Humidity and Temperature Transmitters for Demanding Humidity Measurement

Vaisala Humidity sensors and transmitters for process measurement and control
HMT330 Series Humidity and Temperature Transmitters
Courtesy Vaisala
Humidity, the amount of water vapor in the atmosphere or a gas, can be an important measurable attribute of an industrial process. Many are aware of the measurement of relative humidity in HVAC applications and its impact on human comfort in occupied spaces, but the measurement of water vapor in air can be a required measuring point in many other processes that pose far greater challenge.

In addition to common wall or duct mounting applications, where the instrument is easily inserted or placed into the environment to be measured, there are applications that call for special adaptations to the instrument or sensing probe.
  • High pressure
  • Vacuum
  • High temperature
  • High humidity
  • Pressurized pipelines
  • Presence of chemical contaminants
Meeting the full range of industrial process control operations requires stable measurements and the choice of multiple configurations and options to customize the instrument to the process demands. Here are some features worth considering.
  • Multiple variants to match the basic process requirement
  • Full 0 to 100% humidity measurement range up to +180°C (+356°F)
  • PT 100 RTD for accurate temperature measurement
  • Pressure tolerance up to 100 bar
  • Superior sensor accuracy and stability
  • Graphic display and keypad for local operation
  • Multilingual user interface
  • Good chemical tolerance
  • Corrosion resistant housing
  • Delivered with multi-point NIST traceable calibration certificate
  • Analog outputs, RS232/485, WLAN/LAN
  • MODBUS protocol support (RTU/TCP)
  • Long term manufacturer warranty
While not all processes may require, or benefit from, the inclusion of all the listed features and capabilities, reviewing what is available and considering which features may provide better operability in your process can be beneficial. I have included a data sheet below that illustrates the HMT330 Series of humidity and temperature transmitters from Vaisala. Share your humidity measurement challenges with a product specialist. Combining your process knowledge with their product application expertise will produce solid solutions.



Magnetic Level Gauges Superior to Glass Level Indicators

Magnetic Level Gauge
Magnetic Level Gauge
(courtesy of Jogler)
Magnetic level gauges isolate of the process inside of a sealed piping column, thus eliminating the possibility of leaking seals and cloudy or broken site glass. Magnetic level gauges (gages) allow for easy cleaning access and a wide variety of mounting styles and process connections. They also provide improved visibility with highly visible flippers.

Magnetic level gauges are designed with a float in a sealed tube, embedded with permanent magnets. As process level changes, the float rises and falls, and the magnets in the float couple with an external indicator. The indicator is completely isolated from the process.

The following video provides a brief overview of Jogler level products. Jogger is a Baton Rouge, Louisiana manufacturer of high quality magnetic level gauges, magnetostrictive transmitters, direct-reading level gauges with armored shield, sight flow indicators, specific gravity analyzers, point level switches and other accessories. Jogler products are custom designed to meet customer specifications and manufactured to applicable ASME B31.1 and B31.3 code requirements to ensure reliable operation and maintenance free design.

Video on Bubble Noise in Dissolved Oxygen Signals

stainless steel fermentation tanks in brewery
Modern Brewery
Process engineers and operators continually seek faster and more accurate means of measuring variables within the process. Greater currency and accuracy of information can lead to better control and decision making, with a positive impact on efficiency and safety.

Measurement of specific dissolved gases within a liquid plays an important part in many processes in the biopharmaceutical, food, and beverage industries. Mettler Toledo, through their Ingold brand, has developed a solution to a common problem associated with measuring dissolved oxygen. Provided below is a video which illustrates how bubbles can impact the sensor reading, plus Mettler Toledo's solution to the problem. There is also an application note provided below the video which further explains the problem and solution.

Share your process measurement and control challenges with product specialists. Combine your process experience with their product application expertise to devise the best solutions.




Pharmaceutical Industry Case Study: Extend Bioreactor Useful Life With Automation Refurbishing

bioreactor automation control system for pharmaceutical processing
Fermenter/Bioreactor Control System
Courtesy ILS Automation
Bioreactors can have their useful working life extended, even made more productive, through the replacement of the automation and control system. Modern measurement and control gear can provide utility that may not have been available at the time of original manufacture. With vessel, support structure, and piping in good condition, a system may be a viable candidate for refurbishing to bring about upgraded performance or avoid the purchase of an entire new system. ILS Automation is a specialist in the realm of refurbishing bioreactor systems.

The company has several drop-in replacement control units for smaller bioreactors, and also provides turn-key solutions for larger systems. The ILS expertise also extends into other industrial process control and automation fields in the biotechnology, chemical, oil and gas industries.

A bioreactor control system update case study is included below. More product, service, and capabilities information is available from Alliance Technical Sales.


Magnetostrictive Level Transmitter for Process Measurement & Control

Magnetostrictive liquid level transmitter for industrial process measurement and control
Magnetostrictive
Liquid Level
Transmitter
(Jogler)
Physical properties of certain materials can be applied using ingenuity and creativity to create useful appliances. Magnetostriction, a physical property of ferromagnetic materials, produces a change in shape or dimension in the subject material when it is magnetized. This basic principle is integrated into a liquid level transmitter by extending a sensing wire along the interior length of a tube immersed in a process tank or other vessel containing the liquid to be measured. The transmitter pulses the sensing wire with an electrical current, creating an electromagnetic field. A magnetic float, travelling along the outside of the sensing tube, rises and falls as the liquid level in the tank changes. As the float moves along the length of the sensing tube, it creates a torsional stress in the sensing wire, starting at the position of the float, which matches the level of liquid in the tank. A sensing element converts the torsional stress in the wire to an electrical pulse. The transmitter measures the time differential between the initial pulse it sent down the sensor wire and the pulse resulting from the torsional stress and then calculates the position of the float and the liquid level.

These devices are very accurate and operate on a standard 2-wire loop. There are numerous options and variants that allow configuration for each application.

More information is included in the data sheet below. Your best source for current product and application information is a product specialist. Combining your process knowledge with their application expertise will produce the best outcomes.



Temperature Sensors for Process Measurement - Thermocouple, RTD, Thermistor

straight tube thermocouple, RTD or thermistor for temperature measurement
Simple RTD, thermocouple, thermistor
straight tube assembly
Courtesy Smart Sensors, Inc.
This post explains the basic operation of the three most common temperature sensing elements - thermocouples, RTD's and thermistors.

A thermocouple is a temperature sensor producing a micro-voltage from a phenomena called the Seebeck Effect. In simple terms, when the junction of two different (dissimilar) metals varies in temperature from a second junction (called the reference junction), a voltage is produced. When the reference junction temperature is known and constant, the voltage produced by the sensing junction can be measured and a corresponding temperature derived.

Thermocouples are widely used for industrial and commercial temperate control because they are inexpensive, exhibit appropriate accuracy for many applications, have a fairly linear temperature-to-voltage output curve, come in many “types” (different metal alloys) for many different temperature ranges, and are easily interchangeable. They require no external power to work and can be used in continuous temperature measurement applications from -185 Deg. Celsius (Type T) up to 1700 Deg. Celsius (Type B).

Common application for thermocouples are industrial processes, the plastics industry, kilns, boilers, steel making, power generation, gas turbine exhaust and diesel engines, They also have many consumer uses such as temperature sensors in thermostats and flame sensors, and for consumer cooking and heating equipment.
wire wound RTD
Coil wound RTD element
(image courtesy of Wikipedia)

RTD’s (resistance temperature detectors), are temperature sensors that produce a measurable change in resistance as the temperature of the RTD sensing element changes. They are normally designed as a fine wire coiled around a bobbin (made of glass or ceramic), and inserted into a protective sheath. They can also be manufactured as a thin-film element with the pure metal deposited on a ceramic base much like a circuit board.

thin film rtd
Thin-film RTD element
(image courtesy of Wikipedia)
The RTD wire is usually a pure metal such as platinum, nickel or copper because these metals have a predictable change in resistance as their temperature changes. RTDs offer considerably higher accuracy and repeatability than thermocouples and can be used up to 600 Deg. Celsius. They are most often used in biomedical applications, semiconductor processing and industrial applications where higher accuracy is important. Because they are made of pure metals, they tend to more costly than thermocouples. RTDs do need to be supplied an excitation voltage from the control circuitry.

The third most common temperature sensor is the thermistor. Thermistors work in a similar fashion to RTDs, in that they are a resistance based device, but instead of using pure metal, thermistors use a very inexpensive polymer or ceramic material as the element. The practical application difference between thermistors and RTD’s is the resistance response curve of thermistors. It is very non-linear, making thermistors useful over a narrower temperature range than RTDs.

thermistor
Thermistor bead with wires
(image courtesy of Wikipedia)
Thermistors however are very inexpensive and have a very fast response. They also come in two varieties, positive temperature coefficient (PTC - resistance increases with increasing temperature), and negative temperature coefficient (NTC - resistance decreases with increasing temperature). Thermistors are used widely in monitoring temperature of circuit boards, digital thermostats, food processing, and consumer appliances.

Temperature sensors are available in an almost infinite number of assemblies and configurations to accommodate every conceivable application. Share your application with a product specialist and take advantage of their application knowledge and experience.

New Generation of Mettler Toledo M300 pH/ORP, Dissolved Oxygen, Conductivity, & Ozone Transmitters

M300 Process
M300 Process Transmitter
METTLER TOLEDO Process Analytics has released a second generation of M300 transmitters for pH, Conductivity, Oxygen, and Ozone sensors in April 2016. This release simplifies both the Process and Water M300 portfolio through the reduction of 26 unique model numbers down to ten. This is possible through new mix-mode functionality providing compatibility of both analog and digital Intelligent Sensors Management (ISM®) sensors to the latest generation. New M300 transmitters are easily identified by their high-contrast touchscreen display and advanced ISM diagnostic capabilities providing significant advantages to the product line.

The multi-parameter M300Process transmitter line for pH/ORP, dissolved oxygen, conductivity and ozone measurements offers exceptional measurement performance as well as excellent user ergonomics.

The high contrast black and white touchscreen together with the harmonized menu structure for all parameters, facilitates navigation and ensures easy and user friendly operation.

On-line diagnostics information allows you to schedule sensor maintenance or replacement. The clearly visible diagnostic information lets you know when it’s time to do maintenance or calibration of sensors equipped with Intelligent Sensor Management (ISM) technology.

The integrated USB interface allows you to use it for data logging or to store the configuration on a USB stick.

Second generation M300 transmitters are direct replacements to first generation products.



For more information, contact:
Alliance Technical Sales
312 Park Avenue Unit 145
Clarendon Hills, 60514-0145
Phone: 630-321-9646
Fax: 630-321-9647
www.alliancets.com