Intrinsic safety type vortex street flow sensor for oiling machine gas phase recovery measurement

Abstract

The invention discloses an intrinsic safety type vortex street flow sensor for oiling machine gas phase recovery measurement. The intrinsic safety type vortex street flow sensor comprises a sensor body and a safety barrier with an explosion-proof function. The sensor body comprises a shell; the circulation cavities in the inlet end and the outlet end are both of a structure which is gradually necked down from outside to inside; a piezo-electric crystal is arranged at the top of the circulation cavity in the middle of the shell, and a vertically-arranged turbulence column is arranged in the circulation cavity between the piezo-electric crystal and the inlet end; the shell provided with the turbulent flow column, the inlet end and the outlet end is of an integrally formed structure; the piezo-electric crystal is electrically connected with a filtering and amplifying circuit arranged on the circuit board; and a top cover is arranged on the shell at the upper part of the circuit board. After the gas phase entering the device passes through the turbulent flow column, Karman vortexes are formed at the circulation cavity at the lower part of the piezoelectric crystal, and weak pulse charge signals formed by the Karman vortexes are detected through the high-sensitivity piezoelectric crystal so that the detection of gas phase flow is realized, and the sensitivity is high and the reaction speed is high.

Description

technical field [0001] The invention belongs to the technical field of flow sensors, in particular to an intrinsically safe vortex flow sensor for gas phase recovery measurement of a fuel dispenser. Background technique [0002] With the enhancement of national environmental protection awareness, more and more attention has been paid to the recovery and detection of volatile organic compounds such as oil and gas in gas stations. At present, most of the detection of the gas phase flow in the oil gas recovery is carried out by installing a Roots flowmeter or a thermal flow meter on the gas phase recovery pipeline of each fuel gun on the gas station in the gas station. Among them, the Roots flowmeter belongs to the positive displacement flowmeter. Its detection accuracy is relatively high and its volume is relatively large. However, its high precision requires the installation of a separate filter device when used. Installing a filter device with high filtration accuracy will i...

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Problems solved by technology

Among them, the Roots flowmeter belongs to the positive displacement flowmeter. Its detection accuracy is relatively high and its volume is relatively large. However, its high precision requires the installation of a separate filter device when used. Installing a filter device with high filtration accuracy will increase the gas phase recovery. Pressure, resulting in a decline in recovery efficiency, the installation of a filter device with low filtration accuracy will cause the Roots flowmeter to stall and other situations, resulting in failure to use normally, and its large volume requires a large installation space

The thermal flowmeter belongs to the velocity flowmeter, and the reaction speed in the detection of the gas phase flow is slow, and sometimes it cannot accurately reflect the real gas phase flow.

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