> > On another serious note. > > Fusible plugs have the same chances of failing as RCD's and all other > safety > devices. Right now, I am trying to think of one that is completely > failsafe, > and can't. ( If anyone can think of one, then please tell me what it > is!! ) > What can make it hard for fusible plugs to work, is if they get a > thick > enough scale build up over the top of them...... This, while under > test, has > been found to hold back the steam in some circumstances. There is a > very > simple cure for this, and that is to replace the plug at every > testing of > the boiler as the minimum frequency. That seems to nail it for the > hobby > boiler very nicely. For the commercial boiler, they have to be > replaced > according to the relevant standard. Over here (West Aust.) it is > annually at > a minimum frequency. In the marine world, I believe it's at every > inspection, which is (I believe) every 2 years.......? I can't > remember > now..... > Regardless, they are the best safety device known to man so far...... > I > suppose we could invent a infer-red temp scanner that will read the > temp's > of all the firebox plates and set of an alarm if the plates get too > hot..... > And the best bit is that you need to measure the fire side of the > sheets as > they are much hotter than the water side...... So now it must > withstand > 1500°C, and would need to be calibrated annually to ensure that it is > actually working... at the time of calibration...... > Nothing is perfect, so we just have to do the best we can. > > > Have a great weekend. > > > Cheers, > > Phill. > > MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.