Quenching Process Using Liquid Nitrogen Vaporization
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Solution Overview
Problem
High-pressure gas quenching systems require large, expensive storage tanks and energy-intensive compressor systems, leading to inefficiencies and maintenance issues, as well as the need to convert liquid gas back to a gaseous state, wasting energy.
Innovation Solution
A method and apparatus that injects pressurized liquid quenchant into a furnace chamber, allowing it to vaporize rapidly and increase pressure, eliminating the need for high-pressure tanks and compressors, by using liquefied gases like nitrogen, argon, or carbon dioxide, which convert to gas inside the chamber, utilizing stored energy for quenching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If large high pressure gas storage tanks are used to store quenching gas at 30 bar or more, then the quenching pressure can be maintained, but the physical space required and equipment cost increase significantly
Solution Approach 1:
The invention changes the state parameter of the quenchant from liquid to gas at the point of use. Liquid quenchant is injected into the furnace chamber where it rapidly vaporizes, converting to gaseous state and generating the required high pressure (30 bar or more) without requiring large high-pressure storage tanks. This parameter transformation resolves the contradiction by enabling high quenching pressure while minimizing storage volume.
Solution Approach 2:
The invention utilizes phase transition of the quenchant from liquid to gas within the furnace chamber. The liquid quenchant is injected and rapidly vaporizes, absorbing heat and expanding to generate high pressure. This phase transition mechanism allows the system to achieve high quenching pressure without storing gas at high pressure, thereby reducing storage tank volume and associated costs.
2Stress or pressure
If compressor systems are used to charge storage tanks to high pressures, then the required quenching pressure can be achieved, but energy consumption increases and maintenance issues arise
Solution Approach 1:
The system uses the latent heat of vaporization and expansion energy of the liquid quenchant itself to generate the required high pressure. Instead of using external compressors to pressurize storage tanks, the liquid quenchant self-pressurizes as it vaporizes in the furnace chamber. This self-service mechanism eliminates compressor energy consumption and associated maintenance while achieving the required quenching pressure.
Solution Approach 2:
The invention converts the typically wasted energy of vaporizer cooling (when liquid gas is converted back to gaseous state) into useful quenching energy. By injecting liquid quenchant directly into the hot furnace chamber, the vaporization process absorbs heat from the workpiece, providing both cooling and pressure generation simultaneously. This converts what would be energy waste into a beneficial quenching mechanism.
3Ease of operation
If liquid gas is converted back to gaseous state through vaporizers, then delivery is enabled, but energy is wasted in cooling the vaporizer
Solution Approach 1:
The invention directly utilizes the vaporization process within the furnace chamber rather than using separate vaporizers. The liquid quenchant vaporizes in the hot atmosphere, and the heat absorbed during this phase change is used for quenching the workpiece. This eliminates the energy waste of cooling vaporizers by making the vaporization heat absorption the useful quenching mechanism itself.
Solution Approach 2:
The invention extracts the vaporization process from the traditional external vaporizer system and relocates it directly into the furnace chamber. By injecting liquid quenchant directly into the chamber, the system eliminates the intermediate vaporizer step and its associated energy losses, while still achieving the required gas delivery and quenching function.
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 approach reduces the need for large storage tanks and compressor systems, conserves energy, and efficiently cools heat-treated metal parts by rapidly increasing pressure in the furnace chamber, enhancing the quenching process.
Implementation Method 1
injecting a pressurized liquid quenchant into a pressure vessel containing a load of heat treated metal parts such that a vapor of the liquid quenchant forms rapidly and cools the metal parts
Implementation Method 2
The conversion of liquefied gas to the gaseous state inside the furnace chamber utilizes the energy stored in the liquefied gas
Implementation Method 3
the quenchant vapor is circulated in the pressure vessel at high velocity while the liquid quenchant is injected into the pressure vessel such that the quenchant vapor penetrates through the load of metal parts
Implementation Method 4
a vapor of the liquid quenchant forms rapidly and cools the metal parts
Data Source
AI summary
A process for quenching heat treated metal parts using a liquid quenchant and high pressure is disclosed. In general, the process includes the steps of providing a load of heat treated metal parts in a pressure vessel wherein the load is at an elevated temperature after being heat treated. In a subsequent step, a liquid quenchant is injected into the pressure vessel such that a vapor of the liquid quenchant forms rapidly in the pressure vessel and cools the metal parts. The step of injecting the liquid quenchant into the pressure vessel is continued for a time sufficient to establish a desired peak vapor pressure in the pressure vessel. An apparatus for carrying out the disclosed process is also described.