Helical Stirrer Scrapers for Cleanable Ice Cream Freezing Cylinders

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Solution Overview

Problem

Existing ice cream machines face issues with ice buildup on the stirrer and cylinder walls, leading to poor ice cream quality and bacterial contamination due to complex and difficult-to-clean stirrer designs.

Innovation Solution

A stirrer with helical scrapers mounted on a shaft, featuring interchangeable plastic scraping members with a fixed angle of incidence, allowing for efficient scraping, easy cleaning, and uniform mixing, while reducing friction and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the stirrer is equipped with integral scrapers to prevent ice layer formation on the cylinder wall, then the quality of the finished ice cream is improved, but the structure of the stirrer becomes very complex and difficult to clean

Engineering Contradiction:
Improvesmoothness of ice creamVSAvoidcomplexity of stirrer structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The stirrer is divided into separate components: a central shaft and interchangeable scraping members that can be independently removed and cleaned. This segmentation simplifies the overall structure while maintaining the ice-scraping function, allowing each component to be cleaned separately without disassembling the entire stirrer assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The scraping function is extracted from the main stirrer body and implemented as separate, removable scraping members. These members can be taken out for cleaning and maintenance without affecting the core mixing mechanism, thereby reducing the permanent complexity of the stirrer structure while preserving the ice-prevention capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If the stirrer operates for very long cycles without full immersion, then productivity is improved, but ice cream or ice builds up on the stirrer and harbors bacteria

Engineering Contradiction:
Improveoperating cycle lengthVSAvoidhygiene safety of ice cream
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The scraping members are designed as inexpensive, easily replaceable components that can be quickly removed and cleaned or replaced between production cycles. This allows for frequent hygiene maintenance without disrupting overall productivity, ensuring bacterial contamination is prevented while maintaining long operating cycles.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The design facilitates easy discarding of contaminated scraping members and their recovery through simple cleaning or replacement. The interchangeable nature of these members allows rapid recovery of the hygienic function without requiring complex dismantling or lengthy maintenance procedures.

Inventive Principle:
Principle #34Discarding and recovering

3Manufacturing precision

If prior art stirrers with springs and elastic elements are used for mounting scrapers, then the scraping function is achieved, but the system is awkward to dismantle and maintenance is lengthy

Engineering Contradiction:
Improvescraping effectivenessVSAvoidease of dismantling and maintenance
Core Design Contradiction:
Manufacturing precisionVSEase of repair

Solution Approach 1:

The mounting system is segmented into simple, tool-free connection mechanisms such as snap-fits, clips, or bayonet mounts. This allows the scraping members to be quickly detached and reattached without requiring springs, elastic elements, or specialized tools, dramatically simplifying maintenance while preserving scraping effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection mechanism parameters are changed from complex elastic-spring systems to simpler geometric interlocking systems. This parameter change maintains the functional requirements for secure mounting during operation while enabling rapid dismantling for maintenance through simple manual manipulation.

Inventive Principle:
Principle #35Parameter changes

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 stirrer ensures quick and thorough cleaning, maintains ice cream quality, and prevents bacterial contamination by facilitating easy maintenance and ensuring continuous scraping action without gaps for bacterial growth.

Implementation Method 1

a plurality of helical scrapers (7) extending around said axis of rotation (A)... operate on a cylindrical inside wall (10) of said mixing and freezing unit (2) to scrape the wall (10)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a power-driven stirrer which not only mixes the basic product continuously to make the finished ice cream as smooth as possible

Methodology Applied
Scientific EffectMixing: Stirring

Implementation Method 3

a mixing and freezing cylinder inside which a basic product is mixed and cooled to obtain a finished product

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2679100B1Stirrer of a machine for making and dispensing ice cream products.
Publication Date: 2014.10.01 ALI SPA CARPIGIANI GRP
  • EP2679100B1 patent drawingFigure 1
  • EP2679100B1 patent drawingFigure 2
  • EP2679100B1 patent drawingFigure 3

AI summary

A stirrer of a machine for making and dispensing ice cream products rotates about an axis (A) inside a cylindrical mixing and freezing unit (2) and comprises a plurality of helical scrapers (7) extending around the axis (A) and operating on an inside wall (10) of the mixing and freezing unit (2) to be scraped, a shaft (3) for rotating the stirrer (1) about the axis (A) and mounting the helical scrapers (7) at a first end (8) of them. Each helical scraper (7) comprises a guide (16) and at least one scraping member (12) which can be slidably coupled to and uncoupled from the guide (16).