AWWA C515 MJ Gate Valves | AWWA C153 & C111

SJZ Metalsin supplies AWWA C515 MJ gate valves with non-rising stem (NRS) and resilient seated design for water supply service. These valves are furnished with reduced-wall body and made from cast ductile iron. The term “MJ” refers to that the valve shall be provided with mechanical joint ends in accordance with AWWA C153 and AWWA C111.

Figure-1: Product photo of AWWA C515 mechanical joint (MJ) gate valves: handwheel operated & stem cap operated. Design pressure rating: 300 psi.

The mechanical joint end connections of the AWWA C515 NRS gate valves were developed for gas industry use in the late 1920s but has since been used extensively in the water industry. This joint has standardized dimensions and uses the basic principle of the stuffing box and gland, with a rubber gasket being compressed by the gland at the joint bell.

Figure-2: A typical drawing for the mechanical joint (MJ) end connection of AWWA C509 or C515 ductile iron gate valves.

As illustrated in Figure-2, the mechanical joint (MJ) end connection of an AWWA C515 gate valve is a bolted joint of the stuffing-box type. Each mechanical joint shall consist of (1) a plain-end ductile iron pipe or fitting; (2) T-head bolts and hexagonal nuts; (3) a follower gland with bolt holes; (4) a joint bell that is cast integrally with the valve body, and provided with an exterior flange having bolt holes or slots, and a socket with annular recesses for the sealing gasket and the plain end of the ductile iron pipe or fitting; (5) a sealing gasket.

Figure-3: The typical drawing for an AWWA C515 mechanical joint end gate valve with non-rising stem and resilient seated wedge.

The assembly process for the mechanical joint connection begins with cleaning and lubricating the plain-end ductile iron pipe or fitting. The sealing gasket is then slid onto the pipe end, followed by the placement of the follower gland over the gasket. The pipe end is inserted into the joint bell, resting on the annular recess of the socket. T-head bolts and hexagonal nuts are inserted through the bolt holes in the follower gland and the corresponding holes or slots in the joint bell’s exterior flange. Finally, the nuts are tightened in a star pattern using a torque wrench to evenly compress the gasket and secure a watertight seal.

The mechanical joint (MJ) end connection of AWWA C515 gate valves presents several advantages for piping systems, including ease of installation without specialized tools or welding, flexibility to accommodate misalignments and thermal expansion, reliability ensured by secure compression of the gasket, easy maintenance with simple disassembly and reassembly, and versatility due to compatibility with various ductile iron pipes and fittings. These features collectively enhance the efficiency, resilience, and cost-effectiveness of fluid transport systems, making MJ end connections a preferred choice for a wide range of applications in water distribution, sewage, and other fluid transport networks.