The Bell And Spigot Joint 499

Fig. 457.

Fig. 4 58.

Fig. 4 58.

The Bell And Spigot Joint 501

Fig. 459.

Fig . 460.

Fig-. 460.

The Bell And Spigot Joint 503

Fig. 461.

Machine Turned Bell and Spigot Joint with Lugs and Bolts.

This joint (Fig. 462) is for cast iron pipe, and has a tapered opening in the hub end and a corresponding tapered spigot on the opposite end, but slightly larger in diameter so that after it enters a hub, power is required to draw them together, and this power is applied by means of bolts until the beveled surfaces have been forced into positive contact. To prevent corrosion some anti-rust mixture, such as plumbago or red lead, is specified to be smeared over the machined surfaces of the joint immediately before putting together. This joint is quickly set up and requires no lead melting. It is claimed to be tight under light or heavy pressure, and even to admit of some slight play at the joint. It is called the "Universal" joint, and is made by the Central Foundry Co. of N. Y.

It is a little difficult to see how any flexibility is to be obtained with this joint under pressure without the use of some form of soft packing which when the spigot end of a pipe is slightly rotated in the hub end might be forced by the internal pressure of the liquid or gas they convey into the cavity opened by the rotation. But this the makers do not use. Nor is it clear to one who has not had experience with this new joint, how a longitudinal contraction of the pipes can take place under change of temperature without opening up the joint slightly and allowing of leakage under pressure. The manufacturers make very strong claims for it in this respect and if they prove to be justified the "Universal" joint cannot be too highly praised. It remains to be ascertained what the effect of age in corroding the joint or hardening the anti-rust mixture will be in the matter of leakage under shocks or bending strains.

Fig . 462.

Fig-. 462.

The joint seems to be, however, immeasurably superior to a lead caulked bell and spigot joint, and shares with the threaded joint in immunity from injurious effects of electrolysis.

Fig. 462a is another machine turned joint forming a ball and socket joint by the use of which pipes can be laid at an angle of several degrees out of alignment either way.

Fig. 462 a.

Fig. 462-a.

But once made up the joint is rigid. Nevertheless it would seem to be possible to set this ball and socket joint in such a manner as to secure a certain degree of rotary flexibility without leakage, but longitudinal strains could not be provided for in it. The tunnel and ground surfaces could be coated with graphite or other anti-rust lubricating compound, and the outer space, shown in solid black in the drawing, filled with melted lead. The lead would prevent the pipes from being drawn apart under mild strains, and flexibility could for a time be attained.

The joint is intended, however, to be used as a rigid rust joint, with the outer lead ring for a key to prevent separation. This joint seems to the writer to be far superior to any ordinary lead caulked bell and spigot joint. When the space between the metal to be joined is small so that the ends of the pipes are nearly or quite in contact a rust joint has its best chance for success. Such a joint however is objected to by many plumbers, says Bayles, because it becomes so rigid that it cannot be taken apart again without destroying it.

Fig. 462b.

Fig. 462b.

Fig. 4626 is a turned rust joint. It is made by turning the inside of the hub and the outside of the spigot to fit each other.

It has the disadvantages of all rust joints already referred to.