Hydraulic Pressure Compensating Valve with Throttle
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Solution Overview
Problem
Existing hydraulic control devices experience leakage losses and high starting resistance for drive motors due to inappropriate shut-off mechanisms, especially at high pressures, which is not tolerable for systems with high maximum pressure and low flow rates.
Innovation Solution
A 2/2-way seat valve design with a throttle in the main flow connection between the pressure source and valve arrangement, allowing a predetermined pressure difference to establish before shut-off, ensuring a 'soft' response and minimizing leakage losses up to 700 bar, using differently sized impact areas and a ring seal for leak-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pressure switch with a sliding fit is used to enable easy adjustability of the control element, then ease of operation is improved, but leakage losses increase at high supply pressure or delivery volume flow
Solution Approach 1:
The pressure switch is divided into a control element and a seat valve that can be independently adjusted. The control element has a sliding fit for easy adjustment, while the seat valve provides leak-free shut-off through a separate adjustment mechanism, separating the adjustment function from the shut-off function to eliminate the contradiction between ease of adjustment and leakage prevention
Solution Approach 2:
A throttling device is introduced as an intermediary component in the control pressure channel. This throttle creates a pressure difference that enables the seat valve to achieve reliable shut-off while the control element maintains its sliding fit for easy adjustment. The throttle acts as a mediator that allows both the ease of adjustment and the leak-free operation to coexist
2Stress or pressure
If the pressure switch shuts off the outflow path immediately to reduce pressure at the valve arrangement, then pressure reduction effectiveness is improved, but starting resistance of the drive motor increases
Solution Approach 1:
The system performs preliminary action by maintaining the outflow path open during motor start-up through the throttling device, allowing the motor to accelerate without immediate counter-pressure. Only after the motor has started does the pressure switch shut off the outflow path to reduce pressure at the valve arrangement, thus preparing the system in advance to avoid starting resistance while still achieving pressure reduction
Solution Approach 2:
The pressure switch dynamically adjusts its behavior based on operating conditions. During motor start-up, the throttle maintains a pressure difference that keeps the outflow path open. Once the motor is running, the pressure switch transitions to shut-off mode to reduce pressure at the valve arrangement. This dynamic response resolves the contradiction between immediate pressure reduction and motor starting requirements
3Force
If an auxiliary volume is added to the control pressure channel to reduce starting resistance, then ease of motor start-up is improved, but device complexity increases
Solution Approach 1:
The throttling device in the control pressure channel serves multiple functions: it creates the pressure difference needed for seat valve operation, enables delayed shut-off to reduce motor starting resistance, and maintains control pressure during start-up. By making the throttle multi-functional, the patent avoids adding separate auxiliary volumes or complex mechanisms, thus reducing device complexity while still achieving ease of motor start-up
4Force
If a throttle is placed in the main flow connection to establish pressure difference, then starting resistance is reduced, but leakage losses increase during operation
Solution Approach 1:
The throttling device is positioned locally in the control pressure channel rather than in the main flow path to and from the valve arrangement. This local placement allows the throttle to create the necessary pressure difference for control purposes without causing significant energy losses in the main hydraulic flow. The control pressure channel is a separate, low-flow path, so throttling there minimizes overall leakage losses while still achieving the desired starting resistance reduction
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 effectively minimizes leakage losses and reduces starting resistance for drive motors, enabling the use of smaller, cost-effective motors and maintaining leak-free shut-off even at high pressures, with negligible losses through the throttle during operation.
Implementation Method 1
a predetermined pressure difference is established across the throttle or a predetermined volume flow through the throttle before the pressure switch shuts off the outflow path
Implementation Method 2
the outflow path to the reservoir is blocked off from the pressure source when the latter is driven, with minimum leakage losses
Data Source
Figure 1~4
Figure 5~6
AI summary
In a hydraulic control device (H) with a switchable pressure source (P), a reservoir (R), and a pressure diverter (W) arranged in a discharge path (13) from the valve assembly (V) to the reservoir (R), which either connects the valve assembly (V) to the reservoir (R) or shuts off from the reservoir (R), and which includes an adjustable control element (16) that can be actuated in a first adjustment direction by a spring (17) and a control pressure derived from the pressure (P1) applied by the valve assembly (V), and in a second adjustment direction to a control position shutting off the discharge path (13) by a control pressure derived from the supply pressure, the pressure diverter (W) is a 2/2-way poppet valve (16) with a leak-free shut-off position and with a valve cone (24) forming the control element (16) and a valve seat (25) arranged in the discharge path (13). The pressure source (P) and the valve assembly are (V) permanently over from the main channel (10,11, 12) a main channel (10, 11, 12) containing a throttle (D), the outflow path (13) branches off between the valve assembly (V) and the throttle (D), and the control pressure acting on the valve cone (24) in the second actuating direction towards the valve seat (25) is derived from the supply pressure between the pressure source (P) and the throttle (D).