Level Control - WIKA
Level control is essential for many industrial and commercial applications, ranging from simple water tanks to complex chemical processing systems. Industrial applications often require control to maintain safe and...
Categories from WIKA (3)
Differential Pressure Control
Differential pressure liquid control products are essential components used in various applications to monitor and control the pressure difference between two points in a liquid system. These products are designed to measure the pressure drop across filters, pumps, valves, or other flow control devices. They are crucial in maintaining proper flow rates, preventing system damage, and ensuring optimal performance. Differential pressure liquid control products typically consist of a differential pressure transmitter or sensor, a flow element (such as an orifice plate, venturi tube, or flow nozzle), and associated piping and instrumentation. The transmitter or sensor detects the pressure difference and converts it into a proportional electrical signal, which can be used for monitoring, control, or alarm. These control products find applications in oil and gas, chemical processing, water and wastewater treatment, and HVAC systems. They help optimize system efficiency, improve process control, and ensure liquid systems' safe and reliable operation by providing accurate and real-time differential pressure measurements.
Related categories: Liquid Level | Level Switches | Radar | Level Sensors | Float Switch
Differential Pressure Gauges
Differential pressure gauges measure the difference between two pressure points. They show filter loading, flow through orifices, level in pressurized tanks and pressure drop across equipment.
DP Gauge Options
- Diaphragm DP gauges – low differential ranges
- Piston DP gauges – high line pressures
- DP gauges with switches – alarms and control
- Backflow test kits – backflow preventer testing
- Accessories – manifolds and mounting kits
Choosing a DP Gauge
Specify differential range, maximum line pressure, wetted materials and connection. Use 3-valve manifolds to protect gauges during startup.
Centro supplies differential pressure gauges and accessories.
Shop by type: Backflow Test Kits | Differential Pressure Gauge Accessories
Related categories: Pressure Gauges | Digital Gauges | Test Gauges | Commercial Gauges | Process Gauges
Level Sensors
Liquid level sensors detect or measure liquid in tanks and containers. They support pump control, inventory tracking and overfill protection.
Sensor Types
- Ultrasonic sensors – non-contact continuous level
- Capacitive sensors – point and continuous level
- Optical sensors – compact point detection
- Submersible pressure sensors – hydrostatic level
- Float sensors – simple, dependable
Choosing a Sensor
Consider liquid type, tank size, mounting and the output you need. Foam, vapor and buildup affect some technologies.
Centro supplies liquid level sensors.
Related categories: Liquid Level | Water Gauges | Level Switches | Differential Pressure Control | Radar
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The WIKA ILT-C01 (PN 14833190) is a 60 GHz FMCW free-beam radar level sensor with 4–20 mA current output and M12 4-pin connector. Designed for continuous, non-contact level measurement of liquids, oils, and bulk solids in industrial tanks and mobile machinery up to 212 °F (100 °C). The 4–20 mA output is ideal for long cable runs to PLCs or SCADA systems, while the M12 quick-disconnect enables fast installation and field replacement without rewiring. Rated IP67, 25 bar, ±5 mm accuracy. Vibration-resistant to 40g — engineered for hydraulic reservoirs, expansion tanks, and OEM machine integration.
Requires Quote
In Stock (975)Ships within 1 business day
The WIKA ILT-C01 (PN 14849668) delivers 60 GHz FMCW non-contact level measurement with a 0–5 V ratiometric voltage output and M12 4-pin connector. The 0–5 V signal is the preferred choice for short-distance wiring to voltage-input DAQ systems, embedded controllers, and analog I/O modules where current loops are not required. The M12 connector provides a secure, vibration-resistant mating connection suited to mobile working machines, forklifts, and industrial equipment subject to shock. Rated for media temperatures up to 212 °F (100 °C), 25 bar, IP67. Measuring range 100–5,000 mm, ±5 mm accuracy.
Requires Quote
In Stock (339)Ships within 1 business day
The WIKA ILT-C01 (PN 14849669) provides 60 GHz FMCW non-contact level measurement with a 4–20 mA current output and a 2-metre pre-wired PVC cable. The integrated cable eliminates the need for a separate mating connector, making it ideal for permanent panel wiring, junction box termination, and installations where routing flexibility is more important than quick-disconnect capability. The 4–20 mA signal ensures reliable signal transmission over long cable distances with high noise immunity. Suitable for industrial tanks, HVAC systems, wastewater applications, and mobile machinery. Rated IP67, 25 bar, up to 212 °F (100 °C), ±5 mm accuracy.
Requires Quote
In Stock (495)Ships within 1 business day
The WIKA ILT-C01 (PN 14849670) offers 60 GHz FMCW non-contact level measurement with a 0–5 V voltage output and a 2-metre pre-wired PVC cable. This combination is well-suited for OEM equipment integration where the sensor is hardwired at the factory into a voltage-input control system, removing connector cost and complexity. The flexible PVC cable accommodates tight routing around obstacles in compact machine enclosures. Ideal for coolant tanks, hydraulic reservoirs, and container-level monitoring in industrial automation. IP67, 25 bar, media temperature up to 212 °F (100 °C), measuring range 100–5,000 mm.
$638.61
In Stock (146)Ships within 1 business day
The WIKA ILT-C05 (PN 14849671) is the high-temperature variant of the ILT free-beam radar level sensor, featuring a 4–20 mA current output and M12 4-pin connector. Rated for media temperatures up to 302 °F (150 °C), it is specifically designed for hot oil reservoirs, thermal fluid systems, steam-adjacent tanks, and heated process vessels where standard sensors cannot operate. The 4–20 mA output provides noise-immune signal transmission over long cable runs to PLCs and control panels, and the M12 connector allows fast sensor swap-out during maintenance without downtime. IP67, 25 bar, 60 GHz FMCW, ±5 mm accuracy. Min. pipe diameter 18 mm.
Requires Quote
In Stock (97)Ships within 1 business day
The WIKA ILT-C05 (PN 14849672) delivers non-contact 60 GHz FMCW level measurement at media temperatures up to 302 °F (150 °C), with a 0–5 V voltage output and M12 4-pin connector. The voltage output is ideal for integration with embedded controllers, machine PLCs, and analog input cards that accept 0–5 V signals directly, avoiding the need for current-to-voltage conversion. The M12 connection is especially practical in high-temperature environments where frequent maintenance or sensor replacement is required. Suited for hot hydraulic circuits, heated industrial tanks, and high-temperature mobile machinery. IP67, 25 bar, ±5 mm accuracy, min. pipe diameter 18 mm.
Requires Quote
In Stock (99)Ships within 1 business day
The WIKA ILT-C05 (PN 14849673) is a high-temperature 60 GHz FMCW radar level sensor with 4–20 mA output and a 2-metre pre-wired PVC cable, rated for media up to 302 °F (150 °C). The factory-attached cable makes this variant ideal for permanent installation in high-temperature process environments — such as heated chemical tanks, hot-water storage vessels, thermal oil systems, and industrial dryers — where a fixed wiring layout is preferred over connectorized designs. The industry-standard 4–20 mA signal travels reliably over long distances without interference from surrounding equipment. IP67 ingress protection, 25 bar pressure rating, ±5 mm accuracy, min. pipe diameter 18 mm.
Requires Quote
Available for Purchase
Subject to factory lead times
The WIKA ILT-C05 (PN 14849674) combines high-temperature performance up to 302 °F (150 °C) with a 0–5 V voltage output and 2-metre pre-wired PVC cable — ideal for OEM manufacturers integrating a radar level sensor directly into high-temperature equipment at the production stage. The hardwired cable and voltage output eliminate connector cost and simplify assembly, making this variant well-suited for bespoke industrial machines, heated OEM enclosures, and high-temp process skids where the sensor is specified once and installed for the long term. 60 GHz FMCW, IP67, 25 bar, ±5 mm accuracy, non-contact, maintenance-free, min. pipe dia. 18 mm.
$713.34
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
Low Stock (1)Ships within 1 business day
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
In Stock (6)Ships within 1 business day
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA ILT-C01 (PN 14833190) is a 60 GHz FMCW free-beam radar level sensor with 4–20 mA current output and M12 4-pin connector. Designed for continuous, non-contact level measurement of liquids, oils, and bulk solids in industrial tanks and mobile machinery up to 212 °F (100 °C). The 4–20 mA output is ideal for long cable runs to PLCs or SCADA systems, while the M12 quick-disconnect enables fast installation and field replacement without rewiring. Rated IP67, 25 bar, ±5 mm accuracy. Vibration-resistant to 40g — engineered for hydraulic reservoirs, expansion tanks, and OEM machine integration.
Requires Quote
In Stock (975)Ships within 1 business day
The WIKA ILT-C01 (PN 14849668) delivers 60 GHz FMCW non-contact level measurement with a 0–5 V ratiometric voltage output and M12 4-pin connector. The 0–5 V signal is the preferred choice for short-distance wiring to voltage-input DAQ systems, embedded controllers, and analog I/O modules where current loops are not required. The M12 connector provides a secure, vibration-resistant mating connection suited to mobile working machines, forklifts, and industrial equipment subject to shock. Rated for media temperatures up to 212 °F (100 °C), 25 bar, IP67. Measuring range 100–5,000 mm, ±5 mm accuracy.
Requires Quote
In Stock (339)Ships within 1 business day
The WIKA ILT-C01 (PN 14849669) provides 60 GHz FMCW non-contact level measurement with a 4–20 mA current output and a 2-metre pre-wired PVC cable. The integrated cable eliminates the need for a separate mating connector, making it ideal for permanent panel wiring, junction box termination, and installations where routing flexibility is more important than quick-disconnect capability. The 4–20 mA signal ensures reliable signal transmission over long cable distances with high noise immunity. Suitable for industrial tanks, HVAC systems, wastewater applications, and mobile machinery. Rated IP67, 25 bar, up to 212 °F (100 °C), ±5 mm accuracy.
Requires Quote
In Stock (495)Ships within 1 business day
The WIKA ILT-C01 (PN 14849670) offers 60 GHz FMCW non-contact level measurement with a 0–5 V voltage output and a 2-metre pre-wired PVC cable. This combination is well-suited for OEM equipment integration where the sensor is hardwired at the factory into a voltage-input control system, removing connector cost and complexity. The flexible PVC cable accommodates tight routing around obstacles in compact machine enclosures. Ideal for coolant tanks, hydraulic reservoirs, and container-level monitoring in industrial automation. IP67, 25 bar, media temperature up to 212 °F (100 °C), measuring range 100–5,000 mm.
$638.61
In Stock (146)Ships within 1 business day
The WIKA ILT-C05 (PN 14849671) is the high-temperature variant of the ILT free-beam radar level sensor, featuring a 4–20 mA current output and M12 4-pin connector. Rated for media temperatures up to 302 °F (150 °C), it is specifically designed for hot oil reservoirs, thermal fluid systems, steam-adjacent tanks, and heated process vessels where standard sensors cannot operate. The 4–20 mA output provides noise-immune signal transmission over long cable runs to PLCs and control panels, and the M12 connector allows fast sensor swap-out during maintenance without downtime. IP67, 25 bar, 60 GHz FMCW, ±5 mm accuracy. Min. pipe diameter 18 mm.
Requires Quote
In Stock (97)Ships within 1 business day
The WIKA ILT-C05 (PN 14849672) delivers non-contact 60 GHz FMCW level measurement at media temperatures up to 302 °F (150 °C), with a 0–5 V voltage output and M12 4-pin connector. The voltage output is ideal for integration with embedded controllers, machine PLCs, and analog input cards that accept 0–5 V signals directly, avoiding the need for current-to-voltage conversion. The M12 connection is especially practical in high-temperature environments where frequent maintenance or sensor replacement is required. Suited for hot hydraulic circuits, heated industrial tanks, and high-temperature mobile machinery. IP67, 25 bar, ±5 mm accuracy, min. pipe diameter 18 mm.
Requires Quote
In Stock (99)Ships within 1 business day
The WIKA ILT-C05 (PN 14849673) is a high-temperature 60 GHz FMCW radar level sensor with 4–20 mA output and a 2-metre pre-wired PVC cable, rated for media up to 302 °F (150 °C). The factory-attached cable makes this variant ideal for permanent installation in high-temperature process environments — such as heated chemical tanks, hot-water storage vessels, thermal oil systems, and industrial dryers — where a fixed wiring layout is preferred over connectorized designs. The industry-standard 4–20 mA signal travels reliably over long distances without interference from surrounding equipment. IP67 ingress protection, 25 bar pressure rating, ±5 mm accuracy, min. pipe diameter 18 mm.
Requires Quote
Available for Purchase
Subject to factory lead times
The WIKA ILT-C05 (PN 14849674) combines high-temperature performance up to 302 °F (150 °C) with a 0–5 V voltage output and 2-metre pre-wired PVC cable — ideal for OEM manufacturers integrating a radar level sensor directly into high-temperature equipment at the production stage. The hardwired cable and voltage output eliminate connector cost and simplify assembly, making this variant well-suited for bespoke industrial machines, heated OEM enclosures, and high-temp process skids where the sensor is specified once and installed for the long term. 60 GHz FMCW, IP67, 25 bar, ±5 mm accuracy, non-contact, maintenance-free, min. pipe dia. 18 mm.
$713.34
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
Low Stock (1)Ships within 1 business day
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
In Stock (6)Ships within 1 business day
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$285.51$441.93
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$299.80$464.05
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$499.24$772.77
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA Model 700.04 piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
The WIKA piston-type differential pressure gauge measures the pressure difference between two process points, making it ideal for filter monitoring, flow measurement, and level detection in tanks and vessels. Its robust piston design provides reliable indication without electrical power, suited for clean and slightly contaminated media in HVAC, industrial process, and utilities applications.
$513.56$794.94
Available for Purchase
Subject to factory lead times
FAQS
- Monitoring and controlling liquid level in a tank requires a level sensor or transmitter paired with a controller, PLC, or alarm system. The first decision is whether you need point level detection (knowing when the level hits a specific high or low threshold — for alarms or pump control) or continuous level measurement (knowing the actual level height at all times — for inventory tracking or closed-loop control). For point level, float switches are the simplest and most cost-effective option — a buoyant float actuates a switch when the liquid reaches a set point. Vibrating fork switches are a good alternative when the liquid is viscous or foaming. For continuous measurement, ultrasonic transmitters work well in open atmospheric tanks with clean liquids, radar transmitters handle pressurized vessels, vapors, and foam, and differential pressure transmitters are the traditional choice for high-pressure or high-temperature vessels. The level signal is sent to a PLC or controller that operates inlet/outlet valves or pump starts/stops to keep the level within the desired range.
- Level measurement technologies fall into two categories: point level (detecting when the level reaches a specific threshold — high, low, or intermediate) and continuous level (measuring the actual level height across the full range). Common point level technologies include float switches (a buoyant float actuates a switch at a set level — simple, reliable, and low-cost), vibrating fork switches (a tuning fork vibrates at its natural frequency in air and dampens when immersed in liquid), and capacitance point switches. Common continuous level technologies include ultrasonic (measures distance to the liquid surface using sound waves — non-contact, works well for open tanks), radar and guided wave radar (uses microwave pulses — handles high temperatures, pressures, and vapors), differential pressure transmitters (infer level from hydrostatic pressure — the traditional workhorse for pressurized vessels), magnetostrictive float-based systems, and capacitance/admittance transmitters. The right choice depends on the media (clean liquid, slurry, foam, solids), vessel conditions (temperature, pressure, agitation), accuracy requirements, and budget.
- A float switch uses a buoyant float attached to or enclosing a mechanical or magnetic switch mechanism. As the liquid level rises, the float rises with it; when it reaches the switch actuation point, the switch changes state (opens or closes a circuit), sending a discrete signal to the control system. Float switches are the simplest and most widely used point-level devices — they are reliable, inexpensive, require no power supply for mechanical types, and work in a wide range of liquids. Common applications include high-level and low-level alarms on storage tanks, sump pump control (turning the pump on when level rises and off when it falls), coolant reservoir monitoring, and condensate tank level switching. Limitations include susceptibility to fouling in viscous or coating liquids, and they are not suitable for applications with heavy turbulence or foam. For these challenging conditions, vibrating fork or capacitance-based switches are more appropriate.
- Both ultrasonic and radar are non-contact continuous level measurement technologies, but they perform differently in various conditions. Ultrasonic level transmitters are cost-effective and work well in atmospheric tanks with clean liquids and moderate temperatures — they are the standard choice for water and wastewater tanks, chemical storage, and open vessels. However, ultrasonic performance degrades in heavy vapor, dust, foam, and extreme temperatures because sound waves are affected by the medium they travel through. Radar (non-contact and guided wave) uses electromagnetic waves that are unaffected by temperature, pressure, vapor, or dust — making radar the better choice for pressurized vessels, high-temperature processes, tanks with heavy vapor blankets, and media that produce foam or surface turbulence. Guided wave radar (a probe that contacts the media) provides excellent accuracy and reliability in narrow vessels, still wells, and applications with low dielectric liquids. Radar instruments are typically more expensive than ultrasonic, so ultrasonic remains the preferred choice where conditions allow.
- Differential pressure (DP) level measurement uses a DP transmitter to infer the liquid level in a tank based on the hydrostatic pressure exerted by the liquid column. The transmitter measures the pressure difference between the bottom of the tank (where the liquid column creates pressure proportional to its height) and the top of the tank (the reference or vapor space pressure). Since pressure increases linearly with liquid height (P = ρ × g × h), the DP reading is directly proportional to level. DP level measurement is the traditional workhorse for pressurized and vacuum vessels where non-contact technologies may not perform well, and it remains widely used in oil and gas, chemical, pharmaceutical, and power generation applications. It is well-suited for high-temperature, high-pressure vessels and can handle a wide range of media. Limitations include the need for impulse piping (or remote diaphragm seals for corrosive or viscous media), and it requires the specific gravity of the liquid to remain relatively constant for accurate measurement.