Piping Layout

if this is compressed gases, you can't overfill.

If you are concerned about something real put a check valve on each container so you cannot flow into it. Put each container on a scale and monitor the weight.

it is compressed liquefied gas

I don't know how cold the liquified gas is, but a check valve does seem the best solution. I'm sure a cryogenic fluid handling vendor could supply one.

Automatic Control : The LPG vessel can be furnished with a nozzles for installing a level controller consists of level switch and level transmitter LT to be connected to a control valve, LCV.

Or, Manual Control : By installing a level glass LG to indicate the level of LPG.

If both the vessels are connected to each other by the lower nozzles at bottom, a one controller may be required, otherwise two controllers are required (one per vessel).

Note. To minimize the number of nozzles on the vessel, you can use a bridle tube (piping fabrication) to be connected to the vessel with only two nozzles, and the bridle itself furnished with a nozzles for both level switch and level glass.

thanks,

actually i Have this huge one ton container there is no nozzles no glass sight meter,

any way my concern is not the container getting empty,

my concern is to ensure the flow will go to the system not to go to the next container and causes overfill,

this two containers are connected individually to the pipe line but they consider in parallel connection,

thanks for your trial

Can you use a float level control and a automatic 3 way valve that would close or open when it switches on/off according to a pre set level on each tank? I am not sure about the liquefied gas but I use this set up on allot of tanks when they are filled by a common header. It is simple and reliable for me.

pipwelder

pneumatic pressure valve ? maybe

I have connected two, three, four, and more LPG tanks in parallel and yes one tank can be filled to more than 80% level. This can happen when one tank is in the sun and another in the shade.

The one tank being filled above the 80% level should be of no concern as the pressure will be the same throughout the system.

The 80% restriction is for one tank or in the case of parallel it would be 80% of the whole system.

If the tank that is over 80% starts heating, its pressure will increase and push the liquid back into the less full tank. Pressure will equalize and the liquid level will self adjust.

Non of the tanks in parallel can have a non-return valve so it will not prevent equalization.

If the entire system (one tank or more) is filled to more than 80% level while cool, and then the system warms the volume of liquid can exceed the capacity of the tanks causing rupture.

look like you have a lot of experiences in that subject,

you might have an idea about that

i was told that, manufacturer standard is to keep the liquid line (pipes that is connect to the one ton container) above the centre line of the container around 12`` to ensure that your one ton container which set horizontally on the scale, (and have a diameter of 30`` , and contain a 3`` of vapor in top of the LCG level....)

then we will have the lowest point in the piping line always in higher level than the liquid line in the container,

they said it is a blind standard means no explanation why,

and I'm trying to figure out why?

wonder if you have any idea

thanks again

I have not seen that standard. And we draw the liquid from the bottom of the tank and run the line at ground level to the vaporizor.

On a large refractory dryout we may use as many as 30,000 gal of propane and we have not had any problems with how we run the lines.

thank you,

this really a great article,

do you have any think like that in case of using compressed liquefied chlorine gas?

We are a designers and fabricators for all sizes of LPG vessels.

The size of 1 ton LPG (1800 litre) is a mass production, and each vessel of that size is equipped and furnished with the following accessories (valves, instruments, and gauges):

1. Pressure regulator ½"x½" REGO Type LV4403, to be installed into multi valve combination.

2. Relief valve 1" REGO Type 8684G.

3. Multi valve ¾" REGO Type 7556VR12.

4. Excess flow valve 3/4" REGO Type 7572FC.

5. Filler valve 1-1/4" REGO Type 7579C.

6. Level gauge 2-5/8" ROCHESTER Type 6281 (float type with dial gauge).

Also, we are a suppliers for LPG and propane, and a lot of these vessels (1800 litre) are filled daily by connecting them in parallel to a main header through multi branches (one branch for each vessel), and the level is monitored by the level float gauge, without suffering from any problem

As always Abdel hits the nail on the head. I learn from his post.

pipewelder

Thank you pipewelder,

You are welcome.

you have to provide one way valve /non return valve at the pipe in between and before each tank total two Nos. To prevent passing water from each container to the next one. the above is according to my understanding your words.

You cannot use a non-return valve if using a vaporizer!

A vaporizer boils the LPG and when it builds up excess pressure it is fed back into the tank, other wise the pressure relieve (pop off valve) will open and you will squirting LPG thirty feet into the air.

As long as the gas does mot exceed the combined total of 80% there is no danger if one tank is fuller than the other.

The hottest tank will push liquid to the other tank but there is no harm in that unless you shut the valve while one tank is the over filled.

As long as the gas does mot exceed the combined total of 80% there is no danger if one tank is fuller than the other.

can you explain more this part please

thank you

If you connect two or more tanks in parallel and don't have a check valve (non return valve) the volume will not overpressure the fuller tank.

This could happen if you had one tank in the shade and the other in the sun. The hotter tank will have the higher vapor pressure and the cooler tank would have liquid from the hotter tank pushed into it. The pressure would be the same in each tank no matter that one had more liquid.

By law the tanks can only be filled to 80% so that as the liquid expands it will not over pressure the tank. If the tank were filled to 100% and there was no withdrawal and the tank shut down then as the liquid expanded the tank would be overpressure and the (hopefully) the pressure release valve would vent. The vented gas would be a fire or explosive danger. If the pressure release valve failed then the tank could rupture.

But if the tanks or system is not over filled (above 80%) there would be no danger as excess pressure would balanced and it would be vapor pressure which will compress.

As long as both tank valves remain open and there is not a non-return valve, the system cannot exceed the design vapor pressure.

I have often had 3 to six tanks connected together and saw the liquid being transfered to the cooler tank/s.

If you are drawing liquid from your tanks you must be using a vaporizer and should not have a non-return valve in the system.