After I've got new task from the Boss which is I have to do safety patrol, that means I have to control the safety of the employee when they work such as erection, brazing, welding, chamfering, etc, and that's make my times reduced to take a post for this Piping & Fabrication. But that's doesn't matter because I will keep posting and today we talk about Joining Ductile or Cast Iron Pipe and here we go.
Bell-and-Spigot Joint
This joint for underground cast-iron pipe was developed as long ago as 1785. Standard dimensions are shown in Table A2.22. The joint may be made up with lead and oakum, sulfur compounds, or cement. Lead and oakum constitute the prevailing joint sealer for sanitary systems. Belland spigot joints are usually reserved for sanitary sewer systems. These joints are not used in ductile iron pipe.
Mechanical (Gland-Type) Joint
This modification of the bell-and-spigot joints, as designated in Federal Specification WW-P-421 and ANSI/AWWA C111/A21.11, is illustrated in Table A2.23. This joint is commonly used for low and intermediate-pressure gas distribution systems, particularly those conveying natural gas or dry manufactured gas. Mechanical joints are also used for water lines, sewage, and process piping. In the mechanical (gland-type) joint shown in Fig. A2.30, the lead and oakum of the conventional bell-and-spigot joint are supplanted by a stuffing box in which a rubber or composition packing ring, with or without a metal or canvas tip or canvas backing, is compressed by a ductile cast-iron follower ring drawn up with bolts. In addition to making an inherently tight joint even under considerable pressure, this arrangement has the advantage of permitting relatively large lateral deflections (3 1/2* to 7*), as well as longitudinal expansion or contraction. For more details, refer to AWWA C600, Standard for Installation of Ductile-Iron Water Mains and Their Appurtenances.
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| FIGURE A2.30 Mechanical (gland-type) joint |
Tyton Joint
The Tyton joint is designed to contain an elongated grooved gasket. The inside contour of the socket bell provides a seat for the circular rubber in a modified bulbshaped gasket. An internal ridge in the socket fits into the groove of the gasket.
