Pressure Limiting Valve Calibration via Sleeve Positioning

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Solution Overview

Problem

Existing pressure limiting oil-hydraulic valves require time-consuming and complex calibration methods, leading to precision issues and instability in opening at the desired operating pressure, with existing methods being cumbersome and unreliable.

Innovation Solution

A method and apparatus for calibrating pressure limiting valves that involves retaining the closing member in a closed position, detecting the spring reaction force, varying the sleeve position to achieve a predefined force value, and irreversibly locking the sleeve in place without threads, using techniques like plastic deformation or laser welding for precise and quick calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional in-situ calibration method is used, then valve can be calibrated in the hydraulic circuit, but calibration process is time-consuming and complex

Engineering Contradiction:
Improvecalibration operationVSAvoidcalibration time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces the traditional mechanical trial-and-error calibration method with a force detection system. A force sensor detects the reaction force of the spring, and a control unit automatically adjusts the sleeve position based on detected force values, eliminating manual iteration and significantly reducing calibration time.

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

Solution Approach 2:

The calibration system implements closed-loop feedback by continuously detecting the spring reaction force through a force sensor and comparing it with target values. The control unit adjusts the sleeve position based on this feedback until the predefined force value is achieved, ensuring precise and rapid calibration.

Inventive Principle:
Principle #23Feedback

2Reliability

If traditional calibration method with threaded sleeve is used, then valve calibration can be performed, but assembly complexity increases and reliability decreases

Engineering Contradiction:
Improvevalve operation stabilityVSAvoidvalve assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the threaded connection component from the valve assembly. Instead of using a threaded sleeve that requires complex assembly and disassembly, the invention uses a sleeve that is irreversibly locked to the stem through plastic deformation or laser welding, simplifying the overall structure while improving reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The calibration and locking process is performed as a preliminary action during manufacturing. The sleeve is positioned and irreversibly locked to the stem before the valve is installed in the hydraulic circuit, ensuring correct calibration and eliminating the need for future adjustments or maintenance of the connection.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If traditional calibration method is used, then valve can be adjusted, but precision and consistency of operating pressure are compromised

Engineering Contradiction:
Improveoperating pressure precisionVSAvoidopening pressure consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces subjective manual adjustment with objective force detection. A force sensor precisely measures the spring reaction force, and the control unit automatically positions the sleeve to achieve the exact predefined force value, ensuring high measurement precision and consistent operating pressure across all valves.

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

Solution Approach 2:

The calibration system performs self-adjustment through automatic control. The control unit receives force detection signals, compares them with target values, and autonomously adjusts the sleeve position until the predefined force is achieved, eliminating human error and ensuring consistent precision.

Inventive Principle:
Principle #25Self-service

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 approach allows for rapid, precise, and reliable calibration of pressure limiting valves, ensuring consistent operating pressure and improved stability over time, eliminating the need for complex assembly and reducing calibration time significantly.

Implementation Method 1

a spring arranged between the sleeve and the valve body and designed to exert a force on said closing member along the closing direction

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

using techniques like plastic deformation or laser welding for precise and quick calibration

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP2769127B1Apparatus and method for calibrating a valve
Publication Date: 2016.01.06 ST SRL
  • EP2769127B1 patent drawingFigure 1
  • EP2769127B1 patent drawingFigure 2
  • EP2769127B1 patent drawingFigure 3a~5c

AI summary

An apparatus for calibrating a pressure limiting valve, with said valve (1) comprising: a valve body (4) defining a passage (11) for a fluid; a closing member (8) comprising a head (9) and a stem (10) movable with respect to the valve body (4) along a longitudinal direction (X) of extension of the stem from a position (P1) for closing to a position (P2) for opening the passage (11) and vice versa, in an opening direction (OD) and closing direction (CD), respectively; a sleeve (12) which can be joined to said stem (10) of the closing member (8) at an end (51 ) of the stem (10) opposite to said head (9); a spring (S1 ) arranged between the sleeve (12) and the valve body (4) and designed to exert a force on said closing member (8) along the closing direction (CD), the apparatus comprising: means for retaining said closing member (8) in the closed position (P1); means for detecting a value of a reaction force of said spring (S1); means for detecting the position, along the axis of the stem, of the sleeve (12); means for handling the sleeve (12) with respect to the stem (10), designed to allow a variation in position of said sleeve (12) along said stem (10); means for performing threadless connection of the sleeve (12) with respect to the stem (10).