Cutting Concrete

[chiangrai]

Yep,

I appreciate everybody's advice and you could be right but we have so

many power cuts up here I really want to stay away from a pupm

if at all possible.

[wayned]

Then the only way that you will get the pressure that you want is to put the tank on a tall tower, 20 meters or so!

[sometimewoodworker]

Here are some quotes from a previous post I had...

"As others say, up sizing your pipes is a good idea. Less pipe friction means you'll get more flow and also can run more than one tap in parallel"

"f you can keep all the pipe in large bore pipe all the way to the water heater you will have better pressure."

"Any length of small bore will reduce the pressure, the longer the run the lower the pressure. Also all sharp 90 degree bends reduce the pressure".

So weather up sizing the pipe increases the pressure or the flow it will still improve the likely hood of the

shower having enough water to run the shower...............right?.

I am bringing the 1" pipe all the way to the shower.

I am currently building and doing the same. Also every 90degree change is 45+45 wherever possible. Where they thought I wouldn't look, or forgot, they had to cut out the 90s

[sometimewoodworker]

Then the only way that you will get the pressure that you want is to put the tank on a tall tower, 20 meters or so!

Not really.

There are shower heads designed for low pressure that can give 14 litres per minute with 0.1 bar pressure

Yes 20 metres will give about 30psi or 2 bar, but that hight is luxury not essential.

[sometimewoodworker]

The tank is only about 20ft above the shower and 30 meters away.

At the moment there is 1 half inch pipe coming out of it,doing the hole house and

the shower has nearly enough power to run the shower.If you hold the shower head at waist height it runs fine,if you hold it above your head the gas cuts out.I'm assuming that this is a safety feature that cuts out when the flow of water is so low that the machine will overheat.

The point is that it only needs a tiny bit more water going through it and I am doing 3 things to improve it.

!-Giving the shower it's own pipe from the tank

2--doubling the size of that pipe.

3--making sure that the new pipe has only one right angled bend in it as the present one has many.

I reckon that should do it.If not,there is nothing else I can do save install a pump or raise the tower.

The problem you have is a flow switch not a pressure switch so if you do all you say except for the 1 90degree and make it 2 45s if you can then it's probably problem over.

A report with before and after pictures would be nice

[canuckamuck]

Wot? you want a picture of him in the shower?

[KC 71]

I wish i could find one of my old girlfriends to help you.

She could cut concrete with her teeth !

[Daffy D]

If it is just a matter of getting more pressure to the shower why not get a hot water shower with built in pump?

Years ago when I was in rental room that had pathetic cold shower I got a power shower. I just bolted it onto the wall ran the a cable and plugged it into to the nearest socket outside the shower room and an earth wire through the air bricks to a grounding rod outside.

As I said this was many years ago and don't know if power sowers are readily available but should be no problem from E-Bay or the like.

Worked a treat and took it with me when I left.

[cooked]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

[canuckamuck]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

[cooked]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

Let me put it this way: firefighters know that there is a maximum length of pipe, depending on the coefficient of internal friction, after which not a drop of water will emerge. I really can't remember the exact details, but every bend in the pipe, the dimensions of the pipe (diameter and length) has as a result an effect on the pressure. Not that it matters much in this case but I just feel like being pedantic today.

[canuckamuck]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

Let me put it this way: firefighters know that there is a maximum length of pipe, depending on the coefficient of internal friction, after which not a drop of water will emerge. I really can't remember the exact details, but every bend in the pipe, the dimensions of the pipe (diameter and length) has as a result an effect on the pressure. Not that it matters much in this case but I just feel like being pedantic today.

But you are considering a pump system not a gravity system. As long as that fireman's hose is on down slope. water will always reach the other end (unless it seeps out the sides) no matter how long the hose is. and if capped that hose will eventually pressurize relative to the drop in elevation.

I have a 2" pipe that brings water to my house from 600 meters away. It has 4 - 90 degree corners and I get 5000 litres per hour from it. with no pump.

Not that any of this helps the OP.

[sometimewoodworker]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

Friction is one of the right words as is turbulence, though drag and friction are virtually synonymous, there can also be cavitation as a factor.

Anyway if there is no flow the pressure will be the same however many bends and fittings there are and whatever the pipe size. However once there is flow the length of the pipe, diameter and number of fittings will become important as the more there are the lower the pressure at a given flow rate, and as you can easily imagine the higher the flow the greater the drop in pressure with too many bends junctions etc.

[cooked]

What increases is the friction, the pressure stays the same. So no matter what you do you will get the same pressure, but the flow will be reduced (friction increased) by: Bends and angles, narrow pipes, distance.

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

Friction is one of the right words as is turbulence, though drag and friction are virtually synonymous, there can also be cavitation as a factor.

Anyway if there is no flow the pressure will be the same however many bends and fittings there are and whatever the pipe size. However once there is flow the length of the pipe, diameter and number of fittings will become important as the more there are the lower the pressure at a given flow rate, and as you can easily imagine the higher the flow the greater the drop in pressure with too many bends junctions etc.

A complete misunderstanding of fluid mechanics and the concept of pressure as well as misuse of miscellaneous terminology, Potential turbulence can be calculated and the word drag is not a scientific one. A fireman's hose, after about a kilometre, will not transmit water anywhere. That means that you have zero pressure at the end of the pipe. 'Once there is flow' ... what if you have so much internal friction that there is no flow? Come on, leave it alone.

[Daffy D]

Seem to be flogging a dead horse here

Reading through some of this post again the main points for the OP seem to be low water pressure and unreliable electricity supply.

Think the point has been made that no matter how many or what size pipes are used the shower pressure will not get any better.

The OP says he has a concrete ring tank on raised ground some way away giving a water head of about 20ft. This is enough to trigger the GAS shower heater (which he already has) when the shower head is at waist level but not when it's raised above his head.

Seems to me the difference between a persons waist and head is about a meter so if he had an extra meter or two of water head his problem would be solved.

I'm not a water engineer but why not just add a extra ring or two to give more height to the concrete water tank to give the extra pressure.

[canuckamuck]

I have to disagree. In the OP's case he is getting insufficient flow the shower to start the heater. Adding a meter of lift may fail to make enough difference in his original set-up. Getting a concrete ring 20 feet up a tower is no fun I am sure. Although it might be on a hillside.

Imagine, if you will, that the OP has two sets of pipes going to the shower.

Set 1 is a half inch diameter which goes through many tees and 90 degree turns on the way to the shower.

Set 2 is a 6 inch pipe down to the ground and then back up to shower without any 90's. At the shower each pipe has a 1/2 inch valve pointed at the ceiling. Remember the shower itself is 20 feet below the tank. What will be the result of opening either valve?

Many of you here are insisting that there will be no difference. I believe that the difference between the two sets will be distinct. It is hard to know how much set 1 is restricted because we did not define the length and the amount of turns. But the friction on set 1 would be substantial, and on set 2 it would be almost non existent. Reduce friction and gain flow.

I believe he would get an arcing stream on set 1 and set 2 would hit the ceiling with some force

The OP only needs to increase his flow a fraction. I believe that is easily done but reducing friction. After all, he has 6 meters of head to work with.

Edited April 3, 2016 by canuckamuck

[Daffy D]

"Getting a concrete ring 20 feet up a tower is no fun I am sure"

You got to think outside the box - Slip it in underneath.

[chiangrai]

I've got the pipe installed in the tank and the concrete is drying around it.

Will let you know tomorrow when I connect it all up.

[sometimewoodworker]

... which goes to prove that all I learnt in Fluid Mechanics classes was a load of rubbish.

I admit I am a hack, but I can't be that far off. The water in a convoluted set of pipes will eventually reach the same elevation as a more easily flowing system, it just takes longer to get there. I am sure friction was the wrong word though, how about turbulence and drag?

Friction is one of the right words as is turbulence, though drag and friction are virtually synonymous, there can also be cavitation as a factor.

Anyway if there is no flow the pressure will be the same however many bends and fittings there are and whatever the pipe size. However once there is flow the length of the pipe, diameter and number of fittings will become important as the more there are the lower the pressure at a given flow rate, and as you can easily imagine the higher the flow the greater the drop in pressure with too many bends junctions etc.

A complete misunderstanding of fluid mechanics and the concept of pressure as well as misuse of miscellaneous terminology, Potential turbulence can be calculated and the word drag is not a scientific one. A fireman's hose, after about a kilometre, will not transmit water anywhere. That means that you have zero pressure at the end of the pipe. 'Once there is flow' ... what if you have so much internal friction that there is no flow? Come on, leave it alone.

You must have a strange house if you need a kilometre long fireman's hose

However even at that length if it is sealed it will eventually fill with water. Of course it will be unusable due to no flow because of the friction loss giving no pressure when unsealed. But that was one of my my points.

Though why you seem fixated on a kind of pipe that is only ever used in shorter lengths that is good because it will lie flat when empty, is not very smooth inside so has a much higher friction than PVC or PPR and is totally useless in domestic plumbing, I find difficult to understand.

Anyway we should have the results of the friction reduction tomorrow.

[cooked]

It was stated here that bends in a pipe and pipe diameter don't affect flow. I was just trying to state, in terms that a child should be able to understand, that this isn't true. A fireman's hose has a high coefficient of internal friction and it is a fact that there is zero flow after a certain length of pipe. Firemen know this. This is why they use the pipes only in short lengths as you say and have fire hydrants all over the place. Now get on with your posts about cutting concrete.

http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm

[chiangrai]

So I've hooked everything up and turned on the valve to let the water fill the tank again.

And nothing....there's a drought and there is no water in the mains water.

It might be a few days until the tank is full again.

Another thing that didn't go exactly to plan was buying the pipes.

I went to town and bought 1" hose pipe to get me from the tank to the yard.

Then went to the local hardware shop the buy 1" PVC pipes to go in the channel

that I made in the concrete yard.

When I tried to connect the 1" hose to the I" PVC pipe I couldn't.

The 1" hose measured 1" inch across on the inside and the 1" PVC pipe measured 1 !/4" on

the inside..

So I had to go with 3/4" pipe which measures 7/8" on the inside.

There is now 3/4" PVC pipe set in concrete into the tank.

This is joined to 1" hose pipe that goes down to the yard and is

connected to 3/4" PVC pipe which goes down to 1/2 inch before it goes into the

shower heater.

The joys of DIY in Thailand.The system is now a mixture of 7/8" and 1" pipe which

might still be o.k.

Any one know why the PVC pipes are larger than the size written on the out side of the pipe.

[Daffy D]

"Any one know why the PVC pipes are larger than the size written on the out side of the pipe" - TIT

When you say "hosepipe" do you mean something like green garden hose or the clear flexible stuff?

If the clear hose better cover it with something to stop the sunlight creating algae inside the pipe.

Bad luck about the water drought but hopefully you'll get some water soon and do keep us updated on the results

Edited April 4, 2016 by Daffy D

[surat04]

When I tried to connect the 1" hose to the I" PVC pipe I couldn't.

There are connectors available for connecting flexible hose to pvc pipe.

[sometimewoodworker]

Any one know why the PVC pipes are larger than the size written on the out side of the pipe.

It could be that the sizes are for 13.5 bar pipe which has a much thicker wall than the standard 5 bar that the local shops keep. All the different pressure ratings use the same outside diameter so all the glue fittings work on them.

I'm not currently at home so can't check for you.

Although you are using a flexible pipe instead of the smoother rigid pipe, you should find that you have increased the flow (and reduced the pressure drop while the water is flowing) sufficiently and will soon have showers any time.

BTW you mention that you are using a gas water heater, can you give some information about it?

Was it expensive to buy, is it expensive to run, can it heat water enough when the incoming supply is really cold (cold season water)?

We are currently building and have times of several hours when the power is cut so would be interested in maybe getting at least 1 if it's a sensible choice.

Edited April 9, 2016 by sometimewoodworker

[sometimewoodworker]

It was stated here that bends in a pipe and pipe diameter don't affect flow. I was just trying to state, in terms that a child should be able to understand, that this isn't true. A fireman's hose has a high coefficient of internal friction and it is a fact that there is zero flow after a certain length of pipe. Firemen know this. This is why they use the pipes only in short lengths as you say and have fire hydrants all over the place. Now get on with your posts about cutting concrete.

http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm

You seem to have misread the postings. Nobody said that "bends in a pipe and pipe diameter don't affect flow" we have said all along that they do and that bigger pipe, or shorter pipe and fewer fittings gives better flow. What was said was that they don't affect the pressure. Which is true when there is no flow.

However as you say and as I have said friction will reduce pressure as flow increases, down to zero in your extreme example.

[cooked]

Flow is a function of pressure. There is always a small percentage of fluid mechanics students that can't grasp this concept.

[chiangrai]

O.K........it worked.....just about.

The mains water came back and filled the tank and I was

able to raise the shower head from waist height to head height.

The amount of water coming out of the shower head still isn't great but

it's o.k for now.

So that all proves that your theory was right.There was no major change even though

I changed pipe size.I took out every last 90 degree bend and I think that was what made the difference.

The heater is about 10 years old and made in china.It is strong enough to heat water all year round

and uses very little gas.I will get a new one soon which may work better on low pressure.

Gas water heaters are more powerful and cheaper to run and cheaper to buy.

The only drawback is that they need more water pressure.Thais would use them all the time if they have enough

pressure.They have a safety feature where the spark wont spark to light the gas if the pressure isn't high enough.

There are two sizes.I have the small size which needs the least pressure.

I will eventually get a pump,a bigger size heater and an extra large shower head but for now

I'll make do with what I have.

[canuckamuck]

Congratulations. I was worried when you went with smaller pipe, and flex hose, but you got what you were looking for and you didn't have to pay much.

[Daffy D]

Yes congratulations.

Was a bit surprised when you used several connections and different pipe sizes. I thought the plan was to get smooth turbulent free water flow.

I thought you might have push fitted the 'hosepipe' sections onto the blue pipes to give a smooth water flow.

I used a section of flexible pipe that fitted nicely over the blue pipe and lets the water flow freely without turbulence.

Here I used a section of flexible pipe to allow for vibrations or movement between pump and water tank and not strain the fixed blue pipe that goes up to the tank.

Anyway the main point is you have enough pressure and can now wash you hair

[chiangrai]

I've noticed that I don't have a filter.

What kind of filter could I put in withut loosing pressure.

I don't want to go put it inside the tank because that is the most difficult to clean.