Diaphragm Pump Actuating Device for Constant Mass Flow Rate
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Solution Overview
Problem
Membrane pumps in medical technology face challenges in achieving high conveying accuracy at low flow rates, particularly in applications like citrate anticoagulation in dialysis, where maintaining a constant mass flow rate is crucial.
Innovation Solution
An actuating device with a base body, control fluid line, adjustment device, and control device that includes a control fluid valve, working fluid valve, and pressure sensors to precisely control the membrane pump, ensuring accurate fluid metering by influencing the cross-section of fluid lines and using an observer algorithm to maintain a constant mass flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane pumps are used for conveying medical liquids, then the drive unit is separated from the fluid by a membrane, but high conveying accuracy at low flow rates cannot be achieved
Solution Approach 1:
The patent implements feedback control by using pressure sensors to detect the actual pressure in the pump chamber and comparing it with a reference pressure curve. The control device adjusts the control fluid supply based on the deviation between actual and reference pressure, ensuring accurate fluid delivery even at low flow rates where precision is critical.
Solution Approach 2:
The patent changes the physical parameters of the control system by using pressure-controlled valves regulated by pressure sensors and control fluid lines. The system dynamically adjusts pressure parameters to maintain constant mass flow rate, enabling high conveying accuracy at low flow rates through precise parameter control rather than mechanical adjustments.
2Reliability
If the mass flow rate of fluid is to be kept constant, then precise control mechanisms are required, but the device complexity increases
Solution Approach 1:
The control device serves multiple functions: it regulates control fluid valves, adjusts working fluid valves, processes sensor signals, generates reference pressure curves, and performs feedback control all within a single integrated unit. This multi-functionality reduces overall system complexity while maintaining constant mass flow rate through centralized control rather than multiple separate control mechanisms.
Solution Approach 2:
The system performs self-regulation through the feedback loop where pressure sensors automatically detect deviations and the control device autonomously adjusts valve positions to maintain constant mass flow rate. The observer algorithm within the control device self-corrects flow variations without external intervention, simplifying the control mechanism while ensuring reliability.
3Manufacturing precision
If conveying accuracy is improved at low flow rates, then the control system must be highly precise, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical precision mechanisms with a pressure-controlled system using control fluid lines and electronically regulated valves. Instead of relying on mechanical tolerances for accurate fluid metering, the system uses pressure feedback and electronic control to achieve high conveying accuracy, simplifying manufacturing while maintaining precision.
Solution Approach 2:
The patent introduces control fluid as an intermediary medium between the control device and the pump chamber. The control fluid transmits control signals to regulate the membrane pump's operation, enabling precise fluid metering through pressure control rather than direct mechanical adjustment, thereby reducing manufacturing complexity while improving metering accuracy.
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
The actuating device enables reliable and accurate fluid conveyance with a constant mass flow rate, even at low flow rates, enhancing the performance of membrane pumps in medical applications such as dialysis devices.
Implementation Method 1
a control fluid valve which is designed to influence a cross section of the control fluid line
Implementation Method 2
a working fluid valve which is designed to influence a cross section of a working fluid line
Implementation Method 3
pressure sensors to precisely control the membrane pump, ensuring accurate fluid metering
Implementation Method 4
By moving the membrane, a volume of the pump chamber is changed so that, provided in addition that the suction channel and the pressure channel are blocked and released cyclically, a mass flow rate for the fluid can be generated
Data Source
AI summary
An actuating device mechanically controls a membrane pump device. The device includes a base body having a mounting face for a membrane pump device and through which a control fluid line passes that extends from a control fluid port to a control fluid opening that opens at the mounting face. A control fluid valve arranged in the control fluid line influences a cross-section of the control fluid line and has an adjustment device that has a fluid actuator arranged on the mounting face. A working fluid valve influences a cross-section of a working fluid line that passes through the base body. The control fluid valve and the working fluid valve are electrically connected to a control device that electrically controls the control fluid valve and the working fluid valve. Moreover, a membrane pump is provided that has an actuating device and a membrane pump device.