How to Get Threaded Shaft Out of Pump Impeller?

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liveaboard
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by liveaboard »

pumphouse interior.jpg
It has a 10 gallon pressure tank not visible in this picture.
9 irrigation zones; 2 are filtered and run about 200 drippers around the place, at about 30 psi.
1 is the orchard, which lets the pump run full flow at 5psi, while running the water around the filter screen for the drippers to clean it.
5 are for lawn sprinklers, which each run at about 25psi
The last is for daily backflush cleaning the pickup screen in the canal; a timer cycles the pump off while opening a line around the footvalve, so the pressure tank empties back into the canal through the screen. this cycles between 45 and 0 PSI.

This system wasn't really planned, it sort of evolved into it's current state.
Anyway, no pressure sensing setup will serve to protect the pump from dry running.

In a year or so the pump will hopefully be redundant, as I'm supposed to get connected to high volume, high pressure cheap irrigation water supplied by a new government funded system.
spro
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by spro »

Cool manifold and variable supply. Dry as a pin. It is easy to remark but a long work to get that right. I would keep the pic too. Even when it is changed, some folks know what was done for reasons.
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steamin10
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by steamin10 »

On a previous job we installed Dry Cut relays on all the motors. The plastic and ceramic shafts could be damaged if run dry, or the magnetic couplings broke free for some reason. ( The magnet fields pulsing against each other would heat up and melt the FRP plastic, and thermo plastic impellers.).

Simple in design, they have one leg of the motor run through a coil assembly to monitor the amps flow. If the amps drop below a certain set point, (motor unloads) the control relay opens to shut down the motor. Fairly simple latching circuit is all it is, and can be tuned for a certain amperage by the turns, and wire size for the relay. The inrush current, and slump after startup, more or less aids the coil buildup to pull in.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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liveaboard
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by liveaboard »

That's EXACTLY what I've been looking for, and asking for at local pump and electrical supply shops. I didn't know there was such a thing but I thought there had to be. They just look at me like I'm an alien.
Which of course, I am in Portugal.
Using the term 'dry cut relay', I did come up with one in Spain, but at $90 I have to think about it.
It's about the same cost as replacing a seal and impeller once; if I was keeping the system as is, I'd buy that for sure.
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SteveHGraham
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by SteveHGraham »

I like the hoses in the photo. I have been wishing I had hoses in some of the places where I know have uncooperative, rigid pipes. Maybe in future repairs I'll implement that notion.
Every hard-fried egg began life sunny-side up.
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steamin10
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by steamin10 »

Once we figured out the circuit parameters, we built 7 units, and installed them to interupt the sealing circuit for the 3 phase relays. We built the circuits using surplus parts from various salvage houses, as much of the requirements are generic. A trimming resistor allows some adjustment, so its not a big deal.

We never hurt a pump due to starvation after that, and it represented a major leap forward in run time, not to have to feed all those parts to a 6 inch capsule pump.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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liveaboard
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by liveaboard »

The hose is sold here by a swimming pool supply; my well stocked plumbing shop doesn't have it.
It can handle fairly high pressure and comes in the same od sizes as the black semi-rigid agriculture tube I use for the long runs, so I can use the inexpensive compression fittings made for that.
They call it pool hose.
That's all I can tell you about it.

Dave, I thought about building my own circuit, I've done such things in the past. I'm not very good at it so it tends to take me a long time, I only build my own electronic circuits when I can't do the job any other way.
This is the relay I found;
http://www.relaypump.com/Protectionrela ... pumps.html

This is an adjustable voltage regulator I developed for a little generator / AC unit I had in an RV; http://www.amsterdamhouseboats.nl/voltage_regulator.htm
It can control 2 alternators [or more] working in tandem, which makes for interesting possibilities. I needed to be able to turn down the voltage to prevent the engine from stalling when the AC was running and the big batteries were low, but turn it up when I wanted to use the torque of the little engine for battery charging.
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SteveHGraham
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by SteveHGraham »

The boating supply stores down here have hose suitable for the relatively low pressures in a sprinkler system. One of these days I'll give it a shot.
Every hard-fried egg began life sunny-side up.
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steamin10
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Re: How to Get Threaded Shaft Out of Pump Impeller?

Post by steamin10 »

Live aboad: There ya go. A magic switch for your problem. The one we built were clunky, because of the used /new parts, and overbuilt for cost. That was some 15 yrs ago or so, i think the market is served by purpose designed stuff in many sacles. Being not so popular, look at the surplus outlets, and wee what they have. Company spares show up when plants close or move, and the soup to nuts supply rooms unload all the shelves, as the parts are usually deemed not worth the move.

It is where I lived for a good part of my maintenance career. TTFN
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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