Alberta Coals and Automatic Domestic Stokers

Laboratory investigation and questionnaire as sources of information. -- In 1942 the Research Council of Alberta decided to carry out an investigation on the suitability of Alberta coals for use in automatic domestic stokers; and funds for this work were provided by the Legislature in 1943, '44 and '45.

A building and duplex chimney were erected on the campus of the University of Alberta, and two hot-air house heating furnaces were purchased and installed. One furnace was equipped with an underfeed stoker and the other with an overfeed stoker.

Considerable preliminary work was done to establish the best methods for operation and control, and a standard test procedure was evolved. Subsequently twenty-three coals were tested, eighteen in the underfeed and eighteen in the overfeed stokers. Details of the tests are given later. It must be stressed that the investigation was designed to ascertain Alberta coals suitable for use in each type of stoker; no attempts were made to test the efficiency of either stoker, and no attempts were made to change the stokers or adapt them in any way for use with coals for which they were not primarily suited.

Valuable information was gained as to the characteristics desirable for stoker use, and as to the availability of such coals in Alberta. However, it gradually became clear that although it was possible to establish certain broad generalities it was not possible to classify all coals as definitely suitable or unsuitable for either stoker. A coal found entirely suitable, by test, for use in one stoker was found to have given serious trouble to a householder using it in a similar stoker. On the contrary, a coal found satisfactory by a householder might give trouble in the tests.

The size, fire bed temperature, and other conditions of the fire in a particular stoker, are influenced not only by the coal fired but also by the relation of the size of the stoker to size of furnace, and the relation of both to the heat requirements of the house as well as by the type of furnace. A coal may give satisfaction under the fire conditions of one installation and may be quite unsatisfactory in another. One installation may work best with one size of coal and another requires a different size. Moreover, successive deliveries of coal from a certain mine may vary somewhat in ash content and in clinkering characteristics.

It was therefore decided that, before proceeding to write this report, it would be well to send out a questionnaire to users of automatic stokers in order to learn what coals they burned and their experiences with these coals. The conclusions and opinions expressed in this report are based on the laboratory investigation and on the replies to the questionnaire