Shock-Resistant Submersible Liquid Level Sensor for Reliable Deep-Tank Measurement

Level measurement is the foundation of safe and profitable tank, well and reservoir operation. If the sensor fails, pumps run dry, tanks overflow, and inventory data becomes fiction. The QWY-310 submersible liquid level sensor is engineered for exactly those demanding installations where impact, turbulence and deep immersion destroy ordinary sensors.

Why Do You Need a Durable, Shock-Resistant Level Sensor?

In deep tanks, boreholes and open basins, the sensor probe sits at the bottom of a moving liquid column. Water hammer from pump starts, swirling turbulence from agitators, and debris carried by the flow all strike the probe continuously. A standard sensor with a thin diaphragm and fragile housing develops zero drift, blocked pressure ports, and eventual failure within months. The result is unreliable pump control, overflow risk, and costly unplanned maintenance. A shock-resistant submersible sensor keeps the measurement stable for years, so operators can trust automated level control and focus on production instead of repairs.

Working Principle: Hydrostatic Pressure Measurement

The QWY-310 measures level by sensing the hydrostatic pressure of the liquid column above its diaphragm. According to the hydrostatic equation P = ρgh, the pressure at the probe is directly proportional to the liquid height h, so a 4-20 mA output signal is generated that is linear with level. A built-in vented breathing cable connects the rear of the sensing element to atmosphere, automatically cancelling barometric pressure changes. This means the sensor reads true liquid depth, not total pressure, giving stable and repeatable level values regardless of weather or altitude.

Structural Advantages of the QWY-310

• Shock-resistant body: rugged housing absorbs impact from turbulence, water hammer and debris without zero shift.
• Vented breathing cable: polythene cable with atmospheric reference keeps readings drift-free in deep water.
• No moving parts: nothing to wear out, jam or fatigue; maintenance-free operation.
• Flexible process connection: M20×1.5 male or 1/2" NPT male suits tanks, wells and flanges.
• Standard 4-20 mA output: directly compatible with PLC, DCS and remote SCADA systems.
• Long-term stability: ±0.2% FS per year, so calibration intervals can be extended.
• Corrosion-resistant wetted parts: reliable in water, wastewater and many chemical media.
• Compact probe design: fits narrow wells and existing tank nozzles without modification.

Pain Point Analysis: 4 Challenging Working Conditions

Application Cases

Product Advantages

• Shock-resistant and impact-absorbing probe construction
• Vented breathing cable eliminates barometric error
• ±0.2% FS long-term stability per year
• 4-20 mA two-wire output, PLC/DCS/SCADA ready
• Measuring range from 0-1 bar to 0-25 bar
• M20×1.5 and 1/2" NPT process connection options
• M12 and DIN43650 electrical connection options
• No moving parts, maintenance-free operation
• Corrosion-resistant materials for harsh media
• 12-month warranty with responsive OEM/ODM support

Technical Parameters

SEO FAQ

Q1: What is a submersible liquid level sensor and how does it work?

A submersible liquid level sensor measures liquid depth by sensing the hydrostatic pressure of the liquid column above its diaphragm. The probe is lowered into the tank, well or basin and the pressure at the probe increases linearly with liquid height. The QWY-310 converts this pressure into a standard 4-20 mA signal that any PLC, DCS or display can read directly. A vented breathing cable connects the sensing element to atmosphere so that changes in barometric pressure are automatically cancelled, which means the output always represents true liquid depth rather than absolute pressure. This makes installation simple: lower the probe, connect the cable, and configure the range.

Q2: What does the shock-resistant design protect against?

The shock-resistant construction protects the sensing element and housing from mechanical impacts that occur in real installations. Water hammer from pump starts sends pressure spikes through the liquid column, agitators create turbulence that pounds the probe, and suspended debris strikes the body continuously. In ordinary sensors these impacts cause diaphragm fatigue, zero drift and premature failure. The QWY-310 absorbs these impacts without shifting its zero point, keeping readings accurate and stable. This is especially important in sewage basins, deep wells and process tanks where the sensor cannot be easily retrieved for frequent recalibration.

Q3: Why does the sensor need a vented breathing cable?

A vented breathing cable has a small internal tube open to the atmosphere at the cable end. Without this vent, the rear side of the sensing diaphragm would be sealed, and the sensor would measure the sum of liquid pressure plus atmospheric pressure. When the weather changes or the installation altitude differs, barometric pressure changes would appear as false level readings. The breathing cable equalizes the reference side with ambient air at all times, so the sensor measures only the hydrostatic pressure of the liquid. This is essential for accurate level measurement in outdoor tanks, deep wells and reservoirs where atmospheric pressure varies continuously.

Q4: What output signal does the QWY-310 provide?

The QWY-310 provides a standard two-wire 4-20 mA output, which is the most widely used analog signal in industrial automation. The 4 mA point represents zero level and 20 mA represents full scale, so the signal is directly compatible with PLC analog input cards, DCS systems, SCADA remote terminal units, panel meters and data loggers without any converter. Two-wire loop-powered operation means the sensor is powered by the same two wires that carry the signal, simplifying cabling and reducing installation cost. If you need HART communication or a digital bus output for a specific project, please contact us to discuss alternative output options.

Q5: What measuring ranges are available?

The QWY-310 is available with measuring ranges from 0-1 bar up to 0-25 bar, which corresponds to water column depths of approximately 10 to 250 meters. This wide selection covers shallow sumps, standard process tanks, deep wells, reservoirs and borehole monitoring applications. When ordering, specify the exact range you need and we will factory-calibrate the sensor to that range with a standard 4-20 mA mapping. For applications between standard ranges, custom calibration is available. Choosing the right range is important because a sensor calibrated for 25 bar will have reduced resolution when used in a 2-meter tank, so select the range closest to your actual level span.

Q6: Can the sensor be used with corrosive liquids?

Yes, the QWY-310 is designed with corrosion-resistant materials and can be used with water, wastewater and many chemical media. The polythene cable and robust housing resist moisture and chemical attack in typical industrial environments. However, the final material compatibility always depends on the specific chemical, its concentration and temperature. For highly corrosive media such as strong acids, strong alkalis or organic solvents, we recommend discussing the application with our engineers so that the wetted materials can be matched to your medium. We can provide material compatibility guidance and, where necessary, alternative wetted part options for aggressive chemical service.

Q7: How is the sensor installed in a tank or well?

Installation is straightforward. For tanks, the probe can be suspended from the top using the cable or mounted through a bottom nozzle using the M20×1.5 or 1/2" NPT process connection. For wells and boreholes, the probe is lowered to a fixed depth below the lowest expected water level and the cable is anchored at the wellhead to prevent movement. It is important that the probe never rests on sludge or debris at the bottom, as this could block the pressure port. In turbulent or debris-laden applications, a stilling well or protective tube is recommended. The cable should be secured with strain relief so that its own weight does not pull on the probe connections.

Q8: How accurate and stable is the sensor over time?

The QWY-310 offers excellent accuracy for level measurement applications and a long-term stability of ±0.2% FS per year. This means that after one year of continuous service, the reading will have drifted by no more than 0.2% of the full-scale range, which is negligible for most level control and inventory applications. The high stability is achieved through the robust sensing element and the vented reference design that eliminates barometric drift. As a result, calibration intervals can be extended and operators can trust the level readings without frequent manual checks, reducing maintenance workload and total cost of ownership.

Q9: What electrical connections are available?

The QWY-310 can be supplied with an M12 connector or a DIN43650 plug connector. The M12 connector is a compact, IP-rated circular connector widely used in industrial sensors; it provides a secure, watertight connection and allows quick replacement of the sensor without rewiring. The DIN43650 plug (Hirschmann-style) is a classic industrial standard with screw terminals inside the plug housing. Choose the option that matches the connector standard already used in your plant, or specify your preferred cable length. For permanent installations, the cable can also be directly terminated at the sensor. Our engineers can advise on the best option for your wiring scheme.

Q10: What warranty and after-sales support do you provide?

Every QWY-310 submersible liquid level sensor is covered by a 12-month warranty against manufacturing defects under normal operating conditions. Beyond the warranty, we provide responsive technical support including installation guidance, troubleshooting and calibration advice. As a manufacturer, we also offer OEM and ODM services such as custom ranges, custom cable lengths, custom labeling and packaging to match your brand. With a monthly supply capacity of 100 pieces and delivery within 5-8 working days, we can support both small pilot projects and ongoing series production. Please contact us with your application details for a quotation.

Why Choose Our Submersible Liquid Level Sensor?

The QWY-310 is built by a pressure instrumentation manufacturer with decades of process measurement experience, not a general electronics assembler. Every sensor is factory-calibrated, individually tested and delivered with the exact range, connection and cable length your project requires. You get a genuinely shock-resistant, drift-free submersible level sensor at a direct-from-factory price, backed by responsive engineering support, OEM/ODM flexibility and a 12-month warranty. When your level measurement must survive real working conditions, choose the sensor that is designed for them.