I need some pump advice.

[fredge45]

Positive displacement pump, powered by a diesel engine is your answer. Trick is to put check valves into the pressurized line to reduce the outlet pressure at the pump.

I've pushed water for very long distances and very high head this way. You won't be getting any huge volume to your storage tank but just let it have time.

The close fitting moving parts of your positive displacement pump will cause maintenance problems, especially when the pump is handling fluids containing solids, as the particles can get into the small clearances and cause severe wear. Piston pump repair are (very) expensive and has to be done by a specialist.

The piston pump therefore, should not be used for slurries. OP uses non-filtered pond/rain water.

They give low volume rates of flow compared to other types of pumps. Which was the main issue of OP.

Your flow is pulsating and thus, not constant. OP requeres constant pressure for his irrigation sprinklers.

Figured he was using the pump as a lift pump... check valves work great to reduce total head pressure.

I used many different types of positive displacement pumps in my career in mining exploration... you can move some fairly large chunks of solids if you have the right setup internally in the pump. Use the centrifugal for the sprinking system, piston for lifting the water to a storage tank on top for feeding the drip lines.

[1BADDAT]

Tomorrow I should learn how bad my pump motor is. and whether it is worth fixing. It did work very well for my sprinklers, so I can see a scenario where I might run two pumps. One for sprinklers, and one for lift. However If I can get it all from one that would be the best.

There is very nice looking Briggs and Stratton 10HP in one shop I was in. That could run maybe two more tiers of sprinklers and then I could move my drip tape lines further up hill using the old 6.5 HP on a piston pump (or maybe the same 10HP). And I if I made a big enough reservoir up hill I could run sprinklers from there too as the hill is steep.

Anyhow I am considering all possibilities for the moment. I am not too concerned about the dirty water issue. In two years I haven't plugged a single sprinkler head. That indicates to me I am running reasonably clean water through the system. I do have the foot valve in a screen and elevated off the bottom by a floating 20 liter jug

Sounds like you have got some useful information and have a decent plan. Just remember that most of the work is done moving the water up the hill. If you can set up a reservoir up higher, that will greatly reduce the amount of work each pump will have to do to irrigate or transfer water.

[Gary A]

Double pump, double trouble and double use of benzine. If it were me, I'd bite the bullet and spend a little more money on a diesel powered piston pump. This type of pump is able to push much more water uphill that an impeller type pump and best of all, it will last a lot longer and use a lot less fuel. We have a very good bore hole and use a one HP submersible pump. That farm is off the electrical grid so we use a 5,000 watt benzine generator to power the pump. Unfortunately it takes a lot of benzine to pump that water. In three years, I have spent 8,000 baht on generator repairs. The water from the submersible goes through a grid of open pipes so there is no tank or sprinklers. The submersible pump is 36 meters down the bore hole so options are very limited. Where possible, we use an 11 HP diesel kubota tak tak to pump from the ponds. It pumps a 4 inch stream of water from a centrifugal pump but there is no uphill push needed. It pumps a lot more water on a lot less fuel. Don't make the mistake of buying an air cooled diesel. The life span of air cooled diesels is less than a benzine engine. When/if the submersible pump fails, I will change to a solar powered DC pump. That is free pumping when the sun shines. When/if the benzine generator dies, it will be replaced with a Kubota or Yanmar water cooled diesel. It would be my luck that if I replace the benzine generator, the pump will fail shortly after. There are always decisions and gambles to make. I did try a piston pump that belonged to a friend for the bore hole but when the water level in the casing dropped, the pump lost suction. The only other option was a submersible.

[1BADDAT]

Double pump, double trouble and double use of benzine. If it were me, I'd bite the bullet and spend a little more money on a diesel powered piston pump. This type of pump is able to push much more water uphill that an impeller type pump and best of all, it will last a lot longer and use a lot less fuel. We have a very good bore hole and use a one HP submersible pump. That farm is off the electrical grid so we use a 5,000 watt benzine generator to power the pump. Unfortunately it takes a lot of benzine to pump that water. In three years, I have spent 8,000 baht on generator repairs. The water from the submersible goes through a grid of open pipes so there is no tank or sprinklers. The submersible pump is 36 meters down the bore hole so options are very limited. Where possible, we use an 11 HP diesel kubota tak tak to pump from the ponds. It pumps a 4 inch stream of water from a centrifugal pump but there is no uphill push needed. It pumps a lot more water on a lot less fuel. Don't make the mistake of buying an air cooled diesel. The life span of air cooled diesels is less than a benzine engine. When/if the submersible pump fails, I will change to a solar powered DC pump. That is free pumping when the sun shines. When/if the benzine generator dies, it will be replaced with a Kubota or Yanmar water cooled diesel. It would be my luck that if I replace the benzine generator, the pump will fail shortly after. There are always decisions and gambles to make. I did try a piston pump that belonged to a friend for the bore hole but when the water level in the casing dropped, the pump lost suction. The only other option was a submersible.

Using 2 pumps does not mean that you will use twice the benzine. The amount of fuel burned is related to the work done, and both will be sharing the work. Having two pumps will also make things more flexible if one breaks, as the other could be moved to do either job.

You are correct that diesels are more efficient and should last longer, but I am not so sure on the reliability of a piston pump for this application.

[Thorgal]

Tomorrow I should learn how bad my pump motor is. and whether it is worth fixing. It did work very well for my sprinklers, so I can see a scenario where I might run two pumps. One for sprinklers, and one for lift. However If I can get it all from one that would be the best.

There is very nice looking Briggs and Stratton 10HP in one shop I was in. That could run maybe two more tiers of sprinklers and then I could move my drip tape lines further up hill using the old 6.5 HP on a piston pump (or maybe the same 10HP). And I if I made a big enough reservoir up hill I could run sprinklers from there too as the hill is steep.

Anyhow I am considering all possibilities for the moment. I am not too concerned about the dirty water issue. In two years I haven't plugged a single sprinkler head. That indicates to me I am running reasonably clean water through the system. I do have the foot valve in a screen and elevated off the bottom by a floating 20 liter jug

Another good summary that endorses most of the topics that were discussed in this thread :

http://www.dpi.nsw.gov.au/agriculture/resources/water/irrigation/systems/pumps/selecting

How many rai is your plantation ?

[farmerjo]

When selecting a pump,would i be right or wrong with this summary for my own benefit.

I have an 18 metre head and i want 4 bar of pressure at the sprinkler head to get the best performance out of it at x amount of gpm.

I have calculated my pipe size and will lose 2 bar through friction losses.

Am i right to assume i'm now looking for a pump that will give me x required flow at a head of 78 metres?give or take for atmospheric pressure.

Thanks

[canuckamuck]

Going into to town tomorrow to pick up the pump motor. The shop fixed it instead of giving me an estimate. But it was only 600 baht so no problem. No idea what the problem was, I will find out tomorrow perhaps.

Also I will be pricing out the other options that have been bounced around here.

@Thorgal, We only have about 5 rai into tea, with three rai higher up that we would like to plant to tea as well. And there are 100 date trees and 50 Macadamia trees in there as well. If all goes well we might do the same thing on another piece across the valley.

[1BADDAT]

When selecting a pump,would i be right or wrong with this summary for my own benefit.

I have an 18 metre head and i want 4 bar of pressure at the sprinkler head to get the best performance out of it at x amount of gpm.

I have calculated my pipe size and will lose 2 bar through friction losses.

Am i right to assume i'm now looking for a pump that will give me x required flow at a head of 78 metres?give or take for atmospheric pressure.

Thanks

You were pretty close. The answer I got was 79.2 Meters of head or 7.76 bar. Atmospheric pressure is negligible, but it actually works in your favor very very slightly.

[farmerjo]

When selecting a pump,would i be right or wrong with this summary for my own benefit.

I have an 18 metre head and i want 4 bar of pressure at the sprinkler head to get the best performance out of it at x amount of gpm.

I have calculated my pipe size and will lose 2 bar through friction losses.

Am i right to assume i'm now looking for a pump that will give me x required flow at a head of 78 metres?give or take for atmospheric pressure.

Thanks

You were pretty close. The answer I got was 79.2 Meters of head or 7.76 bar. Atmospheric pressure is negligible, but it actually works in your favor very very slightly.

Thankyou

[BSJ]

The wife and I bought a Chinese Honda and it's not a bad unit. Was about 900 baht cheaper than the red and black Thai model....which has a lot of Chinese parts anyway! Got about 100 hours on it now.

Starts first pull even when cold and I have to use the choke. Got to run it at full throttle to suck the water up which can take 2 or 3 minutes which is annoying. Once water is flowing I throttle back to half throttle and it will run for 6+ hours on a tank of 91. Plus I have less problems with pipe and hose blowouts at half throttle!

I'll drill a hole in the suction pipe at the pump end, tap it and put a plastic screw cap in to have a way of priming the tube before I start pumping. The none return valve at the other end will stop the water getting away.

[canuckamuck]

For those who may wonder how I got on. I got the pump back and it works fine. Its back in action. I figured out today I am getting about 10,000 litres an hour at 18 meters elevation. That's not bad. So I am going to keep the configuration as is. I am however going to get a piston setup for the upper field. I think that is about 30 meters elevation.

[canuckamuck]

The wife and I bought a Chinese Honda and it's not a bad unit. Was about 900 baht cheaper than the red and black Thai model....which has a lot of Chinese parts anyway! Got about 100 hours on it now.

Starts first pull even when cold and I have to use the choke. Got to run it at full throttle to suck the water up which can take 2 or 3 minutes which is annoying. Once water is flowing I throttle back to half throttle and it will run for 6+ hours on a tank of 91. Plus I have less problems with pipe and hose blowouts at half throttle!

I'll drill a hole in the suction pipe at the pump end, tap it and put a plastic screw cap in to have a way of priming the tube before I start pumping. The none return valve at the other end will stop the water getting away.

008.jpg

Do you have a good foot valve at the suction end? My pump generally gets suction immediately or with a minute or two. Unless I haven't used it in a long time And then it can take a few minutes at high revs like you say.

Also, even the slightest leak on the intake line will bring air into picture, greatly increasing the amount of time to get it primed.

On the farm we used to always have the outgoing pipe raised up higher than the pump, even if just for a few feet, so that there was water trapped against the pump and it wasn't necessary to prime the pump usually. But then you have to know if the foot valve on the pump itself was holding.

Your pump looks very similar to mine, but I think you have a 3" unit.

[farmerjo]

Here is a picture of a little solar power set up my brother uses on his farm in Australia,only does about 1200 litres a day.

But more to show you the pressure tank.

[ThaiKneeTim]

Progressive cavity pumps are simple to operate and maintain, they're self priming and will pump slurry or water.

As to whether they are available in Thailand is a question I can't answer!

[canuckamuck]

These piston pumps. Typically I see they list volume and head. eg 20,000 litres an hour, and 40 meters of head. 2" inch outlet.

How do I determine what kind of flow it will give at 40 meters. Is it all down to friction loss or is there some other factor???

I know now that the next location for a storage reservoir in my field is 90 meters from my pond and at an elevation of 35 meters above the pond.

What kind of pump should I use? Size of pipe is undetermined.

[farmerjo]

These piston pumps. Typically I see they list volume and head. eg 20,000 litres an hour, and 40 meters of head. 2" inch outlet.

How do I determine what kind of flow it will give at 40 meters. Is it all down to friction loss or is there some other factor???

I know now that the next location for a storage reservoir in my field is 90 meters from my pond and at an elevation of 35 meters above the pond.

What kind of pump should I use? Size of pipe is undetermined.

The pumps capacity will be determined by the rpm,head and hp supplied as well as pipe size.

What do you want to achieve, filling a tank in a certain amount of time.?

[canuckamuck]

These piston pumps. Typically I see they list volume and head. eg 20,000 litres an hour, and 40 meters of head. 2" inch outlet.

How do I determine what kind of flow it will give at 40 meters. Is it all down to friction loss or is there some other factor???

I know now that the next location for a storage reservoir in my field is 90 meters from my pond and at an elevation of 35 meters above the pond.

What kind of pump should I use? Size of pipe is undetermined.

The pumps capacity will be determined by the rpm,head and hp supplied as well as pipe size.

What do you want to achieve, filling a tank in a certain amount of time.?

Well yes that is the main part, but in retrospect I suppose it doesn't matter too much how long it takes to fill a tank, As long as I know how long it takes and can work around it. But sprinklers higher upfield are not off the table if the pump performance is up to it.

So when I buy a pump, how do I put the pieces together. Start with a pump and then get a motor and pulley size to get the result needed? Do people in shops know usually how to calculate that?

[farmerjo]

These piston pumps. Typically I see they list volume and head. eg 20,000 litres an hour, and 40 meters of head. 2" inch outlet.

How do I determine what kind of flow it will give at 40 meters. Is it all down to friction loss or is there some other factor???

I know now that the next location for a storage reservoir in my field is 90 meters from my pond and at an elevation of 35 meters above the pond.

What kind of pump should I use? Size of pipe is undetermined.

The pumps capacity will be determined by the rpm,head and hp supplied as well as pipe size.

What do you want to achieve, filling a tank in a certain amount of time.?

Well yes that is the main part, but in retrospect I suppose it doesn't matter too much how long it takes to fill a tank, As long as I know how long it takes and can work around it. But sprinklers higher upfield are not off the table if the pump performance is up to it.

So when I buy a pump, how do I put the pieces together. Start with a pump and then get a motor and pulley size to get the result needed? Do people in shops know usually how to calculate that?

Firstly you need to know what you want to achieve,i've just spent the good part of 4 weeks trying to design a sprinkler system and thought my 12 hp engine would do the job when i actually need a minimum of 50 hp.

Suggestion,work out a flow rate required for sprinklers and take into consideration head required.Then pipe size for pressure loss.After you have determined that you have to look for pumps specific to your needs within a pump curve and there hp requirements.

When you start to talk 35 metre head your average 2 or 3 inch centrifical pump is out of limits unless it's a fire pump,higher pressure but less volume.

Find out what the maximum rpm is for the piston pump 1400rpm? and at what hp.The pressure should remain the same.

There is a pulley calculator on the net to determine pulley sizes rpm of drive and driven.

If you can tell us exactly what you want,may be able to help out with recommendations.(just fill a tank in x amount of time or run 10 sprinklers.)

[canuckamuck]

First I need to look at sprinkler specs. I'll get back to this thread in a while.

[Gary A]

All the farmers around here use a tak taks to run their pumps. The pulleys on my 11 HP tak tak are maybe about 3 inches or a little bigger in diameter. They have three belt grooves. The tak tak itself uses one groove to run itself and the pumps run off another groove. The pulley on the piston pump is quite a lot larger and the impeller pump pulley about the same size as the tak tak pulley. Changing the piston pump pulley would probably be difficult and expensive because they are made of heavy cast iron. I think the pumps are designed to run off the standard small diesel pulleys. My brother in law has an 8 HP tak tak and mine is 11 HP. His 8 HP seems to run the impeller pump as well as my 11 HP. Some of the farmers pump water a half kilometer or so from government reservoirs and they normally use piston pumps especially if they have to pump up a grade. I'm always amazed at how much water the impeller pump can move.

[canuckamuck]

I've always assumed the tak tak motors would be expensive, but I have never priced them out. Do you know what they go for?

As for pulley changing, usually it is done by loosening a set screw and removing a keyway.

[Gary A]

The pulley on the Kubota is bolted to the flywheel with three bolts. Not difficult to change. I honestly don't remember how much we paid but they are expensive. Chinese built are a lot cheaper and seem to hold up quite well. They look nearly identical.

[Gary A]

My wife said that just the 11 HP Kubota diesel cost about 38,000 baht.

[canuckamuck]

My wife said that just the 11 HP Kubota diesel cost about 38,000 baht.

Ouch. Some shops got 5.5 HP diesel units for 6-7000 baht.

[farmerjo]

http://www.blocklayer.com/pulley-belteng.aspx

Here's a link for your pulley sizes,just play around with the figures.

On the cost of diesel engines,my single cylinder yanmar 14hp with electric start was about 56,000 6 or 7 years ago from memory.

Not cheap but i use it for much more than just pumping water as most are.

[Gary A]

My wife said that just the 11 HP Kubota diesel cost about 38,000 baht.

Ouch. Some shops got 5.5 HP diesel units for 6-7000 baht.

If you decide to buy a diesel, make sure it is water cooled.

[canuckamuck]

Update:

Here's where I am at. I have found a piston pump I like. It is a double piston unit and it puts out 37cubic meters an hour. 10 more than my current pump. What I need to decide on is how to power it. The guy who sells the pump has some Honda motors around but only up to 5.5Hp. He tells me the Honda can power that pump no problem. Even though I said I don't want to run the pump flat out all the time.

I went to another shop and they have some lovely Briggs and Strattons. They have a 6.5HP and a 10HP. They tell me the 6.5 can do it but it will have to run flat out, whereas the 10 HP can do it at a slower RPM.

Of course they both want the sale and they want to sell the most expensive one they have.

Anyhow I already have a motor which has equal specs to the 5.5 Honda on my other pump. And if the Honda can do it so can mine (probably). But if mine can't do it, I have to go bigger. If the 6.5 HP can't do it I am out some more cash, and if 6.5 can do it and I buy the 10, then I paid too much.

Also, I am worried that if I get the 10 and configure the pump to run at lower revs, what happens if someone opens the motor full throttle? will it blow up the pump?

Any advice would be appreciated.

[farmerjo]

What are you trying to achieve with the pump and does it have a name and model number.

[canuckamuck]

Run sprinklers at lower elevation and fill tanks higher up. 40 meters elevation.

The current sprinkler line is only 13 heads but I do not know what diameter the nozzles are. The 5.5 HP pump I have runs at near full throttle when I use that line. It is rated at 27 cubes per hour.

I would be either sprinkling or filling tanks, not both simultaneously.

[canuckamuck]

I do not remember the pumps make or model. I will try to get that later.