A basket filter is a device that uses a mesh screen to filter out the foreign matter in horizontal pipes. These particles are then removed from the filter and do not enter downstream equipment such as pumps, valves and traps. Read below to learn more about basket filters, how they work, and how to choose the best filter for your application.
How a Basket Filter Works
Basket filters are installed to protect equipment from damage caused by harmful debris that may be present in the piping. Unwanted debris may be dirt or other foreign particles entering the process fluid. Typically, basket filters are installed in horizontal pipes and where high flow is required.
These filters are installed upstream of equipment such as pumps, control valves and traps to prevent potentially corrosive or damaging debris from entering the pipeline. They can be installed individually or in series for added filtration. They may have a single chamber (single filter) or multiple chambers (multiple filters). To learn more about the differences between simplex and duplex filters, check out this article.
Understanding grid sizes
Each filter is designed with a mesh-lined basket to filter and collect unwanted debris. The choice of grid size should be based on the job function, not the size of the system. Choosing a mesh with too small openings may result in more frequent plugging of lines, while a mesh with much larger openings may allow more unwanted debris to flow through pipes and equipment. Ideally, you'll want to choose a mesh that has perforations slightly smaller than the smallest particles you need to filter out.
Mesh size is measured by the number of openings on a one-inch screen. For example, a 16 mesh screen has 16 openings per inch, while a 100 mesh screen has 100 openings per inch. Therefore, higher numbers are able to filter out smaller particles with a finer weave. Baskets are usually made of stainless steel for quality and durability.
Factors in Choosing the Right Basket Strainer
Different basket filters may be required for each application. Before deciding on a filter, consider the unique capabilities of the pipeline. Important factors include line pressure and temperature requirements, type of fluid flow (corrosive, abrasive, etc.), debris size, and frequency of cleaning and maintenance. You might also consider a duplex basket filter (like these), which has two filter baskets fed by a diverter valve. The system allows one basket to be cleaned and serviced, while the other keeps flowing.
How to Maintain a Basket Strainer
Unlike filters that must be replaced periodically, basket filters can be used continuously, as long as they are properly cleaned and maintained. In high flow systems, maintaining pressure is key to the proper functioning of the pipeline. Installing pressure gauges on either side of the basket strainer can alert you to a possible blockage in the piping. An increase in pressure in the filter indicates that the filter needs to be removed and cleaned. Failure to maintain the filter can cause severe blockages requiring filter replacement, so be sure to monitor pressure closely.
Regardless of pressure readings, regular cleaning is recommended to ensure filter life. It is important to note that you must depressurize the line before removing and cleaning the basket filter, as servicing the pressurized filter may result in personal injury or equipment damage. After removing, rinse the filter and soak in cleaning solution. Scrub with a brush as needed and avoid letting the debris harden on the wire. To avoid a complete system shutdown, you may need to use an extra screen during the cleaning process.
Advantages of Using Basket Strainers
Installing a basket filter into a piping system keeps downstream equipment safe from harmful and potentially damaging debris. Choose a mesh size slightly smaller than the particles you are filtering to ensure that any foreign particles are trapped in the basket. You also need to consider other factors, such as temperature and pressure requirements, and the type of liquid or gas passing through the basket filter. Be sure to maintain your basket filter by checking the pressure regularly and scheduling regular cleanings. This small investment will have a lasting impact on downstream equipment.
