Pond Boss Forums POND CONSTRUCTION Building a dam vacuum pump

Hi,
I have a 10" diameter, probably 50' - 60' long siphon pipe coming out of a pond on a property I recently purchased. I'm searching for a vacuum pump that can pull air out of the siphon pipe to prime it, what do you folks use for this kind of job.

I've looked at regenerative vacuum/blower pumps but wasn't sure if it could do the job, or if I should look for rotary vane pumps. Also, there is no power available, so I'd prefer a gas powered pump (if there is one out there) or I will have to invest in a generator as well.

Thanks!

Welcome to the forum!!

Even a fairly small pump will draw the air out and pull water in...Cap off the outlet, tap into the siphon at the high point and connect the vacuum pump with the method of your choice. I personally used my aeration pump and put a clear bowl water filter between the siphon tube and my pump so I didn't trash the pump...Even a small "oil suction" pump can be used if no power is around.

Another method is to bucket fill the outlet side pipe....when you pull the outlet cap, the weight of the water exiting will pull the inlet pipe side full and usually start your siphon. Be sure it is air tight or it will be a waste of time all around.

A high flow vacuum pump would be hard to shut down before filling with water.....

We always attached a standpipe to the main siphon pipe, and equipped it with a fitting that we plugged an air hose from our gas powered air compressor into.... the pressurized air rushing past created a venturi effect, and drew water into the siphon pipe. No vacuum pump needed.

Naturally, plug the outlet side first.......

Thanks Rainman! I also searched an found an older post from you that you are using gast 72R, I will search ebay for those kind of pumps, also would like to try out the venturi.

sprkplug! what kind of venturi do you use? do you have a picture or link? I do have a 1 inch stand pipe at top of the siphon, and also have a air compressor. I will search for venturi but would be great to use the one you've already tried and tested.

Okay, I'll try to explain the method that we used for years. First, we would locate the standpipe right where the discharge broke over the backside of the dam. This pipe should incorporate a ball valve in its makeup also. At the top of the standpipe, we had enough pvc fittings to end up with a 1/4" brass, barbed hose fitting.

Our venturi consisted of a cheap engine wash gun .... It consists of a wand with a built in trigger, a fitting to plug an air compressor into, and a suction hose that would normally be placed into a bucket of cleaner, or degreaser:
http://www.amazon.com/Anytime-Tools-CLEANING-SOLVENT-Pressure/dp/B000PCDX34

We would connect the detergent suction hose from the gun to the barbed hose fitting on the standpipe, open the ball valve in the standpipe, plug the end of the discharge pipe that went over the dam, and squeeze the trigger on the wand. It doesn't matter if water gets into the cleaning gun because that's how it's meant to work, unlike the suction pump which may be ruined if it's not shut down in time. (found that out years earlier, before switching to this system)

Using this method, we would spray pond water out of the cleaning wand until the discharge pipe over the backside of the dam filled with water. Then we would close the ball valve in the standpipe, unhook the hose from the barbed fitting, and remove the plug or cap on the discharge pipe...instant siphon, provided the connections are airtight.

Here is a super simple venturi type vacuum pump... http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

If you have a water supply...a waterbed drain is a venturi also....run about $7 at walmart, but are plastic.

Here's an idea I've thought of but haven't tried yet. Maybe someone will test it to see if it actually works.....

Use a siphon to start a siphon.

1) Use a garden hose siphon, with a valved "T" at the high point.
2) Connect the "T" to the siphon vent on your main siphon.
3) Plug the output of main siphon.
4) Close valve on hose "T" and start the hose siphon and get it going full flow.
5) Open the valve on the "T" just a smidge so it starts sucking in a bit of air from main siphon.
6) Observe outflow from hose and adjust valve to maintain flow while expelling air drawn in from main siphon.
7) When bubbles no longer appear in outflow from hose siphon, the main siphon is primed and ready to go.
8) Open output on main siphon.

I think this should work and hope someone can test it out for me because I don't have any power at our place and am looking for an easy way to start the siphon.

-RFL

CH2429,

I like the idea sprkplug has suggested since I have used the same concept in my life of work.

When I want to fill an enclosed tube, standpipe or drill pipe, I would circulate fluid across the top of the tube, standpipe or drill pipe and since the water is heavier than air, the fluid will fall into the standpipe and displace the air within the tube until the standpipe fills up with fluid.

With the discharge side of the siphon closed off,I would pump or flow water slowly across the "T" until the standpipe is full. Isolate off the top of the standpipe by closing a valve or an air tight plugs and then open the discharge side plug.

A couple of things that crosses my mind when dealing with hydrostatic pressure and fluid is 1. the discharge plug will be under pressure so there my be resistance on the plug when attempting to remove. 2. As you begin to remove the plug and get closer to the end of the threads the cap or plug my be forced out of the remaining threads due to being under pressure and cause a flying hazard. 3. Once the cap or plug is removed there will be the force of the water escaping the discharge and if you are in the line of fire, you may be swept off of your feet but not in a romantic way either.

If your intake side has a valve to isolate it off, then you could 1. Isolate off intake side of siphon. 2. Isolate discharge side of siphon. 3. flow fluid across top if standpipe until full. 4. Isolate off standpipe side. 5. Remove discharge cap or plug. 6. Open intake side and allow siphon to begin.

Calculation of figure out the hydrostatic pressure will be (Height of stand pipe to end of discharge hole) x .052 x 8.33 (fresh water weight per gal or ppg)and will give you psi on that plug or cap on discharge. This will be approximate not considering the TVD (True vertical depth) of the angle of the discharge line.

Just my thoughts....Hope this is helpfull.

Couppe

You can get a Venturi vacuum fitting for hoses, so you can use a small garden hose siphon to pull the vacuum on a larger siphon to get the larger one started. Think pesticide sprayers you attach on the end of a hose, but a more permanent variety. Much easier to start a small hose with your lips.

You could probably set this up to be automatic, using a small pipe and Venturi, where the small pipe is leveled at the point at which you want the siphon to begin, and the main siphon inlet itself could be down at the bottom of the pond to suck in the cruddy water. Once the water drops below the small pipe, it lets air in, and breaks the siphon.

A small hole or two in the main drain pipe to break the siphon if things go wrong would be installed below the waterline in case the Venturi clogs.

Some ideas, though I am not finding the simple hose version right now.
http://www.venturipumps.com/gallery.htm

The key to getting the whole thing to work is having enough elevation drop to initiate the Venturi effect to pull the vacuum.

I didnt read through all of that, but i didnt see this option as I glanced at it..
We have an 8 inch automatic siphon. When we need to prime it, we use a shop vac. We just hook up a generator and plug in the shop vac, then tape it with duct tape to the Tee. This will get it going in no time. Available electricity is the key requirement here. A very simple solution though.

I have also taken an 8' length of pipe and slid it into the 90 where the water comes out. When the water starts filling the pipe, it travels up the 90 into this length, fills it up a bit - then POOF it will shoot out and the water will come pouring out. I dont know that you need this, but its worked for us.