A Short Video Explaining Refraction

Inline Refractometers Used in Commercial Food and Beverage Production

Refractometers assist in consistent quality
in commercial food and beverage processing.

All commercial food brands must assure a level of quality their users have grown to expect. A change in their product's quality can trigger a change in the customer's buying habits. The ability to provide consistent quality and taste is key to happy customers and continued sales.

For producers of many commercial food products, such as wine, fruit juice, jams, and carbonated beverages, a critical way to control quality is by measuring "Brix".

Brix is a unit of measurement used to to establish the concentration of sucrose and other sugars (as well as other dissolved solids) in aqueous solutions. When evaluating sweetness, one degree Brix (symbol °Bx) is defined as 1 gram of sucrose in 100 grams of solution, and represents the strength of the solution as percentage by mass.

Inline refractometers provide commercial food,  juice and wine producers critical information about the make-up of their product. Many commercial food processing plants use refractometers to blend their products to consistent Brix level, thus assuring consistency. Because the dissolution of sucrose and other sugars in a solution changes the solution’s refractive index, measuring this change can be used reliably to measure consistency and quality. A refractometer works by shining an LED light source from a range of angles, through a product sample, onto a prism surface. By measuring the difference in the reflection and refraction of the light source, a critical angle can be determined and the refractive index can be accurately calculated.  This measurement and calculation can be done accurately, repeatably, and with speed, so inline refractometers have proven themselves reliable instruments for the measurement of Brix in all food processing applications.

Typical applications for the measurement of sucrose, fructose, and dextrose by an inline refractometer:

• Soft drinks, fruit juices, dairy.
• Apple sauces, jams and jellies.
• Beer wine, coffee, and tea.
• Vegetable oils.
• Tomato pastes and sauces.
• Honey.

For any questions about the use of refractometry in food and beverage processing, contact Electron Machine Company at 352-669-3101 or visit http://www.electronmachine.com.

What is Refraction?

Diagram 1

Light rays travel through space in a straight line at approximately 300,000 km/s. As light passes through a transparent medium, such as water or glass, its speed is decreased.

For glass, its reduced to 200,000 kilometers per second, and for water the speed is 225,000 kilometers per second.

If the light enters into a medium perpendicular to the surface, it passes straight through but at a slower speed. However if the light beam arrives at the medium surface at an angle, not only will it speed be reduced, but it will bend due to a process called refraction.

To better visualize this phenomenon let's look at Diagram 1. As a beam of light reaches the surface of a medium the lower portion enters first and is slow down. However, the upper portion is still traveling at the speed of light until it arrives at the surface and enters.
 
This speed difference at the top and bottom aspects of the light path causes it to pivot, bending toward what is referred to as the normal. This is an imaginary line drawn perpendicularly to the surface of the material.
   
Transparent materials have what is called a refractive index. This is the speed at which light travels in a medium compared to like traveling in a vacuum.
     
For example, typical glass has a refractive index of 1.33. This is calculated by dividing the speed of light in a vacuum (300,000 km/s) by the speed of light in glass (225,000 km/s).
     
The refractive index of air is 1.0003. Anytime a light beam travels from a medium with a low index of refraction, like air, to a medium with a higher index of refraction, like glass, the beam of light will bend toward the normal.
     
Likewise when the beam of light exits a highly refractive medium into a medium with the low index of refraction, the process is reversed.
     
The bottom portion of the beam of light exits first, and resumes at the speed of light, with the top portion still at the speed determined by the medium. This causes the beam to pivot away from the normal line.

The World's Most Rugged Inline Process Refractometers

Electron Machine manufactures the world's most rugged industrial, in-line refractometers used in pulp & paper processing, chemical production, and food and beverage processing.

The company is renowned for manufacturing industrial inline refractometers that hold up to the rigorous environments and the steady demands in these applications. These refractometers are built to withstand the most harsh conditions while delivering reliable and consistent readings and providing safe, reliable, and accurate process measurement and control.

Electron Machine inline refractometers are used in numerous applications in the paper industry such as black liquor, and green liquor sensing; in the food industry to detect sugar levels and properties of jams juices, beverages, and dairy product; and in the chemical industry to measure the strength of a chemical when diluted with water or another chemical.

For more information, visit http://www.electronmachine.com.

Industrial Refractometry: The Very Basics

Most objects can be evaluated quantitatively and qualitatively. Determining the number of cars on a highway is a quantitative calculation; determining the color of a car is a qualitative calculation. In the process control industry, analyzing the qualitative and quantitative natures of a product is one of the most important steps in ensuring a manufacturer is delivering their clients not only the best product, but making sure that every product made is the best product.

If you’ve ever cracked open a crisp, cold beer on a Sunday, sampled a great wine, or asked yourself, “why does this soda taste so good?” you’ve had experience with what the process control industry calls “industrial refractometry.” Pink Floyd’s album cover for Dark Side of the Moon, where a beam of light hits a prism at a certain angle and then exits the other side in multiple colors, illustrates a core component of refractometry. Refractometry measures the speed at which light passes through an object.

Here’s how evaluating a substance with a refractometer works: a substance is placed on top of a prism. Then, a beam of light shines through the prism and reflects through the substance. The refractometer compares how much slower (or faster) light travels through the object compared to the speed of light through air. The comparison allows the evaluator to determine qualitative aspects of the substance, such as the density or concentration. For standardization purposes, the speed at which light passes through air has a refractive index (RI) value of 1. If a substance has an RI value of 1.16, light travels 16% quicker through air compared to the substance on the prism. Depending on the color and temperature of the reflected light, even more qualitative characteristics of the substance can be determined.

Electron Machine Inline Industrial Refractometer

While the process won’t always help determine what exactly a substance is (different substances can have the same RI values), refractometry is essential in determining how something is. If a corporation knows the RI value of a liquid product, they can ensure each iteration of said product is precisely made, quantitatively and qualitatively. When two substances are being combined to create one resulting substance, refractometry can show exactly how close the combined substance is to being an accurate fusion.

Overall, refractometry is used by industrial companies as a control method. Industry professionals use refractometers to perform evaluations; these refractometers range from small, hand-held devices to full-powered, computer-controlled precision machines which measure the quality of every product coming out of on an assembly line. Refractometry is an objective way to prove standards are being met while achieving production excellence, making refractometry an extremely valuable tool for industrially geared businesses of almost every size.

So, the next time you want to combine coffee and creamer, if you know the refractive value of the best cup of coffee, you could use your own refractometer to measure how close you are to the perfect morning blend!

Control Boiler Cleaning Chemicals with Inline Refractometry

Inline industrial refractometer for boiler cleaning acids.

Chemical cleaning has been considered a necessary part of boiler maintenance for many years. The objective of a chemical cleaning is to safely remove all the deposits from the inside of the boiler tubes. Proper chemical cleaning removes deposits from the inside of boiler tubes which improves the boiler heat rate, reduces tube failures and improves the stability of boiler chemistry. However, chemical cleaning can cause severe damage to the boiler if proper chemical dilution is not maintained.

The MPR E-Scan allows chemical cleaning companies the ability to control acid dilution to strict specification. This insures the proper cleaning dilution is achieved while reducing the risk of over shooting the target control point causing costly damage. By installing the instrument in-line after the dilution point, the MPR E-Scan provides real time control, trending and data logging information to operators insuring the required chemical dilution is achieved and remains constant. This will reduce the overall time needed to meet target dilution, saving time and minimizing the boiler downtime.

The MPR E-Scan can be constructed of various alloys to ensure a long service life in a harsh chemical environment. By utilizing the instrument to control and monitor the cleaning solution, chemical cleaning companies can assure customers that proper dilution was met and maintained. When the job is completed, the cleaning company can provide their customer with documentation of both the process dilution and temperature throughout the entire cleaning process.

Application Features:

• Measurement and temperature output with data logging
• Continuous accurate control of acid dilutions to meet target
• Trend graphing
• Functional status indication of monitored parameters Error and Warning light indications
• Time reduction
• High-resolution color display 

Additional design features:

• Data logging documentation for dilution and temperature
• Multiple product ranges and configurable set points.
• Sapphire Prism
• Daylight visible color display
• NEMA 4X
• Stainless-steel CNC machined sensing head
• 4-20mA & RS-232 outputs
• Configurable alarm points: high/low, setpoint/ deviation, etc. 

Refractometry: A Basic Understanding and Common Uses

A ray of light being refracted in a plastic block
(Courtesy of Wikipedia)

Refractometry, a combination of physics, materials, and chemistry, is the process which measures the composition of known substances by means of calculating their respective refractive indexes (RI). RIs are evaluated via a refractometer, a device which measures the curve, or refraction, resulting when the wavelength of light moves from the air into and through a tested substance. The unitless number given by the refractometer, usually between 1.3000 and 1.7000, is the RI. The composition of substances is then determined when the RI is compared to a standard curve specific to the material of the substance. There are also four separate types of refractometers: digital, analog, lab, and inline process. Although refractometry can measure a variety of substances, including gases and solids, the most common category of known substances to calculate are liquids; the inline process refractometer is used to quantify the makeup of liquids.

Refraction of a light ray
(courtesy of Wikipedia)

The ultimate focus of industrial refractometry is to describe what is in a final product or output of a process step. A field which relies directly on the results of refractometry is gemology. Gemological refractometry is crucial for accurately identifying the gemstones being classified, whether the gemstones are opaque, transparent, or translucent.

Other common examples of industrial refractometry uses are measuring the salinity of water to determine drinkability; figuring beverages’ ratios of sugar content versus other sweeteners or water; setting eye-glass prescriptions; understanding the hydrocarbon content of motor fuels; totaling plasma protein in blood samples; and quantifying the concentration of maple syrup. Regarding fuels, refractometry scrutinizes the possible output of energy and conductivity, and for drug-testing purposes, refractometry measures the specific gravity, or the density, of human urine. Regarding food, refractometry has the ability to measure the glucose in fruit during the fermentation process. Because of this, those in food services know when fruit is at peak ripeness and, in turn, also understand the most advantageous point in the fruit’s “lifetime” to put it on the market.

The determination of the substance composition of the product examples listed above all speak to the purpose of quality control and the upholding of standardized guidelines; consumers rely on manufacturers not only to produce these products but also to produce these products consistently and identically every single time. Therefore, the success of commercialism, etc. is dependent on maintaining the standards for the composition of substances, i.e. industrial refractometry.

Equipment manufacturers have developed numerous refractometer configurations tailored to specific use and application. Each has a set of features making it the advantageous choice for its intended application.