Selection: overpressure relief valve

[neelfirst]

On patient inhale side, after O2 mixing, before humidification.

TBD: before or after inhale pressure/flow measurement?

[esc-works]

Yesterday we purchased a valve from McMaster Carr https://www.mcmaster.com/4277t52-4277T522

[neelfirst]

Did we receive this valve and/or test it? Quick slack search doesn't turn anything up.

[esc-works]

Yes, sorry! forgot to update. I think this is good as long as we have a fan solution (max flow rate is very low but will reliably prevent high pressures as long as its not like 100 cm H2O). Believe we can close this.

[neelfirst]

Confirmed part https://www.mcmaster.com/4277t52-4277T522, closing

[esc-works]

This issue is re-opened. Testing the mcmaster part revealed the first one was leaking at about 20-25 cm of pressure. It also had a very small orifice that would have not allowed for real relief anyway. This is annoying but we'll need a better solution.

[dtgerson]

We also have to figure out what pressure we want this to relieve at

[dtgerson]

see this chain for some valves we decided to try out: https://respiraworks.slack.com/archives/C0137BLF17A/p1590501836181400

[Rafee-UM]

From INDIA side we have ordered an over pressure relief valve as per the attached data sheet. Once we got that from the vendor we test it and will update the results. 002-019-1003 is the model which we ordered. SAFETY RELIEF VALVE CATALOGUE.pdf

[Rafee-UM]

As discussed here https://respiraworks.slack.com/archives/C0137BLF17A/p1590440382159500, INDIA team is planning to develop a safety relief valve with help of Umbrella type check valves, which will have absolutely zero leak until the crack pressure is arraived. These are made of medical oxygen compatible elastomer material. we are getting the sample quantity of Umbrella valves, once we recieved them, we will revert back with test results. please find the attached umbrella type check valve as your reference. UM 070.006 SD.PDF; UM070.006-151.01.pdf

[inceptionev]

Note 2x of Generant VRV-750B-V-0.8-X have been ordered for the US build. Additionally, two equivalent GRVS units have been ordered for evaluation. Expected Oct 11th.

Next steps:

• Complete the US enclosed ventilator build
• Compare notes with India build
• Do a complete design review

[inceptionev]

This comment copied over from duplicate ticket #611 (now closed): India team has been working on this and selected this valve 002-019-1003: https://respiraworks.slack.com/archives/C0111E2GFPF/p1596284702108100

[martukas]

Turn out that what we have ordered is actually VRV-250B-V-0.8, which can be decoded using this: https://www.generant.com/wp-content/uploads/2019/09/SA.SL_.VRV001.G.4514-Series-VRV-Product-Literature.pdf

[martukas]

The valves have arrived. I think this can be closed for now unless testing reveals the need for an alternative.

[martukas]

In discussion with @tijanim a problem has been identified that might possibly be a fire hazard. The overpressure valve comes after oxygen mixing and releases the gas into the enclosed ventilator assembly, where electronics reside in the open. In case of 100% oxygen, there may be fire hazards. If this is true, we need to select an "inline" version of the valve, so that we can direct the output to be dumped outside of the ventilator unit.

@jmriphagen @inceptionev @mrkensan thoughts on this?

[inceptionev]

Good catch! Would it make sense to route the patient outlet such that that the relief valve can be placed outside the unit? Is there a easily sourceable inline version of this valve?

On Thu, Jan 14, 2021 at 7:36 PM Martin Shetty notifications@github.com wrote:

In discussion with @tijanim https://github.com/tijanim a problem has been identified that might possibly be a fire hazard. The overpressure valve comes after oxygen mixing and releases the gas into the enclosed ventilator assembly, where electronics reside in the open. In case of 100% oxygen, there may be fire hazards. If this is true, we need to select an "inline" version of the valve, so that we can direct the output to be dumped outside of the ventilator unit.

@jmriphagen https://github.com/jmriphagen @inceptionev https://github.com/inceptionev @mrkensan https://github.com/mrkensan thoughts on this?

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/RespiraWorks/Ventilator/issues/656#issuecomment-760623592, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACCCNNPAYLZZXTVYXF6EPQDSZ6Z2ZANCNFSM4OIHYFFA .

[inceptionev]

Ok, looks like the inline version is just VRVIxxx (with the same parameters)

On Thu, Jan 14, 2021 at 8:00 PM Edwin Chiu inceptionev@gmail.com wrote:

Good catch! Would it make sense to route the patient outlet such that that the relief valve can be placed outside the unit? Is there a easily sourceable inline version of this valve?

On Thu, Jan 14, 2021 at 7:36 PM Martin Shetty notifications@github.com wrote:

In discussion with @tijanim https://github.com/tijanim a problem has been identified that might possibly be a fire hazard. The overpressure valve comes after oxygen mixing and releases the gas into the enclosed ventilator assembly, where electronics reside in the open. In case of 100% oxygen, there may be fire hazards. If this is true, we need to select an "inline" version of the valve, so that we can direct the output to be dumped outside of the ventilator unit.

@jmriphagen https://github.com/jmriphagen @inceptionev https://github.com/inceptionev @mrkensan https://github.com/mrkensan thoughts on this?

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/RespiraWorks/Ventilator/issues/656#issuecomment-760623592, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACCCNNPAYLZZXTVYXF6EPQDSZ6Z2ZANCNFSM4OIHYFFA .

[martukas]

Related question -- what pressure should tubing be rated for the relief valve outlet? Related to #996