The system 5, wherein the first check valve, the second check valve and the third check valve are arranged such that when {HEAD ~ the pump} is operated in the first state, fluid is delivered from {TAIL ~ the fluid source} to the first location and blocked to the second location; and when the pump is operated in the second state, fluid is delivered from the fluid source to the second location and blocked to the first location 
The system 5 , wherein the first check valve , the second check valve and the third check valve are arranged such that when { HEAD ~ the pump } is operated in the first state , fluid is delivered from { TAIL ~ the fluid source } to the first location and blocked to the second location ; and when the pump is operated in the second state , fluid is delivered from the fluid source to the second location and blocked to the first location
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH