Cryogenic Pump Motor Thermal Segmentation
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Solution Overview
Problem
Conventional cryogenic pumps for liquefied gases face issues such as leakage, high material costs due to the need for specialized bearings and materials, increased precooling time, and inefficiencies due to heat transfer and vaporization, particularly in sealless pumps where the motor and bearing are submerged in the cryogenic liquid.
Innovation Solution
A cryogenic pump design with a heat adjusting unit between the motor and impeller, maintaining the impeller in the liquid phase and the motor in the gas phase, allowing for reduced precooling time, lower liquid level requirements, and cost-effective materials, eliminating the need for expensive bearings and minimizing heat transfer to the cryogenic liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor and impeller are both submerged in cryogenic liquefied gas (submerged pump design), then the pump achieves sealless operation and eliminates leakage risks, but the bearing and motor materials become extremely expensive due to cryogenic embrittlement requirements
Solution Approach 1:
The pump is divided into two distinct zones: a cryogenic liquid-phase zone containing the impeller and a non-cryogenic gas-phase zone containing the motor. The heat adjusting unit acts as a thermal boundary between these zones, allowing each component to operate in its optimal temperature environment and use appropriate materials.
Solution Approach 2:
The heat adjusting unit serves as a thermal intermediary between the cryogenic liquid-phase environment and the motor, preventing direct heat transfer that would cause cryogenic embrittlement. This intermediary structure enables the motor to operate in a warmer gas phase while the impeller operates in the cryogenic liquid phase.
2Device complexity
If the motor is submerged in cryogenic liquefied gas, then the pump achieves compact integration, but the precooling time increases significantly and vaporization losses increase
Solution Approach 1:
The pump system is segmented into a liquid-phase section requiring precooling (impeller area) and a gas-phase section not requiring precooling (motor area). This segmentation reduces the total volume requiring precooling, thereby reducing precooling time and vaporization losses.
Solution Approach 2:
Different thermal conditions are applied to different parts of the pump: the impeller region is maintained in the cryogenic liquid phase for proper operation, while the motor region is maintained in a warmer gas phase to avoid precooling requirements and reduce vaporization losses.
3Device complexity
If the motor is positioned in the liquid phase, then the pump structure is simplified, but heat transfer from the motor to the cryogenic liquid causes increased vaporization and energy loss
Solution Approach 1:
The heat adjusting unit acts as a thermal intermediary that blocks direct heat transfer from the motor to the cryogenic liquid. By positioning the motor in the gas phase and using the heat adjusting unit as a thermal barrier, the system minimizes parasitic heat transfer and associated vaporization losses.
Solution Approach 2:
The pump employs local thermal zone control where the impeller operates in the cryogenic liquid phase and the motor operates in a warmer gas phase. This local differentiation of thermal conditions reduces overall heat transfer to the cryogenic liquid and minimizes vaporization losses.
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
This design reduces vaporization losses, improves pump efficiency, lowers production costs, and minimizes the risk of cryogenic liquefied gas leakage, while maintaining the impeller in the liquid phase and motor in the gas phase, thus avoiding structural and material inefficiencies of conventional pumps.
Implementation Method 1
a heat adjusting unit (11) between the motor (1) and the impeller (2), for maintaining existence of the impeller (2) in a liquid phase of the cryogenic liquefied gas and maintaining existence of the motor (1) in a gas phase of the cryogenic liquefied gas
Data Source
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AI summary
A cryogenic pump for liquefied gases is provided, which shortens precooling time, has a small loss of cryogenic liquefied gas, excels in pump efficiency, and is advantageous in cost. A motor 1 and an impeller 2 are coupled by a shaft 3 for transmitting a rotative drive force therebetween, and the motor 1 is arranged on an upper side and the impeller 2 is arranged on a lower side. The motor 1 and the impeller 2 exist in an enclosed space 14 where they are communicated with each other and into which the cryogenic liquefied gas is introduced. A heat adjusting unit 11 is provided between the motor 1 and the impeller 2, the heat adjusting unit maintaining existence of the impeller 2 in a liquid phase of the cryogenic liquefied gas and maintaining existence of the motor 1 in a gas phase of the cryogenic liquefied gas. Thus the submerging of the motor 1 in the liquid becomes unnecessary, whereby the precooling time can be reduced remarkably and the loss of cryogenic liquefied gas due to vaporization caused by the submerging can be reduced, and in addition, the motor 1 itself can be configured at a comparatively low cost.