Cryogen Spray Temperature Control With Proportional Gas Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cryogenic cooling systems face challenges in providing precise temperature control due to overcooling or undercooling issues, heat loss, and pressure fluctuations, which can lead to surface damage and material fractures, especially when using cryogenic fluids like liquid nitrogen that expand significantly into gas, making real-time pressure adjustments difficult.
Innovation Solution
A dual-phase cooling system that uses a proportional mixture of cryogenic liquid and gas, with a throttling gas supply regulated by a proportional valve controlled by a programmable logic controller (PLC) to maintain a set-point temperature within a predetermined range, ensuring precise temperature control by adjusting the flow rate of the throttling gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cryogen flow rate is increased to match higher heat generation, then cooling capacity is improved, but temperature control precision deteriorates due to overcooling or undercooling
Solution Approach 1:
The system dynamically adjusts the cryogen flow rate in real-time based on feedback from temperature sensors and knowledge of the thermal load. The controller continuously modifies the flow rate to match the actual cooling requirements, preventing both overcooling and undercooling. This dynamic adaptation allows the system to maintain precise temperature control while providing sufficient cooling capacity for varying thermal loads.
Solution Approach 2:
The system incorporates temperature sensors that continuously monitor the temperature of the workpiece or coolant. This temperature feedback is fed to the controller, which compares the measured temperature against the desired setpoint and adjusts the cryogen flow rate accordingly. This closed-loop feedback mechanism enables precise temperature control by automatically correcting deviations caused by varying thermal loads.
2Area of stationary object
If cryogenic liquid is transported over long distances, then cooling coverage is improved, but temperature control precision deteriorates due to pressure drops and gas formation
Solution Approach 1:
The system uses an intermediary mixing chamber where cryogenic liquid is mixed with ambient or pre-cooled gas before being delivered to the workpiece. This mixing process allows for temperature modulation and reduces the impact of pressure drops and gas formation that occur during long-distance transport. The intermediary mixing zone acts as a buffer that stabilizes the coolant temperature and composition before application.
Solution Approach 2:
The system changes the physical parameters of the coolant by controlling the degree of vaporization and mixing ratio of liquid to gas phases. By adjusting these parameters, the system can compensate for temperature changes caused by long-distance transport, pressure drops, and heat exchange with the environment. This parameter control enables precise temperature delivery despite extended transport distances.
3Speed
If adjustable valves are used on cryogenic fixtures for real-time pressure adjustment, then temperature control responsiveness is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical adjustable valves with a simpler fixed-orifice design controlled by electronic modulation of the cryogen supply. Instead of mechanically adjusting valve openings, the system uses electronic control to modulate the cryogen flow through fixed restrictions, achieving the same responsiveness with reduced mechanical complexity. This substitution simplifies the valve control mechanism while maintaining fast response to temperature changes.
4Adaptability or versatility
If external heaters are used for temperature control, then temperature adjustment capability is improved, but ease of operation deteriorates due to difficult implementation and inaccurate control
Solution Approach 1:
The system extracts the heating function from a separate external heater and integrates it into the cryogen delivery system itself. By using the cryogenic coolant as the primary temperature control mechanism and eliminating the need for separate heating elements, the system simplifies implementation while maintaining temperature adjustment capability. The temperature control is achieved purely through modulation of the cryogen flow rate, making the system easier to operate and implement.
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 system effectively maintains the temperature of the resultant fluid within 2.7 degrees C (five degrees F) of the set-point temperature, reducing temperature fluctuations and preventing material damage by precisely regulating the cryogenic coolant delivery.
Implementation Method 1
A dual-phase cooling system that uses a proportional mixture of cryogenic liquid and gas, with a throttling gas supply regulated by a proportional valve controlled by a programmable logic controller (PLC) to maintain a set-point temperature
Implementation Method 2
Cryogenic liquids constantly boil off into large volumes of cryogenic gases. One volume of liquid nitrogen (LIN) transforms into 693 volumes of nitrogen gas (GAN) at room temperature.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fluid spray device system (1 ) that maintains a resultant fluid discharge, or a material onto which the resultant fluid is discharged, within a predetermined range of a set-point temperature by regulating the flow rate of a throttling gas using a proportional valve (22). The resultant fluid has throttling gas and cryogenic fluid components. Both the throttling gas and cryogenic fluid are preferably supplied from a single tank (11 ) and the cryogenic fluid supply is pressure-regulated and includes a triaxial delivery hose (33) having a return line with a back- pressure regulator (54).