# Espresso machine explosion



## LeeWardle (Nov 16, 2008)

Several hurt in espresso machine explosion

"ruptured pipe".......????? More likely that the pipe ruptured because the over-pressure valve failed. The valves are tested and/or replaced in the yearly service. Time and time and time again I have said to cafe owners that regardless of the cost the MUST HAVE THE MACHINE SERVICED EVERY YEAR! It's because signs of wear are highlighted and safety mechanisms checked. I have lost count of the neglected machines I have serviced where the over-pressure valve was stuck closed. All it takes is the pressure switch to screw up and, well you're screwed! It's lucky nobody was more seriously hurt. Steam at high pressure will strip flesh from bones. Imagine holding your hand on the holes of the steam want and opening the valve (!!!!!!!don't do this!!!!!!) were talking serious deep burns. Now imagine twice that pressure (an over pressure valve pops at 2b, twice the normal boiler pressure) or even more? God it doesn't bare thinking about.

Tell you what, this will shake the industry up a bit......

Lee

Coffee Machine Engineer


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## BanishInstant (Oct 12, 2009)

Gulp. Looks very nasty


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## LeeWardle (Nov 16, 2008)

Latest blog post on the subject: Sainsburys Espresso machine explosion: Industry effect?


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## vintagecigarman (Aug 10, 2009)

Lee: Are there any lessons or implications here for home machine safety?


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## sandykt (Dec 3, 2009)

OMG! Does not good.


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## Glenn (Jun 14, 2008)

A well written. informative and thought provoking blog post Lee.

This should be a wake up call for the industry. It's the same as having a smoke alarm but never checking the batteries&#8230;


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## Glenn (Jun 14, 2008)

Just came across this gem. I wondered how long it would take for the coffee machine jokes to start.


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## LeeWardle (Nov 16, 2008)

Glenn said:


> A well written. informative and thought provoking blog post Lee.
> 
> This should be a wake up call for the industry. It's the same as having a smoke alarm but never checking the batteries&#8230;


Thanks Glenn! This a story I'll be following for a long time. I think it's going to wake up every council, EHO and operator. The rules are there, they are just not (on the whole) followed or policed.



vintagecigarman said:


> Lee: Are there any lessons or implications here for home machine safety?


Good question! Thankfully a domestic boiler is really tiny. You'd be surprised but they don't come much bigger than the average large mug! The safety mechanism is very different though. The over pressure valve releases into the cold water tank. (notice two hoses? one of these is the over pressure).

Gaggiamanualservice is a chap to best answer this but I would say that a regular de scale will be sufficient. If you notice any hissing etc. it will be a failing gasket. Get it looked replaced as where hot meets cold you get loads of scale and will block (usually the group or the steam valve) which makes de-scaling much harder.


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## APScrim (Sep 13, 2010)

If motivated they could design the thing to fail safely for those occasions where all other safeguards fail. For example, a weak point certain to burst first and release the pressure over a several seconds would be dramatic but much less likely to cause injury.

Alan


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## Glenn (Jun 14, 2008)

An update on the issue is here


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## DavidS (Apr 8, 2010)

We had a machine explosion at my cafe a few years back if I remember right... No one hurt (someone was very near by at the time though) Can't remember the exact details though... It was that delonghi that's sitting in your cupboard under the stairs Lee


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## LeeWardle (Nov 16, 2008)

Ha Ha, only branded Delongi, it's a La Spez really. It was only the safety valve that popped wasn't it?! They go off like a shot gun!


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## LeeWardle (Nov 16, 2008)

Glenn said:


> An update on the issue is here


I wonder whether it was the Valve that had the modifacation (I.E. new valve) or they just moved it. I note from the photo that the valve has a brass bowl surrounding it? Bezzera's have these too. Their Safety valves incorporate and anti vac valve too. (that's to say in the same brass housing, not dual function







) The bowl has an O ring that seals it to the valve housing. It catches the run off from the anti vac and then a bit like a Heat-sinc lets the water evaporate quickly. This bowl could quite easily collect Milk/syrup/staff drinks/anything else they might put on the machine top. This would effectively weld the valve closed.

Lee


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## ricke17 (Oct 7, 2010)

Ironically, they serve really nice coffee at this branch of Sainsburys which is about 5 minutes away from where I live!

Rick.


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