Airpower Glossary

Absolute Pressure: The total pressure measured relative to a perfect vacuum, equal to gauge pressure plus atmospheric pressure. For example, standard atmospheric pressure at sea level is about 101.3 kPa (14.7 psi), so a gauge reading of 0 would correspond to ~101.3 kPa absolute.
Aftercooler: A heat exchanger that cools compressed air after the compression stage. By reducing the air’s temperature, an aftercooler causes water vapour to condense into liquid, which can then be removed, helping to dry the compressed air and protect downstream equipment.
Air Compressor: A device that takes in air, pressurises it (reducing its volume), and often stores it in a tank as potential energy to be released as needed. Air compressors convert power (from an electric motor, diesel/petrol engine, etc.) into compressed air used to power tools, inflate tires, or supply industrial pneumatic systems.
Air Dryer: Equipment designed to remove moisture from compressed air, improving air quality and preventing water damage in tools/processes. Refrigerated Air Dryers cool the air to about 3–4 °C so that water condenses out (dew point ~+4 °C under pressure). Desiccant Air Dryers (heatless dryers) pass air through moisture-absorbing desiccant material, often in twin alternating chambers, achieving very low dew points (down to –40 °C or even –60 °C) by adsorbing water vapour. Both types usually include pre-filters (water traps) and after-filters to catch contaminants.
Air Receiver (Tank): A storage tank for compressed air, also called a receiver or air vessel. The receiver acts as a buffer to accommodate demand spikes and helps stabilise pressure in the system. It allows the compressor to cycle on/off less frequently, improving efficiency and ensuring a steady supply of air. Air receivers are rated for maximum pressure (e.g. 1100 kPa or 160 psi) and have drain valves to remove accumulated condensate.

Atmospheric Pressure: The pressure of the surrounding air at sea level (~101.3 kPa or 1.013 bar). It serves as the reference for gauge pressure. Standard atmospheric conditions are often used for defining SCFM (Standard CFM) – e.g. 1 atm at 20 °C. (Absolute pressure = gauge pressure + atmospheric pressure.)

Bar: A metric unit of pressure. 1 bar equals 100 kPa and is approximately equal to 14.5 psi. For reference, typical industrial compressors might deliver 6 to 10 bar (600–1000 kPa) of pressure. In compressed air contexts, “bar(g)” usually means gauge pressure in bar.
Ball Valve (Ball Cock): A shut-off valve that uses a drilled sphere (ball) which can rotate to open or close flow. Ball valves are used on compressed air lines and tanks for isolation and draining. (Important safety note: No shut-off valve should be placed between a pressure vessel and its safety valve.)
Bead Blasting: A form of abrasive blasting similar to sandblasting, but using fine glass beads as the abrasive media. Compressed air propels the beads at a surface to clean or finish it. Bead blasting is gentler than sandblasting and is used for polishing or removing surface deposits without damaging the base material.
BSP: Stands for British Standard Pipe, a thread standard commonly used for fittings in compressed air systems (e.g. ¼″ BSP, ½″ BSP threads on connectors, valves, gauges). Airpower’s safety valves, non-return valves, etc., often specify BSP thread sizes for compatibility. (BSP threads have a parallel or tapered profile and are measured in inches.)

CFM (Cubic Feet per Minute): An imperial unit of volumetric air flow rate, used to rate compressor output and air consumption of tools. It indicates how many cubic feet of air flow per minute. To convert to metric: 1 CFM ≈ 28.3 L/min. For example, a compressor output of 200 L/min is about 7.1 CFM. (SCFM, Standard CFM, means the flow in CFM standardised to certain conditions, e.g. 1 atm, 20 °C.)
Check Valve (Non-Return Valve): A one-way valve that allows air flow in one direction and prevents backflow. In compressors, a non-return valve on the outlet ensures that pressurised air in the tank doesn’t leak back into the compressor pump when it’s off. (No check valve or any restriction should be between the tank and its safety relief, to ensure the safety valve can vent properly.)
Coalescing Filter: A type of air line filter that removes aerosols (fine oil mists and water droplets) by coalescing them into larger droplets. Coalescing filters typically have very fine filter elements (e.g. 0.01 micron) and can reduce oil carryover to extremely low levels (e.g. <0.01 mg/m³). They are often installed before desiccant dryers or at the point of use to ensure high air purity.
Compressor Oil (Lubricant): Specialised oil used for lubricating and cooling compressors. Mineral compressor oils are petroleum-based, while Synthetic compressor oils (PAO, PAG, etc.) offer greater stability, higher flash points and longer life. Oil-lubricated compressors require regular oil changes; using the correct grade (e.g. screw compressor oil vs. piston oil) is important for reliability. (Airpower supplies both mineral and synthetic oils for screw and piston compressors.)
Custom-Built Compressors: Airpower can design and build compressors to unique specifications. This might involve custom tank sizes (receivers), special configurations (e.g. tandem compressor pumps), or integrating additional features. Custom builds are often done to meet particular industrial needs not served by standard models.

Desiccant Dryer: See Air Dryer. A dryer that uses desiccant material (like silica gel or activated alumina) to absorb moisture from compressed air, achieving very low dew points (dry air). Desiccant dryers typically consist of twin towers that cycle: one tower dries the air while the other regenerates (purges moisture), then they swap. Also called twin-tower dryers or adsorption dryers.
Diesel Air Compressor: A portable or standalone air compressor powered by a diesel engine. Diesel compressors are commonly used in outdoor worksites or as backup units (where electric power isn’t available or during outages). They often have fuel tanks and are mounted on skids or wheelbarrow/trolley frames for transport. (Airpower’s diesel models range roughly from 6.7 hp up to 13 hp engines.)
DIY Compressor: A casual term for a small, hobbyist-grade air compressor intended for “do-it-yourself” tasks. DIY compressors are typically lightweight, oil-less or direct-drive units used for occasional air needs (inflating tires, hobby airbrushing, brad nailing, etc.). They are not designed for heavy continuous use – for example, one would not use a cheap DIY compressor for a 100% duty cycle application.
Duty Cycle: The percentage of time an air compressor can run (produce air) versus rest in a given period, without overheating. For instance, a 50% duty cycle means the compressor should run no more than half the time (e.g. 5 minutes on, 5 minutes off in a 10-minute cycle). A 100% duty cycle indicates the compressor can run continuously at its rated output. Heavy-duty industrial compressors (e.g. rotary screws) are often 100% duty rated, whereas small reciprocating/piston compressors may have duty cycles of 50% or less, needing cooldown periods. Selecting a compressor with an appropriate duty cycle is important to avoid motor or pump overheating and premature wear.

Electric Air Compressor: A compressor driven by an electric motor. Electric compressors are common for indoor and stationary use (workshops, factories) because they require no fuel and have no exhaust. They range from small 0.5 kW units up to large industrial motors (22 kW or more in Airpower’s range). Advantages include quieter operation (than engine-driven units) and lower maintenance, as long as an adequate electrical supply is available.
Filter (Compressed Air Filter): A device that removes contaminants from compressed air. Common types include particulate filters (to trap solid particles like dust/rust, often rated by micron size, e.g. 25 μm) and coalescing filters (to remove oil mist and water droplets, often rated 0.1 μm or finer). Filters are usually part of an air prep system and are placed before regulators and lubricators. For example, Airpower stocks standard 25 micron filters as well as finer coalescing and activated carbon filters for oil vapour removal. Regular filter maintenance (draining water, replacing elements) is crucial for keeping air quality high.
Flow (Air Flow Rate): The volume of air delivered per unit time, usually stated in L/min, m³/h, or CFM. It indicates the capacity of a compressor or the demand of a tool. For instance, 1,000 L/min is about 60 m³/h or ~35 CFM. Airpower helps customers calculate the required flow for their applications (e.g. sum of tool consumptions) to ensure the selected compressor can meet the demand.
FRL: Stands for Filter-Regulator-Lubricator, a trio of components often installed together in compressed air lines (sometimes as a combined unit). The filter removes particulates/moisture, the regulator controls pressure, and the lubricator adds a fine oil mist to lubricate pneumatic tools and cylinders. An FRL unit ensures clean, controlled, and lubricated air for downstream equipment, greatly extending tool life and performance.
Full Load: In a compressor context, full load means the compressor is operating at its maximum output (maximum pressure and flow it’s rated for). Running “at full load” continuously corresponds to 100% duty cycle usage. Compressors can also run unloaded or at part load (e.g. when using modulation or variable speed drives) to match air demand.

Glycerine-Filled Gauge: A pressure gauge whose casing is filled with glycerine (or similar liquid) to dampen the vibration of the needle. Glycerine-filled gauges are used in compressor systems to give a steadier, more accurate reading, especially where there is pulsation or vibration. For example, Airpower offers glycerine-filled bottom-entry gauges for compressed air receivers, which maintain clarity even when the compressor is running and vibrating.
Gauge Pressure: The pressure reading relative to ambient atmospheric pressure (as opposed to absolute pressure). Most compressor gauges show gauge pressure – e.g. a reading of 0 bar means the tank is at atmospheric pressure, 7 bar means 7 bar above atmosphere. To get absolute pressure, add ~1 bar of atmosphere. For instance, 7 bar(g) = ~8 bar(abs). Gauge pressure is usually denoted with a “g” (e.g. barg or psig). (In Airpower’s documentation, when they list pressure in kPa, bar, or psi, they generally mean gauge pressure unless stated otherwise.)
Gas Compressor: A broad term for any machine that increases the pressure of a gas by reducing its volume. An air compressor is one example (compressing air, which is a mixture of gases). Other types include refrigerant compressors, CNG compressors, etc. Principles used include positive displacement (pistons, screws, vanes) or dynamic (centrifugal, axial). Airpower focuses on positive-displacement air compressors (piston, screw, vane) for industrial and commercial use

Horsepower (HP): A unit of power commonly used to rate engines and motors. 1 HP ≈ 0.746 kW. In compressor specs, motor power might be given in HP or kW (e.g. a 5.5 kW motor is roughly 7.5 HP). As a rule of thumb, each horsepower of a typical 6–13 bar compressor yields about 100 L/min of air output (similarly, 1 kW yields ~133 L/min, since 1 kW ≈ 1.33 HP). While HP indicates motor size, actual air delivery (CFM) can vary by compressor efficiency.
Humidity Control: In the compressed air context, this refers to managing the moisture content in the air. It involves drying the air and draining condensate. Airpower offers humidity control solutions like refrigerated and desiccant dryers, automatic drain valves, and moisture separators. Proper humidity control prevents water in airlines, which can cause corrosion, malfunction of pneumatic equipment, and poor product quality (for paint spraying, etc.).
Hydrovane: A brand name (Hydrovane) synonymous with rotary vane compressors. Airpower services vane compressors (e.g. Mattei, Hydrovane) in addition to other types. In general usage, “hydrovane” might refer to the vane-type compressor technology, which uses an eccentrically mounted rotor with sliding vanes to compress air. Vane compressors provide steady airflow and are often used in smaller industrial and OEM applications.

Idle Running Governor (Load Genie): A device used on engine-driven (petrol/diesel) compressors to control the engine speed and compressor loading. When set pressure is reached, the idle control (often called a Load Genie or pilot unloader valve) causes the engine to throttle down to idle and unloads the compressor, preventing overpressure. This saves fuel and reduces wear by allowing the compressor to run continuously without building excessive pressure. When air is needed (pressure drops), the governor opens the throttle to power the compressor again. (On small continuous-run compressors, the Load Genie combines a check valve and unloader – sensing flow demand and unloading the pump when no air is being used.)
ISO 8573-1: An international standard specifying quality classes for compressed air (part 1 covers contaminants like particles, water, oil). Airpower’s dryers are said to comply with common ISO 8573-1 compressed air quality classes. For example, a typical requirement might be Class 1.4.1 (which limits particle size, pressure dew point, and oil content). Knowing the ISO 8573-1 class needed for a given application helps in selecting the right filtration and drying equipment.
Isolation Valve: A generic term for any valve (often a ball valve or gate valve) used to isolate a section of the system. For instance, an isolation valve may be placed before and after an air dryer or filter so that it can be serviced without depressurising the whole system. In the diagram above, there are isolation valves around the bypass loop for the dryer. Always ensure isolation valves are open during normal operation and only closed for maintenance or emergencies.

Jackhammer: Slang for a pneumatic demolition hammer (also called a pneumatic breaker). Jackhammers are heavy air-powered tools used to break up concrete, rock, or pavement. They consume a high volume of compressed air (often requiring a large portable compressor on site). For example, a medium jackhammer might require ~100 CFM at 6–7 bar to operate effectively. (Air compressors are frequently used to power jackhammers on roadwork or construction sites.)
Jetting (Air Jetting): Using high-pressure compressed air streams for cleaning or cutting. In some contexts, “air jetting” refers to blowing out pipes or mixing materials with bursts of air. It’s not a specific product Airpower sells, but the concept would utilise the compressed air equipment in their lineup (e.g. using a high-pressure nozzle or an air lance attached to a compressor).

kPa (Kilopascal): A metric unit of pressure. 1 kPa is equal to 1000 Pascals. In compressed air, larger units are used: e.g. 100 kPa = 1 bar. So typical working pressures are 600–800 kPa for many shop compressors (≈6–8 bar). Airpower often lists pressures in kPa alongside bar and psi (e.g. 800 kPa, 8 bar, ~116 psi all represent the same pressure). For reference, atmospheric pressure is ~101.3 kPa (0 kPa gauge).
kW (Kilowatt): A unit of power in the metric system. Used to rate electric motor power on compressors. 1 kW ≈ 1.34 HP. So a 7.5 kW compressor motor is about 10 HP. Airpower’s electric compressor range goes from ~0.37 kW (mini units) up to 22 kW and beyond. Knowing kW helps ensure you have an adequate electrical supply (amperage, phase) to run the compressor. Often, both kW and HP are listed for compressors to cater to different preferences.

Load/Unload: The operating cycle of many compressors, especially piston and screw compressors, is under governor or pressure switch control. Loading means the compressor is actively compressing air (air intake open, pumping into the system). Unloading means the compressor is running but not producing air (intake is restricted or vented, so no new air is compressed). For example, a screw compressor will unload when line pressure is at the setpoint, venting output and perhaps running in idle, then load again when pressure drops. This prevents over-pressurisation and saves energy by avoiding excessive cycling. (The terms “cut-in” and “cut-out” are similarly used for when a pressure switch loads and unloads a compressor at set pressures.)
Load Genie: See Idle Running Governor. (Load Genie is a trademarked name for a kind of unloader check valve used on some continuous-run piston compressors. In colloquial use, any engine-driven compressor unloader could be referred to as a load genie if it functions similarly.)
Lubricator (Airline Lubricator): A device that introduces a fine oil mist into the compressed air stream to lubricate downstream pneumatic components (air motors, cylinders, valves, air tools). It’s the “L” in an FRL unit. The lubricator is usually adjustable – a drip rate can be set so that the correct amount of oil is carried by the airflow. Modern practice sometimes avoids lubricators if using oil-free components, but in many industrial air tool setups, a lubricator greatly extends tool life by reducing friction and wear.

MAM Controller: A specialised electronic controller for compressors (particularly rotary screw compressors). MAM is a brand/model of compressor controller module that Airpower imports and uses on its screw compressor systems. These controllers typically handle functions like start/stop sequencing, safety alarms, phase monitoring, load/unload control, and display the compressor status/pressure. In short, a MAM controller is the “brain” of a modern compressor, ensuring efficient and safe operation.
Micron (µm): A unit of length equal to one-millionth of a meter, used to specify filter pore sizes. In compressed air filters, micron ratings indicate the size of particles the filter will trap. For instance, a 25 micron pre-filter will remove larger dirt and moisture droplets, while a 0.01 micron coalescing filter will remove very fine oil mist. Smaller micron rating = finer filtration. However, finer filters create more pressure drop, so systems often use a series (e.g. 5 µm then 0.1 µm) for efficiency.
Minimum Pressure Valve: A valve typically found in oil-flooded rotary screw compressors (usually in the separator tank outlet) that maintains a minimum internal pressure in the system. The minimum pressure valve (MPV) stays closed until a threshold (e.g. ~4–5 bar) is reached in the compressor. This ensures proper oil circulation (oil is injected and needs a certain pressure to return) and also prevents the system air from flowing back when the compressor is unloaded. Once pressure exceeds the set minimum, the MPV opens to deliver air to the plant. It also functions as a check valve when the compressor stops, keeping the system pressurised and oil in place.
Moisture Trap (Water Trap): A device or filter designed to remove condensed water from an air line. Often, it refers to a cyclonic separator or drop-out filter that uses centrifugal action to fling water droplets out of the air stream into a bowl. For example, a pre-trap before an air dryer will spin out the bulk of liquid water so it doesn’t enter the dryer. A moisture trap typically has an automatic drain to periodically expel the collected water. It’s essential because even aftercoolers and receiver tanks can’t remove all moisture, traps placed at low points in the system will catch what condenses out downstream.

Non-Return Valve: See Check Valve. (Non-return valve is another term for a check valve, emphasising its function of not allowing return flow. In compressor systems, the non-return valve between the pump and tank keeps the tank air from pushing backwards into the compressor. Airpower lists various sizes of non-return valves, e.g. ½″, ¾″ BSP, etc., to fit different compressor outputs.)
NPT: Though not explicitly in the Airpower text, NPT stands for National Pipe Taper, an American thread standard similar in use to BSP. Many compressors and pneumatic tools in South Africa might use BSP fittings, but being aware of NPT (often found on US-made equipment) is useful. (Included here for completeness, as fittings are sometimes labelled BSP/NPT for compatibility notes.)

Oil Carryover: The amount of lubricating oil that passes downstream into the compressed air output. In oil-lubricated compressors, some fine oil mist usually escapes with the air. This is measured in mg/m³. A good coalescing filter can reduce oil carryover to extremely low levels (e.g. 0.01 mg/m³). Oil carryover is a concern for air used in painting, instrumentation, or food processing. Regular maintenance of separators and filters helps minimise carryover.
Oil Separator (Air-Oil Separator): A filter element usually found inside rotary screw compressors (oil-injected type) that separates the oil from the compressed air before the air exits to the receiver. The air-oil mixture from the screw airend is forced through the separator element (which looks like a canister or cartridge) – the oil coalesces and is recovered to the oil circuit, while the dry air goes out to the tank. A properly functioning separator keeps oil consumption low (typical carryover may be 1–3 mg/m³ if in good condition). Airpower sources, separators (and other filter elements) for many brands of compressors. A clogged separator will cause high pressure drop and oil carryover, so it should be replaced as per service schedules.
Overload (Thermal Overload): In electrical compressors, this refers to the protection device that trips if the motor draws too high a current or overheats. For instance, Airpower’s three-phase pressure switches with overload have integrated thermal overload relays. If an overload trips, it stops the compressor to prevent motor damage. It usually needs to be manually reset once the issue is resolved. Always investigate the cause of an overload (could be low voltage, jammed pump, etc.).

Petrol Air Compressor: An air compressor powered by a petrol (gasoline) engine. Similar in application to diesel compressors, petrol-driven units are often portable. They are used by contractors, emergency services, or as standby units when electricity is unavailable. Petrol compressors in Airpower’s range span roughly 5 HP to 30 HP engines and can provide compressed air for tasks like tire inflation on service vehicles or powering nail guns on construction sites.
Pneumatics: The branch of technology or engineering that uses compressed air (or other gases) to transmit force and do work. Pneumatic systems include components like cylinders (actuators), valves, air motors, and control assemblies. Airpower deals extensively in pneumatics – for example, they distribute Camozzi pneumatic components and repair all types of pneumatic equipment. In everyday terms, pneumatic refers to anything operated by air pressure.
Pneumatic Cylinder: A mechanical device (actuator) that converts compressed air pressure into linear motion (extension/retraction). It consists of a piston and rod moving inside a tube. When air is fed into one side of the piston, it pushes the rod out (or pulls it in for double-acting types). Airpower, as a Camozzi agent, can assemble and supply pneumatic cylinders quickly (even custom stroke lengths). These are used in automation for pushing, clamping, lifting, etc.
Pneumatic Solenoid Valve: An electrically controlled valve that directs air flow in a pneumatic circuit. The solenoid coil shifts the internal spool of the valve, opening or closing ports. For example, a 5/2 solenoid valve will control a double-acting cylinder’s extension and retraction by switching the airflow. Airpower’s pneumatic solenoid valves are marketed for precise and reliable control of automation systems. They are available in various configurations (voltages, port sizes, flow rates).
Pressure (Working Pressure): The operating pressure of a compressed air system, often expressed in bar or psi. Common shop air pressure is around 6–8 bar (90–120 psi). “Working pressure” implies the pressure at which tools or processes are meant to run. Airpower recommends setting the compressor output pressure a bit above the highest required working pressure, then using regulators at points of use to dial down to the exact needed pressure. Ensuring the compressor can maintain the working pressure at the required flow (CFM) is critical for system performance.
Pressure Dew Point: The dew point temperature of air at a given pressure. Compressed air at line pressure has a higher dew point than the same air at atmospheric pressure. For example, refrigerated dryers deliver air with a pressure dew point of around +3 to +5 °C at 7 bar. That means if that air expands to atmospheric pressure, its dew point would be lower (because at atmospheric pressure it can hold less moisture without condensing). Desiccant dryers achieve pressure dew points of –40 °C or lower, meaning the air is extremely dry (no condensation until the air is very cold). Monitoring dew point is a way to measure air dryness (often required by ISO 8573-1 classes).
Pressure Regulator: A device that reduces and maintains the air pressure to a set level downstream, regardless of fluctuations in the supply pressure or flow demand. It typically uses a spring and diaphragm mechanism: you turn a knob to compress a spring, which sets the outlet pressure. In use, if downstream pressure exceeds the setpoint, the regulator closes; if it drops, the regulator opens to allow more air through. Airpower’s product line includes stand-alone regulators and combo filter-regulators. Regulators are vital for protecting tools (most air tools have a max PSI) and stabilising process pressure (like paint spray consistency).
Pressure Switch: An electromechanical switch that monitors pressure in the compressor tank and controls the motor accordingly. When pressure drops to a preset cut-in level, the pressure switch turns the compressor on; when pressure rises to the cut-out level, it turns the compressor off. For example, a typical setting might be cut-in at 6 bar, cut-out at 8 bar. Pressure switches often have an adjustment range and some differential (hysteresis) between cut-in and cut-out. They can be single-phase or three-phase; some include an unloader valve port to release head pressure on shutdown, and some three-phase models include an overload relay for motor protection. In essence, the pressure switch automates the compressor’s start/stop to maintain the desired tank pressure.
Portable Air Compressor: A compressor designed for mobility – usually smaller units with handles or wheels (like wheelbarrow-style or cart-style frames). They can be electric or engine-driven. Portable compressors are used for jobs like construction, DIY, or service calls (tyre inflation, running a nail gun, etc.). Airpower offers portable & mini compressors that are compact and lightweight. Even larger diesel trailer compressors fall in the “portable” category if they can be towed or easily moved. The emphasis is on convenience and flexibility of location, albeit usually with a trade-off in capacity compared to stationary industrial compressors.

Reciprocating Compressor (Piston Compressor): A compressor that uses a piston moving back and forth (reciprocating) in a cylinder to compress air. These can be single-stage (one compression step) or multi-stage (multiple cylinders compressing in series for higher pressures). Piston compressors are common in workshops, garages, and smaller industrial setups. They deliver pulsating air flow and typically have higher noise and vibration than rotary screws, but are economical and straightforward. Airpower builds and repairs many piston compressors – their airpower-branded units come with cast-iron pumps and are tested before delivery. Key characteristics: need an air receiver to even out the flow, often oil-lubricated (some small ones are oil-free), and the duty cycle is often <100% (they need cooling pauses).
Rotary Screw Compressor: A compressor that uses two intermeshing helical rotors (screws) to compress air continuously. The male and female rotors trap air in cavities and reduce the volume as the screws turn, delivering a steady, non-pulsating air flow. Screw compressors are known for their 100% duty cycle capability (they can run continuously) and relatively quiet, smooth operation compared to piston compressors. They are oil-injected in most industrial designs (oil seals, cools, and lubricates the rotors), then an air-oil separator removes the oil from the output air. Airpower’s screw compressors are used in 24/7 industrial applications and come with features like phase protection and advanced controllers. A major benefit of rotary screws is their efficiency and lack of valves – meaning fewer vibration-inducing forces and often lower maintenance on valves/gaskets. They excel in supplying large volumes of air, e.g. for factory airlines or large pneumatic tools.
Rotary Vane Compressor: A type of positive-displacement compressor with an off-centre rotor and sliding vanes. As the rotor spins, centrifugal force pushes the vanes out against the casing, trapping air in compartments that get smaller, thus compressing the air. Vane compressors deliver steady flow and are generally quieter than piston types. They often have a simpler design with fewer moving parts than screws (no timing gears, for example). Brands like Hydrovane/Mattei produce these. They are used in applications requiring reliability and simplicity, like elevator shaft brake systems, small factories, and OEM machine integration. Airpower services vane compressors (as noted in their brand list: Mattei, Hydrovane, etc.). Maintenance typically involves vane replacement after a certain amount of wear and keeping the oil clean, but no pistons or valves to overhaul.

Sandblasting: The process of blasting abrasive sand (or similar grit) at high speed using compressed air to clean or etch surfaces. It requires a strong air supply – typically a high CFM compressor (often portable diesel units on job sites for blasting large structures). Sandblasting is used for cleaning metal (rust/paint removal), engraving stone, or preparing surfaces for painting. Airpower even markets compressor setups for sandblasting & bead blasting service in Cape Town. One must use proper moisture separators and aftercoolers when sandblasting, as wet air can clog the blasting media. (Also, appropriate safety and dust collection are critical due to the hazardous dust generated.)
Safety Valve (Pressure Relief Valve): A fail-safe valve on a pressure vessel or system that automatically opens to vent air if pressure exceeds a set threshold, preventing explosions or damage. Airpower recommends sizing a compressor tank’s safety valve to discharge at least 25% more flow than the compressor’s maximum output. The safety valve should be set slightly above the normal working pressure (typically ~10% higher) and must release 110% of that pressure. For example, if a compressor is set to cut out at 8 bar, a safety valve might be set to 8.5 bar. It’s vital that nothing (no shutoff valves) obstructs the safety valve’s connection to the vessel. Regular testing or replacement of safety valves is important to ensure they function in an emergency. (They often have a manual test ring to pull and verify operation.)
SCFM: See CFM. Standard Cubic Feet per Minute – similar to CFM but specified at standard conditions (often 1 atm, 20 °C, 0% relative humidity). It’s a way to compare flow rates independent of actual operating pressure and temperature. In context, if an Airpower compressor is rated, say, 10 CFM, that usually implies ~10 SCFM at standard reference conditions. If the air is delivered at higher pressure, the actual volume flow in free air terms might differ, but SCFM normalises it. (This term wasn’t explicitly in the site text, but it’s commonly used in compressor specs and good to know.)
Separator: In general terms, this could mean a moisture separator or an oil separator. We covered the Oil Separator above. A moisture separator is essentially a water trap or cyclone that “separates” liquid water from air. In Airpower’s diagram, for instance, there is an oil separator (in the compressor), and after the aftercooler, there might be a moisture separator/filter. Context is key: “separator” on its own in the compressor world often refers to the air-oil separator element.
Spray Gun: A tool that uses compressed air to atomise and spray paint or other fluids. Airpower lists spray guns under accessories. These require dry, regulated air to avoid water or oil in the finish. HVLP (high volume low pressure) spray guns, for example, might run at ~2 bar but require a lot of airflow. In a glossary context, it’s enough to know that a spray gun is an air-powered painting device. (Airpower also sells paint pressure pots to feed spray guns for larger jobs.)
Star-Delta Starter: An electrical starter for larger three-phase compressor motors (typically above ~7.5 kW) that reduces inrush current. It starts the motor with windings in “star” (Y) configuration, which gives lower voltage per phase, then after a brief period switches to “delta” for full power. Airpower includes Star/Delta starters with their 11 kW and 15 kW compressor models. The transition happens automatically a few seconds after startup. This soft-start method prevents tripping breakers and reduces mechanical stress. (By contrast, smaller motors use a Direct-On-Line (DOL) starter, which connects full voltage immediately – simpler but with higher starting current.)
Synthetic Oil: In compressor terms, a man-made lubricant (PAO, esters, etc.) designed to outperform mineral oils. Synthetic compressor oils can handle higher temperatures and often allow longer service intervals. For screw compressors, synthetic oil is common to manage the heat of compression and resist varnish formation. Airpower offers synthetic oils for both screw and piston compressors. When switching to a synthetic, one typically drains the mineral oil and sometimes changes separators/filters, as the synthetic can clean out deposits (which might clog filters initially). The benefit is generally extended compressor life and efficiency.

Tank: Common term for the air receiver. (See that entry under “A”.) In everyday language, one might say “the compressor’s tank is 200 L”, meaning the air receiver capacity. The tank stores compressed air and helps even out pressure fluctuations.
Thermal Protection: Many electric compressors have a thermal cutoff or thermal protection on the motor (either a built-in thermal switch or an external overload relay). This will stop the motor if it overheats. It’s often manually reset. Ensuring proper ventilation around the compressor and not exceeding its duty cycle can prevent thermal trips.
Tire Inflator: A device for filling tires with compressed air, usually consisting of a pressure gauge and a trigger valve with a hose and chuck. Airpower includes tire inflators in their accessories (often combined with a blow gun or in kits). It’s a staple tool in any garage or service station, using around 0.5–1 CFM each time you fill a tire (but requiring short bursts of air).
Two-Stage Compressor: A reciprocating compressor with two compression stages, typically used to achieve higher pressures. For example, Airpower’s Type 30 two-stage pumps compress air in one cylinder, pass it through an intercooler, then compress it further in a second cylinder. This allows reaching pressures of 10–15 bar more efficiently than a single stage. Two-stage units are characterised by having one larger first-stage piston and a smaller second-stage piston (often with an intercooler tube between them). They provide higher pressure at a given HP, and run cooler on each stage than if one stage tried to do it all.

Ultra Filter: Refers to an ultra-fine filter, typically meaning a very high-efficiency coalescing or adsorption filter for compressed air. Airpower lists “Ultra filters” under Filters, likely meaning filters that remove extremely fine oil aerosols or odours (possibly down to 0.003 mg/m³ oil content or with activated carbon for odour removal). These are used when air needs to be nearly oil-free (such as for breathing air or food packaging). They usually come after a coalescer and dryer in the air treatment train.
Unloader Valve: A valve that releases pressure from the compressor head and lines when the compressor stops or idles. In piston compressors, the unloader is often part of the pressure switch or pilot mechanism – it “bleeds off” the pressure in the pump discharge line when the motor shuts off, so that the next start is unloaded (no backpressure). In continuous-run systems (with idle control), an unloader stays open to atmosphere when the target pressure is reached, preventing further pressure build-up. Essentially, unloaders disconnect the compressor from the system pressure. Without an unloader, a compressor would struggle to restart against full tank pressure. (Note: On small home units, you might hear a hiss for a few seconds after the motor stops – that’s the unloader valve releasing the head pressure.)
Unit of Measure (Units): In the compressed air context, key units include pressure (bar, psi, kPa), flow (CFM, L/min, m³/h), volume (litres or gallons of tank size), power (HP, kW), and temperature (°C for dew point, etc.). It’s important to convert units correctly: Airpower often provides both metric and imperial in specs (e.g. 500 L tank ~ 132 gal; 7 bar ~ 102 psi). Familiarity with these units helps in interpreting compressor performance data and requirements.

Vacuum Pump: A device that removes gas molecules from a sealed volume to create a partial vacuum (negative pressure relative to the atmosphere). While not compressing air to above atmospheric pressure, vacuum pumps are the inverse – they “suck” air out of a space. Airpower manufactures electric vacuum pumps (including piston and screw type vacuum pumps) mainly for applications like hospital suction systems and industrial processes. The vacuum level is often measured in mbar or as a percentage of full vacuum. For example, a pump might achieve 95% vacuum (meaning 5% of atmospheric pressure remains). Vacuum pumps often look like compressors, and in fact a compressor can be adapted to run as a vacuum pump in some cases (by altering the intake). Airpower’s range includes Type 30 vacuum pump blocks and custom builds with receivers for vacuum.
Vertical Receiver: An air receiver oriented vertically. Airpower offers vertical air receivers (tanks) as well as horizontal. Vertical tanks save floor space and are common in systems where the footprint is limited. Functionally, they do the same job of storing air. One consideration is drainage: vertical tanks make it easier for condensate to collect at the bottom drain. Many larger compressors (especially those above 500 L) use vertical receivers to minimise footprint.
VSD (Variable Speed Drive): A technology for compressors where the motor speed is controlled by a frequency inverter (variable-frequency drive) to adjust the compressor output to match air demand. Although not explicitly mentioned in the text, one of the Airpower product snippets references “VSD drive” on a USAir screw compressor. A VSD compressor can save energy by reducing motor speed during low demand (thus reducing airflow and power consumption rather than unloading and running at full speed no-load). They also provide softer starts and maintain a more stable system pressure. VSD is typically found on rotary screw compressors for industrial use.

Water Trap: See Moisture Trap. (A simple wording variant – water trap refers to any separator or trap installed to catch water. Often, this might be a bowl with an automatic drain at low points in the system or after an aftercooler. Airpower’s literature on dryers explains using a cyclonic filter as a water trap before the dryer to remove liquid water that would otherwise overload the dryer.)
Working Pressure: The pressure range at which a system is intended to operate. For example, a compressor might have a working pressure of 7 bar, meaning it maintains around 7 bar in the system (with cut-in/cut-out around that). Components are usually rated by maximum working pressure (e.g. a hose might be rated for 10 bar working pressure). It’s good practice to set your compressor output a bit above the highest working pressure needed, then regulate down at the point of use. Airpower stresses choosing the correct compressor such that it can supply the volume (CFM) at the required working pressure, since the needed pressure and volume together dictate the power and size of the compressor required.

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