Can a combi run 2 body jets and a fixed head?

[Jackuzi]

Do some noddy sums. If you work on 10 litres/min, and a vertically faced jet with 100 holes 1mm diameter, one metre above the floor, then the initially horizontal spray comes out at 4.6 mph which isn't thrilling, and hits the floor 1 metre out from the head. That ignores air resistance and all that, which will make it worse.

That isn't running water - it's walking! Better start measuring your holes.

Bloody hell, I thought I was clever I think I'm not quite getting what you mean, can you help further? I will be running a fixed head shower with 46x0.5 mm (approx) holes mounted at standard height. I am flexible a to what body jets I install, obviously if ones with fewer/smaller holes will help then those would be my choice.
The ones I have in mind are http://www.homesupply.co.uk/proddetail.php?prod=JET2_C
Thanks

 

[ChrisR]

Well, fewer/smaller holes means faster water. An electric shower only produces about 4 litres a minute but has tiny holes in the head so it feels better, even if there isn't much water.

If you have two different outlets (heads) connected to the same supply, more of the water will go through the one which has less resistance. It won't whizz out of a tiny hole if there's a big hole it can go through, so you'd need a control (limiting valve/tap) on the supply to the big hole. Many body-jet setups don't give you one.

errm. your holes are 1/4 size and 38 of em so water will be about 10 times faster - but if you had the two heads connected nothing much would come out of it.


sums - nothing clever at all:
10 litres/min = 0.000167 cu m/sec
shower head 100 holes 1mm diameter
Area = 100 * pi * 0.001 * 0.001 /4 = 7.85 × (10^-5) m sq
Speed = 0.000167 / (7.85 * (10^-5)) = 2.12 m/sec
= 4.76 mph oh dear.

Time for a droplet (or anything) to drop 1 metre
h = 0.5(g t^2))
so time = sqrt(2/9.81) = 0.451 secs
Time half a second, speed 2 m/sec, water will come out 1m.

 

[Jackuzi]

http://www.flickr.com/photos/95171218@N00/90618935/

This is the way I thought I could plumb this in. With the jets on a seperate 'tap' to the overhead maybe I could adjust the amount I turn the overhead 'tap' on to get the right flow? With this configuration I thought that I have the choice of just running the overhead or the body jets or both?

Thank you for posting that formula, I think I will be able to work it out from that. Is that formula using figures from your first example ie 100 holes at 1mm though or 46 holes at 0.5mm as I quoted?