Filtration, abbreviated as FLTR, is a mechanical process to separate solids from liquid or gas. This can be accomplished by gravity or vacuum, where the solids pass through a medium letting only the liquid or gas through. The finer the medium, the cleaner the result. Filtration is the first part of the process. The second is the collection of the separated material, which can either be disposed of or used for another purpose.
Nomenclature & Symbols
- A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z
- Absorption - The process of a fluid being taken into the pores of the media.
- Aerosol - A dispersion of small liquid particles in a gas.
- Air filter - A device for removing particulate material from an airstream.
- Atmospheric pressure - The pressure exerted upon the earth's surface by the air because of the gravitational attraction of the earth.
- Backwash - The upward flow of water through a resin or filter bed in the water treatment process. It is used to cleanse, expand and regenerate the resin or filter bed.
- Blinding - The loading up of the filter medium so as to reduce filtration efficiency.
- Cake - The layer of solids deposited in the filter medium during the clarification of a slury.
- Cake release - The ability of a filter medium to allow clean separation of the cake from the medium.
- Calendered cloth - Cloth that has been passed through a pair of heavy rollers to reduce the thickness of the cloth or to flatten the intersections of the wires and provide a smooth surface.
- Capacity - The amount of containment that will be collected on a filter before specified restriction level is reached.
- Carbon filter - An air purifier using activated carbon as the air cleaning agent for the removal of gaseous contaminants.
- Cartridge filter - Consist of multiple cylindrical tubes mounted on holders in a pressure tank. The holders seal the ends of the tube so the water must pass through the walls of the cartridges.
- Cellulous media - A filter material made from plant fiber.
- Check valve - These valves are designed to allow the process fluid to flow in only one direction to prevent backflow.
- Cleaning capacity - An air cleaner must constantly re-circulate indoor air in order to effectively reduce concentrations of airborne particulate contamination.
- Cleanroom - A room/facility in which the air supply, air distribution, filtration of air supply, materials of construction, and operating procedures are regulated to control airborne particle concentrations to meet approperate cleanliness levels.
- Clean zone - A defined space in which the concentration of airborne particles is controlled to specified limits.
- Contaminant - Any foreign or unwanted substance which can have a negative effect on system operation, longevity, or reliability.
- Diatomaceous earth filter - Made up of multiple leaf filter screens mounted on a shaft in a horizontal cylindrical tank. Flow is from both sides of each leaf into collector channels leading to the center of the shaft.
- Discharge - The liquid that leaves the filter after passing through the filter medium.
- Downstream pressure - The pressure exiting the outlet side of the heat exchanger.
- Effective area - The total area of the filter media exposed to fluid flow.
- Efficiency - Is expressed in percentage and always less than 100%.
- Element - A porous device that performs the actual process of filtrarion.
- Emulsion - A suspension of small liquid droplets within a second liquid that will not mix.
- Filter life - The duration, time or volume, that a filter can operate effectively between replacement and/or cleaning.
- Filter medium - A porous sheet capable of passing liquid through while retaining solids by means of mechanical separation.
- Fluid pressure - Fluid at rest, exerts a force perpendicular to any surface in comes in contact with.
- Gasket - A seal between two components, usually bolted.
- HVAC - Used in both residental and commercial systems to controll air quality, humidity, and temperature in indoor spaces.
- Inlet pressure - See upstream pressure
- Kinematic viscosity - The ratio of dynamic viscosity to density or the resistive flow of a fluid under the influance of gravity.
- Laminar flow - Generally happens when dealing with low Reynolds numbers in pipes. This could be due to low velocities, large diameters or high viscosities.
- Line pressure - The pressure in the supply line.
- Media filter - A mechanical filter is a vertical cylindrical vessel that contains some sort filter media. In the oil patch, this will be one to several layers of sand, gravel and/or crushed anthracite. It may also use walnut shells for the filtration media.
- Organic contaminant - Carbon-based chemicals, such as solvents and pesticides, which enter water through cropland runoff or discharge from factories.
- Outlet pressure - See downstream pressure
- Particulate - Solid material suspended in water.
- Permeability - The quality of the soil to enable water to move downward through the soil.
- Pottable water - Denotes whether water is suitable for human consumption.
- Precoating - The operation of depositing on inert material prior to beginning filtration.
- Pressure - It is the force exerted perpendicular to the surface of an object and is expressed as force per unit area.
- Pressure differential - The pressure difference between two points of a system.
- Pressure loss - The difference in pressure between two points, usually caused by friction resistance in the pipe, but moisture can also affect it.
- Scale - Rust or corrosion products adhering to the inner surfaces of pipe. It can decrease the ability to transfer heat and increase the pressure drop for flowing fluids.
- Sediment - Matter present in a water supply, commonly diry or sand, that enters the water due to aging pipes.
- Specific gravity - The density or ratio of any substance to another substance. It sometimes may be called just gravity or relative density.
- Strainer - A closed vessel that collect solid particles to be separated while passing a fluid through a removable screen.
- Supply air - A mixture of re-circulated air and outside air which has been conditioned and delivered to the space.
- Surface loading - The accumulation of collected dust on or close to the upstream surface of filter media.
- Surface media - Filter medias that are thin, cellulosic, microfiber or membrane material and, due to construction, generally provides high flow rate, low pressure rate, and high efficiency, ...
- Suspended solids - This figure is the sum of all of the suspended material found in a water sample or process stream.
- Tackifier - A substance applied to filter media to increase the retention of dust.
- Temporary strainer - A startup strainer, also known as a witch’s hat or conical strainer, in installed in a system to remove unwanted debris from the process stream.
- Thermal sealing - A method of joining two or more layers of media together using heat.
- Tracer gases - Compounds such as sulfur hexafluoride, which are used to identify suspected pollutant pathways and to quantify ventilation rates.
- Two-stage air cleaner - A dust removal system for intake air with a built-in pre-cleaner and an element.
- Turbidity - The cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye.
- Turbulent flow - The flow rate at which laminar flow is exceeded and filtration performance is adversely affected.
- Underrating - Operating a filter at less than manufacturers stated cfm capacity.
- Uniform density - Having the same weight per unit volume of filter media from the upstream (influent) to the downstream (effluent) side of the filter.
- Unitary filter - Individual filters when joined with others of the same type, form a filter bank.
- Upstream pressure - The pressure entering the inlet side of the heat exchanger.
- Velocity - The rate of change or displacement with time.
- Ventilation - The introduction of outdoor air into a building by mechanical means.
- Ventilation rate - The rate at which outdoor air enters and leaves a building.
- Water based - A coating in which the film forming ingerdients are dissolved in or suspended in a volatile system containing water as the major solvent.
- Water desalination - The process of removing salt from water for agriculture and to provide drinking water.
- Water hammer - Occurs when a valve is suddenly opened or closed.
- Water Hardening - Process of hardening high carbon steels by quenching in water or brine, after heating.
- Water softener - Used to remove dissolved minerals from water. Hard water can leave mineral scale after evaporation.
- Water treatment - The manipulation of incoming water to make it suitable for the intended purpose.
- Zone - The occupied space.