Asymmetrical momentum?

[d4rr3n]

gravx5.gif

If we analyse the forces in the above image we have:

1 Gravity pulling downwards
2 The momentum of the fluid in the horizontal pipe which is also horizontal.
3 The momentum of the fluid ascending half the arc on the left and descending the other half on the right, these two forces being equal in magnitude and opposite in direction should cancel to result in zero overall momentum.
4 The centrifugal force of the fluid as it circulates over the arc section causing it to be flung to the outside of the arc much like clothes in a spin dryer. If arrows are drawn for this force you have multiple arrows radiating out from the center of the arc none of which point downwards.

My question is where is the downwards force to balance the largely upwards centrifugal force?

[JAlberts]

You have the downward effect of the weight of the pump and piping; plus, if you modify your model to provide curved sections at the two ends of the pump horizontal pipe, you will see that you have a 45 degree downward and outward force vector at each of those corners, the vertical components of those vectors will also provide a downward force to oppose the upward force in the loop. In addition there is the effect of the downward force of the total weight of the fluid in the system.