Infusion Pump Calibration via Actuator Position Feedback
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Solution Overview
Problem
Peristaltic infusion pumps face inaccuracies in infusion rate due to manufacturing tolerances affecting the shape and real volume of the pump channel, leading to deviations from the intended nominal stroke volume.
Innovation Solution
A method to calibrate the infusion device by measuring the vertical position of the actuation device during a pump cycle, calculating a characteristic value from the difference between the measured and nominal profiles, and using this value to correct or check the actual stroke volume, thereby adjusting operational parameters for accurate infusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pump device is fabricated using standard manufacturing processes, then production efficiency and cost are improved, but manufacturing precision deteriorates due to tolerances in pump channel shape
Solution Approach 1:
The patent applies preliminary action by measuring the vertical position of the actuation device during a pump cycle before using the pump device for its intended infusion function. This calibration measurement is performed in advance to detect deviations in the pump channel shape caused by manufacturing tolerances. The measured profile is then compared to a nominal profile to calculate a characteristic value that compensates for these deviations, thereby correcting the stroke volume parameter before actual infusion operations begin.
2Device complexity
If the nominal stroke volume is used for controlling infusion operations, then device complexity is reduced, but reliability deteriorates due to inaccurate infusion rates
Solution Approach 1:
The patent implements feedback by measuring the actual vertical position profile of the actuation device during pump operation and comparing it to the expected nominal profile. This comparison provides feedback information about deviations in the pump channel shape. Based on this feedback, a characteristic value is calculated that represents the actual stroke volume deviation. This feedback mechanism allows the system to automatically compensate for manufacturing tolerances and achieve accurate infusion rates without requiring complex manual calibration procedures.
3Manufacturing precision
If manufacturing tolerances are tightened to improve pump channel precision, then manufacturing precision is improved, but production cost and complexity increase
Solution Approach 1:
The patent applies parameter changes by measuring the vertical position of the actuation device during pump operation to detect changes in the pump channel shape caused by manufacturing tolerances. Instead of trying to prevent these variations through tighter manufacturing controls, the system measures the actual geometric parameters (vertical position profile) and uses this information to calculate a corrected stroke volume parameter. This approach allows standard manufacturing processes to be used while still achieving accurate infusion rates through parameter compensation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for reliable correction of actual stroke volume deviations, ensuring accurate infusion rates by accounting for shape tolerances in the pump channel, thereby improving the precision of infusion operations.
Implementation Method 1
measuring the vertical position of the actuation device during a pump cycle to obtain a measured profile
Implementation Method 2
a pump actuation mechanism acting onto the pump device in a peristaltic fashion in order to pump a fluid through the pump device
Data Source
Figure 1
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Figure 4
AI summary
An infusion device comprises a pump device (1) having a housing part (103) and a flexible wall section (120) together forming a pump channel (121) through which a fluid is to be pumped, wherein the pump channel (121) has a first end (120A) as inlet for a fluid and a second end (120B) as outlet for a fluid, wherein the pump channel (121) extends along a channel length (C) between the first end (120A) and the second end (120B). The infusion device further comprises a pump actuation mechanism (2) having an actuation device (20) for acting onto the flexible wall section (120) along the channel length (C) of the pump channel (121) for locally depressing the flexible wall section (120) in a vertical direction (Z) in order to pump a fluid through the pump channel (121), the actuation device (20) being displaceable with respect to a housing section (22) of the pump actuation mechanism (2) along the vertical direction (Z). A control device (25) controls the operation of the pump actuation mechanism (2), wherein, for pumping a fluid through the pump channel (121), the actuation device (20) is actuated to depress the flexible wall section (120) at a depression location (A), wherein the depression location (A) during one pump cycle moves along the channel length (C) of the pump channel (121). Herein, for calibrating the infusion device, the position of the actuation device (20) along the vertical direction (Z) during one pump cycle is measured to obtain a measured profile, a difference between the measured profile and a nominal profile prestored in the control device (25) is formed to obtain a difference profile, and from the difference profile a characteristic value for correcting and/or checking the pump operation of the infusion device is calculated.