However, in the example of FIGS 4 6, the pump 53 is operable to perform the discharge and {TAIL ~ suction} of fluid separately in the fluid channel 44 of the first layer and {HEAD ~ the fluid channel} 54 of the second layer 
However , in the example of FIGS 4 6 , the pump 53 is operable to perform the discharge and { TAIL ~ suction } of fluid separately in the fluid channel 44 of the first layer and { HEAD ~ the fluid channel } 54 of the second layer
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH