The local lines, serving to collect oil from the wells, and deliver it into the storage tanks, are usually of small pipe, ranging from two to four inches in diameter, and are often laid directly on the surface of the ground. The trunk lines are usually underground, and consist of a special wrought-iron pipe six to twelve inches in diameter. Relay pumping stations are placed along the lines at intervals varying with the character of the country traversed. For example, on the southern pipe line from Morgantown, W. Va., to Baltimore, the first part of the route is mountainous, which means lifting the oil over many elevations. There the pumping stations are about thirty miles apart. At the eastern end, where the country is flat and practically no lifting is necessary, the interval be tween stations is twice as great.
The pumping station is the gateway through which the crude oil finds its way from the well out to the world. Each station is equipped with two or more tanks, like giant cheeseboxes, holding from 30,000 to 50,000 barrels; one tank receives oil while it is being pumped out of the other, so that the stream of oil through the pipes need never cease. Powerful triple-expansion pumps capable of driving 35,000 barrels of oil a day easily overcome the friction of the heavy oil as it flows through the pipe. A modern station, including the tanks, costs not less than $75,000, and a trunk line of eight-inch pipe costs about $5,000 to $6,000 a mile, hence extensive pipe-line transportation is clearly a business for large capital only.
The difficulties of transporting oil by the mod ern pipe line are comparatively few, except in the case of some especially heavy oils, such as those found in California. The chief trouble encoun tered in the case of ordinary petroleum is the gradual choking of the pipes with accumulations of solid deposits and impurities from the oil. The cleaning of the pipes, however, is done quite easily by an ingenious device known as the "go devil." It is essentially a spindle so constructed that the current of oil forces it through the pipe, and at the same time causes it to rotate rapidly, a system of sharp blades scraping the sides of the pipe clean as it is sent whirling along from station to station.
The introduction and extension of pipe lines revolutionized, to a large degree, the whole aspect of the industry. The most important of these changes was in shifting the base of refining opera tions. For nearly twenty years after the industry began, the crude oil was refined mainly in the neighborhood of the wells, and only the valuable products were shipped any great distance. Out side the oil regions, the refineries were confined largely to the leading commercial centers, as New York, Philadelphia, Baltimore, Cleveland, and Pittsburg, where good railroad facilities combined important local markets with easy access to out side districts.
The completion of trunk lines, together with the rapidly growing export trade, allowed the seaport refineries to expand rapidly. Refining establish ments in the remote oil regions, were placed at a great disadvantage, or could not compete at all. Plant after plant was absorbed by the Standard interests, operations were discontinued, and many of the refineries sooner or later were destroyed by fire. Only a comparatively few smaller concerns were left when the transformation ended in the early eighties. From that time on, an ever-increas ing proportion of the refining business has been concentrated in the extensive plants located where the two chief conditions of profitable operation are found—namely, large demands for local consump tion and ease of shipment elsewhere.
Pipe lines have never been used to any impor tant extent for the handling of refined oils, mainly because that method of transportation to any great distance is more economical than shipment by rail only when enormous quantities are to be carried daily, as in supplying big refineries with the crude oil from the wells. For this reason it is preferable to pipe the crude to the large consuming centers, refine there, and then distribute the products by other means.
Next to its influence on the location of the refin ing industry, the most important effect of the mod ern pipe-line system has been on the producers' side in the storage of oil. The early operators had to store their own oil as it came from the well, usu ally in wooden tanks holding a few hundred to a thousand gallons. Fires were frequent, and, though making grand spectacles to witness, the an nual losses frequently mounted up into the hun dreds of thousands of barrels. Hardly a thunder storm passed over the oil regions without leaving in its path one or more flaming tanks, and general conflagrations were not infrequent. Now the pro ducer pumps from his well to a receiving tank and sells direct from that tank, as fast as it is filled, to the pipe-line company, which usually means to the Standard Oil. The oil in the tank is meas ured, the valves connecting with the trunk pipe lines are opened, and the producer receives a voucher stating the quantity of oil taken. The oil so disposed of is then just as good as a bank ac count, so-called "pipe-line certificates" being is sued against it in much the same way as a bank depositor may check out his account.