Caustic Kills Disconnects?

[Online Brewing Supplies]

No that little pin in the middle that depresses the poppet in the keg looks like it's plastic. My local HB Shop wont stock them, he only stocks the ones with a S/S pin in the centre, as the plastic ones do snap off. I just wondered if the rest of the disco was not up to scratch too.

Its a case of you get what you pay for.We will not stock these either.I only sell the genuine Cornelius DC's with the stainless pins.A different grade of contstruction.For a few dollars more I think they are worth it.
GB

 

[Tony M]

Some plastics are affected by NaOH and sometimes a weak concentration can be more aggressive than a strong. Unless it is known what the material is, only trial and error can be employed. One would expect that a manufacturer would design his product for all conceivable applications but in this case, maybe he did not think past the usual post mix concoctions.
I would not be surprised if the NaOH was the culprit. It would not necessarily "dissolve" the plastic as a solvent could, but could break down some of the cross linking of the polymers, resulting in weakness. My experience has been mainly with polyesters in the mining industry and you should see what caustic can do to that!!

 

[Andyd]

Some plastics are affected by NaOH and sometimes a weak concentration can be more aggressive than a strong. Unless it is known what the material is, only trial and error can be employed. One would expect that a manufacturer would design his product for all conceivable applications but in this case, maybe he did not think past the usual post mix concoctions.
I would not be surprised if the NaOH was the culprit. It would not necessarily "dissolve" the plastic as a solvent could, but could break down some of the cross linking of the polymers, resulting in weakness. My experience has been mainly with polyesters in the mining industry and you should see what caustic can do to that!!

FAir call... Sounds like an experiment is called for

 

[floppinab]

FAir call... Sounds like an experiment is called for

No experiment needed, the proof is in the pics.

 

[oldbugman]

It looks like a structrual problem from the pics, but to shatter like that under low pressure has me baffled.

I lent out my party keg with unregulated gas being supplied from a soda stream machine.

The guys managed to blow the liquid disconnect apart, I wasnt present. I promptly retired that setup.

 

[Online Brewing Supplies]

Just another quick thought.When caustic is added in the presence of CO2 this will cause and implosion due to chemical reactions.So basically it comes back to the structual design and knowledge.I know that this has happened with large costly fermenters (now scrap) which have not been flushed of CO2 before caustic kleening.This may not be the case here but I think a valid point to raise.Caustic + CO2+ sealed vessel = Damage.Hope this helps.
Cheers GB

 

[kook]

Thats not a bad point there. Caustic + carbonic acid... If the reaction is fierce enough to destroy stainless conicals, it would make easy work of a plastic disconnect...

 

[newguy]

Just another quick thought.When caustic is added in the presence of CO2 this will cause and implosion due to chemical reactions.So basically it comes back to the structual design and knowledge.I know that this has happened with large costly fermenters (now scrap) which have not been flushed of CO2 before caustic kleening.This may not be the case here but I think a valid point to raise.Caustic + CO2+ sealed vessel = Damage.Hope this helps.

Are you sure? The local micro that I'm always mentioning managed to 'implode' one of their bright beer tanks during a caustic wash and it didn't have anything to do with a chemical reaction. Caustic is almost always mixed with very hot water because the added heat of the water helps to increase the activity/effectiveness of the caustic. So if you put a small amount of boiling hot water into a sealed, cold, vessel and then start to pump the hot caustic around, thus cooling it, you'll create a very powerful vacuum as the hot caustic cools. This is how they managed to crumple their tank. Now they're a lot more careful about making sure the tank's door can't close during the caustic wash.

 

[matti]

The best utilisation of caustic solution is 0.8-1.2 %V/V @ 85 degrees.
Rinse with boiled water.
(As MHB said. 1-1.5 W/V)

Food factories rinseicycle for close lines are around 20 minutes with 5-10 min rinse.

With cold water it is ueseless and wont rinse off as well.
Some plastics soften up hence the snap in strong caustic solution.

I kept some conc. caustic in clear plastic jar and it wenr milky white after a while and the lid started to crack from opening and tightening it.
it took a couple of weeks though.

cheers

 

[wessmith]

Are you sure? The local micro that I'm always mentioning managed to 'implode' one of their bright beer tanks during a caustic wash and it didn't have anything to do with a chemical reaction. Caustic is almost always mixed with very hot water because the added heat of the water helps to increase the activity/effectiveness of the caustic. So if you put a small amount of boiling hot water into a sealed, cold, vessel and then start to pump the hot caustic around, thus cooling it, you'll create a very powerful vacuum as the hot caustic cools. This is how they managed to crumple their tank. Now they're a lot more careful about making sure the tank's door can't close during the caustic wash.

Caustic soda reacts immediatly with CO2 and that reaction causes a reduction in gas volume, nuetralising the caustic and forming sodium carbonate. It is the collapse of the gas content that creates a "vacuum" and this is what collapses tanks. Just pumping hot caustic or in fact, hot anything around in an unvented tank will cause a vacuum to occur as the liquid cools. This is why ANY tank must have a vacuum break valve as well as a pressure relief valve.

It is madness to operate a tank without both safety valves in place.

Wes

 

[blackbock]

Given that people here say the genuine Cornelius are the only ones to get, how can we tell just at a glance if they are Cornelius? Is there a brand mark somewhere on them, or do we just have to trust the retailer's word? :unsure:

 

[Peter Wadey]

Hi Floppinab,
I use liquid Keg & Line Cleaner from ESB.
Active Ingredient: 300g/ litre Sodium Hydroxide
Dilute 50ml to 5 litres for a keg wash.
Costs about $10 for a litre, so 50c per keg & line clean.
Instruction is to soak for 20min & then flush.
I have connects like yours.
Note: No dissolving required.

Peter