Duplex Basket Strainer

A duplex basket strainer allows continuous process flow
when strainer basket requires cleaning.
Image courtesy Fabrotech

Liquid processing systems of many types and application require protection from particulate matter in the flow path. Often, there are mechanical components that cannot tolerate particulate matter greater than some maximum diameter. Pumps, valves, sensors, and other specialties can experience accelerated wear and tear, even clogging, from particulate matter entrained within the liquid flow.

Once the maximum particulate diameter has been determined for various portions of the system, a plan can be implemented that provides a properly sized and configured device in place to remove particulates larger than the greatest allowable size. It is conceivable that identifiable parts of a system will have differeing protection requirements, resulting in the use of several or many different filtration elements throughout the system. Filtration units can range from very small inline filter units protecting a single instrument, to large centralized high flow rate units protecting extended portions of the system.

A basket strainer will be an appropriate choice for many applications. Coordination of strainer housing connection size and type, along with design flow rate and pressure drop are in order. The materials of construction for the housing, strainer basket and other wetted parts should be evaluated for suitability with the process media. A final consideration is the holding capacity of the strainer basket itself. Too small a strainer will lead to a service frequency for cleaning that can prove cumbersome for operating personnel.

Regardless of the type of strainer or filter used, a key consideration is whether the system can be temporarily shut down, or the filter bypassed, while replacement or cleaning of the filtration element is accomplished. A basket strainer, one of several types of liquid filtration devices, is available in both simplex and duplex variants. A simplex basket strainer functions as a single inline unit, requiring flow stoppage or bypass when the basket becomes clogged with debris. The changeover time may not be long, but some processes cannot tolerate any downtime. A duplex strainer is comprised of two simplex strainers incorporated into a common housing. An inlet chamber and diverting valve selects which strainer basket will process the liquid flow, while isolating the other. Changes in pressure drop through the device can be used to signal when it is time to switch operation between the strainer sections.

Fluid filtration is an important part of keeping a process in operation, reducing wear and tear on piping system components and equipment. Share your process fluid filtration challenges and requirements of all types with application specialists. Leverage your own process knowledge and experience with their product application expertise to develop an effective solution.

Simplex vs. Duplex Strainers For Industrial Liquid Processing

Duplex basket strainer, shown with one basket removed
Courtesy Eaton Friltration

Many industrial and commercial liquid systems have mechanical components that cannot tolerate particulate matter in the liquid. Pumps, valves, sensors, and other specialties can experience accelerated wear and tear due to certain types and sizes of particulate matter.

Good practice dictates that the tolerance of the system for particulate matter should be determined and a properly sized and configured device be put in place to remove particulates larger than greatest allowable size. Considerations for connection size and type, construction material suitability for the process media, flow rate, pressure drop, and filter holding capacity should all be a part of the product selection criteria.

Simplex basket strainer with access cover and basket removed
Courtesy Eaton Filtration

One key element of the selection criteria is whether the system can be temporarily shut down for replacement or cleaning of the filtration element. A basket strainer, one of several types of liquid filtration devices, is available in both simplex and duplex variants. A simplex basket strainer functions as a single unit, requiring flow stoppage when the basket becomes clogged with debris. The changeover time may not be long, but some processes cannot tolerate any downtime. A duplex strainer is comprised of two simplex strainers, incorporated into a common housing, with an inlet chamber and diverting valve that selects which strainer basket will process the liquid flow. Changes in pressure drop through the device can be used to signal when it is time to switch operation between the strainer baskets.

Fluid filtration can be an important part of keeping a process in operation, reducing wear and tear on piping system components and equipment. Share your process fluid filtration challenges and requirements with application specialists, combining your process knowledge and experience with their product application expertise to produce effective solutions.

Filtration Yields Returns By Protecting Fluid Process Lines and Equipment

Duplex Basket Strainer With Diverter Valve
Courtesy Eaton Filtration

Most people think of "industrial" equipment as super heavy duty, virtually indestructible. Those of us responsible for operating and maintaining industrial process equipment recognize that is not the case. Even the most formidable appearing equipment can be crippled if not protected from the insidious effects of particulates.

There are numerous strategies for mediating the impact of particulates on industrial fluid process equipment and systems. The best solutions will be customized for each process, with consideration given to:

• Maximum particle diameter threshold: At some level, particulates may be small enough to preclude damage to the system. Above the threshold level, removal of the particles brings some benefit to process operation.
• Pressure drop associated with any mitigation techniques: Assuming that mitigation will involve the addition of components to the fluid system, minimizing the added pressure drop is advantageous.
• Overall volume of particulate matter to be removed: Most often, mitigation equipment traps and retains particulate matter. The retaining capacity of the unit must match the particulate production rate of the process. Be mindful that certain events, such as routine maintenance or cleaning of process equipment, may produce surges of particulates in some types of systems.
• Location of the filtration equipment: Filtration units must be placed in the process flow upstream of the equipment or system portion to be protected. An additional consideration is a provision for maintenance through placement in a convenient, easily accessible location.
• Filtration equipment materials of construction: The filtration gear must be fabricated of materials compatible with the process media.

I have provided a data sheet below with cutaway illustrations and detailed performance data for one type of filtration unit. This particular equipment is manufactured by the filtration division of Eaton and features a duplex strainer basket arrangement with a diverter valve. The process fluid flows through one strainer, with the other clean and ready to be brought on line when the active basket becomes clogged. When the active basket becomes clogged and pressure drop excessive, the operator moves a lever to divert the flow to the second basket, sealing off the now clogged basket area so that it can be opened and cleaned. This design provides for uninterrupted process operation.

Browse the provided data sheet. You will likely pick up something you did not already know, or get a quick refresh of your technical knowledge. The duplex basket strainer is one type in a wide variety of filtration products available for every conceivable process application. Share your challenges with a product specialist. Combining your process knowledge and experience with their thorough product application expertise will generate great solutions.

Eaton Dual Basket Strainer for Industrial Applications from MSJacobs-Cali