Low-Pressure Suction Accumulator for Hydraulic Pump Cavitation
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Solution Overview
Problem
Hydraulic pumps in aircraft systems are prone to cavitation due to remote hydraulic fluid reservoirs causing substantial line pressure losses and rapid pressure drops, leading to pump failures, with existing solutions increasing weight, complexity, and cost.
Innovation Solution
A low-pressure accumulator is placed directly in the suction line of the hydraulic pump within the engine nacelle, using a spring-loaded metal bellows to rapidly supply pressurized fluid and prevent cavitation by maintaining minimum pressure thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reservoir is placed remotely from the pump, then safety regulations are met and space limitations are addressed, but line pressure losses increase and cavitation occurs
Solution Approach 1:
The system is divided into two parts: a remote reservoir for safety and a local accumulator near the pump for pressure maintenance. The accumulator acts as an intermediate component that segments the function of pressure regulation from the reservoir's primary function of fluid storage and safety compliance.
Solution Approach 2:
The accumulator serves as an intermediary component between the remote reservoir and the pump. It receives fluid from the reservoir and provides pressurized fluid to the pump, mediating the pressure losses that would otherwise occur in the long suction line.
2Reliability
If traditional solutions like increasing reservoir pressure or installing gear pumps are used, then suction line pressure drops are addressed, but weight, system complexity, and expense increase
Solution Approach 1:
The accumulator is a passive device that automatically responds to pressure drops without requiring external control systems. It self-regulates by using the spring-loaded bellows mechanism to discharge fluid when pressure drops occur, eliminating the need for complex active control systems.
Solution Approach 2:
The accumulator uses a simple spring-loaded metal bellows mechanism that is mechanically straightforward and inexpensive compared to active control systems. The design prioritizes simplicity and reliability over longevity, using a compact, maintenance-friendly approach.
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
Prevents cavitation and pump failure by maintaining stable suction line pressures, reducing weight and maintenance needs, and allowing greater reservoir-pump separation.
Implementation Method 1
using a spring-loaded metal bellows to rapidly supply pressurized fluid
Implementation Method 2
A low-pressure accumulator is placed directly in the suction line of the hydraulic pump
Implementation Method 3
Prevents cavitation and pump failure by maintaining stable suction line pressures
Data Source
AI summary
To prevent cavitation damage to a hydraulic fluid pump, a low pressure accumulator is fluidly connected to the suction line of an engine-driven hydraulic pump to boost suction line pressures during instantaneous demands for higher pump flows. The accumulator acts as a localized reservoir for the engine-driven pump to avoid deleterious pressure drops which give rise to pump cavitation. In one disclosed architectural arrangement, the accumulator is directly coupled to the suction line of an aircraft engine-driven hydraulic pump to supply hydraulic fluid upon demand, with both the pump and accumulator contained within an engine nacelle of an aircraft. The low pressure accumulator operates fully independently of a remote main aircraft accumulator, and while the main accumulator operates at thousands of psi, and requires periodic service, the low pressure accumulator operates at less than 30 psi, and is formed of a maintenance-free construction.