Welding Cap Cooling Water Flow Control Under Pressure Loss

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Solution Overview

Problem

Existing welding cap cooling water control systems face challenges in efficiently managing cooling water flow, leading to high thermal stress, wear, and reliability issues, particularly in robot spot welding systems, where abrupt pressure changes and water consumption are not optimally regulated, potentially causing loss of welding caps and affecting welding quality.

Innovation Solution

An electronically controlled flow control valve with a specially designed control cone is introduced in the cooling water inlet or outlet, regulating the cooling water flow to welding caps, reducing water consumption, and compensating for line resistance changes, while a control unit and flow sensor monitor and adjust the system to prevent leaks and optimize cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a control valve is switched to CLOSED when changing the welding cap, then the cooling water supply is shut off, but abrupt pressure reduction causes high pressure coolant to escape and causes closing impacts in the cooling water line

Engineering Contradiction:
Improvecooling water control reliabilityVSAvoidclosing impacts and pressure shocks
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The flow control valve is opened in advance before the control valve is closed, allowing cooling water to flow through the welding cap and prevent vacuum formation. This preliminary action eliminates the pressure shock and closing impacts that occur when the control valve is abruptly closed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The flow control valve acts as an intermediary between the control valve and the welding cap cooling system. By controlling the flow rate and maintaining continuous flow through the welding cap, it mediates the pressure changes and prevents abrupt pressure reduction and coolant escape.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If cooling water flow is not regulated, then welding caps are cooled, but excessive water consumption occurs and pump performance is unnecessarily high

Engineering Contradiction:
Improvewelding cap cooling effectivenessVSAvoidcooling water consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The flow control valve is designed to dynamically adjust the cooling water flow rate based on actual cooling requirements. The valve opening is automatically controlled to match the heat input, ensuring optimal cooling while minimizing water consumption. This dynamic adjustment eliminates the need for excessively high pump performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the flow rate parameter of cooling water based on welding conditions. By regulating the flow control valve, the cooling water flow is optimized to match the thermal load, reducing water consumption while maintaining effective cooling of the welding caps.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If cooling hoses are bent or compressed during robot movements, then line resistance changes, but cooling water flow becomes inconsistent

Engineering Contradiction:
Improverobot movement flexibilityVSAvoidcooling water flow consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The flow control valve is controlled based on feedback from welding conditions and cooling requirements. The valve automatically adjusts to maintain consistent cooling water flow through the welding caps, compensating for line resistance changes caused by hose bending or compression during robot movements.

Inventive Principle:
Principle #23Feedback

4Reliability

If a 2-2-way valve is switched to CLOSED in the supply, then cooling water supply is stopped, but water intake devices cannot effectively reduce pressure due to immediate pressure reduction

Engineering Contradiction:
Improvepressure reduction effectivenessVSAvoidwater intake device operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The flow control valve is opened in advance to establish continuous cooling water flow before the control valve is closed. This preliminary action prevents vacuum formation and allows water intake devices to operate effectively by maintaining adequate pressure, eliminating the problem of immediate pressure reduction.

Inventive Principle:
Principle #10Preliminary action

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

This solution reduces water consumption, minimizes service costs, prevents abrupt pressure changes, ensures consistent cooling, and improves welding quality by providing the exact necessary cooling water amounts, even with changing line resistances, and detects leaks, thereby enhancing system reliability and efficiency.

Implementation Method 1

The control cone has a special shape that results in a characteristic flow path. The control cone is thus designed and optimized for specific flow characteristics that result from the axial movement of the closing element in a control opening of the flow control valve.

Methodology Applied
Scientific EffectFlow control through geometric shape:

Implementation Method 2

As mentioned, the flow sensor is located in the return line in particular and can detect the flow rate, the water temperature and/or the pressure. Changes in pressure or flow can then also be detected immediately via the flow sensor, which may also indicate a leak in the cooling water line.

Methodology Applied
Scientific EffectFlow detection:

Implementation Method 3

The welding caps are subject to high thermal stress and wear and are permanently cooled by cooling water.

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 4

The welding caps are subject to high thermal stress and wear and are permanently cooled by cooling water.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3170608B1Welding cap cooling water control
Publication Date: 2021.05.05 BUERKERT WERKE GMBH & CO KG
  • EP3170608B1 patent drawingFigure 1
  • EP3170608B1 patent drawingFigure 2
  • EP3170608B1 patent drawingFigure 3~5

AI summary

A welding cap cooling water control system has a cooling water line with a cooling water inlet (12) leading towards the welding cap (10) and a cooling water return (14) leading away from the welding cap (10), in which a flow sensor (20) and a control valve (22) are located. The cooling water flow is controlled on the inlet or return side by a flow control valve (16), which also serves for emergency shutdown in case of pressure loss.