Cryogenic Piston Pump Wear Reduction via Hydraulic Reset
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Solution Overview
Problem
Most piston pumps for cryogenic fuels, such as natural gas, experience increased wear in guides and seals due to torsional and transverse forces, leading to reduced service life.
Innovation Solution
A piston pump design with a reciprocating pump piston that uses hydraulic pressure to control movements, featuring an additional pressure chamber coupled to a storage volume prestressed by a return spring, eliminating direct support of the spring on the piston and using a hydraulic stop to limit the working stroke, thereby reducing wear and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a helical compression spring is supported directly on the pump piston to reset the piston, then the pump piston can be reset, but torsional and transverse forces act on the pump piston leading to increased wear in guides and seals
Solution Approach 1:
A guide sleeve is introduced as an intermediary component between the compression spring and the pump piston. The guide sleeve receives the axial force from the compression spring and transmits it to the pump piston, while its cylindrical surface guides the piston during reciprocating motion. This mediator eliminates torsional and transverse forces on the piston, allowing the spring to reset the piston without causing wear in guides and seals.
2Power
If the pump piston is driven mechanically or electrically, then the pump can deliver high pressure fuel, but additional components and complexity are required
Solution Approach 1:
The pump piston is driven purely by hydraulic pressure from fuel in the compression chamber, eliminating the need for mechanical or electrical drive mechanisms. The high pressure fuel itself provides the driving force, creating a self-contained hydraulic drive system that delivers high pressure fuel without additional complex drive components.
3Ease of operation
If a compression spring is used to reset the pump piston, then the piston can return to initial position, but the spring causes increased wear due to lateral forces
Solution Approach 1:
The guide sleeve serves as a mediator that enables the compression spring to perform its reset function while preventing harmful lateral forces. The sleeve's cylindrical geometry constrains the piston to axial motion only, ensuring the spring can reset the piston reliably without compromising the service life of seals and guides.
4Duration of action of stationary object
If the storage volume is not prestressed, then the device is simpler, but the pump piston cannot be effectively reset
Solution Approach 1:
The storage volume is prestressed with a compression spring before operation begins. This preliminary action stores potential energy in the spring, which is then released to drive the pump piston during the reset stroke. The prestressing mechanism ensures reliable piston reset without requiring complex additional components during 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
The design enhances the robustness and service life of the piston pump by minimizing torsional and transverse forces on the piston, reducing wear on guides and seals, and lowering operational noise.
Implementation Method 1
the pump piston moves in the direction of the compression chamber, ie in the direction of an upper end position in which the volume of the compression chamber is minimal. In this case, the pump piston performs a working stroke in which fuel present in the compression chamber is compressed
Implementation Method 2
The storage sleeve that delimits the storage volume moves in the direction of the restoring spring, so that the latter is tensioned. The prestressing force acting on the storage sleeve increases accordingly.
Implementation Method 3
As the working stroke of the pump piston increases, the volume of the additional pressure chamber decreases, with the reduction in volume of the additional pressure chamber being compensated for by an increase in volume of the accumulator volume
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a fuel delivery device for cryogenic fuels, comprising a piston pump (1) for delivering the cryogenic fuel at a high pressure, said piston pump (1) having a pump piston (2) that can be moved back and forth and delimits a compression chamber (3) at one end and a pressure chamber (5), which is formed in a hollow cylinder (4) and to which a hydraulic pressure medium can be supplied, at the other end. According to the invention, the pump piston (2) has an annular shoulder (6) for delimiting an additional pressure chamber (7) which is formed in the hollow cylinder (4) and to which the hydraulic pressure medium can likewise be supplied in order to reset the pump piston (2). The additional pressure chamber (7) is coupled to an accumulator volume (8) which is delimited by an accumulator sleeve (9) that is arranged on the hollow cylinder (4) in a movable manner back and forth and is biased by means of a return spring (10).