Fluid injection or suction device

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, and
• the fluid injection or suction device includes a short-circuit pipe that connects the first external pipe and the second external pipe so as to communicate with each other, and a flow-rate adjustment valve is disposed in the short-circuit pipe as a throttle unit that throttles a flow passage.

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 by a flow-passage switching valve connected to the fluid pressure source through a pressure connection 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 a flow passage communicating with the fluid pressure source and a flow passage not communicating with the fluid pressure source,
• the short-circuit flow passage includes a first short-circuit pipe and a second short-circuit pipe, the first short-circuit pipe bypassing the flow-passage switching valve and connecting the pressure connection pipe and the first external pipe so as to communicate with each other, and the second short-circuit pipe bypassing the flow-passage switching valve and connecting the pressure connection pipe and the second external pipe so as to communicate with each other, and
• a flow-rate adjustment valve is disposed individually in the first short-circuit pipe and in the second short-circuit pipe as a throttle unit that throttles each flow passage.