I need some pump advice.

[canuckamuck]

I have a tea field that I irrigate from a pond at the bottom. It is a fairly sharp incline and so far I have been irrigating to about 18m elevation. Yesterday my 6,5 Hp pump quit on me. I assume it is because I use it pinned at full throttle. I only got a season and a half out of it.

Anyhow, that was a 2" outlet pump. Now I am looking at a larger HP unit, because I hate to see a motor work that hard. Also I am thinking about going higher.But the pumps all come with 3" or 4" outlets for the bigger motors. Of course I don't want to re-plumb my field, so is it possible to simply reduce the 4" oulet down to 2" and carry on as before. Not on full throttle obviously.

[Thorgal]

You can repair the old one and purchase an identical one which you can install or connect them both in parallel. A 4"x2" reducer for a more powerful pump is not advisable.

To regulate the required pressure and volume, you can add a pump inverter + pressure regulator. Lifetime of you pump(s) will be much longer... Is interesting if you plan to reduce or extend your tea field surface irritation operations in the future.

ABB has ACS series pump inverters available in Thailand and are very reliable. Depends on budget and pump configuration.

On the other hand you can change or modify your piping system with one or multiple separation valves. You can split your field in multiple sections.

[Lamkyong]

wow did you get all that ? you didn't give detail on make of pump if cheap chinese/thai make you probably have done well

mind you not saying info given in previous post is not correct apart from the repair bit highly unlikely parts available

get yourself into a japanese made honda not cheap but good warranty and quality

and you can step up/down inlet/ outlet as required

[canuckamuck]

You can repair the old one and purchase an identical one which you can install or connect them both in parallel. A 4"x2" reducer for a more powerful pump is not advisable.

ImageUploadedByThaivisa Connect1455364307.569656.jpg

To regulate the required pressure and volume, you can add a pump inverter + pressure regulator. Lifetime of you pump(s) will be much longer... Is interesting if you plan to reduce or extend your tea field surface irritation operations in the future.

ABB has ACS series pump inverters available in Thailand and are very reliable. Depends on budget and pump configuration.

On the other hand you can change or modify your piping system with one or multiple separation valves. You can split your field in multiple sections.

There is no electricity out there, so I don't think I can use an invertor. My pump runs on gasoline.

The field has sprinklers at the bottom, but when that zone is closed, the water stays in the mainline which runs to a tank at the top of the field that holds about 5000 liters. The water then goes back down and runs through drip tape, I was thinking the 2" would be OK for the line going to the top. But maybe I am thinking wrong.

If you have 20 meters of head on a 4" pipe. Do you get more head if it is throttled down to 2"? If so, I could get water further up the field and therefore put more of the field into production.

[canuckamuck]

wow did you get all that ? you didn't give detail on make of pump if cheap chinese/thai make you probably have done well

mind you not saying info given in previous post is not correct apart from the repair bit highly unlikely parts available

get yourself into a japanese made honda not cheap but good warranty and quality

and you can step up/down inlet/ outlet as required

The broken pump was indeed a Chinese Honda clone. But I think it was too small and that is what killed it, I am sure it would have lasted much longer under different circumstances.

[farmerjo]

You could look at putting a motor on one of these.

Positive displacement.

http://www.pumpvr.com/joomla/index.php?option=com_content&view=article&id=49&Itemid=168〈=en

[canuckamuck]

Do you need a tak tak motor for those or do they use the Honda type too

[farmerjo]

Do you need a tak tak motor for those or do they use the Honda type too

Can use any type of motor.

The beauty of postive displace pumps are they pump high heads consistant at different flow rates so you can throttle back and still get your head

just less volume.

They come in different sizes depending of you flow needs

[Gsxrnz]

I don't believe you're pumping water uphill. This is Thailand - water flows uphill naturally.

[Thorgal]

You can repair the old one and purchase an identical one which you can install or connect them both in parallel. A 4"x2" reducer for a more powerful pump is not advisable.

ImageUploadedByThaivisa Connect1455364307.569656.jpg

To regulate the required pressure and volume, you can add a pump inverter + pressure regulator. Lifetime of you pump(s) will be much longer... Is interesting if you plan to reduce or extend your tea field surface irritation operations in the future.

ABB has ACS series pump inverters available in Thailand and are very reliable. Depends on budget and pump configuration.

On the other hand you can change or modify your piping system with one or multiple separation valves. You can split your field in multiple sections.

There is no electricity out there, so I don't think I can use an invertor. My pump runs on gasoline.

The field has sprinklers at the bottom, but when that zone is closed, the water stays in the mainline which runs to a tank at the top of the field that holds about 5000 liters. The water then goes back down and runs through drip tape, I was thinking the 2" would be OK for the line going to the top. But maybe I am thinking wrong.

If you have 20 meters of head on a 4" pipe. Do you get more head if it is throttled down to 2"? If so, I could get water further up the field and therefore put more of the field into production.

Yes, your head will change in function of your choice of discharge diameter. I could only find a chart for schedule 40 bar pvc piping. Your pvc pipes in the field should be 13.5 bar or below if you've used the typical blue pvc pipes available in Thailand.

It's just for reference because so you can match your required volume as per your piping system.

The quality of your water is also a parameter. Here again I provide you a sample picture to explain the principle. Water + mud/sand reduces pump lifetime. A simple sediment filter may be required for optimum conditions...

[sometimewoodworker]

If you have 20 meters of head on a 4" pipe. Do you get more head if it is throttled down to 2"? If so, I could get water further up the field and therefore put more of the field into production.

No you would have less head. Because the friction losses in a 2" pipe is significantly greater for the same length, for the same volume of water you need a higher velocity, and the higher the velocity the greater the friction loss.

There is a common misconception that if you reduce the size of pipe you will have a better flow.

It is quite possible that if you increased the pipe to 6" you would have a better head, however you need someone who understands fluid dynamics and can do the math.

This might help.

http://www.pumpfundamentals.com/tutorial3.htm

[NeverSure]

I'm surprised that no one has asked about a governor on that engine. OP says he runs the engine wide open. That shouldn't hurt anything if the engine has a governor which most small engines I have do. Even my lawnmower at full throttle won't actually run away or harm itself because the governor controls the speed of the engine.

I agree that sometimes the only answer is a positive displacement pump. I agree that a 4" pipe or otherwise bigger unit won't help in this application. Just remember that a positive displacement pump needs clean water. Other pumps, usually centrifugal pumps are often called trash pumps because they can handle some amount of dirty stuff.

If feeding from a tank above that's not itself pressurized, there won't be much pressure to a system that's just below it. Pressure will build farther down the hill unless the system is capable of using too much volume. It might require more valves and stations.

Cheers.

[1BADDAT]

Don't know all your details but it might be beneficial to use 2 pumps and have one half way up the hill to limit the Amount of work each one has to do

[NeverSure]

If he put a storage tank 1/2 way up the hill and pumped into that, it would make a difference. He could then pump out of that storage tank and the rest of the way up the hill and cut the lift needs in half.

Cheers.

[canuckamuck]

Thanks for all the replies. I am learning a lot. I am curious now about the positive displacement pumps. If they have better head, then I could get a 2" unit and just continue with my 2" pipes. And maybe make my storage tank into a base for a second pump to the top of the hill. What do these positive displacement pumps cost?

[Thorgal]

Thanks for all the replies. I am learning a lot. I am curious now about the positive displacement pumps. If they have better head, then I could get a 2" unit and just continue with my 2" pipes. And maybe make my storage tank into a base for a second pump to the top of the hill. What do these positive displacement pumps cost?

Better brands available here in Thailand for irrigation systems: engine+pump :

Honda

https://powerproducts.honda.th.com/dcs-wbs/product-type-display.action?productType.productTypeId=655361

http://www.thaivisa.com/forum/topic/823647-water-pumps/

Briggs & Stratton

http://www.briggsandstratton.com/sea/en/water-pumps

Depending on budget : Kanto and Jupiter...for asian brands...

[NeverSure]

I have assumed that your upper tank isn't pressurized. FWIW a pump will lift a lot higher if it's not under pressure but rather is just filling a tank. A factory pump should tell you it's lift capacity.

If you're going to need a second pump it will be more efficient 1/2 way up the hill than it will be at the top. That's because most pumps will push a lot better than pull.

It's too bad you can't get electricity out there. There are submersible well pumps that will push water from way down in a drilled well not only to the surface, but up into shower heads in a 2 story house and still maintain satisfactory pressure. They don't first have to pull water from the source, and they are positive displacement, often about 2HP motors. They are always 220v in the US at that hp rating.

[canuckamuck]

Neversure: The tank is like a swimming pool, water just drops in from the top and comes out the bottom.

Here's a high definition photo.

Thorgal: Thanks for all that, but those are centrifugal pumps, which is what I have. But now this thread has got me thinking that positive displacement pumps are the way to go. But I know nothing about them. Not what they cost, and not how to determine head height, or mating them with a particular horsepower engine. I would love some links about that.

[Gary A]

The positive displacement piston pumps powered by a small Kubota or Yanmar diesel will last many years. The small diesel engines are also much more economical to run. The piston pumps are also easily rebuilt.

[farmerjo]

Thanks for all the replies. I am learning a lot. I am curious now about the positive displacement pumps. If they have better head, then I could get a 2" unit and just continue with my 2" pipes. And maybe make my storage tank into a base for a second pump to the top of the hill. What do these positive displacement pumps cost?

Hi canuckamuck,

All local farm shops have them,check them out next time in town.

When inquiring,make sure you get a sales rep who knows what there talking about.I looked at some in a local shop and the guy kindly told me

look at the model number,not whats written on the top of the housing as it can be mis leading.IE 52,000 was written on housing and it was actually

good for 22m3/hr.(sorry didn't get to price as it didn't fit my needs)

I can't find a site i was looking at last night but think they are good to a max head of 100 metres so you wouldn't need a second pump half way up.

With the standard pump like you had,they are more a volume pump,not for high heads.

http://www.pumpschool.com/intro/pd%20vs%20centrif.pdf

.

[canuckamuck]

Wish I knew some of this 2 years ago, but good to learn it now.

[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.

[Gary A]

Solar powered piston pump;

http://www.bahtsold.com/view/12v-or-24v-water-pump-3000-l-h-130337

[Thorgal]

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.

[farmerjo]

I don't know about maintenance on a piston pump but if the Thai's use them they can't be to bad.

[Gary A]

I'm not a specialist and I can easily fix everything in the piston pumps. The only close fitting parts are the crankshaft and connecting rod. Those parts run in an oil bath and normally run for many years. The piston is not close fitting and it normally uses leather packing for seals. Water is actually a pretty good lubricant. Newer ones sometimes use rubber hydraulic seals. The check valves are normally rubber seals and can get dirt in them but the next cycle self cleans them. I doubt the pulsing will make problems but if it is a problem, it's simple to eliminate with a pressure tank using it as an air cushion. As with any type of pump, you should not be sucking mud through them. You should be using a foot valve with a coarse filter. Normal practice is to use an old inner tube to keep the foot (one way) valve off the bottom of the pond. That makes it easy to adjust how far below the surface that you draw the water.

[farmerjo]

Here's a suggestion for when the OP goes to town next,inquire at a farm shop about a VR pump,PVR 90 capable of 18-21 m3/hr.(2" inlet/outlet)

Inquire about a cheap chinese 8 horsepower motor which would create 5 horsepower at 2000 rpm (flat out 3500 rpm 8 hp)

Inquire about pulley size b section twin groove pulley.(don't know the rpm spec for max output of pump)

Also inquire about twin impellor and multistage petrol and diesel pumps,they may have a range.

It's going to cost either way so worth asking about the options.

Worst senario is walking away with what you started with that you know works.

[canuckamuck]

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

[Thorgal]

For local irrigation material I've found this website with prices and technical specs as reference :

- for pumps : all types as discussed previously: piston, rotational, ... If you want to build up pressure from remote location(s) : or for the lift :

http://www.arce-thai.com/category.php?id=1

- for sprayers : if you want to build up pressure close to you plantation: for sprinkling

http://www.arce-thai.com/category.php?id=2

[Gary A]

Thailand pump information;

http://www.pumpktc.com/index.php?action=home〈=en