Series
LSE20Compact Vibrating Level Switch
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NOSHOK
LSE20 Series Vibrating Level Switch
The NOSHOK LSE20 Series Vibrating Level Switch uses an electronically energized piezoelectric tuning fork to detect liquid level limits in tanks, pipes, and process vessels. When the oscillating fork is immersed in liquid media, the vibration frequency shifts, triggering an instant solid-state PNP transistor output. Immune to foam, air bubbles, dielectric shifts, turbulence, and viscosities up to 10,000 cP, the LSE20 is ideal for pump dry-run protection, overflow prevention, and point level control. Available with 1/2" and 3/4" NPT threads or 3-A authorized 1-1/2" and 2" Tri-Clamp® connections for food, pharmaceutical, and beverage sanitary service (CIP/SIP compatible up to 302 °F / 150 °C).
Piezoelectric tuning fork technology: frequency change triggers rapid, bounce-free electronic switching when covered by media
Provides reliable protection from run-dry conditions for pumps, tanks, and process piping systems
Immune to dielectric variations, turbulence, foam, bubbles, suspended solids, and viscosity shifts (0.1 to 10,000 cP)
316L Stainless Steel housing and wetted parts standard (optional Hastelloy® C-276 wetted parts)
Ready for quotationShare your range, connection and case requirement.
Talk to ATHApplicationsPump run-dry protection, tank overfill prevention, liquid level alarms in chemical, food & beverage, pharmaceuticals, water treatment, and OEM machinery
Switching outputPNP / 3-wire (Transistor PNP solid-state, 10 Vdc to 30 Vdc, < 1 W)
Operating pressureFull vacuum -15 psi to 930 psi (-1 bar to 64 bar)
Medium temperatureStandard: -40 °F to 212 °F (-40 °C to 100 °C); High Temp / Sanitary: -40 °F to 302 °F (-40 °C to 150 °C)
Switchpoint accuracy±0.08" (±2 mm); Repeatability: 0.004" (0.1 mm); Hysteresis: ≤ 0.12" (3 mm)
Response timeCovered by media: 0.5 seconds; Uncovered by media: 1.0 second
Viscosity & DensityViscosity: 0.1 to 10,000 cP (mPa·s); Media density: 0.5 to 2.5 g/cm³ (0.018 to 0.09 lbs/in³)
Wetted materials316L Stainless Steel (optional Hastelloy® C-276); Sanitary finish Ra < 30 µin (ASME BPE SF3)
Process connections1/2" NPT male (8), 3/4" NPT male (18), 1-1/2" Tri-Clamp® (101), 2" Tri-Clamp® (102)
Electrical connectionsDIN EN 175301-803 Form A (8 - IP65), M12 x 1 4-pin (25 - IP66/IP68)
Part number exampleLSE20 - 1 - 8 - 25
Technical data
Selection and ordering reference
Configure process connection (NPT or Sanitary Tri-Clamp), electrical termination, and output options for the NOSHOK LSE20 Series vibrating level switch.
Switching outputPNP 3-Wire Transistor (10-30 Vdc)
Wetted material316L SS (Hastelloy® C-276 opt)
Pressure rangeFull vacuum to 930 psi (64 bar)
Temperature range-40 °F to 302 °F (-40 °C to 150 °C)
Process connections1/2", 3/4" NPT, 1-1/2", 2" Tri-Clamp®
Environmental ratingIP66 / IP68 (M12) or IP65 (DIN)
Switch Output
1PNP / 3-wire (Transistor PNP, 10 Vdc to 30 Vdc)
Process Connections
81/2" NPT male thread (3" insertion)
183/4" NPT male thread (3" insertion)
1011-1/2" Sanitary Tri-Clamp® (2-3/8" insertion, Ra < 30 µin)
1022" Sanitary Tri-Clamp® (2-3/8" insertion, Ra < 30 µin)
Electrical Connections
8DIN EN 175301-803 Form A (IP65)
25M12 x 1 (4-pin, IP66/IP68)
Part number example
LSE20 - 1 - 8 - 25
LSE20SeriesVibrating level switch
1OutputPNP 3-wire transistor
8Connection1/2" NPT male
25ElectricalM12 x 1 (4-pin)
Technical specifications
Accuracy±0.08" (±2 mm) switchpoint
OutputPNP Transistor 3-wire (10-30 Vdc, < 1 W)
Wetted parts316L SS (ASME BPE SF3 sanitary)
Pressure limits-15 psi to 930 psi (-1 bar to 64 bar)
Medium temperature-40 °F to 302 °F (-40 °C to 150 °C)
Viscosity range0.1 to 10,000 cP (mPa·s)
Operating notes
Tuning fork frequency shifts immediately upon media immersion to trigger solid-state switching.
Ideal for run-dry pump protection, vessel overflow prevention, and point level alarms.
Compatible with CIP acid/caustic wash and SIP steam sterilization up to 150 °C (302 °F).
Product Description
The NOSHOK LSE20 Series is a high-performance vibrating tuning fork level switch engineered for point level detection in all types of liquids. Operating with piezoelectric crystal excitation, the fork resonates at its natural frequency in air. When surrounded by liquid, the frequency drops, which is instantly recognized by the integrated microprocessor to toggle the PNP transistor output.
Unlike float switches or optical sensors, the LSE20 has no moving mechanical parts, eliminating sticking, jamming, and mechanical fatigue. It operates reliably in turbulent tanks, agitated mixing vessels, foaming media, and viscous fluids up to 10,000 cP.
Solid-state design with no moving mechanical parts ensures maintenance-free longevity
Unaffected by bubbles, foam, turbulence, floating debris, or changing electrical conductivity
Sanitary Tri-Clamp® versions meet ASME BPE SF3 Ra < 30 µin standards for CIP/SIP sanitary washdown
Built-in electronic diagnostics with bright LED status indicator visible through the translucent body ring
Compact insertion length (3" industrial, 2-3/8" sanitary) allows easy installation in small-bore piping
Ordering Information
SeriesLSE20 (Vibrating tuning fork level switch)
Switch output1 = PNP / 3-wire (Transistor PNP solid-state)
Process connections8 = 1/2" NPT male; 18 = 3/4" NPT male; 101 = 1-1/2" Sanitary Tri-Clamp®; 102 = 2" Sanitary Tri-Clamp®
Electrical connections8 = DIN EN 175301-803 Form A (IP65); 25 = M12 x 1 (4-pin, IP66/IP68)
Wetted material optionsStandard: 316L Stainless Steel; Optional: Hastelloy® C-276 (consult factory)
AccessoriesMating M12 cables (straight & right angle in 2m, 5m, 10m lengths), sanitary gaskets and clamps
Part Number Example
Standard exampleLSE20 - 1 - 8 - 25
SeriesLSE20 = Vibrating level switch
Switch output1 = PNP / 3-wire transistor
Process connection8 = 1/2" NPT male thread
Electrical connection25 = M12 x 1 (4-pin) connector
Product Specifications
Power requirement10 Vdc to 30 Vdc (< 1 W power consumption)
Operating pressure-15 psi to 930 psi (-1 bar to 64 bar)
Accuracy parametersSwitchpoint: ±0.08" (±2 mm); Repeatability: 0.004" (0.1 mm); Hysteresis: ≤ 0.12" (3 mm)
Response timeCovered: 0.5 s; Uncovered: 1.0 s
Housing & Wetted parts316L Stainless Steel (Ra < 30 µin on sanitary Tri-Clamp models)
Temperature limitsMedia: -40 °F to 302 °F (-40 °C to 150 °C); Ambient: -40 °F to 140 °F (-40 °C to 60 °C)
Protection circuitsReverse polarity, over-voltage, and short-circuit protection; RFI, EMI and ESD shielding
WeightApproximately 7 oz (200 g)
Operating Notes
Install the tuning fork with the tines aligned vertically in horizontal pipes to prevent sediment buildup between the fork blades.
In agitated tanks, mount away from direct inlet splash or install a protective baffle.
Sanitary Tri-Clamp® models are fully compatible with standard CIP acid/caustic wash cycles and SIP steam cycles up to 302 °F (150 °C).
LED ring shows status in real time: Green = Switch Open, Red = Switch Closed, Flashing Red = Output Fault.
Immune to media conductivity changes, allowing universal use across pure water, syrups, oils, chemicals, and slurries.
M12 x 1 connector version is sealed to IP66/IP68 for washdown environments and outdoor installations.