Target type flowmeter of non-contact type displacement sensor

Abstract

The invention relates to a target type flowmeter of a non-contact type displacement sensor. An elastic element (4) is arranged in a casing (3), a target bar (2) is arranged in the elastic element (4), the lower end is provided with a target piece (1), the upper part of the target bar (2) is provided with a mechanical damping device (5), the top end of the target bar (2) is provided with detection displacement magnetic steel (6), a position corresponding to the detection displacement magnetic steel (6) is provided with a Hall linear displacement sensor (7), and a signal output end of the Hall linear displacement sensor (7) is connected with a microprocessor (8) and a display (9). The Hall linear displacement sensor does not directly contact with the target bar, the influence of the target bar vibration on the sensor is reduced by the mechanical damping device, the Hall linear displacement sensor can not be damaged even if the elastic element end generates plastic deformation, the sensor is far away from a measuring medium, and a high-temperature type flowmeter can be manufactured. The service life of the sensor is prolonged, the measurement accuracy is enhanced, and the product of the target type flowmeter is truly reliable and durable and has low maintenance quantity.

Description

technical field [0001] The invention relates to a flow meter for liquid material measurement and measurement and control, in particular to a target flow meter. Background technique [0002] The current target flowmeter is composed of a target plate, a target rod, a sensor, a signal processor and a display device. The working principle is to measure the force generated by the fluid on the target plate. When the pressure difference is generated when its own kinetic energy passes through the target, and has a force on the target, using the principle that the magnitude of the force is proportional to the square of the medium flow velocity, the force is passed through the sensor installed on the cylinder. The strain gauge and the other end of the lever are installed with a contact force sensor or a capacitive force sensor, which transmits the electrical signal to the microprocessor, and then the microprocessor transmits the calculation result to the display and outputs a 4~20mA s...

AI Technical Summary

Problems solved by technology

[0003] The main defects of the above two target flowmeters are: the installation of strain gauges is difficult to ensure that the top and bottom are flush and symmetrical, which affects the measurement accuracy

The capacitive electrode is installed in the sensor cylinder, and the through hole under the cylinder is usually sealed, but the seal is damaged due to vibration, and the fluid medium enters the cylinder, which damages the capacitive electrode

Moreover, due to the relatively large fluid water hammer force in this way, the load cell is easily damaged by frequent impacts. At present, the elastic elements used in the target flowmeter are either thin metal sheets or special thin-walled circular tubes that are subjected to the medium. The influence of internal working pressure, especially the thin-walled cylinder or thin metal sheet under high-pressure working state is deformed by the internal working pressure, resulting in changes in measurement data and affecting measurement accuracy

In addition to the above two sensor target flowmeters, in recent years a target flowmeter with a Hall linear displacement sensor has tried to solve the aforementioned problems, such as ZL200520092803.0, but this patent mainly has the following problems due to structural defects: 200520092803.0 Double shrapnel is used as the elastic element. The elastic element is not a sealing element. There is also the problem of the sensor being corroded and damaged by the medium. The sensor is closely attached to the outer wall of the shell that is in direct contact with the medium, and the detection medium of the target flowmeter is mostly viscous medium. In order to improve the fluidity of the medium, it is necessary to heat the medium, so the temperature of the detected medium is mostly high-temperature type, higher than 100°C, and the Hall linear displacement sensor is prone to drift in high-temperature medium, which will further cause damage, and is not suitable for high-temperature applications. Measure under

In addition, the detection displacement magnetic steel is installed between the double shrapnel, and the detection displacement is a kind of parallel displacement, which is affected by the dynamics of the medium, and the measurement accuracy is low

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