Self-Rotating Hydraulic Control Valve for Cavitation Durability

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Solution Overview

Problem

Existing control valves in hydraulic impact devices of rock breaking apparatuses face durability issues due to cavitation damage and require external actuators for position changes, which complicates their design and operation.

Innovation Solution

A control valve with elongated, slanted surfaces on its radial surfaces that rotate due to fluid flow, allowing automatic position adjustment without external forces, thereby enhancing durability and reducing cavitation damage, and can be manufactured with slight modifications to existing structures using methods like additive manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional control valves are used without slanted surfaces, then the structure is simple and manufacturing is easy, but the valve requires external actuators for position changes and suffers from cavitation damage reducing durability

Engineering Contradiction:
Improvedurability of control valveVSAvoidstructure of control valve
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control valve utilizes the hydraulic fluid flow itself to generate torque on the slanted surfaces, enabling self-rotation and automatic position adjustment without requiring external actuators. The fluid that passes through the valve serves dual purposes: controlling the impact device and actuating the valve rotation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention employs hydraulic pressure and fluid flow dynamics to create rotational motion. The slanted surfaces are designed to exploit the pressure differential and flow direction of hydraulic fluid, converting linear fluid flow into rotational valve movement through hydrodynamic forces.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Ease of operation

If external actuators are used to change valve position, then precise control is achieved, but the device complexity increases and durability decreases due to additional failure points

Engineering Contradiction:
Improveautomatic position adjustmentVSAvoidactuator system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control valve autonomously adjusts its position by utilizing the hydraulic fluid flow that is already present in the system. The slanted surfaces convert the linear motion of fluid flow into rotational motion, eliminating the need for separate actuation mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention removes the external actuator component from the system entirely, extracting the actuation function and integrating it directly into the valve structure through the slanted surface geometry. This simplifies the overall system by eliminating unnecessary parts.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If the control valve is subjected to cavitation, then it can control high pressure fluid flows, but cavitation causes damage to the valve surfaces reducing durability

Engineering Contradiction:
Improvehydraulic pressure controlVSAvoidcavitation damage
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The rotating control valve continuously changes its orientation relative to the fluid flow, which helps to distribute cavitation effects across different surface areas and prevents localized pitting damage. The rotation mechanism allows the valve to adapt to varying flow conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The valve transitions from a static component to a dynamic rotating element that continuously adjusts its position during operation. This dynamic behavior allows the valve to optimize its orientation relative to the fluid flow, reducing the impact of cavitation on any single surface area.

Inventive Principle:
Principle #15Dynamics

4Reliability

If slanted surfaces are added to the control valve, then automatic rotation and durability are improved, but manufacturing complexity increases slightly

Engineering Contradiction:
Improvedurability of control valveVSAvoidmanufacturing of slanted surfaces
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The slanted surfaces are designed with specific geometric parameters (angle, curvature, distribution) that optimize the conversion of fluid flow into rotational torque. These parameters are carefully selected to achieve effective valve rotation while remaining compatible with standard manufacturing processes.

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 solution increases the durability of control valves by allowing automatic position changes without external actuators, reduces cavitation damage, and simplifies manufacturing, while maintaining efficient operation of hydraulic impact devices in rock breaking apparatuses.

Implementation Method 1

the fluid flow causes on the slanted surfaces torque around the central axis of the control valve and makes the control valve to rotate

Methodology Applied
Scientific EffectFluid flow force: Drag

Implementation Method 2

the fluid flow causes on the slanted surfaces torque around the central axis of the control valve

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 3

The control valve may be subjected to cavitation whereby cavitation damages of the control valve can be decreased

Methodology Applied
Scientific EffectCavitation: Cavitation

Data Source

PatentEP4261441A1Control valve, impact device and method
Publication Date: 2023.10.18 SANDVIK MINING & CONSTR OY
  • EP4261441A1 patent drawingFigure 1~2
  • EP4261441A1 patent drawingFigure 3~4
  • EP4261441A1 patent drawingFigure 5~6

AI summary

A control valve, an impact device for a rock breaking apparatus, and a method. The control valve (26) is an elongated piece with a central axis and radial outer and inner surfaces (Ros, Ris). The control valve comprises several control surfaces at axial distances from each other for controlling hydraulic fluid flows (Hff) in response to axial control movement (M). One or more radial surfaces of the control valve comprise one or more slanted surface (SS) longitudinal direction of which have oblique orientation in relation to the central axis (Ca) of the control valve. Then the control valve rotates or turns during a working cycle due to hydraulic flow effecting on the slanted surfaces.