To properly install a filtration unit in a facility, we need to know some fundamental operating parameters. This will allow us to select the equipment with the most suitable operational characteristics for the application.
The most important parameters to consider are:
Pressure
The pressure at which the filter must operate will largely determine its design features, as well as the type of process connection to be used.
Generally, we divide pressure into three ranges:
- Low pressure < 40 bar
Recommended connections are threaded ends or flanged connections. - Medium pressure < 100 bar
Recommended connections are flanged or weldable. In some specific cases, depending on the size of the unit, threaded connections may be acceptable. - High pressure > 100 bar
For pressures exceeding 100 bar, welded connections are recommended. Flanged connections can also be used, but they are not recommended.
Temperature
The required operating temperature will determine the appropriate filtering medium and housing. Generally, non-metallic materials can only work below 100°C, while metallic materials have a much wider operating range, typically from -29°C to 400°C.
Stainless steel can operate at temperatures up to -200°C, making it suitable for cryogenic services or very harsh conditions.
However, in some cases, it will not be the material of the housing or the filtering element that determines the temperature limit for the equipment’s use, but rather the seals. The seals are the weakest element of all components and can ultimately limit the operational range of the equipment.
Flow rate
The available flow rate in the pipeline where the unit is installed will largely determine the size of the equipment to be installed. The equipment must be properly sized to avoid blockages (if undersized) or incorrect operation (if oversized).
Pressure differential or pressure drop
This concept refers to the difference between the input pressure and the output pressure of the equipment, caused by the obstruction the filtering medium creates as the fluid passes through it. As the filter element becomes clogged, this value increases due to the reduced surface area available for fluid passage.
It is recommended to establish parameters that indicate when this obstruction poses a risk to the equipment and installation, so that cleaning and maintenance can be performed appropriately.
Viscosity
Viscosity is also a parameter that influences the selection of the appropriate filter. The higher the fluid’s viscosity, the more difficult it is for it to pass through the filtering medium. This results in a pressure difference or pressure drop in the equipment.
Properly sizing the equipment and selecting an appropriate filtering medium are parameters that are influenced by the fluid’s viscosity.
Compatibility
When selecting the appropriate material for the equipment and filtering element, it is also necessary to analyze whether it is compatible with the fluids it will handle, in addition to considering the pressure and operating temperature.
Corrosion that a unit may suffer due to low compatibility with the working fluid can lead to malfunction and, especially, a significantly shorter lifespan than expected.
Mesh Size / Filtration Grade
Mesh size or filtration grade refers to the size of the openings present in the filtering element that allow the fluid to pass through. Thisvalue, expressed in mm, microns, or mesh, determines the filtration size that the filtering element allows.