Liquid Gear Pump Using PPS Gears for Hot Beverage Dispensing
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Solution Overview
Problem
Gear pumps in automatic beverage dispensers face issues with gear expansion and wear when handling hot liquids, leading to inefficiency and potential jamming, while also needing to meet food safety standards.
Innovation Solution
The use of polyphenylene sulfide (PPS) and glass fiber materials for the driving and idle gears, along with a ceramic idle shaft and specific housing materials, prevents expansion and enhances mechanical strength, ensuring high temperature resistance, wear resistance, and compliance with food safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gears are made of conventional materials, then the pump operates efficiently with cold or warm liquids, but the gears expand excessively when handling hot liquids leading to wear or jamming
Solution Approach 1:
The patent changes the material parameter of the gears from conventional materials to polyphenylene sulfide (PPS), which has a specific property of minimal thermal expansion. This parameter change allows the gears to maintain dimensional stability across a wide temperature range, resolving the contradiction between reliability under temperature variation and pump efficiency.
Solution Approach 2:
The patent employs composite material construction for the gears using polyphenylene sulfide as the base material. This composite material provides both the thermal stability needed for hot liquid handling and the mechanical strength required for efficient pumping operation, simultaneously addressing both contradictory requirements.
2Reliability
If the gears are sized to allow for expansion in hot liquids, then gear wear and jamming are avoided, but the pump does not operate efficiently with cold or warm liquids
Solution Approach 1:
Instead of changing the gear size, the patent changes the material parameter (thermal expansion coefficient) of the gears by using polyphenylene sulfide. This allows the gears to maintain consistent dimensional properties across temperature variations, ensuring reliable gear engagement without compromising pump efficiency for any liquid temperature.
3Ease of manufacture
If conventional materials are used for gears in direct contact with liquid, then manufacturing is easier, but food safety requirements may not be met
Solution Approach 1:
The patent specifies polyphenylene sulfide (PPS) as the gear material, which is a food-safe composite material. This material can be manufactured using conventional processes while meeting food safety requirements for direct liquid contact, thus resolving the contradiction between ease of manufacture and food safety compliance.
Data Source
AI summary
A liquid gear pump includes a gear pump assembly and an electric motor with an motor shaft. The gear pump assembly includes a pump housing which defines a pump chamber, an inlet and an outlet which are in fluid communication with the pump chamber, and a driving gear and an idle gear which are received in the pump chamber. The driving gear is driven by the motor shaft. The idle gear is supported on an idle shaft and engaged with the driving gear. The driving gear and the idle gear are made of a material with a main component of PPS.