Strainers and filters are sometimes overlooked, but they play an important role in keeping damaging debris out of your system. They protect sensitive components such as pumps, valves, lines, and instruments, and they can even help improve the performance of your heat transfer fluid. Below is a short overview of the main types to consider.

Strainers

Strainers generally use wire mesh elements to capture debris from the fluid and protect essential parts of the system, including pumps, valves, and piping. They are typically less expensive than filters and provide the minimum level of protection you should have in place. Most heat transfer system manufacturers include strainers as part of their equipment, with “Y” and “basket” styles being the most common.

“Y” strainers, named for their distinct shape, are frequently used in hot oil systems to remove larger debris. As the fluid flows through, particles settle into the bottom of the strainer while the fluid continues through the mesh. Their compact design and ability to be installed either horizontally or vertically make them especially useful in smaller systems where space is limited.

Basket strainers are larger, hold more debris, and typically cause less pressure drop than “Y” strainers. They are also capable of managing higher flow volumes.

Depending on your needs, either type of strainer is effective for removing larger debris. However, if the goal is to capture finer particulates, a filter is the better choice.

Filters

Filters are designed to remove small particles from the fluid, essentially conditioning it to improve performance and enhance heat transfer. Elements for filters come in a wide variety of materials such as metal, cotton, polyester, pleated metal mesh, or wound fiberglass.

Configurations vary based on the application, operating temperature, flow rate, and system pressures. Filter elements are capable of removing particles down to about three microns when required.

There are two main filter configurations: side-stream and in-line.

Side-stream filters are independent filtration units that operate continuously but usually filter only about 10–20% of the system flow at one time. Over time, they gradually remove fine particulates and condition the fluid, though they do not directly protect system components.

In-line filters, also known as full-flow filters, remove 100% of the system flow. They not only improve fluid quality but also safeguard sensitive equipment. Because they must handle full flow rates, they are generally larger in size. Applications such as blow molding benefit greatly from in-line filters, since their small lines and orifices make them vulnerable to even very small particles.