Flow Switch

Features of the Flow Switch are that it senses whether there is any flow of fluid in a pipe line and generates an alarm, controls valves, or stops the machinery once a pre-set flow rate is reached.

The paddle type of action taken in response to flow changes makes the Flow Switch ideal for use in applications involving water circulation, cooling lines, and others that involve liquids.

The Flow Switch also aids in protecting pumps against dry running by sensing low or no flow situation before any damage can be done.

Flameproof models of Flow Switches are also available for hazardous locations.

• Multiple quick-change paddles.
• Snap-acting microswitch for reliable switching.
• Field-adjustable set points.
• Field-adjustable paddle length.
• Stainless steel paddle and shaft construction.
• Durable and reliable performance.
• Suitable for detecting the flow of liquids in pipelines.
• Helps protect pumps, motors, and process equipment against low or no-flow conditions.
• Supports automatic pump sequencing and process control.
• Available in weatherproof and flameproof enclosure versions.

• Fluid: Clear Liquids & Gases
• Specific Gravity: Up to 2.95
• Viscosity: Up to 20 cP
• Design Temperature: Up to 160°C
• Design Pressure: Up to 7 Kg/cm²
• Flow Range: 2.2 to 800 m³/hr (Water/Liquid)

Normal Static Position

When there is no fluid moving through the pipeline, the mechanical assembly remains at rest. An internal spring expands to hold the unit’s permanent magnet downward, keeping it positioned away from an isolated reed contact, maintaining a standard normally open (N.O.) electrical circuit.

Dynamic Flow Displacement

As liquid or gas begins traveling through the line, the media pushes against a custom-sized paddle suspended directly inside the stream. The velocity of the moving medium exerts a physical force on this paddle flow switch mechanism, forcing it to pivot forward at an angle of 20 to 30 degrees.

Magnetic Field Shift

The physical tilting of the paddle acts on an eccentric mechanical linkage inside the housing. This movement pushes the internal magnet upward toward the sealed electrical enclosure, bringing its localized magnetic field close to the embedded electrical switch contact.

Circuit Actuation

Once the magnet reaches its peak position, its magnetic field triggers the internal contacts, instantly snapping the electrical loop into a closed circuit. This positive mechanical action provides essential system feedback, functioning as a dependable flow switch for pump dry run protection or to prevent pump cavitation.

Process Control Signalling

This automated contact closure instantly relays a discrete electrical signal to your connected PLC, control valve, or motor starter. By providing immediate logic feedback, this industrial flow switch protects critical equipment by automatically triggering auxiliary systems or shutting down operations if lines run dry.

Enclosure Types

• Weatherproof Enclosure: Standard housing engineered for outdoor or wet utility tracking.
• Flameproof Enclosure: Explosion-proof housing rated for hazardous chemical and gas zones.
• Weatherproof with Mounting Tee/Flanges: Equipped with pre-assembled integration piping modules.
• Flameproof with Mounting Tee/Flanges: Specialized hazardous area configurations with direct pre-fabricated process mounts.

Line Sizes & Process Calibration

• Line Size Capacity: 25 NB to 150 NB pipelines (with custom paddle trims extending based on exact line diameter).
• Measuring / Actuation Range: 2.2 to 800 M³/hr of Water/Liquid equivalent volume.
• Accuracy Profile: ±1% of Full Scale Deflection (FSD).

Mechanical & Material Options (MOC)

• Wetted Valve/Body Material: Brass or SS316 stainless steel options.
• Paddle & Internal Shaft Elements: Heavy-duty Stainless Steel construction.
• Core Mechanisms: High-endurance internal spring with dual quick-change, field-adjustable paddles.

Pressure & Thermal Ratings

• Maximum Design Pressure: Up to 7 Kg/cm² operating load.
• Maximum Design Temperature: Up to 160°C operational limit.
• Medium Limits: Clear liquids and industrial gases with a specific gravity up to 2.95 and maximum viscosity up to 20 cP.

End Connections & Switches

• Threaded Ports: 1” BSP (M) or 1” NPT (M) options.
• Electrical Contact Modules: Snap-acting microswitch or permanent magnet reed switch with standard Normally Open (N.O.) or custom closed circuit configurations.

Protects Pumps from Damage: The device measures the fluid flow in the pipe and is able to initiate shutdown of the equipment if the flow becomes lower than the necessary one, thus providing protection to pumps.

Assists in Achieving Stable Circulation: Adjustable paddle design, the switch helps to keep the appropriate flow in circulation systems and ensures constant performance of the equipment.

Safe Usage in Hazardous Environments: Special flameproof types of switches with hermetic reed switches are designed for hazardous environments in the presence of flammable liquids or gas.

Long Service Life: The switch made of brass or SS316 has a mechanically simple structure with no electronics inside it, therefore requiring minimum maintenance.