A method of making a three-flow-passage valve with a pressure indicator, comprising the steps of constructing a first half housing defining an upper flow passage, a middle flow passage, and a lower flow passage; constructing a second half housing defining the same flow passages; forming an access port through the housing in the middle flow passage; forming a first valve seat with one valve opening; assembling one movable valve opening stopper in the upper flow passage; adjusting the one movable valve opening stopper; forming a second valve seat with one valve opening; assembling one movable valve opening stopper in the upper flow passage; adjusting the one movable valve opening stopper to allow the one movable valve opening stopper in the middle flow passage; combining and sealing the first half housing with the second half housing; and mounting a pressure indicator to the access port.

An air admittance valve that includes a base, a flow control member, a diaphragm, and a cap. The base is open at its ends and includes an interior, an exterior, and a sidewall with at least a first port in the sidewall. The flow control member extends transverse across the interior of the base and includes a cavity aligned and in communication with the first port. The flow control member includes a central opening in the top side that is in communication with the cavity. The cap is selectively connected to the base and includes one or more openings in a sidewall that permit fluid to flow into the cavity. The diaphragm prevents a flow of fluid from the interior of the base into the cavity and permits a flow of fluid from the cavity of the flow control member into the interior of the base.

An apparatus to allow or stop a flow into a piping system or an enclosed environment comprises a housing having an upper flow passage, a gasket, and a lower flow passage, wherein said gasket is between said upper flow passage and said lower flow passage, wherein said gasket has an inner diameter less than an inner diameter of said upper flow passage; a rotary valve inside said housing, wherein said rotary valve further comprises a main body and two guides affixed to said main body in opposition to each other, wherein said main body of said rotary valve is configured to be between said inner diameter of said gasket and said inner diameter of said upper flow passage, and wherein said rotary valve can move inside said upper flow passage and above said gasket; and two guide rails inside the upper flow passage.

An apparatus to allow or stop an air flow into an enclosed environment or piping system comprises (a) a housing, (b) a first valve seat, (c) a first sealing member, (d) a second valve seat, (e) a second sealing member, (f) at least one locking mechanism configured to limit a movement of the first sealing member and/or the second sealing member; wherein the first sealing member moves away from the first valve seat when the second pressure is greater than the first pressure in a predetermined pressure difference; wherein the second sealing member moves away from the first valve seat when the third pressure is greater than the second pressure in a predetermined pressure difference; wherein the first pressure communicates with a system pressure in the piping system; and wherein the third pressure communicates with an ambient air pressure.

A toilet modified for disposal of dialysis waste includes a base, a bowl, a water supply port, and a dialysis drain port. In the dialysis drain port is an air gap device that establishes a gap between ends of first and second drain tubes of a dialysis machine and a fluid level in the air gap. RO water and effluent from the dialysis machine enter the chamber of the air gap and mix, before being passed along a path from the dialysis drain port to the bowl of the toilet, where it can be dispelled in a sanitary manner in compliant with all pertinent codes and regulations.

An apparatus to allow or stop an air flow into an enclosed environment or piping system comprises (a) a housing, (b) a first valve seat, (c) a first sealing member, (d) a second valve seat, (e) a second sealing member, (f) at least one locking mechanism configured to limit a movement of the first sealing member and/or the second sealing member; wherein the first sealing member moves away from the first valve seat when the second pressure is greater than the first pressure in a predetermined pressure difference; wherein the second sealing member moves away from the first valve seat when the third pressure is greater than the second pressure in a predetermined pressure difference; wherein the first pressure communicates with a system pressure in the piping system; and wherein the third pressure communicates with an ambient air pressure.

An apparatus to allow or stop an air or water passage into an enclosed environment comprises a housing, an air supply outlet, an air intake inlet, a ball, a gasket, an inlet air filter, an outlet air filter, wherein the ball is inside the housing and moves freely inside the housing, wherein the ball can reside on the gasket and temporarily forms seal to stop the air or water passage, and wherein the ball can be lifted by a lifting force to detach with the gasket when the lifting force is created by an pressure difference when ambient pressure above the gasket inside the housing is less than ambient pressure in the air intake inlet and when the lifting force is greater than the weight of the ball, wherein the air or water passage will flow through the housing and the air supply outlet when the ball is lifted.

An air admittance valve which when subjected to a negative pressure condition vents a pipe system to an ambient environment. Generally, the air admittance valve includes a housing, a cartridge, and a sealing member. The housing includes one or more vents disposed in its wall and may be engaged with the pipe system at one end. The cartridge may have one or more inlets defining one or more inlet openings, where the one or more inlets are connected to a central chamber that has an opening with a sealing structure. The sealing member interacts with the sealing structure of the cartridge to allow one-way airflow from the central chamber to the pipe system. The cartridge and sealing member may be inserted into the housing such that the one or more inlet openings substantially align with the one or more vents in the housing.

A vacuum breaker valve is provided, including: a barrel member, a biasing assembly, a water stop gasket and a plate. The biasing assembly is abutted within the barrel member. The water stop gasket is disposed in the barrel member and abuts against the biasing assembly. The water stop gasket has a water stop portion which is deformable to close at least one air passage of the barrel member. The plate is located between the inlet end and the water stop gasket, and its engaging flange structure is blockable, in a direction toward the inlet end, by a shoulder portion of the barrel member. The biasing assembly normally drives the water stop portion of the water stop gasket apart from the at least one air passage to keep the at least one air passage non-closed.

An air admittance valve which when subjected to a negative pressure condition vents a pipe system to an ambient environment. Generally, the air admittance valve includes a housing, a cartridge, and a sealing member. The housing includes one or more vents disposed in its wall and may be engaged with the pipe system at one end. The cartridge may have one or more inlets defining one or more inlet openings, where the one or more inlets are connected to a central chamber that has an opening with a sealing structure. The sealing member interacts with the sealing structure of the cartridge to allow one-way airflow from the central chamber to the pipe system. The cartridge and sealing member may be inserted into the housing such that the one or more inlet openings substantially align with the one or more vents in the housing.