Drawdown seal?

Any opinions on the use of drawdown seals? I don't know much about them and in my research I'm not find a lot of info. I am looking at putting in irrigation for my lawn, but when the well was drilled last summer the drilling company informed me that the well is probably not adequate for sprinkling due to a low recovery rate (10GPM). A family member of mine was in the same situation last year, and another local drilling company installed a drawdown seal. He has been very pleased with the results.

I have tried the Lemco (changed names several times since) draw down seal in several applications. They don't seal and they don't help. If someone has one and think it's helping, more power to them. If the well produces 10 gpm, it produces 10 gpm. The seal isn't going to help. Save you money.

bob...

I have installed a lot of lemco drawdown seals and have had good results with them. You can have good results as long as they are installed properly.

What type of well do you have?

SAM

Sammy, your not telling me that a Lemco drawdown seal can make a low flow well make more water are you? I don't know how you could put one in wrong. You connect it to the droppipe put a wire through each hole and tighten the bolts. The problem I see is when you put a vacuum on them is they leak.

bob...

Bob,
I have only installed lemco draw down seals on 4" screened wells with submersible pumps.I have never tryed them on any other application. They will leak if they are installed with polly pipe versus schedule 40 pvc.If they are installed using polly pipe the seal will sit crooked in the well. They will also leak if they are over tightened or if the rubber is misaligned exposing an open hole.You also have to make sure they dont sit in the well screen. I have had wells go from 4 gpm to 20 gpm using lemco draw down seals.

SAM

Tell us how the seal makes the well produce more water!

Raucina said:

Tell us how the seal makes the well produce more water!

Click to expand...

http://www.lemcoseals.com/

Theoretically, they allow a submersible pump to create a vacuum in the region of the pump so that more water will be induced to enter the casing from the aquifer.

They are very limited (even if they work as advertised) because the vacuum will soon cause the available Net Positive Suction Head (NPSH) to be reduced below the operating limit of the pump. The pump will cavitate and lose capacity if there is inadequate NPSH.

You would get better results by setting the pump about 20 feet lower in the well.

I have only applied lemcos in 4" wells where the screens are set iin fine sands that produce limited amounts of water. Setting the pump 20' lower most of the time is not an option with a screened well that needs a lemco. If setting the pump 20' lower was an option other developing methods would be applied and there would not be a need for a lemco.

SAM

I set the ones I used on Galvanized. I can see where poly would be a bad choice. I just never had any success with them, so I quit trying. Maybe they have a use on certain wells. Just not the ones I tried them on.

bob...

Speedbump,
i agree, they can be a pain, and i only use them as a last resort.

SAM

So a Lemco seal is just a seal that really SEALS? Seems like around here everyone must have a "Lemco" seal because they are using a split plastic or steel or cast 2 piece cap with a rubber type seal between. pipe fits tight, wire has ferrules to adjust to diameter, rope if used ditto. Then you tighten the 4 bolts and expand the rubber to squash everything tight. No air and no bugs and no water IN... thats what the county wants. Yet no one ever said that sealed cap would make more water from the well.

I use seals that have a unused port, usually 3/4" and place a pipe with cap in it - useful for chlorination. I have noticed a vacuum at this port in many wells, but in one, air would blow OUT. Go figure.

Drawdown seals are not well caps and shouldnt be used as a well cap.

SAM

sammyhydro11 said:

What type of well do you have?

Click to expand...

It is a PVC with a submersible pump. I believe it's 5". I don't have the spec's in front of me, I can post more info on the well later. Any tips for designing the sprinkler system to make due with 10GPM?

Design your zones to operate on less than ten gpm. Enough less that you will have 40 psi to operate them.

bob...

I would be happy with the ten gallons per minute unless you have a system in place that requires more water. I would size each zone a little under ten gallons per minute in the event the well slows down during a drought.

SAM

I agree with most of the opinions about Lemco Seals, but speedbump mentioned above that the name changed several times. When my dad started the company he named it Lowe Engineering & Manufacturing Co. The acronym becomes LEMCO. We have always called our seals Lemco Seals and that has never changed. When we were looking for a web presence, the name www.lemcoseals.com was available and I thought it was the best name that described our product. Then, about seven years ago, I decided to change the company name to match our website address, but only the company name changed. The full name of our product always has been Lemco Drawdown Well Seal. Simply put, it was designed to control drawdown. It does this by making an airtight seal above the submersible pump to stop it from sucking air. Actually, drawdown becomes a non-issue, because the Lemco Seal forces the pump to draw from the aquifer below instead of drawing down or lowering the water from above.

My Dad, Bill Smedley, Sr. gets credit for inventing the Lemco Seal, but the idea of making an airtight seal above the pump had been around for a long time. We heard some were wrapping the drop pipe with burlap and pine pitch to make a seal. Some of the drillers in our area were using K-Packers for seals, but from our experience, it was a nuisance trying to get the electrical wires for the pump through the packer and they didn’t seal very well since they were intended to seal sand and not air. Dad thought there had to be a better way, so he engineered a device that had the holes for the electrical wires with a rubber that has a larger diameter than the inside diameter of the well. That way, it has to fold up all the way around into a cup shape before it enters the well and that’s how it’s able to make an airtight seal.

Other ways of controlling drawdown were to restrict the flow or select a smaller pump, but these methods are unappealing when you’re trying to get as much water as you can. Lemco Seals are easy to use. Most sizes are made to screw into the top of the submersible. Then, the wire leads are run through the seal. When the nuts are tightened, the rubber squeezes around the electrical wires to make them airtight.

Sammyhydro11 mentioned the seal will leak if it isn’t installed properly. Our instruction sheet www.lemcoseals.com/instructions.html covers that issue. If the nuts are over-tightened or under-tightened, it can cause an air leak and the seal will not work. We recommend putting silicone caulk around the wire holes to help stop air leaks, but other problems exist too. Steel casing has a welded seam that can be hard to seal and if it’s an older well that has scale, it can be very difficult to get it sealed, but the rubber is soft and pliable enough that it should work, especially over a little time. We recommend putting a little water on top to help it. I’ve had some drillers tell me that they use a little Bentonite, but we don’t recommend that since that can make it difficult to pull the pump for repair.

Sammyhydro11 also mentioned the seal will leak if you’re using poly pipe, but my dad used a lot of poly pipe and it wasn’t a problem. He always used a safety cable when he used poly pipe. Since they fit so tight, the Lemco can be a little difficult to get down the well with this system, but dad’s trick was to hook up the electrical and momentarily turn the power on and off. That way, the pump pulls itself down the well.

Bob NH mentioned the seal allows “a submersible pump to create a vacuum in the region of the pump so that more water will be inducedâ€. I get more calls about using Lemco Seals to increase well production more than anything else. I already mentioned that restrictors are not necessary when it has a Lemco Seal, but larger pumps can be used to increase production. The Lemco Seal will not make a dry hole pump water, nor will it increase well production if the water isn’t available.

Where we sell most seals is for sand, screened wells where there is plenty of water, but there’s also excessive drawdown that is causing the pump to suck air. The Lemco Seal can help these wells produce more water by putting suction on the well.

Raucina mentioned using “seals that have an unused port, usually 3/4" and place a pipe with cap in it - useful for chlorinationâ€. The Lemco Seal has an extra ¼†hole for running polyethylene tubing with the electrical wires to the top of the well. Whenever the well needs to be chlorinated, all you have to do is open the top of that tubing and insert it into a jug of chlorine. When the pump runs, chlorine will siphon directly into the pump and screen area.

Bill Smedley, President
Lemco Seals, Inc.
www.lemcoseals.com

we drilled a to 1800 feet. the engineer speced out a casing size that does not exist for water wells and we were thus forced to use cheap imported mechanical piping. the pipe manufacturer did a poor job of threading the pipe and the casing separated at about three hundred feet. this depth happened to have some really nasty water that was not drinkable. we used a lemco seal to keep that water from enter the pump from above. this was a successful application until we could redrill the $100,000 well.

I agree with shack, that would have been a great use of a Lemco seal. But in using several seals in wells that wouldn't keep up with the pump, I found that air would soon find it's way down to the pump even with the seal in place. I even added water on top of the seal to try to keep it from leaking, but no luck. After a short time, the pump was again drawing down.

Don't get me wrong, I think they were a great invention and have a purpose in the water well industry, but as Bill said, they won't make a bad producing well make more water.

bob...