Resonant tuning fork liquid density sensor with piezoelectric actuation and piezoelectric detection

Abstract

The invention discloses a resonant tuning fork liquid density sensor with piezoelectric actuation and piezoelectric detection, comprising a tuning fork body, a clamped body, a piezoelectric actuator, a piezoelectric vibration pickup, and a temperature sensor, wherein, the piezoelectric actuator and the piezoelectric vibration pickup are arranged on the clamped body, the generated alternating force is transmitted to the tuning fork body by the piezoelectric actuator to let the tuning fork body produce simple harmonic vibration with intrinsic frequency itself; when immersing the tuning fork body in a liquid under test, the additional mass of the tuning fork body changes so as to let the vibration frequency of the tuning fork body change; by picking up the vibration signal with the piezoelectric vibration pickup, the detection of the vibration frequency of the tuning fork body is realized; because the vibration frequency of the tuning fork body is a monotone function of the liquid density, thus the real-time on-line detection of the liquid density is realized; and the temperature sensor is arranged on the clamped body for real-time detection of the temperature of the liquid under test, and is used for compensating the variation of the elastic modulus of the tuning fork body. According to the invention, the high precision on-line detection of densities of various liquids at different temperature can be realized.

Description

technical field [0001] The invention relates to a resonant tuning fork liquid density sensor with piezoelectric excitation and piezoelectric detection. It is a high-precision resonant quasi-digital sensor, which belongs to the field of test and measurement instruments and is used for high-precision online measurement of liquid density. The resonant element is Tuning forks. Background technique [0002] Density is an important physical property of liquids. Measuring liquid density is one of the important means to achieve product quality control in many industries such as medicine, food, petrochemical and so on. Therefore, the measurement of liquid density is of great significance to enterprises. Traditional liquid density measurement methods, such as balance weighing method, density bottle method, float meter method, etc. These methods are mainly manual operation and manual reading. Therefore, it can only be used in discontinuous measurement occasions, and cannot convert ph...

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Problems solved by technology

Among them, the vibrating string method has a complex structure, is easily affected by the mechanical vibration of the environment and liquid flow, and has low precision; the vibrating tube method is more commonly used, but its flow rate is small, the mode shape is asymmetrical, and the vibration frequency is not stable enough; the vibrating membrane method The work is not easy to be stable and the reliability is poor; the vibrating cylinder method has high requirements on the manufacturing process, the uneven wall thickness of the vibrating cylinder will easily make the mode shape asymmetrical, the vibration frequency is unstable, and the viscosity of the liquid will affect the frequency of the vibrating cylinder

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