Wavelength Matters

Single-Wavelength Mode FAQ

Posted by Jonathan Stronach on Thu, Jul 20, 2017 @ 11:38 AM

Ratio and Multi-Wavelength Williamson Pyrometers offer a single-wavelength (SWL) mode of operation.The following notes pertain to commonly asked questions associated with this function. SWL mode can be used to compare readings to single-wavelength models and as a troubleshooting tool.

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Williamson Hot Slug Detector (HSD) for Fiberglass Batting

Posted by Jonathan Stronach on Wed, Jun 28, 2017 @ 10:15 AM

Hot Slug Detector:

Hot slugs form when a process upset causes molten glass to fall from the spinner and into the product during the manufacturing of fiberglass batting. Surrounded by insulating material, these hot slugs remain hot, and days later can cause the paper backing and organic binder material to ignite, creating an expensive and inconvenient fire in a warehouse, on a train or in a truck. The Williamson Model HSD identifies the presence of small slugs below the surface of the fiberglass batting during the manufacturing process. Sensitivity is greatest when mounted after the fluffing blower and before the curing oven. 

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The Williamson model HSD combines three innovative Williamson technologies to produce the most viable and reliable hot slug detector.

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Topics: wavelength, pyrometer, application note

How to Ensure Valid Measurement Conditions Using ESP Filtering

Posted by Kam Olaogun on Wed, Jun 21, 2017 @ 10:50 AM

Williamson Two-Color (TC), Dual-Wavelength (DW) and Multi-Wavelength (MW) pyrometers include a series of advanced signal conditioning functions collectively known as ESP Filtering. This advanced signal conditioning feature allows these Williamson pyrometers to recognize valid measurement conditions and to make an active measure of temperature only when these valid measurement conditions exist. This advanced signal conditioning feature is patented by Williamson Corporation and is available only with Williamson pyrometers.

 

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Topics: troubleshooting, signal conditioning, valid measurement, ratio, dual wavelength, configure esp, interference, esp filtering, signal dilution, signal strength

Dual-Wavelength Measured Parameters: How each works and when to use it

Posted by Jonathan Stronach on Thu, Jun 15, 2017 @ 01:30 PM

 Williamson Dual-Wavelength Output Descriptions and Functionality:

The Williamson Dual-Wavelength (DW) pyrometer includes a series of output parameters that can be used to confirm the proper operation and accuracy of the sensor. These outputs can be viewed as a display option and can also be configured as an output in the Configure I/O submenu. Measured parameters include filtered temp, unfiltered temp, signal strength, signal dilution, ambient temp, and single-wavelength temp. For each output we can select a parameter, range, and scale. Below we have included more information on each parameter regarding what it does and when it is used.

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Topics: pyrometer

How to Select a Focal Distance

Posted by Kam Olaogun on Thu, May 25, 2017 @ 03:24 PM

When the field-of-view (FOV) is filled by a uniformly-heated target, all Williamson pyrometers are distance-independent (beyond 6 inches for traditional style models) because they are fixed-focus. Pyrometers with an adjustable focus, as offered by others, are accurate only within the focal plane. Adjustable focus in some ways is preferred, but they are also easier to misuse because they are not appropriate for a target that moves significantly and are inaccurate when out of focus. Williamson prefers the fixed-focus approach because it is accurate at all distances.

What is FOV?

FOV/Optics Diagram

The field-of-view (FOV) of a pyrometer determines its area of measurement or spot size in relation to its target. This can be further described as the ratio between the pyrometer’s optical resolution and its focal distance. For example a pyrometer with a focal distance of 40 inches and an optical resolution of 100:1 or D/100 would render a spot size with a 0.4 inch diameter from a 100 inch distance or FOV = 0.4in@40in.

The temperature value measured is unchanged as the distance between the pyrometer and the measured target changes, regardless of the focal distance, as long as the field-of-view is filled by a uniformly-heated target.

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Topics: Field of VIew, Optics, Focal Distance

Application Note: Aluminum Hot Rolling Mill - Coiler

Posted by Thomas Huff on Thu, Apr 27, 2017 @ 08:51 AM

This is part 4 of the 4-part Aluminum Hot Rolling Mill application note series - we hope you enjoyed the complete series! Previous parts can be found in our blog feed.

Application Overview:

The temperature at the coiler is an important process parameter.  If the temperature is too hot, then the metal may soften and stick.  If the temperature is too cool, then the material may become too hard and crack.  Hand-held thermocouple probes are notoriously inaccurate and are prone to misuse and interpretation. 


Williamson Wavelength Advantage:Aluminum Coiler.jpg

The multi-wavelength pyrometer produces a much more repeatable and accurate temperature value than the traditional thermocouple.  The pyrometer can be used to measure the temperature of the strip as it enters the coiler and/or measure the side of the coil while it is being wound or after it has been removed from the coiler.


Pyrometer Benefits:

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Topics: aluminum, hot rolling, application note

Application Note: Aluminum Hot Rolling Mill - Finishing Mill

Posted by Thomas Huff on Wed, Apr 26, 2017 @ 08:51 AM

This is part 3 of the 4-part Aluminum Hot Rolling Mill application note series - be sure to check out the rest of the series!

Application Overview:

Tight control of finishing temperature assures the desired mechanical properties and a blemish-free surface.  The low and highly variable non-greybody emissivity character associated with this aluminum process dictates the use of multi-wavelength infrared pyrometers.


Williamson Wavelength Advantage:Aluminum Finishing Mill.jpg

The traditional multi-wavelength (MW) technology works well at the finishing mill where the process is highly repeatable. While the temperature may vary from alloy to alloy, this variation is repeatable. For exceptional accuracy and repeatability across alloys, the MWx technology is required.


Pyrometer Benefits:

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Topics: aluminum, hot rolling, application note

Application Note: Aluminum Hot Rolling Mill - Roughing/Reversing Mill

Posted by Thomas Huff on Tue, Apr 25, 2017 @ 08:51 AM

This is part 2 of the 4-part Aluminum Hot Rolling Mill application note series - be sure to check out the rest of the series!

Application Overview:

At the reversing mill, rolling speed, roll bite and coolant flow may be optimized only with a precise real-time knowledge of metal temperature.  The low and highly variable non-greybody emissivity character associated with this complex aluminum process dictates the use of the most sophisticated multi-wavelength infrared pyrometers as the material converts from a coarse ingot to a smooth strip. 

Williamson Wavelength Advantage:Aluminum Reversing Mill.jpg

The Williamson model MWx, designed specifically for the demanding aluminum hot reversing rolling mill application, uses the most advanced Multi-Wavelength Dynamic ESP Technology available for unequalled accuracy under all operating conditions.

Pyrometer Benefits:

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Topics: aluminum, hot rolling, application note

Application Note: Aluminum Hot Rolling Mill - Ingot Measurement

Posted by Thomas Huff on Mon, Apr 24, 2017 @ 08:51 AM

This is part 1 of a 4-part application note that covers the Aluminum Hot Rolling Mill  - stay tuned for more posts.

Application Overview:

Before heading to the rolling stands, a large ingot of aluminum is heated in a furnace for hours to days. Ingots need to be heated for this long of a time so they are completely heated through to the core so that the ingot can be rolled out into a longer strip without being reheated.


Williamson Wavelength Advantage:Aluminum Ingot.jpg

The ingot is soaked for such a long time to assure uniform temperature prior to rolling, and the soaking time is often extended due to process down time. These extended soaking times often alter the emissive character of the aluminum even when the surface texture is reasonably consistent, and this is the primary reason why the Dynamic ESP Technology associated with the MWx pyrometer is required.



Pyrometer Benefits:

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Topics: aluminum, hot rolling, application note

The 3 Most Common SRU Temperature Measurement Issues and How to Solve Them

Posted by Thomas Huff on Sat, Apr 1, 2017 @ 03:23 PM

When natural gas and crude oil is extracted from the ground it contains some percentage of sulfur.  Gas or oil with a high level of sulfur is said to be sour.  Gas or oil with a low level of sulfur is said to be sweet.  This sulfur is removed from the gas stream by a chemical reaction.  After this process, the sulfur is removed from the gas or oil and is instead contained in amine gas and sour water gas.  The sulfur is then removed from the amine gas and sour water gas in a thermal reactor called an SRU (Sulfur Reactor Unit).  This process is known as the Claus process. The Claus reaction that removes these gasses from the process stream is exothermal, meaning that it creates heat once the process has begun.  As a result, there are several reasons to monitor the temperature of the thermal reaction.

sru_thermal_reactor2.jpgThe thermal reaction is more efficient when run at higher temperatures, and the gas stream may be run through more quickly; therefore, there is tremendous incentive to run the process hot.  Many plants inject oxygen in an effort to raise operating temperatures and to increase process capacity.  However, the refractory walls of the vessel degrade at excessive temperatures, making it essential that the process temperature be closely monitored to balance the need to be efficient at extracting the sulfur while at the same time extending the life of the refractory.  These gasses are highly toxic, and the safe operation of the process is highly critical.

So while temperature is a critical process control parameter in the sulfur recovery process, there can be a number of complications when trying to get an accurate measurement. There are two generally accepted methods of measuring temperature inside of a Claus reactor - thermocouples and infrared pyrometers. This article gives a very comprehensive overview of the benefits and drawbacks of each measurement technique. However,  the following are the most common issues and difficulties associated with the SRU temperature measurement and how to address them.

 1. Constant replacement of thermocouples

One of the most common ways to measure the temperature inside the furnace is with a contact thermocouple device.  However, the inside of the reactor is a hot, nasty, and corrosive environment and thermocouples will often fail and need to be replaced. Thermocouples tend to be troublesome because of their unreliability and require a lot of maintenance work to replace them. It can be difficult to consistently run a process to the same temperature off of thermocouples alone and another means of measurement is typically required. Not to mention, that the constant replacement of these thermocouple devices can be expensive over time.

Solution: Non-contact temperature devices are often used instead or in addition to thermocouple measurements. Non-contact measurement

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Topics: Petrochemical