Within the past six or eight years, the great improvements made in the use of tin plate in the manufacture of cans, and every variety of articles for domestic use, have excited the wonder of all who have not made themselves familiar with this subject. The enormous consumption of cans for different purposes, has led to many patented improvements tending to reduce their cost, or to add to their utility and convenience. The constantly increasing price of oak timber for staves, and the difficulty of obtaining such as are suitable for the secure transportation of oils and other penetrating fluids, render the substitution of cans almost a necessity. Nature has given us an unfailing supply of iron, the basis of tin plate, and the cost of the latter, notwithstanding the large duty upon it, has become so low, that with the advantages of improved machinery, and the economy of a well organized business, packages for the transportation of oils, can be furnished at almost the same price in proportion to capacity as well-seasoned barrels. For these reasons, together with freedom from leakage, and the avoidance of danger and loss by spilling, or changing of goods from barrels or casks by the dealer or retailer, it has now become a universally acknowledged fact that it is cheaper to buy oil, spirits of turpentine, etc., in such cans, than in barrels. Among the many candidates for public favor in this line, “ Pratt's Guaranty Patent Can,” of which we give herewith an engraving, has gained an enviable reputation, and is probably as perfect a device for the purpose designed as has ever been invented. From the extended use of these cans a necessity has arisen for some simple and cheap means for overcoming the difficulty, which has been experienced in emptying cans and smdl vessels without spilling some of the contents, resulting principally from the fact that there was no vent or conduit for admission of the air to the can, while the liquid was being poured out. To remedy this difficulty, vent-nozzles or other like devices have hitherto been used with cans or vessels ; but such appliances have always been costly, and their use has been attended with inconvenience, while they require cans of special construction, and indeed, arepermanently united with and form parts of the cans. A device of this kind, however, has been recently invented and patented by Charles Pratt, 108 Fulton street, New York city, which is worthy of attention. It is simple in construction, can be easily and cheaply mads, may be readily removed from or applied to the can, and used with any can of ordinary or suitable construction, and may be manufactured and sold as a distinct article, not necessarily accompanying the can. The invention consists of a stopper, also shown in the engravings, for oil cans, or other liquid-holding vessels (for whatever use), provided with an opening or spout for tlie outflow of the liquid, in combination with a vent for the ingress of the air. The manner in which this device can be constructed and used will be readily understood by reference to the drawings. The body of the stopper, which is here represented as composed of cork (but which may be made of any other suitable material), carries a tube or spout for the outflow of the liquid, and another and smaller tube to act as a vent. The two tubes pass down through the body of the stopper and open into the interior of the vessel, the smaller, or vent-tube, being arranged upon one side of, and so as to follow the curve of the larger tube, so that when the vessel is tipped to pour the liquid, the larger tube\vill be beneath, by which arrangement the oil or fluid will flow only through its proper channel, the larger tube, or spout, leaving the smaller tube or vent free for the passage of the air. The tubes are fastened to the cork by means of metal disks, which are soldered tothe tubes at such a distance apart as to compress the body of the cork between them, the turned-up edges of the disks entering the cork and holding it tight. As already stated the device may be formed of cork or of any other suitable material capable of closing the orifice in the can , it may also be of metal and can be screwed into or upon the neck of the can. In any event, however, a detachable stopper will be obtained, in which the spout or opening for outflow is combined with a vent; and this device can be applied to any can, vessel, or receptacle for liquids, whatever its shape or size, provided that such receptacle be provided with a neck or mouth, into which the stopper can be fitted.
This article was originally published with the title "Pratt's Patent Vent Stopper" in Scientific American 21, 23, 357 (December 1869)