Design of hydraulic pressure driven rodless drainage control system

For low control precision and work efficiency of existing rodless drainage equipments of coalbed methane and large labor intensity in drainage field, a hydraulic pressure driven rodless pump was designed as well as a hydraulic pressure driven rodless drainage control system based on PLC. The system uses underground pressure transmitter to measure bottom-hole flow pressure and PLC to control inverter to adjust motor speed through comparing measured flow pressure with the set one, so as to adjust bottom-hole flow pressure. The hydraulic pressure driven rodless pump does reciprocating motion, which is driven by power fluid in power fluid pipe of three-channel oil pipe, so as to realize automatic up-down switching between valves without labor operation. The experimental result shows that the system can adjust bottom-hole flow pressure to approach the set one quickly and correctly with small overshoot.