Load-Sensing Hydraulic Valve With Integrated Check Orifice

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Solution Overview

Problem

Fluid systems with variable flow rates and pressures require efficient pump control and power management, but existing hydraulic valves are inefficient in terms of power consumption and size.

Innovation Solution

A proportional load sensing hydraulic valve with a spool and check valve configuration that balances load sense pressure with work port pressures, using a metering orifice and pressure compensator to optimize fluid communication and reduce energy loss, integrated within a hydraulic system with a variable displacement pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional hydraulic valve is used to control variable flow rates and pressures, then the system can meet variable fluid requirements, but the valve size and power consumption increase

Engineering Contradiction:

Improvevariable flow rates and pressuresVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The check valve and metering orifice are integrated into the load sensing port of the proportional valve, combining multiple functions (flow control, pressure sensing, and load compensation) into a single compact component. This merging eliminates the need for separate external check valves and reduces the overall valve size while maintaining adaptability to variable flow and pressure requirements

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The load sensing port is designed to serve multiple functions: it acts as a pressure sensing port, incorporates a check valve for flow direction control, and includes a metering orifice for flow regulation. This multi-functionality allows the valve to handle variable flow rates and pressures while reducing the number of separate components needed

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a traditional hydraulic valve is used to control variable flow rates and pressures, then the system can meet variable fluid requirements, but the valve size increases

Engineering Contradiction:

Improvevariable flow rates and pressuresVSAvoidvalve size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The check valve is nested within the load sensing port structure, with the metering orifice integrated into the check valve assembly. This nested arrangement allows multiple functional elements to occupy the same spatial envelope, significantly reducing the overall valve size while maintaining full functionality

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If load sense pressure is communicated to the pressure compensator, then the pump can be controlled to maintain constant pressure drop, but power consumption increases

Engineering Contradiction:

Improveconstant pressure dropVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The metering orifice automatically regulates the flow of load sense pressure to the pressure compensator based on the actual pressure differential requirements. The orifice size and positioning are designed to provide the exact amount of pressure compensation needed without requiring additional power input, allowing the system to self-regulate and maintain constant pressure drop across the work ports

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

The solution decreases power consumption and valve size while maintaining a constant pressure drop across work ports, improving energy efficiency and reducing the size of hydraulic systems by approximately 21%.

Implementation Method 1

The metering orifice is adapted to balance a load sense pressure at the pump port with a pressure at the first and second work ports. The metering orifice moves from the closed position to a metered position when a minimum cracking pressure is reached inside the valve.

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The check valve has a metering orifice biased in a closed position by a check valve spring.

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 3

The spool is adapted to move along the major axis between a rested position, a first activated position, and a second activated position; wherein fluid communication is blocked between the pump port and the first and second work ports when the spool is in the rested position

Methodology Applied

Scientific EffectFluid pressure: Pressure Gradient

Data Source

PatentUS11459220B2Hydraulic system with load sense and methods thereof

Publication Date: 2022.10.04 DANFOSS AS

AI summary

A hydraulic system includes a pump in communication with a fluid reservoir and powered by a motor. A pressure compensator is adapted to adjust a position of a variable displacement mechanism of the pump. A load sensing line is adapted to communicate a highest load sensing pressure from a plurality of valves to the pressure compensator. The pressure compensator adjusts the variable displacement mechanism of the pump based on the highest load sensing pressure for maintaining a constant pressure drop across one or more work ports in each of the plurality of valves. The plurality of valves each include a load sense port having an integrated check valve that includes a metering orifice.