Pressure Tank

[RideJocky]

I want to add a pressure tank to work as an air bladder to reduce my water-pumps cycling.

 

I’m think of using an old LP tank, has a one used one of these as an air tank? Anyone know if the thread in the top is a standard pipe thread?

 

The installation:

A tank on the ground floor is fed by municipal water, as is the bathroom on the ground floor.

 

The pump draws water from the tank on the ground floor and pumps it to the tank on the roof. The roof tank feeds the bathrooms on the 5th, 4th and 3rd floors.

 

I would like to use the pump on the ground floor that fills the roof tank to also pressurize the bathroom on the ground floor and the kitchen on the second floor because the municipal water pressure/volume is too low.

 

The problem is that with a float switch on the roof turning the pump off and on, it won’t come on for the grind floor bathroom. If I can’t make the tank work I’m thinking I’ll install a solenoid valve on the pipe doing to the roof tank and operate it with a float valve.

 

If the tank works it would be ideal.

 

[RideJocky]

The tank:

[sfokevin]

Add these near the faucet...

 

https://www.lazada.co.th/products/ro-12-pressure-tank-i387232631-s752502201.html?spm=a2o4m.searchlist.list.7.7a4b1e75L9nmMS&search=1

[Artisi]

Just now, RideJocky said:

The tank:

I use the larger version gas tank on one house I lived in, welded a "T" pipe fitting (inverted) in the bottom of the tank, 1 side to the pump 1 side to the house supply with a valve on each side with a valve on the top to assist when purging tank of water as you need to isolate it from the system occasionally to drain it so there is an air pocket in the top. 

Worked extremely well and in service for over 10 years before a major update of the overall system. 

 

NOTE: IF WELDING ANY FITTINGS ONTO THE GAS TANK, ENSURE THE TOP VALVE IS OPEN OR REMOVED AND THE TANK IS COMPLETELY PURGED OF GAS - otherwise boom-boom and not the happy type of boom-boom

 

[RideJocky]

I use the larger version gas tank on one house I lived in, welded a "T" pipe fitting (inverted) in the bottom of the tank, 1 side to the pump 1 side to the house supply with a valve on each side with a valve on the top to assist when purging tank of water as you need to isolate it from the system occasionally to drain it so there is an air pocket in the top. 
Worked extremely well and in service for over 10 years before a major update of the overall system. 
 
NOTE: IF WELDING ANY FITTINGS ONTO THE GAS TANK, ENSURE THE TOP VALVE IS OPEN OR REMOVED AND THE TANK IS COMPLETELY PURGED OF GAS - otherwise boom-boom and not the happy type of boom-boom
 

Why did you add a T to the bottom rather than just removing the valve and screwing a T in?

[RideJocky]

Add these near the faucet...
 
https://www.lazada.co.th/products/ro-12-pressure-tank-i387232631-s752502201.html?spm=a2o4m.searchlist.list.7.7a4b1e75L9nmMS&search=1

I looked at these. What is the maximum pressure, and are they safe for compressed air?

[VocalNeal]

What is the maximum pressure delivered by the pump. I'm thinking a piece of large diameter 6in blue pipe mounted vertically would do just as well. 

 

Solenoid in the line to or at the roof. 

 

Tap on in ground floor bathroom pressure goes down pump switches on. Solenoid opens pressure drops, pump starts.

Edited September 25, 2019 by VocalNeal

[RideJocky]

What is the maximum pressure delivered by the pump. I'm thinking a piece of large diameter 6in blue pipe mounted vertically would do just as well. 
 
Solenoid in the line to or at the roof. 
 
Tap on in ground floor bathroom pressure goes down pump switches on. Solenoid opens pressure drops, pump starts.

Yeah, I figured the solenoid valve would work, but I’d rather avoid it I can.

Thought about the 6” pipe as a tank, but by the time I buy the pipe and fittings I’d be into it for a few thousand anyway.

[Artisi]

1 hour ago, RideJocky said:

 

Why did you add a T to the bottom rather than just removing the valve and screwing a T in?

 

because you need air (pressurised by the pump) over water for it to work. 

[RideJocky]

because you need air (pressurised by the pump) over water for it to work. 

I understand that, but why the need fo an opening top and bottom?

What does the opening on the top do?

[Artisi]

38 minutes ago, RideJocky said:

 

I und, erstand that, but why the need fo an opening top and bottom?

What does the opening on the top do?

 

Allows the tank to be drained easily to recharge the air. 

Should have said initially 1 of the valves either pump to tank or tank to house needs to be 3way - to lower the water level and allow air recharge into the top via top valve. 

[RideJocky]

Allows the tank to be drained easily to recharge the air. 
Should have said initially 1 of the valves either pump to tank or tank to house needs to be 3way - to lower the water level and allow air recharge into the top via top valve. 

How often did you have to drain it?

I thought I would just go with:



On the bottom and depend on gravity. If too slow I can run a hose up to bleed it...

[Artisi]

5 minutes ago, RideJocky said:

 

How often did you have to drain it?

I thought I would just go with:



On the bottom and depend on gravity. If too slow I can run a hose up to bleed it...

 

What ever suits you, I found it a very simple task to open the top valve, close the pump to tank and 3 way tank to house valve and drain out some water, took maybe 5 minutes and back online again. 

 

How often - depending on usage, but from memory 4 / 5 weeks, but then I would do it anytime I thought  the pump recycle time was becoming a bit too often and I had 5 minutes to spare. 

[RideJocky]

What ever suits you, I found it a very simple task to open the top valve, close the pump to tank and 3 way tank to house valve and drain out some water, took maybe 5 minutes and back online again. 
 
How often - depending on usage, but from memory 4 / 5 weeks, but then I would do it anytime I thought  the pump recycle time was becoming a bit too often and I had 5 minutes to spare. 

Every 4/5 weeks or 4/5 times a week?

I think if I can get the existing valve out I’ll go that route. I no longer have ready access to any welding equipment.

[Artisi]

12 minutes ago, RideJocky said:

 

Every 4/5 weeks or 4/5 times a week?

I think if I can get the existing valve out I’ll go that route. I no longer have ready access to any welding equipment.

 

4 to 5 weeks. 

[RideJocky]

4 to 5 weeks. 

Thanks, that would be great.

[Artisi]

1 hour ago, RideJocky said:

 

Thanks, that would be great.

 

Remember, it is based on usage - more thru put shorter period. 

[RideJocky]

Remember, it is based on usage - more thru put shorter period. 

I plan to make it pretty easy to drain so even once a week would be okay.

[Artisi]

1 hour ago, RideJocky said:

 

I plan to make it pretty easy to drain so even once a week would be okay.

 

No need to completely drain the tank each time, just sufficient to ensure a reasonable amount of air in the top of the tank   - experience after awhile will kick-in as to how much. 

[RideJocky]

I did something similars, with two pieces 10" blue PVC pipe,parallel to each otherabout 1700mm long. Works very well. Only I am surprised how fast the air inside dissolves in the water. Next time I will place an innertube from a truck inside, and bring that on the pressure from the water in the tank.....
 
Arjen.

Yeah, I hadn’t considered the air dissolving into the water, I was assuming that if I had no leaks I would be okay.

The inner-tube would work, but without a way to refill it, and assuming the air will permeate the tube same way it does in tires it will slowly go flat. Charging the tube with nitrogen is cheap and easy but it only slows the process. Of course given (I think) the pressure inside the tube (gas) and outside the tube (liquid) the this may not happen, I don’t know.

Thinking about it, I could add an air-chuck to the top of the tank, and use a compressor to blow the water out rather than draining it. This will keep the floor dry and minimize the amount of water entering the tank when the pump starts.

Also, by charging the tank with composed air from the top, and making the water pipe from the bottom of the tank longer, it may be possible to keep the air-water interface within the pipe.

I believe limiting the surface area of the water to the cross-sectional area of the pipe should greatly reduce rate air can dissolve into the water.

[RideJocky]

Giving is some thought, I might not need another tank, I might can just use a compressor, which I’m in the market for anyway...

 

 

 

[Artisi]

1 hour ago, RideJocky said:

Giving is some thought, I might not need another tank, I might can just use a compressor, which I’m in the market for anyway...

 

 

 

The compressor to do what, destroy your pipe system? 

[tifino]

when the vision built in the mind gets saturated...

find a diagram - suitably modified;

swapping In pressure bottles, overflow catchment, and pumps! 

  a=

b=

c=

d=

e= etc etc

just like in a similar hypothetical thinking situation where one plans to insert a pumped hotwater recirculation system for constant (temperature) 

 

 

why not consider the type of on-demand pumps used for roof rainwater catchment storage/garden watering hose pressure systems? 

 

[RideJocky]

The compressor to do what, destroy your pipe system? 

Why would I want to destroy the pipe system?

The compressor would be used to purge the tank and maintain a charge.

[RideJocky]

when the vision built in the mind gets saturated...
find a diagram - suitably modified;
swapping In pressure bottles, overflow catchment, and pumps! 
  a=
b=
c=
d=
e= etc etc
just like in a similar hypothetical thinking situation where one plans to insert a pumped hotwater recirculation system for constant (temperature) 
 
 
why not consider the type of on-demand pumps used for roof rainwater catchment storage/garden watering hose pressure systems? 
 

Like to minimize the number of moving parts. I understand a compression won’t do that, but if I have a compressor anyway, it might make sense.

What is your diagram supposed to be showing?

[sometimewoodworker]

5 hours ago, RideJocky said:

The inner-tube would work, but without a way to refill it, and assuming the air will permeate the tube same way it does in tires it will slowly go flat. Charging the tube with nitrogen is cheap and easy but it only slows the process. Of course given (I think) the pressure inside the tube (gas) and outside the tube (liquid) the this may not happen, I don’t know.

Well a couple of points. All Inner tubes come with a refill point all you have to do is put a rubber washer over the thread between the tube and the hole through your PVC end cap.

 

The second point is that filling with nitrogen makes absolutely no difference to the rate of tyres deflating.

 

The only use case for filling tyres or inner tubes with dry nitrogen is in aeroplanes, because they have to withstand under -60C to over +200C other gasses will freeze and water will boil exploding the tyre.

 

Every garage or tyre shop selling the nitrogen fill is completely full of it. While it is of absolutely no benefit it only harms your wallet.

Edited September 28, 2019 by sometimewoodworker

[bankruatsteve]

I fill my tires with 78% nitrogen.  Seems to work OK.

[tifino]

2 hours ago, RideJocky said:

What is your diagram supposed to be showing?

just a hypothetical headache inside the roof, if there was no pre-planning... 

 

 

but (you'll) be fine ⛲ 

[RideJocky]

Well a couple of points. All Inner tubes come with a refill point all you have to do is put a rubber washer over the thread between the tube and the hole through your PVC end cap.
 
The second point is that filling with nitrogen makes absolutely no difference to the rate of tyres deflating.
 
The only use case for filling tyres or inner tubes with dry nitrogen is in aeroplanes, because they have to withstand under -60C to over +200C other gasses will freeze and water will boil exploding the tyre.
 
Every garage or tyre shop selling the nitrogen fill is completely full of it. While it is of absolutely no benefit it only harms your wallet.

Well there is also the issue with getting the inner-tube inside the tank. I assume if you’re using PVC you glue it inside with the cap and hope for the best, but if you did have a leak around your valve stem you’d be hosed. In any event, I’m wanting to use a steel tank, preferably OTC.

While I won’t argue the value of paying a tire shop for a nitrogen fill, you are wrong about nitrogen not permeating slower than air, or at least the oxygen component of air.

Pretty easy to remove water from air, and I’m not sure how a little condensate freezing in a tire would cause it to explode. That said, water vapor does contribute to greater pressure fluctuation.

I don’t know why aircraft, race cars and some trucking companies run nitrogen in their tires, but I always thought it was to minimize the fire hazard associated with blowouts and to minimize pressure fluctuation.

I don’t pay for nitrogen in my tires, but if I bought a new set of tires I would demand a free nitrogen charge with my purchase.

The tire shop I used to trade with always included nitrogen in new tires and flat repairs and they would always top them up free anytime I stopped.

I currently top up about once a month at a local pump, and they all seem to have pretty moist air.

[sometimewoodworker]

6 hours ago, RideJocky said:

 

Well there is also the issue with getting the inner-tube inside the tank. I assume if you’re using PVC you glue it inside with the cap and hope for the best, but if you did have a leak around your valve stem you’d be hosed. In any event, I’m wanting to use a steel tank, preferably OTC.

While I won’t argue the value of paying a tire shop for a nitrogen fill, you are wrong about nitrogen not permeating slower than air, or at least the oxygen component of air.

Pretty easy to remove water from air, and I’m not sure how a little condensate freezing in a tire would cause it to explode. That said, water vapor does contribute to greater pressure fluctuation.

I don’t know why aircraft, race cars and some trucking companies run nitrogen in their tires, but I always thought it was to minimize the fire hazard associated with blowouts and to minimize pressure fluctuation.

I don’t pay for nitrogen in my tires, but if I bought a new set of tires I would demand a free nitrogen charge with my purchase.

The tire shop I used to trade with always included nitrogen in new tires and flat repairs and they would always top them up free anytime I stopped.

I currently top up about once a month at a local pump, and they all seem to have pretty moist air.
 

 

With the inner tube I would screw it to the blanking cap before gluing the cap on. A reasonable level of care will ensure that ther is no leak.

 

the difference in size between a nitrogen molecule and an oxygen one is 300 picometers to 292 picometers or 2.7% however given that only 21% of air is oxygen 1% other stuff and 78% nitrogen that drops the difference down to 0.54%. So yes, if your rubber is gas permeable the nitrogen filled tyre will loose less. But it is so little less that it is virtually impossible to measure.

 

The only tyres that benefit from dry nitrogen are as I said larger (more that about 30 seats) aircraft. They have it because the tyres are pumped to about 200 psi and go from temperatures of under -50 to possibly over 200C. If there were moisture in the tyres it would certainly freeze at cruising altitude and imbalance the wheels then on landing the wheels go from a dead stop to around 190 MPH in a fraction of a second and you can imagine what out of balance wheels would do. Then any water would be flashed into steam taking up 1600 times the volume of the water. Not a good idea.

 

As to why, it's quite simple, all compressed nitrogen is dry so it's extremely simple to guarantee that there is no water or anything else that can freeze. 

 

While you certanly can dry compressed air (diving air is) it's a more complex filtering job.

 

As to why trucks and race cars, if they do, run on nitrogen it isn't because it's any better, it's because they believe it is.

 

You have totally lost me as to why an air fill could be a fire hazard, I can't think of any way it could be.

 

you might enjoy

 

 

Edited September 28, 2019 by sometimewoodworker