flow powered siphon ?

[nota]

I am trying to get a flow powered siphon to work

using a 2 hp water pump and 1 1/2'' pvc pipe and fittings

first tryed a 90 deg ''T'' but flow came out both sides
then tryed a drain part that angled in about 20 deg

note a flow powered siphon does not use gravity or air pressure like a common siphon
water flow in the main pipe picks up water in the side pipe

do I need ventures or how can this be done with common hardware store PVC fittings

http://rcgldr.net/misc/psdrawing.gif


why to suck leaves off the bottom of a fish [koi] pond without clogging up the pump/strainer/filter and just dump the dirt leaves and water out

[primummobile]

BYou can buy flow powered siphon heads at most hardware stores. I made one for our fish tank that I attach to the spigot in our sink. I bought the head with a valve so I can drain or fill the tank by changing thevalve position. All I had to get extra was the fittings to connect it to the tubing I wanted to use and I just used nylon compression fittings for that. I think it cost around ten dollars total.

[nota]

small hose siphon heads for a small tank sure BUT
my fish pond/pool is 30,000 gal 37' by 17' and 9 ' deep
that is why I want to use 1 1/2 '' pvc pipe
I need to move big leaves and dirt too at a high rate and volume
with out clogging
something a garden hose sized unit will never do

[Solfe]

Build a venturi tube. How much space do you have?

ventri.jpg

This is a really rough drawing, but start with a 2 inch pipe on the left, reduce to 1.5". On either side of that reduction, place a T-connector down. Add in 90 or 45 degree bends as needed to build T shaped pipe. You may need to reduce the size of the pipes on the bottom simply so you can cut the pipe to short distances, like 8 inch lengths. Even then, the whole thing may stand 2 or more feet tall.

[nota]

space is no problem

latest try I used a long thin funnel cut off then heated the open end to fit tight in the 1 1/2 pvc Y fitting
and had the end extend past the junction of the Y a few inches
I got a weak flow but not enough to suckup the bottom litter hard or fast like I want

anyone know the size relationship of the out flow end to the suction pipe size
currently have 1 1/2'' pvc with the out end reduced to about 1/2'' over the 10'' taper of the funnel

do I need a funnel shape after the Y on the out flow end too ?

[billslugg]

The first thing you need to do is to size the nozzle that handles the flow from the pump. Doing this is not easy without a published pump curve. Your desire is to get the maximum amount of work out of the device. Thus you must have the maximum amount of input power from the nozzle. The power is equal to the flow times the pressure. You might try a variety of nozzle sizes, drilling them out for each step in the experiment. You can start with a small hole. In each case you measure the pressure at the pump discharge and you measure the flow rate in arbitrary units. Multiply the two together and plot the result against hole sizes, from maybe 1/4" up to 1". You will have a bell curve of some sort. Chose the peak of the curve and make a nozzle of that diameter. It must have a smooth entry with no sharp edges.

Then you mount the nozzle so it aims into the discharge opening. The size of that opening must be larger than the flow stream in order to allow still waters to be entrained and ejected. Larger is better until you get too large and the contents of the discharge line leak back into the suction side. You have to experiment with this one.

[nota]

pump is a older sears 220v 2 hp cast iron well pump with a center 2 '' suction in and 1 1/2'' top discharge
but only using about 1/2 the flow output
using the other half to refill the pool

I would like to know ideal venturi to in and out let pipes size
and distance of pipe past the venturi needed
and any other critical size or distances

looking the strongest suction not so much G per M flow

[nota]

tryed a 1/4'' out let then a 1/2'' and 3/4'' on the venturi

1/4'' was about 3 or 4 '' past the Y junction and resulted in very weak suction/flow
1/2'' was about 2'' past the Y junction no flow [cut funnel shorter]
3/4'' was before the junction and resulted in backflow [short coke bottle top cut off and heat formed to fit]

15' pipe run from pump to Y
10' out after the Y both 1 1/2'' pvc

[nota]

IT IS ALL IN THE NAME

firefighters call them a jet siphon
that is why google had so little

http://www.s-k.com/pages/pro_01_01.html

and it looks like a 5 to 1 jet to pipe size works
also they need a reverse funnel shape on the outflow
at lease the pictures show a reverse taper

[nota]

test and success

I added a 2'' Y fitting with a 2'' suction and 2'' discharge pipes
I guess it needed a bigger chamber around the discharge jet
with a 1 1/2'' pressure pipe from the pump reduced to 1/2'' out flow by the funnel

now my bottom pool vac head is clogging with sticks and leaves
I guess I need a bigger suction flex line and vac head both currently 1 1/2 ''
but it pulls the air out quickly after the clog is cleared

total cost was about 3.00 for the Y fitting and 1.50 for the funnel

note no out flow side funnel yet

[billslugg]

Congratulations!

[nota]

side benefit using the jet siphon without the suction side in water to refill the pool
it pulls in a huge amount of air mixing O2 with the ground water very well
so no need for spray heads or surface flow to add O2

[Solfe]

Very nice! Thanks for the update.