http://wp.me/pNMpN-1H My Latest blog post at Barista UK: Sainsburys espresso machine explosion: Industry impact?
"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......!
Boiler explosions are dangerous for sure, even a small boiler like in an espresso machine. I am glad you were not hurt more than you were. Please do get your hearing checked out, file a claim with the store to get it on record for the future.
Steam packs a huge amount of energy into a small space and to maintain the system safety, takes effort, this is one reason that the railroads don't use steam engines anymore, the cost to take care of them was huge and the potential problems if you didn't are plain to see.
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
as an opinion from a technician (and a seller of equipment as well) YES an espresso machine owner should have the machine maintained and indeed it is his/her responsibility,
HOWEVER the seller of the machine ( or more in a case of a chain) or the roaster if is done in the "Italian way" should be the one that will sell or include with equipment a water softener and a preventive maintenance plan and saying once per years it is a VERY conservative way of doing it but better then no service at all, no excuse for that unfortunately sometimes the lure of a big sale obscures all the other good points
In my opinion, responsibility is entirely with the manufacturer of the equipment. A failure of the boiler, by exploding and potentially causing injury or death should simply NEVER happen.
A runaway heater + a clogged safety relief valve = bomb?
Where is the next fail-safe element in the design? There should be at least one or more safety mechanism(s) to prevent explosive pressure failure of the boiler; plain and simple. A 'blow plug', a seal plate, a weak link somewhere in the system to relief the excess pressure of a runaway boiler.
The operating pressure of the boiler is 2 bar. This is so far lower than explosive pressures, there is no excuse. This is not a high pressure steam engine!
If this is all that is between you and a bomb in your kitchen, I would unplug immediately.
well it might ends in that direction but all components are certified and equipment is normally tested so we will see what the end of this is going to be
a speculation from my end ( I never seen a machine EXPLODE in 10 years of working on them but I've seen a lot of safety valve doing their job) possible scale building up in a way the the safety valve was bypass or not reachable by the excessive pressure or a close expansion valve and the heating exchanger blow or or or we will know more about I hope
I think there is no way that the maker can be held liable for this. The machine was tested and passed all the need tests when it was made. The maker has no control over how the user uses and services the equipment. It was made with a safety valve and only lack of maintaining it properly could result in what happened.
The user has the duty to keep whatever they own in safe operating condition, regardless of what it is. If it can be shown that this espresso machihne was serviced on a regular schedule, then the person who serviced it is the party where the blame can be laid. With the many thousands of these machines in service, boiler mishaps are exceedingly rare and I would wager that the problems that do occur are not a result of a makers defect but of service and maintaining or lack there of.
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
c4h5n2o Senior Member Joined: 19 Jul 2005 Posts: 234 Location: Vancouver Expertise: I live coffee
Espresso: LM Grinder: Bunn/Vario Drip: Swiss gold Roaster: No time
Posted Wed Sep 15, 2010, 1:31pm Subject: Safety valve maintenance for home machines
After this incident, it seems safe to predict a resurgence of how/when should I test/replace my safety valve? threads. To be clear, a business i.e. cafes need to have a qualified technician do an annual inspection/service. Period. Any other approach not only compromises safety but exposes a business to needless liability. But what about our home machines? Most of us do not schedule an annual service call to inspect our home machines. It doesn't seem unreasonable to hold home machines to a different standard since they don't cater to the public. But safety is still important. So what should we be doing at home?
For myself, I'm not fond of things exploding in my house. Even an unplanned safety valve opening could cause a lot of water damage. So my machines have a PID controlling the normal boiler pressure. The original pressurestat is then configured as a secondary cutout at a higher pressure (1.5bar). And the safety valve is the final safeguard that should trip around 1.8 bar. You don't want your boiler to exceed it's design limit, which is typically 2bar. An actual explosion probably means that the safety valve didn't open and the pressure exceeded 20bar. For anyone interested in looking at the standards for commercial/industrial safety valve testing, it's probably ASME PTC 25 or the equivalent.
I don't believe that safety valves fail very often. But pressurestats do fail often enough and I know lots of people with machines that have had the safety valve open. Since the safety valve really is your last line of defence, you shouldn't neglect it to the point where it might seize. I test my safety valves (on my home machines) every 18 - 24 months by first letting the machine cool, removing the safety valve and visually inspecting it for scale or anything unusual. Then reinstall it, bypass the pressurestat/SSR (temporarily & under direct supervision!) and observe that the safety valve opens around 1.8bar. And that it reseats and remains sealed after returning to normal operating pressure. Does anyone do it differently? Any expert opinions about safety valve maintenance for home machines?
I think there is no way that the maker can be held liable for this. The machine was tested and passed all the need tests when it was made. The maker has no control over how the user uses and services the equipment. It was made with a safety valve and only lack of maintaining it properly could result in what happened.
The user has the duty to keep whatever they own in safe operating condition, regardless of what it is. If it can be shown that this espresso machihne was serviced on a regular schedule, then the person who serviced it is the party where the blame can be laid. With the many thousands of these machines in service, boiler mishaps are exceedingly rare and I would wager that the problems that do occur are not a result of a makers defect but of service and maintaining or lack there of.
It's better - and safer - to wait for a proper engineering report and evaluation. However, at the moment, Sainsbury's are blaming a design change in the machines in 2009, and have reinstated all their machines made before that point. Seemingly this machine was made sometime in 2009. I don't know what sort of routine maintenance a machine of its age should have gone though by now.
They're not the sort of company to risk their very high reputation with the public on a wild assertion, although they (or more probably their insurers) surely have the best lawyers money can buy.
Hopefully those injured will have no long term ill effects, but it will have been a helluva shock.
I still stand by my statement. I really doubt that is a mfg defect, I suppose it could be but I doubt it.
EDIT: Being connected with manufacturing as I am, it is impossible to know how a user may use/abuse what you made. You make your item the best you can and comply with all the regs that are in effect. After that, it is a crap shoot ;<))
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
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