| 摘要 |
The apparatus is an oscillator for a showerhead to keep the forming fabric of a papermaking machine clean and open. A hydraulic cylinder is formed with a piston cup assembly dividing the cylinder into first and second fluid chambers. The piston cup assembly is coupled to a magnet and a driveshaft, the driveshaft being coupled, in turn, to the showerhead to be oscillated. A four-way valve is used to direct fluid from a pressurized external source alternately into said first and second fluid chambers thereby causing reciprocation of the driveshaft. The position of the magnet, and hence the driveshaft and showerhead, is monitored by a transducer which sends position and rate signals to a microprocessor-based controller. The microprocessor-based controller sends a signal to the four-way valve to direct which of said first and second fluid chambers receives fluid from the pressurized source in order to achieve the desired parameters of reciprocation. Additionally, the microprocessor-based controller provides an alarm signal should the driveshaft rate drop below a preset value.
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