Friday, July 31, 2015

Dynamic Compensation for Static Pressure Effects in Differential Pressure Measurement

Differential Pressure Transmitter
Differential Pressure Transmitter
Courtesy Yokogawa Corp.
Attaining the best available performance and accuracy from any measuring device utilized in an industrial process is always advantageous. The scale of most industrial processes is such that even small inaccuracies in process measurement produce financially tangible impact. Differential pressure measurement, with wide application in the industrial process sphere, can be improved with the addition of a means to compensate for the real world effects of static pressure upon instrument performance. Yokogawa Corporation has developed a means to dynamically compensate for static pressure effects in field measurements. The brief technical presentation below will help you understand how static pressure effects can impact your field measurements, as well as how Yokogawa’s Real-time Dynamic Compensation works to offset its impact. More detailed product and application information is available from your Yokogawa specialist.



Monday, July 20, 2015

Data Acquisition - A Step in the Direction of Process Improvement

Data acquisition, like an equipment acquisition, is the procurement of an asset. Data is an asset. It helps an operator evaluate process or business conditions and make decisions that impact the success of the organization. Let’s define data acquisition as the sampling of signals that represent a measurement of physical conditions and the conversion of those signals into a numeric form that can be processed by a computer. A data acquisition system will generally consist of sensors, transmitters, converters, processors, and other devices which perform specialized functions in gathering measurements and transforming them into a usable form.

Industrial data acquisition equipment
DAQ incorporating data acquisition, process
control, recording, display and networking
in a single compact unit
Courtesy Yokogawa Corp.
Industrial process operators and stakeholders benefit from the collection and analysis of data by enhancing performance of valuable facets of the process or activity. Data acquisition, commonly known as DAQ, is widely employed in high stakes and sophisticated processes where there is a true need to know current conditions. A desire for increased profit drives the need for increased process output and efficiency. A desire to reduce risk of loss drives the need for reduced downtime and improved safety. Today, there are likely many useful applications for data acquisition that are not being tapped to their fullest potential. The modest cost and simplicity of putting a data acquisition system in place, compared to the benefits that can be derived from a useful analysis of the data for your operation or process, makes the installation of a data acquisition system a positive move for even small and unsophisticated operators in today’s market.

What we call DAQ today started in the 1960’s when computers became available to businesses of large scale and deep pockets. By the 1980’s, personal computers employed in the business environment could be outfitted with input cards that enabled the PC to read sensor data. Today, there is an immense array of measurement and data collection devices available, spanning the extremes of price points and technical capability. For a reasonable cost, you can measure and collect performance data on just about anything. You can get an impression of the simplicity, modularity, and compactness of a modern system with a quick review of this product.

Data acquisition has an application anywhere an operator or stakeholder can benefit from knowing what is occurring within the bounds of their process or operation. Here is a partial list of the many physical conditions that can be measured in industrial settings:


Industrial data acquisition equipment
Other examples of industrial data acquisition equipment
Courtesy Yokogawa Corp.
  • Temperature
  • Pressure
  • Flow
  • Force
  • Switch Open or Closed
  • Rotational or Linear Position
  • Light Intensity
  • Voltage
  • Current
  • Images
  • Rotational Speed

Consider your industrial process or operation. Are there things you would like to know about it that you do not? Would you like to increase your insight into the workings of the process, how changes in one condition may impact another? Do you know what operating condition of each component of your process will produce the best outcomes? Is reducing maintenance, or heading off a failure condition before it occurs something you would like to have in your operation? Applying your creativity, ingenuity and technical knowledge, along with the help of a product expert, will help you get the information you need to improve the outcomes from your industrial process or operation.

Friday, July 17, 2015

Miller Energy - Industrial Instrumentation and Process Control Solutions

Miller Energy is a Manufacturer's Representative and Distributor of industrial instrumentation and process control equipment.  Miller is committed to exceeding customers expectations by providing an unparalleled level of customer service and local technical support.

Miller offers the most comprehensive line of measurement, control, and communication solutions in industry today. The products provided by Miller solve challenging applications in the industrial gas, power, refining, chemical / petro-chemical, food & beverage, water/wastewater, and pharmaceutical markets.

Wednesday, July 15, 2015

Guided Wave Radar for Hygienic Applications: Advantages Over Other Technologies

Guider Wave Radar
Guided Wave Radar
for Hygienic
Applications
Operating Principle

Guided wave radar is based upon the principle of TDR (time domain reflectometry). Pulses of electromagnetic energy travel via the waveguide. The pulse is reflected when it contacts a liquid surface and the distance is then calculated.

Guided wave radar transmitters are available with a 304 stainless steel housings designed specifically for use in hygienic applications. This instrument meets the needs and requirements for the wetted and non-wetted materials, process connections and surface finishes of hygienic industries.
Features
  • Low dielectric measurement capability (╬Ár >_ 1.4)
  • Volumetric output
  • Quick connect/disconnect probe coupling
  • Operates in visible vapors and ignores most foams
  • IS, XP, and Non-Incendive approvals
  • Ignores coating buildup
Advantage Over Other Technologies
  • Advantage over Differential / Hydrostatic Pressure Transmitter:  Replaced by Eclipse due to setpoint shifts, blockage, leakage, installation cost & long term calibration / maintenance
  • Advantage over Magnetostrictive: Replaced by Eclipse due to setpoint shifts, turn-down and clean ability & long term calibration / maintenance.
  • Advantage over RF Capacitance: Replaced by Eclipse due to dielectric shifts, coating issues & long term calibration / maintenance.
  • Advantage over Load Cells: Eclipse is more cost effective and long term cost of ownership is lower due to long term calibration / maintenance.
  • Advantage over Ultrasonic: Replaced by Eclipse due to vapors, condensation, temperature restrictions, foaming & turbulence.
  • Advantage over Through Air Radar: Replaced by Eclipse due to performance issues on low dielectric media, short range measurement because of dead band issues in small vessels, measurement issues when using false echo rejection from internal obstructions such as agitators and spray balls, signal attenuation from turbulence, foam, condensation and spray from spray balls used during cleaning or product filling. Through air radar can have issues from variable false echoes generated when spray hits the antenna when vessel is filled from spray balls.
For more information see this Guided Wave Radar bulletin:

Monday, July 13, 2015

Valve Selection: A Look at Ball Valves

industrial ball valves
Industrial Application Ball Valves
In the realm of industrial process control valves, your selections for most applications are vast. Every application will likely have one or more elements become critical and deciding factors for valve selection. That element might be complex and highly technical, being intimately related to physical or dynamic properties few understand. Conversely, the selection may hinge upon something as obvious as what will fit in the space that is provided. Whatever the case, some efficiency can be brought to bear in your selection process by initially deciding which type of valve would best suit the application. This allows you to focus on a much smaller universe of product candidates for your project.

Like most valves, ball valves are characterized by their closure mechanism.  Generally, a ball valve has a spherically shaped fabrication (ball) that is inserted in the fluid flow path. The ball has an opening through its center, often circular in cross section and matching the diameter and shape of the connected pipe. The ball is contained within the body of the valve and rotated around its central axis by torque applied to the stem. The stem, which extends through a seal to the exterior of the valve body, can be manually or automatically controlled via several methods.

During valve operation, the ball is rotated through a ninety degree arc from a fully closed to fully open position. When fully closed, the opening in the ball faces the sidewalls of the valve body and is cut off from the fluid by seals that secure the ball in place and prevent fluid flow around the ball. As the valve stem is rotated toward the open position, the cross sectional area of the opening is increasingly exposed to the fluid flow path until the open area through the ball is aligned with the flow path in the fully open position.

Consider some of these main points and see if a ball valve might be a good selection for your application.

In the plus column:
ball valve in gas pipeline
Large Ball Valve in a Gas Pipeline
  • When closed this valve type provides a tight closure. When open fully,there is very low resistance to flow.
  • Suitable for applications requiring only fully closed or open control.
  • With only 90 degrees of rotational motion from open to closed positions, ball valves can provide rapid response to a change in position requirement or command.
  • Ball valves are comparatively compact, without the space requirement for extending stem movement as required by some other valve types.
  • Ball valves are available in a wide range of construction materials for the body, stem, ball, and seals, making them suitable for a wide range of fluid types and temperatures.
  • Force required to rotate to valve stem is moderate, keeping actuator options high and energy requirements low.
  • A full size port provides for very low pressure drop across the valve when fully open.
  • Requirements for maintenance are generally low. No lubrication required.

In the other column:
  • Ball valves are not well suited for throttling applications. Partially open valves expose the seals to the effects of the flow velocity, with possible premature seal deterioration.
  • A closed valve can trap residual amounts of fluid in the port (the opening through the ball). This fluid will be released to the valve outlet when the valve is opened.
  • Elastomeric materials are often used for the valve seals. Evaluate whether the seal materials are compatible with the fluid characteristics and operating temperature.

There are special adaptations of ball valves which may overcome some of the concerns you have about their application on your project. It is always a good idea to consult with a valve specialist and consider their recommendations for your project.

Monday, July 6, 2015

Valve Selection - When to Choose a Butterfly Valve

Industrial process control valves are available in a staggering array of materials, types, and configurations. An initial step of the selection procedure for a valve application should be choosing the valve type, thus narrowing the selection field to a more manageable level. Valve "types" are generally defined by the closing mechanism of the valve.

butterfly valve
Butterfly Valve
Courtesy Crane CPE
A butterfly valve has a disc that is positioned in the fluid flow path. It rotates around a central axis, the stem, through a 90 degree arc from a position parallel to the flow direction (open) to perpendicular (closed). A variety of materials are used in the valve body construction, and it is common to line the valve with another material to provide special properties related to the process media.

What might make a butterfly valve a beneficial selection over another valve type?

  • The closure arrangement allows for a comparatively small size and weight. This can reduce the cost, space, and support requirements for the valve assembly.
  • Generally low torque requirements for valve operation allow for manual operation, or automation with an array of electric, pneumatic, or hydraulic actuators.
  • Low pressure drop associated with the closure mechanism. The disc in the flow path is generally thin. In the fully open position, the disc presents its narrow edge to the direction of flow.
  • Quarter turn operation allows for fast valve operation from fully closed to fully open.
  • Some throttling capability is provided at partially open positions.
  • Small parts count, low maintenance requirements.
What may be some reasons to consider other valve types?
Butterfly Valve
Courtesy Crane CPE
  • Butterfly valve throttling capability is generally limited to low pressure drop applications
  • Cavitation can be a concern.
  • Some sources mention the possibility of choked flow as a concern under certain conditions.
Butterfly valves, like other valve types, have applications where they outperform. Careful consideration and consultation with a valve expert is a first step toward making a good selection.