Frozen Sand Mold Refrigeration With Multi-Path Freezing and Easy Demolding

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Solution Overview

Problem

The conventional casting industry faces challenges such as long manufacturing cycles, high labor intensity, expensive product development, and inefficient freezing processes for frozen sand molds, leading to high energy consumption and difficulty in demolding.

Innovation Solution

A refrigeration device and method utilizing a frozen sand mold chamber with a teflon porous lining, removable porous aluminum plate, and ultrasonic piezoelectric sheet, combined with a low-temperature refrigeration system using liquid nitrogen and a U-shaped condenser tube, to achieve rapid freezing and efficient demolding of frozen sand molds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional freezing methods are used for large-sized frozen sand billets, then the freezing process can be completed, but the freezing time becomes excessively long and energy consumption increases

Engineering Contradiction:
Improvefreezing speedVSAvoidfreezing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The freezing system is segmented into multiple independent refrigeration units with separate evaporators positioned at different locations within the molding chamber. This allows simultaneous freezing from multiple directions and regions, significantly reducing the overall freezing time for large-sized sand billets compared to conventional single-point freezing methods

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional single-point or surface freezing to multi-point three-dimensional freezing by positioning evaporators in vertical, horizontal, and diagonal orientations throughout the molding chamber. This spatial distribution of freezing points enables rapid heat extraction from the entire billet volume simultaneously

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If conventional sand mold production processes are used, then casting can be produced, but the manufacturing cycle is long and labor intensity is high

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmanufacturing cycle
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention replaces conventional mechanical sand handling, molding, and freezing operations with an integrated automated system where sand is deposited directly into the molding chamber and frozen in-situ using refrigeration units. This eliminates multiple manual processing steps, reduces labor intensity, and significantly shortens the manufacturing cycle

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention merges the molding and freezing operations into a single integrated process. The sand is molded and frozen within the same chamber using the same equipment system, eliminating the need for separate molding and freezing facilities and reducing overall process time

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional freezing equipment is used, then frozen sand molds can be produced, but demolding becomes difficult and costly

Engineering Contradiction:
Improvedemolding easeVSAvoiddemolding complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts the frozen sand mold from the molding chamber using a lifting mechanism that separates the mold from the chamber walls. The removable evaporators and modular chamber design allow the mold to be extracted without complex demolding operations, reducing both difficulty and cost compared to conventional frozen mold release methods

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables rapid freezing and efficient demolding of frozen sand molds, reducing energy consumption and improving machining quality while extending tool life, thus enhancing the economic efficiency and productivity of the casting process.

Implementation Method 1

the ultrasonic piezoelectric sheet is located between the teflon porous lining and the removable porous aluminum plate

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

the ultrasonic piezoelectric sheet is located between the teflon porous lining and the removable porous aluminum plate and fixed at a bottom of the teflon porous lining

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

the U-shaped condenser tube is located inside the frozen sand mold refrigeration device box; the liquid nitrogen tank is connected to the low-temperature gas mixing chamber through a first pipeline

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

the liquid nitrogen tank is connected to the low-temperature gas mixing chamber through a first pipeline

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 5

the low-temperature refrigeration system comprises a U-shaped condenser tube, a liquid nitrogen tank, a nitrogen tank, a flow meter, one-way valves, and a low-temperature gas mixing chamber

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4393618B1Refrigeration device and refrigeration method for frozen sand mold
Publication Date: 2025.12.24 NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
  • EP4393618B1 patent drawingFigure 1~2
  • EP4393618B1 patent drawingFigure 3(a)~5

AI summary

The present invention discloses a multi-path internal microporous efficient refrigeration method and device for a frozen sand mold. The device includes a frozen sand molding chamber, an electric lifting platform, a teflon porous lining, a removable porous aluminum plate, a frozen sand mold refrigeration device box, a sealing cover plate, an ultrasonic piezoelectric sheet, a U-shaped condenser tube, an ultrasonic generator, and a low-temperature refrigeration system. The teflon lining and the removable porous aluminum plate are provided with through hole structures of the same size and shape for rapid cooling from the surface to core of molding sand. The lifting platform is opened and the bumpy-ridge teflon lining rises to a highest point to facilitate demolding. The high- and low-frequency dual mode of the ultrasonic piezoelectric sheet can be used for vibrating and compacting the frozen sand mold, and can also assist in cutting forming. The device can achieve rapid freezing of the frozen sand mold, convenient demolding, and low-cost digital forming.