摘要 |
In an apparatus for forming leak-proof joints between tubes and a tube sheet by the internal application of hydraulic swaging pressure, the flow of pressurized fluid from an adjustable pressure reduction valve is permitted or interrupted by a control valve. An actuator moves the control valve between its flow permitting and interrupting positions in response to a control signal. In the sensor, which is connected to the input and output sides of the control valve, a piston is movable in response to the difference in the input and output pressures to produce the control signal when a predetermined comparative pressure relationship exists.
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