Plastic Rotary Piston Pump Sealing for Solid-Liquid Mixtures
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Solution Overview
Problem
Current metering pumps, especially those made of plastic, struggle with accurately dispensing solid-liquid mixtures due to clogging and spoilage issues, as they are not designed to handle solid particles effectively, leading to inconsistent dosing and potential contamination.
Innovation Solution
The integration of multiple seals, including lateral sealing lips, scraping edges, and longitudinal skimming ribs on the rotor wing shoes and shafts, which are molded as one piece with the rotors, enhances sealing and prevents deposits, ensuring reliable operation and reduced air admission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metering pumps with rolling rotor blades are used, then liquid transport is achieved, but solid particles are crushed and deposits form reducing flow rate and causing clogging
Solution Approach 1:
The rotor blade is segmented into a working surface and a sealing edge. The sealing edge is specifically designed as a separate functional element that runs along the housing wall, preventing deposits from forming in the gap between rotor and housing while the working surface continues to transport liquid and solids effectively.
Solution Approach 2:
Different parts of the rotor blade are given different functions: the working surface is optimized for material transport while the sealing edge is optimized for preventing deposit formation. This local differentiation allows the pump to handle solid-liquid mixtures without clogging while maintaining high flow rates.
2Ease of manufacture
If disposable plastic pumps are used, then cost-effectiveness is improved, but sealing performance deteriorates leading to air admission and spoilage
Solution Approach 1:
The sealing edge is integrally molded with the rotor blade as a single piece, eliminating the need for separate sealing components. This integration maintains reliable sealing performance while keeping the pump design simple and cost-effective for disposable plastic construction.
Solution Approach 2:
The sealing edge automatically prevents air admission and deposit formation through its geometric design and positioning, without requiring additional active sealing mechanisms or maintenance. The structure itself provides the sealing function, reducing complexity and cost.
3Adaptability or versatility
If rotor blades with sufficient space between housing and blades are used, then solid material transport is improved, but smaller solid particles remain stuck on rotor blades and are completely crushed
Solution Approach 1:
The rotor blade design separates the transport function from the sealing function, allowing adequate space for solid particle transport while the sealing edge prevents crushed particles from adhering to the housing wall and forming deposits.
Solution Approach 2:
The sealing edge converts the potentially harmful effect of particle crushing into a beneficial sealing action, preventing crushed particles from forming deposits that would reduce flow rate and cause clogging.
Data Source
AI summary
The invention relates to a rotary piston pump for one-time use made of plastic for screwing onto a fastening nozzle on a tubular bag, having two rotors (10), which are coupled to each other via gear wheels (11) and which can be driven in opposition and which are mounted in a pump housing (5), which has suction nozzles (6) and outlet nozzles (7), wherein each rotor (10) has a rotor shaft (12), the rotor shaft ends (15) thereof being mounted in the walls (8, 4) of the pump housing (5), and the gear wheels are integrally molded to the rotor shafts, and wherein each rotor (10) has two rotor wing walls (13) arranged diametrically on the rotor shaft (12) which flare continuously outward and to each of the peripheral ends of which a partially cylindrical rotor wing shoe (14) is molded, wherein the rotor wing shoes (14) contact the cylindrical inside wall regions of the pump housing (5), on one side, and the rotor wing shafts (13) of the adjacent rotor (10) on the other, in a sliding and sealing matter, wherein seals are integrally molded on the rotor, wherein the seals serve to prevent the effects of air admission onto the content located in the tubular bag to as great an extent as possible.