Providing medical design engineers with a cost-effective alternative to ultrasonic sensors, TT electronics OPTEK Technology’s OCB350 fluid sensor features automatic calibration circuitry and is available with multiple output states including “fluid present,” “no fluid present,” and “no tube present.” The sensor is ideal for medical applications including monitoring fluid or air presence in tubing for infusion and transfusion pumps where fluids of different optical densities are used.
Designers can initiate the calibration procedure at any time by grounding the J1-pin-4, which allows the device to be remotely calibrated and then mounted in the equipment. When the system calibrates the sensor, it raises the current through the LED from 0mA to 14mA, until the phototransistor reaches the preset point.
The OCB350 Series sensor consists of an infrared LED and phototransistor packaged in an opaque plastic housing that enhances ambient light rejection. The housing features an opening designed to accommodate clear tubing with outer diameters of 0.0625” (1.6mm), 0.125” (3.2mm) or 0.1875” (4.8mm). The presence of clear liquid causes the phototransistor to sink the maximum current, while the presence of dark liquid causes it to sink the minimum current. As bubbles pass through the tube, the signal will vary between the “liquid present” and “no liquid” states. If no tube is present, the phototransistor sinks current between the dark fluid and clear fluid states.
The infrared LED features a forward DC current of 50mA with a peak current of 1.0A. Reverse DC voltage is 2.0V and power dissipation is 100mW. The output phototransistor features a maximum collector-emitter voltage of 24V or 30V, with collector DC current of 50mA and power dissipation to 100mW. Operating temperature range is from -40ºC to +85ºC.
Typical pricing for the OCB350 Series fluid sensor is $13.15 each in quantities of 1k pieces. Lead time, if stock is not available, is from 6 to 8 weeks.
Ifm’s compact PQ Series pressure sensors are designed for pneumatic applications typically found in robotics and material handling applications. The sensors precisely measure the full range of pressure and vacuum typical in these applications.
The cube-shaped pneumatic pressure sensor easily retrofits traditional pressure switches at a fraction of the price. Measuring only 32mm x 30mm x 42mm, the compact sensor can be installed in areas with limited mounting space.
Application parameters are established using two pushbuttons. The bright, four-digit display indicates system pressure and can be clearly seen from long distances. The sensor features two programmable switching outputs or one switching and one diagnostic output. In addition, the values can be programmed to change color depending on the switching output status (e.g., red if output 1 is switched; green if output 1 is not switched).
The technology is based on a piezo-resistive measuring element. The silicon measuring cell is insensitive to liquids (e.g. condensed water) and deposits that might occur in the system. The cell changes resistance when pressure is applied. The stress induced in the cell is transformed into an electric signal that is proportional to the pressure. The silicon measuring cell guarantees a high overload resistance as well as an accuracy of ± 0.5%.
For mounting purposes, the PQ pressure sensor can be fixed to flat surfaces and profiles using the sensor’s two M4 drill holes located in the front of the sensor. The PQ can be mounted to a DIN rail or connected to plates or manifolds using ifm’s robust DIN rail bracket. The sensor can be connected to air lines through the G-1/8 port using a 6mm or 8mm tubing adapter or a 1/8″ NPT adapter.
Two models are available. PQ7809 has a measuring range of -14.5 to 14.5 psi and the PQ7834 has a measuring range of -14.5 to 145 psi. Electrical connection is made through an M8 Pico DC connector.
A precision off-the-shelf liquid level sensor, developed for motorsport, military and industrial applications the ‘R-Series’ is now available from Gill Sensors. The sensor has no moving parts, utilising advanced capacitive technology to accurately monitor the liquid level.
Compatible with fuel, oil, water and other specialist liquids, the R-Series liquid level sensor features an SAE 5-bolt flange mount as standard and is manufactured to the end users’ exact length requirement, avoiding the need for any mechanical adjustment by the user. With fully integrated electronics producing a configurable 0-5V analogue output, the R-Series is seen as an ideal ‘drop-in’ solution for most liquid level applications.
In addition to the standard R-Series sensor, Gill Sensors has also introduced an ‘Rxl’ variant for applications where a very long sensor is required. This variant of the R-Series utilises the same SAE 5-bolt mounting pattern but introduces additional mechanical strengthening features to support the longer probe. This sensor targets industrial applications that require precision liquid level measurement of storage tanks up to 3m in depth, says the company.
MTC ElectroCeramics introduced its piezoelectric ceramic components and ultrasonic sensors for flow measurement of utilities, including gas, heat and water. Ultrasonic flow measurement devices can be a key component of “smart meters” designed to display hour-by-hour real time information about energy usage and pricing, facilitating residential and commercial energy conservation efforts.
Smart meters are being promoted by a $3.4 billion Smart Grid Investment Grant under the American Recovery and Reinvestment Act. It will be matched by industry, for a total investment worth more than $8 billion. More than 40 million smart meters are expected to be deployed in American homes as part of this initiative.
MTC ElectroCeramics’ piezoceramic components for measuring flow, distance and level have excellent acoustic sensitivity and mechanical strengths to withstand high pressures. Their tightly controlled resonant frequencies are key to achieving consistently good sensitivity levels. MTC ElectroCeramics offers a range of electrode materials and geometries to help customers with efficient high volume manufacturing.
MTC ElectroCeramics also uses its piezoceramic materials to design and manufacture ultrasonic sensors for metering both gas and liquid flow measurement, taking into consideration customer-specific requirements for sensor housing that operates reliably under high pressure and a wide range of temperatures. The sensors are supplied in custom designed housings complete with acoustic matching layers that enhance sensitivity and also provide the required protection from the environment. MTC ElectroCeramics’ in-house sensor test facilities ensure the best possible design solutions for specific customer needs.
Ultrasonic flowmeters are a solid state technology with no moving parts, making them more reliable than conventional mechanical meters. They suffer no pressure loss, offer nearly maintenance-free operation and are more accurate than many competing systems. In addition, they are more adaptable to the type of useful electronic display of energy use envisioned by champions of smart meters.
MTC ElectroCeramics has been supplying piezoelectric ceramic components and ultrasonic sensors to major utilities conducting ultrasonic measurement of hot and cold water, heat and natural gas flows for nearly twenty years. The use of ultrasonics for metering has been widely adopted, with more than 3 million meters installed annually in the European market.
Silicon Laboratories created an ac current sensor family that replaces traditional current transformers. Silicon Labs’ new Si85xx ac current sensors provide up to 5 kVrms of electrical isolation to ensure safety compliance for a variety of critical power delivery systems such as ac-dc switching power supplies, isolated dc-dc supplies, motor control applications and electronic lighting ballasts.
The Si85xx ac current sensors provide a more reliable, cost-effective alternative to antiquated transformers for today’s modern power delivery systems. Traditional transformers are large, bulky magnetic components that contribute significant supply losses and have parasitics that complicate system design. The highly integrated ISOpro ac current sensors feature a sophisticated architecture that minimizes the need for costly discrete components for filtering and reset circuitry. An available small-footprint QFN package eases printed circuit board (PCB) space constraints with a small 4×4x1 mm profile.
With a measurement accuracy of better than 5 percent, the Si85xx ac current sensors are available in 5 A, 10 A and 20 A versions. They provide a large output signal level of 2.0 V at full-scale output range, eliminating the need for an external amplifier. A “ping-pong” output mode enables one sensor to replace two current transformers and associated components in full-bridge applications, reducing board footprint by more than 50 percent and BOM cost by more than $0.30 (USD).
Offering the industry’s lowest parasitic losses, the Si85xx current sensors enable designers to maximize system efficiency and meet aggressive power budgets for green energy standards. The devices’ low resistance (<1.3 milliohms) and small parasitic inductance (<2 nH) result in more efficient power supplies that are easier and quicker to design.
Flow Technology, Inc. released the FT-BD turbine flow meter system. An accurate solution for measuring bi-directional flow in a wide range of liquid applications, this advanced system can also compensate for viscosity changes due to variations in ambient fluid operating temperature, which affect the accuracy of flow measurement data.
In various industrial and test & measurement processes, bi-directional flow presents difficult challenges for flow metering equipment. For example, utility pumping and circulating plants pump dielectric fluid into underground electrical cables in order to dissipate heat generated by high-voltage power lines. This application involves monitoring upstream and downstream flow rates. It also requires a precise method of viscosity compensation as the dielectric temperature changes.
Employing Flow Technology’s FT Series turbine flowmeter paired with the LinearLink(TM) Temperature Compensated Interface (TCI), the FT-BD system provides bi-directional flow measurements in a host of hydraulic, pneumatic and pumping applications. The FT Series meter is an ideal choice when high accuracy, compact size and fast response are critical. The LinearLink TCI is a sophisticated electronics platform for flow meter linearization, viscosity correction and density compensation.
With the FT-BD system, an FT Series turbine flow meter with a bi-directional Universal Viscosity Curve (UVC) calibration employs dual RF/RTD pickoffs for determining flow direction and sensing temperature. The LinearLink TCI’s innovative, temperature-compensated linearization technique reduces viscosity effects on K-factors by calculating fluid viscosity through real-time temperature measurements and proper calibration methods.
As an alternative, the FT-BD system can be employed with Flow Technology’s SL9100 Series Flow Computer. This powerful unit can be configured to display volumetric or mass units of measure with UVC and Strouhal-Roshko temperature compensation for variations in viscosity and density due to temperature. The SL9100 can output a 4-20 mA flow measurement signal to the user’s data acquisition system and display digital read-outs via a panel-mount display.
A new family of turbine flow sensors now available from Clark Solutions features innovative infrared technology to provide high-resolution flow measurement. Clark Solutions’ new PFA Turbine Flow Sensors are designed for monitoring and controlling corrosive or aggressive fluids, including fuels. PFA Flow Sensors are designed for full-scale flow ranges of 2.0 l/min, 20 l/min & 40 l/min with an accuracy of 1% of reading and a repeatability of better than 0.15%.
PFA Turbine Flow Sensors feature an ultra-lightweight rotor that generates a high resolution IR reflected digital output signal. These innovative turbine flow sensors work by having clear, opaque, or neutral liquids pass through a static worm, creating spin. The spinning fluid drives a PFA rotor into a frictionless rotation. Reflectors mounted on the rotor blades reflect IR signals to a high-resolution infrared sensor that determines the rate of flow by counting the passing reflections. The ultra low mass of the PFA rotor with ruby bearing provides very quick response to changes in the rate of flow.
In addition, the PFA can be supplied with an internal preset flow switch set via software interface, and an internal programmable batch function for dispensing and dosing applications. An external solid-state switch module, model 6300, is provided when these options are ordered.
Available for use with PFA Turbine Flow Sensors are the Model 6100 Digital to 4-20 mA Converter and the Model S601 Solid Batch and Flow Controller. Other PFA Flow Sensor models available from Clark Solutions include a stainless steel model and a disposable turbine configuration.
It was not so long ago that gas detection was biological, and canaries were the state-of-the art gas detectors. Until well into the 20th century the little birds were used to detect build-ups of deadly carbon monoxide in mines and thus saved the lives of thousands of miners.
The canaries were retired when electro-chemical sensors were developed to monitor chemical processes and measure variables, such as resistance, to detect the build up of gases. Despite the refining of the technology over a period of many years, this way of sensing gas emissions is unsatisfactory in several ways – not least the time it takes.
What was needed was a new type of sensor, based on new technologies, which could very quickly detect and identify any special or unusual gas build up in the ordinary ambient air and either sound the alarm or institute corrective measures.
A cross-disciplinary EU-funded project,NEMIS, was set up to study the problem and develop a working model of a new type of optical sensor based on recent advances in laser technology and photonics.
New type of laser
Specifically, the researchers worked to develop a system based on a new type of laser with a range of characteristics suited to detecting gases, other than those naturally occurring in air, at room temperature.
The vertical-cavity, surface-emitting semiconductor laser diodes (VCSELs) which were used to drive the NEMIS photonic sensing system for trace gas analysis allow for the construction of robust, long-lasting and low-cost sensors.
The advantages of using VCSELs rather than conventional lasers, apart from cost-efficiency, are that you can tune the wavelength more broadly. Usually a laser can only be tuned over less than a nanometre by changing the electrical current, but a VCSEL has the ability to tune over more than five nanometres.
Because the sensor is looking for anomalies in wavelengths to detect gas – in the case of the pilot study with the gas being carbon monoxide (CO) – laser ‘tunability’ allows for both greater flexibility and the ability to create a self-contained, sealed sensor.
Each gas has a unique “absorption line” which allows the laser to detect its presence, so if the laser can be tuned up and down it means a series of lines representing different gases can be detected by a single sensor.
Self-calibrating sensors
It also means that self-calibrating sensors, which continuously check against a sample of gas at a pre-set or known wavelength, before going to a different absorption line to take measurements for CO and other gases, become practical.
As the sensors are self-calibrating there is no need for human interaction and they can be sealed in tough containers which not only have a life of many years but can also be put into hostile environments in industrial installations without suffering corrosion.
Perhaps the biggest challenge for NEMIS was the wavelength. No laser was able to do what they wanted done at the wavelength range they had to work at – 2 to 3.5 µm – had been developed. So one of the main achievements of the project has been to develop lasers that are suitable for optical gas sensing.
Once the researchers had done their bit, the project’s industrial partners developed a demonstrator which initially was able to detect CO NH3 (ammonia). Sensors for other gases including carbon dioxide (CO2) and hydrogen sulphide (H2S) are under development.
Being able to accurately measure the presence of gases is crucial to the success of any process. The latest monitoring technologies are particularly focused on hydrogen, oxygen, carbon monoxide and hydrogen cyanide.The presence of other gases is an important requirement in many process industries for both process optimisation and for safety. These measurements are difficult or costly to perform, however. Now instrumentation specialist Quantitech is launching a new technology from the USA that resolves the issues concerning hydrogen.
Commenting on the market for hydrogen sensing, Quantitech sales director Dominic Duggan says: “Hydrogen monitoring does not take place in many applications because of the problems or costs associated with the available technologies, for example lack of specificity. However, the new sensors from H2scan resolve these issues offering significant advantages in process control and safety management.”
US company H2scan has developed inline, solid-state palladium-nickel based sensors that are highly selective to hydrogen, do not require oxygen to operate, and can detect hydrogen in concentrations from a few ppm to 100%.
Hydrogen has the potential to be an important source of clean fuel in our energy-driven economy. The use of hydrogen is widespread in both traditional applications, such as petroleum refineries, and growing rapidly in newer sectors such as fuel cells and power generation.
Based on recent market reports, global hydrogen consumption has grown from 21 million metric tons (MMT) in 2005 to more than 32 MMT 2007. Global hydrogen usage is expected to surpass 50 MMT by 2012 and is expected to exceed 79 MMT by 2016.
Currently, over 90 % of all hydrogen produced is used in the petroleum refining industry, where continuous monitoring of hydrogen is highly desired to improve both the quality and yield of hydrocarbon-based fuels. Because of hydrogen’s combustible and explosive properties, accurate leak detection is also important for safe hydrogen transport, storage, and use.
In certain industrial applications – such as hydrogenating cooking oil and hydro-treating petroleum crude into heating oil, gasoline, and diesel and jet fuels – it is critical to quantify the absolute concentration (partial pressure) of hydrogen in process operations to ensure process safety and operational efficiency. A typical refinery application for an inline hydrogen sensor is to measure the total hydrogen content in a mixed gas matrix (a mixture of hydrocarbons, carbon dioxide, hydrogen and other gases) as a function of time. The H2scan inline process hydrogen sensor allows direct point-of-use analysis of hydrogen concentration from 50 % to 100 %v/v.
Hydrogen producers are also interested in accurate sensing as a key part of hydrogen management. For instance, within the pharmaceutical industry, multiphase hydrogenation reactions involving solid catalysts play a critical role. Accurate hydrogen monitoring is also needed in hydrotreating and in hydrogenation processes in hydrogen production facilities.
Hydrogen sensors can now be applied to current and future gas- or liquid-filled pipelines, offering safety improvements with a hydrogen-specific sensor that can be wrapped around pipeline joints and valves to detect the first level of leakage, or additional sensors can be employed to quantify the hydrogen content of natural gas within the pipeline.
The applications for hydrogen-specific sensors have increased markedly as a result of the new technology and because accurate hydrogen monitoring is a key component of several emerging areas of the hydrogen-driven energy economy.
Complete gas analysis
Chematur Engineering of Sweden has selected Servomex and channel partner OmniProcess to supply a complete gas analysis monitoring system to a new toluene di-isocyanate (TDI) plant currently under construction in Dahej, India. The 50000t/y plant is being built on behalf of Indian chemical manufacturer GNFC.
The new system will help control the process and monitor the quality of output in the manufacturer of TDI, a key isocyanate used in the manufacture of polyurethane and used for a variety of applications including flexible foams used in furnishings and the motor industry.
Servomex will supply a range of its world-leading gas analysers to fulfil the complex requirements of TDI monitoring, including 15 SERVOTOUGH SpectraExact (2500) process gas analysers, two SERVOPRO 4210 gas purity analysers, one SERVOTOUGH OxyExact (2200) paramagnetic oxygen analyser and three k1550 katharometer-based analysers.
Designed, manufactured and tested in configurations specific to the required measurement and background stream, the SERVOTOUGH SpectraExact is a photometric process analyser that offers single or dual component gas analysis to suit virtually any process, combustion or emissions gas analysis application, making it ideal for several TDI measurement processes including monitoring the off-gases from mixing chlorine with carbon monoxide to make phosgene and monitoring for both carbon monoxide and chlorine in phosgene.
Control of residual oxygen concentration in pure carbon monoxide in the range 0-0.5 % will be made by the SERVOTOUGH OxyExact 2200, with a measurement precision made possible by Servomex’s paramagnetic cell technology that enables an oxygen measurement that is totally unaffected by other gases in the monitor stream. The SERVOPRO 4210 gas purity analysers will monitor the level of specific impurities in pure hydrogen and pure carbon monoxide respectively, with one unit monitoring a pure hydrogen stream for trace carbon monoxide and other 4210-based system monitoring for the presence of methane in carbon monoxide. Finally three k1550 katharometer analysers will monitor the hydrogen purity and the quality of carbon monoxide supply to the TDI process by checking the level of residual hydrogen remains between 0 and 1 %.
Each Servomex gas analyser will be installed in its own cubicle with an appropriate sampling system and all necessary pipework, ready for connection in the appropriate area of the plant.
In addition to Servomex’s experience in offering reliable and accurate process analysers suitable for different and tough applications, Chematur selected Servomex on proven experience in the design and build of TDI analyser systems, as well as the ability to provide industry-best levels of service and support to the project.
“TDI production is by its nature a complex process, so Servomex is delighted to have been selected once again by Chematur to supply this gas analyser system through OmniProcess AB,” says Servomex md Chris Cottrell. “We have been chosen not simply on the acknowledged quality of our instruments, but in our ability to deliver a complete gas analysis solution that ranges from the design and build of the system to providing ‘local-for-local’ service and support in India.”
The TDI plant is scheduled for completion in September 2010.
Hydrogen cyanide
Three Honeycat air pollution control systems designed for the abatement of hydrogen cyanide gas from the reduction process of a carbon fibre manufacturing plant have been installed by UK air pollution control specialist AirProtekt. The Honeycat systems comprise a compact skid-mounted oxidiser designed to comply with the environmental emission limits demanded by the carbon fibre plant’s local regulatory authorities and minimise on-site installation time.
“The textile processing project required an air pollution control system that was very much proven on this process. The solution AirProtekt opted to use has proved effective for over 30 years in various applications worldwide. The air pollution control system featured gas tight sealing to prevent localised emissions of toxic hydrogen cyanide gas. Mindful of the local people living in nearby residential properties the system needed to be both highly effective at capturing and treating the hydrogen cyanide emissions as well as being very quiet in operation to avoid noise pollution,” explained Trevor Lawton, AirProtekt’s md.
A very low maintenance solution, the electrically pre-heated abatement system is designed to be capable of running at low catalyst operating temperatures which helps to minimise running costs, thermal stress and ensures a long operating life.
“The project’s consultant recommended our equipment to the end-customer because he had been impressed with AirProtekt’s proven track record in working with catalyst technology used on similar process applications around the world,” said Lawton
Generally, the wall thickness of Coriolis measuring tubes are significantly less than the associated process piping, which will tolerate a higher rate of corrosion before failing. This is an area where wetted material selection for a Coriolis meter is critical.
Tantalum has been used by some Coriolis manufacturers in the past, but the twin bent tube designs made these expensive. This was due to the flange, flow splitter as well as the measuring tubes all being made from Tantalum.
It was not until the advent of the single straight tube design, that the material looked more attractive, due to the design now only needing the measuring tube and the raised face of the process flange to be made from Tantalum. This brought major cost advantages over the equivalent bent tube designs, but was not easy to achieve as Tantalum does not have the same tensile strength as Titanium which is traditionally employed.
KROHNE has been granted several patents for perfecting the technology of containing the stress created in a straight tube due to thermal expansion and are now in a position to make this technology available to highly aggressive and corrosive chemicals.
The Tantalum used by KROHNE is an alloy called Tantalum Ta10W, which is made up of 10% Tungsten and 90% Tantalum. KROHNE have found that it is the ideal material for use in its OPTIMASS 7300 mass flowmeter as Tungsten provides the additional tensile strength required to handle the stresses associated with straight tube technology.
With the addition of Tantalum, KROHNE can now offer a wide range of wetted materials for most chemicals. This now includes in addition, Hastelloy® C22, Duplex SS 318, Titanium as well as SS316L.
Silicon Laboratories created an ac current sensor family that replaces traditional current transformers. Silicon Labs’ new Si85xx ac current sensors provide up to 5 kVrms of electrical isolation to ensure safety compliance for a variety of critical power delivery systems such as ac-dc switching power supplies, isolated dc-dc supplies, motor control applications and electronic lighting ballasts.
In various industrial and test & measurement processes, bi-directional flow presents difficult challenges for flow metering equipment. For example, utility pumping and circulating plants pump dielectric fluid into underground electrical cables in order to dissipate heat generated by high-voltage power lines. This application involves monitoring upstream and downstream flow rates. It also requires a precise method of viscosity compensation as the dielectric temperature changes.
A new family of turbine flow sensors now available from Clark Solutions features innovative infrared technology to provide high-resolution flow measurement. Clark Solutions’ new PFA Turbine Flow Sensors are designed for monitoring and controlling corrosive or aggressive fluids, including fuels. PFA Flow Sensors are designed for full-scale flow ranges of 2.0 l/min, 20 l/min & 40 l/min with an accuracy of 1% of reading and a repeatability of better than 0.15%.
US company H2scan has developed inline, solid-state palladium-nickel based sensors that are highly selective to hydrogen, do not require oxygen to operate, and can detect hydrogen in concentrations from a few ppm to 100%.
Complete gas analysis
