PHILOSOPHICAL INSTITUTE.

Press, Volume XLVI, Issue 7420, 20 September 1889, Page 6

PHILOSOPHICAL INSTITUTE.

HEATING AND VENTILATION.

it evening Mr S. Hurst-Seager delivered a lecture on "Modem Methods of Heating and Ventilation." The lecture Was under the auspices of the Canterbury Philosophical Institute, and took place in the Chemical Lecture Theatre at Canterbury College. The audience, not a very large one, doubtless owing to the inclement weather, included a number of ladles. Mr H. R. Webb, President of the Institute, made a few remarks by way of Introduction. Mr Skager said he trusted his audience would not infer from the title of his lecture that he could in so short a time at his disposal bring before them all the methods Invented for warming and ventilating our dwellings. It was not so necessary to wrote much of their attention to what had beea done, as it was to what ought to be done. Ventilation and heating had to t>e considered together. Before any scheme Cor the latter could be considered it was necessary to findouthowmuch air had to be heated. By the simple process of burning candles in closed jars he showed how rapidly the oxygen was absorbed. By repeating the experiment with primitive ventilation from the necks of the jars the candles kept alight, and again by supplyIng cold air from below and allowing the vitiated to escape from the top he clearly demonstrated the principle of ventilation and heating. The jars were supposed to represent difterent sized dwellings, and the candles the inhabitants. Tne experiment was to show what effect bid ventilation produced upon the occupants Of ill-constructea dwellings. He next explained the amouut of ventilation needed per hour in every room occupied, and how the Quantity was calculated. He explained also the use of various kinds of ventilators, and the difference between winter aud summer ventilation, besidee the mfluense exercised by the wind. He recommended as a wall ventilator a cone-shaped piece of metal, whicn admitted fresh air without the disadvantage of a draugnt. It was simple and might aasily be adopted. An ouclet ventilator, he observed, ought to be as direct as possible. Then, in addition to the amount ot air needed, care had to be taken as to temperature. From about 48 to 60deg was the heat, the latter for hospital sick wards. Continental hospitals had oi). Then purity was as necessary as warmth and quantity, and care should be taken to avoid scotched air. Another point was that of humidity, which was tested by a thermometer with a wet and a dry valve; 15 was a good average. It should not be lees than 55 nor more than 82. He then came to the different methods adopted for wanning air. They were three—by radiation conduction and connection. Here fallowed an experiment showing the Siuciple of heating by radiation, and c explanation that heating by conduction was by the heating of one particle by another. Liquids and Sees were bad conductors of heat. To heat them were applied the principles of connection. Radiation was also by means of open fire-places; radiation and connection by ventilating grates and dosed stoves; connection by hot-air pipes, hot water pipes, or hot steam pipes. He passed on to the modes oTiipplying the principles. In the matter of open fire-places it was necessary j ■tih+t. the Bides should be set at an angle of from 45deg to 60deg to act as reflectors. Open college grates were the most common. They had the disadvantage of square sides and large chimney opening. Register nates were invented as the remedy. They had an opening to limit the quantity of heat passing up the chimney. He had exhibited several samples of the register grate. - Those were the most commended which possessed fireclay sides •r tile sides, as the conductivity was very small, and the heat was consequently ' thrown into the room. The,best stove, however, was the one which by radiation and connection, and these two qualities were found in the ventilating stove called the "Municipal •tore." It .economised the fuel greatly. In dose stoves 75 per cent, of the fuel was utilised, while in open grates 90 percent, of the heat went up the chimney. People would not like to give up their open fireplaces he felt sure, but if they wished to •tody economy some other means must be adopted than of heating by open grates. Iron stoves were unhealthy on account of the extreme conductivity of iron. A pillar gas-stove, of which he had a sample, was an excellent one for heating, as it acted in a similar manner to that indicated. In respect to gas stoves, it was necessary for health that the products of combustion should not pass into the room, and the kind of burner was a point to be considered. Heating by hot air was a method which was adopted chiefly in large manufacturing placet*, where health was not perhaps the first consideration. He would therefore pass on to the next system, which was that of heating by hot water. By the use of a glass model he explained the principle of this system, and the manner in which the hot water was conducted from the boiler and back again, and emphasised its safety by pointIng "out that the pressure was only due to the height. There was no internal pjressore. Any steam which might create an internal pressure was carried away by the outlet pipe. In heating different floors the pipes were not to be perfectly upright from the lower to the top floor, or the water would rush to the top without heating the intermediate rooms. The upper room pipes should project beyond the lower, so that the water fills tine lower pipes first. The pipes ought not to be. placed open in a room, as the heat would generate unhealthy gases. The best methods were to have the pipes placed near an inlet of fresh air, or passed v chambers beneath the floors. Steam could be used at high or low pressure; JO, 40, 60, or 601b for manufacturing purpases. It never reached that pressure in dwellings where it was from 5 to 101b. The system was largely adopted in countries such as America and some parts of Germany, where it was very effective. There were disadvantages in connection with steam heating. One was that it required constant attention; the pipes often made a considerable noise called the " water hammer," which could be obviated by getting rid of the water as it was formed. The doing so would be expensive. The system, in fact, was wasteful aud expensive. It could only be successfully and economically employed when the hot water, could be thrown off and returned to the boiler. The system was more difficult to regulate than that of hot water. In the latter it could be done by the fire; in the former the temperature must be 212 degrees before the steam was of any service. This difficulty had been overcome in an ingenious way in Berlin by the introduction of a mixing chamber. In both systems the theory was the same, but the application-of steam was the more expensive, as doubtless the experiments shown would testify. -Numerous experiments were made by the lecturer to illustrate his remarks, and working model* were shown of the Iceland geyser, of Barlow's modification of the hot water system, and of the working of the system of -heating by steam. In conclusion Mr Seager said he did not expect his audience to remember all that had been told them Of the different methods and their application, but he had endeavored to enow that every work must be based on Nature's own laws.

- On- the motion of Mr Mkeson. whose remarks were endorsed by Mr Webb, a Tote of thanks was accorded to the lecturer.

Mr Srabkr, in acknowledging the compliment, returned his thanks to Professor Blckerton and Mr Page for the room and assistance.