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Forum Index : Other Stuff : Need some water pump advice.
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
OK, another question for those in the know. I want to put together a water pump using some bits I have lying around. It would need to pump water up about 10 meters max, about 20 psi outlet pressure, and suck up a couple of meters at most. I have a old Vickers 1hp motor. It works well, starts easily. 
I rigged it up to a old centrifical pump, also in pretty good condition. Ratio was about 1:1.5, so the pump was running slightly faster than the motor. With the motor running I primed the pump with a garden hose connected to the water mains, and then put the hose into a bucket of water to see how well it pumped the water out. Results were dismal, no more than a trickle. So I need to rethink it. I guess I could be doing two things wrong, not enough pump speed, and/or, pump outlet at side, leaving a air pocket in the top 1/3 of the pump. I did prime the pump, but it would still have the air pocket, and I guessed once the pump was running the air would be driven out, maybe not. I can fix that. Maybe I need much more RPM, I do have a bigger pulley I can machine to fit the motor, making it about 1:4 ratio. I also have a little gear pump, which I've used to pump water before. Would it be a better option? 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn The centrifugal pump would be a better option as a gear pump is low out put and wears out quickly as well. Sounds like an air pocket could be the problem need to have the outlet on top, and needs to be 3000 rpm suction lift with a good foot valve max 3 meters and may need the packing redone as it can suck air there and reduce efficiency, I have a little pump like that and it would pump 300 to 1000 gallons an hour depending on head. All the best Bob Foolin Around |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thanks Bob, I'll rotate the housing and gear it up. Let you know how it goes. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Well that was a waste of time. This pump must need a lot more RPM that the old Vickers can provide, even with a stepped up drive. The pump impeller is an odd shape, nothing like a car water pump impeller. It looks more like a disk brake, with only 4 internal slots. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn Must be something wrong with the impeller as these little pumps normally do a good job. Have you checked for wasp nests in the impeller of excessive corrosion as a closed impeller can block easily. All the best Bob Foolin Around |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah checked it for blockages, and if I connect up the garden hose it passes water easily. Checked for correct direction of rotation about 10 times even. I tried reving up the motor, but got little more than a trickle and I could easily stop the flow with my finger. I suspect the pump needs a lot more RPM. 
I need to get some paying work done, so will look into it in a couple of days. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hi Glenn, With no pressure ie: you can stop the flow by your hand. My guess is air is passing by the gland packing, now bearing shops should sell the gland packing by the meter or source some for you. also there are two ways to install gland packing the right way and the bodgy way. The right way is by cutting a 45 degree end so when the gland packing is installed and crushed it will fully seal. Too many times I have to replace gland packing only to find either square ends of one continuous coil which will cause air to pass of a leak every time. For the small expense of the gland packing it may to change it out then try again with the current setup. Regards Bryan |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Glenn, waterpumps 101 is like a merit badge for farmers. If you are not careful next thing you know you will be endlessly banging on about the weather, watchin Landline on the telly and driving with your arm out the window.  its a slippery slope!I'm confused, no wait... maybe I'm not... |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah well, I'm about to throw this pump over the back fence. Thought about Bryans suggestion, and adjusted the gland to make sure it wasnt leaking. I also blew some air into the system and checked for any leaks around the pump with soapy water. All good. Tried once more, still pathetic. I've had the cover off, impella looks fine. I figure, even if I get the thing working, its so sensitive to RPM/air/whatever, its going to let me down whenever I go to use it. Going to plan B, the gear pump. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hi Glenn, I have repaired that type of pump before with the disk brake type impeller and the pumps were directly connected to a 4 pole 3 phase motor via a flexible coupling. Gland packing over time will harden where it runs on the shaft and no matter how much you tighten the nuts air can still pass. Now before you throw over the back fence carefully take out the packing and see if you can turn it around so the outer edge will run on the shaft. Now when you put back together leave the packing slightly loose so water can leak past then evenly tighten the bolts until the leak stops. Then after a bit of run time tighten the bolts a bit more, this will ensure the gland packing is seated properly. Now also if your only using a garden hose for the input the low volume of water could be all thats causing the problem. It may pay to take it out to your block and try it in the river. Anyway if it still don't work atleast you'll have an anchor for another future river project. Cheers Bryan |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
if it does not pump water when the garden hose is giving you positive pressure on the intake, then the impeller is blocked with crap on the inside. it will need to be poked out from the outer towards the centre as there is a taper in the chamber. If it pumps with a positive head then, to make it lift as Bob says, it needs a footvalve and screen (and the footvalve needs to be vertical in the water) on the suction hose to help get it started. we all take shortcuts with priming if we can get away with it. The way it is done by the book is with a small daiphram hand pump on the delivery side. shut delivery gate valve open line to hand pump suck water through the pump close line to hand pump (so it doesn't blow up with water pressure) start motor open delivery gate valve look smug with a bit of technique you can dump the footvalve up and down and don't need to bother with proper priming these pumps are a low pressure/high flow pump they work best with little or no restriction to the output so if you want less water you throttle the motor right back rather than screwing the tap off, should be no problem with RPM. I'm confused, no wait... maybe I'm not... |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
Hi Glen what i was thinking is possible that is too much gap clearest between impella and pump housing and dont throw this pump over the back fence as someone might come around and knock your door with bandage on his head 
Dwyer |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn Looking at your picture I think the input hose is to small mine had a 1 inch suction pipe and a 3/4 inch discharge pipe, I think a small pipe on the inlet would cause it to go into gravitation. Looks a good little unit so do not give up on it, if you need a hand with it bring it to my place and I will give you a hand with it. All the best Bob Foolin Around |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I think you may be right Bob. One thing I noticed yesterday, but it didn't click at the time, was the water coming out was very warm. Reading on the internet last night, cavitation heats up water! And I also read a sudden change in diameter from small to large at the impeller inlet can casue cavitation, its a common mistake made my people ( like me ). The inlet is 3/4, I'll grab some hose to suit and give it another go. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Glen, Closed inpellor pumps are senstive to proper clearances, and like it has already been stated, either bad packing or clogged fins...or both, also it won't pump with air in it. I have used a masson jar hooked to the vaccume of my pick-up truck to draw the head up and prime the irrigation pumps...works a treat, just look at the glass jar and when you start getting water its primed. Done this hundreds of times. Best of luck with it...fustration is a tempory thing, you'll get it running. Kind reguards...Mac46 I'm just a farmer |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hi Glenn, Now as you have the acreage if you haven't got any try and grab a pallecon or two( these are those 1000 litre containers in a frame.) you will find they will come handy on the block and they will be purfect for testing that pump. now personally I would set it up at your desired drop in height then hold the 3/4" pipe higher than the pump then run water from the outlet to dispel all the air. Hook it up to the pallecon and fire the pump up and see just how long it will take to empty that 1000 litres. Those closed impeller pumps can be finicky as stated before and I'm sure it isn't beyond you to machine up a new open impeller on your cnc and retro fit that to the pump. Hell even Trev could cast you one if you asked nicely. With my Honda water pump that I use to pump water up my header tank it will only run on idle and I have found it is more economical to run and it takes only about 10 -15 minutes longer to pump 2,000 gallons up a 40' + head. Regards Bryan |
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Hi Glen, Here is something that may help. Your Vickers Engine is plenty fast for that pump. --------Cheers, Roe 
Time has proven that I am blind to the Obvious, some of the above may be True? |
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| johnmc Senior Member  Joined: 21/01/2011 Location: AustraliaPosts: 282 |
Hi Glen. Your pump and motor should pump water,main problem is usually air in the suction side of the pump,these pump almost always need a foot valve on the end of the suction hose to make sure that pump can be bled of air. cheers john johnmc |
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GreenD88 Senior Member Joined: 19/05/2009 Location: United StatesPosts: 104 |
Most centrifugal run around 3600 rpm and are direct drive. What you have is a Enclosed type and the most efficient. Either your sucking air in on the suction side or not priming enough. Could be bad seals, or leaky garden hose? But you definately need a check valve on the end where your sucking up of it's very far. How deep are you trying to pull water? And for pumps we have a 5 to 1 rule where we don't have any bend in the suction side any closer than 5 pipe diameters from the suction inlet on the pump. so 3/4" you need at least 3.75" pipe between the pump and a elbow. This prevents cavitation if you don't have a suction diffuser. Licensed Master Plumber / EPA 608 Universal License / 410a Safety Certified / Medical Gas Brazer/Installer |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Well finally got the little pump sorted. Using the gear pump, and changed the pulley ratio's, its now pumping pretty good, about 250 meters through a 1 inch poly pipe. Filled a 500 litre tank in about 20 minutes. 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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