Ultrasonic Flowmeter, What is It?
April 9, 2009 by admin
Filed under buy-smart-guides
A standard flowmeter either uses a float or a paddlewheel to measure flow. In order to work, fluid is passed through the flowmeter which either spins the paddlewheel or pushes a float. For installation either you cut into the pipe to attach the flowmeter or you have a branch off to use a floater flowmeter.
Ultrasonic flowmeter is different. This flowmeter will work with any sound conducting liquid. The ultrasonic flow meter is placed near the application and two clamp-on “transducers” are placed on either side of the pipe. To detect flow through a pipe, ultrasonic flowmeters use acoustic waves or vibrations of a frequency. Depending on the design there are two ways of measuring flow, either Doppler or Time-transit.
The Doppler method sends a signal and measures the change in frequency from one sensor to the next then using a mathematical formula converting into a digital flow rate.
With Time-transit the transducers produce sound waves that bounce within the pipe. The ultrasonic flowmeter measures the time it takes for the sound wave to return.
What are the benefits of a ultrasonic flowmeter?
There is No moving parts and less chance of breaking down. No paddle wheels or floats to break and replace. No wetted materials, nothing touches the liquid it’s measuring. Ultra Sonic Flowmeters work with clean and dirty fluids. Since the flowmeter measures with sound frequencies, the liquids can have solids and still keep an accurate measure of flow. The ultasonic flowmeter is best suited for corruptible liquids that eat away plastics. For example sewage, slush and beverages, where the standard flowmeter just can not cut it. It’s the perfect flow meter.
|
McPhee Enterprises has a large selection of blue white flowmeters including Ultrasonic Flowmeters. Article Source: http://EzineArticles.com/?expert=Brad_Burnie |
Ultrasonic Level Sensors
April 9, 2009 by admin
Filed under buy-smart-guides
Ultrasonic level sensors (sometimes called sonic) are ideal for non-contact level sensing of highly viscous liquids such as heavy oil, grease, latex, and slurries as well as bulk solids like cement, sand, grain, rice, and plastic pellets They are also widely used in water/waste water applications for pump control and open channel flow measurement. The sensors emit high frequency, “ultra” sonic (20 kHz to 200 kHz) acoustic waves that are reflected back to and detected by the emitting transducer.
Since the speed of sound in air fluctuates with moisture level and temperature, ultrasonic level sensors are also affected by changing moisture levels and varying temperatures and pressures inside the hopper or container. But when ultrasonic sensors are used in conjunction with humidity and temperature sensors, or a distance reference, correction factors can be applied to the level measurement making the technology very accurate.
Turbulence, foam, steam, chemical mists (vapors), and changes in the concentration of the process material also affect the ultrasonic sensor’s response. Turbulence and foam prevent the sound wave from being properly reflected to the sensor; steam and chemical mists and vapors distort and/or absorb the sound wave; and variations in concentration cause changes in the amount of energy in the sound wave that is reflected back to the sensor. Stilling wells and wave guides are used to address some of the above constraints.
Proper mounting is important to ensure that sound waves are reflected perpendicularly back to the sensor. Otherwise, even slight misalignment of the sensor in relation to the process material reduces the amount of sound wave detected by the transducer. In addition, the hopper, bin, or tank should be relatively free of obstacles such as weldments, brackets, or ladders to minimise false returns and the resulting erroneous response, although most modern systems have sufficiently “intelligent” echo processing to make engineering changes largely unnecessary except where an intrusion blocks the “line of sight” of the transducer to the target. Since the ultrasonic transducer is used both for transmitting and receiving the acoustic energy, it is subject to a period of mechanical vibration known as “ringing”. This vibration must attenuate (stop) before the echoed signal can be processed. The net result is a distance from the face of the transducer that is blind and cannot detect an object. It is known as the “blanking zone”, typically 150mm – 1m, depending on the range of the transducer.
The requirement for electronic signal processing circuitry can be used to make the ultrasonic sensor an intelligent device. Ultrasonic sensors can be designed to provide point level control, continuous monitoring or both. Due to the presence of a microprocessor and relatively low power consumption, there is also capability for serial communication from to other computing devices making this a good technique for adjusting calibration and filtering of the sensor signal, remote wireless monitoring or plant network communications. The ultrasonic sensor enjoys wide popularity due to the powerful mix of low price and high functionality.
Ultrasonic Flowmeter, What is It?
March 9, 2009 by admin
Filed under What's Hot
A standard flowmeter either uses a float or a paddlewheel to measure flow. In order to work, fluid is passed through the flowmeter which either spins the paddlewheel or pushes a float. For installation either you cut into the pipe to attach the flowmeter or you have a branch off to use a floater flowmeter.
Ultrasonic flowmeter is different. This flowmeter will work with any sound conducting liquid. The ultrasonic flow meter is placed near the application and two clamp-on “transducers” are placed on either side of the pipe. To detect flow through a pipe, ultrasonic flowmeters use acoustic waves or vibrations of a frequency. Depending on the design there are two ways of measuring flow, either Doppler or Time-transit.
The Doppler method sends a signal and measures the change in frequency from one sensor to the next then using a mathematical formula converting into a digital flow rate.
With Time-transit the transducers produce sound waves that bounce within the pipe. The ultrasonic flowmeter measures the time it takes for the sound wave to return.
What are the benefits of a ultrasonic flowmeter?
There is No moving parts and less chance of breaking down. No paddle wheels or floats to break and replace. No wetted materials, nothing touches the liquid it’s measuring. Ultra Sonic Flowmeters work with clean and dirty fluids. Since the flowmeter measures with sound frequencies, the liquids can have solids and still keep an accurate measure of flow. The ultasonic flowmeter is best suited for corruptible liquids that eat away plastics. For example sewage, slush and beverages, where the standard flowmeter just can not cut it. It’s the perfect flow meter.
|
McPhee Enterprises has a large selection of blue white flowmeters including Ultrasonic Flowmeters. Article Source: http://EzineArticles.com/?expert=Brad_Burnie |