Cryogenic Reciprocating Pump Cylinder Structure for Cooling Assistance
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Solution Overview
Problem
Conventional cryogenic liquid reciprocating pumps face challenges such as backflow due to negative pressure, excessive pressure resistance, and increased risk of failure due to temperature-related issues.
Innovation Solution
The design incorporates a pump housing with a suction chamber and a discharge chamber, where the upper space of the suction chamber is used for pressurization and the lower space is open to prevent negative pressure, and the cryogenic target liquid is used for natural cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single control volume is used for pumping in the suction chamber, then the pump structure is simplified, but backflow occurs due to excessive negative pressure during suction
Solution Approach 1:
The suction chamber is divided into two separate control volumes: a first control volume (upper space) for suction and pressurization, and a second control volume (lower space) for cooling and pressure equalization. This segmentation allows independent pressure control in each zone, preventing backflow in the pumping zone while maintaining structural simplicity
Solution Approach 2:
The second control volume acts as an intermediary that communicates with the external cryogenic liquid through an opening. It serves as a buffer zone that equalizes pressure during the suction stroke, preventing excessive negative pressure in the first control volume that would cause backflow
2Stress or pressure
If excessive pressure is applied to the control volume where pumping is not required, then pressure equalization is achieved, but it acts as resistance to the pumping process
Solution Approach 1:
The communication between the first and second control volumes is dynamically controlled through check valves. During the suction stroke, the second control volume communicates with external liquid to equalize pressure. During the discharge stroke, the check valves close off the second control volume, preventing it from acting as resistance to the pumping process in the first control volume
3Temperature
If the pump operates at extremely low temperatures, then cryogenic liquid pumping is achieved, but the risk of failure increases due to heat shrinkage and brittleness
Solution Approach 1:
The second control volume is opened to the external cryogenic liquid, allowing the pump components to be directly cooled by the cryogenic liquid during operation. This self-cooling mechanism maintains operational temperature and reduces thermal stress, preventing heat shrinkage and brittleness-related failures
Solution Approach 2:
The design anticipates thermal effects by providing continuous cooling through the second control volume before thermal damage can occur. The opening to external cryogenic liquid ensures that components are pre-cooled and maintained at operational temperatures, cushioning against thermal shock and progressive degradation
4Shape
If the port is formed on the curved side of the cylindrical chamber, then the chamber structure is compact, but valve application becomes difficult
Solution Approach 1:
While the overall chamber maintains a compact cylindrical shape with curved sides, the check valves are specifically positioned on the upper surface (flat or accessible area) of the first control volume. This local differentiation allows valve installation and maintenance while preserving the compact cylindrical design
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 configuration effectively prevents excessive or negative pressure, reduces the risk of failure, and allows for natural cooling of the pumping chamber, enhancing the pump's operational reliability and efficiency.
Implementation Method 1
the upper space of the suction chamber, the piston, and the piston rod are cooled by the target liquid
Implementation Method 2
natural cooling of the pumping chamber
Data Source
AI summary
A reciprocating pump for pressurizing a cryogenic liquid includes a pump housing, a suction chamber, a discharge chamber and a piston rod and a piston. The pump housing has a suction part into which a target liquid flows. The suction chamber is disposed in the pump housing, has an inner space divided into an upper space and a lower space, and is configured to inhale the target liquid then to pressurize the inhaled target liquid primarily. The discharge chamber is disposed under the suction chamber, has an inner space formed to be connected with the upper space of the suction chamber, and is configured to receive the pressurized target liquid in the suction chamber, to pressurized the received target liquid secondarily and then to discharge the pressurized target liquid. The piston rod and the piston are configured to the target liquid in the suction chamber and the discharge chamber.