The Towa Seiden DPL-100 Rotary Paddle Level Switch (Model: DPL-100 DC24V Type) manufactured by Towa Seiden Industrial Co., Ltd. (Japan) is an industrial point level detection instrument engineered for modern automated processing plants. The defining architectural characteristic of the DPL-100 compared to the classic PRL-100 Series is its dedicated 24V DC power supply execution. Operating on safe extra-low voltage (SELV), the switch integrates directly into standardized 24VDC control circuits of PLCs, safety relays, and distributed control systems (DCS) without requiring hazardous 110V/220V AC auxiliary power lines or bulky external voltage transformers.

Mechanically, the Towa Seiden DPL-100 features a standardized Japanese industrial flange connection conforming to JIS 5K65A (cast aluminum alloy or optional SUS304 stainless steel), providing rigid structural stability for horizontal side-wall or vertical top-cover mounting on storage silos and hoppers. Both the drive shaft and the standard W-1 paddle blade (80 x 80 mm) are precision-fabricated from SUS304 (AISI 304) stainless steel, delivering superior abrasion resistance against abrasive media while preventing cross-contamination in plastics, food, or chemical applications.

The operational mechanism of the Towa Seiden DPL-100 utilizes an electromechanical torque-reaction principle with integrated motor overload protection:
- Under unconstrained conditions (when bulk material has not reached the sensing paddle): An internal low-speed DC gear motor continuously turns the shaft and paddle assembly at approximately 1 revolution per minute (RPM).
- When bulk material rises and restricts paddle rotation: The mechanical resistance exerted by the surrounding pellets or powder stops the paddle. The resulting reactive torque causes the suspended motor assembly to rotate slightly around its axis, tripping an integrated SPDT microswitch (rated 250V AC, 5A / 30V DC, 3A) to transmit high-level or low-level interlocking signals to the host PLC; concurrently, a secondary contact cuts electrical power to the drive motor. By de-energizing the motor while the paddle remains stalled in material, coil overheating and burnout are entirely prevented.
- When the material level falls (releasing the paddle): A precision return spring pulls the motor assembly back to its starting position, resetting the SPDT microswitch contacts and restoring DC electrical power to resume paddle rotation.

The upper housing is cast from high-pressure aluminum alloy (ADC12) with an industrial protective finish and sealed to an IP65 ingress protection rating. Immune to airborne dust, electrostatic charges, and dielectric variations of process media, the Towa Seiden DPL-100 provides dependable, maintenance-free performance across automated material handling lines.

• Manufacturer: Towa Seiden Industrial Co., Ltd.
• Country of Origin: Japan
• Complete Part Number: Towa Seiden DPL-100
• Product Category: DC 24V Industrial Rotary Paddle Level Switch
• Nominal Supply Voltage: 24 V DC (Permissible voltage tolerance ±10%)
• Power Consumption: Approximately 2.0 W to 3.0 W
• Paddle Rotational Speed: Approximately 1.0 RPM
• Operating Principle: Electromechanical torque-reaction with automatic motor cut-off
• Electrical Output Contact: 1 SPDT microswitch (Single-Pole Double-Throw)
• Contact Rating: 250V AC, 5A (Resistive load) / 30V DC, 3A
• Detectable Bulk Density: From 0.2 g/cm³ or greater (High-sensitivity multi-vane paddle options available)
• Mechanical Process Mounting: Standard Flange JIS 5K65A (Outer diameter ~155 mm, 4 bolt holes)
• Standard Immersion Length (L): 150 mm (Measured from flange face to paddle tip) or extended options (200 mm, 300 mm, 500 mm)
• Standard Paddle Geometry: W-1 single-vane paddle (Blade dimensions: 80 x 80 mm) in SUS304
• Wetted Materials:
  - Shaft and Paddle: Stainless Steel SUS304 (AISI 304) or optional SUS316
  - Mounting Flange: Aluminum casting or optional SUS304
  - Shaft Seal: Abrasion-resistant Nitrile rubber (NBR) oil seal / packing seal
• Terminal Housing Material: Heavy-duty aluminum diecast (ADC12)
• Process Vessel Operating Temperature: -10°C to +70°C
• Ambient Enclosure Operating Temperature: -10°C to +55°C
• Maximum Process Operating Pressure: Up to 196 kPa (approx. 2.0 bar / atmospheric pressure)
• Ingress Protection Rating: IP65 (per IEC/EN 60529 standard)
• Net Product Weight: Approximately 3.2 kg (depending on immersion stem length)