Principle / Features | UVTRON^®: Flame / Discharge sensors

UVTRON® are UV ON/OFF detectors that can quickly detect a flame’s weak UV emission from a distance, making them suitable for flame detectors and fire alarms. They have a narrow spectral sensitivity from 185 nm to 260 nm and are completely insensitive to visible light. They make it possible to design a high-sensitivity, quick-response UV detection system with simple circuitry.

This video shows the operating principle and features of UVTRON that functions as a discharge or flame sensor. Check out this demo video to see what it can really do.

Internal structure

Head-on type
Example: R9533

Side-on type
Example: R2868

Operating principle

When more than a certain amount of UV light enters the cathode (photocathode) through the UV transmitting glass, photoelectrons (electrons) are emitted from the cathode surface due to the photoelectric effect of the electrode material.

The photoelectrons are attracted to the anode side by the electric field energy and collide with gas molecules in the tube as they accelerate, resulting in ionization of the gas molecules.

Electrons and positive ions are generated by the ionization.

The number of electrons and positive ions increases at an accelerated rate as they repeatedly collide with other gas molecules.

When the UVTRON^®-specific discharge conditions are met, a large current flows drastically between the anode and cathode, producing a discharge state.

Features

High sensitivity

UVTRON can detect weak UV light emitted from flames and discharges. This allows accurate detection even at long distances and inside large spaces to provide a greater degree of freedom and flexibility in installation locations.

Distance characteristics (Typ.)

Flame detection from long range

Flame detection for alcohol lamps

Solar-blind spectral response

UVTRON only has a spectral response range between 185 nm and 300 nm and so has no sensitivity in the visible light region. Types using a Ni (nickel) electrode are insensitive even to UV rays from the sun, allowing use not only indoors but also outdoors without requiring optical visible-cut filters.

Spectral response (Typ.)

Fast response

Since UVTRON directly detects UV light emitted from flames or discharges, it can instantly detect flames immediately after ignition or discharges right after these occur. This is difficult or impossible for other methods utilizing smoke or heat sensing to accomplish. UVTRON detects UV light and outputs a signal within a few milliseconds, ensuring a high level of safety and allowing the required action to be taken immediately.

Compact and lightweight

UVTRON is compact and lightweight and easily mounts inside compact detectors. Our wide product lineup allows you to choose exactly the right UVTRON for your application and installation location.

Contact us for more information.

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Principle / Features | UVTRON®: Flame / Discharge sensors

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Internal structure

Head-on typeExample: R9533

Side-on typeExample: R2868