May 23, 2022
4. Tests and Operations Performed in a Vacuum Chamber
All in all, the test chamber has become an essential part of the product's quality and longevity. Their use has enhanced production. Vacuum chambers add another element to product inspection by providing the ability to create a particulate and atmosphere-free environment.
Vacuum chambers are an important part of the testing of spaceflight components and components, necessary to ensure the safety of astronauts. they are also used to provide data regarding everyday products such as food, drugs and chemicals, which is an important function for vacuum chambers.
The benefit of vacuum chambers is their ability to create environmental conditions with variable pressure, humidity, temperature, and radiation to assist the industry in developing and perfecting their products.
4.1. Drying
The number two factor in product spoilage is moisture, which can cause rapid and irreversible damage. To combat this problem, manufacturers place products in a vacuum chamber that immediately and more effectively dehumidifies the water.
The drying method varies depending on the product. More resilient products can be dried very vigorously with rapid vacuum formation, while more sensitive products may require a gentler approach.
4.2. Coating
Vacuum coating or thin film deposition uses a vacuum chamber to apply a thin and stable layer of paint on the substrate surface to protect the substrate surface from wear and reduce efficiency. The thickness of the vacuum coatings varies between 0.25 and 10 micrometers, that is, from 0.01 to 0.4 thousandths of an inch. There are several types of coatings applied using vacuum coating, including PVD, cathode arc, and atomic layer deposition. Vacuum coatings are used by companies, semiconductor manufacturers, medical instrument manufacturers, aerospace and automotive manufacturers.
4.3. Degassing
Vacuum degassing is a method to remove dissolved gases from a liquid by reducing the pressure inside the container with the liquid inside. During the metal manufacturing process, the material can be contaminated with residual gases, which can lead to imperfections and affect the performance of the metal. In the production of molten steel, vacuum degassing is used to remove hydrogen and oxygen from the heated material. By reducing the pressure in the vacuum chamber, the gas becomes less soluble and separates from the molten metal. After the gas is removed, it is ejected from the chamber and the chamber returns to normal pressure.
4.4. Product Testing
Vacuum chambers are capable of duplicating various environmental and atmospheric conditions. When a product is to be used at high attitudes, deep in the ocean, or in outer space, its performance must be tested to ensure its ability to work when being stressed. Vacuum chambers can be set and adjusted for any depth or height to test the limits of a part.
One of the benefits of using a vacuum chamber, over other traditional testing methods, is the amount of time required to complete the test since a variety of conditions and atmospheres can easily be programmed into the chamber. This is especially true for products that will face extreme conditions. It is imperative that they be tested and certified for the safety of those who will rely on them.
4.5. Crystallization
The crystallization process is an example of how vacuum chambers can save time and money. The formation of crystals occurs when the liquid solution leaves behind a solid residue. Under normal and natural conditions, this process takes several hours or centuries. Modern manufacturing does not have time to wait for natural crystallization. The vacuum chamber speeds up the process by removing liquid from saturated solutions leaving behind a crystalline residue. Vacuum drying is one of the simplest ways to reduce the size of crystals and improve their uniformity by reducing the separation effect..
4.6. Distillation
Vacuum distillation (VDU) is performed at a pressure lower than atmospheric pressure, unlike atmospheric distillation. The concept is that compounds boil at lower temperatures when pressure is lowered. Vacuum distillation is capable of separating compounds at lower temperatures due to lower pressure. The important function of the process is to bring the liquid to a boil to produce steam so that the materials in the vapor can be separated. After separation is complete, the separated materials are concentrated and re-liquefied.
4.7. Sterilization
The vacuum chamber is designed to remove all materials, particles, contaminants and other matter in low pressure environments. This process creates a condition that there is no living matter. When moisture and air pockets are removed, it also removes any microbial contamination. In the manufacture of medical devices, before packaging, they are placed in a vacuum chamber under low pressure to remove bacteria, fungi, viruses or other contaminants. This ensures that the device is free of parasites and bacteria before shipping for use.
4.8. Cooling
The use of a vacuum chamber for cooling is the rapid removal of moisture from products with a high water content. When the pressure is reduced, moisture is released to the outside and heat is lost. The reduced pressure, in addition to removing moisture, also takes away energy in the product in the form of heat creating rapid cooling. The vacuum cooling process takes about 15 to 30 minutes. The method of cooling products evenly and evenly, which increases their shelf life. Another benefit of vacuum cooling is its cost effectiveness as it requires much less energy than traditional cooling methods..
5. Vacuum Chamber Design
There are several considerations that have to be explored when choosing or designing a vacuum chamber. The first concern is materials that are capable of withstanding the amount of pressure created. Design flaws can debilitate the ability of the chamber to perform properly and complete its desired function.
A well designed and constructed vacuum chamber is capable of providing accurate and repeatable functions. When examining the available chambers, the things that need to be examined are the shape of the chamber, types of materials, the various structural components, surface finish, and the control mechanism.
5.1. Materials
Most test chambers use the same metals and materials for their construction, which are a steel alloy and stainless steel. Vacuum chambers can be built from a variety of materials due to the nature of how a vacuum is formed. The one guiding rule is that the material has to be able to withstand drastic changes in pressure.
When manufacturers choose the materials to construct a vacuum chamber, they make their decision based on the materials strength, pressure, and penetrability. Unlike environmental chambers, vacuum chambers can be made of glass and plastic as well as aluminum, brass, high density ceramic, and acrylic.
5.2. Shape
In many cases, when people picture a vacuum chamber, they think of the small glass chambers found in classrooms. In the vacuum chamber design stage, after selecting the material, the next choice is the shape of the chamber, which can be vertical cylinder or horizontal cylinder, sphere and cube or rectangular box. This aspect of the decision is determined by the application the chamber will be used for, from product testing to finishing application. In the case of a vacuum chamber in an assembly operation, it must be able to pressurize rapidly between product cycles.
5.3. Structural Components
There are a multitude of structural factors that need to be considered when planning a vacuum chamber as they can be configured in a variety of ways. The essential concern in this aspect of the plan is the stability and resilience of the chamber. Making poor choices can be detrimental to chamber performance.
The structural components of the vacuum chamber do not appear to be important for its performance since they are only auxiliary and auxiliary. Weak hinges of unsuitable materials or poor sealants can affect as well as reduce the life of the vacuum chamber and its performance. Stiffeners, bases, fasteners, hinges and lifting points must be carefully examined and considered in the design of the vacuum chamber.
5.4. Surface Finish
Another, what might seem to be a minor concern, is the finish on the inside of a vacuum chamber. In the past, the finish of a vacuum chamber was not considered to be a crucial design concern. Recent research has proven that the surface finish of a vacuum chamber has a varying effect on the pumping speed depending on the pressure range.
The greatest effect of the surface finish has been found to be more prominent in the higher pressure ranges. The data seems to indicate that to achieve the best performance from a vacuum chamber, it is critical that the interior have a smooth finish and be kept clean.
5.5. Joining
Choosing the correct joining method is important in the prevention of leaks from the chamber. The three most common joining methods are welding, brazing, and gluing.
+ Welding: Welding is the best method for sealing a vacuum chamber and preventing leaks. There are a variety of welding techniques that can be used but must be performed by highly trained welders since welding changes the properties of metals. The types of possible methods are butt, lap, corner, tee, and edge welding.
+ Brazing: Brazing is a method of joining metals by melting a metal into the joint between metals. The metal being melted has a lower melting point than the metals being joined. For this method to succeed, the metals being joined must be strong and ductile. Also, brazing is an expensive method and has to be carefully chosen.
+ Gluing: In the construction of a vacuum chamber, gluing can be a method for joining materials but is only applicable under special conditions. The types of glues would include high performance epoxy for sealing aluminum chambers. The chosen adhesives must be resistant to solvents, lubricants, alcohol, and certain select acids.
5.6. Valves and Gauges
All vacuum chambers are equipped with valves and gauges. Metering valves assist in removing internal particles and moisture as well as providing an inlet for process gases. For safety precautions, vacuum chambers have bleed valves, which protect the chamber and samples. Gauges are necessary for measuring and displaying vacuum chamber pressure.
5.7. Controllers
Much like all testing chambers, there are many choices when it comes to a controller for a vacuum chamber. Some systems are completely manual, which require adjustments and monitoring. Automated controllers allow users to set the parameters of the process. As the procedure unfolds, the system makes adjustments in pressure, temperature, and any other programmed factors.
The automated control system is configurable with customizable software and multiple data acquisition methods. The choice of controller is usually determined by the importance of the application and the size of the vacuum chamber. Smaller chambers may require only a simple gauge to monitor pump and pressure, while larger chambers may require a more complex system.
Conclusion
1. A vacuum chamber removes air and pressure from a confined enclosure to test the effects of a vacuum on parts, materials, components, and assemblies or perform applications for manufacturing operations.
2. In industry, there is a need for high altitude testing, drying, and off gassing in controlled and replicable vacuum conditions and environments. These types of tests assist in establishing the quality and durability of a product.
3. Vacuum chambers are designed to fit the needs of the industries they serve.
4. A vacuum is a space with low pressure where all matter has been removed that could possibly affect the testing or manufacturing process.
5. The benefit of vacuum chambers is their ability to create environmental conditions with varying pressure, humidity, temperature, and radiation to assist industry in developing and perfecting their products.