Pressure sensor having medium isolation measurement module

Abstract

The invention relates to the technical field of pressure sensors, and discloses a pressure sensor with a medium isolation measurement module. The pressure sensor sequentially comprises a protective cover, a first housing and a medium isolation module from top to bottom, wherein the medium isolation module comprises a base. According to the pressure sensor with the medium isolation measurement module, a first cavity is formed among the base, a metal piece and a diaphragm to isolate and package silicone oil; a pressure chip is isolated and packaged for protection to prevent direct contact with adetection medium, and corrosion is avoided; a buffer hollow cylinder and the diaphragm are isolated by a limiting circular ring, and accumulated liquid can be rapidly discharged in real time, so thatthe diaphragm is prevented from being damaged by freezing, and the output precision of the sensor can be ensured; the increase of the freezing volume of the detection medium at a low temperature is avoided, the change of the volume can be absorbed by the buffer hollow cylinder, and the purpose of high compatibility is achieved; and overload pressure generated by freezing of a urea solution can beresisted and freezing damage is prevented, and meanwhile, high-precision output is ensured.

Description

technical field [0001] The invention relates to the technical field of pressure sensors, in particular to a pressure sensor with a medium isolation measurement module. Background technique [0002] With the tightening of vehicle emission regulations in the country, automotive exhaust after-treatment SCR systems are gradually becoming popular in commercial vehicles. MEMS (micro-electromechanical system) pressure sensors, as important sensor components for SCR systems, are also facing severe technical challenges. [0003] The pressure sensor in the prior art can only withstand twice the overload pressure and three times the burst pressure, but when the urea solution used in the SCR system freezes at a low temperature, it can generate an overload pressure of 100 MPa, which is much higher than that of ordinary sensors. range, in the outdoor low-temperature freezing environment, the pressure sensor chip is easily damaged, and on the other hand, due to the weak corrosion character...

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Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a pressure sensor with a medium isolation measurement module, which has the advantages of strong medium compatibility, etc., and solves the problem of the pressure sensor chip in the prior art in an outdoor low-temperature freezing environment. It is very easy to be damaged, and on the other hand, due to the weak corrosion characteristics of urea solution, the durability of conventional pressure sensors is poor and the service life is short

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