Optical Liquid Level Switches That Can Be Used in Almost Any Liquid

Optical Liquid Level Switches for Reliable Detection in Almost Any Liquid

Whether you’re monitoring diesel in a construction vehicle, protecting telecom enclosures from water ingress, or preventing a pump from running dry, accurate liquid detection is essential to system safety and performance. SST’s optical liquid level switches offer a dependable solution for detecting the presence or absence of liquid across a wide range of demanding applications.

Built for Versatility

Designed and manufactured in Scotland, SST’s compact, single-point level switches are trusted in industries ranging from heavy machinery to medical devices. With a wide selection of housing materials available—such as Polysulfone, Trogamid®, Tritan™, Stainless Steel, and Glass—our sensors are built to withstand everything from mild process fluids to aggressive chemicals and high temperatures.

Each material offers distinct advantages:

• Polysulfone: Ideal for diesel, methanol, and oil-based liquids.

• Trogamid®: Compatible with harsh solvents like acetone and petroleum oils, and safe for food contact in the EU.

• Tritan™: Approved by both NSF and FDA for medical and food-grade applications.

• Stainless Steel with Glass: Perfect for high-temperature or chemically aggressive environments where plastics would fail.

Simple Operation, Solid-State Reliability

The sensing principle is straightforward and robust. Each switch contains an infrared LED and phototransistor at its tip. In air, the light reflects internally and returns to the detector. When immersed in liquid, the light refracts out of the tip, and the detector sees a drop in signal—indicating the presence of liquid.

Because they have no moving parts, SST’s switches eliminate the mechanical failure points common in float-based designs. They’re immune to foam and small air bubbles, making them more reliable in dynamic environments. Their solid-state nature also allows for rapid detection of even small volumes of liquid with consistent performance over long lifespans.

Application-Proven Performance

These sensors are widely used in:

• Fuel and hydraulic tanks in construction and off-road vehicles

• Outdoor electronics and telecom cabinets where moisture ingress can be damaging

• Medical devices, food-grade machinery, and chemical processing equipment

• Pumping systems where dry-run prevention is critical

The compact size and rugged design make SST’s optical switches suitable for tight spaces and tough environments, while their fast response time adds an extra layer of system protection.

Customisation to Fit Your Needs

At SST, we understand that no two applications are alike. If your project requires something outside our standard offerings, we can customise sensor electronics, housings, outputs, cabling, or connectors to meet your exact specifications. Our engineering team works closely with customers to create bespoke solutions that perform exactly as required.

Need guidance on selecting the right liquid level switch for your application?
Ask the Expert — get in touch at sales@sstsensing.com or call us on +44 (0)1236 459 020.