静脉输液液位自动检测系统的研究

【作者】 张克平；

【导师】 张爱华；

【作者基本信息】 兰州理工大学 ， 控制理论与控制工程， 2004， 硕士

【摘要】 医学静脉输液是临床医学中一个重要的治疗手段，在输液过程中，若药液接近滴完或因某种事故使输液速度过高或过低时，都要医务人员及时处理。目前由于没有有效、经济的自动检测装置，在输液时病人需要专人监护，加重了病人的思想负担和护理人员的劳动负担，也不利于病区的综合管理，为此我们研制医用输液液位和输液速度实时检测系统，该系统可以自动检测输液液位，并能将各床位液位和输液速度信号传送至护办室，在护办室对多个病房各个床位的输液情况进行巡回检测和显示。当液位低于设定下限值、输液速度过高或过低时，在护办室和相应床位处都能发出声光报警，提醒护理人员及时处理。为实现输液液位的自动、准确和非接触测量，设计一种变介电常数型电容式液位传感器。通过对不同宽度电极下传感器电容与对应液位的实验数据分析，发现液位处于输液瓶上部圆柱段时电容与液位高度之间有很好的线性关系，而在下部呈现非线性；传感器灵敏度随电极宽度的增加而近似线性提高。同时发现传感器灵敏度与液位下降速度相关。进而建立了传感器数学模型，分析影响传感器灵敏度的因素和机理。研究结果表明，以范德华力附着在瓶壁内侧的吸附水在电场作用下容易被极化，会引起其介电常数超常增大；瓶壁内侧的吸附水对传感器的灵敏度有直接影响。从而为传感器的正确设计与测量数据的修正提供了理论依据。本检测装置主要由电容式传感器、本地信号转换和报警模块、集中采样模块(从站)等部分组成，其中本地模块亦可单独使用。通过传感器理论设计、制作及具体电路设计和调试，发现该检测装置能基本满足实际需要，从而初步开发出一套静脉输液液位检测系统。更多还原

【Abstract】 Medical infusion is an important treatment in clinic. During the infusion, medical personnel have to deal with the business in time when the infusion fluid is dripping up and when the infusion speed is much slower or faster. Because of the absence of the automatically measuring settings, special medical person has to ward them. This aggravates the patient’s mental burden and the nursing persons’ working burden. This also handicaps the synthesis management of the ward. Thus, the system is developed to measure infusion liquid level and infusion speed. The system automatically transports the detecting signal to the nursing office. In it the infusing situation of every bed in every sickroom is displayed. When the infusion liquid level is under the given lower limit and the infusion speed is much faster or lower, the alarm will be made in nursing office and corresponding bed to remind the paramedic to deal with it.To measure the medical infusion liquid level automatically and accurately without contact, a variable- dielectric-constant capacitive sensor is designed. The experimental data is obtained with the use of electrodes of different width. By analyzing the correlation between them, it is found that the sensitivity affected by the speed of infusion. The model of the sensor is presented and then the affecting factors and the mechanism on the sensitivity are discussed. It is showed that the water absorbed on the inside wall by molecular force is easily polarized, making the dielectric constant abnormally increase, which make water absorbed have significant effect on the sensitivity. Theoretical foundation for the designation of sensor and modification of the measured data is providedThis measuring setting consists of capacitance sensor, local measuring and alarming block, central sampling block etc. The local measuring and alarming block can be used singly.Through theoretically designing and fabricating the capacitance sensor, circuit designing and debugging, it found that the measuring setting can satisfy practical demands. Based on this a suit of infusion-liquid-level-measuring system is developed.更多还原