The amount of lead used for calking our flanged joint is about one-eighth that required for the ordinary joint. The lead gasket for four-inch pipes weighs half a pound, and for two-inch pipe one-fourth of a pound, while the rule for calking ordinary joints is to use one pound of lead for every inch in the diameter of the pipe. We also save the fuel, oakum, etc., used in making ordinary joints, and avoid the danger of fire from lead melting in the house.
Fig. 525 shows the lead packing ring in perspective, and Fig. 526 shows its star-shaped section in actual size for plumbers' pipes. It is crushed to less than half its thickness into every pore and crevice of the iron by the pressure of the two half-inch bolts screwed up easily by a man of ordinary strength with the fourteen-inch ratchet wrenches, until the spigot on one pipe comes to a bearing on the flange surface of the other, Fig. 523. In this way the workman is informed when the joint is made up, and the lead packing thus protected cannot be affected by the expansion or contraction of the pipes. The expansion of the two flanges being the same, no injury can be done to the joint by hot water or steam, as was demonstrated by repeated tests.
The strong bolts prevent leakage by sagging or horizontal tension of the pipes up to the point of the rupture of the iron, while the ordinary bell-and-spigot joint depends for its resistance to such a strain only on the friction of the lead calking against the sides of the iron.
Fig. 5 35.
The flush flanges enable any piece of the piping to be taken out for alterations without breaking it, and the opportunity and temptation for the use of sand, paper, putty or other fraudulent packing is prevented, since all the packing used is directly visible from the outside when set in place.
Branches and fittings of various kinds similar to those used in wrought iron screwed piping enable any change of direction to be obtained with entire facility, as is made clear by the drawings. All pipe cutting, which is both very difficult, expensive and dangerous to the pipe, is avoided, because a sufficient number of different short lengths and bends or angles are supplied to meet every requirement, the jointing being so easy and quick that a variety of lengths becomes worth while and entails no practical difficulty.
Being cast in short lengths, the pipes may be made of more uniform thickness, and as the calking requires no hammering, even porcelain or glass-lined pipe might be used with safety if desired.
The simple manner in which lead and iron pipes are connected with this joint is shown in Figs. 533 and 534.
Fig. 535 shows without further explanation how the pipes may be capped for the hydraulic or other test, and Fig. 532 has a turned brass expansion or slide joint with a fibrous packing inserted.
To test the resistance of this joint to alterations of steam and cold water pressure before using these pipes in practical building, I had several lengths of four-inch piping connected together and closed up at the ends, and coupled the whole with a steam boiler, the pressure gauge indicating about 30 pounds of steam pressure. The steam was left on until the pipe-flanges and bolts had all become thoroughly heated through. The coupling was then immediately transferred to the cold water supply from the city main, and after the steam had been let out the cold water was suddenly turned on until the piping was filled. As the experiments were performed in midwinter, the tests were as severe as possible. The cold water was then poured out and steam again immediately applied. This alternating application of steam and cold water was repeated in the tests a dozen times successively on the same joints. During the entire process no sign of leak, either of steam or water, was obtained, and no creeping or alteration of the gasket occurred.
It is well known that no bell-and-spigot joint will stand such a test, even after the most careful calking, as indeed is evidenced by the plumbing laws which prohibit the discharge of exhaust steam into plumbing drains.
This joint has also the advantage of causing no obstruction to the waterway, and of leaving no appreciable space or pocket for deposit.
But flange joints are not flexible, and are therefore incapable of protecting the pipe line against the effects of street settlement, expansion and contraction and other adverse influences already referred to as affecting water and gas mains. In plumbing work a rigid jointing is always liable to cause the fracture of the fixture connections, especially when they are made of earthenware, in all cases of shrinkage or settlement of the building and of expansion and contraction of the pipe lines.
The Durham system of wrought iron screw jointed piping attempts to partially overcome this difficulty by supporting some of the fixtures directly upon the rigid branches of the main pipe lines independently of the floors. But this only transfers the strain from one part of the fixture to another, because even if, by this means, the fixture itself could be compelled to follow the movement of the main piping, or to remain with it when the walls settle or the floor beams shrink, the flushing apparatus of the fixture cannot be similarly connected, and therefore the rupturing strain must still remain, and the device becomes practically inefficient. The rigid system of jointing is responsible for most annoying and vastly expensive losses by fracture and leakage generally misunderstood or unaccounted for by the owner.
A realization of this fact will be most effectively impressed upon an observant owner of any high building in which hot and cold water are alternately used in large quantities, as in hotels.
Investment in such a building presented the writer with such an opportunity for expensive experience along this line.
Wrought iron piping was here used for the soil pipes, the building having been planned and erected by the writer before his efforts to obtain a permanently reliable joint had been made. The great need of it had not then been made so painfully clear to him as to seem to justify a very considerable expenditure of time and money in "experimentation."
The final result has been the development of a flexible joint which has withstood for several years very severe tests, which have been continued up to the present time.
One of the tests has consisted in placing one of the joints under a water pressure varying from 45 to 50 pounds to the square inch off and on for three years, moving the pipes at the joint from time to time, sometimes while the pressure was off and sometimes when it was on, without producing the slightest signs of leakage.
The last tests were made within the present month (Nov. 1910), and having proved themselves successful, the writer feels himself now justified in publishing here, for the first time, a description of this joint, and also justified in naming it