dear guys how are u ?? i ve a problem with selecting a centrifugal pump for circulating water in a closed system this system consists of tank , pipes up to 60 meters with 2 inch dia , then these pipes deliver water to a tube contains pressurized nitrogen @ 10 bars then return back to tank and also at the same time this nitrogen also affect on the water free surface inside the tank with 10 bars also i hope i have descriped the system clearly so guys tell me the manual says that this pump is 20m of head and 12m3/hr flow so what do u think the characteristics of this pump i think this pump is a normal pump 12 m3/h and 20 m but can withstand high pressure up tp 10 bars because the pressure is acting on both suction and delivery sides also this pump should have mechanical seal not galand packing to avoid leaking am i correct or not ????