Show ii ° t For Oirouth 1I I 1 I tv I HOW ELEVATORS WORK twoThirds of the Elevators of New York Alone Could Carry the Entire lop lalion of tho United States in a Day BY CLEVELAND MOITETT Five hundred thousand men ride in the elevators of New York city every day of the year and yet not one man of them in a hundred has more than the vaguest idea I how these shooting cars work As for the hundred thousand or so women who daily call out up ordown7 the percentage per-centage who know what makes the < < thing go would be shockingly small To get some more precise ideas aoout these vertical railways I went down the other day into subterranean New York into those wonderful modern catacombs where engines throb and electricity takes its birth under one of the great downtown down-town buildings which contains no less than thirtyfour elevators twentyone tor passengers thirteen for freight A strange and unfamiliar region is this where giant wheels belted to other wheels mako the foundations tremble and the air roar in ones ears We were c many feot below the level of Broadway We were breathing oil and steam Hero said the engineer to whom all this was as familiar as the schoolroom to its teacher here arothe boilers which supply steam to work the elevator pumps and to turn the dynamos Therearenine of them each eighteen feet lone and sis I > leet in diameter They burn 125 tons ot JI I I IIi II-i THE PUMPS coal a week winter and summer The seaeons make very little difference it is always the same down here 1 Now come this way and you will see how this steam makes the pumps send water up to the tanks at the top of the building 5000 gallons ot it a minute Say they work at full pressure half the time or four hours a day that gives 120000 gallons pumped up about200 feet which means nearly two hundred million foot pounds of energy a day to run the J elevators alone Not so bad is it And I the beauty of it ia that in doing this work t we use the water over and over again pumped into the tanks above then discharged dis-charged into the big tank down herethen through the pumps again and so on until we change it again for cleanliness And how does this water run through 1 f I i r II I c I l THE LIFTINGa VALVE BOPE b b LIFTING CABLE c VALVE PULLEY d PISTON BOD e WATER PIPE the elevators I asked as I found myself my-self standing in an alleyway of pumps and hydraulic machines which seemed to be going through a series of complicated dress parade manoeuvres all in unison for my particular bewilderment I can make that plain to you in two I minutes said the engineer with rather reckless confidence You see each elevator has its water tans at me top 01 I the building and its own hydaulic machine at the bottom and the two are connected by an eightinch iron pipe That pipe lets the water from above into L the threefoot cylinder of the hydraulic machine and this water is kept by the I pumps at a presnre of 100 pounds to the square inch Consequently whenever the water presses into the cylinder it drives this piston rod out to its full length sixteen feet with the force of some scores of tonsthe calculation is easy if 1 you remember the formula Now this c piston rod in moving pulls apart what i YOU might call the two blocks of an enormous pulley with five wheels in each b ck Here they are see And the wire rope which runs around these I pulley wheels goes over a wheel up under the roof and then down till it catches the top of the elevator car As there are ten wheels in the two pulley blocks the end of the rope with the car attached travels ten times as far as the piston rod does or tea times sixteen feet which is the distance dis-tance the elevator travels up and down I What brings the piston back and the elevator down I The Rhancnnc ot this valve where the Iron pipe joins the cylinder When the valve is thrown one way the water presses into the cylinder and up goes the elevator when the valve is thrown the other way the pressure on the piston is relieved and t the water is discharged into the tank over there through these pipe Then the I b elevator comes down by its own weight and that of the passengers The valve is R worked by the elevator boy when he pulls the cord either way and if he should forget for-get to pull the cord the valve would act automatically just us the valves in an engine do The wider the valve is opened going eithor way the faster thaear goes TJTJ to a certain point where whatever might happen even supposing the valve to bursts a separate attachment consisting consist-ing of an independent cable would stop the car by the action jwhat we call the safety governor There you have the whole thing in a nutshell o 1 And what if the wire rope which holds the car should break The elevator would stop instantly as ito it-o would also if one of the four ropesfor there are four not one should evens even-s eich The car would stop vbecause byre by-re ns of a simple device aeries of l J u 1 = I wedges would be thrown out and grip the iron frame in which the elevator slides The heavier the Joad the nard r the wedges would hold Many other things I learned about elevators in the course of my visit and finally emerged into Broadway feeling myself an authority on the subject I I have since found that this is only one of many elevator systems in use but it I gives the basic idea of most of them Ins In-s me elevators the big cylinder is visible above the floor in a vertical instead of a horizontal position with the pulley wheels scattered along at intervals on the way up as ifto give the passengers food for reflection In some again there u no water tank at the top of the building tile requisite pressure being obtained by pumping compressed air These are details de-tails whicKconcern the elevator men only and not the general public Itis a splendid splen-did achievement to have mastered the mans point of a single system One point which I found interesting is the question of speed How do these elevators ele-vators run How many miles do they cover a day What is the elevator record This mereJydepends upon the number of pulley wheels YOI1J have attached to your pistonrod With six seven or ten pairs of pulley wheels instead of five pairs the elevators just under consideration would ruaj 32 64 or 160 feet farther for each stroke of the piston than they do at present The present rate is 500 feet a minute so ten pairs of pulleys would give 1000 feet a minute Twenty pairs would give 2000 feet a minute forty pairs 4000 feet a minute and eighty pairs 8000 feet a minute min-ute or over eighty miles au hour The oretically there is no limit but as a matter I mat-ter of fact with these constant stoppages at every floor the present speed of elevators ele-vators is considered as great as will ever become advisable Already in express I elevators in Chicago in such human beehives bee-hives as the Rookery where no stop is made before the tenth or twelfth floor elevators are run at the rate of 800 feet a minute The average New York elevator may be said to carry twenty passengers many carry more some less but taking these figures and allowing 500 complete trips up and down as the daily work of an elevator ele-vator in the busy buildings then we find each of these elevators carry 10000 people daily when it runs full It is a fact that the city contains 7500 elevators at present including those in private houses ana others where the traffic is comparatively small If we ad sume however merely to dazzle the fancy that 5000 of these are in busy buildings then we find that the elevators of New York could carry up and down per day 5000 times 10000 people or not far from the entire population of the United States Again by the beautiful law of averages we find that twenty miles is a fair daily run for a New York elevator The highest single elevator is the one in the Washington monument which is worked by steam the chair being rolled upon a drum It makes in safety what it lacks in speed The largest elevator in the worldin fact there are three of a sizemay be seen at Weehauken where the passengers for the West Shore line are lilted by hy draulic power 165 feet to a trestle struc ture where they take the trains Each car will accommodate from 150 to 200 people peo-ple Immense elevators on a similar plan are being built at Glasgow for the tunnel under the Clyde I have said nothing about the safety aircushion device at the bottom of elevator ele-vator shafts which in case of accident is supposed to receive the falling car so gently that a basket of eggs would not be broken The best point about this air I cushion is that it has not seen much service ser-vice as yet the double safeguards already mentioned having proved sufficient in almost al-most every instance It is a good idea however if you can remember it to spring for the crossbeam at the top of I the car should you find tho elevator flying downward with nothing to stop it but the I vir cushion Then hang by your arms I and if the aircushion does its work well 1 and good if it does not you may get off with having your arms wrenched instead of being killed |