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Quick question!

HypeBuce

Member
Joined
14 Jan 2019
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74
Location
Nottinghamshire
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Unfamiliar with how to read the gauges and determine how much co2 is left. Can anybody help out?


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All full one sits somewhere between 850 and 1000, when mine starts to drop I know I have about 5 days before I need to change. That all depends on diffusion method and bubble rate though.
 
All full one sits somewhere between 850 and 1000, when mine starts to drop I know I have about 5 days before I need to change. That all depends on diffusion method and bubble rate though.

So how empty do you reckon mine is?


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A guess would say between 25% and 50%. How long did it take to drop to that level?
 
Yep, I would agree with that 25-50% or in my case would be 5-8 days before being ceasing to function. I find at 300psi it drops very quickly, usually in a couple of days, obviously dependant on bubble rate etc.
 
The cylinder pressure doesn't go down gradually with use.

It sits at full. Normally 900 to 1000 psi. The pressure starts to drop only when the cylinder is close to empty - then it fulls off a cliff very fast - as said normally over a couple of days.

Your cylinder is reading around 400 psi, therefore almost empty.
 
The cylinder pressure doesn't go down gradually with use.

It sits at full. Normally 900 to 1000 psi. The pressure starts to drop only when the cylinder is close to empty - then it fulls off a cliff very fast - as said normally over a couple of days.

Your cylinder is reading around 400 psi, therefore almost empty.
Yep it's steady until all liquid co2 is gone .
How long it lasts after this depends on the tank volume and delivery rate .
Many change out when it starts to drop.

At this point and with single stage regulators you now risk an End of tank dump.

"the math"..

A regulator’s supply pressure effect is typically provided by the manufacturer. SPE is usually depicted as a ratio or percentage describing the change in outlet pressure per change in inlet pressure. For example, if a regulator is described as having a 1:100 or 1% SPE, for every 100 psi drop in inlet pressure, the outlet pressure will increase by 1 psi. The degree of outlet pressure variation for a regulator can be estimated with the following formula:


∆P (outlet) = ∆P (inlet) x SPE

SPE of course varies by regulator. Also some single stage regs are not prone to this but rare.
https://www.swagelok.com/en/blog/managing-supply-pressure-effect-in-regulator


At an inlet pressure of 1160 psig (80 bar), the outlet pressure is 43.5 psig (3 bar). But when inlet pressure is decreased to 870 psig (60 bar), the outlet pressure jumps to 53.7 psig (3.7 bar). Since the inlet pressure acts on the entire surface of an unbalanced poppet, any change in inlet pressure produces a large change in force, driving a bigger shift in the balance of forces within the regulator.


A common method for reducing supply pressure effect, especially within higher-flow applications where poppets are generally larger, is to use a regulator with a balanced poppet design. The intention of this regulator design is to minimize the area on which the high inlet pressure can act. This is accomplished by allowing the lower outlet pressure to reach a portion of the underside of the poppet through an orifice that runs vertically along the poppet and sealed by an o-ring around the lower stem of the poppet. In terms of supply pressure effect, any change in inlet pressure will result in a smaller change in force because the pressure is acting on a much smaller area.
 
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