The Brooklyn Pumping Engines of 1860.
There is an important distinction between the upper and lower faces of any pump piston in action. While the load on the upper side is the entire mechanical water lift, and depends on the relative level of the piston, below the piston the atmosphere makes the lift, and the resistance is a simple question of vacuum formed; and this is to an important extent independent ot the relative height of the piston above the water, and shows the necessity of engine inertia to prevent too rapid a start.
The law of vis vivo, by which the resistances are reduced instead of increased in the water column in motion as its lift increases, is shown in the annexed cards (Figs. 20, 21 and 22).
In the first card, the conditions of free delivery to the plunger barrel are very favorable, since there is a water head of 3.5 feet, and very large valves, with a short passage from the forebay; yet from too rapid motion or other cause, to start the column and maintain its flow, the indicator opeiis with a vacuum of over 3 lbs.; at the first foot, 6.25 lbs.—average, 4.25 lbs.; showing at the first foot a vacuum equal 14.37 feet lift under an actual load of 2 feet, and at the end of the stroke the vacuum is 2 lbs. or 4.6 feet, when the actual lift is 6 feet above the well. The pump might have been about 15 feet higher with so much less water load.
In the second card (also a plunger, single acting) it is evident, as the velocity water stroke of the first engine shows, that there is a lack of counterweight. Here the vacuum is 8 lbs., or 18.4 feet lift, against 8.15 actual; at the first foot, 24.15 feet against 9.15; at the end. 4 lbs, or 9.2 feet, where the actual lift is 19.07 as the vis viva effect of the column; and the mean vacuum is 9.34 lbs., or 21.48 feet, against 13.61 actual, another waste of power.
In the third card the upper pump dees its work about 1.39 lb. per square inch less than the lower, which starts with a bucket load of about 3 feet. The lift is 10.58 feet, and the vacuum 17.25 at the start; at one foot pull, 20.7 feet; lift, 11.58; final null, 6 lbs., or 13.8 feet, with an actual lift of 20.45, 8 9 lbs; mean lift, 15.51 feet; vacuum, 17.52.
This engine was doing nearly five limes the work of the second, and the economy of pump position is clearly shown, involving a gain peculiar to this form of engine.
The Hartford and Cambridge pump cards show similar action (Figs. 23, 24, 25).
In these pump cards the same law of vis viva developed by air pressure is proved in direct mass pressure or steam.
In addition to cards given, the following have certain important bearings;
The Belleville counterweight (standpipe), without air-chamber relief, opens the card with a load of 66.5 lbs., or 153 feet lift, against an actual of 139.76; the surplus work then reduces the load to a final resistance of about 60.5 lbs., or 139 feet, the actual being 150.68.
With all its care in design and reciprocal pump relief, but with 4 pumps acting on the same 12-inch miin, the Hartford pump opens with 61 lbs., or 140.5 feet lift, against an actual of in.76, or 48.6 lbs.; the wave reduces the load to 49 lbs. at the close, or 112.7 feet. against an actual ol 110.43.
The Cambridge horizontal pump, opening with a partly unfilled chamber, and without much weight, strikes solid water with a blow of 41 lbs., which includes some spring vibration, against 27.8 actual, and ends with 32.
In these, and abundant other cards, the same law of wave generation, acceleration and retardation is demonstrated in full confirmation of theory. What is true of the cylinder card is true also of the pump card under a fixed law.
In further demonstration of the modifying effects of counterweight and air cushion on the pump wave, the following average card, taken in the capacity (Brooklyn) test, with about lo^ strokes per minute is given (Fig. 26). While the same want of weight is shown in the initial blow, the rapid reduction of reaction is also shown, and the return control of the air chamber (which absorbs part of the intial work) tends to equalize the wave motion, the practical reduction of final resistance being about 4}⅛ pounds; the air chamber in this case acting on the main, in its turn, to propel the wave from the power stored in it at the beginning of the stroke.
Engine No. 2, after the acceptance of No. 1, was built substantially a duplicate, except that the cylinder bore was 85 inches the capacity of the counterweight chests was enlarged (though not properly used), the valves of each annular pump barrel were changed to 8 double beat foot valves, instead of one upper 54-inch (without any special gain), with some minor changes. It was tried May 21, 1861, and tested February, 1S62; duty reported being 619.037 foot-pounds.
My resignation being made in i860, the engine was not built under my charge, and like No. 1, it never was properly loaded, being worked with low steam and a throttle.
It has been stated at various times that these engines were patented by Mr. Wright. The annular pump barrels were patented by him in 1859; •he diaphragm and some parts of the valve motion were his inventions; but the engine itself, as a combination of counterweighted, double acting pumps, with double beat valves on the rods, was not his improvement, and not patented.
Prospect Hill engine was built with a fly wheel, with two lifting pumps worked from the beam; 4.5 feet cylinder by 34 inches; pumps. 41 inches by 20; boiler, double return drop flue, 18 feet by 6 feet beam. It takes its supply from the 36inch city main, at the corner of Underhill avenue and Warren street; engine room floor level, 119.5 above tide; reservoir flow line, 197 feet above; (ceding main at pumps, about 106 feet.
BROOKLYN PUMP MAIN; VELOCITY CARDS.
The action of the pumps under trial was defective; with 50 jiounds steam and one-fourth to one-fifth cut off. the duty was limited to 500,000 foot-pounds. Mr. Wright, therefore, put in a new set. with easy entrance and delivery lines, with a large air chamber on the supply, embarrassed by surplus pressure. This brought the engine up in duty, so that under test of May, 1862, it made 649,577 foot-pound* as reported, “parallel” coal estimates being used on 93 hours run.
Engine Experiments.—During the winter of 1857-58, trials were made of the Belleville, Hartford and Cambridge engines. The results are collated in the following table. Messrs. Worthen. Copeland, Graff and Morris were in charge :
PUMPING ENGINE TESTS.
Annual Operation—The engine house anti its appurtenances, under the original contract provided for four engines, each of not less than 15,000,000 per day. The average consumption of 1889 was 52.9l.t38; the maximum, December, 55,112,699 gallons. With four superb engines working side by side, two of which could easily have been enlarged to lift 20,000,000 each, this engine bouse would have had no parallel; but the provisions of the original plan have been neglected. In the main room there arc now three engines; In a side room cxcrcscnce, built on the front, there are four horizontal “ Davidson ” engines 10 do the work of one ; and in a very costly engine house on the aqueduct, several hundred feet south, two vertical compound ” Worthingtons” are being completed. Engines Nos. 1 and 3, under the charge of a man who believed in crank cemres and throttling, and cared little for duty, did their work quietly and regularly, with remarkably light repair accounts. In 1866 No. 1 ran 3824 hours : engine repairs, $160.22 ; No. 3, 3066 hours; repairs, $171.84.
In 1866 Brooklyn began an extravagant system of water expenditures in various directions, under which, during 30 years’ supply, with a revenue of $26,645,902, the outlay has been for operation and maintenance, $9,543,000; interest, $16,698,000; original construction, $5,440,000; extensions, about $11,620,(xx>, or about $43,301,000.
In 1866 a full coat of ashes for the boilers was replaced by an expensive felt cover. In 1867 the 15-inch beam pin was enlarged to 20, and a new pump head made for No. 1. In 1868 an 80 inch cylinder was ordered as a substitute for No, j, 90 inch, and a new set of pumps at $27,000. In 1870 its altera, tiotr to a crank engine was decided. In 1871 three new boilers were set, though the other three were in use in 1885.
Of No. 2, the report for 1873 says : “ With the exception of new hrasses to the beam pillow blocks, and new valves to the pumps, no repairs sre anticipated on this engine,” In 1881 No, 2 ran 7420 hours ; in 1SS6, 7198 ; 1889, 8149. A continuous service of 30 years is shown by this engine of t86t.
These engines cost $138,000; No. 3, of 1869, $129750; No. 4, 1883, with building and main, $127,398 ; net, $70,000; No. 5, 1888, 2 engines, 10,000,000 gallons each. $190,471 ; house very expensive.
No. 3, as tested, had 178.43 feet lift (No. 1, 170 feet), 7# per cent loss of action (No, I, 169); could not be continuously run; credited with 683,872 ft. lbs.; duty ot 1874 590,876; repair bill, 1872. $57
No. 4. lift, 179.21 feet ; duty, by capacity of pump, 657,561 ft. lbs.; 1886, 550,988.__
THE STORY OF THE Obelisk.—At Heliopolis was the Temple of the Sun. and the schools which Herodotus visited because the teachers are considered the most accomplished men in Egypt,” When Strabo came hither, 4 years later, he saw the house which Plato had occupied ; Moses here learned ‘all the wisdom of the Egyptians.” Papyri describes Heliopolis as “ full of obelisks.” Two of these columns were carried to Alexandria 1937 years ago, and set up before the Temple of Cxsar. According to one authority, this temple was built by Cleopatra ; in any case, the two obelisks acquired the name of Cleopatra’s Needles; and though the temple itself in time disappeared, they remained, where they had been placed—one erect, one prostrate—until in recent years one was given to London and the other to New York. One recites all this in a breath in order to bring up, if possible, the associations which rush confusedly through the mind as one stands beside this red granite column rising alone in the green fields of Heliopolis. No mylh itself, it was erected in days which are to us mythical—days which are the jumping oft place of our human history ; yet they were not savages who polished this granite, who sculptured this inscription; ages of civilization of a certain sort must have preceded them. Beginning with the Central park, we force our minds backward in an endeavor to make these dates” real. “Homer was a modern compared with the designers of this pillar,” we say to ourselves. The Myceme relics were articles de Paris of centuries and centuries later. But repeating “the words (and even rolling the r’s) are useless efforts ; the imagination will not rise ; it is crushed into stupidity by such a vista of years. As reaction, perhaps as revenge, we flee to geology and Darwin; here, at least, one can take breath.