Automatic Self-Cleaning Strainers
From Automatic Strainers
Widely used in many industries, R.P. Adams patented Automatic Backwash Strainers are a rugged design that provides reliable, efficient, un-attended operation. Also called Automatic Backflush Filters, they remove suspended solids, dirt, and debris from many different water streams and process fluids. The strainers work around the clock with minimal maintenance or operator attention. They provide cost effective continuous protection for downstream equipment, reducing maintenance and downtime for heat exchangers, spray systems, and process equipment.
How They Operate
Straining: The automatic strainers have a circular arrangement of elements mounted to a removable tubesheet. Raw water enters the inlet chamber, passes through the tubesheet, then flows through the elements from inside to outside. Solids are collected inside the elements, and the strained water exits via the outlet.
Backwashing: The automatic strainer stays on stream during the backwash cycle, so flow to the process is not interrupted. A backwash cycle is initiated by a differential pressure switch or an adjustable interval timer. During the short backwash cycle an automatic valve opens, and the backwash drive motor is energized to rotate the internal backwash assembly. The backwash assembly has a hollow backwash arm and shaft. As the backwash arm rotates, a seal plate moves along the inlet side of the tubesheet. Each element is cleaned one at a time in sequence, as a small amount of strained water reverses flow, flushing the collected solids through the backwash valve.
Benefits of R.P. Adams Automatic Backwash Strainers
- Continuous protection of downstream equipment with automatic, un-attended backwash operation.
- Our patented multi-element design provides larger surface area than most automatic strainer designs, with greater solids holding capacity and longer intervals between backwash cycles.
- The strong, corrosion-resistant elements withstand 150 psid differential pressure, collapse or burst. The other internals are also designed to withstand 150 psid dirty pressure drop, protecting downstream equipment from upset conditions.
- The motor driven backwash assembly operates intermittently, saving energy and wear and tear on moving parts when compared to designs that rotate continuously.
- Vertical and Horizontal strainer configurations and flexible Inlet and Outlet flange orientations are offered for most sizes, allowing custom arrangements to accommodate installation requirements.
Summary of Automatic Strainer Features Offered
- Line / Connection Sizes of 4” to 54”.
- 150 GPM to 85,000 GPM flow capacity.
- Wide range of separations: 0.125” to 0.001” wedgewire elements (3200 to 25 µ)
- Design pressure 150 psig is standard for most sizes, up to 300 psig design is available.
- Design & construction per R.P. Adams standard design, or per ASME Code Section VIII or Section III with code stamp. CRN, design / construction per Pressure Equipment Directive (PED), and other international codes are available.
- Materials of construction include cast iron, lined carbon steel, 304L or 316L SS, and super duplex SS. Other materials available upon request.
- Standard automatic backwash controls include control panel, differential pressure switch, and backwash valve.
- Custom controls are available, such as contacts for DCS monitoring or control, alarm contacts, shear key failure detection, PLC control, and special features to meet customer requirements.