Design and fabrication of a plunger type infusion pump having accurately controlled flow rate

• Main Authors: Tsung-Yung Chen, 陳宗雍
• Other Authors: 王國禎
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/41490119135730569987

碩士 === 國立中興大學 === 機械工程學系所 === 95 === A plunger pump possesses the characteristics of high pressure, low flow rate, and high sensitivity. The flow rate can be accurately manipulated by only controlling the movement of the piston without an additional flow meter. For the applications in continuous flow delivering or more than one chamber delivering, it is desired to have a reciprocating scheme with more than two plungers. In this research, a portable and simple three-plunger reciprocating pump system having accurately controlled flow rate has been proposed. The proposed flow control system consists of three plungers to continuously deliver the sample, a stepping motor to drive the crank shafts of the plungers, an 8051 single chip to control the angular velocity of the stepping motor, and a 16×2 LCD panel with to a 6-key keyboard interface to display the working message. To maintain a steady flow rate, the traveling speed of a plunger under constant crank shaft rotation was analyzed to find out the variations of the flow rate at the outlet. The adjusting index for the flow rate with respect to a certain angular position of the crank shaft was accordingly calculated. Based on the calculated adjusting indexes, the pulse-generating program for the stepping motor in the 8051 single chip was than modified to on-line control the driving speed of the stepping motor. To verify the characteristics of the proposed system, a simple flow rate measuring device by sensing the dropping induced vibrations of continuous droplets was developed. Experimental results demonstrate that the proposed simple three-plunger reciprocating pump system can precisely maintain a relatively small flow rate.