MORE ABOUT BIG STREAMS.
WHAT we have had to say of late regarding large streams for fire purposes has evidently set people to thinking, and we have had numerous calls from persons who desired to talk upon the subject. We have also received several communications discussing the matter, and to show the divergence of opinion we quote two of them, as follows:
[To THE EDITOR OF THE JOURNAL.]
NEW YORK, June 11, 1881.
Your nozzle won’t do; you will set the water a boiling at that point, and get nothing but a ragged stream. Sorry you published that sketch as you will get picked up on it. J. S.
[To THE EDITOR OK THE JOURNAL.]
WARWICK, N. Y., June n, 1881.
You are on the right line, although you claim not to be scientific. Why, my dear sir, it is the highest science. I have been experimenting for several years with nozzles and streams and proved long ago that a short nozzle would beat any other. Your illustration on page 506 of THE JOURNAL is the true principle so far as the nozzle goes, except that you should have said that the length of nozzle tube should be equal to the diameter of the orifice, and the inner and outer lipsor corners should be champhered ofl or rounded just a trifle, say 1-16 of an inch. The discharge tube should be perfectly straight, t have been hoping to be ready to introduce a new invention of my own for a long time, but my duties as manager of the Fabric Fire Hose Company’s factory have absorbed all my time. I will say, however, that I have no claim on such a nozzle and recommend its adoption by all fire Companies. Any work on hydraulics will explain the science of just such an orifice for the discharge ol water. J. E. GILLESPIE.
“The proof of the pudding is in the eating,” and, notwithstanding what “ J. S.” says, we believe the nozzle we propose to be better than one that has a taper to it. Since our atticle of last week we have had an interview with Mr. Hildreth, Secretary of the Holly Water-Works Company, who agrees perfectly with our idea, and, as he has had a large experience in putting in Water-works, his opinion is of great value. We have alluded several times to the Holly Works at Rochester, N. Y„ as being the most complete of any in the country. Mr. Hildreth informs us that when these works were finished the trial test was very exacting. One test was throwing a 3-inch stream and another a 5-inch stream. The tormer was projected over 300 ieet vertically, and over 400 feet horizontally; the 5-inch stream was only played 3 minutes, as the neighboring cellars were being filled with water, and they were obliged to shut down, but during those 3 minutes the stream was thrown 260 feet high. We have seen a photograph of that column of water which shows it to have been like a great water spout, rising high above the surrounding buildings, one of which was the tallest in the city. This immense volume was obtained in precisely the manner we have been advocating, viz. : by bringing a great body of water as near as possible to the point of discharge, and doing away with a play-pipe. A standpipe 5 inches in diameter was located directly upon the large street main, and the largest stream was thrown through the open pipe ; then a cap was fitted on the opening, having in the centre a 3-inch orifice ; a 3-inch stream was thrown through this orifice without either nozzle or playpipe ! To reduce the size of the stream, a short nozzle was fitted into the orifice in the cap. This is precisely what we have been contending for—a large body of water at the point of discharge, and a short nozzle with parallel sides.
Manufacturers of hose will hail with delight the day when play-pipes will be discarded, for, as shown at the trial two weeks ago, the moment a playpipe is attached, the pressure on the hose is largely increased. By doing away with the pipe and playing through a short nozzle, with free waterway, the hose will be subjected to very much less strainThat play-pipes are an obstruction has long been recognized. In the old volunteer days, play-pipes were sometimes made as much as twelve feet long, having a gradual taper from the butt to the outlet; now play-pipes for fire duty are seldom made more than three feet long, showing that practical men have recognized that they were an obstruction to the delivery of the stream. They have, however, maintained that a tapering play-pipe of some kind was necessary to “ form ” the stream in a compact shape before discharging it. As a matter of fact, the play-pipe has served to disintegrate the water, churning it up into a foam almost, so that when it passed the nozzle it sprayed badly, the greater part of it passing but a short distance. In trials of Engines for distance throwing, it is usual to measure the most remote drop that falls, and call that the distance thrown, when, as a matter of fact, the stream that would have been the least service in extinguishing fire fell fifty feet or more short of that point. We have seen at these trials, sheets ot white paper laid down at the point which it was expected the drops would fall, and the most distant drop marked on the paper and the measurement taken from that. It is by this means that records of Steamers throwing such long distances have been made. What an absurdity to call such precarious drops of water a fire stream. The great beauty of the stream thrown at the recent experiments in this city, when the nozzle was inserted in the butt of the hose, was that at 260 feet the water fell in a perfect torrent, while spurts were projected 270 feet and more. The stream thrown through the play-pipe, under the same pressure at the pumps, fell more than 20 feet short, although an occasional drop reached 270 feet. But for fite extinguishment, the sti earns at 260 feet were as a violent thunder shower to a sprinkling pot.
It has been a mooted question recently whether the Engines now in service are of sufficient capacity to cope with the many tall buildings that are now being erected in the large cities, and filled with the most combustible material. We believe they are if properly handled and proper appliances are brought into requisition. The recent introduction of Siamese connections—by means of which two, three or four lines of hose can be brought together to deliver a single stream—is a long step in advance towards getting large and powerful streams. With a single Steamer playing through two lines of 2 -inch hose to a Siamese, and delivering one stream through a 3X or 4-inch hose, far better results are obtained than if the Steamer played two streams without the Siamese. Two lines from each of two Steamers can be brought together in a similar manner, and a stream of great size and power can be obtained. In fact, it is only by such combination of power that streams can be projected to the roofs of hundreds of buildings in this city. No doubt engines of greater capacity could be used to good advantage, but what is gained in power is more than lost in the time consumed in transporting them to the scene of a fire. Two light Engines, that can be easily drawn by two horses, are, unquestionably, far more serviceable for ordinary duty than one that is more powerful but cumbersome and unwieldy. The secret of success in fire extinguishment is to catch the fires in their incipiency and put them out with small streams. For this, large, heavy Engines are not available. But when a fire gets well under headway, it becomes necessary to drown it Vith’largejstreams of water, thrown with great velocity. We incline to the belief that, for that purpose, it is more economical to combine the power of two Engines, by siamesing them, than to cumber a Department with heavy, powerful Engines that cannot be so quickly handled. But a great portion of the power exerted by our Engines is consumed in overcoming the friction caused by small hose. At the recent test it was demonstrated that in a 200-foot line of 2j£-inch hose the resistance upon the pump was 65 pounds, the butt of the hose being left open and no pressure indicated at the opening. Hose four inches in diameter should be introduced in Fire Departments as speedily as possible to secure the best work of the apparatus, because the loss by friction will be so much less than in the 2^-inch hose now in general use. In regard to the friction loss, Chief Leshure, of Springfield, Mass., in his book entitled “ Fire Streams,” says : “ When delivering the same number of gallons per minute, the friction loss in two pipes (or hose) of equal lengths, the diameter of one of which is twice that of the other, the loss in the larger will be onethirtieth of that in the smaller, or the loss in the smaller will be 30 times that in the larger.” Why, then, should the power of our Engines, that is needed for projecting streams of water, be consumed in overcoming friction in small hose when larger hose is better for every purpose, and can be made just as light and available as the small hose? We venture to say that if 4-inch hose were used instead of 2inch, and playpipes totally discarded, our Engines would show fifty per cent better fire extinguishing capacity than they now do, that is admitting that large streams projected with great velocity are desirable. There is much to be learned yet in reference to obtaining fire streams economically, and the more discussion and experiments brought to bear on the subject, the sooner shall we arrive at satisfactory re ults.