In-Line Process Refractometer




Refractometry, a combination of physics, materials, and chemistry, is a measurement technique which determines 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 refractive index. The composition of the substance is then determined with a comparison of the measured RI to standard curves developed for the substance. There are four general types of refractometers: digital, analog, lab, and inline process. Although refractometry can measure a variety of substances, the most common group of known substances to calculate is liquids. Liquid based continuous processes benefit from the use of an inline process refractometer to provide real time data about process output or intermediate steps.

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 include measuring the salinity of water to determine drinkability; figuring beverage 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 processing can 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 safely and in vast quantity, but to deliver the customer a consistent taste experience when the product is consumed. Brand marketing success relies on maintaining the standards for the composition of substances that comprise the product. One could argue that an in-line process refractometer is actually a marketing tool of some sort, at least to the extent that it is employed to maintain consistent product quality.

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. Product specialists can be invaluable sources of information and assistance to potential refractometer users seeking to match the best equipment to their application or process.

Ultrasonic Clamp-On Flowmeter with SIL 2 Rating

clamp on ultrasonic flowmeter with control unit SIL 2 rating
FLUXUS F/G70X and F/G80X series meters
Courtesy Flexim
Measuring the flow quantity of gases and liquids is a common industrial processing task. There are numerous technologies available for measuring fluid flow, each with its own set of advantages and drawbacks for any particular application. Some of the technologies and methods have been in use for a very long time, with recent enhancements provided by electronics or smart sensor designs.

Ultrasonic flow measurement devices employ a comparatively recent technology to measure gaseous or liquid flow. Whether the transit time differential or Doppler method is utilized, ultrasonic flow meters have a distinctive characteristic in that they can be deployed in a form factor that does not require insertion into the fluid. A common installation method is to clamp the ultrasonic transducer assembly onto the exterior of a pipe. This makes the technology attractive for applications that involve adding a flow measurement point to an existing piping system.

Flexim, a globally recognized leader in ultrasonic flow measurement, offers a number of permanent and portable units for measuring liquid and gaseous flow rates. Some of their instruments have been certified as SIL 2 capable, along with a host of other third party certifications. The product range includes simple and accurate instruments designed for general industrial use, and extends to multi-beam units intended for applications, such as custody transfer of fluids, that require the highest accuracy and overall performance levels.

Share your flow measurement challenges and requirements with instrumentation specialists, combining your own process knowledge and experience with their product application expertise to develop effective solutions.


Inline Refractometers Used in Commercial Food and Beverage Production

in-line process refractometer with control housing
Hygienic process in-line refractometer
with control unit and flow cell
Courtesy Flexim
Refractometry is a measuring technique that evaluates the impact of fluid media on light. There are some variants of the basic technology, but essentially it relies upon the media affecting a change in the way in which light waves propagate through a sample. This refraction caused by the sample can be compared to a known standard and information about the sample can be deduced.

Refractometry is a useful measuring method for many liquid processing operations. It is used for concentration and density analysis of process liquids. Portable sample processing units are available, but high volume continuous flow operations benefit from the use of in-line refractometers that do not require manual sampling and handling of process liquids. The measurements are produced in real time to continuously verify the fluid quality characteristics.

Food and beverage manufacturers use refractometry to determine the concentration of sugar, ethanol, ascorbic acid, pectin, artificial sweeteners and other components in their products. Close control of component concentration is a necessary part of delivering a consistent taste in finished products. Large investments are made to establish brand name products, and delivery of a consistent customer experience each time a product is consumed is key to developing and growing a brand. This is a solid example of a marketing based application of science and technology to industrial processing.

In-line refractometers for food and beverage applications will have specific features and construction to make them suitable for hygienic processing. The avoidance of contamination is first and foremost a requirement. Additionally, design features that reduce maintenance requirements and retain the needed measuring accuracy through extended periods of usage add value to the unit and should be a consideration when selecting an in-line refractometer.

Share your in-line refractometry applications and challenges with product specialists, combining your process experience and knowledge with their product application expertise to develop effective solutions.


Simplex vs. Duplex Strainers For Industrial Liquid Processing

duplex basket strainer
Duplex basket strainer, shown with one basket removed
Courtesy Eaton Friltration
Many industrial and commercial liquid systems have mechanical components that cannot tolerate particulate matter in the liquid. Pumps, valves, sensors, and other specialties can experience accelerated wear and tear due to certain types and sizes of particulate matter.

Good practice dictates that the tolerance of the system for particulate matter should be determined and a properly sized and configured device be put in place to remove particulates larger than greatest allowable size. Considerations for connection size and type, construction material suitability for the process media, flow rate, pressure drop, and filter holding capacity should all be a part of the product selection criteria.

simplex basket strainer with basket removed
Simplex basket strainer with access cover and basket removed
Courtesy Eaton Filtration
One key element of the selection criteria is whether the system can be temporarily shut down for replacement or cleaning of the filtration element. A basket strainer, one of several types of liquid filtration devices, is available in both simplex and duplex variants. A simplex basket strainer functions as a single unit, requiring flow stoppage when the basket becomes clogged with debris. The changeover time may not be long, but some processes cannot tolerate any downtime. A duplex strainer is comprised of two simplex strainers, incorporated into a common housing, with an inlet chamber and diverting valve that selects which strainer basket will process the liquid flow. Changes in pressure drop through the device can be used to signal when it is time to switch operation between the strainer baskets.

Fluid filtration can be an important part of keeping a process in operation, reducing wear and tear on piping system components and equipment. Share your process fluid filtration challenges and requirements with application specialists, combining your process knowledge and experience with their product application expertise to produce effective solutions.

Hybrid Solar TEG Power Systems

hybrid solar PV photovoltaic thermoelectric generator TEG power system
Hybrid system shown in remote installation
Courtesy Gentherm Global Power Technologies
There are remotely located instruments and equipment throughout the world in places without available grid power. A suitable and reliable means to provide electric power is required as a standalone system for each of these instances. Photovoltaics is an obvious choice for power source, but there is another option that may provide substantial benefit for many installations.

A hybrid solar TEG (thermoelectric generator) can overcome some of the shortcomings of a pure PV system by delivering battery charging current during conditions when solar generated power is insufficient. The TEG uses heat from burning fuel to produce electric power, and can deliver charging current when the PV portion of the system fails to provide sufficient output.

  • Extended periods of bad weather. While this scenario can be compensated for with a larger battery array, there is still a limit to the performance period. Larger battery banks increase unit cost, size and weight.
  • Extreme low temperature. Battery capacity decreases during cold weather, requiring a larger battery array to provide design power output and reserve.
  • Low solar exposure during certain times of the year, requiring more solar panels to accomodate the system power requirements during times of reduced sunlight. This increases unit size and capital cost.

Critical power systems must be designed to deliver sufficient power under all environmental conditions that can be experienced at the installation site. This drives pure PV system designers to substantially oversize panel and battery arrays to assure power delivery throughout an entire year. A hybrid solar TEG system does not need to have the enormous headroom built into the design that a pure PV does. The TEG can produce power at a known rate, regardless of the surrounding environmental conditions. The potential benefits from the hybrid power system include: 

  • Reduction in solar panel array size and cost
  • Lower battery count, with reduction in capital cost, replacement cost, unit size and weight
  • Longer battery life
  • Less on-site fuel vs. a conventional fuel-based system
  • No more than once-per-year maintenance visits
  • Increased reliability over a pure PV installation

Share your remote installation power requirements and challenges with a product application specialist and bring the benefits of a hybrid solar TEG power system to your operation.


Switching Inductive Loads With Relays and Solid State Devices in Process Control

control panel interior process automation and control panel
Switching devices must be properly protected for longevity
We connect a lot of black boxes together in our control systems, not really knowing what goes on inside. There is a basic understanding of function, but maybe not enough knowledge to thoroughly assess all aspects of integrating a device into a train of control system components. We range from novice to seasoned expert, so Acromag, manufacturer and global supplier of I/O devices for process control, has provided a useful application note regarding the protection of devices employed to switch inductive loads.

The application paper provides a good explanation of what an inductive load is, and how it can impact the performance and longevity of a switching device. The document further explains how to offset the potentially damaging impact of an inductive load on a connected switching device, with specific examples and recommendations on how to put the protective measures in place. It is useful information.

The paper is provided below. Share your I/O and other process measurement and control challenges with application specialists, combining your own process knowledge with their product application expertise to develop effective solutions.


Selecting the Right Temperature, Pressure, or Differential Pressure Switch

industrial temperature switch pressure switch differential pressure switch
Temperature, pressure, and differential pressure switches come in a wide variety of configurations
Courtesy Ashcroft
Industrial process control applications present dynamic and varied requirements for measuring, monitoring and control. Each point calls for specific evaluation of the information needed from the process point for use in monitoring process performance, or control to be applied at the process point to regulate an outcome. Sometimes, a continuous analog signal is needed to provide indication across a range of values. Other times, it is only necessary to have notification of, or take action when, a certain temperature or pressure related event occurs. In those cases, a simple and reliable device can adequately meet the project requirements.

Temperature, pressure, and differential pressure switches connect to a process and change their switch position when a setpoint condition is reached. The are simple to understand, easy to install, low in cost, and require little maintenance of attention. The switches are available in an extensive array of configurations, with options to fill out almost any application requirement.

Ashcroft, global supplier of temperature and pressure switches, has produced a simplified guide that enables a designer or specifier to quickly focus their search on the right product. It is provided below for your use. Alternately, you can always share your process measurement and control requirements and challenges with product application specialists, combining your own process knowledge with their product expertise to develop effective solutions.