IP67 / IP68 StandardOEM volume supplyRFQ reply within 24 h
Key facts
SEGMENsensor manufactures liquid level sensors for point and continuous measurement: SFL float switches for high and low alarms, SLS submersible hydrostatic transmitters for wells and tanks, SEU ultrasonic sensors for non-contact measurement, and magnetostrictive level transmitters for high-resolution tank gauging. All are built in Shenzhen and supplied factory-direct.
SLS submersible transmitters cover 0.5–200 m H₂O with ±0.1% to ±0.5% FS accuracy and IP68 for continuous immersion.
SEU ultrasonic sensors measure 0.25–15 m with ±0.3% FS accuracy and no wetted parts.
SFL float switches handle liquid temperatures from -40 to +120 °C, with a +150 °C high-temperature version.
Outputs include relay, 4-20 mA, 0-10 V and RS-485 Modbus, depending on the series.
ATEX/IECEx versions are an option on SFL and SLS; qualification samples are 1–5 pcs for all series.
Last updated · SEGMENsensor Engineering Team
Watch: how our level sensors are made and tested
Submersible Level Transmitter: Installation and 4–20 mA WiringWhere to place the probe, stilling pipe and vented cable, 2-wire 4–20 mA wiring to a PLC, scaling the signal on a 0–10 m range, and what to specify before ordering.
Submersible level transmitters: how to install and wire them for a stable reading. The probe sits at the bottom and measures the pressure of the liquid above it. For water, 1 m gives about 0.1 bar. A small vent tube in the cable connects the sensor to the air, so changes in atmospheric pressure cancel out. To install, lower the probe to the bottom of the tank or well, and keep it clear of sludge. In moving or turbulent liquid, guide the probe in a stilling pipe so it hangs still. Keep the vent tube open to the air and dry. End the cable in a vented junction box. Wiring is a 2-wire loop: one cable pair carries both the 12–36 V DC supply and the 4–20 mA signal. Connect the supply positive to the transmitter, and the transmitter's return to the analog input of the PLC. On a 0–10 m range, 4 mA is empty, 12 mA is 5 m and 20 mA is full. To convert: subtract 4 mA, divide by 16 mA, multiply by the range. Specify the range (0.5–200 mWC) and the cable length: 5 m standard, or made to your installation depth. Standard accuracy is ±0.1% FS, with a 316L stainless steel probe rated IP68. For chemical media, a PTFE cable is available. On the production line, sealed stainless assemblies are pressurised with air and held under water, where any leak would show as bubbles. Housings are checked before assembly. SEGMENsensor submersible level transmitters. OEM volume supply. Quotes at segmensensor.com.
How a Submersible Level Transmitter WorksOne-minute animation of hydrostatic level measurement: pressure at the bottom of the tank, h = P ÷ (ρ·g), the vented cable that cancels atmospheric pressure, and scaling the level to 4–20 mA.
How does a submersible level transmitter measure level? The transmitter sits at the bottom of the tank. The higher the liquid, the higher the pressure on the sensor. Pressure = density × gravity × height, so height is pressure divided by density and gravity. For water, 1 m gives about 0.1 bar. A small vent tube in the cable connects the sensor to the atmosphere, so changes in air pressure cancel out. The output is 4–20 mA. On a 0–10 m range, 4 mA is empty, 12 mA is 5 m, and 20 mA is full. SEGMENsensor submersible level transmitters: 0.5–200 mWC. Try our level calculator at segmensensor.com.
Float Level Switches: From Moulding to 100% TestingReal production footage of float level switches: PP moulding, reed switch wiring, sealing, float assembly, a function check on every switch and a multi-station test rig.
Float level switches: from moulding to 100% testing. On the production line, the stems and floats are injection-moulded from white PP. Reed switch boards are soldered to the lead wires. The wired boards are fitted into the stems. An automatic dispenser then fills and seals each stem. Each float is fitted on its stem and held with a retaining clip. Every switch is then checked by hand for its switching function. On a multi-station test rig, the floats travel up and down while each switching point is checked, and panel meters show the result for every station. Float level switches · OEM volume supply. Request a quote at segmensensor.com.
Stainless Steel Sensor Housings: Sealed and Leak-TestedProduction footage of stainless steel housings and rods for level and position sensors: machined housings, threaded process connections, pneumatic pressing and an air-pressure leak test under water for every sealed assembly.
Stainless steel housings and rods for level and position sensors. On the production line, machined stainless steel housings are sorted and checked before assembly. Sensor rods are fitted with threaded process connections. Parts are joined on a pneumatic press. Every sealed assembly is then leak-tested: it is pressurised with air and held under water, where any leak would show as bubbles. Request a quote at segmensensor.com.
Made and tested in our factory
Injection moulding of float switch stems and floatsMulti-station test rig for float level switchesStainless steel sensor rods staged for assembly
Every unit is tested before shipment. Photos from our own production and test lines.
What is a Liquid Level Sensor?
A liquid level sensor detects or measures the level of a liquid inside a tank, vessel, or reservoir. SEGMENsensor manufactures five main types: magnetic float level switches for point detection, submersible hydrostatic transmitters for continuous 4-20mA measurement, ultrasonic non-contact sensors for corrosive or foam-laden liquids, capacitive level switches for conductive/non-conductive fluids, and coolant level sensors specifically designed for CDU data center liquid-cooling systems. All models are CE certified, IP67 rated, and available for OEM custom configuration.
Float switches to submersible transmitters — all OEM-configurable with custom cable, output, and housing material.
Point-Level Detection
SFL Series — Magnetic Float Level Switch
Reed-chain or microswitch float level switches for single or multi-point detection in tanks. PP, PVDF, or 316L stainless steel housing. Vertical or horizontal mount.
Switch TypeReed switch / Microswitch / SSR
Contact Rating100 VA (reed) / 15 A (microswitch)
Temperature-40°C to +120°C (HT version up to +150°C)
Top-mounted non-contact ultrasonic level sensor for corrosive liquids, foam, or open channels. IP67, 4-20mA + relay output. Blind zone from 25 cm, range up to 15 m.
Continuous level for glue, resin, heavy oil and water. Measures capacitance and resistance together so probe coating does not read as level. Local display and push-button calibration.
All models OEM-configurable. Contact us for ATEX, HART, or IO-Link variants.
Parameter
SFL Float Switch
SLS Submersible Transmitter
SEU Ultrasonic
Measurement Principle
Magnetic float + reed switch
Hydrostatic pressure
Ultrasonic transit-time
Measurement Type
Point level (ON/OFF)
Continuous (analog)
Continuous (analog)
Range
Tank depth up to 10 m (multi-float rod)
0.5 m – 200 m H₂O column
0.25 m – 15 m
Accuracy
N/A (switch)
±0.1% to ±0.5% FS
±0.3% FS
Output Signal
Relay / SSR / 4-20mA (multi-float)
4-20mA / 0-10V / RS-485 Modbus
4-20mA / 0-10V / RS-485 / Relay
Supply Voltage
AC 230V / DC 12–36V
DC 12–36V (2-wire 4-20mA)
DC 12–36V
IP Rating
IP67 / IP68
IP68 (continuous)
IP67
Temp. Range (Liquid)
-40°C to +120°C (HT: +150°C)
-20°C to +80°C
-20°C to +70°C (medium)
Housing Material
PP / PVDF / SUS 316L
SUS 316L / Titanium
ABS / SUS 316L (probe)
Process Connection
Side entry / top entry / flanged
Cable-suspended / threaded G½
G¾ / G1 / flanged
Hazardous Area
ATEX/IECEx (option)
ATEX/IECEx (option)
Safe area standard
Certifications
CE, RoHS, IP68
CE, RoHS, IP68
CE, RoHS, IP67
Samples
Samples 1–5 pcs for qualification; volume per project
1–5 pcs, 5–7 working days
1–5 pcs, 5–7 working days
Lead Time
Confirmed with the quotation
Confirmed with the quotation
Confirmed with the quotation
Technology
How Liquid Level Sensors Work
Three proven measurement principles — choose by application, media, and accuracy requirement.
01
Magnetic Float Principle
A buoyant float rides on the liquid surface. As the liquid rises or falls, a permanent magnet inside the float moves past reed switches mounted on the sensor rod, triggering an electrical output. No power required for mechanical reed switch variants — ideal for simple high/low alarms in water tanks, chemical vessels, and coolant reservoirs.
02
Hydrostatic Pressure Principle
A submersible pressure sensor at the bottom of the tank measures the hydrostatic column pressure of the liquid above it. The pressure-to-level conversion is linear: Level (m) = Pressure (Pa) ÷ (ρ × g). A 4-20mA signal proportional to tank level is transmitted to PLC or SCADA systems. Accuracy to ±0.1% FS, unaffected by foam or vapor.
03
Ultrasonic Non-Contact Principle
An ultrasonic transducer emits a short acoustic pulse toward the liquid surface. The time-of-flight for the echo to return is measured and converted to a distance (level) reading. Since the sensor is mounted above the liquid with no contact, it works perfectly for corrosive acids, alkalis, slurries, and foam — including dielectric coolants in CDU systems.
H2-B — Tank Applications
Water Tank Level Sensor & Industrial Tank OEM Supply
From domestic water tanks to 50,000-litre industrial process vessels — SEGMENsensor supplies custom water tank level sensors and submersible level transmitters for OEM equipment builders worldwide.
Water Tank Level Sensor OEM
SEGMENsensor's float level switches and ultrasonic non-contact sensors are widely used as water tank level sensors in building water supply systems, cooling tower make-up tanks, rainwater harvesting tanks, and fire suppression reservoirs.
✓Vertical and horizontal float switches for single or multi-level detection
✓PP, 316L SS, PVDF wetted materials — suitable for clean water to mild chemicals
✓AC 230V or DC 12-24V supply, relay output for direct pump control
Submersible Level Transmitter for Industrial Tanks
For continuous level measurement in industrial process tanks, our submersible level transmitter (SLS series) converts hydrostatic pressure to a 4-20mA signal linearly proportional to liquid depth. Suitable for 0.5 m to 200 m, in water, acids, alkalis, fuels, and slurries.
Pressure Range
0.1 bar – 100 bar
Output
4-20mA / RS-485
Accuracy
±0.1% to ±0.5% FS
Protection
IP68 continuous
Applications
Liquid Level Sensors for 8 Industry Segments
From oil & gas storage to data center liquid cooling — we specify the right sensor for your media and environment.
🛢️
Oil & Gas Storage
Float switches and submersible transmitters for crude oil, diesel, and condensate tanks, with ATEX/IECEx versions as an option on selected models. Stainless or titanium wetted parts.
💧
Water & Wastewater
IP68 submersible level transmitters for reservoirs, sewage lift stations, and flood monitoring wells. Cable lengths from 5 m to 100 m.
🧪
Chemical Plants
PVDF or PP float switches for HCl, H₂SO₄, and NaOH tanks. Non-contact ultrasonic sensors for fuming acids where metal contact is impossible.
🍺
Food & Beverage
316L SS float switches and submersible transmitters with food-grade silicone seals for CIP tanks, fermentation vessels, and sirup storage.
💻
Data Center CDU Cooling
Coolant level sensors for CDU (Coolant Distribution Unit) reservoir monitoring in AI server liquid cooling. Non-contact, dielectric-fluid compatible. See CDU section below.
🏗️
HVAC & Building Services
Float level switches for cooling tower make-up water, chilled water tanks, and condensate pits. AC 230V relay output for direct integration with building management systems.
⚙️
Machine Tools & Hydraulics
Compact float switches for CNC machine coolant sumps, hydraulic oil tanks, and lubrication reservoirs. Side-entry or top-entry installation, custom cable gland.
🚢
Marine & Offshore
Stainless steel float switches and submersible transmitters for bilge monitoring, ballast tanks, and fuel tanks on vessels. IEC 60092 marine-grade wiring available.
CDU / Data Center Liquid Cooling
Coolant Level Sensor for CDU — Data Center Liquid Cooling Systems
As AI server racks exceed 100 kW per rack, direct liquid cooling via CDU (Coolant Distribution Unit) has become the standard. SEGMENsensor offers non-contact coolant level sensors designed for CDU reservoir monitoring — a globally underserved application with zero dedicated Chinese OEM sensor pages currently online.
Non-contact ultrasonic technology — no metal parts touching dielectric coolant fluid (PAG, PGW, deionized water)
Compatible with CDU reservoir materials: HDPE, polycarbonate, acrylic-window tanks
Low-level and high-level relay alarm output for automatic CDU pump protection
4-20mA continuous level output for integration with rack management controllers (RMC)
Operating temperature: -10°C to +60°C (coolant side), matching CDU environment
Internal link: also see our CDU coolant flow meter for complete CDU liquid-loop monitoring
Media CompatibilityDielectric coolant, DI water, PAG, PGW
MountingTop-mount, G¾ thread or custom bracket
IP RatingIP67
Operating Temp.-10°C to +60°C
SupplyDC 12–24V
MOQConfirmed with the quotation
Samples1–5 pcs, 5–7 working days
Lead TimeConfirmed with the quotation
CertificationsCE, RoHS
Custom bracket, cable, and connector available for OEM rack integration. NDA on request.
OEM Manufacturing
Liquid Level Sensor OEM Manufacturer — Factory Direct Since 2019
SEGMENsensor is a direct factory — not a trading company. Our Shenzhen facility has manufactured liquid level sensors since 2019, with dedicated R&D for float switches, hydrostatic transmitters, and ultrasonic sensors. We supply OEM equipment builders across oil & gas, water treatment, semiconductor, HVAC, and data center liquid cooling markets in 30+ countries.
Custom Material & Output
PP / PVDF / 316L SS / Hastelloy wetted parts. Output: 4-20mA, 0-10V, RS-485 Modbus, HART (2-wire 4–20 mA + HART on magnetostrictive models), IO-Link on request.
Private Label & OEM Packaging
Custom logo on housing, custom color, custom label insert. Private-label datasheet and box are quoted by quantity.
CE / RoHS / ATEX Documentation
Full CE Declaration of Conformity and RoHS certificate; ATEX/IECEx versions as an option on selected models for hazardous area OEM projects.
Fast Lead Time
Production lead time for standard configurations is confirmed with the quotation; samples of 1–5 pcs in 5–7 days. Custom housing or output options: lead time confirmed at order. Expedited available for volume orders.
Why SEGMENsensor
Replacing an Installed Sensor: What to Send Us
Production in our Shenzhen factory, OEM volume supply, samples 1–5 pcs in 5–7 working days, production lead time confirmed with the quotation, reply within 24 hours on working days.
Replacing an installed sensor? Send us a photo of the nameplate or the key specifications (range, output, supply voltage, mounting dimensions, connector, medium and temperature). We will propose the matching SEGMENsensor model, and you can verify 1–5 samples first (5–7 working days). Final specifications are confirmed in the datasheet and order confirmation.
ISO 9001:2015
Quality management certified
CE Certified
EU Declaration of Conformity
ATEX/IECEx option
Hazardous area Zone 1/21
RoHS Compliant
No restricted substances
Since 2019
Core team: 20+ years of experience
30+ Countries
200+ active OEM clients
OEM Projects
Liquid Level Sensor Manufacturer for OEM Projects
SEGMENsensor builds customized liquid level sensors for equipment makers, system integrators and volume distributors: you send the tank, liquid and signal requirements, we return a drawing and datasheet, ship 1–5 qualification samples in 5–7 days (7–14 days when customized), and plan production around your annual volume, with lead time confirmed with the quotation. Every inquiry gets an engineering reply within 24 hours on working days.
How does an OEM level sensor project run?
An OEM project runs in six steps, from a requirement review to series production; the only fixed timings are the ones below.
Step
What happens
Typical timing
1. Requirement review
You send liquid, temperature, range, output, supply, process connection, cable length and estimated annual volume.
Reply within 24 h (working days)
2. Engineering proposal
We select the series (SFL, SLS, SEU or magnetostrictive) and confirm materials, output and connection on a drawing and datasheet.
Sent with the quotation
3. Qualification samples
1–5 pcs built to the agreed drawing for testing in your equipment.
5–7 days standard · 7–14 days customized
4. Customer validation
You check fit, signal and sealing; we adjust the drawing if needed.
Set by your test plan
5. Series production
Production planned around your annual volume, with function testing on every sensor.
Confirmed with the quotation
6. Shipment and support
FOB China, 100% T/T in advance, 12-month warranty.
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Which series fits which OEM application?
Choose a float switch for alarms, a submersible or ultrasonic transmitter for continuous level, and a magnetostrictive transmitter when the tank needs high-resolution gauging.
Fuel, chemical and process tanks that need high-resolution gauging
All values are taken from the series data on this page and the official datasheets; final ranges and outputs are confirmed per model at order. For a step-by-step comparison, see our guide on how to choose a liquid level sensor.
Download the one-page datasheet (PDF)
Ranges, outputs, materials and wiring for the SFL, SLS and SEU series in one page.
Stainless steel float level switches, laser welding and visual inspection in our Shenzhen factory.
Start an OEM level sensor project
Qualification samples (1–5 pcs) ship in 5–7 days for project validation, and production is planned around your annual volume. Read more about our OEM and private-label programme.
Questions from OEM buyers about liquid level sensors, selection, and custom OEM orders.
What types of liquid level sensors does SEGMENsensor manufacture?
SEGMENsensor manufactures six types: magnetic float level switches (reed chain or microswitch), submersible hydrostatic pressure transmitters (4-20mA), ultrasonic non-contact level sensors, capacitive point-level switches, optical level switches for clear/opaque liquids, and coolant level sensors for CDU data center liquid cooling systems. All types are available in custom configurations.
What is a coolant level sensor for CDU (Coolant Distribution Unit)?
A CDU coolant level sensor monitors the coolant reservoir level in liquid-cooled data center rack systems. SEGMENsensor's coolant level sensors use non-contact ultrasonic or optical technology to detect low-coolant conditions without metal parts touching the dielectric fluid, ensuring safe operation of CDU systems for AI servers and high-density computing racks. Output: 4-20mA + relay alarm.
How do qualification samples and OEM volume orders work for liquid level sensors?
Qualification samples of 1–5 pcs ship in 5–7 days for evaluation, and production is planned around your annual volume. Custom cable lengths, connector types, housing materials (PP, PVDF, 316L SS, Hastelloy), and private-label packaging are quoted by quantity, OEM volume supply.
Can liquid level sensors be used in hazardous ATEX/IECEx zones?
Yes. ATEX/IECEx explosion-protected versions are available as an option on selected models for use in oil tank farms, chemical reactors and fuel storage. The Ex marking is as stated on the certificate of the specified model, which is provided with the quotation.
What is the accuracy of submersible hydrostatic level transmitters?
SEGMENsensor submersible level transmitters achieve ±0.1% FS to ±0.5% FS accuracy depending on the model and pressure range (0.1 bar to 100 bar). The 4-20mA output is temperature-compensated over -20°C to +80°C. Long-term stability is ≤±0.1% FS per year.
How do I choose between float, ultrasonic, and submersible level sensors?
Choose float switches for simple high/low point detection (low cost, no power required for mechanical type). Choose ultrasonic non-contact sensors when the liquid is corrosive, has foam, or must not be touched. Choose submersible hydrostatic transmitters for continuous level measurement in deep tanks (0.5 m to 200 m depth), slurries, or wastewater where non-contact methods are impractical.
What output signals are available for continuous level transmitters?
Standard output options include 4-20mA (2-wire), 0-10V (3-wire), 4-20mA + RS-485 Modbus RTU, HART (2-wire 4–20 mA + HART on magnetostrictive models), and IO-Link. Relay output is available for float and optical switch types. Custom outputs for OEM integration are supported.
What non-contact level sensor works for a coolant reservoir?
For coolant reservoirs — especially in CDU liquid-cooling systems and CNC machine sumps — SEGMENsensor recommends our SEU ultrasonic non-contact level sensor or optical point-level switch. Both avoid metal contact with the dielectric coolant fluid (PAG, PGW, deionized water), preventing contamination. The ultrasonic sensor provides continuous 4-20mA level output + relay alarm; the optical switch gives a clean dry-contact ON/OFF signal for low-coolant shutdown. Both are IP67 rated and CE certified.
Is there an IP67 level sensor available from a China factory for OEM supply?
Yes. All SEGMENsensor liquid level sensors are IP67 or IP68 rated as standard — not as an option. Our Shenzhen factory (Registration No. 91440300MAEUXXQU04) manufactures and ships IP67 level sensors from OEM volume supply with CE and RoHS documentation included. Sample orders of 1–5 pcs ship in 5–7 days. Full IP68 submersible transmitters (continuous immersion) are also available. RFQ response within 24 hours.
What is the lead time for custom OEM liquid level sensor orders?
Production lead time for standard configurations is confirmed with the quotation; samples of 1–5 pcs in 5–7 days. Custom cable, connector, or housing material options: lead time confirmed at order. Full OEM private-label (custom housing mold, PCB, label) is quoted on request, with first-run lead time confirmed at order.
Is SEGMENsensor a liquid level sensor manufacturer or a trading company?
SEGMENsensor is a manufacturer. SEGMEN (Shenzhen) Industrial Development Co., Ltd. was founded in Shenzhen, China in 2019 and its engineering team has 20+ years of sensor experience. Float switches, submersible transmitters and level probes are built and tested in our ISO 9001:2015 factory, which supplies 200+ OEM customers in 30+ countries.
What can be customized on an OEM liquid level sensor?
Wetted material (PP, PVDF or 316L stainless steel), output (relay, 4-20 mA, 0-10 V or RS-485 Modbus, depending on the series), switch points and number of floats, cable length and connector, process connection, and private-label logo, label and packaging. Each change is confirmed on a drawing before samples are built.
How do qualification samples work for an OEM level sensor project?
We build 1–5 qualification samples so you can test fit, signal and sealing in your own equipment. Standard configurations ship in 5–7 days and customized samples in 7–14 days. Production is then planned around your annual volume, with lead time confirmed with the quotation.
What information should I send for an OEM liquid level sensor quotation?
Send the liquid and its temperature, the tank height or measuring range, point or continuous measurement, the output and supply voltage, the process connection and cable length, any hazardous-area requirement, and your estimated annual volume. Our engineers reply within 24 hours on working days.
Which factors affect the quote for a custom liquid level sensor?
The quote depends on the measuring range, output type, wetted and housing materials, certification options such as ATEX/IECEx, and order quantity. Quotes are FOB China with 100% T/T payment in advance, and every sensor carries a 12-month warranty.
Which certifications can OEM liquid level sensors carry?
Our factory is ISO 9001:2015 certified. Level sensors carry CE, RoHS 3 (2011/65/EU as amended by (EU) 2015/863) and UKCA, with ATEX/IECEx explosion-protected versions available as an option on selected models. Local approvals required by a specific project can be arranged on request; scope and timing are confirmed at quotation.
