Backyard Aquaponics
A place to discuss aquaponics

I did some research while try to get around the issue of Head Loss/Friction in the pipe work..

I found out that 50mm Telstra bends will work with 50mm pressure pipe..

So in the case of having to change direction, instead of using a tight 90bend[PP] use a 90sweep[T]..

I'l get some photo's of what I have done with the fitting once I start the pump Line..

Now if I was in America.. I would be in heaven I think.. They have everything you could need to help reduce head pressure..

Go to http://www.lowes.com/

I know I'm bad, but have you seen what they have in store and the price's..

Beats what we have hands down..

Juergen

two 45's will make a similar difference I believe. I'd love to see some actual flow numbers comparing a single PP 90 with either a telstra sweep, or two 45's and see if there is any real difference

well one of the things that I feel create an impact on the water flow is fact that water will travel the path of least resistance..

as water travel along a straight piece of pipe then all of a sudden it hits a hard right turn.. it loss a lot of power..
By using the sweep you ease the water around the corner..
- in commercial system where they circulate liquids they always try to use a sweep over a hard 90.. especially if the pipe work has to move abrasive material in the liquid.. Less friction/less abrasive damage..

Hope this helps..

Juergen

looking at the stats and graphs of a google search the having either 1 x 90deg or 2x 45deg there is no difference... but in saying that I think there would be more friction loss in 2x45deg as you have more cuts (4 not 2) and not to many of us could say that our cuts are perfectly straight so that means more spots for the water to make turbulence therefore less water through...

+1 ... and is any loss really that significant in a backyard AP system...

As rupt said

Ok here is the photo to show the difference's in each of the fittings..
- 50mm - Hard 90 bend Pressure pipe..
- 50mm - 2 @ 45 Bends - Pressure pipe..
- 3" - Male / female 3" electrical coupling's[USA only]
- 50mm - Telstra Sweep bend.. Comes from the same factory that makes the 50mm pressure pipe..

hope this helps explain where I'm coming from..

And Rupert.. I think when you have to raise the height of the exit of the return pipe about 1.5m, any reduction in head loss is important..

That is one of the things I would change if I had the chance to..

Juergen

Psst With the size of my system I'm looking at having to circulate about 10,000 lts of water so I'm using larger than normal efficient pump's..

Where can the Telstra bend be obtained from?

Probably true SnowT... but most systems wouldn't have a head much bigger than that....

And those that do.... will require a pump that probably means that friction losses (relatively)... again become somewhat inconsequential..... unless you've got a lot of plumbing...

Beware... Telstra pipe sizing, and even electrical pipe sizing.... are different to "pressure pipe"...

Indeed Telstra and electrical sizing aren't often compatible....

You can get "sweeps" for pressure pipe sizes...

I really don't see how its worth saving the 1-2 feet worth of pipehead pressure loss per fitting at the risk of adding a possible failure point. That pipe has been heated and bent so the walls are no longer the same. It rated for electrical conduit use and around here not even allowed for that. I have a lowes ten minutes away and in that store and home depot that stuff is no where to be seen. They have a few fittings for the grey plastic conduit and it makes great little bulkheads but as for trusting it on a pump line with vibration on a short run? I would rather run the next size up in pipe if I was worried about it.

Any good electrical wholesaler should have them..

Yes the 50mm sweeps are heated to form them into shape.. But done in the correct procedure they loss no strength..

And yes I know that most would not recommend them for the job I'm about to place them..But have you thought of Why they don't recommend them.. ??
Same tight fit as a pressure pipe..
Oh yeah I'm using Pressure pipe for the main Pipe[thick walled] not the thin walled Telstra Pipe..

- Their Bell is deeper than a std pressure fitting..
- they have the same wall thickness of the pressure pipe..
- they are cheaper than an equivalent pressure fitting..[If I could find the equivalent fitting]
--> I have Asked if there was a Sweep Pressure fitting and have been told that no such thing exist..

Ask any plumber worth his weight, and they will tell you if you have the room..
A large radius bend[Sweep] is far better for Flow over tight bend's..
- Less damage via scouring than tight bends..
- Less hammer than tight bends..

A few feet of head loss.. == to better flow at 1.5m compared to 2m..

It all comes down to FLOW..

Juergen

On drains we would always try to use long sweeps. On pressure I know it makes a difference and I have seem it but the fitting that are rated for it are pricey and no one really bothers. Systems and jobs I have been on never really called much for anything like that except a few places with very long runs with many bends in very old buildings running NH3 for refrigeration. I don't think I ever used long sweep pressure elbows other then stainless steel weld on ones.

I do know if anyone I worked with put the electrical long sweep like that on a pressure system or even liquid filled we would probably get fired. ( when I did have a job)

Al you can do is look at engineering data on it and make a decision but if its not rated for it is it worth the risk?

How many 90s are you replacing? What is the pump flow to pipe size? If the flow is low for the pump volume it really might not make much difference at all. Longer sweeps make a real difference at high flow rates or gravity but in a big pipe with low pressure from what I remember it does not make much difference. Its been years since i was in class doing the actual math on stuff like this so my brain is a bit fuzzy.

Given that pond pumps dont put out actual pressure, means that using pressure pipe is overkill anyway. If the fittings are cheaper, fit where you want, and the pipe glues in nicely, then I say go for it and tell us how it works.

cheers

Got an update..

The 50mm Sweeps are in the system.. it seems to work well.. There is not much Pressure as I have gone from a 32mm output to a 50mm pressure pipe..
I'm currently pumping about 8000lt's and Will be upping that to 12,000lt ASAP..
At what ever the currently flow-rate into the system is, I don't know.. But it is run's constant the levels hardly moves..

I have also found that smaller Telstra fitting[25mm] also work fine.. Better sockets than that of pressure fittings.. So for low pressure systems it works well..

I have used std fitting for the air system..

Juergen