A fine dust concentration sensor includes a bulk acoustic resonator and a cap including an upper portion with holes therein and a lateral portion connected to the upper portion to accommodate the bulk acoustic resonator. An upper surface of the upper portion of the cap is coated with a hydrophobic material.

Microfabricated PM sensors measure concentrations of particulate matter (PM) in air. Some sensors improve the accuracy of measurements by accounting for the effect of ambient conditions (e.g., temperature or humidity) on mass-sensitive elements employed to determine a mass of the PM in a stream of air. Some sensors improve the accuracy of measurements by controlling humidity in the stream of air measured by mass-sensitive elements. Some sensors employ a plurality of mass-sensitive elements to extend the useful life of the PM sensor. Some sensors employ one or more mass-sensitive elements and heating elements to cause deposition and allow measurement of different sizes of PM. Some sensors can measure mass concentration of coarse PM in addition to fine PM in a stream of air. Some sensors control the flow rate of a stream of air measured by mass-sensitive elements. Some sensors include features to mitigate electromagnetic interference or electromagnetic signal loss.

A turbidity measurement device for measuring turbidity of a fluid flowing in a flow tube. A first transducer transmits ultrasonic signals through the fluid in the turbidity measurement section so as to provide a first ultrasonic standing wave between the first and second section ends. A receiver transducer receives the ultrasonic scattered response from particles in the fluid flowing through the turbidity measurement section. A control circuit operates the transducers and generates a signal indicative of the turbidity of the fluid in response to signals received from the receiver transducer. Preferably, the device may comprise a second transducer for generating a second ultrasonic standing wave with the same frequency, and further the two transducers may be used to generate a measure of flow rate by means of known ultrasonic techniques. This flow rate may be used in the calculation of a measure of turbidity. Both turbidity facilities and flow rate facilities may be integrated in a consumption meter, such as a heat meter or a water meter.

A turbidity measurement device for measuring turbidity of a fluid flowing in a flow tube. A first transducer transmits ultrasonic signals through the fluid in the turbidity measurement section so as to provide a first ultrasonic standing wave between the first and second section ends. A receiver transducer receives the ultrasonic scattered response from particles in the fluid flowing through the turbidity measurement section. A control circuit operates the transducers and generates a signal indicative of the turbidity of the fluid in response to signals received from the receiver transducer. Preferably, the device may comprise a second transducer for generating a second ultrasonic standing wave with the same frequency, and further the two transducers may be used to generate a measure of flow rate by means of known ultrasonic techniques. This flow rate may be used in the calculation of a measure of turbidity. Both turbidity facilities and flow rate facilities may be integrated in a consumption meter, such as a heat meter or a water meter.

The present disclosure provides an aerosol sensing method. The aerosol sensing method includes steps of providing an entering process, providing a particle collecting process and providing a measuring process. The entering process is to allow an aerosol to enter a chamber of a thermal-piezoresistive oscillator-based aerosol sensor, and a thermal-piezoresistive resonator is disposed in the chamber. The particle collecting process is to allow particulate matters in the aerosol to land on at least one proof-mass of the thermal-piezoresistive resonator when the thermal-piezoresistive resonator is not driven. The measuring process is to use an electrical signal to drive the thermal-piezoresistive resonator and measure a resonant frequency of the thermal-piezoresistive resonator. The particle collecting process and the measuring process are operated in a repetitive cycle for measuring changes of the resonant frequency of the thermal-piezoresistive resonator to measure the particulate matters of the aerosol.

Apparatus features a signal processor or processing module configured at least to: receive signaling containing information about acoustic emissions resulting from particles impacting a solid sensor element configured in a process pipe having a process fluid flowing therein, including a slurry; and determine particle sizes of solids in the process fluid, based at least partly on the signaling received. The signal processor module may also be configured to provide corresponding signaling containing information about the particle sizes of solids in the process fluid.

A dust mass measurement device includes a sensing channel configured to generate a sensing clock signal, a reference channel configured to generate a reference clock signal, a counter configured to generate a first output signal based on the sensing clock signal, and generate a second output signal based on the reference clock signal, and a controller configured to calculate a frequency difference between the sensing clock signal and the reference clock signal based on a difference value between the first output signal and the second output signal, which are received from the counter, and measure a mass of dust based on the calculated frequency difference.

A fluid sensor assembly includes a body including a fluid passage, a first sensor connected to the body and directed toward the fluid passage, and a second sensor connected to the body and directed toward the fluid passage. At least one of the first sensor and the second sensor may be configured to transmit a signal into the fluid passage. At least one of the first sensor and the second sensor may be configured to receive at least a deflected version of the signal. The signal may include an ultrasonic pulse. The first sensor may include a focused transmitting transducer and the second sensor may include a non-focused receiving transducer. The fluid passage may include a longitudinal axis and the first sensor may be disposed at an oblique angle relative to the longitudinal axis.

A consumption meter, e.g. a water or heat meter, for measuring a flow rate of a fluid supplied in a flow tube. First and second ultrasonic transducers are arranged at the flow tube for transmitting and receiving ultrasonic signals transmitted through the fluid and operated by a flow measurement sub-circuit for generating a signal indicative of the flow rate of the fluid. A noise measurement sub-circuit operates a sensor arranged at the flow tube for detection of acoustic signals of the flow tube, and being arranged to generate a signal indicative of a noise level of the flow tube accordingly. This sensor may comprise a separate transducer, or the sensor may be constituted by one or both of the first and second ultrasonic transducers. The consumption meter may communicate data representative of the noise level via a communication module along with data consumed amount of water, heat etc. Such consumer noise level measurement at the consumer site allows collection of noise level data to assist in locating fluid leakages in a fluid supply pipe system.

Embodiments of the present disclosure include a method including receiving first impact data. The method includes receiving second impact data. The method includes applying a first filter to both the first impact data and the second impact data. The method includes applying a second filter to both the first impact data and the second impact data. Filtering includes time and frequency based discriminating filter to isolate specific signatures that representatively indicate impact signatures generated by the sand on the interrogator. The method includes comparing the first impact data and the second impact data for corresponding signatures. The method includes identifying a corresponding signature in both the first impact data and the second impact data. The method includes determining the corresponding signature meets a threshold criterion. The method includes determining one or more particulate properties based at least in part on the corresponding peak.