NATIONAL GAS ENGINES.

Progress, Volume II, Issue 2, 1 December 1906, Page 68

NATIONAL GAS ENGINES.

One of the most important engineering developments of recent years has undoubtedly been the introduction of suction producer-gas plant, which, owing to its increased economy m working, is creating what may be described as practically a revolution in gas - engine driving. Realising the future of the producer, the National Gas Engine Company have devoted considerable attention to its improvement, and their plant is at present amongst the best in the market. The great advant age of the suction producer over the older form lies in its very low first cost, the absence of a gasholder, the ease of starting, and the long period of time during which the producer can run without any attention whatever. The cheap gas of the older pressure producer was not obtained without considerable attention to the plant ; and consequently the power at which pressure plants began to be applied ranged much higher than those at which suction plants apply. It was rather unusual to associate pressure plants with any gas engine below 50 h.p. ; whereas now engines of 30 h.p. and lower are often operated by suction gas. Where larger powers are required, suction plant presents many advantages over the pressure type ; and the increase of power and dimensions is steadily proceeding. Suction plants are now made by the Company as low as 10 and as high as 300 h.p., and will soon be constructed to practically any power, in suitable units. The plant can be used in combination with a gas engine connected directly with it. The suction caused by the outstroke of the piston is then used to draw

air through the fire m the gas generator, but the plant will work equally well if the air is supplied by a fan or blower. The gas is made by passing a mixture of superheated steam and air through incandescent fuel m the generator, the fire being made with small anthracite peas, or small clean coke. In special cases other fuel can be used. There is no external fire, and the gas is made as quickly as it can be consumed. An important feature of this plant is that it has been designed on the heat regenerative principle All the air used for producing the gas is heated by waste heat from the body of the gas generator. The superheated steam required for making the gas is likewise produced by waste heat. The fuel which is to be converted into gas is also heated by waste heat before it reaches the combustion zone. Throughout the apparatus the loss of heat is therefore reduced to a minimum, and the efficiency is exceptionally high. When an engine works the suction plant, the engine itself governs the rate of gas production to suit its varying consumption. No surplus gas can then be made and as there is a partial vacuum in all parts of the plant, and in the piping while the engine is working, there cannot be any escape or waste of gas. The special feature of the " National " producer, which the Company claim gives it a marked advantage over suction producers, lies m the regulation of the water supply. This we learnt, is their own patent, and is applied only to the " National " engines. A large portion of the tools now running in the Wellington Works is driven by means of these producers A7O horsepower engine, driving the machinery 111 one of the large bays, is running under suction plant with gas produced at the rate of 2d. per 1,000 cubic feet. This is, of course, of a much lower quality

than the ordinary town gas, but a careful computation has shown that with the suction plant, gas can be made for yd. which will induce the same power as the town's gas at 2s. 4d. per 1,000 feet. It is estimated that when made the quantity of gas equivalent to 1 ,000 cubic feet of the ordinary town supply costs from 70 to 75 per cent, less than ordinary town gas at 2s 6d per 1,000 cubic feet, including fuel, labour, and repairs. The result is still more striking when the town gas is dearer. With any engine of good make, suitably adjusted to work with suction plant, the consumption of small anthracite is about 1 1b , and of suitable coke about i£lb per b h.p. hour. No visitor to the Wellington Works can fail to be struck with the extreme order and cleanliness which exist in every department, and the evident effort on the part of the management to provide every possible comfort and convenience tor their employees In the grounds outside the works a spacious dining hall has been built for the sole use of the workpeople. Each man is provided with a numbered can to hold his tea 01 coffee, and any victuals which he may wish cooked. This, on entering the works, he places on his numbered seat, and on the dinner bell sounding all he has to do is to go to his place, and there he finds whatever he has left, cooked, and ready for consumption. About 300 workmen have their meals here every day. Lavatories and all conveniences are provided ; the hall is heated by gas, and there are also comfortable fires — Implement and Machinery Review.

Piofessor Dewar states that the new chemistiy has shown beyond question that we have on eaith the same elements that are found in the sun.