| 摘要 |
An air-operated valve which can keep the impact at the time a valve part sits on a seat from causing material from shedding and thereby generating particles which contaminate a controlled fluid and thereby can maintain a high cleanliness of the controlled fluid, that is, an air-operated valve which is provided with a valve chamber body which has a valve chamber which forms a seat, a valve mechanism which is provided with a valve part which seals the seat and with a diaphragm in the valve chamber, and a housing body which houses a drive mechanism which uses working air to make the valve mechanism advance and retract to drive and control it to open and close the seat, the drive mechanism provided with a first piston, a first spring which biases the first piston, a second piston which is slidably housed in the housing body and slidably houses the first piston inside it and which pushes the first piston, and a second spring which biases the second piston, the spring force of the second spring being made larger than the spring force of the first spring.
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