BajaNomad

pressure tank

volcano - 3-5-2012 at 07:13 PM

is it possible to use a pressure tank to boost water pressure:mad: in a gravity flow situation without the use of power or pump?

[Edited on 3-6-2012 by volcano]

Sandlefoot - 3-5-2012 at 07:18 PM

Sure! If you let the gravity fill the tank before you pressurize it. Then you have to add more water each time you need it without any pressure in the tank then re-pressurize again...& again...& again...till you get so tired of it that you put in a pump in line and forget it.

Ateo - 3-5-2012 at 07:21 PM

Contact the Department of Industrial Relations Pressure Vessel Unit and ask their opinion..............haha.



:lol::lol:

volcano - 3-5-2012 at 07:29 PM

I'm the gal that just got waterline in to cabana, slight gravity situation, and no power yet nor for a while...............might as well live in a cave

comitan - 3-5-2012 at 07:40 PM

NO !

J.P. - 3-5-2012 at 07:43 PM

Sounds like yuo may need a hand pump, or elevate the tank:wow::wow:

Islandbuilder - 3-5-2012 at 08:32 PM

You can't get more pressure than you have head, without introducing it from an outside source such as a pump.

I don't see any way to get higher pressure without raising the height of the tank or using a pump. Lots of ways to get pressure short of an electric pump. I guess it depends how long before you get your electical system going as to how much energy to put into an alternate.

A small wind powered pump may be worth looking into.

Terry28 - 3-5-2012 at 09:45 PM

If you have a long enough run consider graduated pipe.....bigger to smaller..

Mulegena - 3-5-2012 at 10:21 PM

Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..
This is a great idea, Terry, at least in theory.

Got any specs on that for reference, plz?

KaceyJ - 3-5-2012 at 10:38 PM

Basically No.

The maximum gain you can accomplish with gravity feed is the number of feet of elevation above the faucet /fixture in your home that the water source comes from.

Appx. .43 lb. / ft. elevation pressure

ie , if the highest elevation of the source is 10 feet above your shower head then you will have 4.3 lbs. pressure.

A pressure tank adds air pressure over stored water to boost pressure and requires energy to do so .

volcano - 3-6-2012 at 07:50 AM

.............. thanks for the educated answers..clearly I'm going to need a pump eventually. no neighbors

comitan - 3-6-2012 at 08:05 AM

If you gave 12V consider an RV pump.

larryC - 3-6-2012 at 09:33 AM

Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..


And what do you accomplish by going to a smaller diameter pipe other than reduce your flow?

Islandbuilder - 3-6-2012 at 09:41 AM

Quote:
Originally posted by larryC
Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..


And what do you accomplish by going to a smaller diameter pipe other than reduce your flow?



Yeah, it's one of those things that seem to make sense, like putting your finger over the end of a hose to spray your walkway. Until you do it. You can't make more pressure, just reduce and concentrate the flow.

With very low pressure, ALL you have is volumn, so less pressure equals more water used. A pain when you have to haul it in, and therefore spending a bit to get at least one panel, one battery and a $75 12 volt RV or Marine pressure pump is justified.

greengoes - 3-6-2012 at 09:45 AM

Quote:
Originally posted by larryC
Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..


And what do you accomplish by going to a smaller diameter pipe other than reduce your flow?


Nothing else, it is a misconception that pressure increases as it passes into a smaller pipe.

12 v

volcano - 3-6-2012 at 09:45 AM

Quote:
Originally posted by comitan
If you gave 12V consider an RV pump.


yes. and I actually have other 2v questions.
we may be able to do a slar panel or 2 next year. the cabin is small, and we will only want a few lights, tv satellite dish. thought I would look for an rv set up. 12 v is the way to go for our needs, right? not 110/solar....we are way off grid

Islandbuilder - 3-6-2012 at 09:55 AM

My limited experience would say that yes, with some reservations.

!2V takes heavier wire than does 120V to avoid resistance voltage loss , so if you have long runs, or a lot electrical stuff, the wire cost can get high.

I guess you could always use a small point of use inverter if you ever wanted to add a small microwave?

I suggest a single 12v battery, and a solar trickle charger hooked directly to the battery for running your pressure pump until you get your larger solar system sorted out.

Islandbuilder - 3-6-2012 at 12:23 PM

Quote:
Originally posted by soulpatch
And if dollars/pesos right now are the issue you can hook it right to your vehicle battery.
A small, cheap cigarette lighter solar panel would keep you ahead of the game until you were able to afford a more permanent solution.

It'd be down and dirty but you'd be able to rinse off.


There ya go, best short term advice yet!

David K - 3-6-2012 at 01:34 PM

Quote:
Originally posted by greengoes
Quote:
Originally posted by larryC
Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..


And what do you accomplish by going to a smaller diameter pipe other than reduce your flow?


Nothing else, it is a misconception that pressure increases as it passes into a smaller pipe.



CORRECTAMUNDO! Smaller pipe actually reduces pressure (because there is more friction).

Pressure is created by elevation or a pump. The higher up the water source, the more pressure (force) it will have (.433 lbs. per ft. of elevation). If you can't get the water supply higher, then adding a booster bump/ pressure tank is the cure.

Flow is determined by the pipe size. A bigger pipe can flow more gallons at the same time as a smaller pipe can. Bigger pipe has less friction and less loss of pressure than a smaller pipe moving the same gallons.

Velocity (speed) is increased by reducing pipe size, but pressure (force) is reduced. Water cannot be compressed (as air can), so you can't 'squeeze' the water to create pressure. The water needs to move faster in a smaller pipe to move the same gallons through a big pipe. If the pressure is high, and you open and close a valve at the end of a small pipe, the pipe will shake or a hose will move. Velocity is the enemy... cured by either reducing the flow, reducing the pressure, or increasing the pipe size.

Some people get velocity and pressure mixed up, and think that making water run through a smaller opening helps with pressure... but it only makes the water move faster... this is how sprinklers can 'throw' water up to 30 feet even if the pressure is only 40 pounds per square inch (PSI)... Which is on the low side for most home applications that use more water (per minute) than a sprinkler.

Alan - 3-6-2012 at 07:07 PM

Quote:
Originally posted by Terry28
If you have a long enough run consider graduated pipe.....bigger to smaller..
I think that would simply increase the friction loss. You are stuck with existing head pressure without a pump.

volcano - 3-8-2012 at 08:12 AM

I think the 2500 L pila is probably about 6 or 8 feet higher at the base than the faucets inside the cabin. the run to the cabin is about 75 feet. we just buried pvc of 3/4 ". I think next year, when the tank drains again, (I'm in Oregon again), I will raise the tank by 3 concrete blocks...and see if that improves the pressure enough. My vehicle parks 100 feet away.
If I get an rv pump, and pressure tank ..where would they be set up? on the house end of the run?

Islandbuilder - 3-8-2012 at 08:20 AM

The pump can go anywhere on the water line, wherever it's easy. They make a little noise (more as they get older), so I wouldn't put it under the bed.
They have a built-in check valve that prevents pressure loss back toward the tank. If you don't install a small accumulator tank it will run every time you turn on the tap. A accumulator tank will allow the pump to run only every few quarts, or gallons, depending on the capacity of the tank. The drain on your battery will be the same regardless, the pump will still pump as many gallons as you use. It will run less often, but longer each time.

I will raise a question for others to answer for you:
How about going to a 24v DC system instead of 12v? Pros and cons?

[Edited on 3-8-2012 by Islandbuilder]

Hmmmmmmm

bajaguy - 3-8-2012 at 08:25 AM

Maybe a 12 volt RV/Deep cycle battery, a small solar panel to maintain/charge the battery and a 12 volt RV on demand water pump.

http://www.campingworld.com/index.cfm?affiliateid=1491

gnukid - 3-8-2012 at 09:17 AM

A simple solution is a sunshower bag, make a mini tower with 10x1x2 to haul up the bag in the air using a simple line and block, fill it up, raise it up and take a shower. No power, no cables, no batteries, hot water pressurized shower.

bajaguy - 3-8-2012 at 09:31 AM

Quote:
Originally posted by soulpatch
Friction loss on 3/4 inch is huge.
PVC is cheap so consider putting in 1 inch line and then put the pump and, if you want to spend the dollars, the pressure tank near your electrical source since 12v DC has it's own "friction loss" issues with small wire.
Elevating your tank a few cinder blocks 75 feet away isn't going to produce much more than a sore back.
I got a closeout washdown pump from West Marine for pretty cheap and it is my back up pump.... always good to have a spare when the replacement part is hundreds of miles away.





Hey, thought you would have an American LaFrance triple pumper as a back-up!!!!! :lol:

Alan - 3-8-2012 at 11:11 AM

Quote:
Originally posted by bajaguy
Quote:
Originally posted by soulpatch
Friction loss on 3/4 inch is huge.
PVC is cheap so consider putting in 1 inch line and then put the pump and, if you want to spend the dollars, the pressure tank near your electrical source since 12v DC has it's own "friction loss" issues with small wire.
Elevating your tank a few cinder blocks 75 feet away isn't going to produce much more than a sore back.
I got a closeout washdown pump from West Marine for pretty cheap and it is my back up pump.... always good to have a spare when the replacement part is hundreds of miles away.





Hey, thought you would have an American LaFrance triple pumper as a back-up!!!!! :lol:
Be very careful, I think your age is showing. I haven't heard them referred to as a triple combination in I can't remember how long :lol: Of course the simple fact that I knew what you were talking about exposes my age too.:lol:

Yup, very old!!!

bajaguy - 3-8-2012 at 11:20 AM

Quote:
Quote:
Originally posted by Alan
Hey, thought you would have an American LaFrance triple pumper as a back-up!!!!! :lol:

Be very careful, I think your age is showing. I haven't heard them referred to as a triple combination in I can't remember how long :lol: Of course the simple fact that I knew what you were talking about exposes my age too.:lol:





Yeah, maybe Soulpatch is too young!!!!!!

larryC - 3-8-2012 at 11:44 AM

I can see worrying about friction loss if you were trying to pump 100 gpm through a 1.5" line and trying to maintain 100psi nozzle pressure but 3 or 4 gpm through a 3/4" line isn't going to create enough friction to worry about.
The simplest solution is to raise the tank, maybe put it on the roof of your place, if your structure will support the weight. If that is not possible then a pump of some sort is going to be necessary. Check on ebay, lots of pumps available there. As soulpatch said, parking your vehicle next to the house and useing its battery would be pretty simple.
good luck
Larry
PS The first rig I was on was a Ward LaFrance.

[Edited on 3-8-2012 by larryC]

msteve1014 - 3-8-2012 at 05:32 PM

Lots of people have a small tank on the roof to gain head pressure, and a larger tank on the ground to hold most of the water. You still need a pump to get it up there, but maybe only once a week, or so.

David K - 3-8-2012 at 05:42 PM

Quote:
Originally posted by msteve1014
Lots of people have a small tank on the roof to gain head pressure, and a larger tank on the ground to hold most of the water. You still need a pump to get it up there, but maybe only once a week, or so.


Best idea yet! Just plug in the pump once a week to fill 'er up!

David K - 3-8-2012 at 06:47 PM

Frank, your Way cheap link doesn't do it.

KaceyJ - 3-8-2012 at 10:47 PM

After looking at Diana's orchard pics, it came to mind you might benefit from constructing a standpipe near your hut.


Your shortcomings in pressure might be able to be balanced by an increase in volume.

kc

Alan - 3-8-2012 at 10:58 PM

As a basic rule of thumb you will only gain about 1/2 psi for each foot of elevation. I would think a simple inline pump would be much more cost effective than building a tower.

David K - 3-8-2012 at 11:56 PM

Quote:
Originally posted by Alan
As a basic rule of thumb you will only gain about 1/2 psi for each foot of elevation. I would think a simple inline pump would be much more cost effective than building a tower.


Yes, as mentioned above the figure is 0.433 psi per foot. But she has no power at the site for a pump... just a car battery a hundred feet away (or something like that)... Gravity is free.

volcano - 3-9-2012 at 07:53 AM

been using the sun shower bag for 5 years now...
little by little we work on the cabin..

here is another thought as well.... it seemed that one of the faucets had way worse pressure than the others....it could be the make and model.....?
does any one ever remove screens and aerators for better flow?

o.k. won't bother raising with blocks

and regarding 12v vs...the cabin was wired for 110...in my absence.... but the most advice I'm getting is for 12 v

I'm reading this Thread carefully, guys

Mulegena - 3-9-2012 at 07:58 AM

Can I pick your brains, too, please?

We're building a little house right now-- just finished clearing the land and digging the foundation (yeay!).

Its a small 2-story, and I think we'll put one bathroom on top of the other and it'll be a gravity-flow situation from a rooftop tank. Here's a couple questions:
* which bathroom should the shower be in, top or bottom floor? (the bedroom's on the top floor, so I thought the shower would be on the same, but am concerned the gravity-flow pressure might be inefficient up there).
* the water will be routed through an on-demand hot water heater. where should that be placed to maximize psi?
* how high should the roof pitch be? obviously pitched would be better but we were thinking of doing a flat, pueblo-style roof too. would that make much a difference?
* what else am i not factoring in?

vandenberg - 3-9-2012 at 08:09 AM

Quote:
Originally posted by Mulegena
the water will be routed through an on-demand hot water heater. where should that be placed to maximize psi?


Better make sure there's enough pressure, otherwise that heater won't work right.

Water Heater

bajaguy - 3-9-2012 at 08:28 AM

Quote:
Originally posted by vandenberg
Quote:
Originally posted by Mulegena
the water will be routed through an on-demand hot water heater. where should that be placed to maximize psi?


Better make sure there's enough pressure, otherwise that heater won't work right.





At least a 3/4" water supply line to the heater with 60lbs of pressure (ideal) and at least a 3/4" gas supply line to the heater.

Any less than 40lbs of pressure and you will have problems with the heater

Pump should go as close to the heater as possible.

[Edited on 3-9-2012 by bajaguy]

Alan - 3-9-2012 at 09:19 AM

Quote:
Originally posted by Mulegena
Can I pick your brains, too, please?

We're building a little house right now-- just finished clearing the land and digging the foundation (yeay!).

Its a small 2-story, and I think we'll put one bathroom on top of the other and it'll be a gravity-flow situation from a rooftop tank. Here's a couple questions:
* which bathroom should the shower be in, top or bottom floor? (the bedroom's on the top floor, so I thought the shower would be on the same, but am concerned the gravity-flow pressure might be inefficient up there).
* the water will be routed through an on-demand hot water heater. where should that be placed to maximize psi?
* how high should the roof pitch be? obviously pitched would be better but we were thinking of doing a flat, pueblo-style roof too. would that make much a difference?
* what else am i not factoring in?
You don't say where you are building but by your screen name I will make a wild guess and assume somewhere in BCS. Unless you are on a mountaintop somewhere and need to address snow loads I would think that a flat roof would work fine. Just don't make it perfectly flat and level as all building materials will settle some over time and you don't want a pool of standing water that can't drain off. This applies to patios as well. Slope everything just enough that water will flow AWAY from your house. My patio in La Paz was built perfectly level and on the few times each year that we get significant rain the water runs in under the door which we try to stop with rolled beach towels :no:

mtgoat666 - 3-9-2012 at 09:28 AM

Quote:
Originally posted by David K
Yes, as mentioned above the figure is 0.433 psi per foot. But she has no power at the site for a pump... just a car battery a hundred feet away (or something like that)... Gravity is free.


gravity is not free in this case. energy has to be expended to get water up into elevated tank. if you ignore the effort to lift the water up in first place, then you can say the "gravity is free."
just sayin....

wessongroup - 3-9-2012 at 09:58 AM

There maybe some information in this "article" which may help...

http://www.cee.mtu.edu/sustainable_engineering/resources/tec...

http://www.ironmanwindmill.com/

[Edited on 3-9-2012 by wessongroup]

David K - 3-9-2012 at 10:19 AM

Quote:
Originally posted by mtgoat666
Quote:
Originally posted by David K
Yes, as mentioned above the figure is 0.433 psi per foot. But she has no power at the site for a pump... just a car battery a hundred feet away (or something like that)... Gravity is free.


gravity is not free in this case. energy has to be expended to get water up into elevated tank. if you ignore the effort to lift the water up in first place, then you can say the "gravity is free."
just sayin....


Gravity (down) is free, but going against gravity (up) is costly.