conclusion:
the block is fairly restrictive, 0.7m at 5lpm (0.58psi @ 1gpm), however (hopefully) the pressure drop is put to good used by increasing the water jet velocity.
i was curious as to the effect of the base plate on the flow resistance (what proportion of the pressure drop is "used" by the jets, and how much is "wasted" in getting the water back up the cups and out of block.
Welp, i measured the block flow rate as 5.3 lpm with this pump and the 3m of piping (see graph)
when i removed the base plate, the flow increased to 5.9 lpm. (big deal, huh)
however… this translates to approx 0.45m @ 5lpm for the block without the base. (instead of 0.7m with the base) hope you're following.
Therefore we can say that the base adds a fairly considerable restriction - this is actually more than 50% extra head loss. (+- quite a lot
)
However, interestingly, and perhaps suprisingly this makes very little difference to the flow rate (-10%).
Bear in mind that this is specific to one particular pump, but i guess you can generalise it if the system is operating in the "top region" of the pump PQ curve.
*This bit of info could be of use to those of you running 2 or more blocks in series…*
</getalife mode>
phew, sorry for going on a bit there, hope someone will find it useful
