Kinematograph year book (1944)

Film Exhibition and Kinema Technique. 219 if it is intended merely to instal the plant as a stand-by installation in case of a breakdown, the feeling of security that it engenders will be worth the capital outlay. Another argument in favour of the installation of the independent plant may be disregarded during the war, but in normal times it affords its possessor the opportunity of almost unlimited illumination for exterior and interior publicity in addition to the usual utility lighting. It is this flexibility in its use combined with economy of operation which is its most important asset. From the above it will be appreciated that the installation of an independent plant should be one of the post-war matters to be considered. It is difficult nowadays to give installation costs — new equipment is unlikely to have been supplied in recent years except under Board of Trade permit, but generally speaking, current can even now be generated at from 20 per cent, to 50 per cent, lower than the mains charges. It is quite possible to generate current at a total cost of less than Id. per unit given a reasonably large output. In addition to the actual purchase price of the equipment, the exhibitor who is exploring the advantages of the independent plant, must remember that it will occupy considerable space and will also entail specially constructed storage tanks for the fuel, and possibly a little more attention, but even so, if the charge for electricity from the mains exceeds 1 ^d. or 2d. per unit, there will be a considerable saving. War operation has proved the reliability of the independent plant for, notwithstanding attention by less skilled labour than formerly, shortage of replacements and other difficulties of maintenance, very few break-downs have occurred among these kinema equipments. The war has provided manufacturers with a considerably extended experience of the building and operation of these plants, and at no future date it may be reasonably hoped that the exhibitor will share in the benefits derived from the war effort. National Gas and Oil Engine Co., Ltd. — National oil engines, vertical and horizontal types, give silent and economical running, and are ideal for kinemas. One installation, comprising a 12 kw. dynamo, is claimed to have effected a reduction in costs of £39 per annum ; the normal load of this equipment is 8 kw. Another equipment recommended is a 3-cylinder unit developing 25 b.h.p. at 1,000 r.p.m. This firm also specialises in gas engines for kinemas, an interesting example of which is a 3-cylinder engine having an output of 27.30 b.h.p. at 1,000 r.p.m., and suitable for a 15 kw. plant. It will run at three-quarter load on a consumption of 8,720 B.Th.U. gross per b.h.p. hour. Assuming gas is obtainable at 4d. per therm, the fuel cost is 7d. per hour, which is comparable with the diesel engine. After making due allowance for other charges, such as lubricating oil, stores, interest and depreciation, the running cost would be considerably lower than the cost of mains electricity in most districts and the owner would have a reliable independent lighting set. In a new type of gas engine the compression ratio is raised from 6 : 1 to 15 : 1 and the B.M.E.P. is increased from 66 to 110 lb. per sq. in. The advantages over previous designs for an engine of the same physical dimensions are, firstly, an increase in power of 50 per cent. ; and, secondly a reduction in fuel consumption (per b.h.p. hour) of 35 per cent, where power rates for gas operate. British Films, Ltd. — The development of the " Brimain " Power Unit, produced and marketed by British Films, Ltd., 199, Piccadilly, London, W.l, has forged steadily ahead in 1943. These units, which are specially designed to eliminate instability and surge were primarily introduced for the operation of Portable 16 mm. Soimd Film Equipment where the lamp switching was liable to cause considerable voltage variation to the detriment of other equipment in circuit. The "Brimain" incorporates a petrol driven 4-stroke motor of advanced design and generates 1.25 kva. at 3,000 r.p.m. The layout of the unit is extremely clean and every part is easily accessible. Carrying handles are provided for easy movement from the light van in which the unit would normally be transported.