Water pump and pipes

[djayz]

We suck water for the plants from our fish pond and the pump is approximately 1.5m above the water surface.

 

Initially, the intake pipe came out at the pump level and there was one 90 degree elbow on it which then went into the water.

 

Recently, I changed the intake pipe, for reasons I won't bore you with, so that there are now 2 x 90 degree elbows and a further elbow (45 or 60 degree, not sure) which then dips into the water. 

 

Neighbour and my missus are both telling me that the initial vertical in take was better than my new way, but neither of them can explain why. 

 

Honestly, I don't notice any difference when watering. This leads me to wonder if the less bends in the intake pipe is, in fact, the better option. Any thoughts on that? 

[nigelforbes]

I never use 90 degree angles on anything that carries water, pump lines downspouts or whatever, friction impedes flow. Always better to use 2 x 45 degree, I think.

[couchpotato]

This leads me to wonder if the less bends in the intake pipe is, in fact, the better option. Any thoughts on that? 

 

Yes the less bends the better (less air being trapped and pump doesn't have to work so hard).

This really applies to any home water system--less bends, usually better flow.  If need to use, then 45 deg better than 90 deg.

[djayz]

25 minutes ago, nigelforbes said:

I never use 90 degree angles on anything that carries water, pump lines downspouts or whatever, friction impedes flow. Always better to use 2 x 45 degree, I think.

 

24 minutes ago, couchpotato said:

This leads me to wonder if the less bends in the intake pipe is, in fact, the better option. Any thoughts on that? 

 

Yes the less bends the better (less air being trapped and pump doesn't have to work so hard).

This really applies to any home water system--less bends, usually better flow.  If need to use, then 45 deg much better than 90 deg.

Looks like it's back to my original pipe then... Thank you both. 

[couchpotato]

1 minute ago, djayz said:

 

Looks like it's back to my original pipe then... Thank you both. 

Try the straight pipe from the pump, then a 45 deg angled pipe into the pond.

Think you'll find that optimum.   

[VocalNeal]

Friction loss. What a load of twaddle.

 

The friction loss for 2 x 45 is almost identical to one single 90 bend. (2x 2.5 vs. 1 x 5.5)

In the OP's case he did add bends but friction loss depends on velocity. 

 

If the new intake works fine just leave it be. 

 

In gutter down spouts the 45 vs. 90 discussion centres on blockage due to birds nest et al not friction loss.

[kickstart]

9 hours ago, VocalNeal said:

Friction loss. What a load of twaddle.

 

The friction loss for 2 x 45 is almost identical to one single 90 bend. (2x 2.5 vs. 1 x 5.5)

In the OP's case he did add bends but friction loss depends on velocity. 

 

If the new intake works fine just leave it be. 

 

In gutter down spouts the 45 vs. 90 discussion centres on blockage due to birds nest et al not friction loss.

We have pump, pumping from a pond it goes all over the garden, never a problem, except now the water level has dropped and it is getting near the sediment at the bottom of the pond.

Point, we use a straight pipe from the pump in to a 90 deg elbow, as I said works fine, same as when the pond was full and now with not a lot of water in it

Then the land got flooded last year I had to pump water out of the pond so water on the land could flow into the pond, had to rig up a new system, very slightly less head, same pump this time I used 45 deg bends, worked just as well as the 90 deg bends same flow rate. 

[jvs]

In theory always use a 45 if you can because of the reasons already stated

by two other posters.

In a closely monitored set up you could probably measure the difference but see it?

it is just a water pump and one way or the other does not make a lot of difference.

Same as the argument for bigger speaker wires,you can measure it but can you actually hear it?