| CPC F15B 15/22 (2013.01) [B05B 9/0409 (2013.01); F15B 15/1433 (2013.01); F15B 15/149 (2013.01); F15B 15/1457 (2013.01)] | 16 Claims |
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1. A fluid injection or suction device that injects fluid to a target space or suctions fluid from the target space through nozzles, the device comprising:
a cylinder formed in a hollow tubular shape and closed at opposite opening end portions by closing members;
a piston that is inserted in the cylinder in a relatively movable manner between the opposite opening end portions, and that partitions an interior of the cylinder into a first fluid chamber and a second fluid chamber;
a guide extending from the piston inserted in the cylinder, penetrating the closing members to an exterior of the cylinder, and fixed to support the piston and guide movement of the cylinder in sliding contact with through holes in the closing members, the guide including a first internal flow passage that connects the first fluid chamber externally to a first external pipe so as to communicate with each other, and a second internal flow passage that connects the second fluid chamber externally to a second external pipe so as to communicate with each other, the guide having an area of a circumferential outer shape smaller than that of the piston;
a first nozzle of the nozzles, through which the first fluid chamber and the target space communicate with each other; and
a second nozzle of the nozzles, through which the second fluid chamber and the target space communicate with each other, wherein
a pipe to communicate with a fluid pressure source that generates fluid at a predetermined pressure is configured to switch between the first external pipe and the second external pipe,
a flow passage from the fluid pressure source to the first nozzle and the second nozzle includes a short-circuit flow passage that short-circuits the first fluid chamber and the second fluid chamber, and that enables fluid to flow bidirectionally, and the short-circuit flow passage is provided with a throttle unit that throttles a flow passage, and
the throttle unit is configured to cause the fluid to flow from a high-pressure-side fluid chamber toward a low-pressure-side fluid chamber according to an internal pressure difference generated between a fluid chamber that is one of the first fluid chamber and the second fluid chamber and that communicates with the fluid pressure source, and a fluid chamber that is the other of the first fluid chamber and the second fluid chamber and that does not communicate with the fluid pressure source, so as to cause the piston to relatively move, while reducing a volume decrease rate of the low-pressure-side fluid chamber
wherein the short-circuit flow passage is formed in the piston,
a through hole is drilled, penetrating the piston from a side facing the first fluid chamber to a side facing the second fluid chamber, and a plug is removably fitted into the through hole, and
the short-circuit flow passage is formed in the plug, through which the first fluid chamber and the second fluid chamber communicate with each other.
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