermeasure against wind and rain as well as a discharging characteristic by a method wherein a main discharging passage is formed between a first hood and a second hood and a sub-discharging passage is formed between the second hood and a ring body. CONSTITUTION:In addition to a main discharging passage 17 formed between a first hood 2 and a second hood 3, a sub-discharging passage 18 is formed. Invasion of wind and rain W from an arrow direction A at a front face into an extremity opening 15 is prevented by the first hood 2, a spherical convex part 8 guides the wind and rain W to weaken their striking force and their direction is varied in such a direction as they are hardly invaded. The wind and rain W striking from an arrow direction B of a side surface against both discharging passages 17 and 18 are blown through between both hoods 2 and 3 in such a way as their directions may not directed toward the extremity end opening 15 of a discharging cylinder 5 by a raised edge 10 of the second hood 3. A discharged gas E is guided by a spherical recessed part 7 of the first hood 1 so to as to become a smooth flow, passes through both main discharging passage 17 and sub-discharging passage 18 and is discharged out of a system, resulting in that a low pressure loss can be attained and a superior discharging characteristic can also be attained.