HEAT OUTPUT AND RATE OF COMBUSTION. 56. Coal burned per hour, average for all heaters for 24 hours, pounds... 57. Coal burned per square foot of grate per hour, average for 24 hours, pounds.... 58. Heat usefully employed, calculated, B. T. U. per hour.. 59. Horse power of heaters, average for 24 hours.... EFFICIENCY RESULTS. 41.3 72.3 403,000 705,000 12 21 28 62 850,000 403,000 705,000 83 83 2,570,000 438,000 83 60. Horse power during six hours, drafts on...... DISCUSSION OF THE EFFICIENCY RESULTS. The figures of the last two lines point. to the exceptionally high over-all efficiency of 83% for the heaters. It is proper to give close scrutiny to these results, in order to detect errors in methods used, if such exist. But it may be pointed out in advance that one feature of this installation is excellent in design, namely the placing of the heaters in the .1,110,000 85 air chambers where the radiation from the setting is usefully employed in heating the air. The efficiency of the system can be determined from the assumed heat loss from the building, which can be calculated from known constants with reasonable accuracy, and the results obtained will serve as a check on other methods, at least. Following are the details of the building dimensions and constants used in the calculations: BUILDING DIMENSIONS AND HEAT LOSS CALCULATIONS, 67. Volume of building, cubic feet.. Methods of Dripping Steam Mains TOGETHER WITH ARRANGEMENT OF SCA LE POCKETS AT RADIATING SURFACES TO SUIT VARYING CONDITIONS. Various methods of dripping the ends or low points in steam mains are shown in Figs. 1 to 6, inclusive. Figs. 7 to 11, inclusive, show the methods adopted in obtaining scale pockets at the return ends. of pipe coils and radiators. The particular method that is used is a matter of choice or as may be necessitated by the building construction or location of radiating surfaces. In Figs. 1 to 4, inclusive, the steam supply main is carried full size or nearly so up to its drip point where a scale pocket and thermostatic float, or other kind of trap is located. The gate valve shown in Fig. 5 may be closed, and repairs easily made to the trap at any time. Supply Not less than 22 Fig. 6 shows a loop seal, and modifications of this are shown in Figs. 1 and 3. Loop seals may be unsightly in appearance when installed in offices or it may not be possible to obtain the proper depth of seal under some conditions. The further disadvantage of the loop seal is in its liability to stoppage. It is apt to Supply Retvrn FIGS. 1-4-METHODS OF DRIPPING ENDS OR LOW POINTS IN STEAM MAINS. freeze on exposed work, and only serves Drip from Supply to increase the number of pipes and the maintenance. The pipe forming the loop seal should be of liberal size and some provision made for draining the seal and cleaning Not less than Supply By-Poss FIGS. 5-6-ADDITIONAL METHODS OF DRIPPING ENDS OR LOW POINTS IN STEAM MAINS. out. A plugged tee or a nipple and cap may be used for this purpose. The depth of seal necessary is determined by the difference in pressure existing at that point, being about 2 ft. in depth for each pound difference in pressure. Loop seals are an advantage when the system is started up. As steam is turned on and enters the cold mains and branches it condenses rapidly and this first water of condensation is then quickly passed through the large areas afforded by the loop seals. In the event of stoppage the loop seal may be by-passed by opening the valve on the crossover above. Arrangements Adopted for Ventilating the New York Subway Extensions. In view of the agitation that arose over the ventilation of the New York subway when it was first opened and the evident necessity for better provisions for a proper air supply in the subway extensions, the following description, by F. Lavis, published in Engineering News for November 5, 1914, will be read with general interest. Every effort has been made to so design the new subways, that the excessive heating which occurs at times in the summer in the present subway may be avoided. The tracks are to be divided so that trains going in one direction will be in a separate tube or tunnel from those going the opposite way; by this means it is expected Bench Return Scale Pocket Skylight Coil фа Method adopted where space is close vnder a bench FIGS. 7-11-METHODS ADOPTED IN OBTAINING SCALE POCKETS AT RETURN to utilize the movements of the trains (the so-called piston action where there is only one track in a single tube) to push the air ahead and out through the openings which are provided for this purpose. The original subway is completely surrounded by an envelope of waterproofing, and it has been thought that this has prevented the dissipation of some of the heat generated by the motors, brakes, friction, etc., into the ground surrounding the structure. On the new lines waterproofing will generally only be used where actually necessary to keep out water, that is, below the ground-water line, in earth, and on the roof. Openings in the roof of the tunnel, with sidewalk gratings, are provided over the station platforms, and generally one about half way between each station and one at each end of the stations on the side toward the approaching train, these latter being expected to take care of most of the draft caused by the train, instead of allowing it to create a current at the platform and up the stairways. The dimensions and numbers of these openings have been so fixed that it is expected that the current of air coming through the gratings in the sidewalk will be barely noticeable to pedestrians. Fan chambers, which are all arranged so that they may be also used as emergency exits to the streets, are provided, one about midway between each station. They are so arranged that they will draw the air from the tunnel at points intermediate between the stations and blow it out through the gratings already described, thus, of course, drawing fresh air in at the stations. It is expected that the openings alone combined with the action of the trains will ordinarily provide sufficient ventilation, the fans being used only occasionally when circumstances require. The piston action of the trains in the single-track tube of the Hudson & Manhattan R. R. has been noticeably efficacious in promoting efficient ventilation, but except on the Fourth Avenue, Brooklyn line, where there is a parked space in the center of the street and where walls are provided between each track, it was not considered practicable to divide all the tracks of the new four-track lines so that each would be in a separate tube, on account of the difficulty of providing outlets for the center tracks. It would be impractical, of course, to provide openings in the roadway of the streets, and in order that the openings in the sidewalks might be used, the center wall only was built dividing the traffic going in opposite directions, but leaving the two tracks on one side in the one space. If this does not produce the required movement of the air, that is, actual propelling movement, not mere stirring up as in the present subway, the fans must be utilized to supplement it. Openings about 2 ft. wide and 8 ft. high are provided at every 10 ft. in the center wall as a means of communication between the two sides, and as refuge niches, and these may tend to reduce the piston effect to some small extent. Although this arrangement in the fourtrack section will reduce somewhat the positive piston action of the trains, it will be beneficial to the extent that it will tend to reduce the air resistance, which has been shown to be by no means a negligible factor in cost of operation in single-track tubes, though this cost may be offset by the benefits of more efficient ventilation. The actual effect of all these different items and of the size of the cross-section both on the efficiency of ventilation, as well as the cost of operation, is something of which little is actually known, but in view of the enormous expenditures which are being made and which undoubtedly wilt continue to be made in underground railways for rapid transit, in subaqueous tunnels, etc., it is hoped that further experi ments along the lines of these already referred to and others of like nature may be continued. The object of the design of the openings has been to provide at the track level a space into which the air pushed ahead of the train may expand and be detained, instead of being pushed by, and then provide' an opening above through which it may escape to the surface, there being apparently little reason to doubt the efficacy of this proposed scheme. Current Heating and Ventilating Literature. Under this heading is published each month an index of the important articles on the subject of heating and ventilation that have appeared in the columns of our contemporaries. Copies of any of the journals containing the article mentioned may be obtained from THE HEATING AND VENTILATING MAGAZINE on receipt of the stated price. GAS FIRING Gas Fired Steam Boilers. H. E. G. Watson. Read before the Canadian Gas Association. On the use, management, care, etc., of such boilers. Ills. 3000 w. Am. Gas Ltg. Jour.-Oct. 19, 1914. 20c. BOILERS Down-Draft Heating Boilers. Osborn Monnett. Gives typical heating boilers and designs of furnace for smokeless operation, with tabulated results. Ills. 500 W. Power-Oct. 6, 1914. 20 c. Handy Data on Central Station Heating. Much of the work of the central station heating engineers is being simplified for him by the publication of tables similar to those given herewith, which are those used in the practice of J. C. Hornung, engineer, 111 West Monroe Street, Chicago, and published by him as a series of cards which are distributed to the trade. Table No. 1, for instance, is a compilation of co-efficients as used by him for estimating direct radiation, together with his rule for ascertaining the radiation required with low pressure steam, with vapor or atmospheric steam and with hot water. The other tables are devoted to the proper pipe sizes for various runs, etc., and these will be supplemented from time to time with additional tables. In addition to the data contained on the cards, on the reverse of two of them ate presented typical house installations arranged for service from a central heating station, one as designed for steam and the other for hot water. New Book. FUEL, SOLID, LIQUID and GASEOUS, is the title of a new book by J. S. S. Brame, F.C.S., instructor in chemistry at the Royal Naval College, England. The reading matter contained in the book is based upon a series of lectures delivered by the author at the Sir John Cass Technical Institute, at Aldgate. It is divided into four head PIPE SIZES FOR CENTRAL STATION HOT WATER SERVICES AND HOUSE EQUIPMENT DISTANCES GIVEN ARE IN LINEAL FT OF TWO PIPES ADD 10 FT FOR EACH PAIR OF ELLS OR EQUIVALENT DISTANC 40 80 120 RADIATIO 2 160 200 210 280 320 400 480 560 640 720 800 900 1000 1250 1500 2000 2500 3000 40.***22 22 2 24 60*222222 80......★☆☆** 14 2 2 2 2 2 24 24 21 1 |