The invention relates to a density monitor (10) for monitoring a gas density in a gas chamber (20). The density monitor (10) comprises a measuring apparatus (12) having a first measuring device (24) and a second measuring device (28), the two measuring devices (24; 28) being coupled together. The first measuring device (24) is designed to measure a first pressure range (62) in relative terms with respect to an atmosphere, and the second measuring device (28) is configured to measure a second pressure range (64) in absolute terms. The density monitor (10) further comprises an indicator device (50), which is designed to indicate the two pressure ranges (24; 28). The density monitor (10) also comprises a movable drive element (48), which is designed to drive the indicator device (50), wherein at least one of the two measuring devices (24; 28) is designed to move the drive element (48) in order to drive the indicator device (50), wherein the indicator device (50) comprises an indicator element (58) which is designed to indicate the two pressure ranges (62, 64).

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.

Provided are a maintenance-free gas density relay and a mutual check method therefor. The maintenance-free gas density relay includes a gas density relay body and first gas density detection sensors which are in communication on gas paths, and an intelligent control unit connected to the gas density relay body and the first gas density detection sensors separately, where the intelligent control unit compares and checks a first pressure value and a second pressure value acquired at the same gas pressure, and/or compares and checks a first temperature value and a second temperature value acquired at the same gas temperature, or compares and checks a first density value and a second density value acquired at the same gas density, and can further upload received data to a background for data comparison by the background. The present disclosure further completes online self-check or mutual check of the gas density relay while being used for monitoring gas density of a gas-insulated or arc-control electrical apparatus, thereby improving efficiency, avoiding maintenance, reducing cost, and ensuring safe operation of a power grid.

A pressure gauge with divisional scale includes a piston tube, a piston, an elastic member, a rotating member and a pointer connected with the rotating member. The piston has plural transmission portions and is slidably disposed in the piston tube. The elastic member is disposed inside the piston tube and abutted against the piston. The rotating member has plural gears sequentially and respectively engaged with the transmission portions when the piston slides so as to drive the pointer to swivel, thereby achieving a pressure gauge with a single pointer indicating multiple pressure ranges.

Provided is a pressure gauge capable of being effectively used for internal pressure measurement of a balloon catheter and capable of providing easy monitoring of a pressure value even when measuring internal pressure of an extracorporeal circulation circuit. The pressure gauge measures internal pressure of a balloon catheter used for treatment and diagnosis or pressure of a body lumen of a living body and includes a coil-shaped tube 2 to elastically deform. One end of the tube 2 is set as an open fixed end and the other end is set as a sealed free end and pressure introduced from the open fixed end can be measured based on a displacement position of the tube 2 due to the pressure.

A pressure gauge includes a housing, a helical tube, and a compensation member. The housing has an inlet. The helical tube is arranged within the housing and has a closed end and an open end, the open end of the helical tube in fluid communication with the inlet. The compensation member is arranged between the between the open end and the closed end of the helical tube, the compensation member fixed to the helical tube. The compensation member and the helical tube are formed from materials having different coefficients of thermal expansion to limit movement of the closed end of the helical tube due to temperature change of a compressed fluid in fluid communication with the helical tube. Pressure vessel assemblies and methods of displaying pressure in pressure vessels are also described.

A pressure gauge includes an introduction member, a connection member, a bourdon tube, a pointer, a dial plate, a detector, and an information communication unit. A battery installed in the information communication unit is disposed between a circuit board and a lid. The information communication unit is inserted in a through hole of the dial plate to be disposed astride between a front surface and a rear surface of the dial plate and the lid is disposed on a side of the information communication unit close to the front surface of the dial plate.

The invention relates to a pressure gauge for measuring the pressure of a fluid, the pressure gauge being designed for a pressure range with a maximum pressure, with: a housing with a housing wall which is filled with a filling fluid; a pressure connection located in the housing wall; a tubular spring located in the housing and connected to the pressure connection, whereby a fluid can flow through the pressure connection into the tubular spring, whereby the tubular spring is designed to expand in the direction of the housing wall when pressure is applied by the fluid, thereby mechanically acting on an indicator to indicate the pressure of the fluid; and at least one volume reduction element which is at least partially located in the housing between the tubular spring and the housing wall in the direction of expansion of the tubular spring, whereby the at least one volume reduction element is an injection-molded plastic part.

A pressure gauge includes a case with a dial, and a pressure detection unit is located in the case. The chassis plate including a first pivot unit, a second pivot unit, a first Bourdon Tube, a second Bourdon Tube, a first transmission unit, a second transmission unit and an entrance connected thereto. The first Bourdon Tube is connected to the first pivot unit by the first transmission unit, and the second Bourdon Tube is connected to the second pivot unit by the second transmission unit. The entrance communicates with the first and second Bourdon Tubes. The first and second pivot units extend through the dial so as to be connected with a first hand and a second hand respectively. The first and second hands respectively respond different pressure values for more accuracy.

A pressure gauge includes a housing, a helical tube, and a compensation member. The housing has an inlet. The helical tube is arranged within the housing and has a closed end and an open end, the open end of the helical tube in fluid communication with the inlet. The compensation member is arranged between the between the open end and the closed end of the helical tube, the compensation member fixed to the helical tube. The compensation member and the helical tube are formed from materials having different coefficients of thermal expansion to limit movement of the closed end of the helical tube due to temperature change of a compressed fluid in fluid communication with the helical tube. Pressure vessel assemblies and methods of displaying pressure in pressure vessels are also described.