System structure and working principle of medical infusion pump

The infusion pump system is mainly composed of a microcomputer system, a pump device, a monitoring device, an alarm device, and an input and display device.

Infusion pump system
The microcomputer system is the "brain" of the whole system, which controls and manages the whole system intelligently, and processes the detection signals. Generally, a single-chip microcomputer system is used. For example, the infusion pump adopts a highly integrated 32-bit ARMCPU system to fully control the infusion process, and uses dual CPUs to ensure the safety of the system.

The pump device is the "heart" of the whole system, and is the power source for liquid delivery. Medical infusion pumps generally use finger-shaped peristaltic pumps as the power source. The finger-shaped peristaltic pump uses the rotation of the roller to squeeze a certain part of the infusion pump pipeline to generate peristalsis, thereby pushing the liquid to flow forward. Finger peristaltic pump has the characteristics of small size, light weight, accurate quantitative and convenient loading and unloading of infusion tube, and is the most widely used. This kind of pump has a camshaft, there are multiple cams on the camshaft, the motion laws of these cams differ by a certain angle, and each cam is connected with a finger-shaped slider.

When working, the stepper motor drives the camshaft to rotate, so that the slider reciprocates up and down according to a certain sequence and motion law, and squeezes the intravenous infusion tube in sequence like a wave, so that the liquid in the infusion tube flows directionally at a certain speed. The finger peristaltic pump is more accurate, and can control the total amount of infusion and the infusion speed in a wide range; when the number of "finger" exceeds 8 (usually 12), the linearity of the pump is good, and it is not easy to generate pulsation during infusion, which makes the infusion pump The safety and stability monitoring device is mainly composed of a variety of sensors. The infusion pump is equipped with an infrared drop count sensor, a pressure sensor and an ultrasonic bubble sensor, etc. detection.


The alarm system is that after the signal sensed by the sensor is processed by the microcomputer, the alarm control signal is obtained, and then the alarm device responds to attract people's attention and carry out correct processing at the same time. With photoelectric alarm and sound alarm function, it can alarm for abnormal situations such as power failure, pump door not closed, low temperature, completion of infusion, battery underpressure, pipeline blockage and bubbles in the pipeline during the infusion process. The input part of the input and display device is responsible for setting various parameters of the infusion, such as infusion volume and infusion speed. The display part is responsible for displaying each parameter and the current working status.