What would be the best refractometer for Amil?

1. Brix refractometer with automatic temperature compensation, such as model 81150-06.
2. Palette-style Brix refractometer with digital display and automatic temperature compensation, such as model 02940-62.
3. Salt refractometer such as model 02940-43.
4. Wine refractometer with automatic temperature compensation and a 0 to 25% T.A. range, such as model 02940-68.

See the answer.

Cleaning the tanks is also a simple task. Initially, Dom thought the absence of a bottom manway would be a problem. However, Dom says “for the price of a bottom manway on a stainless steel tank, that you may only use a few times a year, the price isn’t worth it.”

Here’s how they handle the cleaning. They do a lot of whole fresh fruit (other than grapes) that they crush into the tanks. The fruit ferments on the pulp. “After fermentation we rack the wine into clean tanks and merely tip the tanks over and scoop out the pulp (pomace). This takes 15 minutes with another 10 minutes to wash out the tank with hot water and a splash of bleach (chlorine)”. They also use a 6 foot stainless 2” pipe attached to their wine hose and pump to draw out the bottom wash liquid. Some people are concerned about flavor pick up from the plastic. Dom says “There is absolutely no flavor pick up. If there were our customers would tell us. Last year we produced 3500 cases of wine for our first year of business, including wine for 6 other wineries. No one had any complaints. Of about 10,000 visitors to our winery last year only a handful commented on the tanks in a negative manner. Once we told them of the benefits of the tanks they became converts to plastic.”  In summary, polyethylene tanks can give wineries savings in tank costs over stainless steel and the portability can reduce the number of buildings required. Snyder’s high density linear polyethylene tanks are also molded from 100% FDA approved materials and are safe for storage of food products.

Complete Selection of Cone Bottom Tanks
Complete Selection of PIE 520 Thermocouple Simulators
Complete Selection of Polyethylene Tanks

Published with permission from Snyder Industries Inc.

If you bought a Butterball turkey this Thanksgiving, you have particle accelerators to thank for its freshness. For decades now the food industry has used particle accelerators to produce the sturdy, heat-shrinkable film that Butterballs come wrapped in.

“Particle accelerators tie the molecules of plastic together and make the film tougher mechanically. It doesn’t crack or tear,” says Marshall Cleland, a technical advisor at IBA Industrial, an international company that has been manufacturing particle accelerators for commercial use since 1988.

Understanding how accelerators give cross-linked shrink film its unique properties requires a refresher course in chemistry.

Heat-shrinkable film—commonly known as shrink wrap—is made of polyethylene plastic. The plastic molecules, called polymers, are long chains of carbon atoms strung together like pearls. Each carbon atom also connects with two hydrogen atoms, leaving it no room to bond with anything else.

“The fully saturated carbon had its full meal, including dessert, and becomes chemically inert,” Cleland says. “If you heat it to the boiling point of water, it will turn into a syrupy mess.”

However, when hit with a beam of electrons from a particle accelerator, the plastic’s polymer strings become chemically active.

The electron beam knocks hydrogen atoms off the polymer chains, leaving the polymers hungry to fill those vacancies. If conditions are right, the carbon atoms in one chain bond with carbons in neighboring chains—and those carbon-carbon bonds are incredibly strong.

“The whole thing starts to knit together. Instead of being loose threads, it is sort of like a fishnet where everything is tied together,” Cleland says. “It is what we call a cross-linking reaction.”

When fully cross-linked, the plastic “becomes elastic if you heat it to boiling temperature, but it won’t melt,” Cleland says. After electron-beam treatment, the plastic is stronger and more heatresistant. It can be heated and stretched into a thin film without ripping. When cooled to room temperature, the cross-linked plastic retains its expanded shape. Place something inside it, such as a Butterball turkey, and apply heat, and the plastic shrinks back down to its original size, resulting in an air-tight wrapping.

The food industry purchases these cross-linked products from plastic manufacturers in large rolls or bags, depending on how the film will be used. You will find cross-linked shrink film wrapped around many items in the grocery store, such as turkeys, produce, and baked goods, as well as around board games, video games, DVDs, and CDs. “It’s a big business,” Cleland says.

Complete Selection of Chemical Property Testing

Published with permission from Symmetry Magazine, A joint Fermilab/SLAC publication

What would be the best meter for his application?

1. CheckMate II O2 benchtop analyzer (model 86490-20) measures from 10 ppm to 100% with an accuracy of 1% of reading, and it can log more than 10,000 test results.
2. Handheld O2 analyzer (model 10360-20) measures from 0.1 to 100% with 1% accuracy, and has no datalogging capability.
3. CheckPoint O2 analyzer (model 86490-00) measures from 0 to 100% with 0.1% from 0 to 5% and 2% from 5 to 100%. It also stores up to 10 readings to be recorder later.
4. Benchtop O2 analyzer (model 10360-60) measures from 0.1 to 100% with 0.1% accuracy; has no datalogging capability.

See the answer.

Quest Technologies® NoisePro Personal Dosimeter DL

SOUND DEFINED
When you blow up a balloon you are using your lungs to force air into the balloon. This causes the balloon skin to expand into its stretched out shape. The air in the balloon is now under pressure. If we squeeze the balloon in the middle, what happens? The balloon bulges out at the ends and the pressure inside the balloon increases. When the balloon is released it pops back to its original shape at its original pressure.

Suppose the balloon were very long and someone squeezed it at one end. What would we observe at the other end? First we would notice that nothing happened for a short period after it was first squeezed, then, just like the small balloon, the pressure would increase. What is happening is that the excess pressure caused by the squeeze is traveling down the tube at a speed of about 1200 feet per second. This excess pressure is the sound wave. If the squeeze were released, a decrease in pressure would travel down the tube in the same manner. To convince your self that these actions actually produce sound waves, burst the balloon with a pin.

How do we describe sound? Consider something that appears not to have anything to do with sound at all: a weight hanging from a spring.

If we pull the weight down a certain distance from the point it naturally hangs, then release it, the weight starts returning toward the rest position. But it goes through the rest position until it reaches a point as high above the rest position as it was pulled below it. The weight then starts down again to a new lowest position, where the process repeats over and over. Since the energy source of the person that initially pulled down on the weight is gone, the weight rises and falls a smaller distance each time, eventually coming to rest once again. The maximum displacement from the “at-rest” position is called the amplitude, and the time it takes to go through one complete cycle (from down to up to down) is called the period of the vibration. The number of periods that occur in one second is called the frequency. The units of frequency were once called cycles per second, but are now called Hertz and abbreviated “Hz”. So what’s the correlation between a weight on a spring and sound in air? Look at a stereo speaker emitting a single tone. As the speaker cone moves forward and backward like the spring, it alternately compresses and expands the air in front of the cone. The compression and expansion then moves out away from the speaker as a sound wave.

Single Frequency Sound
There are a number of common sources of sound that act much like the spring because they cause a single frequency sound to be produced. The keys of a piano are a good example. Pressing the middle C key causes its string to vibrate about 260 times per second. The vibrating string and soundboard cause the air adjacent to it to compress and expand with the same frequency. Just like the balloon, the changing pressure moves outward as a sound wave. Other examples of tones are the hum of a motor (60 Hz) and the sound of a police whistle (3500 Hz).

Random Motion–Noise
Suppose instead of just pulling the spring down and releasing it, there is an invisible hand that randomly either pulls or pushes on the weight at different times. Sound can behave in this random manner as well – think of music. So how would you describe this motion? Certainly there is no single frequency or amplitude with which to describe the motion as in the previous case. Fortunately noise such as this can be shown to consist of many single frequency components, each having its own amplitude.

Sound With Many Frequency Components
As an example of sound with many frequency components, consider motorcycles and automobiles. The amplitude of sound from motorcycles is typically greater than for automobiles. Motorcycle sound also contains components that are higher in frequency than an automobile. These are two reasons why motorcycles annoy people more than automobiles.

The Decibel
How do we describe the volume of sound we hear in everyday life? Because the sound levels we encounter in daily life can vary over such a wide range, talking about sound pressure in units such as pounds per square inch would be unwieldy. To remedy this situation we define Sound Pressure Level (SPL) as:

SPL = 20 x logarithm10 (measured sound pressure / reference sound pressure)

The reference pressure used for environmental noise turns out to be the lowest level sound that a person with normal hearing can detect. The unit of SPL is called the decibel (dB). Does all this complicated jargon mean that an enforcement officer will have to have a degree in mathematics? NO! All enforcement equipment is calibrated directly in decibels, so no calculations are involved.

Sound Level And Distance From The Source
Most people know that noise levels increase as you get closer to a sound source and decrease as you move away. It is important to note that the sound pressure level rises at a faster rate as you move closer and at a slower rate as you move away. Think about what happens when you drop a stone in water. The waves that are created are closer together and higher (amplitude) nearer the point of impact and further apart and lower as you move away from where the stone entered the water. Sound pressure behaves in the same manner. The importance of this observation is that officers should make sure he/she is at least as far away from the source as your ordinance requires when taking sound measurements. It is better to be a little too far than a little too close.

Combining Sound Pressure Levels
Suppose we have two identical sound sources, each alone producing the same dB level. So what is the SPL of the combined sources? It is not the sum of the two. We cannot simply add decibels directly to get the overall effect. The correct answer is obtained by using the following rule: Each time the number of identical noise sources is doubled, the SPL increases by 3dB; each time the number is halved, the SPL is decreased by 3dB. This rule is called 3dB doubling or 3dB exchange rate.

How does the 3dB rule help you? Suppose your noise ordinance has an 80dB noise limit. You cite a violator for causing an 89dB noise level and the case comes to court. The judge asks you how loud 89 dB is. Knowing this rule of thumb, you are able to tell the judge that 89 dB is the same noise level that would be generated by 8 identical vehicles, each producing the maximum allowable sound level of 80 dB. Case closed!! Be sure to apply the doubling rule contained in your particular ordinance.

Effects Of Additional Noise Sources
A third factor to remember when measuring sound involves the contribution to the overall level of all the other noise sources present at the time a violator is cited. This extraneous noise is called the ambient level. The violator might ask, “There were a number of other loud noise sources present when you cited me, so how do you know that they didn’t cause the readings to be too high?” The rule that applies here is: a violator should not be cited unless the level measured when the violation occurs is at least 10dB above the ambient noise level immediately before the violation. If this condition is met, then the additional noise caused by all the other sources producing noise will add less than 0.4dB to the level produced by the violator.

Sound Reflection
The last factor to remember is the effect of large objects on sound reflection. Think of the stone in the water again. If the water waves encounter an obstacle as they move away from where the stone entered the water, you will see part of the wave reflected back in the direction it came from, modifying the height of the waves, which is equivalent to the sound pressure in air. The same phenomenon occurs in air when measuring sound. The rule of thumb is to remain at least as far away from any large reflecting objects as you are from the source being measured. What about reflection from the ground? The noise level limit stated in the ordinance should take into account the fact that the noise heard by the receiver consists of sound that is reflected from the ground to the receiver as well as the direct wave. Normally there should be no concern. The exception is when the sound level meter is close to the ground. All measurements should be made with the microphone at least three feet above the ground.

The Sound Level Meter
The most common device used in noise ordinance enforcement is the sound level meter (SLM). The SLM performs three basic operations. It uses a microphone to convert the energy in the sound into an electrical signal. An electronic circuit then conditions the signal to provide meaningful results. Finally, the SLM communicates the results to the operator in one or more ways.

Before we address the specifics of various kinds of meters, we should address the most basic question of all, “How should I hold the SLM?” Should the microphone be pointed at the noise source or should the face of the microphone be oriented at some other angle such as at a right angle to the sound wave? The answer depends on the type of microphone being used. There are three different types of microphones available: free-field, random incidence and pressure. Free-field microphones should typically be pointed directly towards the noise source. Random incidence microphones should typically be held at a 70° angle to the source. Pressure microphones should typically be held at a right angle to the noise source. The rule here is to follow the manufacturer’s recommendations with respect to microphone orientation. Generally, low frequency sounds are not affected by the microphone orientation as much as high frequency sounds. Again, this depends largely upon what type of microphone element is used in the SLM.

The Basic SLM
Features vary considerably from meter to meter and from manufacturer to manufacturer. Perhaps surprisingly, so can performance and accuracy. No matter what type of SLM is used, at least two requirements of the meter should always be met. These include some method for performing a field calibration of the SLM and an independent certification that the SLM meets Type I or Type II standards of performance and all other applicable SLM standards in your locality. Your noise ordinance should include a statement of standards that must be met by the meter.

In its most basic form, the SLM will provide the operator with an indication of the instantaneous SPL being detected. Often a basic meter will also provide an indication of the maximum SPL encountered as well. Results from a Basic SLM’s are almost certainly limited to presentation through the display of the meter. Rarely are there capabilities for these meters to output results to a printer or computer. There may or may not be provisions in the meter to allow the operator to change certain characteristics of the SLM’s signal conditioning circuits. These characteristics in a basic meter may or may not include the weighting network and the response time constant. Your noise ordinance should include a specification as to which weighting network and response time constant is to be used.

Weighting networks most common today consist of “A”, “C” and “Z” weighting. Each of these weighting networks is a “standard” that dictates how the SLM will recognize the amplitude of the SPL based on the frequency of the sound. For instance, “A” weighting circuits simulate how the human ear responds to sound. We know that humans can hear within a fixed range of frequencies and humans perceive that sound is louder or softer as frequency changes.

Response time constants define how quickly an instrument must be able to recognize and process changing SPL’s. The most common options today are “Fast”, “Slow”, “Peak” and “Impulse” time constants. If it were not for the existence of frequency weighting and response time constant standards, results from meter to meter and manufacturer to manufacturer would almost certainly vary widely and prohibit the effective measurement and enforcement of noise limits.

Integrating SLM’s
Depending upon the requirements of your noise ordinance, you may need an SLM that computes the average SPL over a prescribed amount of time. These types of SLM’s are referred to as Integrating SLM’s because they automatically calculate the average SPL. All Integrating SLM’s calculate this result based on a given doubling or exchange rate, as discussed earlier. Some SLM’s may be fixed for a specific exchange rate at the factory. Others may include provisions for setting the exchange rate in the field. In either event, it is important to note which exchange rate the SLM is using and that it matches the requirements of your noise ordinance. Since it is possible for ordinances to change, it is always more favorable to have an SLM that allows the exchange rate to be changed by the user without requiring factory modification, or worse yet, replacement. Integrating SLM’s may include provisions for printing results or uploading them to computer. Generally speaking, unless the meter also documents the performance of a field calibration in its output, the value of the hard copy results is greatly diminished.

Datalogging SLM’s
After integration, the next mostly commonly sought after capability in an SLM is datalogging. Datalogging SLM’s provide much more detail of the noise-testing event. This can include a minute-by-minute profile of the sound source’s SPL levels. At a minimum, these kinds of meters should provide hard-copy and computer upload of test results correlated to the real-time and date of the event.

Octave Band SLM’s and Real Time Analyzers
At the top end of the spectrum for SLM’s you will find devices that are capable of determining and reporting the SPL and average SPL at various frequencies. These meters are rarely used for noise ordinance enforcement since ordinances rarely specify noise limits as a function of frequency. Generally speaking, once frequency content of the sound is a concern, specialists in acoustics are required to perform these tests.

Complete Selection of Quest Cable-Free Noise Dosimeters
Complete Selection of Quest SoundPro Sound Level Meters
Complete Selection of Quest Technologies Integrating Sound Meters with RS-232
Complete Selection of Quest Technologies Intrinsically Safe Sound Meters
Complete Selection of Quest Technologies NoisePro Personal Dosimeters

Published with permission from Quest Technologies

Full article can be found at:  http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=Sound_Measurement.htm&ID=1183&referred_id=5618

Here is an example of how a tax estimate will appear in the shopping cart:

• Tax estimates will be shown in the shopping cart with final tax charges displayed in the checkout process.
• Both registered and non-registered users will see tax charges.
• Tax charges will only be available when we’re able to provide shipping charges.
• Shipping charges will be taxed when shipping to states that require this.
• Customers with a tax exemption certificate on file will not be charged tax when shipping to states in which they are exempt.

www.coleparmer.com

Find everything you need inside our NEW General Catalog! This 2,600-page catalog features over 60,000 products for electrochemistry, fluid handling, industrial process, laboratory research, and more. See our vast selection of hard-to-find items and everyday basics—including over 10,000 new products—from the industry’s most respected brands. 

This user-friendly CD contains everything in our printed Cole-Parmer General Catalog, plus links to our Web site for the most current product information, pricing, and availability.

Get mine today!

 

Challenge: A manufacturer of electrical test equipment noticed that circuit board failures increased during the fall and winter, and decreased during the spring and summer months. After a thorough investigation of the failures, it was determined that certain individual components on the circuit boards were damaged internally.

Which of the following actions should be taken:

1. Install a cleanroom and implement cleanroom procedures
2. Increase the number of inspections of individual components before installing them on the circuit boards.
3. Rotate component stock to see if older stock is the source of the failures.
4. Add a surge protector, as quite often a power surge will damage the circuit board.
5. Implement a static control program.

See the answer.

Temperature is one of the most frequently measured parameters in industrial processes. A wide variety of mechanical and electrical thermometers are used to sense and control process temperatures. Regular calibration of these thermometers is critical to ensuring consistent quality of product manufactured, as well as providing regulatory compliance for some industries.

 

The Basics

Most simply stated, temperature calibration consists of placing a thermometer under test into a known, stable temperature environment. A comparison is made between the actual temperature and the reading indicated by the thermometer under test and the difference is noted.

Adjustments can then be made either directly to the thermometer or to its readout. Electrical thermometers are adjusted by mathematically re-creating the coefficients used by SMART transmitters or other readout devices to translate their electrical output to temperature. Many mechanical thermometers, such as dial gauges can be adjusted by turning a dial or other mechanical device. In some cases, such as liquid-in-glass thermometers, direct adjustments are not possible and offsets must be noted.

In industrial applications, the temperature environment is usually provided by a drywell, or “dry-block” calibrator, or a micro-bath. Both offer portability and a wide range of temperatures. Drywells use high stability metal blocks with drilled wells to accept the reference and UUT. Drywells typically cover ranges from -45°C to 1200°C and micro-baths cover ranges from -25°C to 200°C. Micro-baths are similar in size to drywells but use a small tank of stirred fluid instead of a metal block. Micro-baths offer significant advantages when calibrating short or odd shaped probes.

The “actual” temperature of the bath or dry-well is determined by a reference thermometer, which may be either a thermometer internal to the heat source or an external reference thermometer operating independent of the heat source.

Figure 1: Heat source as reference standard

External or Internal Reference

Micro-baths and dry-wells have a built-in sensor to provide a feedback loop to the unit’s controller and to provide a temperature reading to the user. The manufacturer of the heat source (or a third-party laboratory) can calibrate this sensor so the unit displays a traceable temperature within a stated uncertainty. For some applications, this uncertainty level (typically ±1-2°F) is adequate. Using an internal reference is sometimes preferred because it requires fewer instruments and enhances portability for field applications. This method is illustrated in Figure 1.

The reference system, however, should be more accurate than the process system being calibrated. The generally accepted Test Uncertainty Ratio (TUR) is 4:1 (i.e. the reference should be four times more accurate than the sensor or system being calibrated). Therefore, if a process thermometer is being relied on for correct readings within ±2°F, the test system should typically be ±0.5°F or better at each temperature in question. As a general rule, temperature uncertainties are larger at higher temperatures.

Figure 2: External reference standard

Where uncertainty requirements are more rigorous, external reference thermometers help improve system uncertainty (see Figure 2). These thermometers—usually platinum resistance thermometers (PRTs) or thermistors—can often be calibrated to a few hundredths of a degree and can be read by electronic readout devices that contribute little to total measurement uncertainty. These systems can provide measurements with uncertainties as low as ±0.05°F or ±0.02°F—or better. The reference probe and readout should be periodically re-calibrated, preferably by an accredited cal lab, to assure performance specifications and maintain traceability.

Because external thermometers are more accurate, they increase the relative significance of other components of calibrations uncertainty, such as uniformity and stability. It is, of course, critical in any calibration to account for all sources of uncertainty in the process.

System or Component Calibrations

Most temperature sensors used in processes are read by transmitters, which send a 4 to 20 mA signal to a control panel, which then displays the temperature for process monitoring. Such systems involve three instruments, all of which require periodic calibration. Of these three, the largest errors are often found in the temperature sensor (which is subject to drift for a variety of reasons), so its calibration is of particular concern.

More Details or Order Online: Hart Scientific Field Temperature Dry Wells High-Temperature Field Dry Block Calibrator Industrial Dual-Block Calibrator

Several calibration methodologies are used in the process plant with the most representative method being to calibrate the complete measurement system from sensor through transmitter to indicator or controller; alternatively each component of the measurement system can be individually calibrated.

The temperature sensor can be individually calibrated using a drywell or micro-bath heat source to simulate the process temperature. If the temperature sensor is electrical, a readout device measures its output. Adjustments are then made to the thermometer or its coefficients as discussed earlier.

The transmitter is calibrated using a precision simulator to generate the resistance or voltage output from the temperature sensor and input to the transmitter. The simulator also measures the resulting transmitter current or voltage output. The transmitter is adjusted to ensure that the output follows the input, e.g. for a 4 to 20 mA transmitter with a range of 0°C to 200°C, 4 mA corresponds to 0°C and 20 mA corresponds to 200°C. The simulator provides a wide range of input and output ranges to cover all resistance thermometer and thermocouple types.

The indicator or controller is also calibrated using a precision simulator to generate simulate the resistance or current input from the transmitter. The indicator or controller is adjusted so that the display variable matches the simulated input.

The complete system is calibrated using the drywell or micro-bath to compare the reference probe and UUT. The transmitter is adjusted to ensure that the indicator or controller agrees with the reference probe readout. This calibration method is most representative of the real process, is faster and simpler to perform.

Accredited Calibration Services

Calibration of the thermometer standards used to calibrate industrial thermometers provides traceability, which means that measurements are traceable to national and international standards. Traceability to international standards ensures that measurements made in one country agree with measurements in another country, which is particularly important for companies using similar manufacturing processes at different locations around the world.

More Details or Order Online: InnoCal Calibration Services

More and more calibration labs throughout the U.S. are being accredited to international standards such as the ISO Guide 25. Accreditation ensures that a lab’s quality systems, uncertainty levels, and traceability statements have been examined and independently verified. NVLAP and A2LA are the primary accrediting bodies in the U.S. A recently signed international agreement ensures that accrediting bodies in almost every developed nation also recognize accreditations granted by NVLAP and A2LA.

In summary, process plant temperature calibrations require a good reference thermometer with readout, a drywell and/or micro-bath heat source, and a precision simulator. These instruments, in turn, should be periodically calibrated by a reputable lab, preferably one that is accredited and can prove traceability.

How to Determine Thermocouple System Accuracy
Temperature Controller Features
Temperature Conversion Equations
Temperature Instrument Ranges

View original article.

by Bernard Morris, Vice-President of Sales, Hart Scientific, Inc.
Reprinted with permission of Hart Scientific, Inc.