Semi-Closed Cooling Circuit With Pressure-Controlled Tank Venting

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Solution Overview

Problem

Existing cooling devices face challenges with coolant loss through evaporation in open systems and complex, pressure-based operations in closed systems, along with the need for additional compensating devices and pumps.

Innovation Solution

A semi-closed cooling circuit design with a venting device that maintains a sealed storage tank connection to the atmosphere, using a submersible pump and pressure-controlled venting to compensate for volume changes, eliminating the need for separate compensating devices and simplifying filling and venting processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an open cooling system is used, then filling and venting are simple and automatic, but coolant loss through evaporation occurs

Engineering Contradiction:
Improvefilling and venting simplicityVSAvoidcoolant loss through evaporation
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The storage tank is equipped with a pressure-regulated venting device that maintains different pressure conditions at different times: atmospheric pressure during filling/venting operations for simplicity, and slight positive pressure during operation to prevent evaporation. This local quality change in pressure state resolves the contradiction between operational simplicity and coolant conservation.

Inventive Principle:
Principle #3Local quality

2Loss of substance

If a closed pressurized cooling system is used, then coolant loss through evaporation is prevented, but filling and venting become complex and require pressure procedures

Engineering Contradiction:
Improvecoolant loss preventionVSAvoidfilling and venting complexity
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

The venting device dynamically adjusts the system pressure state based on operational requirements. During normal operation, it maintains a slight positive pressure (0.01-0.05 bar) to prevent evaporation. During filling or venting operations, it allows pressure equalization to atmospheric pressure, simplifying these operations. This dynamic pressure adjustment resolves the contradiction between evaporation prevention and operational simplicity.

Inventive Principle:
Principle #15Dynamics

3Loss of substance

If a closed cooling system is used, then coolant loss is reduced, but a hydraulic accumulator is required to compensate for volume changes

Engineering Contradiction:
Improvecoolant loss reductionVSAvoidneed for hydraulic accumulator
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The venting device performs multiple functions: it compensates for volume changes caused by thermal expansion and contraction of the coolant, maintains pressure within acceptable ranges, and enables automatic venting when necessary. By integrating these functions into a single device, the patent eliminates the need for a separate hydraulic accumulator, reducing system complexity while maintaining coolant loss prevention.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If a submersible pump is used, then fluid leakage is reduced, but the pump must be installed inside the storage tank

Engineering Contradiction:
Improvefluid leakage reductionVSAvoidpump installation configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pump is nested within the storage tank as a submersible unit, with the motor positioned in the headspace above the coolant level and the pump inlet positioned below the coolant level. This nested configuration allows the pump to be immersed in the coolant for reliable operation while maintaining a compact integrated design that reduces leakage risks compared to external pump connections.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 prevents coolant loss while leveraging the simplicity of open systems and avoiding complex procedures, reducing maintenance and costs by integrating a submersible pump and automatic venting, thus enhancing operational efficiency and reducing fluid leakage.

Implementation Method 1

the venting device, which allows venting of the closed storage tank only when the pressure exceeds or falls below a range corresponding to normal operation, also serves as a compensating device for pressure changes caused by heating or cooling of the medium

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the cooling circuit includes a heat exchanger (20, 22) for cooling the cooling medium (19, 29)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3683077B1Cooling device
Publication Date: 2025.12.17 HYDAC COOLING
  • EP3683077B1 patent drawingFigure 1~2
  • EP3683077B1 patent drawingFigure 3~7
  • EP3683077B1 patent drawingFigure 4

AI summary

2. A cooling device, comprising at least one cooling circuit to which at least one consumer (4) is connected, which in normal operation receives a coolant from a supply pump (14) driven by a motor (12) from a storage tank (6) and which returns the coolant to a heat exchanger (20; 22) which is connected to the outlet side of the storage tank (6), is characterized in that the cooling circuit is designed in the form of a semi-closed cooling circuit, in which the interior of the storage tank (6), which is otherwise closed to the atmosphere, can be connected to the atmosphere via a venting device (42), one of which is a venting or a venting device.The pressure limits allowing venting of the storage tank are specified in such a way that no exchange takes place between the interior of the storage tank (6) and the atmosphere during normal operation and that the supply pump is designed as a submersible pump (14) and is arranged immersed in the coolant level (10) in the storage tank (6).