PUMP PIPES

[carlyai]

FYI

A while back, I read on the forum somewhere that there are different thicknesses of that blue plastic pipe used to connect to pumps.

Also that if the pipe that was used to connect to the pump had been laying in the sun for a while they go brittle and can collapse under pump pressure.

Found that a bit hard to believe, but accepted it as fact.

These are snaps of my farmer friend's (must have the regulation black tubing helping things work), jet pump that failed yesterday.

[Crossy]

Ouch.

Those pipes must have been the cheapest of the cheap to collapse like that.

[Sophon]

Judging from the last pic, it doesn't seem like the pipes line up as they should. Maybe when they installed them they heated up the pipes to make them bend, in order to reach the pump? That would explain why they eventually collapsed.

Sophon

[lopburi3]

Indeed that appears to be the likely cause - Thai like to use heat rather than line things up or buy elbows. Expect was in hot sun a long time and then severe vacuum of pump pulled it in.

But yes - there are various grades of pipe so buying the thick wall type can be cost effective for the long run. If a contract they will provide the cheapest available (in Conakry, Guinea locals plumbed a house for rent to US Embassy with plastic conduit - did not survive first pump start).

[Naam]

Judging from the last pic, it doesn't seem like the pipes line up as they should. Maybe when they installed them they heated up the pipes to make them bend, in order to reach the pump? That would explain why they eventually collapsed.

Sophon

they heated them up and left the pipes as they are. no such thing like a PVC-pipe collapsing, it's nothing but Thai engineering at its best

disclaimer: i admired the work of the contractor who did my pool piping and his bending by heating up pipes.

[carlyai]

Judging from the last pic, it doesn't seem like the pipes line up as they should. Maybe when they installed them they heated up the pipes to make them bend, in order to reach the pump? That would explain why they eventually collapsed.

Sophon

they heated them up and left the pipes as they are. no such thing like a PVC-pipe collapsing, it's nothing but Thai engineering at its best

disclaimer: i admired the work of the contractor who did my pool piping and his bending by heating up pipes.

You could be correct, but when I was reading up on pumps, a while back, it was mentioned that suction could cause thin walled or brittle pipes to collapse.

My wife noticed the brother-in-law's bore pump running continuously this morning when she went out. When she returned from giving all our food away to the Monks, she noticed the pump still running and the plastic very very hot, so she turned the pump off.

The pump and the piping was installed by the brother-in-law who did not heat up the pipes to install them.

I still don't know how he got the jet pump to work as one of the pump inlets sucks and the other blows. (Some of the words in that last sentence bring back memories of my early single days in Bangers.)

The pipes have collapsed due to the suction and heat generated I would suspect.

[Delight]

Fluids will only move from A to B if A is high pressure zone and B a low pressure zone.

If the feed into a pump (A ) is at atmospheric pressure –then (B ) must be at a lower pressure i.e a vacuum.

Water under a vacuum condition will tend to partially vaporize

The water is ‘stretched’ producing minuscule sized bubbles.

When these bubbles are exposed to the pressure at the outlet port of the pump –they will implode. This condition is known as cavitation. This typically damages both the pump and the inlet pipe (unless the pipe is metallic).

Also the smaller (and longer) the inlet pipe work –the more friction is experienced within this pipe. This means that the vacuum has to increase –thus worsening the situation.

It is wise to think of the inlet pipe work -to a pump-as a funnel i.e large pipe work feeding the smaller inlet port.

So if the port is 25 mm then use 38 inlet pipe work –reducing with a tapered fitting at the 25 mm port.

For certain this will reduce or possibly eliminate cavitation.

A reduce pipe on the outlet will typically not harm the pump. However a smaller pipe will mean that the pump is working at a higher outlet pressure than would be the case with a larger outlet pipe. The net result of that is simply higher energy consumption i.e. higher power bills.

The pipe work on the picture is a joke.

A cheap job with a long term high cost.

Edited September 22, 2015 by Delight

[sappersrest]

Fluids will only move from A to B if A is high pressure zone and B a low pressure zone.

If the feed into a pump (A ) is at atmospheric pressure –then (B ) must be at a lower pressure i.e a vacuum.

Water under a vacuum condition will tend to partially vaporize

The water is ‘stretched’ producing minuscule sized bubbles.

When these bubbles are exposed to the pressure at the outlet port of the pump –they will implode. This condition is known as cavitation. This typically damages both the pump and the inlet pipe (unless the pipe is metallic).

Also the smaller (and longer) the inlet pipe work –the more friction is experienced within this pipe. This means that the vacuum has to increase –thus worsening the situation.

It is wise to think of the inlet pipe work -to a pump-as a funnel i.e large pipe work feeding the smaller inlet port.

So if the port is 25 mm then use 38 inlet pipe work –reducing with a tapered fitting at the 25 mm port.

For certain this will reduce or possibly eliminate cavitation.

A reduce pipe on the outlet will typically not harm the pump. However a smaller pipe will mean that the pump is working at a higher outlet pressure than would be the case with a larger outlet pipe. The net result of that is simply higher energy consumption i.e. higher power bills.

The pipe work on the picture is a joke.

A cheap job with a long term high cost.

I agree whole heartedly Bad choice of pipe size, Most Thai and for that mater loads of other so call ed plumbers and engineers do not have a clue about pipe sizes and flow velocities it is so easy these days with online calculators, and manufactures info, and certainly no idea on how to connect pumps for the relevant flows reqd. It is exactly the same principle that the sparks use when sizing cables, or you can't put a gallon in a quart pot.The cause of most pump failures and damage is incorrect pipe sizing .

Edited September 22, 2015 by sappersrest

[sappersrest]

I agree whole heartedly Bad choice of pipe size, Most Thai and for that mater loads of other so call ed plumbers and engineers do not have a clue about pipe sizes and flow velocities it is so easy these days with online calculators, and manufactures info, and certainly no idea on how to connect pumps for the relevant flows reqd. It is exactly the same principle that the sparks use when sizing cables, or you can't put a gallon in a quart pot.The cause of most pump failures and damage is incorrect pipe sizing .

Sorry delight must have got my "connection "mixed up

[sappersrest]

Judging from the last pic, it doesn't seem like the pipes line up as they should. Maybe when they installed them they heated up the pipes to make them bend, in order to reach the pump? That would explain why they eventually collapsed.

Sophon

they heated them up and left the pipes as they are. no such thing like a PVC-pipe collapsing, it's nothing but Thai engineering at its best

disclaimer: i admired the work of the contractor who did my pool piping and his bending by heating up pipes.

Pvc pipe can and does collapse I have seen 10 inch class d melted before on delivery pipe adjacent to a pump, also suction pipe usually happens when a pump operates against a close valve.

[carlyai]

Fluids will only move from A to B if A is high pressure zone and B a low pressure zone.

If the feed into a pump (A ) is at atmospheric pressure –then (B ) must be at a lower pressure i.e a vacuum.

Water under a vacuum condition will tend to partially vaporize

The water is ‘stretched’ producing minuscule sized bubbles.

When these bubbles are exposed to the pressure at the outlet port of the pump –they will implode. This condition is known as cavitation. This typically damages both the pump and the inlet pipe (unless the pipe is metallic).

Also the smaller (and longer) the inlet pipe work –the more friction is experienced within this pipe. This means that the vacuum has to increase –thus worsening the situation.

It is wise to think of the inlet pipe work -to a pump-as a funnel i.e large pipe work feeding the smaller inlet port.

So if the port is 25 mm then use 38 inlet pipe work –reducing with a tapered fitting at the 25 mm port.

For certain this will reduce or possibly eliminate cavitation.

A reduce pipe on the outlet will typically not harm the pump. However a smaller pipe will mean that the pump is working at a higher outlet pressure than would be the case with a larger outlet pipe. The net result of that is simply higher energy consumption i.e. higher power bills.

The pipe work on the picture is a joke.

A cheap job with a long term high cost.

Respectfully, you are completely wrong there in the last paragraph.

This is a typical installation of an Isaan farmer.

I am not taking anything away from an isaan farmer, but the installation is 'the way it's done'.

You find any bits that are lying around to make the job work, and that's it.

A bit of history on this installation.

My Thai niece, on returning here to Isaan on holidays from Australia, decided to buy a "LuckStar" jet pump to replace the one on her bore.

I was back in Aus at the time and my wife in our house next to my neices, decided to buy a 'LuckyStary' pump as well.

So when I got back from Aus the brother-in-law (the great, traditional, hardworking farmer) had installed the pump as you see in the pics.

I looked at the manual and read up on jet pumps but didn't know how they worked, so I decided that our jet pump could stay in its box.

Our bore pump failed, so under pressure from the 'one who must be obeyed' I read up on jet pumps again, looked at the brother-in-laws installation and decided that it just couldn't work.

I set up the jet pump as per the instruction with double pipe, installed it, and it didn't work.

I didn't know then that you have to prime the shit out of it to make it work.

Under more pressure from 'she who must be obeyed', 'look at the neices pump, it's working, no worries, install it like that'.

So still not really understanding venturi pumps I installed it as per the brother-in-laws, and it didn't work.

'So how come the Isaan farmers works, and you Farang with all your knowledge can't get it to work?'

I then posted for help on the forum, under 'jet pumps can't possible work', and got some great replies and was refered to an article that explained to me how venturi pumps worked, and then I understood it! I also found out that you had to prime the shit out of jet pumps.

So now armed with knowing how the pump worked, buying all new higher grade pipe and fittings, I set up the dual pipe jet pump, but when it didn't work, persisted in priming and then, yahoooo, it worked.

My installation is as per the instructions, with all new higher grade pipe and fittings, and knowing how venturi pumps work.

My brother-in-laws jet pump installation is with any bits you can find, and definitely not knowing how venturi pumps work.

Also in the article it mentiones 'tapered fittings', have you seen tapered fittings available here in Thailand, in the country?

Tapered fittings here are the white plastic tape.

[Naam]

Judging from the last pic, it doesn't seem like the pipes line up as they should. Maybe when they installed them they heated up the pipes to make them bend, in order to reach the pump? That would explain why they eventually collapsed.

Sophon

they heated them up and left the pipes as they are. no such thing like a PVC-pipe collapsing, it's nothing but Thai engineering at its best

disclaimer: i admired the work of the contractor who did my pool piping and his bending by heating up pipes.

Pvc pipe can and does collapse I have seen 10 inch class d melted before on delivery pipe adjacent to a pump, also suction pipe usually happens when a pump operates against a close valve.

with "real" pumps = yes. with the shown toys = no.

[lopburi3]

In case you have never seen reduction (tapered) fittings here is one for 27 baht from HomePro. They do have them here. (and actually looking at your photo you seem to have one on pump).

http://www.directtoshop.com/webapp/wcs/stores/servlet/SearchDisplay?searchTerm=pcv+reducer&categoryId=&storeId=10001&catalogId=10051&langId=-1&pageSize=40&beginIndex=0&sType=SimpleSearch&resultCatEntryType=2&showResultsPage=true&searchSource=Q&pageView=

[carlyai]

In case you have never seen reduction (tapered) fittings here is one for 27 baht from HomePro. They do have them here. (and actually looking at your photo you seem to have one on pump).

http://www.directtoshop.com/webapp/wcs/stores/servlet/SearchDisplay?searchTerm=pcv+reducer&categoryId=&storeId=10001&catalogId=10051&langId=-1&pageSize=40&beginIndex=0&sType=SimpleSearch&resultCatEntryType=2&showResultsPage=true&searchSource=Q&pageView=

Yes you are correct.

Sorry, I was thinking of tapered threads

It's not my pump.

My pump is installed more better.

I still put the black rubber bands on everything I do, to make it look more authentic.

This is a pic of my more betterer installation, just temporary at moment as need to move it.

Notice the strategically placed black rubber straps for authenticity.

Also the decrative brickwork under the pump, evidently the LuckStar rusts out so you need to keep it of the ground to let air circulate and hence the expensive decrative brick work.

[lopburi3]

Actually the name is Lucky Star (have several of there sump pumps). And everything rusts unless good SS so always a good idea to keep off the ground (reason your washing machines and such normally include a plastic base unit). And most areas are subject to some flooding during heavy rains.

http://www.luckystar.co.th/