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 measurement device is configured to adjust a gas pressure in an external gas cavity that is fluidly coupled thereto and measure the adjusted gas pressure in the external gas cavity. The pressure measurement device includes a port, a pressure control module, a port pressure sensor, and a gas discharging port. The pressure measurement device is fluidly coupled to the external gas cavity through the port. The pressure control module is coupled to the port through a gas passage and configured to operably provide pressurized gas to the external gas cavity or draw gas from the external gas cavity. The port pressure sensor is coupled to the port and configured to measure a gas pressure at the port. The gas discharging port is coupled to the port and the pressure control module, and configured to operably discharge gas from the port or the pressure control module to an external environment.

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 high-precision gas density relay includes a housing, a base, an end seat, a Bourdon tube, a temperature compensation element, a signal regulation mechanism, and a plurality of microswitches. The microswitches are button microswitches. The density relay further includes microswitch contact trigger elements made of elastic material. One end of each microswitch contact trigger element is fixed inside the housing, and the other end is arranged corresponding to a button of a button microswitch, abutting the button of each button microswitch in one-to-one correspondence. When the gas density value changes, the Bourdon tube and the temperature compensation element generate displacements, which successively drive the microswitch contact trigger elements through the signal trigger mechanism.

A diaphragm seal assembly, which includes a measuring instrument, a pressure being transmitted from a process side to be monitored, via an arrangement of two diaphragms having an evacuated intermediate space disposed therebetween, to the measuring instrument, reliably separated from the process side, the fatigue strength of the diaphragm seal assembly under extreme application conditions being improved.

A pressure transducer comprising a flexible member made of amorphous quartz and a crystalline quartz sensor are coupled together without an adhesive material. Instead, the amorphous quartz and the crystalline quartz sensor are coupled together at the molecular level. In some embodiments, the crystalline quartz sensor remains in compression or tension during the entire operating range of the pressure transducer. In one embodiment, the crystalline quartz sensor is pre-stressed in either compression or tension when the pressure transducer is exposed to atmospheric pressure. In one embodiment, pressure transducer is located in pressure stabilizing system.

A pressure measurement device is configured to adjust a gas pressure in an external gas cavity that is fluidly coupled thereto and measure the adjusted gas pressure in the external gas cavity. The pressure measurement device includes a port, a pressure control module, a port pressure sensor, and a gas discharging port. The pressure measurement device is fluidly coupled to the external gas cavity through the port. The pressure control module is coupled to the port through a gas passage and configured to operably provide pressurized gas to the external gas cavity or draw gas from the external gas cavity. The port pressure sensor is coupled to the port and configured to measure a gas pressure at the port. The gas discharging port is coupled to the port and the pressure control module, and configured to operably discharge gas from the port or the pressure control module to an external environment.

A diaphragm seal assembly, which includes a measuring instrument, a pressure being transmitted from a process side to be monitored, via an arrangement of two diaphragms having an evacuated intermediate space disposed therebetween, to the measuring instrument, reliably separated from the process side, the fatigue strength of the diaphragm seal assembly under extreme application conditions being improved.

A pressure transducer comprising a flexible member made of amorphous quartz and a crystalline quartz sensor are coupled together without an adhesive material. Instead, the amorphous quartz and the crystalline quartz sensor are coupled together at the molecular level. In some embodiments, the crystalline quartz sensor remains in compression or tension during the entire operating range of the pressure transducer. In one embodiment, the crystalline quartz sensor is pre-stressed in either compression or tension when the pressure transducer is exposed to atmospheric pressure. In one embodiment, pressure transducer is located in pressure stabilizing system.

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.