I have been thinking today about our conversation about pipe sizes a week or
so ago, and I have decided I am still confused. If most pumps have 2-inch
fittings, what good does it do to have 4-inch pipe everywhere else? Isn't
the 2-inch connection the limiting factor?

My pond will have a bottom drain and a skimmer that will empty into a VF. A
pump in a pump house will pull water from the VF and dump it back into the
main pond. Currently my plan is to use 4-inch pipe from skimmer/bottom drain
to VF, 4-inch pipe from VF to pump house, and 4-inch pipe as a return to the
pond. I have not selected my pump yet, so I am not sure what I will need
there.

Any thoughts?

--
BenignVanilla
tibetanbeefgarden.com
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The pipe from the pump to the pond could be plumbed with the smaller pipe, 2
inch, since it will be on the pressure side of the pump. On the vacuum side
of the pump, the pipe friction will severely reduce the output of the pump,
since they are designed to push, not pull water. The piece from the main
pond to the veggie filter will only have gravity working to push or pull
water. If the pipe size is not sufficient, then the drawdown of the veggie
filter will be extreme to try to keep the volume of water flowing from the
pond to the veggie filter at the same rate as the water from the pump to the
pond.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"BenignVanilla" wrote in
message ...
I have been thinking today about our conversation about pipe sizes a week
or
so ago, and I have decided I am still confused. If most pumps have 2-inch
fittings, what good does it do to have 4-inch pipe everywhere else? Isn't
the 2-inch connection the limiting factor?

My pond will have a bottom drain and a skimmer that will empty into a VF.
A
pump in a pump house will pull water from the VF and dump it back into the
main pond. Currently my plan is to use 4-inch pipe from skimmer/bottom
drain
to VF, 4-inch pipe from VF to pump house, and 4-inch pipe as a return to
the
pond. I have not selected my pump yet, so I am not sure what I will need
there.

Any thoughts?

--
BenignVanilla
tibetanbeefgarden.com
x-no-archive: yes

Remove MY SPLEEN to email me.

The water as it comes out of the pump is in a small, but fast moving stream.
Water moving at this speed will encounter a lot of friction in the pipe.
If you upsize the pipe where it comes out of the pump the water will slow
down, and since slower moving water has less frictional losses the pump
will move more water.

The frictional losses are additive.

Howard

"BenignVanilla" wrote in
message ...
I have been thinking today about our conversation about pipe sizes a week
or
so ago, and I have decided I am still confused. If most pumps have 2-inch
fittings, what good does it do to have 4-inch pipe everywhere else? Isn't
the 2-inch connection the limiting factor?

My pond will have a bottom drain and a skimmer that will empty into a VF.
A
pump in a pump house will pull water from the VF and dump it back into the
main pond. Currently my plan is to use 4-inch pipe from skimmer/bottom
drain
to VF, 4-inch pipe from VF to pump house, and 4-inch pipe as a return to
the
pond. I have not selected my pump yet, so I am not sure what I will need
there.

Any thoughts?

--
BenignVanilla
tibetanbeefgarden.com
x-no-archive: yes

Remove MY SPLEEN to email me.

"BenignVanilla" wrote:

I have been thinking today about our conversation about pipe sizes a week or
so ago, and I have decided I am still confused. If most pumps have 2-inch
fittings, what good does it do to have 4-inch pipe everywhere else? Isn't
the 2-inch connection the limiting factor?

Yes, it is. Being at the pump, there is pressure available that can
over come (somewhat) that restriction.

Keep in mind (pi-r-squared) that pipe capacity increases faster than
diameter, so that you don't need to double the diameter to double the
flow capacity.

Any thoughts?

IMHO, on pressure piping (from the pump) you don't need to go more than
one pipe size up from the pump outlet. Unless you have a very long run,
or a lot of bends and turns, with a lot of resistance. So with a 2 inch
pipe output, that would be 2.5 or 3 inch pipe.

Large (3-4"+) is needed more for gravity flows, and such where you don't
have the flow rate you do with a pump. Not to mention debris.