Showing posts with label Wika. Show all posts
Showing posts with label Wika. Show all posts

Friday, August 31, 2018

WIKA Phases Out PSD-30 and PSD-31 Pressure Switches, Replaced with PSD-4 Pressure Switch

PSD-4 Pressure Switch
The WIKA PSD-30 and PSD-31 pressure switches are currently being phased out, to be replaced with the newly updated PSD-4 pressure switch.

The model PSD-4 pressure switch represents the extensive development of the  PSD-30 pressure switch.  A high accuracy of 0.5 %, freely configurable output signals (PNP/NPN, 4-20 mA / 0-10 V), the 5:1 scalability of the analog output, in addition to outstanding self-diagnostics, make the PSD-4 an excellent automation solution for industrial machines, hydraulic systems, and pneumatic systems applications.

While the PSD-4 offers new features and functionality, pricing is comparable to that of the PSD-30 and PSD-31.  This new pressure transmitter offers customizable features, such as allowing the user to select the switch type and output signal, while offering a 5:1 turndown ratio.  Additionally, this transmitter is an economical solution for applications requiring local display with an analog output signal.  The PSD-4 provides an upgrade in quality and customizability without negatively affecting budgets.

During development of the WIKA switch family a high value was placed on a robust design and the selection of appropriate materials suited to machine-building applications.  For this reason the case and the threaded connection of the electrical connector are made from stainless steel.

For more information, contact M.S. Jacobs by visiting https://msjacobs.com or by calling 800-348-0089.

Friday, November 10, 2017

Differential Pressure Gauge for Level Indication on Liquefied Gas Tanks

differential pressure gauge for cryo tank level indication
A differential pressure gauge can be used to
indicate liquid level in tanks of liquefied gas
Image courtesy Wika
Wika, globally recognized leader and innovator in the design and manufacture of pressure and temperature gauges, provides an enormous number of variants and models of its basic pressure gauge. Many of the gauges are targeted at specific applications, and incorporate a range of design and operational features to accommodate the needs of those applications.

The Cryo Gauge is designed to provide indication of the level of liquid in liquefied gas tanks, but can also serve in some other related applications. For cryo tank applications, several available measuring cells provide operating ranges that cover the most commonly used tank sizes and gas types. An optional manifold with a separate pressure gauge provides connectivity and an indication of working pressure, all in one compact station. Options for analog output, level switches, and remote data transfer are part of the flexible configuration.

More detail on the Cryo Gauge is provided in the datasheet included below. Whatever the application, share your pressure measurement challenges with process measurement experts, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.



Wednesday, September 7, 2016

RTD or Thermocouple for Your Temperature Measurement Application?

RTD or thermocouple temperature sensor assembly
Temperature Sensor Assembly
Wika
Proper temperature sensor selection is key to getting useful and accurate data for maintaining control of a process. There are two main types of temperature sensors employed for industrial applications, thermocouple and resistance temperature detector (RTD). Each has its own set of features that might make it an advantageous choice for a particular application.

Thermocouples consist of a junction formed with dissimilar conductors. The contact point of the conductors generates a small voltage that is related to the temperature of the junction. There are a number of metals used for the conductors, with different combinations used to produce an array of temperature ranges and accuracy. A defining characteristic of thermocouples is the need to use extension wire of the same type as the junction wires, in order to assure proper function and accuracy.
Here are some generalized thermocouple characteristics.

  • Various conductor combinations can provide a wide range of operable temperatures (-200°C to +2300°C).
  • Sensor accuracy can deteriorate over time.
  • Sensors are comparatively less expensive than RTD.
  • Stability of sensor output is not as good as RTD.
  • Sensor response is fast due to low mass.
  • Assemblies are generally rugged and not prone to damage from vibration and moderate mechanical shock.
  • Sensor tip is the measuring point.
  • Reference junction is required for correct measurement.
  • No external power is required.
  • Matching extension wire is needed.
  • Sensor design allows for small diameter assemblies.
RTD sensors are comprised of very fine wire from a range of specialty types, coiled within a protective probe. Temperature measurement is accomplished by measuring the resistance in the coil. The resistance will correspond to a known temperature. Some generalized RTD attributes:
  • Sensor provides good measurement accuracy, superior to thermocouple.
  • Operating temperature range (-200° to +850°C) is less than that of thermocouple.
  • Sensor exhibits long term stability.
  • Response to process change can be slow.
  • Excitation current source is required for operation.
  • Copper extension wire can be used to connect sensor to instruments.
  • Sensors can exhibit a degree of self-heating error.
  • Resistance coil makes assemblies less rugged than thermocouples.
  • Cost is comparatively higher
Each industrial process control application will present its own set of challenges regarding vibration, temperature range, required response time, accuracy, and more. Share your process temperature measurement requirements and challenges with a process control instrumentation specialist, combining your process knowledge with their product application expertise to develop the most effective solution.


Wednesday, February 10, 2016

Improved Gauge Visibility With New Product Feature From Wika

luminous glow in the dark instrument gauge
Wika Instrument gauges have optional high visibility feature.
Wika Instrument, a world class manufacturer of temperature, pressure, level, and flow instrumentation for the industrial process control field, has introduced a product innovation that allows operators to observe gauge readings in low light conditions. The product enhancement comes in two forms, called InsightTM and Insight GlowTM. I have inserted the manufacturer's published description of both options below, along with a video that demonstrates the Insight GlowTM in low light conditions.

More detailed information, along with application assistance and product configuration, is available from an experienced Wika distributor. Use your process expertise and their product application knowledge to achieve the best solutions to instrumentation challenges.

From the company:
InSightTM
The InSightTMoption includes a retro-reflective material affixed to the dial face. At daylight, the fluorescent color absorbs non visual UV light reflecting additional light and making the gauge even more visible. At low light, the pattern of the retro-reflective material also makes the dial more visible to stand out among other regular gauges.
This easy-to-view option comes in three colors: white, fluorescent yellow, and fluorescent orange. It is currently available on industrial and process type gauges (SS wetted parts) and bimetal thermometers for both dry and liquid-filled case options, in sizes from 2 ½” to 6” in diameter.
InSight GlowTM
The InSight GlowTM option uses a retro-reflective, photo-luminescent dial design that illuminates the entire front of the instrument dial for an extended amount of time when exposed to a light source for as little as 10 seconds. The dial appears bright white in darkness, fog, smoke, and fire.
Like the InSightTM option, the Glow is also available on industrial and process type gauges (SS wetted parts) and bimetal thermometers for both dry and liquid-filled case options, in sizes from 2 ½” to 6” in diameter.
Additional Factors to Consider
WIKA has developed additional options to enhance the readability of gauges. For example, a magnification window enables instruments to be read from a distance. An anti-glare window eliminates unwanted reflection of sunlight or bright indoor lighting.
For any gauge, dial size is also a key specification that can aid in readability. Accurate information allows you to operate safely and efficiently. Where possible, WIKA recommends a minimum size of four inches in diameter for process gauge dials. This enables them to be easily read from three to six feet away.

Monday, December 21, 2015

Process Measurement and Control: When To Use a Diaphragm Seal

Industrial diaphragm seal for pressure measurement instrument
Diaphragm seal for pressure measurement device
Courtesy Wika
Process measurement sensors are not indestructible. Not even the most rugged device is fully immune to the chemical nature of process media or the kinetic impact associated with fluid composition and movement. Balancing degrees of protection, usually to increase the useful life of the device, with sensor response and accuracy is a frequent challenge in the process measurement and control field. 

Industrial processes commonly are associated with corrosive or toxic fluids, often at extreme pressure or temperature and containing various levels of solids. Any of these traits can pose substantial risk to process performance and uptime. Operations that process fluids will employ pressure measurement devices to monitor process performance and maintain system safety levels. There are many instances where characteristics of the process and its media are not compatible with pressure measurement devices. Here are some potentially problematic scenarios for pressure measurement instruments: 
  • Corrosive media that will prematurely deteriorate the pressure sensing element. 
  • Viscous or fibrous media, also those that may crystallize or polymerize, posing a risk of clogging channels, tubes, and orifices of pressure measurement devices. 
  • Media temperature that is beyond the rated range for the pressure measurement device has a potential to damage the instrument or cause error in the pressure reading. 
  • A measuring point that is remotely located from where a technician may need to observe the reading. Also conceivable, the pressure measurement device needs to be located away from other potentially damaging environmental conditions. 
  • The process requirements dictate specific hygienic requirements that are cause for the measurement device to be isolated from the medium. 
  • Toxic or otherwise hazardous media that must be contained. 
  • Excursions of system pressure may exceed the acceptable range of the instrument, potentially damaging the device. 
industrial process threaded diaphragm seal
Threaded diaphragm seal
Courtesy Wika
A solution which can provide protection from the items listed above, while still maintaining instrument response and accuracy is a diaphragm seal. Seals are placed between the pressure measurement device and the process media. The space between the diaphragm, which is flexible, and the sensor is filled with a fluid that will hydraulically transfer the pressure condition on the process side of the diaphragm to the sensor. The diaphragm serves as a physical barrier between the potentially damaging media and the instrument. Diaphragm seals are available in a wide variety of configurations to accommodate any media type or connection requirement.

Seal selection involves specifying the connections and form factor to properly mate the diaphragm with the instrument and the process, then selecting the diaphragm material that will be compatible with the media. The best way to achieve a positive solution is to share your requirements with a qualified assembler. They can help select the right diaphragm seal and mate it up with a pressure gauge, providing a complete assembly that is ready to be installed in your process.

Monday, September 7, 2015

Practical Considerations for Thermocouple Selection

Industrial Thermocouples, Fixed Bend Bayonet Type
Industrial Thermocouples, Fixed Bend Bayonet Type
Courtesy Wika
It would be difficult to chart a career course in the industrial process control field without being exposed to thermocouples. They are the ubiquitous basic temperature measuring tools with which all process engineers and operators should be familiar. Knowing how thermocouples work, how to test them, is essential. Sooner or later, though, you may be in charge of selecting a thermocouple for a new application. With no existing part in place for you to copy, what are the selection criteria you should consider for your process?

Thermocouple sensor assemblies are available with almost countless feature combinations that empower vendors to provide a product for every application, but make specifying a complete unit for your application quite a task. Let's wade through some of the options available and see what kind of impact each may have on temperature measurement performance.

  • Thermocouple Type: Thermocouples are created using two dissimilar metals. Various metal combinations produce differing temperature ranges and accuracy. Types have standard metal combinations and are designated with capital letters, such as T, J, and K. Generally, avoid selecting a type that exhibits your anticipated measurements near the extremes for the type. Accuracy varies among thermocouple types, so make sure the accuracy of the selected type will be suitable.
  • NIST Traceability: This may be required for your application. The finished thermocouple assembly is tested and compared to a known standard. The error value between the thermocouple shipped to you and the standard are recorded  and certified. The certified sensor assembly will be specially tagged for reference to the standard.
  • Junction Type: If your sensor will be contained within a tube or sheath, the manner in which the actual sensor junction is arranged is important. The junction can be grounded to the sheath, electrically insulated from the sheath (ungrounded), or protruded from the sheath (exposed). If your process environment may subject the sensor assembly to stray voltages (EMF), it may be wise to stay away from a grounded junction, even though it provides fast response to a change in temperature. Exposed junctions provide very quick response, but are subjected to potential damage or corrosion from surrounding elements. The ungrounded junction provides protection within the enclosing sheath, with a slower response time than either of the other two junction types. When using ungrounded junctions, keep the mass and diameter of the sheath as small as might be practical to avoid overdamping the sensor response.
  • Probe Sheath Material: This applies to assemblies installed in a tube or sheath which houses and protects the sensor junction and may provide some means of mounting. Material selections include a variety of stainless steel types, polymers, and metals with coatings of corrosion resistant material to suit many applications. Make sure the sheath material, including any coatings, will withstand the anticipated temperature exposure range.
  • Probe Configuration: Sheath tube diameter and length can be customized, along with provisions for bends in the tube. Remember that as you increase the mass around the junction, or increase the distance of the junction from the point of measurement, the response time will tend to increase.
  • Wika Industrial Thermocouples, Various Termination Options
    Industrial Thermocouples, Showing Various Termination Options
    Courtesy Wika
  • Fittings and Terminations: There are innumerable possibilities for mounting fittings and wiring terminations. Give consideration to ease of access for service. How will the assembly be replaced if it fails? Are vibration, moisture, or other environmental factors a concern? What type of cable or lead wires would be best suited for the application?
Your options are so numerous, it is advisable to consult a manufacturer's sales engineer for assistance in specifying the right configuration for your application. Their product knowledge and application experience, combined with your understanding of the process requirements, will produce a positive outcome in the selection procedure.