Patent ID: 8257588

Claim:
An oil-water separator with self-priming pump including a separator portion separating a mixed liquid in which oil is mixed in water, and a pump device portion introducing the mixed liquid into the separator portion, the oil-water separator with self-priming pump having an arrangement where the separator portion includes a rough separation portion performing rough separation of the oil and the water by cyclone separation in which a swirl flow is generated by introduction of the mixed liquid into a cyclone cylinder, a main separation portion connected to a downstream side of the rough separation portion and performing main separation of the oil and the water according to specific gravity difference by passing the mixed liquid, which has undergone the rough separation in the rough separation portion, from above to below through a liquid passage formed in multiple-step form, a water discharge portion connected to a lower portion of the multiple-step liquid passage of the main separation portion and discharging the water from which oil has been separated and removed at the main separation portion through a water discharge passage extending from the lower portion of the multiple-step liquid passage to an upper portion of the separator portion, and an oil storage tank storing the oil separated from the water at the main separation portion and overflowing from an upper portion of the main separation portion, the pump device portion includes a self-priming liquid pump connected to a downstream side of the separator portion and connected directly or indirectly to the water discharge portion to introduce the mixed liquid into the separator portion by sucking the mixed liquid from an exterior of the separator portion via the rough separation portion, the main separation portion, and the water discharge portion, and by an upper portion of the rough separation portion and a portion above the main separation portion being communicatively connected by a communicating pipe, having one end connected to a portion of the rough separation portion positioned above the cyclone cylinder and having another end connected to a main body of the separator at a position above an overflow portion, which is an uppermost end portion of the main separation portion, and an upper portion of the main body of the separator, which is a portion above the overflow portion, and a portion above a liquid level of the water discharge portion and adjacent the portion above the overflow portion being communicatively connected by a communicating hole, a portion above a liquid level of the rough separation portion, a portion above the overflow portion that is a liquid level position of the main separation portion, and a portion above the liquid level of the water discharge portion are put in communication in a manner enabling air to be vented in that order and air, which has entered inside the separator, is thereby sucked and discharged by the self-priming pump.