A vacuum breaker having a supporting rib and a skirted section is disclosed. The supporting rib is configured to be axially aligned with air slots in an outlet tube and provide a more robust vacuum breaker sleeve under extreme operating conditions. The skirted section can prevent leakage through air slots during high back pressure operating conditions.

A backflow resistant stop valve for an aircraft galley plumbing system comprises a valve body defining an inlet, and inlet chamber, a transfer chamber, an outlet chamber, and an exit. The valve incorporates an anti-backflow device at the exit to prevent backflow, and flow through the body is controlled by a pivoting paddle disposed within the valve body having an upper flap, a spindle, and a lower flap, where the upper flap seals against the inlet chamber and the lower flap seals against the outlet chamber when the paddle is rotated to a first position. The valve utilizes a negative pressure at the outlet chamber that biases the valve closed until a sufficient column of water overcomes the bias.

An insertable backflow preventer is presented. The backflow preventer is provided with a cylindrical housing. The housing has a flow transition zone, a proximal orifice/ball seat, a ball with a specific weight that equals or is close to the specific weight of the surrounding fluid, and a distal retaining screen. The housing can have a flange provided on the outside of the housing at one end to facilitate securing the valve in a pipe. The valve is self-cleaning, can be placed in any orientation in a pipe and has low hydraulic head-loss. The valve's unique cost-effective design provides for easy and relative quick installation, eliminates the need to reconfigure existing plumbing, and can be performance tested remotely. Properly installed, it can dramatically improve the security of, for example, potable water sources in a building or other context, and inasmuch as when installed it is not visible, it is tamper proof. The valve can be scaled to any size pipe or tube, and due to its internal flow dynamics is self cleaning. Multiple valves can be installed in series, and balls of varying specific weight can be used in each valve in such a series to allow for contexts where a range of fluids are sent through the same line, or to provide fail-safe operation in the event that contaminants change the specific gravity of the fluid.

A valve member assembly includes a housing, a check valve assembly, and a float valve assembly. The housing is a cup, a retainer and a bonnet releasably secured together. The check valve assembly is positioned within the cup, and the float valve assembly is positioned between the bonnet and the retainer. The valve member assembly can be easily assembled and inserted into a valve body.