Demand is high for new level sensing technologies in China and India and in many markets around the world. New products, such as ultrasonic level meters and guided-wave microwave level gauges, are attractive to the water, wastewater and agriculture markets, according to a research report from Frost & Sullivan. Level sensors are also used in cases where the level measurement would represent the leak rate in larger tanks. The other applications are in aerobic septic systems, pumping stations, chemical feed, sedimentation, mixing vessels and chlorine removal.
Another area of growth is in the food-handling equipment, beverages, pharmaceutical and packaging industries where demand for level sensors that conform to 3-A standards is important. Apart from conformance to 3-A standards, level sensors that come with clean-in-place (CIP) and sterilize-in-place (SIP) capability are attractive choices for users needing the most modern cleaning and sanitizing methods.
Newer to the market are combination sensing devices, multivariable and dual sensors that not only can measure level, but also one more parameter, such as temperature.These level sensors also include a graphical LCD and a visual alarm. The alarm alerts the operator when the programmed parameters are outside the preset ranges.
Finally, according to ARC Advisory Group, “The worldwide market for radar level devices is expected to grow at a compounded annual growth rate of 5.9% over the next five years. It will is forecasted to be $421 million in 2012.”
CONTINUOUS MEASUREMENT OF SOLIDS
Siemens Energy & Automation
Sitrans LR260 two-wire, continuous-level, radar transmitter measures any solid medium, including cement powder, fly-ash, coal, gypsum, flour, grain, aggregates and plastics. It measures up to 98 ft (30 m) even in dusty environments and temperatures up to 392 °F (200 °C). The multilingual Quick Start Wizard guides users through the programming of the transmitter. It can be programmed via the intrinsically safe infrared hand-held programmer or remotely using Simatic PDM via HART or Profibus PA without opening the lid of the device. A GUI displays echo profiles and diagnostic information.
LEVEL IN TALL VESSELS
Type 8185 guided microwave level transmitter provides continuous level measurement for both liquids and solids. It uses either a cable or rod probe of 316L stainless steel. Measuring range is up to 13 ft (rod) or 105 ft (cable), making it best for tall vessels. The measuring accuracy is not influenced by process conditions involving strong steam generation, density fluctuations, changes of dielectric current or buildup of condensation on the probe or vessel wall. Output is 4-20 mA/HART. Process temperature range is -22 °F to +302 °F.
SUBMERSIBLE AND WIRELESS
waterMONITOR datalogging level transducer with an optional ETFE- jacketed cable provides corrosion resistance in liquid level monitoring applications, such as potable ground and surface water, open-channel level measurement, down-hole, well, lake, stream and watershed management. It can store up to 600,000 level- temperature- and time-stamped measurements and is designed to operate in any wireless environment, making it suited for remote installations. Accuracy is +/-0.05% FS total error band as deep as 692 ft (210 m) H2O and has a networkable RS484 interface with selectable baud rates from 1200 to 19,200.
DISPLACER LEVEL MEASUREMENT
Emerson Process Management
Types DL3 and L3 wafer-bodied liquid level displacer gauges are designed to sense the level of an interface between two liquids or the density of a liquid in a vessel using displacer technology. The DL3 produces a 4-20 mA analog output signal and is HART-compliant. The L3 produces a pneumatic output signal.
FLOW, LEVEL, TEMPERATURE
FlexSwitch FLT flow/level/temperature switch monitors flow, level or temperature and can perform flow or level sensing along with temperature measurement simultaneously. It is built to comply with process-industry requirements for point level and interface sensing in liquid, gas or foam. The switch is hydrostatically proof-pressure-tested to 3500 psig at 70 °F. Derated with temperature, the maximum operation service recommended is 2350 psig at 500 °F. The switch is suited for use in hazardous locations and is rated for NEMA Type 4X (IP66) environments.
CONTINOUS LEVEL MEASUREMENT
Ronan Measurement Div.
IntelliPoint is an on/off point-level switch that requires no calibration or adjustment of setpoints for operation. Simply install it in a tank and apply the power. It detects the presence or absence of material without adjustments. The built-in software continuously monitors the application for changes in composition, dielectric or conductivity and maintains a repeatable trip point on the probe. Since the IntelliPoint recognizes changes in material, it is suited for non-dedicated tanks that are used for a variety of products. The switch is available in two-wire and line-powered configurations.
NUCLEAR LEVEL DEVICE
Thermo Fisher Scientific
KRILPRO nuclear interface level device is designed to improve the efficiency and stability of the delayed coking process used in refineries. It uses a reduced source size as the basis of its neutron backscatter technology to provide accurate detection of light, medium and heavy foam, as well as wet and dry coke. It enables refineries to maximize coke drum output per cycle while reducing anti-foam usage for process control.
Pepperl + Fuchs
Vibracon LVL-B Series vibration limit switches are insensitive to material build-up, external vibration and flow noise, and have no mechanical moving parts for level sensing of bulk solids materials such as coarse-grained material—grain, sugar, animal feed, beans, gypsum, plastic granules and more. The stainless steel sensors have a 10-in. vibrating rod and are available with 20-in., 40-in. and 60-in. extension pipes and a plastic housing with a cover sight glass.
OPEN CHANNEL FLOW
Emerson Process Management, Mobrey
MSP900FH ultrasonic level transmitter for use in open-channel flow measurement has a pre-wired remote temperature sensor and is suited for use in water and processing sites. Measuring 10 mm diameter x 25 mm length, the sensor can be located in an appropriately shady spot between the liquid surface and the transmitter. In this way, the system ensures that the air temperature measurement used in speed-of-sound calculation is truly representative. The transmitter is 24 Vdc loop-powered, supplied in a waterproof housing sealed to IP68. It has both analog 4-20 mA communications and digital HART options built in, and can be used stand-alone or as part of a site-wide measurement, control and data acquisition system.
SELECT THE RIGHT PRODUCT
Endress + Hauser
Eclipse guided wave radar transmitters make replacement of antiquated level control easy by using the existing cage. Remove the upper head where the flange connects to the cage. Discard this along with the displacer and other internals. The cage is now ready to be retrofitted with an Eclipse transmitter. The transmitter’s configuration takes only minutes and no calibration is required. Eclipse supports the FDT/DTM standard, and a PACTware PC software package allows for additional configuration.
LEVEL MEASUREMENT OPTIONS
OPTIFLEX 1300 C TDR level indicator for the measurement of level, volume or distance of liquids, pastes or solids in storage and process vessels now includes a 2-mm cable version. Process connections are now possible on ½ in. NPT or ¾ in. NPT threaded fittings. These features make the level indicator suited to smaller vessels, such as day tanks or totes, even for interface applications.
VEGAPULS 68 non-contact radar gauge has an optional, completely sealed protective cover. The seal allows the horn antenna to be used in applications with heavy dust, buildup or even condensation and frost. A seal at the face of the horn near the protective cover, as well as at the top of the horn, near the antenna system, prevents the ingress of dust and moisture. The protective cover for the VEGAPULS 68 is rated up to 266 °F. It also has a special contact ring between the horn antenna and the PTFE cover that prevents electrostatic charge from building up on the face of the cover. Typical applications are continuous measurement of grains, cement and other dusty solids.