Sensirion Flow Meter Addresses Milliliter Applications
August 16, 2010 by Randy Frank
Filed under Featured, Flow
For flow rates below 100 ml/min, Sensirion’s SLQ-HC60 flow meter provides a reliable and inexpensive solution for automated systems and other applications. Using its CMOSens Technology that integrates signal conditioning circuitry and microelectromechanical systems (MEMS) structures in a CMOS microchip, Sensirion’s SLQ-HC60 flow meter provides a 0–10V analog output signal from a supply voltage of 24V. With typical repeatability of 1 to 2%, the typical response time is less than 50 ms. The flow channel of the sensor has an inside diameter of 1.8 mm that allows a connection to 1/8” or 3-mm plastic hoses via threaded couplings.
For more information about the Sensirion SLQ-HC60 flow meter, click here.
Honeywell Zephyr Digital Airflow Sensors Provide 2.5% Accuracy
July 12, 2010 by Randy Frank
Filed under Featured, Flow
Using a microelectromechanical system (MEMS) sense die and an Application Specific Integrated Circuit (ASIC) for signal conditioning a
nd interfacing, Honeywell’s Zephyr Digital Airflow Sensors achieve 2.5% accuracy. The fully calibrated and temperature compensated HAF Series are available in standard flow ranges of ±200 SCCM and ±1000 SCCM.
The MEMS design has thermally isolated heater and temperature sensing elements, providing a fast response to air or gas flow. The ASIC provides an I2C digital output to simplify interfacing to microcontrollers. A 3.3 Vdc voltage option, low power requirements and small size make the units well suited for battery-powered and portable applications.
For more information about Honeywell Zephyr™ Digital Airflow Sensors, click here.
RotorFlow® Sensors Combine Continuous Fluid Flow Sensing with Visual Indication
Plainville, CT – Gems Sensors & Controls introduces the RFO type of the RotorFlow Series of fluid flow sensors. RFO stands for “RotorFlow Output”, and is designed for flow rate monitoring or metering applications. RotorFlow RFO type sensors provide a pulsed DC voltage output that is proportional to the rate of flow. The 4.5 to 24VDC pulsed output is easily integrated into most digital logic units. What makes RotorFlow sensors unique is the highly visible paddlewheel that provides verification at a glance to confirm that fluids are moving. Typical applications for RotorFlow RFO type sensors include water purification, dispensing systems, chemical metering, laser and welders, semiconductor processing, water injection systems, and chillers and heat exchangers.
As liquid passes through the RotorFlow RFO body, a magnetic rotor spins at a rate proportional to flow. The magnetic fields turning with the rotor excite a static Hall Effect sensor, located in the body, and generate a series of voltage pulses. The output pulse voltage is equivalent to input (4.5 – 24 VDC), with a frequency proportional to the flow rate. Digital rate meters, totalizers, and other electronic controllers then utilize the output signal. A subset of the RFO type RotorFlow sensors is the RFA Type. These use the same operating principle, but instead of outputting a voltage pulse they are conditioned to provide an analog output signal of 0-10 VDC.
RotorFlow sensors are offered in ¼” to 1” port sizes, and monitor fluids with flow rates ranging from 0.1 GPM to 60 GPM (0.4 LPM to 227 LPM). Accuracy is dependent on model and flow range selected, and is typically within ±7%. RotorFlow sensors combine their high visibility rotors with solid-state electronics that are packaged into compact, panel mountable housings. Housing bodies are available in brass, stainless steel or polypropylene. Brass and SS bodies provide operating pressures (@ 70°F/21°C) to 200 psig (13.8 bar), while polypropylene allows 100 psig (6.9 bar). Maximum media temperature for polypropylene models is 180°F (82°C), and with brass or SS bodies is 212°F (100°C).
Gems Sensors & Controls
www.GemsSensors.com
Flow Sensor From PKP Built for Low-Viscosity Liquids
PKP Process Instruments, A manufacturer and distributor of a wide range of process instrumentation introduced its model DR05 Flow Meter.
Model DR05 paddle-wheel flow sensors are used wherever the flow of liquids having low viscosities must be reliably and economically measured, including but by no means limited to, cooling systems, demineralized water and aggressive/caustic liquids in the chemical industry.
The DR05 paddle-wheel flow sensor measures the flow of water and substances similar to water. The flow sensor consists of a section of polypropylene pipe fitted with a paddlewheel. The paddle wheel, which extends into the area of flow, is set into rotation by the flowing liquid. The rotary motion is detected by a Hall sensor and output as a series of pulses. The output frequency of these pulses is directly proportional to the flow rate. Alternatively, the pulsed output can be converted into an analog signal (4 to 20 mA) or into two limit contacts by optional integrated electronics. DR05 paddle wheel flow sensors are made completely of plastic; they have no metal parts. Wetted materials include a PP housing, ECTFE rotor and ceramic axels and bearings. Viton seals are standard (EPDM optional).
These devices are available for pipe sizes of 1″ to 2″ with turndown ratios of up to 50:1.
Flow Sensor Ideal For Geothermal Applications
The new flow sensor launched by Clark is ideal for solar and geothermal hot water systems and equipment.
DN Series Flow Sensors are very accurate at low cost. Their accuracy is to 1% fs of measured value and are available for less than $100 in quantity.
To assist documentation of energy transfer in water & water glycol based heat exchange systems, DN Series Liquid Vortex Flow Sensors provide direct temperature measurement.
The new DN Series Flow Sensors operate on the principle of Kármán’s vortex trail and can be used for flow ranges from 0.9 to 150 liters per minute. Vortex-shedding flow meters were named after Theodore von Kármán’s mathematical description of the phenomenon. They present the flow in a pipe with an obstruction/bluff in the flow meter body.
Alternating vortices are formed on each side of the bluff body as velocity increases, and travel downstream.
DN series flow sensors use piezoelectric sensors embedded in an ETFE vane located downstream of the bluff to detect the generated vortices. Flow velocity is given by the frequency measured. The measurement result is not dependent on temperature and pressure loss is minimal. A flow factor is provided to convert frequency to volume flow rate for each model size. The series offer versions with a 1000 Ohm RTD temperature sensor built-in to the bluff, providing direct temperature measurement in the medium.
Fluid Sensor Ideal For Medical Applications
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.
Pressure Sensor Designed For Pneumatic Applications
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.
Liquid Sensor Has No Moving Parts
January 23, 2010 by admin
Filed under Flow, Level, Liquid Level
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.
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Ultrasonic Sensor for Smart Meters Aid Conservation
December 23, 2009 by admin
Filed under Flow, Ultrasonic
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.
Sensor Family Replaces Transformers
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.
