Managing gas usage

General
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I’ve done some poking around today wrt managing gas usage, and I think I’ve come up with a reasonable idea?

You can buy ‘mass flow controllers’ which are are a mass gas flow sensor + valve. They get super expensive if you blink but new ones can be had for ‘reasonable’ prices. This one is 0-10L/m, good operating range, valve leak rate is exceptionally low (Helium leaks at 5mL a year), provides both flow output and flow control input on a 5vdc analog. So you could throw a gas bottle in a cage, plumb this onto it, open the bottle valve and leave it open and let the MFC do the work.

You can also find them secondhand commonly: https://www.ebay.com/b/20-SCCM-Maximum-Flow-Rate-Mass-Flow-Controllers/184061/bn_87945361?rt=nc&_sop=15 but it can be hard to find the datasheet or manual for them.

I think this is kind of a one-stop-shop to solve gas metering and control. with a basic micro to control the MFC you can both meter and control output. Considering what we spend on gas this would let us manage and recoup excessive use.

Thoughts?

1 Like
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Let’s do it. Let’s do it now.

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My brain got back into this this evening since the conversation has come up again, so just dropping some links for later reference:

Any mass flow meter would need to support 10SLM, or 10LPM, or 10,000SCCM. (ie 0-10L per min).

Getting one calibrated for argon makes most sense, but not sure how far off the numbers would be if you got one calibrated for something else.

Aera transformer models can be found on ebay for around $250USD ish. theres an analog and digital devicenet version, devicenet is plc canbus magic. theres on online example of someone talking this protocol with arduino.

You can find a bunch of UNIT brand ones, such as UNIT UNC-1100. These have an analog card edge, but they are all from the 80’s, who knows how good they are. Can be found under $100.

DigitalNet version

Analog version

Aera_transformer.ind

Open Control Systems and DeviceNet Applications

Since mass flow controllers are about double the cost of mass flow meters, perhaps a better idea is a separate valve:

SMC VEF3120-3-03 vef base mt 3/8, VEF PROPORTIONAL VALVE
https://www.smcpneumatics.com/VEF3120-3-03.html

14_9_VBA_VE.qxd
https://www.smcpneumatics.com/pdfs/VEP.pdf

welding gas has a high and low pressure side, it may be useful to track these because they may be more indicative of a slow leak than the mass flow meter, as the mass flow meter tends to have a floor where it loses accuracy.

1/8" NPT 5V Stainless Steel Pressure Transducer Sender Sensor Fuel Air Gas AU | eBay

2000 PSI Honeywell Pressure Sensor

IFM EFECTOR Pressure sensor 4 Digit Analog Out – 0…250Bar Range – PN2021 | eBay

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found some more interesting items. This flow meter might just be the ticket.

MF5706 (0 10L/25L) Gas Mass Flow Meter MF5712 (0 200L) Compressed Air Nitrogen Oxygen Argon Carbon Dioxide Digital Flowmeter|Flow Meters| - AliExpress: MF5706 (0 10L/25L) Gas Mass Flow Meter MF5712 (0 200L) Compressed Air Nitrogen Oxygen Argon Carbon Dioxide Digital Flowmeter|Flow Meters| - AliExpress

SMC ITV1051-21N2BS4 regulator, electro-pneumatic, IT/ITV0000/1000 E/P REGULATOR: https://www.smcpneumatics.com/ITV1051-21N2BS4.html

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I’ve been doing more research on this recently and want to proceed with purchasing some sensors to start integrating. The two options I’m looking at are the MF5706 like you posted, or a CFS5008 which I’ve been talking to an Alibaba seller about.

I think I prefer the CFS5008 as it is IP40 rated and doesn’t have the screen and buttons which grinding dust will surely make its way into. We can also get it customised to a flow rate of 35lpm which is just over the max flow rate of the argon regulators so it won’t be possible for people to exceed it’s rating. The cost of either is very similar, both being about $550+GST. We’d need to hook it up to an ESP to get it talking on the network.

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I kinda figured we would have everything in a box and the screen and buttons were totally superfluous lol.

Thats a third of the mass flow controller from omega.

EG00024587.pdf (30.2 KB)

The slight advantage to getting a mfc over mfm is that we can control the flow for the user. but it blows out the cost, and most of our control requirement is more binary (auto full off)

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Yeah, 2 meters for 1/3 the cost of one MFC. I think all we need is the meter + we could add a solenoid in for on/off control. The manual flow valves already fitted are fine for flow control. A good quality solenoid valve runs about $40.

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Yeah so long as the solenoid is high quality that would be good. if its rated for vacuum i assume its fine, i know the mfc’s i was looking at give a rate of expected leakage figure that was stupid low (like 5ml of helium a year or something)