AP Corp. Selected Druck New England Representative

AP Corp. is delighted to announce that they are now the New England Sales and  Engineering Representative for Druck piezo-resistive pressure sensors and test/calibration instruments.

Druck, a Baker Hughes business, manufactures the high-reliability piezo-resistive pressure sensors and test and calibration instruments known for performing in the most challenging environments. Their products provide customers with the highest performance, stability, quality, accuracy, and quickest response in any environment.

Druck's product line includes pressure sensors,  OEM custom sensors, PACE Pressure Controllers, handheld process calibrators, pressure indicators, test tool instrumentation, and  4Sight2 Calibration Management Software.

The addition of Druck extends AP's offering of high quality, best-in-class, engineered sensor solutions. AP Corp's application expertise and long-standing customer relationships in New England are vital to providing Druck with accelerated sales growth in this territory.

For more information, contact:

AP Corp.
One Tara Boulevard
Suite 200
Nashua, NH 03062
www.a-pcorp.com
508-351-6200 (office)

Distance Measurement for Reflecting Surfaces with Universal Laser Sensor

Plastics, mirrored glass, or metals have highly reflective surfaces and require special laser sensors to measure displacement and distance. Displacement and distance measurements on strongly reflecting surfaces challenge conventional, diffuse reflection laser sensors. 

Laser sensors such as the Micro-Epsilon optoNCDT 1750DR provide a real-time surface compensation feature that controls exposure time that produces stable signals. This type of laser sensor operates on the principle of direct reflection, aligned so that the angle of incidence is equal to the angle of reflection. Proprietary algorithms compensate for the back-scattered, high-intensity light—all of this in a compact design, including an integrated controller (no external control unit is required).

Mounting and wiring are easy. A mounting template enables the user to align the sensor correctly. The laser class 1 rating on which the optoNCDT 1750DR operates is another advantage. Additional safety precautions are not necessary since the emitted laser power does not exceed 390 µW. Users have the choice of an intuitive web interface which can operate the laser sensor from a browser.

For more information in New England, contact AP Corp.

AP Corp.

https://a-pcorp.com

508-351-6200

Do You Have a Production Part Heating Challenge? Get Free Assistance from The LAB

Ambrell's Applications Laboratory, known in the industry as THE LAB, will solve your most challenging heating applications. They will provide recommendations for precision induction heating solutions for parts of every size, shape, and material composition. 

THE LAB will apply their state-of-art testing facility, fully equipped with Ambrell induction heating systems and hundreds of proven coils. You can also interface with their engineers and see first-hand how they design prototype coils and develop innovative, practical solutions to maximize your heating process's efficiency. 

The process is easy. Just follow these three steps:

1. Send THE LAB your parts and process requirements.
2. Their engineers will analyze your process and heat your parts to develop the right solution for your specific application.
3. You will receive your parts back for inspection, as well as a video of the heating process and a laboratory report with a system recommendation.

You have the option to observe testing through Ambrell's Remote Lab Service from the convenience of your office.

If you have old systems that need upgrading, why not find out if using a smaller, more efficient Ambrell induction heating system is the right solution for your process? There are measurable savings in less downtime, higher production throughput, improved energy efficiency, and more.

To learn more in New England and Upstate New York, contact AP Corp. Call them at 508-351-6200 or visit their website at https://a-pcorp.com.

Dynisco Cloud Connect™

With the new Dynisco Cloud Connect™ through Microsoft® Azure – you get a single cloud solution that aggregates all your device(s) data into one place that is secure, reliable, easy to share, with 24/7 support.

The Dynisco Cloud Connect can be used for one product or entire global production lines –whether across the street or across the globe giving you easy access to manage data across the cloud, no matter where it lives. This solution is easily expandable and is even compatible with multiple brands and equipment types, from sensors to melt flow indexers to rheometers. With Dynisco Cloud Connect, you can compare and correlate data between facilities and be able to monitor and adjust parameters in real-time, from a mobile device anywhere in the world, whether working in the field, on the production floor, or in the office. 

For more information about Dynisco products in New England and Upstate New York, contact AP Corp. Call them at (508) 351-6200 or visit their website at https://a-pcorp.com.

Which Melt Pressure Sensor Is Good for My Application?

So how do I choose the right melt pressure sensor for my application? 

A sensor is defined through the following specifications:

• Pressure Range
• Process connection
• Electrical output and connection
• Capillary configuration (rigid/flexible)

There are more variables come into play, but let's focus on these four since they are the most critical.

Melt Pressure Sensor Pressure Range

The pressure inside a plastics processing machine can usually be estimated well enough to determine a sensor's good pressure range. The typical working pressure should be within 20%-80% of the sensor's pressure range to balance accuracy and lifetime.

Melt Pressure Sensor Process Connection

For threaded connections in plastics processing, a standard has developed over time, which is the ½"-20UNF thread with a conical sealing face. There might be situations where different thread sizes or a flange connection is required. There are numerous options available from manufacturers, such as Dynisco, to satisfy customer needs regarding the process connection.

Melt Pressure Sensor Electrical Output

A pressure sensor is an electro-mechanical device that converts a mechanical effect (pressure deflects a thin piece of metal) into an electrical signal through a strain gauge. The strain gauge changes its resistance by following the deflection of the metal piece. In the simplest case, the strain gauge signal can be used directly to feed a read-out device to display the pressure.  In order to accommodate industry-standard equipment, such as process control equipment, manufacturers like Dynisco supplies sensors with different amplified output options such as 4-20mA or 0-10V.

Melt Pressure Sensor Capillary Configuration

A typical pressure sensor has a liquid-filled capillary that connects the process-connection diaphragm (which is deflected by the process pressure) and the measuring diaphragm (where the strain gauge is bonded). This capillary is necessary to create a heat barrier, as the strain gauge cannot withstand the typical process temperatures at plastics processing. Also, the sensor's electronics need to be kept away from heat sources as well as possible. To find a suitable mounting location for the electronics, countless combinations of the rigid stem and flexible connection lengths are available.

Other Considerations in choosing a Melt Pressure Sensor:

• Diaphragm materials
• Diaphragm coatings
• Approvals and certifications

For assistance in selecting or applying any plastics molding equipment, contact AP Corp. by calling (508) 351-6200 or visit their website at https://a-pcorp.com.

EASYHEAT Induction Heaters from Ambrell Corporation

EASYHEAT advanced induction heating systems by Ambrell Corporation provide a flameless, non-contact, reliable, compact solution for heating your parts with a quick, clean source of heat. Available in models from 500 Watt to 10 kW, all are ideal for repeatable, energy-focused heating of your parts.

Flameless, non-contact induction heating minimizes energy waste by focusing energy only on the part and zone to be heated. Select and monitor power levels from the front panel LCD and sealed touch pad. Remote power control is available for employing contact inputs, analog inputs or optional serial data port. Easily control the length of the heating cycle with a built-in programmable digital timer.

Download the Ambrell EASYHEAT® 500 Watt to 10 kW Induction Heater Catalog here.

For more information about Ambrell products in New England, contact AP Corp. Call them at 508-351-6200 or visit their website at https://a-pcorp.com.

New Bench Top Series of Shaker Systems from Sentek Dynamics

The BT Series shakers from Sentek Dynamics are designed for demanding vibration test applications. Typical applications included structural analysis, calibration and testing of smaller assemblies. The BT-100 through BT-400 shakers utilize light weight rare earth magnets in lieu of traditional Alnico magnets. The use of these magnets decreases the total shaker mass to a third of similar size system, making these shakers easy to handle and portable. 

The systems range in size from 100 N (70 lbf) to 1000 N (224 lbf). Systems 400 N (99 lbf) and smaller are permanent magnet shakers and use lightweight rare earth magnets, making these systems easy to handle and portable. There are three versions of the BT Series of shakers: the BT, BT-M and BT-MTH.  

The BT Series is recommended for vibration testing of small assemblies and components. These shakers have armature diameters from 60 mm (2.36 in.) to 120 mm (4.72 in.). The BT-1000 is equipped as standard with Automatic Armature Centering (AAC) and Air-Isolation Feet (AIF).  

The BT-M and BT-MTH Series are our modal shakers lines. BT-M will use standard stingers while the BT-MTH is our through-hole version. On the 100 N and 200 N system the BT-MTH offers over double the displacement. The BT-MTH Series allow you to use piano-wire stingers. The BT-1000-M is ideal for the structural and modal analysis of high-mass structures. The addition of ZPR (electronic zero-point regulation and adjustable suspension stiffness) allows the user to pre-load the structure prior to applying a dynamic load.

The new Sentek Dynamics Bench Top and modal exciters are based upon years of practical experience. These systems all exhibit a high lateral stiffness and high force-to-weight ratio. They are specifically designed to help ensure the best possible performance with minimum setup time. 

Contact AP Corp. regarding any Sentek Dynamics product in New England and Upstate New York. Call us at (508) 351-6200 or visit our website at https://a-pcorp.com.

Micro-Epsilon Laser Profile Scanners: scanCONTROL LLT3000 and 2500

Micro-Epsilon scanCONTROL LLT3000

The scanCONTROL LLT3000 laser profile scanners impress in 2D/3D measurement tasks with high precision and dynamics. With a high resolution sensor matrix and high profile frequency, the scanners are designed for precise profile measurements in dynamic processes.

Micro-Epsilon scanCONTROL 2500

The scanCONTROL 2500 laser scanners are specially designed for industrial measurement tasks. Compact design, versatility and high signal stability result in an excellent price/performance ratio especially for measurement tasks involving large quantities.

Laser profile scanners from Micro-Epsilon are among the highest performing profile sensors with respect to accuracy and measuring rate. Equipped with powerful processors and highly sensitive optical components, these scanners ensure precise profile measurements on nearly any type of surface. While they can be integrated in various environments, the scanners also impress with a compact design which includes an integrated controller.

For more information about Micro-Epsilon products in New England, contact AP Corp. Call them at (508) 351-6200 or visit their website at https://a-pcorp.com.

BLH Nobel KIS Beam Load Cell Technology

The BLH Nobel KIS load cell provides unmatched efficiency, is simple to mount, and is highly accurate, even under complex process forces and extreme environmental conditions. Unlike other load cells, KIS works as defined in real-world applications, not just under laboratory conditions. 

KIS Beam technology integrates SR-4 ® strain gages connected as a full Wheatstone bridge that is temperature-compensated and optimized for precision and reliability. And since all KIS Beams are factory-calibrated, installation and set-up are simple and easy without the need for on-site calibration (unless mechanical obstructions prohibit a vessel being "freestanding"). 

The above four-minute video does an excellent job illustrating how the KIS load cell works and what distinguishes KIS from other load cells

For more information about BLH Nobel products in New England, contact AP Corp. Call them at (508) 351-6200 or visit their website at https://a-pcorp.com.

In-Line Turbidity and Haze Measurement

Photo 1: Equitech's Retro-Reflection Probe

Monitoring turbidity and haze of liquids and sheet is an indicator for product quality. Examples include: polymer extrusion, resins and chemical production. Real-time adjustments of the process parameters are therefore possible through immediate "off-specification" detection.

INTRODUCTION 

Turbidity and haze measurement is a well-accepted technology to check the consistency some production processes. Usually these measurements are performed ‘off-line’.  

The delay between sampling and obtaining the results from the laboratory can be time consuming. A significant disadvantage is that only a single measurement is generated in this time period and the concentration during, before and after the sampling point is unknown.  

With the inline turbidity and haze measurements taking place directly in the process, not only is complete documentation possible, but when variations occur, immediate intervention can take place.

INNOVATION 

The Equispec™ In-line Color Spectrophotometer (ICS) is a high performance instrument designed for use in an industrial pro-cess. Its excellent sensitivity and flexibility make it useful for process applications. The ICS and process probes are designed to be used in high-temperature, high-pressure and corrosive environments. It can be used to analyze  liquids and solids. 

The analyzer supports one or two probes with dedicated lamp compensation channels [all fiber-optic double-beam design]. 

Photo 3: Trend charts of EquiColor Software

TURBIDITY AND HAZE MEASUREMENT 

Equitech’s fiber-optic probes allow for easy access into the process. Equitech offers probes for both turbidity and haze measurements.  This includes insertion/immersion probes (see Photo 1). 

The spectrophotometer is integrated in a NEMA4 box with an industrial computer and touch-screen (see photo 4). The appropriate spectral range is 380-780 nm (resolution 1 nm). The NEMA4 box is made from stainless steel. It is designed and equipped specifically for use in the production environment where the ambient conditions can be dusty, vary in temperature, subject to vibration etc. The box also contains a thermoelectric cooling and heating device to eliminate the influences from ambient temperature by keeping the temperature inside the box at a constant level. 

Photo 2: ICS stainless steel NEMA4 box with touch-screen

INSTALLED APPLICATIONS INCLUDE 

Resin Production, Sheet Production,  Filter Breakthrough, Surfactants 

Turbidity and haze are calculated from the spectral curve,  and displayed as trend charts by the EquiColor™ software (see photo 3). 

For more information, contact AP Corp. Call them at (508) 351-6200 or visit https://a-pcorp.com.

DOWNLOAD THE PDF HERE

What is a Binocular Strain Gauge Load Cell?

Load cells, the heart of weighing systems, are mechanical devices that use strain gages to provide a measurable electrical output which is proportional to the force applied. The electrical output can be either an analog voltage or current output, or a digital on/off output.

Used for tension, compression, and or shear measurement, load cells are packaged and oriented to perform in testing equipment, electronic scales, and monitoring systems. Tension load cells are used for measuring forces that are in-line and "pull apart". Compression load cells are used to measure forces that are in-line and "push together". Shear load cells are used to measure tension or compression forces that are offset (not in-line). When selecting load cells, there are many form factors or packages to choose from to insure their physical size is compatible with space available for the application, such as inside an electronic weighing scale.

The strain gage is a resistive sensor whose resistance changes based upon the applied strain. A strain gage is attached to some structure, and when that structure is deformed (tension, compression, shear), the resistive strands in the strain gage follow the structure deformation, causing an electrical resistance change. This change in resistance is converted to units of strain or stress. 

Strain gages are used in transducers that measure force, pressure, and tension, and are often used providing stress analysis in structures such as airplanes, cars, machines, and bridges. 

When specifying strain gages one must consider the application variables, such as operating temperature, the state of the strain (including gradient, direction, magnitude, and time dependence), and the stability required by the application.

For more information about strain gages and load cells, contact AP Corp. Call them at 508-351-6200 or visit their web site at https://a-pcorp.com.

Load Cells for Weighing Vessels in Hot and Vibration Prone Areas

Most load cells are designed to handle vertical force and cannot discern errors introduced from side loading and/or torque loading. In real world conditions, though, load cells see much more than vertical loading, and unfortunately, can output erroneous values. While they are excellent for static weighing situations, such as scales, load cells typically can’t handle the rigors of process vessel applications.

A case in point is a chemical manufacturer with several, existing three cubic meter batching tanks. It was decided the tanks needed modifications to provide more accurate weighing of the individual ingredients. The existing load cells were experiencing errors due to thermal expansion of the vessel, and the resultant side loads from expansion. Additionally there was a problem with vibration in the plant. A better solution was needed, and whatever the solution would be, the customer made it clear the new weighing system must provide system accuracy in the range of ±0.1%.

An approach to deal mechanically with the thermal cycling while using the same type of load cell was discussed. It involved several mechanical modifications that required significant and costly structural changes.

BLH KIS

Another suggestion was to evaluate a unique load cell design that was particularly tolerant against thermal expansion, vibration, and high lateral forces - the BLH Nobel KIS series.  The KIS load cell offered some obvious advantages over rebuilding the tanks supports and frame, namely time and expense. Beyond the short installation time and easy modification, the KIS also offers excellent reliability and accuracy.

BLH Controller

The customer decided to “take the easy way out” and just replace the old, error-prone load cells with KIS load cells. Installation and start-up was very easy, taking very little time. After installation, the customer was pleasantly surprised by the high accuracy of the new KIS load cells, despite the thermal expansion of the vessel and the inherent vibration.

For more information on BLH Nobel products in New England and Upstate New York contact A-P Corp. Call them at (816) 353-6550 or visit them at https://a-pcorp.com.

Polymer Analysis Using ASTM/ISO Method A Testing and the Dynisco LMI5500 Melt Flow Indexer

One of the specific ways to speed development, quality testing, and analysis of polymers is the ASTM/ISO Method A Test using the Dynisco LMI5500 melt flow indexer. This test is used in order to determine flow characteristics of plastic melts are used in various plastic processing techniques, namely extrusion and injection molding.  

The LMI5500 brings a new level of ease of use with its removable inspection plate, increased access for sample cutting, and improved touch screen. This device provides values on the melt flow rate melt volume rate and melt density of polymers to ensure that the conditions of production are at peak efficiency without sacrificing the quality of your products. Upon test completion results are viewable, and can be sent to the cloud. The information obtained from this test is important for achieving a quality product while maintaining a high level of efficiency in production.

For more infomration on all Dynisco products, contact AP Corp. Visit their web site at https://a-pcorp.com or call (508) 351-6200.

The LMI5500 Series Melt Flow Indexer from Dynisco

Specifically, designed for the thermoplastics resin industry the Dynisco LMI5500 Series Melt Flow Indexer has an array of features and benefits that range from ground-breaking accuracy to a unified software platform between all laboratory and online production equipment.

The LMI5500 provides a new level of simplicity of use with its simple to clean inspection plate, accessibility for sample cutting,  and improved touchscreen display.

Most notable is its own gravitational correction characteristic that takes into consideration gravity according to the units geographic location.

It is capable of delivering a wide range of data for melt flow rate, shear stress, shear rate, apparent viscosity, intrinsic viscosity, melt density, and testing conditions.


FEATURES OF THE DYNISCO LMI5500 SERIES MELT FLOW INDEXER

• Gravitational correction
• New Windows 10 IoT touch screen native interface
• Built in WIFI and ethernet
• HDMI and multiple USB ports
• Direct digital scale USB interface for sample weighing
• Performance meets international standards: ASTM D1238 & D3364, ISO 1133-1, BS2782, DIN 53735, JIS K7210
• Automatic sample cutter for ease and consistency in sample cutting
• Melt Flow Rate to Intrinsic Viscosity correlation for PET
• Nearly unlimited program storage capability 
• Increased access to the die for sample cutting with a strategically placed mirror to easily view the die and cutting area
• Supports multiple languages

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DOWNLOAD THE LMI5500 SERIES MELT FLOW INDEXER DATASHEET FROM THE AP CORP WEB SITE HERE

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For more information about the Dynisco LMI5500 Series Melt Flow Indexer in New England and Upstate New York, contact AP Corporation by calling (508) 351-6200 of visit their web site at https://a-pcorp.com.

Gas Turbine Monitoring with Kistler Pressure and Acceleration Sensors

AP Corporation is pleased to present Gas Turbine Monitoring with Kistler Pressure and Acceleration Sensors

Kistler high-temperature measuring systems allow measuring thermoacoustics phenomena in harsh environments with extreme temperatures up to 700°C.

• Safe and reliable operation of gas turbines thanks to combustion dynamics monitoring.
• Differential charge amplifier designed for high temperature sensors.
• High temperature acceleration sensors measuring vibrations.
• High temperature pressure sensors measuring pressure pulsations.
• Reliable monitoring with durable sensors in harsh environments and up to 700°C / 1300°F.
• Predict, monitor and analyze combustion dynamics.
• Complete differential, ground insulated measuring chains enable early detection of smallest pressure pulsations.

Features of Kistler measuring equipment for combustion dynamics monitoring:

• Resistant to high temperature (700°C / 1300°F)
• Ex certified and interference resistant (EMI, RF)
• PiezoStar sensing element - not pyroelectric and no popcorn effect

For more information, contact AP Corp. for Kistler products in New England. You can reach them by calling (508) 351-6200 or visit https://a-pcorp.com.

Why Plastics Industry Feed Screws are Designed the Way They Are

Download the white paper here.

The selection of the proper screw for a given injection molding or extrusion application can be critical to its success.

Screw geometry — length-to-diameter ratio, profile, channel depth, compression ratio, helix angle and a host of special design features — has everything to do with how well the screw performs in a given application.

There are documented applications where customers have improved production rates or reduced cycle times by 30 or 40% simply by switching to an improved screw design. Similarly, reject rates have been lowered from more than 4-6% to less than 1% by incorporating a custom designed mixing screw.

And experience shows that the amount of color concentrate required to achieve optimum color mix can be typically reduced from 4% (of the total blend) to 2%, just by using an optimized screw design. When considering resin and concentrate costs, payback for an optimized screw and non-return valve design can be almost immediate.

This white paper, published by Glycon Corporation, provides an in-depth look into plastics industry feed screw design.

DOWNLOAD THE WHITE PAPER FROM THIS AP CORP WEB PAGE

In-Line Color Measurement for Recycled Plastic

Photo 1 - Recycled Plastic with Color

INTRODUCTION 

Color measurement is a well-accepted technology to check the quality of the color values in the production process. Usually these measurements are performed "off-line".

The delay between sampling and obtaining the results from the laboratory can be time consuming. A significant disadvantage is that only a single measurement is generated in this time period and the quality of the color during, before and after the sampling point is unknown.

With the in-line color measurements taking place directly in the melt, not only is complete documentation possible, but when color variations occur, immediate intervention can take place.

Photo 2 - Reflection probe in strand pelletizer.

When recycling plastic to convert to new uniform  colored pellets many challenges can take place. Recycled plastic is much more inconsistent than virgin material. Understand-ing this inconsistency will help on your color dosing to provide a more homogeneous final product. With the proper color measurement system you can know the color values of your extrudate in real time. This allows for closing the loop on your color by changing your dosing rates to meet your specifications.

INNOVATIVE NEW TECHNOLOGY

Photo 4 - Stainless Steel NEMA4 box with touch-screen.

Technology from Equitech, a manufacturer of in-line process instrumentation, deploys a probe directly in the molten polymer. Their Reflection Polymer Melt Probe (RPMP, Photo 2) is installed on the exit (adapter) of the extruder by using ½”-20 UNF thread (typically Dynisco®). The RPMP is screwed into position in the adapter between the extruder and the die. The RPMP consists of the threaded body and optical fibers. The sapphire lens on the tip of the probe is the observation window and is very well suited to the harsh conditions in the extruder (temperature, pressure, and friction through flowing material). The self-cleaning function of the sapphire is ensured by the shear force of the material flow. Ideal installation is directly into the melt stream in the adapter.

Off-line measurements are used more effectively by downloading them to the Equitech Inline Color Spectrophotometer. This can be done manually or through OPC communications. By having the laboratory target values displayed on the Equitech system the operator can view trends of L*, a*, b* and Delta E.

This method provides complete documentation of a particular extrusion run. It also matches the known laboratory measurements giving confidence that an extrusion run has maintained specifications throughout its entirety. When color variations occur, notification can take place via digital alarms. Intervention can take place via OPC or analog signals i.e. L* feedback for closed loop color control.

Photo 3 - Trend charts of EquiColor Software

COLOR MEASUREMENT 

Illumination of the polymer through the sapphire window is achieved by 6 circumferentially-positioned glass fibers which convey the light of a xenon flash lamp. The reflection from the illuminated surface is detected by one center-positioned optical fiber. This reflected light is then interpreted by the spectrophotometer. Color values such as L*, a*, b* C*, h are calculated from this spectral curve, and displayed as trend charts, (see Photo 3).

For a continuous process monitoring, 10 to 60 seconds is recommended as the measurement interval. Intervals as fast as 1 to 2 seconds are possible. The calibration of the spectrophotometer is designed specifically for the demands of the production process. Calibration can be done without interruption of the process.

USER BENEFITS

• Real-time information about process stability & quality
• Impact of speed changes on the quality of the extrusion
• Controlled color changes: start phase, end of run  
• Avoid off-specification batches & waste production
• Detection of dosage elevations
• Optimized recipe formulation & process design
• Available feedback loop for L* closed loop control via feeder
• Comprehensive quality audit trail customer documentation

For more information, contact AP Corp. by calling (508) 351-6200 or visiting https://a-pcorp.com.

Reprinted with permission from Equitech International Corporation.

The Three Most Common Types of Temperature Sensors

Various types and styles of temperature sensors (Pyromation).

This post describes the three most popular temperature sensors, how they function, and where they are used.

THERMOCOUPLES

Thermocouple illustration showing base metal designs
with various types of junctions (Pyromation).

Thermocouples are temperature sensing devices that operate on a phenomena called the Seebeck
effect. In the simplest terms, thermocouples produce a micro-voltage between two conductors - joined at each end and made of dissimilar metals - when one junction varies in temperature and the second junction (called the reference junction) is known and maintained at a constant temperature. The corresponding voltage produced at the sensing junction can be measured and directly correlated to the change in the sensing junction's temperature.

Thermocouples are popular and widely used in industrial and commercial temperate systems because they are:

• Cost-effective.
• Provide good accuracy.
• Have a sufficiently linear temperature-to-signal output curve.
• Are available in many different metal alloys for many different temperature ranges.
• Are easily interchangeable.

Thermocouples require no external power source to work and can be used in continuous temperature measurement applications from -185 Deg. Celsius (Type T) up to 1700 Deg. Celsius (Type B).

Thermocouples are commonly found in many industrial processes. Examples are the plastics industry, primary metals, power generation, kilns, industrial boilers, HVAC, gas turbine exhaust systems and and diesel engines. And because they are affordable and easy to produce, thermocouples are also used in many consumer applications, such as residential and commercial cooking and heating equipment.

RTDs

Wire wound RTD
(Image courtesy Wikipedia)

Resistance Temperature Detectors, referred to as RTD’s, are temperature sensing devices that determine temperature based on a relative change in resistance of the sensing element. The sensing element is a wire or etched circuit made from a metal with a well established resistance to temperature curve, most commonly platinum, nickel, or copper.  Platinum, nickel and copper are used because they produce a predictable and stable change in resistance as the temperature changes. Normally the wire is coiled around a bobbin (made of glass or ceramic), and inserted into a protective sheath. Alternatively, RTD's can also be manufactured as a thin-film, etched element with the pure metal deposited on a ceramic base, very similar to the way a printed circuit is made.

RTD’s are popular because:

• They offer considerably higher accuracy and repeatability than thermocouples.
• Can be used up to 600 Deg. Celsius.



Thin-film RTD
(Image courtesy of Wikipedia)

• Can be integrated directly on the part to be monitored.

They are used where accuracy is important, such as in biomedical applications, semiconductor processing and temperature critical industrial applications. They tend to be higher priced than thermocouples because they are made of pure metals, and they do need an excitation voltage from an external source for the device to be read.

THERMISTORS

Another very common temperature sensing device is the thermistor. Thermistors are also a resistance measuring device similar to RTD’s. However, instead of using a pure metal as the resistance element, thermistors employ a very inexpensive polymer or ceramic resistance element. While these materials are very cost-effective, the downside is the resistance-to-temperature output curve. The change in resistance to a corresponding temperature change is very non-linear, and as such, make thermistors' use practical only within a narrow temperature range.

Thermistors are very inexpensive and have a very fast response making them very attractive in applications where a narrow sensing range exists and cost is important. Thermistors also come in two varieties, PTC, or positive temperature coefficient, and NTC, or  negative temperature coefficient. PTC's resistance increases with increasing temperature,  while NTC's resistance decreases with increasing temperature.

Thermistors are used widely in food processing in digital thermostats, and for on-board temperature monitoring of electronics and circuit boards. They are also used widely in many consumer appliances.

For more information on any temperature sensing application, contact AP Corp and discuss your requirement with one of their experienced application experts. They can be reached at (508) 351-6200 or visit them at https://a-pcorp.com.

Dynisco Online Viscosity Measurement

From the Dynisco presentation "From lab to production, providing a window into the process."

Get maximize extrusion efficiency with Dynisco Online Rheological Testing.

Dynisco online rheometers provide a "window into your process" with the ability to continuously measure critical parameters form melt flow ratio to intrinsic / relative / melt viscosity and from constant shear rate to shear sweep.

The video above introduces the Dynisco ViscoSensor, CMR IV, and FCR and presents the viewer a cost justification for their use. You can also download the presentation from the AP Corp. website here.

For more information in New England and Upstate New York, contact AP Corp. by calling (508) 351-6200 or by visiting https://a-pcorp.com.

What are Plastics Industry Feed Screws and How Are They Made?

Feed screw maintenance.

Plastics industry feed screws, or feed screw augers, are mechanisms that use rotating helical screw blades to move plastics pellets through the barrel of molding and extrusion equipment. The feed screw transports the plastic as it changes phase from solid to viscous liquid through friction, shear, and conductive heat transfer. 

A typical feed screw has three zones. Plastic pellets enters the screw feed section where the pellets are compacted and conveyed. Next is the transition (or compression) section, where the plastic is compressed, conveyed, and melted.  Finally, the liquid plastic moves to the metering section where it is precisely controlled at optimum temperature and viscosity.

For more information about feed screws, or any part of the injection molding process, contact:

AP Corp.

https://a-pcorp.com

508-351-6200

Diagram of injection molding process.