Cryogenic Pump Rotor Sealing With Glass Fiber Hermetic Cover
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Solution Overview
Problem
The motor rotor in pump apparatuses for cryogenic liquefied gases, such as liquid hydrogen or liquefied natural gas, is prone to deformation and breakage due to high-speed rotation and exposure to liquefied gas, which weakens its mechanical strength and generates large centrifugal forces.
Innovation Solution
The pump apparatus incorporates a hermetic cover made of glass fiber and balance rings to form a sealed space around the motor rotor, along with reinforcing covers made of glass fiber or non-magnetic metal to enhance mechanical strength and protect the rotor from liquefied gas, preventing deformation and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump apparatus rotates at high speed to handle liquefied gas with small specific gravity, then the productivity is improved, but the motor rotor may be deformed or broken due to large centrifugal force
Solution Approach 1:
A hermetic cover made of glass fiber is introduced as an intermediary component between the motor rotor and the liquefied gas environment. This hermetic cover protects the motor rotor from direct exposure to liquefied gas while allowing the pump to operate at high speeds. The glass fiber material provides both hermetic sealing and mechanical reinforcement to withstand centrifugal forces.
Solution Approach 2:
The hermetic cover is constructed from glass fiber, a composite material that combines the benefits of high strength-to-weight ratio with resistance to liquefied gas. This composite material enables the cover to withstand the large centrifugal forces generated during high-speed operation while maintaining structural integrity and protecting the motor rotor.
2Use of energy by moving object
If the motor rotor is exposed to liquefied gas for cooling, then the use of energy is improved, but the mechanical strength of the motor rotor decreases over time
Solution Approach 1:
The hermetic cover acts as a mediator that allows thermal energy transfer from the liquefied gas to the motor rotor while preventing direct contact between the liquefied gas and the motor rotor. This enables continuous cooling of the motor rotor during high-speed operation without the material degradation that would result from direct exposure to liquefied gas.
Solution Approach 2:
The hermetic cover functions as a protective shell that encloses the motor rotor. This thin-walled glass fiber structure provides hermetic sealing and mechanical protection while allowing thermal conduction for efficient cooling. The shell structure maintains the motor rotor's mechanical strength by preventing direct contact with the erosive liquefied gas environment.
3Reliability
If a hermetic cover made of glass fiber is used to protect the motor rotor, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The hermetic cover made of glass fiber serves multiple functions simultaneously: it provides hermetic sealing to isolate the motor rotor from liquefied gas, acts as a structural reinforcement to withstand centrifugal forces, and facilitates thermal conduction for motor cooling. By combining these functions into a single component, the overall device complexity is minimized while maintaining high reliability.
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 hermetic and reinforcing covers effectively isolate the motor rotor from liquefied gas, enhancing mechanical strength and preventing deformation and damage, even at ultra-high speeds, while maintaining motor performance and reliability.
Implementation Method 1
a hermetic cover fixed to outer circumferential surfaces of the side rings, the hermetic cover being made of glass fiber
Implementation Method 2
the hermetic cover being made of glass fiber
Implementation Method 3
balance rings arranged outwardly of the side rings, respectively, in an axial direction of the rotational shaft; and a non-magnetic metal cover fixed to outer peripheral surfaces of the balance rings, wherein the non-magnetic metal cover and the balance rings form a sealed space in which the hermetic cover, the side rings, and the motor rotor are disposed
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The present invention relates to a pump apparatus for delivering cryogenic liquefied gas, such as liquid hydrogen or liquefied natural gas, and in particular to a pump apparatus having an electric motor as a driving source for a pump. The pump apparatus includes a pump (1) having an impeller (2), a rotational shaft (5) to which the impeller (2) is fixed, and an electric motor (7) for rotating the rotational shaft (5) and the impeller (1). A rotor assembly (21) of the electric motor (7) includes a motor rotor (40) fixed to the rotational shaft (5), side rings (41) arranged at both sides of the motor rotor (40), and a hermetic cover (42) fixed to outer circumferential surfaces of the side rings (41). The hermetic cover (42) is made of glass fiber.