always a reliable solution

Besta AG produces components in the field of level detection and control. The Trimod'Besta Level, Flow, Pressure and Temperature products are developed and produced in Uster - Switzerland. Its can be used for applications from -196°C to +400°C, from vacuum to 320 bar process pressure and low density applications.

Trimod Besta Level switches

Frequently used on off-shore rigs, in steam boilers and plants, power stations, chemical and petrochemical engineering, heating and refrigeration, i.e. airconditioning technology. Made possible by the 3-modular concept:

Switch modules

● Switching elements: microswitches and proximity switches
● SPDT microswitch with silver contracts and 2xSPDT (SIL 1 and SIL 2)
● Pneumatic with ON/OFF output
● Pneumatic with proportional output
● Housings made of aluminium and CrNiMo
● High and low temperature versions
● IP65 to IP68 protection
● Explosion proof versions
● elf lifting terminals for perfect connections

Flange modules

● Stainless steel 1.4408 square flange, 92 mm pitch circle diameter
● EN/DIN, ANSI, BS and JIS compliant industrial flanges
● Special flanges with 98, 105 and 114 mm pitch circle diameter
● Fixed flanges made of CrNiMo
● Composite flanges made of P265GH (Carbon steel) and CrNiMo (316 equiv.)
● Special flanges made of Hastelloy
● DN 65 to 150, 3" to 6"
● PN 16 to 320, class 150 to 2500, table E to T, 5K to 63K
● Flat seal, tongue and groove, ring joint etc.

Float modules

● Fixed switching distance 12 mm
● Adjustable switching distance for pump control, vertical max. 2840 mm, horizontal max. 557 mm
● CrNiMo and Hastelloy stainless steel floats
● NACE compliant floats
● Plastic floats made of PP, PVDF and PTFE
● Stainless steel versions up to a maximum operating pressure of 250 bar
● Float modules for separation layer monitoring
● Stainless steel floats with polyamide and halar coating


 Standard electric

Standard pneumatic

Vertical installation





Industrial range

Flameproof range for Zone 1 or Zone 0





High-temperature up to 400°C

Low-temperature down to -196°C




 Plastic range  Plastic high-temperature up to 200°C  Accessories



Application examples

Limiting maximum/minimum

Pneumatic closed loop control

Open loop control for values pumps and valves

Vertical installation

 Limitation of separation layers

 External fill level monitoring


Optoelectronic Level Sensors

These robust and highly reliable level sensors use the optical principle. The opto-electronic sensor contains an infrared LED and a light receiver. It the liquid level rises in the container and surrounds the tip, the light beam is interrupted by the liquid and no longer reaches the receiver, or only reaches it weakly, causing the latter toreact to the change and to intiate a switching operation.

Used in plant engineering and the chemical and pharmaceutical industry, as well as in mechanical engineering, hydraulics and water technology for liquid such as oils, water, distrilled water, aqueous media, as well as for foam detection.

Limit value switch Optical level limit switch The smallest optoelectronic switch Compact and economical optoelectronic switch


BLS Level Sensor

The BLS Trimod'Besta Level Sensor is universally suitable for level detection and a real alternative to the tuning fork. It works in liquids of all kind, foams, bulk goods, granulates, even in liquids that are sticky, pasty and regardless of their viscosity.

On-site calibration is not necessary and the highly accurate sensor can be installed in any position. It has a very attractive, compact design and is completely maintenance free.  Powered via an M12 connector it communicates its output status through a highly visible blue LED.

● One sensor detects different media (liquids, bulk goods, foams: sticky, pasty or high or low viscosity)
● Maximum temperature stability and repeat accuracy
● Resistant to shocks and vibrations
● Response time < 100 ms
● Fully integrated electronics
● Maintenance free
● Small and good looking design
● LED switching point indicator
● Factory setting for DK (Ɛ) > 2.5