Reciprocation Pump Sub-chambers Reduce Pulsation
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Solution Overview
Problem
Reciprocation pumps used in dialysis and other applications face challenges in reducing pulsation caused by the reciprocating motion, leading to increased internal pressure in piping and potential damage to equipment when supplying large volumes of fluid, due to the compressibility of liquids and flow resistance.
Innovation Solution
Incorporating supply and waste liquid-side sub-pumping chambers that are interlocked with the main pumping chambers to vary their volume reversely, allowing the reciprocating motion to supply fluid through both chambers, thereby reducing pulsation and eliminating the need for separate sealing means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate of dialysate is increased to supply large amount of liquid, then productivity is improved, but internal pressure within piping increases causing harmful factors
Solution Approach 1:
The pump is divided into multiple pumping chambers (first pumping chamber and second pumping chamber) that operate in sequence. Each chamber handles a portion of the total flow, allowing high flow rate delivery while distributing pressure peaks across separate chambers rather than concentrating them in a single chamber.
2Ease of operation
If reciprocating motion is used to pump liquid, then ease of operation is improved, but pulsation is generated causing harmful factors
Solution Approach 1:
The pump employs periodic reciprocating motion of the plunger that cycles through distinct phases: suction phase, transition phase, and discharge phase. This periodic action creates controlled pulsation patterns that are manageable and can be dampened, while still maintaining the simplicity of reciprocating operation.
Solution Approach 2:
A transition phase is introduced between the suction phase and discharge phase where the plunger moves without actively pumping. This preliminary action prepares the system by equalizing pressure and positioning the plunger, thereby reducing sudden pressure spikes and pulsation when transitioning to the discharge phase.
3Object-generated harmful factors
If mixing chamber volume is increased to reduce pulsation, then pulsation is reduced, but device complexity increases
Solution Approach 1:
Instead of using a single large mixing chamber, the pump is segmented into multiple smaller pumping chambers that inherently reduce pulsation through distributed pumping action. This segmentation achieves pulsation reduction without requiring a large-volume mixing chamber, thereby avoiding increased device complexity.
4Reliability
If check valves are installed in each pumping chamber, then reliability is improved, but device complexity increases
Solution Approach 1:
The discharge valves of the first and second pumping chambers are merged into a common discharge passage. This consolidation reduces the number of separate valve components while maintaining reliable one-way flow control, as the shared discharge valve handles the combined output from both chambers.
Data Source
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AI summary
One object of the present invention is to provide a reciprocation pump which can reduce the pulsation of the liquid and waste liquid caused by the reciprocating motion of the reciprocation pump and also to provide a dialysis apparatus equipped with such a reciprocation pump. According to the present invention, there is provided a reciprocation pump characterized in that the reciprocation pump comprises a supply liquid-side sub-pumping chamber for containing and sending out liquid adapted to be communicated with the supply liquid-side pumping chamber and interlocked with the reciprocation means to vary its volume reversely to that of the volume variation of the supply liquid-side pumping chamber; and a waste liquid-side sub-pumping chamber for containing and sending out liquid adapted to be communicated with the waste liquid-side pumping chamber and interlocked with the reciprocation means to vary its volume reversely to that of the volume variation of the waste liquid-side pumping chamber; and that the reciprocating motion of the reciprocation means enables the liquid to be supplied to the objective apparatus through the supply liquid-side pumping chamber and the supply liquid-side sub-pumping chamber as well as enables the waste liquid from the objective apparatus to be discharged to the outside through the waste liquid-side pumping chamber and the waste liquid-side sub-pumping chamber.