The line-pipe is laid between the stations in the ordinary manner, excepting that great care is exercised in perfecting the joints. No expansion joints or other special appliances of like nature are used on the line as far as we can learn; the variations in temperature being compensated for, in exposed locations, by laying the pipe in long horizontal curves. The usual depth below the surface is about 3 feet, though in some portions of the route the pipe lies for miles exposed directly upon the surface. As the oil pumped is crude oil, and this as it comes from the wells carries with it a considerable proportion of brine, freezing in the pipes is not to be apprehended. The oil, however, does thicken in very cold weather, and the temperature has a considerable influence on the delivery.
A very ingenious patented device is used for cleaning out the pipes, and by it the delivery is said to have been increased in certain localities 50 per cent. This is a stem about 2½ feet long, having at its front end a diaphragm made of wings which can fold on each other, and thus enable it to pass an obstruction it cannot remove; this machine carries a set of steel scrapers, somewhat like those used in cleaning boilers. The device is put into the pipe, and propelled by the pressure transmitted from the pumps from one station to another; relays of men follow the scraper by the noise it makes as it goes through the pipe, one party taking up the pursuit as the other is exhausted. They must never let it get out of their hearing, for if it stops unnoticed, its location can only again be established by cutting the pipe.
The pumping stations are substantial structures of brick, roofed with iron. The boiler house is removed some distance from the engine house for greater safety from fire; the building, about 40 by 50 feet, contains from six to seven tubular boilers, each 5 by 14 feet, and containing 80 three-inch tubes. The pump house is a similar brick structure about 40 by 60 feet, and contains the battery of pumping engines to be described later. At each station are two iron tanks, 90 feet in diameter and 30 feet high; into these tanks the oil is delivered from the preceding station, and from them the oil is pumped into the tanks at the next station beyond. The pipe-system at each station is simple, and by means of the "loop-lines" before mentioned the oil can be pumped directly around any station if occasion would require it.
The pumps used on all these lines are the Worthington compound, condensing, pressure pumping engines. The general characteristics of these pumps are, independent plungers with exterior packing, valve-boxes subdivided into separate small chambers capable of resisting very heavy strains, and leather-faced metallic valves with low lift and large surfaces. These engines vary in power from 200 to 800 horse-power, according to duty required. They are in continuous use, day and night, and are required to deliver about 15,000 barrels of crude oil per 24 hours, under a pressure equivalent to an elevation of 3,500 feet.
We have lately examined the latest pumping engine plant, and the largest yet built for this service, by the firm of H.R. Worthington; it is to be used at the Osborne Hollow Pumping Station. As patents are yet pending on certain new features in this engine, we must defer a full description of it for a later issue of our journal.
The Pennsylvania line has a single 6-inch pipe 280 miles long, with six pumping stations as shown in the map, and groups of shorter lines, with a loop extending from the main line to Milton, Pa., a shipping point for loading on cars. At Millway, Pa., a 5-inch pipe leaves the Pennsylvania line and runs to Baltimore, a distance of 70 miles, and is operated from the first named station alone, there being no intermediate pumping station. The Cleveland pipe, 100 miles long, is 5 inches in diameter, and has upon it four pumping stations; it carries oil to the very extensive refineries of the company at the terminal on Lake Erie. The Buffalo line is 4 inches in diameter and 70 miles long; it has a pumping station at Four-Mile and at Ashford (omitted on the map). The Pittsburg line is 4 inches in diameter and 60 miles long; it has pumping stations at Carbon Center and at Freeport.
[Footnote 1: Millway is about 400 feet above tide-water at Baltimore, but the line passes over a very undulating country in its passage to the last named point. We regret that we have no profile on this 70 mile line operated by a single pumping plant.--Ed. Engineering News.]
A very necessary and remarkably complete adjunct to the numerous pipe lines of this company is an independent telegraph system extending to every point on its widely diverging lines. The storage capacity of the National Transit Co.'s system is placed at 1,500,000 barrels, and this tankage is being constantly increased to meet the demands of the producers.
[Footnote 1: As showing the extent of the sea-coast transportation of petroleum, we should mention that the statistics for 1884 show a total of crude equivalent exported from the United States in that year, equaling 16,661,086 barrels, of 51 gallons each. This is a daily average of 42,780 barrels.]
The company is officially organized as follows: C.A. Griscom, President; Benjamin Brewster, Vice President; John Bushnell, Secretary; Daniel O'Day, General Manager; J.H. Snow, General Superintendent. Mr. Snow was the practical constructor of the entire system, and the general perfection of the work is mainly due to his personal experience, energy, and careful supervision. His engineering assistants were Theodore M. Towe and C.J. Hepburn on the New York line and J.B. Barbour on the Pennsylvania lines.
The enterprise has been so far a great engineering success, and the oil delivery is stated on good authority to be within 2 per cent. of the theoretical capacity of the pipes. From a commercial standpoint, the ultimate future of the undertaking will be determined by the lasting qualities of wrought iron pipe buried in the ground and subjected to enormous strain; time alone can determine this question.
In preparing this article we are indebted for information to the firm of H.R. Worthington, to General Manager O'Day, of the National Transit Co., to the editor of the Derrick of Oil City, Pa., and to numerous engineering friends.--Engineering News.