Vacuum Pump Needed

[cleatus]

I was thinking PVC ball valve each end, tee with 2" riser with ball valve at top. Use small hose to fill 4" then shut off 2" valve, open others turn on pump. Just what I have done in past.

 

[mopacman]

you might try running a vacum line from the intake of a gas engine. they have ben used to pump septic tanks.....Larry

 

[DocHeb]

I presume what is happening is that the suction pipie empties after the pump turns off. Can you install a check valve at the end of the pipe to keep the pipe full of water?

 

[have_blue]

Yea Henro, it is a siphon. Priority 1 is to not ruin my big pump. Priority 2 is to not use it at all. It's a real back breaker.

I've proofed it out already, and the 4" pipe really moves some water. I used 2" hose before, and it worked great, but was too slow. The 2" had only a fraction of the 4" volume, so it was easy to prime.

I thought of the reservoir idea too, but it would take a lot of water! You can pour a 5 gal. bucket into the 4" pipe, and it's gone in a flash. I priced some check valves, and they cost more than a little 1" gasoline pump!

 

[WhiteRock]

I am not sure I can visualize your entire scenario, but have you thought about this?

Add a re-circulating circuit to the pump (this will be design on the fly /forums/images/graemlins/grin.gif). On your 2" inlet put a tee with a 3/4" reducer. Plumb this into a small reservoir (maybe your 5 gal bucket) filled with water. You will need a valve here. Start the pump. Route the pumped water back to the reservoir. The 3/4" restricter will cause a vacuum in the 4" pipe while keeping the pump lubricated. When the air stops on the output of the pump, you should be primed. Shut off the 3/4" input valve.

The 3/4" restricter's purpose is to starve the pump forcing it to pull air from the 4" pipe. Priming with water will make it an efficient vacuum pump. You might need to go with a smaller restricter.

This is just an idea. I have not validated this design. It should be cheap. You will probably have better ideas on the reservoir and plumbing. Two valves would be better (one on output and input). Then you might be able to use a piece of 4" pipe for the reservoir and leave a hole in the top for filling and an air vent. When the air stops shut them off. If you shut of the output first, you should have water for the next time.

I hope this make some sense....

 

[have_blue]

Hi Whiterock,

Well... you see, I' trying to avoid lugging on that 150# pump. My back is already sore. I want something cheap so I can just leave it down at the pond.

Your idea would no doubt work. I have to be careful about having multiple valves and other complications, cause it would have me jumping all over the place when the pump suddenly primed. /forums/images/graemlins/smile.gif

Bouncing your idea around, I'm thinking about threading a 1/2" pipe hole in my 2" hose fitting near the pump inlet (suction side) and stuffing a hose tightly into it from my garden sprayer. Keep shooting water to keep the pump full, and it should prime real quick. When it primes, I simply turn a valve, and voila! The siphon is going!

I still rather a 12v bilge pipe or a honking big manual bilge pump instead of lugging around that Red Lion back breaker. /forums/images/graemlins/smile.gif

I'm open to any ideas. The thundershower season is coming, and I need to keep my pond dry so I can work in it.

 

[WhiteRock]

<font color="blue">trying to avoid lugging on that 150# pump </font>

I thought the pump stayed put. /forums/images/graemlins/confused.gif I didn't think my suggestion required the pump to move, but I know I am probably confused.

I think your threading idea should work fine. I think the hose attachment must not have an air leak, or the pump will never prime. I was trying to figure a way to catch and re-circulate the priming water in the event a lot of water was required to pull the air out of the long 4" line.

It is not clear to me how the bilge pump idea will work. With no check valve the water will just run back into the pond. /forums/images/graemlins/confused.gif Would you just fill from the output side of the pump?

 

[Dirtnut]

put a foot valve on the end of your pipe like is on a well pump system and your pipe will always be full. when you hook your pump up you can fill the whole pump system up no air no primeing.

 

[have_blue]

WhiteRock,

I just ordered a manually operated bilge pump rated at 15GPM. I don't need a check valve if the pump will hold most of the air I pump on each stroke. If not, well, I'll have to get a little tiny foot valve or flapper valve. They have them locally.

Remember, I'm pumping air. when water comes out of the pipe, I'm finished. I just turn off the big valve coming out of my 4" pipe and it starts siphoning.

I'll post a picture to cut some of the confusion. /forums/images/graemlins/smile.gif

 

[Soundguy]

What about putting a foot valve on the end of the pipe in the lake.. ( like on an above ground jet pump ) and then you won't loose prime in the first palce? Alternately.. if it did leak down, you could prime the pipie with a bit of water from a bucket.. etc

Soundguy