PREFACE.
I have been prompted to prepare this book by the frequent inquiries made regarding the details of our system of pneumatic tubes. These inquiries have come from people interested in our company, from others interested in companies that have purchased the right to use our apparatus, from people desirous of becoming interested in a pneumatic-tube business, from would-be purchasers of pneumatic tubes, and from people interested in pneumatic tubes from a scientific, engineering, or mechanical point of view. This book is not intended to be a treatise on pneumatic tubes. In the first chapter I have given a brief sketch of what has been done in the application of pneumatic tubes from the earliest records to the present time. The second chapter contains a description of the postal tubes in Philadelphia, and the third chapter describes our system in detail. Following this is a short chapter explaining the theory of pneumatic tubes, or the theory of the flow of air in long pipes, stating the more interesting facts and relations in as plain and simple a manner as possible. Mathematical formulæ have been purposely avoided.
Several plates showing the Philadelphia postal line have been kindly loaned to me by the Engineers’ Club of Philadelphia. They formerly appeared in a paper read by Mr. A. Falkenau before that club. I have also to thank the and Drill Co., the B. F. Sturtevant Co., the Wilbraham-Baker Blower Co., and J. B. Stewart for the use of electrotypes of their machines.
B. C. B.
October 6, 1896.
THE
Batcheller Pneumatic Tube System.
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CHAPTER I.
A BRIEF HISTORICAL SKETCH.
Early Records.
—The earliest reference to pneumatic transmission of which we find any record is a paper presented to the Royal Society of London, by Denis Papin, in the year 1667, entitled “Double Pneumatic Pump.” His plan was to exhaust the air from a long metal tube by two large cylinders. The tube was to contain a piston, to which a carriage was attached by means of a cord. The “American Cyclopædia” goes on to say, “More than a century elapsed before any further effort in this direction was made. Paucbrouke’s ‘Dictionnaire Encyclopédique des Amusements des Sciences’ (1792) gives a description of a machine by M. Van Estin, by means of which a hollow ball holding a small package was propelled by a blast of air through a tube several hundred feet in length, and having many curves. This plan seems, however, to have been more an amusement than an attempt to introduce an industrial scheme. With more regard to practical results, Medhurst, an engineer of London, published a pamphlet on the subject in 1810. He proposed to move small carriages on rails in air-tight tubes or tunnels, by compressed air behind, or by creating a partial vacuum in front. In 1812 he published another pamphlet; but the plan was not put into successful operation, principally from insufficient means of exhaustion. About 1832 he proposed to connect the carriage inside such a tube with a passenger carriage running on the top of the tube; and, although the latter project has never been commercially successful, it was the first to be practically attempted. More than a score of patents were taken out on the Continent and in England and America, none of which met with any practical success. Returning to the original idea of Denis Papin, inventors attempted to accomplish pneumatic transmission by moving the load inside the tube, and in course of time achieved success. In France MM. Jarroux and Taisseau presented a project for atmospheric telegraphy before the Academy of Sciences, and they were succeeded in the same direction by MM. Brochet and Ardor.”