432 THE COLLIERY GUARDIAN. March 2, 1917. There were many quack remedies upon the market. The advertisements stated that they were cure-alls—like all quack remedies—but he would hesitate before adding any such mixtures to boilers. If precipitation was found by analysis to be necessary, then the proper place for the precipitate was outside the boiler. The boiler was for 'generating steam, and, if one had to preci- pitate within the boiler, it most necessarily followed that the boiler must be sludged frequently in order to get rid of the sediment. That was an additional loss. The money spent in fake remedies would pay a handsome return upon invested capital in the erection of a suitable and efficient apparatus. At works where there were several pumps and engines at work, large and small, each exhaust pipe delivering spent steam into the air, some might think it an abomin- able nuisance, and others' that it was a pity that the waste heat was not recovered, and also the condensed water, which, one was told, was not suitable for boilers. It was a great source of economy if the waste heat at the works could be harnessed and led to a suitable place where it could be condensed by the boiler feed water. The result would be threefold, for, by condensing the steam, the feed water would be heated, and, conse- quently freed to a more or less greater part of temporary hardness, and the condensate would be most suitable for steam production. The latter must, however, be free from’ oil particles. The lubrication of the engine cylinder wras at a minimum, so that there was no room for thinking that, if more care were taken in lubrication, there would not have been any oil showing on the sur- face of the water. The thin film which one could see could cause a lot of trouble, and might soon be a danger. With the continuous boiling and continuous agitation of the water, the oily filament became divided impurity were easily removable. He did not think that it was of any benefit to use the barium hydroxide to precipitate the sulphate of sodium, as, by so doing, the sulphate was precipitated as barium sulphate, and the sodium remained as soluble sodium sulphate. The process would probably, in the case of magnesium sulphate, be rather costly, and, in fact, prohibitive. He mentioned the reaction with barium as it no doubt would appear to simplify matters considerably. Mr. Diamond exhibited a sample of sodium sulphate which had been taken out of the sludge pipe of a steam boiler which was supposed to be sludged every day. He stated that he had had several pipes cut open, andxthat the deposit which he found consisted of lumps of practi- cally pure sodium sulphate. With a water of 35 degs. hardness circulating in a condenser for making concen- trated liquor, that was the deposit. About 40,000 gals, flowed through the pipe every 24 hours, so that it would be rather impracticable to soften every particle of water used. Discussion. The Chairman (Mr. G. A. Phillipson) regretted that Mr. Diamond had not included in his paper some refer- ence to iron salts. He thought that many boiler troubles were caused through not getting hold of suitable water in the first instance. Ferrous sulphate, in particular, behaved just the same as a free acid in the boiler. Ammonia was apt to cause corrosion and pitting. Mr. Diamond assented to the suggestion of a member that it was a great advantage to use the same water over again in a coke plant, after cooling it. A member remarked that he thought that all coke plants ought to be provided with a water cooler, and the quench water ought to be used cold. THE GAINEY NON-CUMULATIVE VISUAL INDICATOR. A useful addition to colliery equipment has been introduced by Mr. H. H. Gainey, mechanical engineer to the Dunkerton Collieries Limited, near Bath, Somerset- shire, in the form of a non-cumulative visual signalling apparatus, which has been installed at the Dunkerton, Radstock and other collieries in the Bristol district. Many of the signalling devices used by colliery winders and others to take instructions for lowering and pulling up the cage, etc., are handicapped by the pointer having to start from zero and then work on after the first signal, until the pointer has travelled around the dial before it returns to zero, so as to give the winder a true guide for each signal. Owing to Government interven- tion several designs for a non-cumulative signal have been put upon the market, but for simplicity and neatness in detail the Gainey apparatus possesses advantages in its lack of intricacy, whilst the solid nature of the parts ensures freedom from irritating and costly items of replacements and repairs. The device, which is shown in the illustrations, works on the ratchet and catch principle, with a small air release to ease the action. A. ratchet wheel 5, to which a pointer is attached, is advanced, step by step, by a driving pawl 31, against the action of a spring tending to restore the pointer to the position required on the dial, when the ratchet wheel is retained. Means of a simple nature are provided for disengaging this retaining pawl from the ratchet wheel, so that the pointer returns to zero position, cancelling the previous signal. This disengagement is acted upon by a dashpot 20, so that the retaining pawl 7 cannot be again disengaged from the ratchet until sufficient time has elapsed to enable the fresh 9 2 10 30 32 3 < 33 18 26 26 23 25 19 13- 20 8 51, Ba 34 4 x A® / 3 24 Fig. 1.—Front Elevation and Section. 13 9 28 18 27 26 ! j 26 23 20 22 21 25 j / 7a I 24 Fig. 2.—Rear Elevation. into small globules of oil, which, in their turn, came into contact with precipitated salts, which solidified upon the boiler tubes, forming a most dangerous medium for burning or overheating the boiler plates. To overcome that danger, one must get rid of the oil. There were several methods of so doing. By making the exhaust steam come into contact with a baffle plate oil separator, 75 per cent, of the oil contained in the steam was separated, the remaining 25 per cent, being carried for- ward. The latter must be afterwards treated. Accord- ing to Redsdale Ellis, the oil passing in the steam was. in such minute globules as to measure about 0*00005 in. diameter. When greasy oil was used in boilers, the surface water should be frequently drawn oft, by means of a cock fixed on the front plate, to get rid of the greater part of the oily layer. The most efficient means of clearing the water of oil was to treat it in a water- softening plant, the means used to rid the water of objectionable hardness at the same time removing any oil film or globules, the oil surrounding the particles of lime or chalk, or, by saponification with the alkali, being afterwards susceptible to efficient filtration. There was a process of separating oil from water by electric treat- ment. . He did not know what success it had had, but it had been reported to work satisfactorily. It was stated that, by the Davis-Parrett electrolytic oil separation, an efficiency of 98 per cent, could be obtained, and the actual amount of oil remaining in the water was less than one part in a million. The process was said to be far cheaper per 1,000 gals, than other methods. Really, the operation resolved itself into the production of a basic ferrous precipitate, which was electrically absorbed by the oil globules and precipitated. Barium hydroxide had been used to precipitate the sulphates contained in water. It was of value in precipitating magnesium sulphate. The reaction which took place was that barium combined with the sulphate and formed an insoluble precipitate, which settled . out, and the magnesium was collected into the hydroxide, which was also .insoluble, so that, together, the reagent and the Mr. Diamond later mentioned pools of water at one colliery which were so full of ferrous salts as to render useless a wire rope which had inadvertently been left in the water. Mr. Duncan averred that he had come across pit water from a colliery in Scotland which was so rich in ferrous sulphate that he used to supply it to the local doctors for use as iron tonic. The total solids amounted to about 600 grains, including 120 grains of sulphate of iron and 70 grains of magnesium. There was a flow of several • thousands of gallons an hour which lasted for several months. A vote of thanks to Mr. Diamond concluded the meeting. Control of Mines.—Mr. S. H. Hunt has been released by the board of the London and North-Western Railway Com- pany to act jointly with Sir Richard Redmayne as assistant to Mr. Calthrop, the Controller of Coal Mines. Mr. Hunt is commercial assistant to the general manager of the London and North-Western Railway Company. The Parliamentary Secretary to the Board of Trade will speak for the Controller in the House of Commons. Tax on German Coal.—In submitting the. new German Budget, Count von Roedern, Minister of Finance, indicated the new taxation. Among other matters, he pointed out the great value of the coal produced in Germany and imported into Germany, which he had estimated before the war at 2,500 million marks. He emphasised that the idea of taking over the coal mines by the State had been rejected as impos- sible. After stating that Germany could safely rely on her own production of coal, and even on having coal for export during normal times, he said that coal could be taxed the more readily as the prices at home during the war as com- pared with those in foreign countries were comparatively low. The average price in Germany, he said, was 15 to 18 mk., while Great Britain paid 20s. to 30s. per ton, Italy .over 300 lire, France in November 125 to 150 fr. for house coal, and North America 6 to 7 dols.; so that “ an average tax of 2| mk. on coal and 80 pf. on lignite was not too high.” signal to be completed. The retaining pawl is disengaged from the ratchet wheel by means of a link pivotally connected and operated by a cross-shape lever 2, this link being displaced, for disengagement, by the mechanism operated by the above lever. The wire 1 by which the signals are given is connected to the arm of the centrally pivoted four-armed, cross-shaped lever referred to, this arm causing the bell to be sounded by the action of a pivotal striking hammer; and the ratchet wheel is shown which turns backward, causing the pointer to return to zero after the desired signal is given, the retaining pawl preventing its return by engaging the ratchet wheel until automatically released. At the outer end of the cross-shaped lever a weight is suspended by a wire 35, which tends to bring the cross- shaped lever to its normal position. To retard the cancellation of a signal, an air-cushioning appliance 19—24, is provided, which consists of an external inverted cup closed at the top and adapted to slide vertically up and down, telescopically, in relation to an internal inverted cup, which is open below and closed at the top except for a central air port. When a fresh signal is given the cross-shaped lever turns on its pivot, causing the link to pull the retaining pawl out of engagement with the ratchet wheel, thus permitting the spring of the latter to return the ratchet wheel and pointer to zero, whilst the air cushion prevents the link from immediately re-engaging the lug 10, the escape of air giving sufficient time before the link catches the lug to enable the wire to be again pulled if the signal requires more than one impulse, cancellation being prevented until a desired signal has been given. Sale of Colliery Timber.—Messrs. Stooke and Son 'an?e instructed to offer for sale by auction at the City Arms Hotel, Hereford, on Wednesday, March 4, at 2.30 p.m., in suit- able lots, timber and poles suitable for colliery purposes. Particulars may be obtained from Messrs. Stooke and Son, land agents, surveyors, and auctioneers, Hereford.