Properly Set Safety Valve

3 32 Reeves Cross

Courtesy of Fred M. Freschette, R. D. 4, Red Deer, Alberta, CANADA.

Fred M. Freschette

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R. R. 4, Red Deer, Alberta, CANADA.

I wrote an article in your magazine about boiling a boiler dry with a 'properly set safety valve' without the boiler exploding. It has been brought to my attention by a good friend that my statement regarding properly set safety valve could be misunderstood and I agree, so I will try to clear this matter up.

I could have said, leave the safety valve off. However, whether you have one on or off, I hope no one will ruin a good boiler to find out. To write about boiling boilers dry just makes good reading and brings up a little controversy, but nothing is really gained unless someone relates their experiences so that others can read and maybe absorb some good from them.

Here are a few boiler experiences I have had:

1. Case boiler from 110 H. P. Installed in Welshe's Western wear in Red Deer. Boiler used for heating. Relief valve set at 20 lbs. Controls failed to operate. Boiler was boiled completely dry and fire continued in firebox until the outer shell was dull red, so firebox would be much hotter. No explosion with relief valve at 20 lbs. Repair all flues loose and stay bolts neededends turned down. Flues rerolled, otherwise boiler put back in service and still okay.

2. Butt Strap Rumely 20 H. P. boiler in Schodopoles shop at Eckville. Relief valve 20 lbs.

Controls failed and boiler boiled dry plus it was oil fired and this extremely hot fire continued until it was discovered in the morningouter firebox shell was red from the heat.

Repairs: all flues rerolled and all stay bolts ends turned down plus some seams recaulked; this boiler was so hot that the engine mount rivets were also leaking. After repairs boiler was put in service and is still going strong.

3. Red Deer Water plant. 2 pass horizontal boiler that controls failed on relief valve set at 20 lbs.this boiler was so hot that the doors to the boiler room had to be left open for some time before the fire could be turned off. Repair: roll and reroll flues, welded construction so no stay bolts loose-boiler still in operation.

I could go on and on but we are dealing with 20 lb. boiler pressure so if there was a proper setting I would say 20 lbs. is about it as the above seems to bear this out.

Let's try the higher pressure:

4. Traction Engine 65 H. P. Case 1915 Butt Strap boiler used for heating water in town of Manning, Alta.

Relief valve set 150 lbs. Inlet and outlet water shut off, apparently. Boiler boiled down quite a ways below crown sheet before the crown sheet let go. It dropped off 8 stay bolts and it sure did clean the grates and blew the firebox door off. I was asked by the old fellow if I would repair it for him. I was up north on holidays and I told him I would repair it for free as most individuals cannot afford to hire a boiler-maker. I rolled the flues twice and caulked the inner firebox seams, and beveled the stay bolt ends and also the crown sheet holes then I heated and carefully jacked the crown sheet up into place, then I welded the stay bolts into place and if I do say so, it was a nice job. I left this engine with 100 lbs. cold water test and it could, with some work on the stay bolts be brought up to test but I quit because the help I was to get never arrived and after 2 days of crawling in and out of the firebox I said to heck with it as it seemed I was the only one interested in fixing it.

The oil industry claimed many of our traction engine boilers for use on drilling rigs. I believe some of the engineers who run them had a grudge against these boilers by the way they abused them.

I have built this miniature boiler for a 3' 32 Reeves Cross Compound that John Kvill of New Norway, Alberta, CANADA, is building.

I have seen boiler under steam, pumped full of drilling mud because the mud pit overflowed into the water pit that the boiler was drawing water from. Can you imagine a boiler filled with drilling mud while under steam? The water legs were all bagged and the mud turns into cement, so these boilers all made a one-way trip to the scrap dealers. Also have seen crown sheets dropped from 35 lbs. up. This was done by injecting or pumping water on dry crown sheets of course no safety valve can handle the explosion of water into steam at this time.

Also have seen flues so badly limed up that all the flues were froze together in one big ball of lime inside the boiler.

Hand hole plate left leaking until it grooved and channeled so bad that the area had to be built up and ground down, flues in front sheet left leaking until the flue sheet was channeled and had to be repaired.

Have seen the cab blown off a locomotive with no one hurt and also seen a collision between two locomotives where the engineer and fireman were both scalded to death.

I would say Barring Material Defects, that 99% of the boiler explosions in Canada and the U. S. A. were and are caused by Human Error, about 95% from someone injecting water on a dry crown sheet, and the other 4% caused by someone setting up the pressure on an old worn-out boiler.

I do hope this clears up the safety valve setting and also throws a little light on the subject. I also wish there were others who would write of their experiences, as I think boiler repairs and boiler failures should be kept in this magazine all the timeconstant reminder to all as to what can happen through carelessness and stupidity.