Fluid mechanics

If I have an inlet pressure of 50psi, 840 gph and an orifice of 1". This then goes into a 10 gallon tank 24" tall. The outlet of the tank is 1/4". What is the pressure coming out of this orifice?
-Rod

 

[packdad]

What type of fluid is it? Also, to what pressure does the system ultimately discharge to? If it's water, and not knowing any more details, it doesn't seem that a one-inch orifice for 840 gph would create much of a pressure drop. Is it really an "orifice"?