Gems™ Sensors & Controls is a leading manufacturer of level switches, pressure switches, pressure transducers, flow switches, miniature solenoid valves, proximity switches and liquid level control units for use in a broad range of fluids across industries.

1. GEMS™ SENSORS &
CONTROLS
LIQUID LEVEL SENSING
TECHNOLOGIES
Website: www.GemsSensors.com Call : 1-800-378-
1600

2. VARIOUS TECHNOLOGIES…..
Each of today’s liquid level sensing technologies
excels in various roles and primarily includes the
following types:
• Float or Buoyancy • Pressure
• Conductivity • Load Cells
• Capacitance • Piezo Resonant
• Ultrasonic • Optical
Website: www.GemsSensors.com Call : 1-800-378-
1600

3. FLOAT/BUOYANCY
Pros: Non-powered, proven, direct indication
Cons: Invasive, contact fluids, moving parts
Typical Applications: Water Tanks, saline, buffer,
and reagent bottle content monitoring
CONDUCTIVITY
Pros: No moving parts, low cost
Cons: Invasive, probe erosion, liquid needs to be
conductive
Typical Applications: Boiler water, reagent
monitoring
Website: www.GemsSensors.com Call : 1-800-378-
1600

4. CAPACITANCE
Pros: No moving parts, can be non-invasive,
accurate
Cons: Continuous calibration, needs resistive liquids
Typical Applications: Reagent, waste, and wash
container levels
ULTRASONIC
Pros: No moving parts, small, accurate
Cons: Expensive, invasive
Typical Applications: Large process tanks
pharmaceutical
Website: www.GemsSensors.com Call : 1-800-378-
1600

5. PIEZO-RESONANT
Pros: Non-invasive/non-contact, accurate, repeatable,
and economical
Cons: Powered, works only with plastic containers,
wall thickness, temperature limitations
Typical Applications: Reagents, waste, diluents, wash,
saline, pure water
ExOsense Piezo-Resonant
Sensor
Website: www.GemsSensors.com Call : 1-800-378-
1600

6. ELECTRO-OPTICAL
Pros: Compact, no moving parts, high temperature
capability
Cons: Invasive, powered, and can be affected by dry
or coating media
Typical Applications: Reagents, waste, dialysate,
detergent/wash, and coolant
Website: www.GemsSensors.com Call : 1-800-378-
1600

7. ELECTRO-OPTIC OPERATING
PRINCIPLE
•Contains an infrared LED and a light receiver
•Light from the LED is directed into a prism which forms the tip of
the sensor
•With no liquid, light from the LED is reflected within the prism to
the receiver
•When liquid immerses the prism, the light is refracted out into the
liquid, leaving little or no light to reach the receiver
•Sensing this change, the receiver actuates electronic switching
within the unit to operate an external alarm or control circuit
Website: www.GemsSensors.com Call : 1-800-378-
1600

8. FOR INQUIRIES
Website:
www.GemsSensors.com
Phone: 1-860-747-3000 | Fax: 860-747-
4244
Email: info@gemssensors.com
Address: Gems Sensors & Control, One
Cowles Road, Plainville, CT 06062-1198