In order to navigate the world of vacuum science, a specialized vocabulary has evolved to help professionals navigate the unique nuances, equipment, and applications of the niche market. As someone interested in perusing or purchasing vacuum components, it is necessary to arm yourself with the appropriate knowledge to differentiate between products to choose the right one for your application.
As a trusted vacuum manufacturer for almost 60 years, ANCORP is committed to providing high-quality products and empowering our community with knowledge. In this comprehensive glossary, we break down the terminology that defines the world of vacuum technology.
| Analytical Instrumentation | Any device or appliance that measures the composition, structure, or properties of a substance. Vacuum is used in analytical instruments such as mass spectrometers, chromatographs, electron microscopes, and particle accelerators to create low-pressure environments for accurate analysis and observation of samples. | |
| ASA Flange System | Standardized by the American Standards Association (ASA), this flange system consists of two flanges, a sealing ring, and bolt fasteners to compress the seal between the two flanges. A pair of ASA flanges must have one grooved flange to accept the sealing ring and one smooth-faced flange onto which the seal will be made. | |
| Base Pressure | The pressure at which the system reaches equilibrium between effective pumping speed and total gas load. In other words, the chamber is giving off as much gas as the pump is evacuating. | |
| Bakeout | Thermal treatment processes performed in vacuum systems to remove volatile contaminants, moisture, or trapped gasses from surfaces and components. During a bakeout, the vacuum chamber is heated to elevated temperatures (typically between 100°C and 200°C or higher) for a duration dependent on application. The heat causes the contaminants to vaporize and desorb from the surfaces, which are then removed from the system by the vacuum pumps. Bakeouts are essential for achieving and maintaining ultra-clean and low-pressure environments in vacuum systems, particularly in applications such as semiconductor manufacturing, thin film deposition, and space simulations. | |
| Ball Valve | An isolation valve consisting of a body, stem, ball, and flanged end caps machined from corrosion-resistant stainless steel, used to stop or start the flow of process fluids where installed. | |
| Bell Jar | A transparent, bell-shaped vessel used in laboratory experiments to create a vacuum environment for studying physical and chemical phenomena, can be constructed from Pyrex® and metal. | |
| Bellows | Flexible, accordion-like components that allow for expansion, contraction, and movement in various mechanical systems, often used in vacuum systems as a stiffer alternative to flexible metal hose. | |
| Burst Disk | A system safety device designed to rupture at a specific pressure range to protect equipment from over-pressurization. The burst disk membrance is scored to prevent fragmentation on rupture, protecting personnel and system surfaces. | |
| Butterfly Valve | An inline valve installed in a straight section of tubing utilizing a circular plate, or flapper, that rotates around an internal axis to regulate flow. Commonly used as vacuum control valves, isolation valves, or both. | |
| CF (Conflat) Flanges | Ultra-high vacuum flanges with a knife-edge sealing surface providing high integrity and reliability. When used with metal seals, ConFlat flanges can reliably reach temperatures up to 450° C. | |
| Conductance | A measure of the geometric limit with which a gas can flow through a component or system, typically measured in terms of volume per unit time. Taking advantage of fittings such as conical reducers and isolation valves such as ball valves can increase conductance and, therefore, improve system efficiency. Here, theory of conductance can only apply to fluids in a state where they have a relatively lengthy mean free path, which all but necessitates those fluids be gases or plasmas. This also means conductance theory can only be applied in molecular flow. | |
| Cryopump | A type of vacuum pump that operates at very low temperatures, typically using liquid nitrogen or helium to condense and trap gas molecules. | |
| D.N. (Diameter Nominal) | Specifically the maximum diameter of a tube to be used in a given flange, according to ISO standards. | |
| Electrical Feedthroughs | Hermetically sealed feedthroughs designed to pass electrical signals or power through vacuum walls, available in various configurations, voltage, and amperage ratings. | |
| Electron Beam Welding | In this welding process, a high-energy electron beam is used to create a localized weld between metal parts in a vacuum environment, resulting in precise and high-quality welds with minimal distortion. | |
| Environmental Testing | Vacuum chambers are used to subject materials, components, and systems to extreme low-pressure conditions for environmental testing, including thermal vacuum testing, altitude simulation, and vacuum leak testing. | |
| Evacuation | The process of removing gas molecules from a sealed volume or chamber to create a vacuum. | |
| Extreme High Vacuum | A vacuum regime with pressures typically below 10−12 torr, typically requiring special materials and techniques to achieve and maintain. Materials suitable for XHV must undergo firing processes such as vacuum firing or air firing for multiple days at temperatures up to 960° C to ensure minimum outgassing rates. | |
| Feedthroughs | Hermetically sealed electrical, fluid, or motion manipulation components used to pass cables, wires, or tubes through vacuum walls without breaking the vacuum seal. | |
| Fittings | Components used to connect vacuum tubing, hoses, or other vacuum components, including elbows, tees, crosses, and adapters. | |
| Fluid Feedthroughs | Feedthroughs designed to pass fluids or gasses through vacuum walls, commonly used for cooling, heating, or gas applications. | |
| Flow Regime | A way to classify the behavior of molecules defined by their interactions with the environment and other molecules, i.e. turbulent flow, laminar flow, and molecular flow. | |
| Freeze Drying | A preservation technique for foods, pharmaceuticals, and biological materials that removes moisture from substances by freezing them and then subjecting them to vacuum conditions, allowing the frozen water to sublime directly from solid to vapor. | |
| Gaseous Diffusion | The process by which gas molecules move from an area of higher concentration to an area of lower concentration through a permeable membrane or barrier, driven by differences in pressure or concentration gradients. This is applicable during hydrogen degassing and vacuum firing, since hydrogen is drawn out of the steel. | |
| Gate Valve | A type of valve that uses a flat or wedge-shaped gate (a movable barrier) to control the flow of fluid. The gate moves up and down perpendicular to the flow direction to either block (closed position) or allow (open position) the passage of fluid. Gate valves are known for their minimal pressure drop when fully open, making them suitable for on/off control rather than flow regulation. | |
| Gauges | Instruments used to measure and display the pressure within a vacuum system, providing vital feedback for controlling and monitoring vacuum levels including thermocouple gauges, ionization gauges, and capacitance manometers. | |
| Getter | A material placed within a vacuum system to absorb or react with residual gasses, maintaining the purity of the vacuum environment. | |
| High Vacuum | A vacuum environment characterized by very low pressures, typically below 10^-3 Torr, often used in scientific research, semiconductor manufacturing, and space simulations. | |
| Inline Valve | A type of valve that is installed directly in a straight section of tubing, allowing for control of fluid flow without changing the flow direction. Inline valves are often used for straightforward flow control and can come in various types, such as ball valves and butterfly valves. | |
| Ion Pump | A type of vacuum pump that uses electrically charged ions to capture and remove gas molecules from a vacuum chamber. | |
| ISO-K and ISO-F Flange System | The International Organization for Standardization (ISO) flanges provide a complete range of fittings to mount with tubing sized 1/2 inch up to 20 inches in diameter. The flange system consists of two sexless, 360° rotatable flanges, a centering ring for alignment and support of the sealing ring, and a fastener to compress the seal between the two flanges. ISO-QF, ISO-KF, and ISO-NW styles flanges are different abbreviations for the same connection style characterized by the use of quick seal clamps as fasteners. The ISO Large Flange, ISO-LF, style is known as ISO-K and uses claw clamps as a fastener. When bolts are used as ISO large flange fasteners, the sealing style is referred to as ISO-LFB or ISO-F. ISO flange sizes reference the inner diameter in millimeters of vacuum tubing. An ISO flange size chart can be found at https://ancorp.com/product-category/iso-qf-lf-kf-nw-iso-k-flanges-fittings/flanges/ |
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| Isolation Valves | Valves used to stop the flow of a fluid, typically for maintenance or safety purposes. They isolate a section of the system without affecting the rest. | |
| Leak Rate | The rate at which gas molecules enter or exit a sealed volume, measured in units such as millibar-liters per second (mbar·L/s) or standard cubic centimeters per minute (scc/min). | |
| Leak Valve | A precise valve used to control very low flow rates, often in vacuum systems to admit small amounts of gas. Most commonly used in material science, chemical vapor deposition, and spectroscopy applications. | |
| Linear Motion Feedthroughs | Feedthroughs designed to provide linear motion through vacuum walls, used for sample translation, scanning, or positioning applications. | |
| Load Lock | An intermediary chamber that can be evacuated independently of the main chamber or the rest of the system. This allows independent pump down of a smaller volume when having to bring it up to atmosphere, increasing efficiency and reducing downtime. | |
| Low Vacuum | A vacuum environment characterized by higher pressures than high vacuum but lower than atmospheric pressure, typically in the range of 1 to 10^-3 Torr, used in various industrial and laboratory applications. | |
| Mass Spectrometer | An analytical instrument used to identify and quantify the chemical composition of substances based on the mass-to-charge ratio of their ions, often used in vacuum environments for gas analysis. | |
| Material Science Research | Vacuum is utilized in laboratories for studying the properties of materials under low-pressure conditions, including surface analysis, crystal growth, and spectroscopy experiments. | |
| Mean free path | The average distance a molecule travels between collisions with other molecules, relevant in understanding gas behavior at different vacuum levels. As the pressure of a system decreases, the mean-free path of a molecule increases; there are fewer molecules and thus fewer chances at collision. | |
| Medical Device Manufacturing | Vacuum technology is employed in the production of medical devices such as catheters, implants, and diagnostic equipment, including processes such as sterilization, packaging, and coating. | |
| Metal-on-Metal Seals | Metal-on-metal seals are sealing mechanisms used in vacuum systems to create a hermetic seal between three metal surfaces. These seals are typically formed by mating two carefully machined metal surfaces under high compressive forces and squeezing a softer metal gasket between them, resulting in intimate contact between the mating surfaces. Metal-on-metal seals are commonly used in ultra-high vacuum (UHV) and extreme-high vacuum (XHV) applications where leak-tight seals are essential. They offer excellent reliability, durability, and resistance to temperature and pressure variations as seen in ConFlat and Wire Seal flange assemblies. | |
| Micron | A unit of length equal to one-millionth of a meter, commonly used to measure the size of particles or the level of vacuum in vacuum systems. | |
| Molecular Flow | A flow regime where molecules interact with the walls of their system more often than with other molecules present in their environment; flow behavior is influenced more by the physical construction of the system than other flowing molecules. This flow regime occurs when the mean free path is significantly larger than the diameter of the tube through which it travels, or its geometric equivalent. | |
| Oil Diffusion Vacuum Pump | A pump that creates a vacuum by capturing gas molecules via imparting momentum to them with a high-speed jet of vapor or oil. This jet is heated and diffuses from the nozzles in the center of the pump. The jet and any trapped molecules then come in contact with the cooled pump body and lose the energy to desorb back into the system. | |
| Outgassing | A release of adsorbed molecules from the interior surface of a vacuum system. When system pressure reaches the vappor pressure for an adsorbed molecule, it has a tendency to desorb from the surface. Outgassing can be facilitated by elevated temperatures as seen during bakeouts, thereby removing a portion of the total gas load and allowing the system to maintain a lower base pressure. Outgassing is typically measured in units such as Torr liter per centimeter squared per second, or Torr-Liter/cm^2-s. Effectively, it’s the leak rate over a given surface area. | |
| Pendulum Valve | A valve used in semiconductor manufacturing and vacuum technology, featuring a pendulum-like mechanism that swings to open and close the valve port. | |
| Poppet Valve | A valve with a movable element (poppet) that lifts to open and seals against a seat to close, commonly used in engines and hydraulic systems. | |
| Pressure | The force exerted per unit area, typically measured in units such as Pascals (Pa) or millibar (mbar), which describes the describes the amount of gas or fluid still present within a system. | |
| Pumps | Equipment used to create and maintain vacuum environments, including turbo pumps, ion pumps, diaphragm pumps, and rotary vane pumps. | |
| Residual Gas Analyzer (RGA) | A device used to measure and identify the composition of gasses within a vacuum system. It typically operates on the principle of mass spectrometry, where gas molecules are ionized, and the resulting ions are separated based on their mass-to-charge ratio. This allows for the detection and quantification of various gas species present in the vacuum. RGAs are crucial for monitoring vacuum conditions, identifying contaminants, and ensuring the integrity of the vacuum environment, especially in high and ultra-high vacuum systems. | |
| Rotary Motion Feedthroughs | Feedthroughs designed to provide rotational motion through vacuum walls, used for sample manipulation, stirring, or positioning applications. | |
| Rotary Vane Vacuum Pump | A type of positive-displacement pump that uses rotating vanes to create a vacuum by compressing gas molecules and expelling them from the pump. | |
| Rough Vacuum | A vacuum range from atmospheric pressure down to 10−3 torr, often achieved using mechanical pumps. | |
| Seals | Materials or components used to create airtight seals within vacuum systems, including O-rings, gaskets, copper seals, and other metal seals. | |
| Semiconductor Manufacturing | Vacuum is used in various stages of semiconductor fabrication, including deposition of thin films, etching, and ion implantation, to create precise and uniform layers of materials on semiconductor substrates. | |
| Space Simulation | Vacuum chambers are used to simulate the low-pressure and temperature conditions of outer space for testing spacecraft components, materials, and systems in a controlled environment. | |
| Sputtering | A process used to deposit thin films of material onto a substrate by bombarding a target material with high-energy ions or plasma in a vacuum chamber. | |
| Thin Film Deposition | In this process, vacuum is used to deposit thin layers of materials onto substrates, typically for applications in electronics, optics, and coatings. Vacuum coating and deposition techniques include physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). | |
| Torr | A unit of pressure used to measure pressure, particularly in vacuum systems, equal to approximately 1/760th of an atmosphere. | |
| Traps | Devices used to capture and remove contaminants or unwanted gasses from vacuum systems, including cold traps, ion traps, and molecular sieve traps. | |
| Turbo Vacuum Pump | A high-speed rotating pump that generates a vacuum by transferring gas molecules to the pump’s exhaust at high velocities. The many blades in the turbomolecular pump impart momentum to the particles away from the chamber, similar to a diffusion pump. | |
| Ultra-High Vacuum (UHV) | A vacuum level with pressures below 10−9 torr, requiring specialized design considerations extending into pumps, sealing methods, and bakeouts. This vacuum level is applied in spectroscopy, microscopy, nuclear physics, and thin film growth techniques such as molecular beam epitaxy (MBE), atomic layer deposition (ALD), physical vapor deposition (PVD) and chemical vapor deposition (CVD). | |
| Vacuum Chambers | Enclosures from which air and other gasses are removed to create vacuum conditions for experiments, processes, or storage of sensitive materials, available in standard or custom sizes and configurations including spherical, cylindrical, and box. | |
| Vacuum Coating | Vacuum coating involves depositing thin layers of materials onto substrates for applications such as reflective coatings, anti-reflective coatings, and decorative finishes, often used in automotive, optics, and electronics industries. | |
| Vacuum Desiccators | Airtight containers used to store moisture-sensitive materials under vacuum conditions, preventing moisture ingress and degradation. | |
| Vacuum Drying | A drying technique that removes moisture or solvents from materials under vacuum conditions, accelerating the drying process and reducing the risk of thermal degradation. | |
| Vacuum Filtration | A filtration technique used to separate solids from liquids or gasses by applying a vacuum to force the liquid or gas through a filter medium, trapping the solids. | |
| Vacuum Flanges | Connectors used to join vacuum components, chambers, or pipes together, providing a sealed interface while allowing for easy assembly and disassembly of vacuum systems. | |
| Vacuum Furnace | A furnace designed to heat materials in a controlled environment with low gas pressure or a vacuum, enabling precise heat treatment, brazing, or sintering processes. | |
| Vacuum Hardware | Miscellaneous components and accessories used in vacuum systems, including clamps, bolts, nuts, washers, and centering rings. | |
| Vacuum Impregnation | A process used to fill porous materials with a liquid or resin under vacuum conditions, improving their mechanical strength, durability, or resistance to moisture. | |
| Vacuum Insulation | Insulating materials or techniques used to minimize heat transfer and maintain low temperatures within vacuum systems, improving energy efficiency and performance. This technology can also be seen used commercially, like in a thermos. | |
| Vacuum Leak Detection | Techniques and methods used to identify and locate leaks in vacuum systems, ensuring their integrity and performance. | |
| Vacuum Metallurgy | Vacuum is employed in metallurgical processes such as melting, casting, and refining metals and alloys under controlled atmospheric conditions to minimize oxidation, gas inclusion, and impurities. | |
| Vacuum Ovens | Ovens designed to heat materials under vacuum or low-pressure conditions, enabling precise drying, curing, or degassing processes. | |
| Vacuum Pressure Units (e.g., Pascal, Bar) | Various units of measurement used to quantify vacuum pressure, including Pascals (Pa), millibars (mbar), and Torr (mmHg). | |
| Vacuum Pump | A device used to remove gas molecules from a sealed volume, which creates a vacuum by decreasing the pressure within the chamber. | |
| Vacuum Pump Oil | Specialized oils used as lubricants and sealants in vacuum pumps, providing smooth operation and maintaining airtight seals within the pump. | |
| Vacuum Pumps | Including rotary vane pumps, diaphragm pumps, turbo pumps, and scroll pumps, used to create and maintain vacuum environments in various applications. | |
| Vacuum Research | Scientific investigations and studies conducted in vacuum environments to explore phenomena such as gas dynamics, surface interactions, material properties, and particle physics, contributing to advancements in numerous fields. Modern advancements in research and development across many fields of science are empowered by vacuum technology. | |
| Vacuum Robot | An automated system or robot designed to perform tasks in vacuum environments, such as material handling, assembly, or inspection, without human intervention. | |
| Vacuum Science | The interdisciplinary field of science that studies the behavior, properties, and applications of vacuum environments, encompassing physics, chemistry, engineering, and materials science. | |
| Vacuum Seal | A barrier used to prevent the ingress or egress of gasses into or out of a vacuum system, ensuring the integrity of the vacuum environment | |
| Vacuum Switch | A switch or sensor designed to detect changes in vacuum pressure within a system and trigger corresponding actions, such as activating alarms, controlling pumps, or initiating processes. | |
| Vacuum System | A collection of components, including pumps, chambers, valves, and gauges, designed to create and maintain a vacuum environment for specific applications. | |
| Vacuum System Maintenance | Regular upkeep and servicing of vacuum equipment and components to ensure optimal performance, reliability, and longevity of vacuum systems, including tasks such as cleaning, lubrication, and calibration. Frequency is application-dependent and relies on a series of factors such as process tolerance, vacuum level, heat exposure, and more. | |
| Vacuum Technology Applications | The diverse range of practical uses and applications of vacuum technology across various industries and fields, including but not limited to manufacturing, research, healthcare, and aerospace. | |
| Vacuum Valves | Devices used to control the flow of gas into or out of a vacuum system, allowing for the isolation, venting, or regulation of pressure within the system. | |
| Vapor Pressure | The pressure exerted by a vapor in equilibrium with its liquid or solid phase at a given temperature, often measured in units such as Pascals (Pa) or millimeters of mercury (mmHg). A liquid subjected to a pressure below that of its vapor pressure will evaporate readily. | |
| Viewports | Windows or ports installed on vacuum chambers or components for observing processes or samples inside the vacuum system. | |
| Viewport Shutters | Protective covers for observation windows (viewports) in vacuum systems, preventing contamination and damage when not in use. | |
| Virtual Leak | A virtual leak is a volume of gas that is isolated from the main system by a path with very low throughput capability or conductance. Weld pockets and internal, non-vented screws can cause this. | |
| Viscous Flow | A flow regime where gas flows as we would expect a fluid to flow; bulk fluid has inertia and the mean free path is extremely small relative to the diameter of the tube through which it travels, or its geometric equivalent. |