Paddle Flow Switch
A mechanical flow switch with a paddle in the stream that trips a contact when flow rises above or falls below the set point. Sizes ½" to 6", threaded or flanged, to 10 bar and 135 °C, adjustable from 10 to 60 % of maximum flow, with SPDT, DPDT, dry or pneumatic outputs.
Paddle Flow Switch
A paddle flow switch is the simplest protection against loss of flow. A paddle, sized to the pipe, hangs in the stream; flow deflects it and moves a magnet or lever that operates a switch. When the flow falls below the set point the paddle returns and the switch changes state. There is no power to the sensing element and nothing to configure.
Switches are supplied for pipes from ½" to 6" with threaded or flanged connections, at pressures up to 10 bar and temperatures up to 135 °C. The set point is adjustable between 10 and 60 % of the maximum flow for the pipe size, or fixed to order. Wetted parts are carbon steel, AISI 304 or 316, with PVC, Moplen or PVDF for corrosive water. Outputs are relay, SPDT or DPDT microswitch, mercury switch, dry microswitch for low-level signals or a pneumatic switch for control systems without electricity.
Enclosures are available in waterproof and explosion-proof versions, with gold-contact switches for PLC inputs and inductive alarms as alternatives.
Typical duties are pump-running confirmation, cooling-water loss alarms for compressors, furnaces and machines, chiller and boiler flow interlocks, and flow proving in firefighting loops, in HVAC, water systems, industrial cooling and chemical and general process plants.
Flow
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