Embodiments of the present disclosure disclose a method and associated device for determining when an air filter needs replaced in an electronic device. The method comprises measuring the power needed to produce a predetermined output in a fan or related device that receives air through the air filter and comparing the measured power to previous measurements. When the amount of power needed is greater than a threshold, a dirty filter message or alert is produced.

An air flow sensor for use with an air filter comprises a tubular housing with a flap that is opened by air pressure, the extent of opening increasing as the surrounding air filter becomes clogged. A terminal on the flap contacts different measurement terminals on the housing, closing individual circuits connected to an indicator, whereby a display shows when the filter is clear and when it is clogged.

A gas meter structure includes a box-shaped body, an inlet mouth and an outlet mouth suited to allow the passage of a gas flow and defined on the box-shaped body, wherein inside the box-shaped body there are a metering device suited to measure one or more parameters for the determination of the gas flow rate, and a filter suited to filter the gas flow. The filter comprises a dust deposit chamber for the dust present in the gas flowing in, the dust deposit chamber having an inlet opening communicating with the inlet mouth of the box-shaped body, a dust collection bottom and a filtering outlet wall provided with through openings; the dust deposit chamber is configured in such a way that the gas flows into it through the inlet opening and flows out of it through the through openings of the filtering outlet wall.

Flow sensors are provided that can monitor flow conditions. The flow sensor includes a gauge that provides a first level of information about flow through the sensor, and an indicator associated with the gauge that can provided a second level of information about flow through the sensor. The indicator might be in the form of a dial that can rotate about the gauge and might include a locked position for monitoring flow and an unlocked position to rotate the dial about the gauge to reposition the dial. A twisted shaft with varying twist rate is provided to convert linear motion to rotational motion for the gauge.

A gas meter is provided. The gas meter has a gas inlet, a gas outlet and a measuring section. A measuring device for thermal flow measurement can be arranged in the measuring section. A filtering device for removing particulate impurities is arranged downstream of the gas inlet. Gas diverted from the main gas flow is supplied to the filtering device for purifying the gas. After the purification, the purified gas is fed to the measuring device arranged downstream of the filtering device.

Flow sensors are provided that can monitor flow conditions. The flow sensor includes a gauge that provides a first level of information about flow through the sensor, and an indicator associated with the gauge that can provided a second level of information about flow through the sensor. The indicator might be in the form of a dial that can rotate about the gauge and might include a locked position for monitoring flow and an unlocked position to rotate the dial about the gauge to reposition the dial. Vanes in the flow sensor remove turbulence in the flow sensor to settle any noise that would otherwise register in the first level of information about flow through the sensor. The plunger with a rounded upstream face also helps to settle any such noise.

A filter assembly includes a conditioning device that conditions a flow of air upstream of a mass air flow sensor. The filter assembly includes a support frame. The filter assembly further includes a filter media coupled to the support frame, the filter media having a dirty side configured to receive a stream of air and a clean side configured to output a stream of air that has been filtered through the filter media. The filter assembly includes a conditioning device coupled to the support frame, the conditioning device positioned in a downstream direction from the clean side of the filter media with respect to the stream of air, the conditioning device offset from the clean side of the filter media by a separation distance.

A multifunctional dust trap for reducing an acoustic noise and dust filtering comprising: an inlet connected to a gas inlet of a gas meter; a chamber, connected to the inlet, to receive a flow of a gas, comprises: a first wall to deflect the flow of the gas in a first direction, wherein the first wall directs the flow of the gas into a cross sectional area of the chamber, which reduces a velocity of the deflected gas such that a centrifugal force guides a plurality of dust particles towards a base of the chamber; and a second wall to deflect the flow of the gas in a second direction; and an outlet, attached to the chamber, to enable an exit of a clean flow of the gas away from one or more flow inlets of a flow tube installed within the gas meter.

An ageing and dust detection system, comprising: a data collection unit configured to collect a plurality of parameters of a gas meter; and a processing unit, configured to: receive the plurality of the parameters of the gas meter; calculate a numerical value of the plurality of the parameters; compare the calculated numerical value of the plurality of the parameters with a corresponding predefined higher range of values and a predefined lower range of values for the plurality of parameters; determine a reason of a fault in the gas meter based on the compared values, wherein the reason of the fault in the gas meter is at least one of, a presence of a dust, an ageing of the gas meter, or a combination thereof.

A liquid delivery device that includes a channel having an inner section lower than 9 mm.sup.2 and inner volume lower than 50 mL, a gas mass flowmeter connected to the inlet of the channel, and a pressure control unit suitable to control pressure inside the channel by flowing gas through the gas flowmeter.