Pressure Sensor Membrane Recoupling in Dialysis
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Solution Overview
Problem
Pressure measuring devices in extracorporeal circuits, such as those used in dialysis, face challenges in maintaining reliable pressure detection over extended periods due to potential membrane detachment from the pressure sensor, especially under negative pressure conditions, leading to inaccurate or failed measurements.
Innovation Solution
The method involves periodically increasing pressure in the measuring chamber to slightly curve the membrane outward, allowing for reliable recoupling with the pressure sensor at predetermined intervals or upon error detection, ensuring a consistent and accurate connection by generating overpressure to prevent inward deformation during reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressure measuring device operates continuously for extended periods, then productivity is improved, but the membrane may detach from the pressure sensor leading to measurement failures
Solution Approach 1:
The patent implements periodic recoupling cycles where the membrane is separated from and reconnected to the pressure sensor at predetermined time intervals. This periodic action prevents permanent detachment by resetting the adhesive bond, thereby maintaining measurement reliability during continuous operation without interrupting the overall treatment process.
Solution Approach 2:
The patent applies preliminary action by generating overpressure in the measuring chamber before recoupling the membrane to the pressure sensor. This overpressure ensures the membrane is properly positioned and firmly attached before measurement resumes, preventing immediate detachment and ensuring reliable measurements from the start of each recoupling cycle.
2Measurement precision
If the membrane is recoupled to the pressure sensor under negative pressure, then the membrane may be pulled inward causing measurement errors, but increasing pressure requires additional system complexity
Solution Approach 1:
The patent employs self-service by utilizing the existing blood pump already present in the extracorporeal circuit to generate the necessary overpressure for recoupling. The pump is temporarily operated in reverse to create positive pressure in the measuring chamber, eliminating the need for separate pressure generation devices and minimizing additional system complexity.
Solution Approach 2:
The patent applies parameter changes by temporarily altering the pressure parameter in the measuring chamber from negative to positive during recoupling operations. This pressure parameter change ensures the membrane curves outward for proper alignment and firm attachment to the pressure sensor, thereby guaranteeing measurement precision without requiring complex positioning mechanisms.
3Reliability
If the membrane remains attached to the pressure sensor throughout continuous operation, then measurement continuity is maintained, but adhesive degradation occurs leading to detachment
Solution Approach 1:
The patent implements periodic recoupling cycles where the membrane is deliberately separated from and reconnected to the pressure sensor at predetermined time intervals. This periodic action refreshes the adhesive bond before it degrades completely, maintaining measurement reliability over extended periods by preventing permanent detachment while allowing the adhesive to recover during each recoupling cycle.
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 approach ensures reliable pressure measurements over long periods by maintaining a good connection between the membrane and pressure sensor, preventing measurement failures and drifts, and can be implemented quickly and safely.
Implementation Method 1
Increasing the pressure in the measuring chamber to a pressure value at which the membrane is at least slightly curved outwards relative to the measuring chamber when it is not connected to the pressure sensor
Implementation Method 2
a pressure sensor which is in communication for the purpose of pressure measurement with the membrane
Data Source
Figure 1a~1e
Figure 2
AI summary
The present invention relates to a method for operating a pressure measuring unit for measuring the pressure in a system through which fluid flows, particularly in an extracorporal cycle of a medical device, wherein the pressure measuring unit has a measuring chamber limited by a flexible membrane, said chamber having fluid flowing therethrough or being filled with fluid during the operation of the system, and a pressure sensor which is in contact with the membrane for the purpose of measuring the pressure, wherein the method comprises the following steps requiring no intervention of personnel: a. increasing the pressure in the measuring chamber (12) to a pressure value at which the membrane (13) is at least slightly bulged outward relative to the measuring chamber (12) in the state where the membrane is not in contact with the pressure sensor (14), or determining such a pressure value, b. separating the membrane (13) of the measuring chamber (12) from the pressure sensor (14), c. bringing the membrane (13) of the measuring chamber (12) and the pressure sensor (14) together such that the membrane (13) of the measuring chamber (12) abuts the pressure sensor (14), and d. repeating steps a. to c. in predetermined time intervals, and/or upon the occurrence of an error.