3VZ-DPNI AW11 wrote:
I've just read through the link and am still unsure as to the mode of failure.
It would have to be the bottle itself splitting open to cause so much damage.
The angle I'm coming from is if there was no failure with the tank itself and this was just the rupture disk doing its (limited) job then we can take the heating method out of the equation.
Although the force and effect of a rupture disc bursting is quite violent, neither the force from the venting itself nor the potential effect of that force on the bottle, would be adequate to do such damage.
At worst when a rupture disc fails the force should only knock the bottle over. Although we secured the bottle when we carried out our demo of a rupture disc Vs our SPRV, you can still see the effect on the bottle wasn't violent enough to do the kind of damage seen in the recent accident.
If that is the case would exactly the same thing have happened if the bottle was in an electric heater blanket without a pressure cut off switch? Food for thought.
Regardless of if not being a consequence of the rupture disc bursting (which also begs the question as to why it didn't), there is still the potential for such a failure to occur when ANY form of heating is used on a bottle, which is why I REFUSED to offer bottle heaters before we offered our SPRV.
HOWEVER, WON customers using our bottle heaters have NOTHING to fear (or at least MUCH less than MOST American nitrous users), for the following reasons;
1) WON bottles are manufactured in a much better way from a single billet of alloy and as a consequence they are inherently stronger plus they are thicker just for good measure.
2) WON bottles conform to much higher EU safety standards - US safety standards are much lower, which is why it's actually illegal to fill US bottles in the UK
3) Using a blow torch concentrates the heat in a localised area which weakens that area, making the risk of a bottle failure more likely.
4) Unlike most US bottle heater kits (which use cheap and inadequate thermostat control, WON heater systems are either controlled by a pressure switch or when used with a Max, they are monitored by an even more accurate transducer and controlled by the Max itself.
5) In THIRTY FIVE years of using/selling nitrous oxide, I've NEVER known of a single WON customer suffer ANY major safety issue.
Also how many of us have the older WON kit that has a burst disk not a valve?
Even with the old style rupture disc type valves you are at a lesser risk than someone using a US bottle but we STRONGLY ADVISE ANYONE with a rupture disc (including those using US bottles ESPECIALLY) to upgrade to our SPRV.
For the record, the cost of a SPRV is less than half the cost of a bottle fill and it could easily save you not only the cost of the contents but also the cost of replacing the bottle, plus the cost of a race weekend and potentially yours or someone else's LIFE.
