Hydraulic Circuit for Load-Sensing Pump Control
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Solution Overview
Problem
Existing circuit arrangements for load-sensing control pumps in series connections require complex and costly electrical control systems to manage standby and active operations, leading to increased manufacturing and operational effort, especially when used in mobile work machines like winter service spreaders.
Innovation Solution
A hydraulically actuated circuit arrangement that switches between active and standby operations without electrical components, using a directional control valve and metering orifice to adjust volume flow requirements, allowing the load-sensing pump to operate efficiently without electrical control, and enabling seamless transition between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrical control system is used to manage standby and active operations of load-sensing pumps in series connections, then the pump operation can be precisely controlled, but the manufacturing cost and operational complexity increase
Solution Approach 1:
The patent replaces the electrical control system with a purely hydraulic control system. The directional control valve is actuated hydraulically through the LS control line, and the metering orifice is controlled by hydraulic pressure differential, eliminating all electrical components while achieving precise pump operation control.
Solution Approach 2:
The invention uses hydraulic pressure from the LS control line to control the directional control valve and metering orifice. The control pressure acts against a compression spring on the valve piston, and the metering orifice is controlled by the balance between control pressure and spring force, creating a fully hydraulic control mechanism.
2Productivity
If a fixed displacement pump is used in series connections, then the complete pump volume flow is available to each consumer, but the pump volume cannot be adjusted to match actual demand
Solution Approach 1:
The patent makes the pump system dynamic by using a load-sensing pump that can adjust its delivery volume flow based on actual demand. The metering orifice is controlled by hydraulic pressure to vary the flow rate, allowing the system to adapt to changing load conditions and eliminate excess volume flow that would otherwise be wasted.
Solution Approach 2:
The invention changes the flow parameter by using a metering orifice whose opening is controlled by hydraulic pressure. The control pressure from the LS control line varies the effective cross-section of the metering orifice, thereby dynamically adjusting the volume flow rate to match actual consumer demand.
3Ease of operation
If an upstream throttle valve is used to control the load-sensing pump, then the pump can be switched to standby mode, but additional electrical control components are required
Solution Approach 1:
The patent extracts the electrical control function from the system and replaces it with a purely hydraulic control mechanism. The directional control valve and metering orifice are controlled entirely by hydraulic pressure from the LS control line, eliminating the need for electrical actuators, sensors, and control electronics while maintaining standby mode switching capability.
Solution Approach 2:
The hydraulic control system is self-regulating through the balance between control pressure acting on the valve piston and the compression spring force. The system automatically adjusts the metering orifice opening based on the hydraulic pressure differential, requiring no external electrical control signals or additional control components.
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 manufacturing and operational costs by eliminating the need for electrical control systems, ensuring reliable and efficient operation of load-sensing pumps in series connections, maintaining functionality and allowing compatibility with both load-sensing and fixed displacement pumps.
Implementation Method 1
the control pressure acts against the action of a compression spring on the opposite control side of the valve piston of the valve
Implementation Method 2
a metering orifice being connected between the valve and at least one hydraulic consumer in the assignable feed line
Data Source
AI summary
A circuit arrangement for controlling hydraulic consumers (10, 12, 14) which are connected in series and which are supplied for their operation by at least one load-sensing control pump (17) via a pressure supply connection (P), which can each be operated between a standby operation and a working operation and vice versa by means of an assignable valve device, which is arranged between the pressure supply connection (P) and a supply line (A1) of at least one hydraulic consumer (10) and has an actuable valve (40), is characterized in that the valve (40) can be controlled exclusively hydraulically, that at least one actuation signal for the control thereof originates from a load tap (34) at least on one of the hydraulic consumers (10), and that a measuring orifice (46) is connected between the valve (40) and at least one hydraulic consumer (10) in the assignable supply line (A1).