Pressure sensor systems for measuring a liquid pressure and deriving a liquid level from the measured pressure using gas pressure sensing devices. In one embodiment, liquid pressure results in compression or decompression of a trapped gas (as an example, air), wherein the gas pressure is detected by a gas pressure sensing device directly or a gas pressure sensing device that is protected inside a flexible pouch filled with a liquid. In another embodiment, a gas pressure sensing device is packaged in a flexible pouch filled with an inert liquid to protect the sensing device and circuit thereof from external contaminants while accurately transferring pressure from the liquid through a protective barrier. Application of such sensors in a wireless flood or a wireless liquid level measurement system is described as well.

An apparatus for determining the identity and/or quantity of a liquid fuel contained in a fuel transporting tank of a fuel transporting vehicle can comprise: a longitudinally extensive member having a first end and a second end, an internal volume from which liquid fuel in the tank is excluded, and a mounting arrangement configured for mounting in use of the longitudinally extensive member within and in fixed relation to the tank, said second end configured in use to be immersed in the liquid fuel in the tank. The longitudinally extensive member can further comprise: first and second pressure sensors spaced apart by a fixed distance, each said pressure sensor having a face exposed in use to the local hydrostatic pressure of the liquid fuel in the tank; and a colour sensing device comprising a light emitter and a light detector configured to detect light from the emitter, said emitter and detector being arranged such that in use light from the emitter incident on the detector passes through said liquid fuel in the tank. The apparatus can further comprise a data processing device configured to determine the identity of the liquid fuel based on said pressure measurements from said first and second pressure sensors and colour data from said colour sensing device.

In accordance with at least one aspect of this disclosure, a fuel quantity measurement system includes, one or more pressure sensors are configured to operatively connect external to a fuel volume of a fuel tank, and can be operative to sense and output a signal indicative of a pressure outside of the fuel volume. One or more hollow pressure tubes can be configured to be disposed in the fuel volume in the fuel tank. The one or more hollow tubes can have a first end in fluid communication with the fuel volume and a second end configured to be sealed against an ambient environment external to the fuel tank. One or more temperature sensors can be configured to operatively connect within the fuel tank, operative to sense and output a signal indicative of a temperature of the fuel tank.

A car wash additive measuring system and method use a bubbler which provides a flow of pressurized gas through each bulk container. A pressure of each individual flow of pressurized gas is measured by a pressure transducer to output a signal indicative of the level of additive stored in the container. Flow rates of the respective flow of pressurized gas may be adjusted to accommodate particular additives.

The present invention provides a liquid level gage with C-plane sapphire. In an exemplary embodiment, the liquid level gage includes a hood assembly, a liquid column assembly, and an illuminator assembly. In an exemplary embodiment, the liquid column assembly includes a plurality of gage body assemblies. In an exemplary embodiment, each gage body assembly includes a body, a front port assembly, and a rear port assembly. In an exemplary embodiment, each front port assembly and each rear port assembly includes a glass module and a nut module. In an exemplary embodiment, each glass module includes a glass disk. In an exemplary embodiment, each glass disk is formed from C-plane sapphire.

An oil detecting device for a compressor and a compressor including an oil detecting device are provided. A casing in which oil is received has a plurality of capillary tubes in an inner space of the casing, and a condition of oil is detected on the basis of a result of a measured pressure from the plurality of capillary tubes.

A mica water level gauge glass includes a steam tee fitting, a balance pipe, a water tee fitting, a steam connecting pipe, a water connecting pipe, a condensation tank, a longitudinal vertical gauge body, and a mica assembly. The gauge body includes a thermal compensation cavity, a steam-water cavity, an auxiliary heat confluence device, and a horizontal steam cavity. The exit points of the thermal compensation cavity arranged in the gauge body is lower than the point of the steam-water cavity exiting from the gauge body.

A monitoring system for monitoring a water level in a plumbing element. The monitoring system has a sensor unit, which includes at least one sensor for detecting a measured value and with the aid of which a water level in a receiving space of the plumbing element may be ascertained. A plumbing element is also provided that comprises a receiving space for accommodating water and at least one water outlet for emptying the water from the receiving space.

An apparatus for determining the identity and/or quantity of a liquid fuel contained in a fuel transporting tank of a fuel transporting vehicle can comprise: a longitudinally extensive member having a first end and a second end, an internal volume from which liquid fuel in the tank is excluded, and a mounting arrangement configured for mounting in use of the longitudinally extensive member within and in fixed relation to the tank, said second end configured in use to be immersed in the liquid fuel in the tank. The longitudinally extensive member can further comprise: first and second pressure sensors spaced apart by a fixed distance, each said pressure sensor having a face exposed in use to the local hydrostatic pressure of the liquid fuel in the tank; and a colour sensing device comprising a light emitter and a light detector configured to detect light from the emitter, said emitter and detector being arranged such that in use light from the emitter incident on the detector passes through said liquid fuel in the tank. The apparatus can further comprise a data processing device configured to determine the identity of the liquid fuel based on said pressure measurements from said first and second pressure sensors and colour data from said colour sensing device.

An apparatus for determining the identity and/or quantity of a liquid fuel contained in a fuel transporting tank of a fuel transporting vehicle can comprise: a longitudinally extensive member having a first end and a second end, an internal volume from which liquid fuel in the tank is excluded, and a mounting arrangement configured for mounting in use of the longitudinally extensive member within and in fixed relation to the tank, said second end configured in use to be immersed in the liquid fuel in the tank. The longitudinally extensive member can further comprise: first and second pressure sensors spaced apart by a fixed distance, each said pressure sensor having a face exposed in use to the local hydrostatic pressure of the liquid fuel in the tank; and a colour sensing device comprising a light emitter and a light detector configured to detect light from the emitter, said emitter and detector being arranged such that in use light from the emitter incident on the detector passes through said liquid fuel in the tank. The apparatus can further comprise a data processing device configured to determine the identity of the liquid fuel based on said pressure measurements from said first and second pressure sensors and colour data from said colour sensing device.