Liquid Leakage Sensors: Components, Types, Materials and Design Features

Liquid leakage sensors typically consist of:

• Sensing Element or Band: This is the primary component detecting the presence of liquid. Materials vary depending on chemical resistance needed, commonly stainless steel (SUS316), fluoroplastics, or polyethylene coatings for durability and resistance against corrosion and chemicals.
• Signal Processing Unit: Converts sensor signals into readable or actionable outputs, often involving oscillators and detectors applying AC signals to prevent sensor corrosion and ensure stable operation.
• Output Interface: Includes relay outputs, LED indicators, buzzers, or digital communication outputs to notify operators or control systems of leaks.
• Casing and Housing: Designed to protect internal components from environmental damage, often sports an IP67 rating for waterproof and dustproof features. Materials like PFA (perfluoroalkoxy) or fluoroplastic casing resist acidic, alkaline, and corrosive environments.

• Optical (Photoelectric) Leak Sensors: Utilize light reflection principles with LEDs and photodiodes. Detect liquids by changes in reflected light intensity. Suitable for detecting all types of liquids regardless of conductivity. Often no need for sensor adjustment for different liquids. Available in spot-type or sensing cable layouts.
• Conductivity Sensors: Detect leaks by measuring changes in electrical conductivity caused by conductive liquids like water or electrolytes. Common in water leak detection. May face limitations with non-conductive liquids.
• Water Rope or Cable Sensors: Employ water-sensitive cables or ropes laid across areas prone to leaks. Detect any liquid contacting the cable along its length. Used extensively in data centers, industrial facilities, and cleanrooms.
• Probe or Point Sensors: Use metal probes at specific points to detect liquid presence by completing an electrical circuit.
• Thermal or Infrared Sensors: Detect temperature differences caused by leaking fluids. Often used in applications where fluid temperature differs from surroundings.

• Sensing Bands: Stainless steel (SUS316) for strength and chemical resistance or fluoroplastics like PFA for superior chemical and temperature resistance.
• Casing: Materials like fluoroplastic or PFA provide corrosion resistance against harsh chemicals, while standard plastic casings may suffice for less aggressive environments.
• Cable Jackets: Often PVC or FEP (fluorinated ethylene propylene) for chemical and water resistance.

• High Sensitivity and Fast Response: Instant leak detection to minimize damage.
• Wide Chemical Resistance: Sensors designed for corrosive or acidic liquid environments.
• Fail-Safe Functions: Self-diagnostic alarm systems alert for sensor or wiring failures.
• No-Adjustment Operation: Optical sensors often do not require adjustment for different liquids.
• Compact and Robust: Small size for installation in limited spaces, with rugged housing for durability.
• Multiple Installation Options: Ability to install multiple sensors in series or parallel for large area monitoring.
• Waterproof and Dustproof: IP67 rating ensures sensor protection under harsh environmental conditions.
• Built-in Indicators and Alarms: LEDs and buzzer alarms facilitate immediate leak location and status signaling.
• Integration Friendly: Relay outputs, digital communications for easy integration into automation or safety systems.

These design considerations make liquid leakage sensors indispensable for many sectors, including semiconductor manufacturing, medical equipment, industrial automation, data centers, and chemical processing plants.

By selecting the appropriate sensor type, materials, and design features suited for the application environment and liquid characteristics, reliable and fast leak detection can be achieved, safeguarding equipment, reducing downtime, and enhancing safety.