BPS drop when cylinder pressure drops

[vinz]

Hi guys,

Just want to check if you exprience drop in BPS when your cylinder pressure starts to drop? My current CO2 setup does this, but I don't recall my previous setups (years ago) behaving this way until the cylinder pressure is significantly lower.

Wondering whether its the quality or some other technical aspect of the 2 different regulators, or my poor memory.

Also, I'm blasting my BPS quite high as its serving a 6ft tank, so naturally when my cylinder pressure starts to drop, it drops really fast. BPS is uncountable.

Current setup is using a Ocean Free Solenoid Regulator. The product details implies it is a dual stage. My previous setup was a Tiren (IIRC) bought from NA years ago. Was probably a dual stage. What also bugs me is that the OF regulator is one of the cheapest in the market, hence questioning its quality.

Thanks.

[AQMS]

Yes Vinz it do drop when the cylinder pressure is low.You are running it on a 6 footer that why
it drop so fast. How big is your cylinder?

[IrvineChen]

Some of the regulator available in the market is Single Stage Regulator.. which mean the output pressure will changes according to the input pressure. So when your input pressure decrease, the pressure might have raise from the output side. You will not encounter this issue if the regulator is 2 stage regulator. Where it regulate twice before going to the output.. so the pressure is more constant

[Shadow]

For single stage regulator, I notice bps drop when the main pressure around 500psi. For dual stage, I did not notice any change even when the main pressure only 100psi. Normally I do top up once main pressure reach 300psi but one time I forgot and notice 100psi and bps still ok.

[AQMS]

Yes for single stage you need to readjusting the dial once the pressure drop.
I have an extra 12lt co2 cylinder if your are interested to have a big cylinder.

[vinz]

Yes Vinz it do drop when the cylinder pressure is low.You are running it on a 6 footer that why
it drop so fast. How big is your cylinder?

For single stage regulator, I notice bps drop when the main pressure around 500psi. For dual stage, I did not notice any change even when the main pressure only 100psi. Normally I do top up once main pressure reach 300psi but one time I forgot and notice 100psi and bps still ok.

5 litre cylinder. Lasts me about 1.5 months. Cylinder pressure drop from 1000psi takes a few days, but I already start to see bps dropping (from uncountable to barely countable ).

This may mean that the OF one is not a proper dual stage regulator. I just checked the wordings on the box last night to see if it mentions "dual stage" but the closest thing is "Built-in depressurize valve to achieve constant and precise CO2 injection". I should have followed my old instinct to never buy Ocean Free.

What brand/models are you guys using for your regulator? Any recommendations?

I'm very tempted to get the Intense one, but have to check whether its dual stage. It is fixed working pressure though. Does that imply it is dual stage?

[Shadow]

Most, if not all the regulator sold at Singapore LFS is single stage. For dual stage you need to get from overseas, UK maybe because same mounting standard. Mine is very-very-very old up-aqua brand. I got it from colleague, he found it when we do packing to move to new office building.

You should follow your old instinct :lo: OF quality is questionable

fixed working pressure is mean you cannot change the working pressure. Most of dual stage, if not mistaken, able to change the working pressure. There is some kind of screw that you can turn to change the working pressure.

[vinz]

Doing some research and came across this document: https://www.mathesongas.com/pdfs/lit...Regulators.pdf

Here's an extract about dual stage regulators (bold by me):

Dual Stage Regulators reduce the source pressure down to the desired delivery pressure in two steps. Each stage consists of a spring,diaphragm, and control valve. The first stage reduces the inlet pressure to about three times the maximum working pressure. The final pressure reduction occurs in the second stage.The advantage of a dual stage regulator is its ability to deliver a constant pressure, even with a decrease in inlet pressure. For example, as a cylinder of gas is depleted, the cylinder pressure drops. Under these conditions, single stage regulators exhibit ‘decaying inlet characteristic’; the delivery pressure increases as a result of the decrease in inlet pressure. In a dual stage regulator, the second stage compensates for this increase, providing a constant delivery pressure regardless of inlet pressure. The dual stage regulator is recommended for applications such as gas supply to analytical instruments, where constant delivery pressure is critical.

Found an article here: http://forum.practicalfishkeeping.co...ad.php?t=80482

It mentions "Working pressure Single Stage Regulator"

Cost a bit more but are far safer, these are what most people in the hobby use. The regulator uses a diaphragm so that the CO2 pressure leaving the regulator will not exceed the level set. The pressure in the bottle may be around 50psi, the working pressure will be 1-3psi, on most regulators the working pressure is adjustable but some have a fixed working pressure. Whilst they are all of a similar design there are many to choose from, welding regulators are big and chunky whereas the aquarium specific ones are better suited to fitting in a cupboard. Most of these regulators come with 1 or 2 gauges to show bottle pressure and working pressure. Some people have reported a problem known as a ‘CO2 Dump’ with these regulators, causing a large amount of CO2 to be released just as the bottle becomes empty as the regulator fails to control the gas released when the pressure in the bottle drops.

So "working pressure" fixed or otherwise does not imply dual stage!

Finally found the Intense CO2 Regulator parked under the single-stage category at co2art.co.uk. I guessed as much from the compact design, but wanted to confirm. Pity... its a really sweet design and comes with BPS fine tuning.

[vinz]

Just based on browsing online LFS, looks like no one sells dual stage CO2 regulators in SG...

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[IrvineChen]

Haha.. LFS didn't sell.. but if you look for industrial CO2 regulator, you will be able to get it..

[Shadow]

you can always buy online
http://www.co2art.co.uk/collections/...age-regulators

[vinz]

Thanks Irvine.

Shadow, I'm considering that, but checking local sources first. But this will probably be similar price or cheaper including shipping... Its about SGD 150+ including shipping from their Amazon store.

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[Shadow]

Thanks Irvine.

Shadow, I'm considering that, but checking local sources first. But this will probably be similar price or cheaper including shipping... Its about SGD 150+ including shipping from their Amazon store.

Sent from my Nexus 5 using Tapatalk

Is it considered Amazon free shipping? JBJ single stage also the same price. Not that I recommend JBJ since the new version quality is extremely bad, based on people post.

[vinz]

Its not free shipping... But I did a checkout to see the shipping to SG... Less then $10! They are having sale at the moment. About 70+GBP. On their Amazon shop is even cheaper at 60+GBP.

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[Shadow]

buy buy buy

[vinz]

Bulk buy? But can only bulk buy 2 sets... else exceed $400 will attract GST.

[tawauboy]

are you using a needle valve?
needle valve should mitigate this issue by controlling co2 flow

[vinz]

Thomas! Long time no see!

Yep, I'm using a needle valve. Not much mitigation. I have to inject at such a high rate that the pressure drops from full to empty in less than a week. I pretty much have to adjust the valve every day or other day when that happens. When I get a new cylinder in, I have adjust again... quite tedious to get the right BPS since its a constant stream and not countable. My next task is to find a way to make the BPS countable.

I'm surprised there's no other way to measure the CO2 output rate... there must be a device out there.

Anyway, I took the plunge and ordered the CO2Art Dual Stage Regulator with precision valve. With the standard shipping its still about the same price as the higher priced single stages we have here.

Yes for single stage you need to readjusting the dial once the pressure drop.
I have an extra 12lt co2 cylinder if your are interested to have a big cylinder.

zerofighterx101, thanks for the offer, but going to decline... I just bought a spare 5 litre so that I don't have to run out to top up immediately.

[Shadow]

What I did for big tank is to split the output using those brash spliter with independent needle valve. That way, I can count easily but then you need 2 or 3 additional bubble counter and diffuser depending on how many you split. The good thing you have better CO2 distribution.

5L finish in a weeks is very fast, are you sure no leakage?

[vinz]

Robert, I'm thinking along the same lines. But I'm using a custom made CO2 reactor, so all the pipes from the separate bubble counters have to come join back into 1.

My idea: regulator -> single needle valve -> splitter (usually comes with needle valve) -> multiple bubble counters -> joints -> CO2 reactor.

I'll fully open all the needle valves for the splitter, then control input via the single needle valve. As they all have the same source and join back to go to one destination, the pressure within the split bubble counters should be the same.

The 5L lasts me about 7 weeks in total. I mean it takes 1 week for the pressure to drop to zero once it starts dropping.