Hydraulic Chassis Lifting Valve Block With Pressure Accumulator
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Solution Overview
Problem
Hydraulic lifting devices for medical equipment face issues with unintentional lowering due to leakage through non-return valves, which cannot be reliably prevented with single protection mechanisms, especially at low holding pressures, leading to increased size and cost when redundant protection is implemented.
Innovation Solution
Incorporating a pressure accumulator downstream of secondary non-return valves in the valve block to compensate for pressure losses and leakage, allowing for hierarchical pressurization of cylinder devices without increasing the valve block's size or weight, using small-volume spring accumulators that can be integrated directly into the valve block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant non-return valves are used to prevent leakage, then reliability is improved, but device complexity and size increase
Solution Approach 1:
A pressure accumulator is introduced as an intermediary component between the non-return valve and the cylinder device. The accumulator compensates for leakage by storing pressurized hydraulic fluid, maintaining system pressure without requiring additional non-return valves. This mediator approach resolves the contradiction by preventing unintentional lowering while avoiding the complexity and size increase associated with redundant valve arrangements
Solution Approach 2:
The invention utilizes hydraulic principles by implementing a pressure accumulator that stores pressurized hydraulic fluid. The accumulator uses the compressibility of gas or elastic deformation of a bladder to absorb pressure fluctuations and compensate for leakage. This hydraulic approach provides reliable prevention of unintentional lowering without increasing device complexity, as the accumulator integrates smoothly into the existing hydraulic circuit
2Ease of operation
If holding pressure is reduced, then ease of operation is improved, but reliability deteriorates due to increased leakage effects
Solution Approach 1:
The pressure accumulator provides a feedback mechanism that automatically compensates for pressure losses. When leakage causes pressure to drop, the accumulator releases stored pressurized fluid to maintain the required holding pressure. This feedback loop ensures that even at reduced holding pressures where leakage effects are more pronounced, the system maintains reliability without requiring increased operation force
Solution Approach 2:
The pressure accumulator is pre-charged with pressurized hydraulic fluid before operation. This beforehand cushioning of pressure ensures that when the system operates at lower holding pressures, the accumulator can immediately compensate for any leakage-induced pressure drops, maintaining reliability without compromising ease of operation
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
Effectively prevents unintentional lowering by compensating for pressure losses and leakage, maintaining the lifted position of medical devices without increasing the valve block's size or weight, thus reducing costs and ensuring reliable operation.
Implementation Method 1
the valve block has at least one pressure accumulator in the flow direction from the pump to the second cylinder device downstream of the at least one secondary non-return valve
Implementation Method 2
using small-volume spring accumulators that can be integrated directly into the valve block
Data Source
AI summary
A hydraulic lifting device for a chassis of a mobile device has a valve block, a pump, a tank, a first cylinder device and a second cylinder device. The first cylinder device and the second cylinder device can be selectively pressurized by the pump or connected to tank via the valve block. The first cylinder device is connected to the pump via at least one primary non-return valve disposed in the valve block. The second cylinder device is connected to the pump via at least one secondary non-return valve disposed in the valve block. The valve block has at least one pressure accumulator downstream of the at least one secondary non-return valve in the flow direction from the pump to the second cylinder device. Furthermore, a chassis with such a lifting device and to a mobile device with a chassis is provided.