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Max Pump Hose length
http://byap.backyardmagazines.com/forum/viewtopic.php?f=8&t=1127		 Page 1 of 2
Author:  nameviolated [ Jan 26th, '07, 13:21 ]
Post subject:  Max Pump Hose length
Have now got my 500 Litre Bin (Will post pic soon). From where I am thinking of setting it up to where I am looking at putting the grow beds is some distance (At least 8 metres). Is this to far? Also trying to work out pump size, but previous posts seem to be based on grow bed very close to tank. Any ideas?
Author:  Daniel [ Jan 26th, '07, 13:43 ]
Post subject: 
I think there is a flow rate calculator for pipe on the forum somewhere. The longer the pipe, the more resistance, but im my opinion it would be fine (just might need a larger pump to get same flow rate)
Author:  Aquaddict [ Jan 26th, '07, 13:47 ]
Post subject: 
You'll have far more drag on the pump concerning height, as opposed to distance.

In downloads you can look at the calculators there, but I didn't cover pump head and distance etc, just approx volume of pump for size of system. Slightly bigger than needed is always better than slightly smaller than needed, can be throttled back.
Author:  Daniel [ Jan 26th, '07, 13:48 ]
Post subject: 
just searched, i was thinking of the pipe volume calculator
http://www.backyardaquaponics.com/forum ... file_id=12

the only potential prob i see with a longer pipe is loss of heat maybe if exposed to elements...and pvc coming in 6m lenghts you would have an extra join, but if sealed is no prob..
Author:  Nova [ Jan 26th, '07, 14:27 ]
Post subject: 
This page hase some tables to calculate pipe friction loss. Because you lose velocity/pressure due to friction you will need to allow more flow to compensate. The amount of loss it usually measured in meters of head, as this allows you to easily work out what flow rate you need.

For example if you need a flow of 1000L/hr and you have to lift the water 1m above the fish tank level this allows you to size the pump accordingly. If you only have a small amount of pipe 1-2m the loss is negligable (as long as the pipe is not tiny), however if you have 20 or 30m then you may need to allow for the loss. Now 1000l/hr is .27L/s, and the table linked below shows a friction loss of .2m of head per 10m of pipe in 25mm pipe. This means you effectively have to pump an extra .6m high to allow for the friction loss over 30m.

The easiest way to overcome this is to use bigger pipe, 40mm pipe only loses .02m of head for 10m of pipe.

http://www.wdmoore.com.au/tdh.htm

Have I made it any clearer?

Nova
Author:  nameviolated [ Jan 26th, '07, 14:35 ]
Post subject: 
I think so will need to check links, before deciding on how clear. What is a bio film?
Author:  Nova [ Jan 26th, '07, 14:38 ]
Post subject: 
Bio-film is algae and other gunk that will build up inside the pipes.

Nova
Author:  nameviolated [ Jan 26th, '07, 14:40 ]
Post subject: 
thanks will check it out
Author:  nameviolated [ Jan 26th, '07, 16:12 ]
Post subject: 
Daniel wrote:
just searched, i was thinking of the pipe volume calculator
http://www.backyardaquaponics.com/forum ... file_id=12

the only potential prob i see with a longer pipe is loss of heat maybe if exposed to elements...and pvc coming in 6m lenghts you would have an extra join, but if sealed is no prob..


this gives me 11 litres, what does that mean? I gather its not per hour.
Author:  Gary Donaldson [ Jan 26th, '07, 18:13 ]
Post subject:  Re: Max Pump Hose length
Hi,

Quote:
Slightly bigger than needed is always better than slightly smaller than needed, can be throttled back.


AA means that you should install a bypass line back into the fish tank to reduce the flow rather than restricting it. This is much better for the pump and you can use the spare flow to run a trickling bio-filter or to aerate your water.......bigger bang for your pump buck.

Gary
Author:  Daniel [ Jan 26th, '07, 18:33 ]
Post subject: 
nameviolated wrote:
Daniel wrote:
just searched, i was thinking of the pipe volume calculator
http://www.backyardaquaponics.com/forum ... file_id=12

the only potential prob i see with a longer pipe is loss of heat maybe if exposed to elements...and pvc coming in 6m lenghts you would have an extra join, but if sealed is no prob..


this gives me 11 litres, what does that mean? I gather its not per hour.


That just gives you the volume the water holds, i remember seeing a page that gave you the maximum possible flow rate, and the maximum practical flow rate of water through pvc pipe, but i cant seem to find it
It took into account various factors such as length of pipe, diameter of pipe and i think even temp of water, etc

But nova has a link to a page, which is prob just as good (not sure if you even need to bother that much with it though if you get a bigger pump like aa said (and if theres too much flow, then you could do what gary said)

i dont think i have been of much help though
Author:  nameviolated [ Jan 26th, '07, 19:58 ]
Post subject:  Re: Max Pump Hose length
looking at something like \this
Author:  nameviolated [ Jan 26th, '07, 20:08 ]
Post subject:  Re: Max Pump Hose length
or this
Author:  steve [ Jan 26th, '07, 22:02 ]
Post subject: 
Just be CAREFUL with the max head / max flow

if it states max head is 2.5m then it will push the water up 2.5 meter but will not flow anything, and even at 2m the flow will be little more than a trickle.

If it states 1500L/hr then thats at ZERO head, pretty much straight out of the pump horizontal with minimal pipe lenght.

When they quote the specs it definatly a case of having their cake and eating it too.

Don't for one second think that it will pump 1500L/hr at a height of 2.5M

I'm repeating myself again, but i think its worth the extra post.

Steve
Author:  Dave Donley [ Jan 26th, '07, 22:30 ]
Post subject: 
Steve, isn't your grow bed kind of far from your tank?
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