A fuel sensing system utilizes non-contact plastic optical fiber (POF) to optically sense the level of liquid fuel in a fuel tank. In one implementation, the fuel level sensing system includes the following elements: (i) a high-speed and high-power red laser diode; (ii) an ultra-high-sensitivity photon-counting avalanche photodiode; and (iii) a large-diameter and large-numerical-aperture graded-index POF. The fuel level is sensed when the avalanche photodiode first detects impinging light reflected by the POF end face and then detects impinging light reflected by the fuel surface in response to emission of a laser pulse by the red laser diode. A time delay detection circuit calculates the time interval separating the respective times of arrival. A fuel level calculator calculates the fuel level based on the time interval provided by the time delay detection circuit.

Systems and methods that use a differential spectral liquid level sensor to measure the level of liquid in a reservoir (e.g., a fuel tank or other storage container). The use of a differential spectral liquid level sensor solves the problem of common-mode intensity variations (i.e., intensity variations not due to the level of the liquid) by having two different wavelengths propagate through the same optical path but have different spectral attenuations in the liquid. By determining the ratio of the received optical powers, common-mode intensity variations can be neutralized, thereby enhancing the accuracy of the received power reading and the resulting liquid level indication.

A fuel sensing system utilizes non-contact plastic optical fiber (POF) to optically sense the level of liquid fuel in a fuel tank. In one implementation, the fuel level sensing system includes the following elements: (i) a high-speed and high-power red laser diode; (ii) an ultra-high-sensitivity photon-counting avalanche photodiode; and (iii) a large-diameter and large-numerical-aperture graded-index POF. The fuel level is sensed when the avalanche photodiode first detects impinging light reflected by the POF end face and then detects impinging light reflected by the fuel surface in response to emission of a laser pulse by the red laser diode. A time delay detection circuit calculates the time interval separating the respective times of arrival. A fuel level calculator calculates the fuel level based on the time interval provided by the time delay detection circuit.

In a liquid level monitor for use with a liquid container of a liquid-consuming device, a light source transmits a light beam into the liquid container at a non-normal angle of incidence respective to a wall of the liquid container. A photodetector is positioned in the path of one of (i) the light beam after passing through the liquid container when the light beam is not refracted by liquid in the liquid container and (ii) the light beam after passing through the liquid container when the light beam is refracted by liquid in the liquid container. In another approach, the sensor for detecting empty includes a vibrator and a vibration sensor, and an electronic processor is programmed to determine whether the liquid container is empty of liquid based on the detected vibration of the liquid container.

A method for collecting and analyzing operational information from a network of components associated with a liquid energy commodity comprises the steps of: (a) measuring an amount of the liquid energy commodity in storage at one or more storage facilities in the network, and storing that measurement data; (b) determining a flow rate of the liquid energy commodity in one or more selected pipelines in the network, and storing that flow rate data; (c) ascertaining an operational status of one or more processing facilities in the network, and storing that operational status information; (d) analyzing the measurement data, the flow rate data, and the operational status information to determine a balance of the liquid energy commodity in the network or a selected portion thereof at a given time; and (e) communicating information about the balance of the liquid energy commodity to a third-party market participant.

A liquid level detection system and a liquid level detection method comprising a light source, a light guiding medium, a photoelectric conversion receiver and a processing module is provided. The light guiding medium has an incident surface, a first reflection surface, and an exiting surface. The first reflection surface comprises a first sub-reflection surface and a second sub-reflection surface, with a liquid surface as a boundary line. When the light beam is incident on the first and second sub-reflection surfaces at the same angle, the refraction angle and light intensity loss is different, so there is an abrupt change in the generated light intensity image. The position of the abrupt change is the position of the liquid surface. The position of the liquid surface can thereby be obtained according to the position of abrupt change in light intensity after the light beam passes through the light guiding medium.

A trap bowl is provided to accumulate liquid droplets from a filter, as a liquid content. The trap bowl includes a transparent vertical prism. The transparent vertical prism includes a face that forms a vertical transparent surface facing against a content of the section. The face can provide a first angle of total reflection when content of the section is a type of gas, and a second angle of total reflection when the content of the section is the liquid content. A light source may emit a light beam incident on the face at an angle of incidence. The angle of incidence results in reflection of the light beam, striking the light receiver, when the face has the first angle of total reflection, and results in refraction of the light beam, missing the light receiver, when the face has the second angle of total reflection.

A trap bowl is provided to accumulate liquid droplets from a filter, as a liquid content. The trap bowl includes a transparent vertical prism. The transparent vertical prism includes a face that forms a vertical transparent surface facing against a content of the section. The face can provide a first angle of total reflection when content of the section is a type of gas, and a second angle of total reflection when the content of the section is the liquid content. A light source may emit a light beam incident on the face at an angle of incidence. The angle of incidence results in reflection of the light beam, striking the light receiver, when the face has the first angle of total reflection, and results in refraction of the light beam, missing the light receiver, when the face has the second angle of total reflection.

An optical operating fluid detector for optical detection of operating fluid for a hand-guided garden, forestry and/or construction machining appliance includes a light source, an operating fluid line and a light receiver. The light source is designed for radiation of rays of light. The operating fluid line is designed for optical interaction of rays of light from the light source with operating fluid in line for the optical detection of operating fluid. The light receiver is designed for differing reception of rays of light from the line in dependence on the presence or the absence of operating fluid in the line. The operating fluid detector has an optical deflecting device. The deflecting device is designed for deflection of rays of light from the light source to the operating fluid line and/or for deflection of rays of light from the line to the light receiver. The operating fluid line is designed for differing diversion of rays of light from the light source in dependence on the presence or the absence of operating fluid in the line for optical detection of operating fluid.

Systems and methods that use a differential spectral liquid level sensor to measure the level of liquid in a reservoir (e.g., a fuel tank or other storage container). The use of a differential spectral liquid level sensor solves the problem of common-mode intensity variations (i.e., intensity variations not due to the level of the liquid) by having two different wavelengths propagate through the same optical path but have different spectral attenuations in the liquid. By determining the ratio of the received optical powers, common-mode intensity variations can be neutralized, thereby enhancing the accuracy of the received power reading and the resulting liquid level indication.