Miniaturized Rotary Pump with Radial Fluid Ports
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Solution Overview
Problem
Existing rotary displacement pumps have large radial dimensions, making them unsuitable for miniaturization and integration into compact medical devices like heart prostheses, and they face issues with cavitation and turbulent fluid displacement.
Innovation Solution
The pump design incorporates a removable wall with a bearing, a hollow motor shaft, and a tie rod that allows the inner gear to be easily fitted and removed, with a reduced number of teeth on the gears to minimize radial dimensions and facilitate lubrication, and a radial fluid inlet and outlet extending across the outer gear for improved fluid handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the pump is miniaturized by reducing the number of gear teeth, then the radial dimensions are reduced, but the fluid displacement efficiency decreases leading to cavitation and turbulent losses
Solution Approach 1:
The pump chamber is divided into multiple sealed compartments by the gear teeth and casing walls. This segmentation allows each tooth space to function as an independent pumping unit, enabling efficient fluid displacement even with fewer teeth. The segmentation principle resolves the contradiction by maintaining functional efficiency through proper compartmentalization rather than relying on tooth quantity.
Solution Approach 2:
The invention extends the radial fluid inlet and outlet from the traditional side-mounted configuration to span the entire length of the outer gear perpendicularly. This dimensional change in fluid pathway configuration allows for improved fluid intake and discharge efficiency without increasing the number of gear teeth, thus reducing radial dimensions while maintaining displacement efficiency.
2Ease of manufacture
If the inner gear is made dismantleable for easy assembly, then the ease of manufacture improves, but the structural integrity and sealing performance may deteriorate
Solution Approach 1:
The outer gear is divided into separate modular components (inner and outer sections) that can be assembled and disassembled independently. This segmentation enables easy manufacturing and assembly while the precision-machined mating surfaces and sealing interfaces between segments maintain reliable sealing performance, resolving the contradiction between ease of manufacture and sealing integrity.
Solution Approach 2:
Sealing elements or gaskets are introduced as intermediary components at the interfaces between dismantleable gear sections. These intermediaries ensure that the joints between modular components maintain adequate sealing performance, allowing the gear to be easily assembled and disassembled without compromising reliability.
3Device complexity
If the motor shaft is made hollow to pass the tie rod, then the device complexity is reduced, but the motor shaft manufacturing difficulty increases
Solution Approach 1:
The motor shaft and tie rod functions are merged into a single hollow shaft component. This consolidation eliminates the need for separate tie rod and shaft components, reducing overall structural complexity. While the hollow shaft requires more advanced manufacturing, the integration simplifies the overall assembly and reduces the number of parts, resolving the contradiction at the system level.
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 design enables the miniaturization of the rotary displacement pump while preventing cavitation and turbulent losses, allowing for its use in compact medical applications like heart prostheses with reversible output.
Implementation Method 1
said tie rod may itself be hollow so that said liquid can enter it, and the side wall of said tie rod may be pierced with orifices. In this way, said bearings of the inner gear, carried by said tie rod, can be lubricated with said hydraulic liquid.
Implementation Method 2
In order to avoid the risks of cavitation and turbulent losses in the fluid displaced by the pump, it is advantageous for said radial fluid inlet and/or for said radial fluid outlet to extend from one end plate of said outer gear to the other.
Data Source
AI summary
According to the invention the rotary pump consists of an external gear (13) with internal teeth (16) in the form of a squirrel cage, and an internal gear (9), housed in an off-centre manner in the interior of said external gear (13) and fitted with external teeth (9D) intermeshing with said internal teeth (16) and consisting of a number of inferior teeth of a unit with the number of teeth of the later. The rotation means of said external teeth (13) comprise at least a bearing (11, 12) centrally laid out in a flange end (14,15) of said aforementioned external gear (13) and the aforementioned external gear (13) is at least partly dismantled in order to introduce said internal gear (9).