Wednesday, August 23, 2017

I/P and E/P Transducers

variants of I/P and E/P electronic to pneumatic transducers
I/P and E/P transducers deliver a pneumatic output
proportional to an electronic input signal.
Image courtesy Rotork Instruments - Fairchild
Converting from one signal type to another is a common challenge in process control. When the application calls for conversion from an electrical signal, current or voltage, to a pneumatic signal (pressure), this calls for an I/P or E/P transducer.

I/P and E/P transducers are electro pneumatic devices that convert current or voltage input signals to a linearly proportional output pressure. These transducers are available in a wide array of configurations to accommodate almost any industrial setting or application.

The transducers pictured use, in the pilot stage, electronic closed loop feedback and a piezoceramic actuator flapper nozzle system, controlling the signal pressure of an integral pneumatic volume booster. A control diaphragm and main valve on the volume booster section controls the flow of air at the output in response to the pressure received from the pilot stage. The output pressure of the volume booster is feed into an electronic closed loop feedback arrangement to deliver accurate pressure control.

Applying the transducer is a straight forward operation, involving matching the device input and output signal capabilities with those of the application. More detail is provided in the document included below.

Share your process measurement and control challenges with instrumentation specialists, combining your process expertise with their product knowledge to produce effective solutions.


Tuesday, August 15, 2017

Cloth Heating Jackets

cloth heat jacket installed on valve
Cloth heat jacket insulates and heats regulator valve
with included control module.
Image courtesy of BriskHeat

Industrial heating applications are numerous and varied. Heating requirements can range from freeze protection to precise maintenance of process temperature in piping, equipment, or vessels. Two commonly employed heating sources are electric resistance heaters and plant steam. While each has certain advantages, steam may not always be available or practical. Electric heat offers a number of positive attributes.

  • Ease of design and installation
  • Precise control
  • Uniform heating across surfaces
  • Low maintenance requirement
  • Portability
  • Economical to purchase and install
  • Wide array of shapes, sizes, and configurations
  • Standard and custom products for every application
Cloth heating jackets are one of many electric heater variants. Formed to fit specific valves, fittings, or other items, these reusable heaters are comprised of an exterior of rugged fabric, a layer of thermal insulation, a heating blanket, and an electrical connection point or fitting. Hook and loop fasteners facilitate the unwrapping or opening of the jacket to allow for installation and removal. The surface remains cool to the touch for most applications. Control can be provided by any type of temperature controller, with prewired options available for inclusion with the heating jacket.

More detail is provided in the document included below. Share your process heating requirements with application specialists, combining your own process knowledge and experience with their product application expertise to develop effective solutions.



Tuesday, August 8, 2017

Load Cells for Industrial Applications

One of many styles of load cells
Load cells - One of many styles used throughout
process measurement applications,
Image courtesy of  Minebea-Intec
In industrial application of process measurement and control, principles of the physical sciences are combined with technology and engineering to create devices essential to modern high speed, high accuracy system operation. Years of research, development, and the forward march of humanity’s quest for scientific knowledge and understanding yields packaged devices for process measurement that are easily applied by system designer and operators.

Load cells are the key components applied to weighing component or processed materials in modern industrial operations. Load cells are utilized throughout many industries related to process management, or just simple weighing operations. In application, a load cell can be adapted for measurement of items from the very small to the very large.

In essence, a load cell is a measurement tool which functions as a transducer, predictably converting force into a unit of measurable electrical output. While many types of load cells are available, one popular cell in multiple industries is a strain gauge based cell. Strain gauge cells typically function with an accuracy range between 0.03% and 0.25%. Pneumatically based load cells are ideal for situations requiring intrinsic safety and optimal hygiene. For locations without a power grid, there are even hydraulic load cells, which function without need for a power supply. These different types of load cells follow the same principle of operation: a force acts upon the cell (typically the weight of material or an object) which is then returned as a value. Processing the value yields an indication of weight in engineering units.

For strain gauge cells, deformation is the applied operational principal, where extremely small amounts of deformation, directly related to the stress or strain being applied to the cell, are output as an electrical signal with value proportional to the load applied to the cell. The operating principle allows for development of devices delivering accurate, precise measurements of a wide range of industrial products.

Load cell advantages include their longevity, accuracy, and adaptability to many applications, all of which contribute to their usefulness in so many industries and applications. A common place to find a strain gauge load cell in use is off a causeway on a major highway at a truck weigh station. Through innovation, load cells have been incorporated in an efficient measuring system able to weigh trucks passing through the station, without having each stop. Aircraft can be weighed on platform scales which utilize load cells, and even trains can be weighed by taking advantage of the robust and dependable nature of the transducers.

Thanks to their widespread incorporation and the sequential evolution of technology, load cells are a fantastically useful tool in process measurement and control. Share your process weighing challenges with application experts, combining your own process expertise with their product knowledge to develop an effective solution.