An improved structure of pressure gauge includes a bottom case, a pressure measurement assembly, a rotating assembly, a fulcrum piece, a coil spring, a scale meter, and an outer case. The pressure measurement assembly is installed above the bottom case and the surface thereof is shaped with concentric circular waves. The rotating assembly includes a sleeve body and a central rod. A fulcrum piece is installed across between the sleeve body and the central rod. A plurality of through holes and a coil retaining base are provided on the fulcrum piece. One end of the coil spring is screwed onto the coil slot and the other end thereof is installed on the coil retaining base. The outer case is located in the outer area of the bottom case and the fulcrum piece. A transparent cover body is installed on top of the outer case.

An overpressure indicator is defined by a housing sized and configured for attachment within a compartment interior, such as an aircraft nacelle. A pressure sensing element disposed within the housing is coupled to an indicator element and is configured to detect a pressure differential between the interior and exterior of the compartment. The indicator element is caused to move in response to a predetermined change in pressure exceeding a threshold pressure differential. The indicator element includes a distal end that is moved to a position exterior of the housing and the compartment, providing a visual indication of an overpressure condition. A reset feature provided on the indicator can only be accessed by first opening the compartment in which the indicator has been mounted. A spring can be provided to assist in the triggering of the indicator member after the threshold pressure differential has been detected.

An overpressure indicator is defined by a housing sized and configured for attachment within a compartment interior, such as an aircraft nacelle. A pressure sensing element disposed within the housing is coupled to an indicator element and is configured to detect a pressure differential between the interior and exterior of the compartment. The indicator element is caused to move in response to a predetermined change in pressure exceeding a threshold pressure differential. The indicator element includes a distal end that is moved to a position exterior of the housing and the compartment, providing a visual indication of an overpressure condition. A reset feature provided on the indicator can only be accessed by first opening the compartment in which the indicator has been mounted. A spring can be provided to assist in the triggering of the indicator member after the threshold pressure differential has been detected.

A diaphragm pressure gauge, in which a measuring spring is monitored in regard to integrity in that on the side, facing away from the process pressure, of the measuring spring a vacuum chamber is formed to which vacuum is applied and which is controlled by means of a vacuum monitoring device to maintain the vacuum.

A catheter assembly incorporating a pre-biased indicator, the assembly includes a catheter having a proximal end, a distal end, and catheter walls defining a catheter lumen. The assembly further includes a base located at the proximal end of the catheter, the base defining an opening to the catheter lumen, the base having a first end and a second end. An inflatable balloon having a predetermined fill volume is located at a distal end of the catheter. An inflation valve is located on the base; the inflation valve is in fluid communication with the balloon through an inflation lumen defined by the catheter walls. The pre-biased indicator located on the base in fluid communication with the balloon is configured to provide a discrete visual signal that the pressure of a fluid in the balloon is different from a predetermined level of pressure or the volume of the balloon is different from the predetermined fill volume.

A steel measuring element is provided. The steel measuring element is made of an austenitic chromium-nickel steel with a low carbon and nitrogen content for measuring pressure, with an edge zone being provided with increased hardness.