Steam Sterilizer Heat Recovery via Indirect Feedwater Preheating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steam sterilizers require significant energy and water consumption, often leading to unnecessary heating of the surrounding environment and inefficiencies in heat recovery, particularly when installed in small spaces.
Innovation Solution
A steam sterilizer design featuring a pressure vessel, membrane pump, and feed water tank with a first heat exchanger for indirect heat transfer, allowing efficient heat recovery and purification of feed water, and a second heat exchanger for further cooling, which reduces energy and water usage while maintaining high steam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If steam is cooled using air coolers or water-free condensers, then water consumption is reduced, but energy recovery efficiency deteriorates and surrounding environment heating increases
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary device between the steam condensation system and the surrounding environment. This heat exchanger transfers heat from the condensing steam to a heat transfer fluid (water or glycol) in a closed circuit, preventing direct heating of the surrounding air while enabling efficient heat recovery for water heating applications
Solution Approach 2:
The system uses the waste heat from steam condensation to preheat feed water for the steam generator, creating a self-service heat recovery loop. The heat that would otherwise be lost to the environment is automatically utilized to reduce the energy required for steam generation
2Loss of energy
If steam is condensed indirectly through heat exchangers, then heat recovery efficiency improves, but device complexity increases
Solution Approach 1:
The heat exchanger serves multiple functions simultaneously: it condenses steam, recovers heat for water heating, and prevents surrounding environment heating. The vacuum pump also performs dual functions of maintaining vacuum conditions and facilitating steam removal. This multi-functionality reduces the need for separate dedicated components
3Loss of energy
If feed water is continuously circulated through heat exchangers, then heat recovery improves, but energy consumption increases
Solution Approach 1:
The feed water circulation through the heat exchanger is implemented as a periodic rather than continuous process. The system alternates between circulation phases for heat recovery and non-circulation phases, reducing pump operating time and energy consumption while still achieving effective heat recovery during active sterilization cycles
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 solution significantly reduces energy and water consumption, allows for larger sterilization chamber volumes, and ensures high steam purity by preventing contamination, while also reducing non-condensable gases and biofilm formation in the feed water tank.
Implementation Method 1
the first fluid discharge line is routed through a first heat exchanger with exclusively indirect heat transfer. In this case, a fluid flowing through the first fluid discharge line serves as a heat-emitting medium, while feed water serves as a heat-absorbing medium
Implementation Method 2
a second heat exchanger for further cooling
Implementation Method 3
The vacuum pump, which is designed in particular as a water-free vacuum pump such as a membrane pump, serves to suck a fluid, such as steam or a steam-water mixture, from the pressure vessel
Data Source
Figure 1~2
AI summary
The invention relates to a steam sterilizer comprising a pressure vessel (2), a first fluid drain line (71) connected to the pressure vessel (2), a second fluid drain line (72) connected to the pressure vessel (2), a vacuum pump (15) which can be brought into flow connection with at least one of the first fluid drain lines (71) and the second fluid drain line (72) and by means of which a fluid can be extracted from the pressure vessel (2), and a feedwater tank (9) which serves to receive feedwater (10) intended for the generation of steam that can be supplied to the pressure vessel (2). According to the invention, the steam sterilizer is characterized in that the first fluid drain line (71) is routed through a first heat exchanger (8, 80) with exclusively indirect heat transfer.wherein a fluid flowing through the first fluid drain line (71) serves as the heat-emitting medium and feedwater (10) serves as the heat-absorbing medium, wherein the first fluid drain line (71) and the second fluid drain line (72) are in flow connection with a second heat exchanger (13) which is arranged downstream of the first heat exchanger (8, 80) in the flow direction of a fluid flowing from the pressure vessel (2) through the first fluid drain line (71), and wherein the steam sterilizer (1, 100) has a third fluid drain line (73) and a fourth fluid drain line (74) downstream of the second heat exchanger (13) in the flow direction of a fluid flowing from the pressure vessel, wherein there is optionally a flow connection between the third fluid drain line (73) and the second heat exchanger (13) or a flow connection between the fourth fluid drain line (74) and the second heat exchanger. (13) can be made or interrupted,that the vacuum pump (15) is arranged in the fourth fluid drain line (74), and that a single feedwater pump (17) is provided for pumping the feedwater (10) in the steam sterilizer (1, 100).