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, a first end of the anti-leak spring abuts against the protrusion, and a second end of the anti-leak spring contacts with the protection unit. The resilient element is received in the receiving portion of the drive element. The cap includes a seat, a push bolt, and multiple passages. An end of the resilient element contacts with the cap.

A display structure of a pressure gauge of an air compressor, the air compressor is received in an accommodation box, and a scale portion of the pressure gauge is viewable via a displaying opening of the accommodation box, the pressure gauge includes a cylindrical body which is transparent and is formed in a pen shape, and the pressure gauge includes a colored O-ring configured to indicate a pressure value of the scale portion. The scale portion is not printed on the cylindrical body of the pressure gauge and includes a transparent panel on which the pressure value of the scale portion is marked on an internal face of the transparent panel, and the internal face faces the cylindrical body of the pressure gauge.

An indicator adapted to provide a visual indication of an over pressure situation in a system. The indicator (also referred to as a pop indicator), includes a main body, a piston that is disposed in the main body, and one or more O-rings disposed around the piston. Initially, the piston is in a first position where the piston is retracted into the body. However, when an over pressure situation occurs, the pressure causes the piston to move in a direction out of the main body against a friction force created by the O-ring. When the piston is moved, i.e., popped, then end of the piston extending out of the body provides a visual indication.

Embodiments of a valve assembly and a plumbing system incorporating the same are provided herein. In some embodiments, a valve assembly for use with an enclosed environment includes a housing having an interior volume, an inlet disposed at a first end of the housing and fluidly coupled to an environment surrounding the housing, and an outlet disposed at a second end of the housing opposite the first end and fluidly coupled to the enclosed environment; a first valve having a first valve seat and a first sealing member at least partially extending through a first opening in the first valve seat in a closed position; and a second valve disposed beneath the first valve and having a second valve seat and a second sealing member at least partially extending through a second opening in the second valve seat in a closed position.

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.

An air inflation device includes an inflation unit defining an interior space, a handgrip unit connected to the inflation unit, and a pressure measuring mechanism disposed in the handgrip unit and including a first tubular member defining a receiving space, and a second tubular member defining a flow guide channel that has an air inlet communicating with the interior space, and an air guide hole communicating with the receiving space. A measuring unit is disposed in the receiving space and has a free end pushed to move relative to the first tubular member by air entering the receiving space from the flow guide channel. An indicating unit indicates a position of the free end in the first tubular member.

A device and method for the visual inspection of the existence of pressure within a branch line of pipe is described. A mechanical tee includes a collar portion configured to extend around a pipe. The collar portion defines an axis and includes one or more fasteners to secure the tee to the pipe. A neck portion is coupled to the collar portion. The channel of the neck portion is in fluid communication with the interior of the pipe. A seal is used to prevent leakage between the pipe and the mechanical tee. A pressure indicating device is in fluid communication with the channel of the neck portion and configured to provide a visual indication of the pressure level in the channel. The pressure indicating device may optionally include electrical contacts to communicate with a monitoring system to discern and track the pressure levels in the channel.

A pressure detection device is mounted within an actuator housing between a piston rod and the housing, to receive fluid leaked past a seal, via a bore in the housing. The pressure detection device is configured to provide an output indicative of the pressure or flow of the leaked fluid in the bore. Thus, the leaked fluid diverted via the bore operates the pressure detection device to provide an output indicative of leakage.

A high pressure gauge contains: a body, a support, a film, a cylinder, an indicator, a screw element, a stud, and a push post. The stud has a channel through which the push post passes, and the stud has a seal ring contacting with the push post in the channel. A central disc is defined between the film and a circular tab of the screw element, the central disc contacts with the film, the push post includes a C retainer engaged on an extension of the push post, and the C retainer is defined between the screw element and the stud. When the push post moves, the C retainer abuts against the stud, and an auxiliary ring is received in the channel, located above and contacts with the seal ring and the extension of the push post. The seal ring is concave, and the auxiliary ring is convex.

A device and method for the visual inspection of the existence of pressure within a branch line of pipe is described. A mechanical tee includes a collar portion configured to extend around a pipe. The collar portion defines an axis and includes one or more fasteners to secure the tee to the pipe. A neck portion is coupled to the collar portion. The channel of the neck portion is in fluid communication with the interior of the pipe. A seal is used to prevent leakage between the pipe and the mechanical tee. A pressure indicating device is in fluid communication with the channel of the neck portion and configured to provide a visual indication of the pressure level in the channel. The pressure indicating device may optionally include electrical contacts to communicate with a monitoring system to discern and track the pressure levels in the channel.