Embodiments of air admittance valve assembly and plumbing system incorporating the same are provided herein. In some embodiments, a valve assembly to allow or stop a flow for use with enclosed environment includes a housing having, an inlet disposed at a first end of the housing fluidly coupled to environment surrounding housing, an outlet disposed at a second end of housing fluidly coupled to enclosed environment, and an interior volume divided into a first zone, a second zone, and a third zone; a first valve having a first valve seat and a first sealing member urged by an existing force between a closed or open position; and a second valve having a second valve seat and a second sealing member urged by an existing force between a closed or open position.

A pressure gauge includes a hollow tube, a drive element, an anti-leak spring, a resilient element, and a cap. The hollow tube includes an accommodation chamber, a connector having a conduit, and a display unit. The drive element includes a protection unit, a first open segment, a second distal segment, a receiving portion, a hollow extension, and a protrusion. An anti-leak spring is received in the hollow extension of the drive element and abuts against the protrusion and the protection unit. The resilient element is received in the receiving portion. The cap includes a seat, a push bolt, and multiple passages. The accommodation chamber has a first fixing section and a second fixing section, a diameter of which is different from that of the first fixing section. The hollow tube further includes a tilted surround section and at least one discharge orifice.

A pressure gauge has a shell, a scale panel, an index pointer, a piston set, and a gear transmission set. The shell has a front end board, a back end board, and a piston base mounted on the inner surface of the back end board. The scale panel is mounted between the front end board of the shell and the back end board of the shell. The index pointer is mounted on a front surface of the scale panel. The piston set is mounted in the piston base of the shell. The gear transmission set is mounted between the back end board of the shell and the scale panel.

Embodiments of air admittance valve assembly and plumbing system incorporating the same are provided herein. In some embodiments, a valve assembly comprising a housing, a first valve comprising a first valve sealing member and a first valve seat, and a second valve comprising a second valve sealing member and a second valve seat, and a pipe, an inlet, an outlet, a first zone, a second zone, a third zone, the first and second valve sealing member is closed by gravity and open based upon the pressure differential between the first zone, second zone and third zone.

A height adjustable hitch receiver is disclosed and described.

A pressure indicator includes a body, a piston, first and second biasing elements, and a rotatable disc. The piston is disposed at least partially in a bore of the body at a first longitudinal axial position relative to the body when pressure of fluid acting on the base is below a threshold pressure. The first biasing element is disposed between a base of the piston and a shoulder of the body, wherein a force of the first biasing element is overcome by pressure of fluid acting on the base at or above the threshold pressure, thereby allowing the piston to move to a second longitudinal axial position. The rotatable disc has a first rotational position when the piston is in the first axial position. The second biasing element is configured to urge the disc to a second rotational position when the piston is in the second axial position.

A height adjustable hitch receiver is disclosed and described.

Disclosed is a method and an apparatus for measuring the pressure of fresh concrete and similar liquid materials during placement, in which a movable component is displaced under the pressure of concrete or other liquids and is used as an indicator of the pressure exerted by the concrete or liquid material on the device. Mechanical resistance of the movable component is achieved using a calibrated spring or similar mechanical resistance element. The movable part consists of a pressure plate attached to a scaled cylindrical core, calibrated to provide measurements of the external concrete or liquid pressure. The movable component and mechanical resistance element are installed in a casing with flanges to attach the apparatus to the formwork or vessel.

A gauge for a hybrid pressure and flowgauge regulator includes first indicia and second indicia. The first indicia provides an indication of a flow rate of a gas exiting an outlet of the hybrid pressure and flowgauge regulator when the gas exits with a pressure below a gauge threshold pressure. The second indicia provides an indication of the pressure of the gas exiting the outlet of the hybrid pressure and flowgauge regulator when the pressure of the gas exiting the outlet is above the gauge threshold pressure.

An air compressor having a pressure gauge, the pressure gauge contains: a hollow tube, a drive element, an anti-leak spring, a resilient element, and a cap. The hollow tube includes an accommodation chamber, a connector having a conduit, and a display unit. The drive element includes a protection unit, a first open segment, a second distal segment, a receiving portion, a hollow extension, and a protrusion. An anti-leak spring is received in the hollow extension of the drive element and abuts against the protrusion and the protection unit. The resilient element is received in the receiving portion. The cap includes a seat, a push bolt, and multiple passages. The accommodation chamber has a first fixing section and a second fixing section, a diameter of which is different from that of the first fixing section. The hollow tube further includes a tilted surround section and at least one discharge orifice.