Abstract: A valve diaphragm for a relief valve may include: a body having a first beaded end and a second beaded end, the first beaded end having a bottom surface and a bulge extending from the bottom surface. The bottom surface may be configured to contact a first portion of a corner of a lower valve body, and the bulge is configured to contact a step of an upper valve body, and the engagements of the bottom surface, the first portion of the corner, the bulge, and the step may be configured to create a fluid tight seal between the upper valve body and the lower valve body.

Abstract: A spring stop arrangement for a check valve may include: a check seat defining a flow path; a clapper assembly connected to the check seat and configured to obstruct the flow path, the clapper assembly including: a clapper; and a seal retainer detachably mounted to the clapper; a cam arm connected to the check seat, the cam arm including a stopper; and a torsion spring operatively connected to the cam arm so as to apply a biasing force to the cam arm against the direction of fluid flow. When the seal retainer is dismounted from the clapper, the stopper may be configured to contact the check seat so as to prevent rotation of the cam arm.

Abstract: A backflow prevention device includes a main pipe body extending along a first center longitudinal axis, at least one check valve disposed within the main pipe body, an inlet pipe connected to an inlet side of the main pipe body, and an outlet pipe connected to an outlet side of the main pipe body. The inlet pipe and the outlet pipe extend along a second center longitudinal axis. The first center longitudinal axis is offset with respect to the second center longitudinal axis in a direction perpendicular to the first and second center longitudinal axes. A center of the valve seat of the at least one check valve is offset with respect to the second center longitudinal axis in the direction perpendicular to the first and second longitudinal axes.