A depth selector or current depth provider for use by a variable speed air system. As a depth selector it is preferably in the form of a rotary switch on the user interface for the air system. The rotary switch can have 3 positions for maximum depth selections, such as, without limitation 15, 25, and 65 feet. Other depth values and number of depth selections provided can be used and all are considered within the scope of the disclosure. A microcontroller of the system reads the voltage from the voltage divider created by the rotary switch selection to determine which position the rotary switch is in. The microcontroller uses this information to set the upper and lower pressure limits for the dive.

A depth selector or current depth provider for use by a variable speed air system. As a depth selector it is preferably in the form of a rotary switch on the user interface for the air system. The rotary switch can have 3 positions for maximum depth selections, such as, without limitation 15, 25, and 65 feet. Other depth values and number of depth selections provided can be used and all are considered within the scope of the disclosure. A microcontroller of the system reads the voltage from the voltage divider created by the rotary switch selection to determine which position the rotary switch is in. The microcontroller uses this information to set the upper and lower pressure limits for the dive.

A curved recess in a stopper includes a groove-pattern region and a groove-free region. When a sensor diaphragm reaches a bottom of the curved recess in the stopper, a groove-free region is divided into a ring-shaped first region with which a sensor diaphragm is in close contact and a ring-shaped second region disposed between an inner wall surface of a ring-shaped wall and the ring-shaped first region. The first region serves as a sealing region and the second region serves as a confinement region so that a pressure transmitting medium that remains in a space adjacent to the inner wall surface of the ring-shaped wall is confined in the confinement region, and abnormal deformation of the sensor diaphragm is prevented.

A differential pressure indicator includes a multi-polar driving magnets train clamped on a piston pin that moves in response to the changes in pressure conditions, thereby driving a multi-polar follower magnet carrying an indicating member, to move across a scale for a total angular range of 90° to 270°. The exact angular displacement of the follower magnet per unit linear displacement of the driving magnets train is decided by varying the relative magnetic strengths of the driving and follower magnets or by varying the spacing between adjacent magnets of the driving magnetic train. Further, magnetic flux of an auxiliary magnet fitted on the piston pin at a 90° orientation relative to the driving magnet train is utilized for actuating a magnetic switch in the switch assembly.

A differential pressure indicator includes a multi-polar driving magnets train clamped on a piston pin that moves in response to the changes in pressure conditions, thereby driving a multi-polar follower magnet carrying an indicating member, to move across a scale for a total angular range of 90° to 270°. The exact angular displacement of the follower magnet per unit linear displacement of the driving magnets train is decided by varying the relative magnetic strengths of the driving and follower magnets or by varying the spacing between adjacent magnets of the driving magnetic train. Further, magnetic flux of an auxiliary magnet fitted on the piston pin at a 90° orientation relative to the driving magnet train is utilized for actuating a magnetic switch in the switch assembly.

A differential pressure sensor is provided with an indicator assembly to represent the measured differential pressure. The sensor includes a cylindrical tube with a magnetic piston slidably disposed within. The indicator assembly is positioned adjacent to the tube and includes a first magnet having a first polarity direction and a second magnet having a second polarity direction. The magnets are provided in the indicator assembly such that the first and second polarity directions are parallel to one another. The first and second magnets are symmetrically disposed and offset from one another about a center of rotation of the indicator assembly.

A pressure gauge contains: a body and a casing. The body includes a scale disc fixed on a top thereof. The casing is transparent and includes a close segment formed on a first end of the casing, an open segment formed on a second end of the casing, and multiple hooks spaced and arranged on an outer wall of the casing proximate to the opening segment.

A pressure gauge contains: a body and a casing. The body includes a scale disc fixed on a top thereof. The casing is transparent and includes a close segment formed on a first end of the casing, an open segment formed on a second end of the casing, and multiple hooks spaced and arranged on an outer wall of the casing proximate to the opening segment.

A gauge including a housing, a measuring port, an opening formed in the housing and a cover for covering the opening. The cover of the gauge is selected from a range of flexible and translucent materials.

A gauge including a housing, a measuring port, an opening formed in the housing and a cover for covering the opening. The cover of the gauge is selected from a range of flexible and translucent materials.