Pump Assembly Agitation with Spiral Flow Separation
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Solution Overview
Problem
Chilled beverage dispensers with 'holeless' bowls face challenges in sanitation due to complex heat exchanger designs and often cause turbulent flow and foaming when using bladed impellers, especially at low beverage levels.
Innovation Solution
A pump assembly with a bladed impeller positioned within the dispenser bowl, magnetically coupled to a rotating magnet outside, featuring a dome-shaped inner and outer pump shell design that separates inflow and outflow streams along the bottom wall, minimizing turbulent flow and foaming by directing beverage flow spirally through the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bladed impeller is used to agitate the beverage, then effective mixing is achieved, but turbulent flow and foaming occur especially at low beverage levels
Solution Approach 1:
The pump assembly is segmented into an inner pump shell and an outer pump shell, creating separate flow paths. The inner shell handles the primary agitation function while the outer shell provides a containment structure that directs flow, separating the mixing action from the discharge path to reduce turbulence and foaming.
Solution Approach 2:
Instead of drawing beverage from the top and discharging at the bottom (which creates air intake and foaming), the pump assembly is configured to draw beverage from the bottom through the inner pump shell and discharge through the outer pump shell, reversing the conventional flow pattern to minimize air entrainment and turbulent surface flow.
2Temperature
If a heat exchanger bank with tubes submerged in the beverage is used, then effective heat transfer is achieved, but sanitation becomes difficult due to complex internal surfaces
Solution Approach 1:
The heat exchanger tubes are extracted from the beverage chamber and relocated to the bottom wall of the dispenser bowl. This allows the tubes to be positioned in a location that is accessible for cleaning while still maintaining thermal contact with the beverage through the bowl wall, solving the sanitation difficulty associated with submerged tube banks.
Solution Approach 2:
The bottom wall of the dispenser bowl acts as an intermediary heat conductor, transferring heat from the beverage to the cooling medium flowing through the heat exchanger tubes. This intermediary structure allows heat transfer without requiring direct contact between the tubes and beverage, simplifying sanitation.
3Ease of manufacture
If a holeless dispenser bowl design is used, then sanitation is improved by allowing easy removal of the bowl, but the heat exchanger must be positioned externally requiring complex heat transfer through the bowl wall
Solution Approach 1:
The bottom wall of the dispenser bowl serves multiple functions: it acts as a structural support, a thermal transfer surface for the heat exchanger, and a mounting surface for the pump assembly. This multi-functionality simplifies the overall design by eliminating the need for separate heat transfer mechanisms while maintaining the holeless design benefits.
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 design ensures effective agitation of beverages while reducing turbulent flow and foaming, maintaining sanitation and efficiency by allowing for easy cleaning of the dispenser bowl and minimizing air intake during operation.
Implementation Method 1
an impeller which rotates about a substantially vertical axis
Implementation Method 2
magnetically coupled to and driven by a rotating magnet exterior to the bowl
Implementation Method 3
directing beverage flow spirally through the assembly
Data Source
AI summary
A pump assembly for a chilled beverage dispenser includes an axle oriented in a substantially vertical orientation at a predetermined location along a bottom wall surface of the dispenser bowl; an impeller which rotates about an axis defined by the axle; an inner pump shell that fits over the axle and defines an internal cavity for enclosing the impeller without impeding rotation of the impeller; and an outer pump shell that fits over and engages the lower pump shell, with a cavity being defined and maintained between the inner pump shell and the outer pump shell. As the bladed impeller rotates, beverage is drawn into the pump assembly along the bottom wall surface of the dispenser bowl, and is also discharged along the bottom wall surface of the dispenser bowl, thus providing maximum agitation of the beverage.