Ok so i have a problem i would like see solved
Example
Collection pot is 1000 liters
Solvent tanks are 150 liters
So say i have 500 liters in collection pot and start recovering into a solvent tank
How can i make sure my solvent tank does not get over filled the 80% mark
A pressure selenoid valve won t work because that will start only once tank is completely filled
The hvac scales don t cut it with the weight involved
what would one have to use for the
Recovery to stop in time
Any scales one can recomend that trigger an alarm once preset weight is
Reached ? At least
@Soxhlet @cyclopath @downtheterphole
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I have a scale with a serial port, so you can get the weight to a microcontroller or computer. But mine is very small, for less than one pound.
What weight requirements do you have?
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If you had a good instrumentation technician. You could run a master/slave plc to shut off from the collection vessel. Look into a float switch. A capacitance might be to hard to obtain.
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The solvent tank is 80 kg
At 80% 120 L x0.6kg= 72kg butane
So 152 kg shutoff when reached
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He a float switch might be a good one
If i could have that in side of the solvent tank and make sure that at all times there are suficcient solvent tanks hooked up then each will fill and shut untill the last one takes the last solvent
That might be a good start thanks
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I’d probably go float switch route. This multi point float switch is neat.
https://www.apgsensors.com/float-switches/intrinsically-safe-multi-point-liquid-level-switch
I wonder if something like this would work for a high end solution. Sure to be crazy expensive.
Overview
Cardinal’s FS series tank and hopper scales are designed for use in wineries, breweries, soap, oil, paint, glass, chemical, and mineral plants, or wherever liquid or material portioning is a necessity. Supplied in a wide range of sizes and shapes to fit almost any tank or hopper; these scales incorporate a link suspension bearing system that absorbs impacts, providing a free-floating platform. The levers are made of structural steel shapes and extra heavy seamless steel tubing to give greater strength than much heavier materials of comparative low tensile strength. Many capacities and variations are available to choose from. May be used with vertical tanks with flat bottoms, horizontal tanks with end discharge, and vertical tanks with cone bottoms. NTEP legal-for-trade.
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Nice Thx 
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We had one from uline that would hold a ton and was accurate to the lb, for crude trim
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I’ve considered rolling my own with pressure transducers. Not just for the recovery tank, but for incoming solvent and to capture the loading in the tubes (or fuge). Trusting anyone to right down anything seems like a great way to lose track of data
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You sure you can’t shave 2kg off that?!?
At that price hacking the alarm to fire a shut-off valve might make some sense
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Found this not many details of pressure ratings etc but made for butane and Propane tanks might be a solution if the heigt. Can be controled
Now it s figuring out wich treads fit to what i HATE treads standerize the world darnit
And i like it s simpicity seems rugged
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http://www.forsentek.com/prodetail_342.html
These are not the right range, but seem really simple to implement.
…yeah, an actual float switch designed for the task? Seems like the right place to start.
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Daisy chain all your recovery tanks together
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Yes i have the solvent tanks daisy chained but there is always one that fills faster than the rest i think this will prevent that from happening
The stop fill valve shuts every tank once filled and the recovered vapor will go to the next i think that by inclining a little the manifold to wich they are all conected i can get gravity to help the sequence 
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If they are all connected, then over filling seems like less of an issue. So long as nobody shuts the interconnects.
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Treu but the problem is I store these vessels in a walk inn freezer and if it s overfilled it s a hassle to get it back at 80%
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We use a float. I can get you model number and pics on Tuesday when back. Hook it up to your pump. Pretty bulletproof
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Do you have the option to switch to larger solvent tanks?
Or better yet a single tank that holds the entire volume of solvent in the system at 80% full? That way this problem (and the potential bad outcomes) are eliminated from your life forever.
With a system as large as yours I would want to eliminate all opportunities for problems, and having to switch solvent tanks 3-4 times during recovery sounds exactly like potential problems. Even though it’s just flipping a few valves, it leaves a huge opportunity for human error.
The only issue with float switches is when something goes wrong, goes wrong, goes wrong.
Once the float switch is installed, it’s difficult to test whether it works properly without removing it again to actuate the float. If there is no way to see visually into the tanks to verify the liquid level I personally would always be worried that a float switch was bad and I would end up monitoring the tanks just as much as before I put the switches in.
If you go this route I would highly suggest you use two switches per tank for redundancy and safety.
It would suck to have a tank accidentally over filled and start leaking, especially if you keep them in an enclosed space (freezer) that also contains other pressurized tanks of flammable solvent.
Even using scales could be an issue IMO. Load cells go bad and read incorrectly, batteries die, people forget to tare the scale out correctly, etc.
For working with large volumes of flammable solvent like you are doing I think you should have the system volumetrically tuned so the possibility of overfilling the recovery tank is eliminated.
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I can not agree more
I have implied several safety measurements and the full stop valve is one
As the 4 solvent tanks get connected to receive from the recovery unit
Their 80% volume is more than the amount present in the collection pot
But one tank fills faster than the other
And as long as all valves are open there is enough space in the system to not have abiatic pressure
But it s cumbersome to take the 20% overfill back out of a tank there for this
Solution seems fit
The recovery unit shuts down once 16 bar is exceeded
All solvent tanks can be visually inspected for volume and have prv on their own
My whole system has a seperate tank with an internal 150 psi prv that takes any overload of pressure to avoid having gasses go airborne
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