WATER SUPPLY OF LONDON
Schemes For Its Improvement and Increase—Sources of Supply—A I ypical Pumping Station.
(Special Correspondence of FIRE AND WATER ENGINEERING.)
LONDON, May 17, 1910.
The need for safeguarding the future water supply of the metropolis of London is perceived by our water authorities and a scheme is being got out which provides for a supply of water by means of huge reservoirs throughout the Thames valley, sufficient to give by the year 1916 a thirty days’ supply for that population which it is estimated will then live in London. Twenty years is required for the completion of the scheme. 1 he total cost of the works to be provided is about $55,000,000. Of course a bill must be carried through Parliament to secure this. At the present time London’s water authority, the metropolitan water board, supplies daily about 7,000,000 people with water utilising the services of 4,000 men, and giving a daily supply of as much as 240,000,000 gallons. Six years ago there existed 57 storage reservoirs; to-day there are 62. The acreage in that time has grown from 866 to 1,500 while the capacity the board is able to store in reservoirs has grown from 4,000,-000,000 gallons to 9,000,000,000 gallons and 6,255 miles of water pipes are used.
The capital debt of the board is now $244,.160,000, and the annual interest charge $7,351,-500, which is equivalent to 8.6 cents per 1,000 gallons supplied. That this charge is likely to increase may be inferred from the fact that at a recent meeting of the board, when the future water supply of the metropolis was under discussion on the report of the works and stores committee, two extensive schemes for increasing the general service were put forward, one entailing an estimated outlay of $41,985,000 and the other, which was recommended for adoption, and which contemplates the construction of reservoirs in the valley of the Thames in progressive stages, being estimated to cost $31,368,500.
The adjustment in water rates since the metropolitan water board came into control has been a matter of some complaint, particularly among large business firms, which use comparatively little water, but, owing to the system adopted of charging in proportion to the rateable value, and not to the quantity used, have to pay an altogether exorbitant fee for their supplies. On the other hand, the board, by linking up and extending the different systems, has materially improved the general service and obviated the risk of a water famine, which periodically threatened to occur during dry summers, especially in the east end of London, under the old regime. The board has, moreover, minimized as far as possible the continuance of the old practice of “cutting off” as a means of enforcing the payment of water rates by the substitution of legal proceedings, and this more lenient and also more sanitary method appears to have worked out fairly satisfactorily, since the collections in the last financial year amounted to $176.72 of the total amount due.
The four main sources from which the water is obtained continue as before—namely, intakes from the Thames and the Lea, the gravel beds adjoining the main stream of the Thames, and natural springs and wells sunk in the chalk strata in the Lea valley and at certain points south of the Thames. In 1908-1909 the Thames furnished 57.27 per cent, of the total, as compared with 55.98 per cent, in the previous year, and the proportion taken from this source and from the Lea apparently tends to increase, while the supply from springs and wells is diminishing. The eastern district; for instance, supplied 21.39 per cent, more from the Lea than in the previous year and 25 per cent, less from the wells, while the New river increased its supply from the Lea by 1.65 per cent., but decreased it from the wells by 21.88 per cent. The increased storage facilities have, however, practically eliminated the dangers attending the use of raw river water. Experiments with artificially infected samples taken from the Thames and Lea show that 99 per cent, of the bacilli died within one week. and storage for four weeks before the water goes to the filtration beds affords, it is stated, ample security against any danger. The present policy of the board appears to be to steadily increase the storage capacity, and so make use of flood water which would otherwise run to waste, and this, though costly enough, is certainly more economical than the scheme once so strongly advocated of obtainthe whole supply from Wales on the lines oi the Birmingham waterworks.
A specially interesting pumping station in connection with London’s water supply is the Hammersmith one and it is interesting not only from the fact that it has to pump water up to very high levels in tile London residential areas, but because it illustrates the evolution of pumping machinery here from the early years of last century down to the present time. The requirements of increased population have demanded an increase in the pumping plant. This new part of the station is now nearly ready. The new engine house is 112 x 42 feet, with its foundation carried down into London clay.
The working floor is composed of concrete slabs reinforced with expanded metal, resting on rolled joists, and covered with red flooring tiles. A 12-ton traveler spans the house, and is approached by ladders leading to a gallery which extends along the whole length of the east side of the house. The engines in this house are known as Nos. 14 and 15. They are identical in every respect except as to the size of the pump plungers. They are tripleexpansion inverted engines of the marine type, each with three double-acting pumps, the pumps being placed directly beneath the cylinders. Four side rods on the crank shaft connect each piston crosshead with each pump cross head. The cylinders are, respectively, inches. 35 3/8 inches and 60 1/2 inches in diameter by 4-foot stroke. The high and intermediate cylinders are jacketed with full-pressure steam and the low-pressure cylinder with steam re duced to 50 pounds pressure. The connecting rods are 2 1/2 times the length of stroke, viz., 10 feet long. There are two flywheels, each 15 feet in diameter, to each engine, and these are placed outside the bedplate. Thus there are no overhung cranks.
The crank shafts are of forged steel, built up of three identical units coupled with taper bolts, the journals being 13 1/2 inches in diameter. A barring engine is fixed for starting each engine, and has an automatic throw-out, which disengages the gearing as the engine gathers way. The steam pressure is 150 pounds, and the saturating temperature is increased by about 120 degrees F. of superheat. A reheater supplied with full-pressure steam is provided between the high and intermediate and between the intermediate and low-pressure cylinders. The plungers of No. 14 are 14 7/8 inches in diameter, and at 30 r.p.m. this engine should deliver 7,000,000 gallons per day to the Shootup Hill zone. The plungers of No. 15 are 17 1/2 inches in diameter, and at 30 r.p.m. this engine should deliver 10,000,000 gallons per day to the Barrow Hill and Willesden zone.
One of the three delivery pipes from each engine is connected to the condenser, so that one-third of the water delivered should pass through the condenser. The condensers have riveted steel bodies and each contains 768 brass tubes inch in diameter. The three delivery 33-inch a into merger engine each from pipes steel main leading to the exchange mains in the pipe chamber. The exhaust from tile lowpressure cylinder passes first througli an oil separator to extract the bulk of the oil. then through an exhaust feed heater, where it gives up its remaining heat to the feed water on its way to the economizer, and afterwards to the condenser. The air-pump delivers the condensed steam to an oil eliminator in which the remaining oil is removed by the use of a coagulant, and by passage through beds of wood wool and quartz sand. The boiler house joins the engine house on the east side, and contains four Lancashire boilers each 30 feet by 8 feet, each having two cylindrical lines 3 feet 3 inches in diameter. The boilers are designed for a working pressure of 155 pounds per square inch above atmosphere. In each of the flue tubes a length of corrugated tube 7 feet 6 inches long is inserted, to take up any differential dilation as between the flue tubes and the shell. In each downtake there is a superheater with a tube surface calculated to provide a superheat of about 120 degrees F.
A hot forced draught system is provided for the new boilers, and economizers are installed. The steam and feed pipes are all made of Mannesmann steel tubes, with screwed flanges, into which the tubes are expanded. The pipe from each superheater is only 4 inches in diameter. The maximum diameter of the main steam pipe is 6 inches and the pipe conveying steam to each engine is 4 inches in diameter. These small sizes are adopted in order to maintain a high velocity of flow with the object of avoiding loss of superheat by radiation. The feed to the boilers is ordinarily pumped through the exhaust heaters and the economizer by pumps coupled to the air-pump levers of the main engines. A feed pump is provided in the boiler house for use in emergencies. The feed on its way to the boilers is measured by a hot-water meter.
Coal for the new plant is stored in five reinforced concrete bunkers adjoining the boiler house, their aggregate capacity being 600 tons. They are filled by an extension of a previously existing transporter by which the coal is unloaded from the barges in the river. The coal is transported in skips, each containing 23 hundredweight, which are lowered by the transporter on to a weighing platform. After being weighed the skips are picked up by an electric transporter and run along a beam until the skip is over the bunker in which it is to be dumped, when an automatic dumping block tills tile skip. The current is taken from the borough mains, but as that current is alternating current of 110 volts and 50 periods a motor generator in the engine house basement converts it to direct current of 440 volts. The current is picked up by a trolley arm from copper conductors attached to the beam of the transporter.
Water Report of Norwich, Conn.
Fifteen miles front Long Island Sound, at the head of navigation on the Thames river, the city of Norwich, Conn., is located at the confluence of the three small streams by which that river is formed. With a steadily increasing population. numbering, according to the latest census, 17,251. and important industrial and commercial interests, the city’s water supply has been a source of solicitude to the municipal authorities, who have bestowed careful attention on its development to keep pace with the city’s growth. Superintendent Edwin L. Barnap reports the year ending March. 1910, as having been a busy period, a large amount of work having been accomplished and important improvements effected in the service. Several brooks and springs, 1 1/2 miles from the busines scenter, the waters of which are impounded in a reservoir of 450,000,-000 gallons capacity, which has recently been greatly enlarged by the erection at Meadow Brook of a new dam. constitutes the source of supply. The svstem operates by gravity, the elevation of the reservoir insuring a satisfactory bead. Distribution is effected by means of 51.71 miles of mains. The total number of hydrants served is 450. The cashier reports total receipts for the year of $70,708.72, of which $66,831.68 was received for water rates. The disbursements for maintenance and operation were $29,-120.40, interest on bonds adding $10,350 to this, making total expenditures $39,470.40, and leaving a net income to the city of $31,238.32. The total cost of the works to date, including $78,900 recently disbursed in connection with the Meadow Brook dam improvement, has been $1,159,918.62, and there is an outstanding net bonded indebtedness of $215,000.
Kearney, Neb., will vote on a proposition to purchase its water supply system for $125,000 and operate it municipally. Kearney obtains its water from wells, which have a daily average capacity of 2,000,000 gallons.
Niagara Falls Industrial Plant Fire.
One of the worst fires the Niagara Falls, N. Y., fire department has had on its hands for some time occurred when the Hooker Electro Chemical Company’s plant was recently threatened with complete destruction. The works covered seven acres of land and in many of the buildings expensive machinery was installed, but by the hardest kind of work, involving considerable personal risk, the firemen succeeded in saving some of the most important of these buildings, although in spite of this the damage amounted to upward of $300,000. Defective electric connections in the new cell house are blamed for the fire, although the cause had not at our last account been definitely determined, but once started, it made rapid headway, and when, in response to alarms sent in by street boxes and telephone, Chief Otto F. Utz arrived with his firemen, the building in which the fire originated was a mass of flames which had already attacked the adjoining new cell house. A brisk wind was fanning the flames and the old bleach house, a big frame structure, was next threatened. The chief promptly sent in a second alarm, bringing every company in the city but one to the fire, and the fight to prevent it wiping out the entire establishment was on. The firemen were handicapped by low water pressure at the start, about to feet being the range of a plug stream, while the steamer, after working well for three hours, and furnishing two good streams that were a great aid in saving the new bleach house, broke the crank shaft of its pump and was out of business for the rest of the fight. The old bleach house speedily met its fate and the fire then threatened the chemical laboratory, in which was stored a varied assortment of explosive stuff, and the repair shops. The firemen succeeded in saving both these buildings, although they were considerably damaged, and they also saved in a range of the fire huge brine tanks intact and five that were somewhat the worse for their fiery experience. The office building and the evaporating building were likewise saved, about three acres in all being burned over. In their efforts to save the laboratory building a number of the firemen, regardless of their own safety, ventured too close to the burning bleach houses anti were overcome bv the escaping chlorine gas. They were rescued by their comrades and received medical attention. One fireman, stationed on a roof, went down with it when it collapsed, but was dragged out from the floor below. Captains Power and Pfetsch, who were among those overcome, were removed after receiving medical attention, the automobile of l ire Commissioner David Isaacs, who was an interested spectator, being pressed into service as an ambulance. Assistant Chief Dick Miller did heroic and excellent service and Assistant Chief George Wood, who is attached to the only company that was not called to the fire, was on hand and took part in directing the work of the firemen. It was, from first to last, a hot and ugly fire, the big steel beams and girders warping and bending under the intense heat, while falling walls and stifling chemical fumes added to the disadvantages under which the firemen were compelled to labor for six hours. Arrangements for the rebuilding of the plant were under way before the last of the firemen had left and the hands will be kept employed at salvage work and removing the debris so that they will suffer the least possible loss. The fire served to emphasize the weakness of the Niagara Falls firefighting equipment, for which at least two more engines are needed, and the experience of the firemen and public comment will probably ensure their purchase.
Newark, N. J. Firemen Inspected.
Following their inspection of the Newark, N. J.. firefighting force and equipment, the fire commissioners and their guests reveiwed the incidents and observations of the trip at a dinner in the evening of May 27.
As to the condition of the department, the members of the inspection party had nothing but praise, but the limitations under which it was working were recognized. The need of extending the fire limits to afford more adequate protection to the outlying districts was emphasized, and when the matter of service came up, indorsement of motor-driven apparatus was given.
President Thomas E. Burke, of the Fire Board, presided at the dinner. Mayor Haussling occupied the seat of honor. The fire and police commissioners, members of the aldermanic board and other city officials and guests, about twenty in all, made up the party.
At the outset Mr. Burke made a plea for consideration in the matter of appropriations for fire purposes. The budget of the department, he said, was usually the victim when any paring of appropriations was to be done to keep the taxes down. The average taxpayer, who was not closely in touch with requirements, was apt to protest at the expenditure of large sums, but those who know conditions of the department would appreciate the needs. That was one of the objects in inviting those who had to do with city affairs to see for themselves.
Alderman Charles L. Ingraham, president of the public buildings committee of the Common Council, expressed his appreciation of the work of the commission and said that lie would support any request of the fire board for additional funds before the finance committee. He recognized that splendid as the present force and equipment was. it was not keeping pace with the growth of the city. The Forest Hill and Clinton sections needed fire houses. Mr. Ingraham declared, and a site had been selected for the location of the latter. Then the alderman said that the city had probably purchased its last horse-drawn fire engine.
Several other speakers spoke for the gasoline engine, and the opinion of Mr. Ingraham seemed to be pretty nearly unanimous. There were a few qualifications, however. Mayor Haussling, when appealed to looked upon the plan favorably. but counseled not too rapid a change or the adoption of the idea that gasoline was the panacea for all ills.
The entire fire and police department of Mattoon. Ill., has been laid off indefinitely, there being no funds in the city treasury with which to pay the salaries.