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have caught fire I want a little information on the point of safety of the electrical process, i, e, whether there is a certain naxture of air and gas at which there can be an expli stof even with an electrically heated oven

The matter of rate is the one that the prospect generally brings up first and of course you have to try to satisfy him on that Twit It possible, it should be the last thing that is mentioned because intelligent handling of the oven will probably cut more figure in his monthly cost than the rate will I have in mind a case of an electric oven where they obta ned a heat in about 45 muutes and, because of lack of n'ethod in handling, the ir prodi t, the oven stood open for 35 minutes bet veen Feats Now, it they had moved with the sana degree of rapodity that is me other people do, they would have had a second heat almost out of the oven bet re they pit it in, as they work in w 1h time they have to heat up all the metal that is represented by t'e con struction of that oven, and it cots them more to do that than it does to heat the material they enamel and sell

I hope that some of the members here will be able to give us a little information on these various poents.

MR. SCHEROK: May I ask as a matter of information, whether there are any examples of central stations employing dectric heat as a part of their generating and d tribitingg systems? Are these statements to be taken simply as a pre li tron?

I understood one speaker to say that there have been several explosions He probably referred to overs heated by the direct current system, and I think it will be well to bear in mind the progress that has been made in the indire thy heated oven and ren ember that the danger which exits my Divers

by gas does not exist to anything like Pe indirectly heated

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with the electric unit, and when in correct combination with air exploded. Of course with a properly designed electric oven these explosive gases are allowed to escape through the proper vents. In figuring the fire hazard of a gas oven versus an electric oven, you must therefore take into account the design of the electric oven and see that the above feature is cared for.

MR. TRACY: I do not quite understand. Is the question with regard to fires and explosions in directly heated gas ovens as opposed to ovens that are heated by the indirect method? MR. SCHERCK: The explosions from the directly heated gas

oven.

MR. TRACY: I should not have qualified the statement by saying that it was directly heated. The statement is made continually by some of the manufacturers of the newer type of oven, the indirectly heated oven, that it is impossible to cause an explosion because the gas flame does not come in contact with the vapor in the oven, and to that extent the statement is true as there can be no explosion from that cause. They are said to be explosion proof. I saw one in the northern part of the city, and I went to see the second one which had been installed about two weeks. The man who operated it was to tell me something about the operation and how entirely explosion proof it was; but about three hours before I reached there they had taken him to a hospital and he died from the effects of an explosion. It is practically impossible in japanning in a gas heated oven to prevent the conditions that cause explosion. If you heat the metal that lies between the indirectly heated oven and the product to a red or white temperature, you will have the same chance to cause fire or explosion as if you put the flame directly into the oven. Of the ovens that I have mentioned, two of the three were heated by the indirect method of heating. The tubes used in the ovens and the floor of the oven that lies between the material and the flame become almost white hot and the chances of explosion and fire are apparently as great as they are in directly heated ovens. There are, however, many good talking points for the newer type of oven. Probably they are something like the electric oven in that they have not been used long enough for us to say what they really will do.

DR. C. F. HIRSHFELD, Detroit: I think we can settle the question raised by the last speakers. When electrically heated

enameling ovens were first installed, they were in competition with direct fired gas ovens, that is, ovens in which the flames of the gas burners were in the chamber in which the raw work to be japanned was placed Now, there is no question about the fire hazard in a case of that sort. Periodically, or haphazardly, you are bound to have fires With the development of the electric oven came the development of the indirect gas-fired oven, and the electric oven brought another thing and that was speed of production. Production is the god of most factories of the present day, sometimes even at the expense of quality, and when it became evident after the installation of a few electrically heated ovens that it was sometimes possible to cut the tine of japanning to 30 percent or less of what it had been before, production managers proceeded to do it They also tried to do the same thing with the indirect heated gas oven Now, in either case, it comes Most of you probably drive

back to a very simple proposition or have driven automobiles You know you can get an over rich mixture or you can get an over lean mixture, and you cannot ignite either of them The vapors that come off the ja; anning in the oven are practically of the same caracter as the vapor in a gasoline engine, and if you get the right mixture and proper temperature, you will have an explosion The har ler you drive an oven, the higher you tend to drive the temperature in that oven, and if you get the proper mixture and proper ten perature, and luck is against you, you will have either an explosion or a fre, according to whether the d ́ors happen to be open or closed, and whether the outlet flues are big or small

But these are all controllable pints; mixture and tempera ture can be made safe if proper precautions are tåen On the other hand, in the indirect fired gas oven, you have gas ben g burned in an ench sure, and sooner or later the man wi› is oner ating the oven will have a mental lapse and forget to light the pilot light until after he has turned in t'e mam burners an ! his a nice mixture of gas and air in the combustion chambers of the oven If he bts the plot under suchen linens, a bad expla son is likely to be the result

That is the inherent Barandd v u have in the in det fel gas even How serious it will be, tie alone will tell It is a bazard that d ́es not exist in the eles the oven

Here is another thing Ilave 1 more or less

with metal plates subjected to the action of products of combustion from gas burners, and the experience has convinced me that it is only a matter of time until those plates corrode to such an extent that they are punctured, and when the plates or flues of an indirect fired gas oven are punctured, the vapors from the japan are certain to enter the gas flues. It is then only a matter of time or luck; a fire is sure to result ultimately. This holds no matter how well the oven may be constructed and despite safely low operating temperatures under normal conditions. I think that this covers the situation of fire hazard, as nearly as I am able to state it at the present time.

MR. COLLINS (closure): As regards the fire hazard in the electric oven, I think Professor Hirshfeld has stated that very much better than I can myself, and my views are exactly in accord with his. It is a controllable condition, therefore the design should take care of it.

In regard to figuring the necessary heat required for a given operation of an oven, that is something that cannot be expressed in a few words. Elementary figuring must be done in the way of estimating, and perhaps you can get the right result by using a constant, but you would not, I fear, use that constant frequently enough to make it worth while. Those of us who have been figuring upon these propositions have been able to figure fairly closely. Whether that is good luck or good figuring I am not sure, but you will have to have some experience in figuring a given proposition in order to temper the mathematical calculation. That is, in other words, your constants would depend a good deal on the nature of the design of the apparatus; so that I do not feel capable of answering that question here, directly and absolutely.

As to the question of insurance, I have no direct figures on just what will be the result of the use of the electric oven as against fuel-fired ovens, but I am sure it will be one of the points which will argue decidedly in favor of the former.

REPORT OF SUB-COMMITTEE ON ELECTRIC

FURNACES

RH TILLMAN, CHAIRMAN

DISCUSSION

Mi M. O. DiTPUAIN, Syracuse, NY: In Syracuse, the electric furnace proposition is just before us and for my own information I recently ran a test on a single phase furnace operated from an 11 000 volt 25 cyc'e line, to determine the input and power factor con litions on a furnace of the arc type used for melting cold scrap and producing high grade all by steels On the cold meiting process the secondary voltage is 220 volts and on the finishing heat it is 110 volts The power factor on the 220 volt process varied between 49.3 and 70.5 percent, the load ling between 80 and 730 kilowatts On the finishing part of the heat the power factor varied between 548 and 665 percent the demand being between 352 and 344 kilowatts I have a few charts swing fell 24 hour runs on this furnice running about six heats a day The average consumption per 2000 p unds of call scrap neted for one mor th's run of al- ut five beats a div. was about 735 ko watt Fours

With special reference to the surge to bang hihon of large are furnaces for load regulators. I think it would be interesting to know at what rate the furnice com any is charge! for the energy used by the furnice

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MR FS Cosy Detroit The electric furna e is of great interest to many of our companies and it strikes me that in isen ing any propaganda, a body as nation ly recognizi as should be certain that the staten ents in a le are quoti lar e nditions. The various minufacturers of cle tri Lave made certain statements in regard to the possibility of the manufuture of ele tric steel and steel castieng As the gentle ran who read the resort stated, conditions vary so greatly that it is not possible for anybody who is e ntemi Tating the sale of

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