Trim to size Paddle Flow Switch

The FSW301 flow switch comprises a paddle system with a permanent magnet attached. Above that magnet is a reed contact, located outside the flow of fluid. A second magnet with opposing poles creates the force necessary to reset the switch back to the no flow position.

When the monitored flow pushes the paddle and changes the position of the magnet in relation to the reed contact it activates the contact. As soon as the flow is interrupted, the paddle moves back to its starting position, which returns the reed contact to the initial position. The force necessary to push the magnet back is provided by the two magnets repelling each other. Using magnetic force instead of the usual leaf spring means the switch is considerably more stable in the long term and much less sensitive to pressure peaks.

The reed contact used as a sensing element consists of two ferro-magnetic contact blades located in a glass bulb filled with inert gas. This practically eliminates wear resulting from contact burning. This construction allows a useful life of up to 100,000,000 switching cycles.

Specifications and Dimensions

Maximum Pressure: 25 bar Maximum Process Temperature: 110°C Maximum Ambient Temperature: 80°C Protection Class: IP65 Process Connection: ½" BSPP Male Maximum Switching Current: 1 A Maximum Switching Voltage: 230 Vac, 48 Vdc Maximum Switching Capacity: 26 VA, 20 W Set Point Tolerance: ±15% Plug Connector: DIN 43650 socket. Materials of Construction: Body: Brass Paddle System: Polypropylene, Noryl Shaft: Stainless steel

Pipe Size mm Paddle Trim Setpoints (Horiz. Pipe. Water 20°C)† Max. Flow Rate lpm (m³/h) Paddle Mark Insertion Length (L3) mm Increasing Flow lpm (m³/h) Decreasing Flow lpm (m³/h) 20* 9 40 18.3 (1.1) 15 (0.9) 66 (4) 25* 15 46 21.7 (1.3) 18.3 (1.1) 83 (5) 32* 20 51 31.7 (1.9) 26.7 (1.6) 133 (8) 40* 30 61 35 (2.1) 30 (1.8) 166 (10) 50* 40 71 45 (2.7) 40 (2.4) 233 (14) 80* 60 91 85 (5.1) 78.3 (4.7) 500 (30) 100** 80 111 106.7 (6.4) 96.7 (5.8) 666 (40) 150** 80 111 258.3 (15.5) 236.7 (14.2) 1666 (100) 200** 80 111 500 (30) 483.3 (29) 3000 (180) * Requires Installation into 'T' Fitting to EN 10242 ** Requires Installation into ½" BSPP Socket, Length 15mm to EN 10241 †Insertion into vertical pipes possible, set points on request