Hydraulic Flow Control Circuit for Stable User-Point Pressure
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Solution Overview
Problem
Existing hydraulic circuit systems face challenges in maintaining constant pressure differences at user points, especially when flow rate demands exceed the maximum displacement of the main pump, leading to energy dissipation and unstable operation.
Innovation Solution
A circuit for flow rate control in hydraulic systems that incorporates a main pump and an auxiliary pump, utilizing valve means to optimize the operation of both pumps, ensuring the pressure difference at user points remains at the design value by efficiently managing the flow rates and minimizing energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the main pump displacement is increased to meet higher flow rate demands, then the flow rate delivery capability is improved, but the pressure difference at user points cannot be maintained when exceeding maximum displacement
Solution Approach 1:
The patent combines a variable displacement main pump with a fixed displacement auxiliary pump in parallel configuration. The auxiliary pump is activated when the main pump reaches its maximum displacement, allowing the system to maintain both high flow rate delivery and pressure difference maintenance by merging the capabilities of both pumps.
Solution Approach 2:
The system dynamically switches between main pump-only operation and combined main-auxiliary pump operation based on flow rate demands. The auxiliary pump is engaged when additional flow is needed beyond the main pump's maximum capability, and disengaged when the main pump can satisfy demand alone, optimizing both productivity and pressure maintenance.
2Loss of energy
If the auxiliary pump is connected to the discharge tank when flow rate demand is slightly higher than main pump maximum, then energy dissipation is reduced, but the pressure difference at user points drops below design value
Solution Approach 1:
The system uses pressure differential feedback from the user points to control the auxiliary pump operation. When the pressure difference drops below the design value, the auxiliary pump is automatically re-engaged to restore proper pressure, ensuring both energy efficiency and pressure stability are maintained through continuous monitoring and adjustment.
Solution Approach 2:
The system changes the operational parameters of the auxiliary pump based on system conditions. The auxiliary pump operates in two distinct states: delivering flow to the circuit when needed, or being connected to the discharge tank when not needed. This parameter switching allows energy dissipation to be minimized while pressure difference stability is maintained through proper timing of the transitions.
3Ease of operation
If the valve means continuously modulate when the auxiliary pump is choked towards the discharge tank, then flow control is achieved, but noise increases
Solution Approach 1:
Instead of continuous modulation, the valve means operate in periodic on/off cycles or discrete position changes. The auxiliary pump is periodically engaged and disengaged based on system needs, and the valve switches between discrete positions (connected to circuit or connected to discharge tank) rather than continuously modulating, thereby achieving flow control while minimizing noise generation.
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 proposed solution maintains the pressure difference at user points at the design value under all operating conditions, providing a more stable and efficient operation compared to existing systems, while minimizing energy dissipation and optimizing the use of both main and auxiliary pumps.
Implementation Method 1
a variable displacement main pump (2a) with delivery line (3) connected to the hydraulic circuit
Implementation Method 2
adjustment means for adjusting the displacement (compensating element) of the main pump so as to keep substantially constant the pressure drop at the ends of a user point
Implementation Method 3
valve means that, depending on the pressure difference at the ends of the choke, are adapted to supply the thrust chamber with the working fluid under pressure
Implementation Method 4
an auxiliary pump (5a) with auxiliary supply line (6) connected in a fluid-operated manner to the auxiliary pump (5a) and to the delivery line (3)
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The circuit for the flow rate control in a hydraulic circuit, comprises: main pumping means (2) with variable displacement; a delivery line (3) connected to said the pump and along which at least one user point (4) is arranged; auxiliary pumping means (5) comprising at least one auxiliary pump (Sa); an auxiliary supply line (6) connected to the auxiliary pump (Sa) and to the delivery line (3); one discharge tank (7, 8); valve means (9, 13) operable to set in communication/isolate the auxiliary pumping means (5) with/from the tank (7, 8); wherein the valve means (9, 13) comprise first valve means (9) movable between at least a discharge position and a supply position, at least one first driving line (10) of the first valve means (9), and comprise second valve means (13) operable between at least a first working position and a second working position, at least a second driving line (14) and a third driving line (15) being provided operating from opposite sides on the second valve means (13), wherein the second driving line (14) and the third driving line (15) communicates with the delivery line (3) from opposite sides of the user point (4), the second valve means (13) displacing to the first working position as a result of the attainment of a first predefined pressure difference between the second driving line (14) and the third driving line (15) and displacing to the second working position as a result of the attainment of a second predefined pressure difference between the second driving line (14) and the third driving line (15).