精密超声波密度计研究.pdf

机床与液压
Dec.2014
Hydromechatronics Engineering
Vo.42No.24
DOI:10.3969/j.isn.1001-3881.2014.24.008
Study on the precision ultrasonic densimeter
Xing-hong ZHANG Iei QIU_, Xin CHEN, Tao HE, Shu-xiang LIU
Chongqing Key laboratory of Time-grating Sensing and Adanced Testing Technology, Chonging University of
Technology, Chongging 400054, China
Vehicle Engineering Department, Sichuan Engineering Technical College, Deyang 618000, China
Abstract: To settle some problems on the traditional density measurement instrument against ac
tual application, a high precision ultrasonic densimeter is designed on the basis of the ultrasonic
wave propagation characteristics. The high resolution and fast signal collection circuit and the dig
ital subdivision algorithms which are used to make the measurement of the ultrasonic wave propa
gation time reach nanosecond and ensure the measurement resolution of the ultrasonic densime
ter better than 0.000 01 x kg/m. The distributed measuring probes are installed oppositely at
the ektexine of the vessel which is contained the measured medium. The distributed structure de-
sign is helpful to improve the accuracy of the measurement result
Key words: Ultrasonic wave, Density measurements, Echo signal, Digital subdivision
cy and difficult maintenance; the ray densimeter can
1. Introduction
realize non-eontacl measurement. but also has the
disadvantage about radiation hazards 21
Density is one of physical quantities of material
In reeent years, with the rapid development of
properties. The density measurement embodies the the high technology, a new thought of the density
measurement level of our country and is widely used measurement is proposed based on the ultrasonic
in the field of technology, agriculture, industry and technology[ I. The ultrasonic technology can realize
our daily life 1
the density measurement with the non-contact and
Several kinds of densimeters are used in the in-continuity[ 4]. The ultrasonic density sensors have
dustry, such as vibration liquid densimeter, capaci- promising application prospects, which can complete
e liquid densimeter and ray density sensor, but in the dynamic measurement of density with high preci
the practical applicatior these traditional densimeter
sion[「5
all have some deficiencies. For examples. the vibra
tion Ilc
uid densimeter and the capacitive liquid den-2. The principle of ultrasonic densimeter
simeter have the characteristic of low cost and wide
measurement rang, but the low measurement accura
The density measurement by using the ultrasonic
technology is based on the relationship between the
Received. 2014-08-30
ultrasonic propagation characteristic and the media
Project supported by the Natural Science Foundation of
density. The ultrasonic wave propagation velocity
Chongqin(Grant No. cstc2012iia70004 and cstc2012
changes with the variation of media density when
IA40062), the National Natural science Foundation o
China(Grant No. 51275551), and the Graduate Inno-
propagating in the media. The media density can be
vation Fund of Chongqing University of Technology
measured indirectly through the propagation velocity
Grant No. YCX2013206)
measurement of the ultrasonic wave in the media
Xing-hong ZHANG, P