Forced Draft Grates

[WF MASON]

A friend of my was thinking of installing a blower on his 4'x12' Leader dropflue. We were speaking of the forced draft grates compaired to the cast iron grates that come in his evaporator. I was at D+G a short time ago and looked at an arch that had forced draft, the grates were made of steel a with the nickle size holes plazma cut out. I assumed the steel grates would have to be packed with refractory cement ?? The air exiting them couldn't keep them cool enough to stop them from from burning out? I've seen several arches with forced draft grates, but I didn't take particular notice if the grates were cast or made of steel.For some reason seeing them in the catalogs I always thought they were castiron. If D+G make their own steel grates I assume the other 'BIG GUYS' must do the same.
Any thoughts?

[saphead]

I've looked @ Leader forced draft grates several times and they sure look like cast to me. Using steel grates seems like inviting disaster to me. If steel grates are fastened down when they start to move the built up stresses have to go somewhere and that means something will get deformed. I know of a sugarer who bought an air tight arch and he was never told to keep the wood back as far as the grates,the air nozzles around the doors burned off in a season! If you want use air to make a blast ,you should probably go with cast! ... sorry I couldn't help it.

[WESTVIRGINIAMAPLER]

In my experience with any types of steel in an arch for grates for an extended period of time, I have never had any success. I know one commercial producer that uses railroad ties and has to replace them every year or two because they even bow and sag badly.

[Brian]

The 4x14 had a blower on it with grates made of cast but 2 grates were hooked together with cast plate with holes in it, I wounder if steel would work, because a cutting tourch is made out of light metarel and the gas pressure keeps the tip from getting to hot, but would the air from the blower be enough to keep the steel from melting or warping?hmmmm :?:
probabaly the air from the blower would not have enough volume to keep the steel cool enough, I don't know.

HMMMMM I have no practical experiance with blowers yet BUT,,,when I have seen them in action I was always struck by the fact that there was little to no coals built up in the firing chamber or below the grates,,,I have always been told (with a non blown evap.) that you have to keep the ash-coals from building up below the grates as this will cause the grates to warp,,SO it would almost seem like you might be able to get away with it??? what temp does steel melt at and what kind of temps can you get inside the arch and how much of a factor is the cold air going thru the grate?? Parker

[WESTVIRGINIAMAPLER]

Parker,

I don't think it is the coals building up on the underside that would make steel sag and warp, but the heat and most of all the weight on the top side. :D

[Maple Hill Sugarhouse]

Coal's under your grates will warp them thats for sure. I have had 1-2 let go in the past and had coals build up under the other grates and the first ones to heave up are the ones closest to the gap(I used to have something like 9 grates and replaced a couple and now am down to 6 left? go figure.I'm going to get some forced draft grates this year-Lots of cool air coming into the arch would surely help keep the grates cooler for less warpage. Cast is know to warp less then steal...Kevin