Ensure seamless control of liquid levels with our Level Switches. Engineered for simplicity and effectiveness, our switches offer reliable detection of high and low liquid levels to prevent overflow or dry running. With robust construction and easy installation, our Level Switches are suitable for a wide range of applications, from industrial processes to residential sump pumps. Choose our switches for peace of mind and efficient liquid level management.
Level Switch
A pump running dry, a tank overflowing, or a silo overfilling can cost you hours of downtime and thousands in damage. A level switch is the simple, reliable guard that watches your high and low levels and acts immediately – no PLC needed, no complex programming.
Here you'll discover level switches for liquids, powders, granules, and slurries – from capacitance switches that work with sticky media to tuning fork switches that ignore foam and build‑up. On this page, we help you choose the right sensing principle, output (PNP/NPN/relay), and process connection so your system stays safe and your materials never run out or spill over.
What Is a Level Switch?
A level switch is an electromechanical or electronic device that detects the presence or absence of material at a specific point in a tank, hopper, or pipe. When the material reaches the switch point, the device changes state – opening or closing a circuit, activating a relay, or sending a signal to a PLC or alarm.
Unlike a continuous level transmitter, a level switch gives a simple on/off indication (high level, low level, or pump control). It is rugged, easy to install, and extremely reliable because it has no moving parts (in most electronic designs) or very few mechanical parts.
Two common technologies dominate industrial level switching:
Capacitance level switches – measure the change in capacitance between a probe and the tank wall (or a reference electrode). When the medium covers the probe, the dielectric constant changes, triggering the switch. They work well with conductive and non‑conductive liquids, powders, and slurries, and can be coated with PTFE for aggressive chemicals.
Tuning fork level switches – a piezoelectric crystal makes the fork vibrate at its natural frequency (around 300 Hz). When the fork is immersed in material, the vibration amplitude drops significantly. The electronics detect this change and switch the output. Tuning forks are ideal for liquids, viscous fluids, and light solids because they are immune to foam, turbulence, and most coating.
Types of Level Switches We Offer
Our level switch portfolio covers the two most widely used technologies: capacitance (frequency sweep) and tuning fork. Both are available with stainless steel wetted parts and a range of outputs.
Capacitance Level Switch (HWM11)
The HWM11 uses a high‑frequency electric field to measure the capacitance between the probe and the medium. Because air and the process medium have different dielectric constants, the switch reliably detects covered vs. uncovered states. A built‑in indicator lamp shows the status (off = uncovered, on = covered). The switch is not affected by foam – it can detect liquid through foam or ignore foam on top of the liquid. It can even detect adhesive conductive slurries, pure water, metal powder, plastic powder, and ultra‑fine powders. The alarm threshold can be set on‑site using a handheld programmer, making calibration easy for different media.
Best when you need:
Detection of sticky, conductive, or low‑dielectric media (DC ≥1.5).
Operation with foam, coating, or condensation.
A compact, side‑mount or top‑mount switch.
Standard or high‑temperature version (up to 235 °C).
NPN/PNP (NO/NC) output, 12‑30 VDC.
Tuning Fork Level Switch (HYM610)
The HYM610 uses a piezoelectric crystal to vibrate the tuning fork. When the fork is immersed in material, the resonance damping causes a sharp drop in amplitude and a change in frequency/phase. The internal electronics immediately convert this into a switching signal. The switch is available with relay contact output (for AC or DC power) or DC voltage output. An LED indicator shows the fork vibrating (green) or covered (red). The housing is die‑cast aluminium (IP66), and the fork is 304 or 316 stainless steel. Process connections include threads or flanges.
Best when you need:
Reliable point level detection for liquids (density ≥0.6 g/cm³) and light solids/powders.
Immunity to foam, turbulence, and variations in dielectric constant.
Direct operation of pumps or valves using relay contacts (up to 2 A).
High‑temperature media up to 150 °C (standard) or custom higher.
Simple installation – no calibration needed for most media.
Quick comparison
| Model | Technology | Media | Output | Power | Special feature |
|---|---|---|---|---|---|
| HWM11 | Capacitance (frequency sweep) | Liquids, slurries, powders, sticky media, foam | NPN/PNP (NO/NC) | 12‑30 VDC | Handheld programmer for AL1, high‑temp option (235 °C) |
| HYM610 | Tuning fork (piezoelectric) | Liquids (≥0.6 g/cm³), powders, granules | Relay (DPDT) or DC voltage | 24 VDC or 110/220 VAC | IP66, high/low alarm mode, sensitivity adjustable |
Level Switch Applications by Industry
Water & Wastewater
Lift stations, pump pits, and storage tanks need reliable low‑level protection to prevent pumps from running dry and high‑level alarms to prevent overflows. Tuning fork switches (HYM610) are ideal for wastewater because they are not affected by foam or floating debris.
Chemical & Petrochemical
Corrosive liquids, solvents, and aggressive slurries demand chemically resistant wetted parts. The HWM11 with PEEK/PTFE coating and 316L probe can handle acids, alkalis, and many solvents. The capacitance principle works even with changing dielectric constants.
Food & Beverage
Silos for flour, sugar, or grains, and tanks for syrups or oils. Tuning fork switches (HYM610) are hygienic (Ra <0.8 μm on request) and easy to clean. Capacitance switches can be used for sticky products like honey or chocolate.
Pharmaceuticals
High‑purity water (WFI) loops, fermenters, and powder handling systems. Both switch types are available with electropolished 316L and sanitary clamps or threads.
Bulk Solids & Powders
Cement, plastic pellets, coal dust, and metal powders. Tuning fork switches are preferred because they are not affected by dust accumulation and can be installed vertically or at an angle. Capacitance switches work well for very fine powders (e.g., toner, flour).
How to Choose the Right Level Switch
Determine the medium properties
Liquid with foam, or changing dielectric constant → tuning fork (HYM610) is usually the best choice; foam does not damp the fork, but the liquid below does.
Sticky, coating, or conductive slurry → capacitance (HWM11) – it can be programmed to ignore build‑up and detect the product behind it.
Powder or fine granules → either works, but tuning fork is more common because it is self‑cleaning (vibration shakes off light powder).
Low dielectric constant (e.g., oils, plastics) → capacitance may need a reference electrode or special calibration; tuning fork is easier.
High temperature (>150 °C) → HWM11 with high‑temp option (235 °C) is suitable; for tuning fork, consult custom.
Output & power
Direct pump control or alarm relay – HYM610 with relay contact output (220 VAC or 24 VDC) is simple and does not require a PLC.
PLC/controller with DC inputs – HWM11 with NPN/PNP (24 VDC) is easy to interface.
Long cable runs or hazardous area – use a relay output switch with intrinsically safe barrier.
Process connection & installation
Threaded – G1/2, G1, NPT – standard for side mounting on tanks or pipes.
Flanged – for large tanks or high pressure.
Sanitary (tri‑clamp) – available on request.
Top mounting – for high‑level alarm (overfill prevention). Ensure the fork or probe extends below the desired alarm point.
Side mounting – for low‑level alarm (pump protection) or intermediate level.
Environmental conditions
Outdoor / dusty / washdown – IP66 (HYM610) or IP67 (HWM11 with M12 connector) are suitable.
High ambient vibration – tuning fork is insensitive to low‑frequency vibration; capacitance may need filtering.
Level Switch FAQs
What is the difference between a level switch and a level transmitter?
A level switch provides a simple on/off output (e.g., relay closed when covered). It tells you “the level is above X” or “below Y”. A level transmitter gives a continuous 4‑20 mA signal proportional to the level. Use a switch for alarming, pump control, or interlocking. Use a transmitter for inventory or continuous monitoring.
Can a tuning fork level switch detect foam?
No – tuning forks are designed to ignore foam because foam has low density and does not damp the fork sufficiently. This is actually an advantage: you can mount the fork below the foam layer to detect the true liquid level. If you need to detect the presence of foam itself, a capacitance switch (HWM11) can be set to respond to foam.
Does a capacitance level switch require calibration for every medium?
Yes, the HWM11 allows on‑site setting of the alarm threshold (AL1) using a handheld programmer. You can set “value in air” and “value in medium” for both low‑ and high‑dielectric materials. This takes only a few minutes and ensures reliable switching.
What is the minimum density for a tuning fork switch?
The HYM610 works reliably for liquids with density ≥0.6 g/cm³ (most water‑based liquids, oils, and solvents). For lighter liquids (e.g., some solvents or LPG), a capacitance switch may be more suitable.
Can I use a level switch in a high‑temperature process?
Yes. The HWM11 standard version works up to 115 °C, and the high‑temperature version up to 235 °C (custom). The HYM610 standard works up to 150 °C. For higher temperatures, please contact us for special designs.
How do I prevent false alarms due to material build‑up?
For tuning forks, the self‑cleaning vibration usually prevents build‑up. For sticky materials, the HWM11 capacitance switch can be programmed with a alarm threshold that ignores the dielectric change of coating (e.g., set AL1 to a value that only triggers when the probe is fully covered by the product, not by thin coating).
Why Choose Our Level Switches?
We design and manufacture capacitance and tuning fork level switches that work reliably in demanding industrial conditions – from corrosive chemicals to sticky food products and dusty silos.
Robust, Industrial‑Grade Construction
Wetted materials – 304/316L stainless steel, PEEK, PTFE coating for corrosive media.
Housing – die‑cast aluminium (IP66) or stainless steel (IP67).
Temperature range – standard up to 150 °C, high‑temp options up to 235 °C.
Pressure rating – up to 10 MPa (100 bar) for capacitance switch.
Easy to Install & Configure
On‑site adjustment – HWM11 can be calibrated with a handheld programmer in minutes.
No calibration needed – HYM610 tuning fork works straight out of the box for most liquids and solids; sensitivity can be adjusted with a potentiometer.
LED status indicators – show power, fork vibration, and switch state.
Flexible Outputs & Power
Relay (DPDT) – for direct pump or alarm control (220 VAC or 24 VDC).
NPN/PNP (NO/NC) – for PLC or controller inputs (12‑30 VDC).
High or low fail‑safe mode – selectable for safety.
Fast Support & Customisation
We help you choose the correct sensing technology, probe length, process connection, and output for your specific material. For OEM or project orders, we can customise probe lengths, special coatings, and high‑temperature designs. Samples are available for testing.
