Sunday, April 29, 2018

Armored Liquid Level Gauges

Armored Liquid Level Gauge
Armored Liquid Level Gauge
(Jerguson)
Sight glass liquid level gauges are a mainstay of fluid processing operations that store raw materials, intermediate, or final product in tanks and other vessels. Having a direct visual indication of fluid level at the tank enhances safety and provides the all important data point about what is happening inside the tank.

These level gauges are installed on the exterior of the tank, exposed to whatever environmental or operational hazards existing or occurring at the location. Armored level gauges are appropriately named because of their construction. They are designed to resist impact and mechanical stress, as well as a range or environmental conditions.

Armored Liquid Level Gauge
Reflex Gauge
There are generally two versions of armored level gauges, reflex and transparent. The names refer to way in which light is handled by the gauge to reveal the liquid level. One manufacturer of armored level gauges and other level instruments, Clark-Reliance, provides a good description of the two gauge types.

"Jerguson® Reflex Level Gauges are ideal for clean total level indication applications for refining, petrochemical and general use applications. The reflex prisms are molded and polished to provide a crisp black-silver bi-color indication of the fluid level. As light passes into the reflex glass, if there is fluid present, the light continues through the glass and reflects off the back of the level gauge, providing a black color for fluid level regardless of the actual color properties of the process fluid. If fluid is not present, the light is reflected off the glass back towards the user, providing a shiny silver or mirror-like appearance to indicate vapor space."

Armored Liquid Level Gauge
Transparent Gauge
"Jerguson® Transparent Level Gauges are selected for interface level indication, dirty service or any application that requires the use of a shield to protect the glass from corrosion. A transparent gage is also known as a “thru-vision” gauge since the gauge is constructed with two pieces of flat polished glass assembled on opposite sides of the level gauge chamber. Since the user can see straight through the gauge, it is also easy to view the fluid properties, such as color, whereas this would not be possible with a reflex gauge. The use of an illuminator is always recommended on a transparent gauge."

Selecting an armored level gauge is an exercise in preparing for known and unknown events that might disable your ability to directly read fluid level. Armored level gauges are employed extensively in chemical, petrochemical, and other industries where reliability under challenging conditions is essential. Wherever there are mechanical hazards, an armored level gauge may ultimately prove to be cheap insurance against downtime or delay.

Share your level measurement challenges with a product application specialist. Combine their product expertise with your process knowledge to produce an effective solution.

Thursday, April 19, 2018

Wireless Process Control Instrumentation

Wireless Process Control Instrumentation
Cost cutting is a fact of life for all industries. Whether it be for more efficient operations, or complying to current regulations, the need to build a better mouse trap is always present.

A very promising cost-cutting technology is wireless instrumentation. Wireless provides a compelling argument to change when you consider installation and overall cost effectiveness. Even more so when the application is located in a harsh environment, or where toxic or combustible situations exist. These robust devices provide critical performance data around the clock in the most inhospitable place in the plant, and operate through rain, wind, high temperatures and high humidity.

Untethered by cables and hard-wiring, wireless instrumentation is easier to deploy and monitor. Wireless transmitters are available for monitoring virtual all process variables such as pressure, temperature, level, flow, density, and acoustics. Networks of up to 100 (900 MHz) field devices can be created and then monitored by a single base radio or access point, with a typical communication range of over 1/2 mile. By communicating through the industry standard, Modbus, compatibility between device manufacturers is ensured.
Wireless Instrumentation
Wireless Instrumentation (Accutech and Foxboro)

The most obvious reason for choosing wireless over hard-wiring is the cost savings associated with running wires and cables. Savings estimates as high as 70% can be realized by deploying wireless field devices, compared to the same application using cables. Additional savings are realized when you consider that these devices use batteries and that the cost of adding to a network is borne only by the cost of the new device.

Wireless instruments also provide significant benefits in safety and compliance by keeping personnel out of hazardous areas. Areas that would require occasional human visitation can be safely monitored through remote monitoring.

So, what's the hold up? If the benefits are so clear, and the argument is so strong, why is there still reluctance to embrace wireless technology?

There are three main concerns:

Reliability
Wireless instrumentation must provide the same reliability (real and perceived) as traditional wired units. Every engineer, operator and maintenance person knows wires. Troubleshooting wires is easy, and understanding the failures of wires is basic - the wire is either cut or shorted. With wireless however, air is the communication medium and radio signals replace wires. Radio signals are more complicated than wires in terms of potential problems. For instance, signal strength, signal reflection and interference are all possible impediments to reliable links.

The good news is that radio frequency design is continuously improving, and the use of new and advanced technologies, such as frequency hopping receivers and high gain antennas, are enabling wireless devices to create highly reliable links.

Adapting to Existing Infrastructure
Wireless instrumentation networks have to adapt to the existing environment and the placement of structures and equipment. Most times it's just not practical to relocate equipment just to create a reliable wireless link. This can make it challenging to find the optimum location for a base radio or access point that is capable of providing a reliable communication link to your wireless instruments. Furthermore, accommodating the best strategy for one wireless device could negatively affect links with other devices on the same network.

The challenges of adaptability are being overcome by providing better frequency bands (such as 900 MHz). These bands provide longer range, the ability to pass through walls, and offer more saturating coverage. Other ways to overcome adaptability concerns are through the use of external, high gain antennas mounted as physically high as possible, and also by using base radios with improved receiving sensitivity.

Integration with Existing Communications
Engineers, operators, and maintenance crews are challenged by integrating wireless instrumentation networks with other, existing, field communications systems. The issues of having to manage and troubleshoot multiple networks adds levels of complexity to existing systems. This creates a conflict between the financial argument to adopt wireless instrumentation and the possible costs to increase the data gathering capabilities of an existing system. For instance, SCADA systems need to be able to handle the additional data input from wireless devices, but may not have the capacity. Adding the additional data capacity to the SCADA system can be expensive,  and therefore offset the wiring and cabling savings.

The financial argument for industry to adopt wireless instrumentation networks is persuasive, but its acceptance in the process control industry is slow. Reliability, acclimation, and integration are all challenges that must be overcome before widespread adoption occurs. Eventually though, the reality of dramatically reduced deployment and maintenance costs, increased safety, and improved environmental compliance will tip the scale and drive wireless as the standard deployment method.

Always consult with an experienced applications engineer before specifying or installing wireless instrumentation. Their experience and knowledge will save you time, cost, and provide another level of safety and security.

Thursday, April 12, 2018

Mead O'Brien: Problem Solver, Innovator, and Best Total Cost Provider

Mead O’Brien specializes in valves & valve automation, steam & hot water products and systems, instrumentation products, skid designs, field services, surveys, assessments, and consulting. The extensive product and application knowledge possessed by the Mead O'Brien sales force projects to all or part of ten states in the Midwest which includes Missouri, Kansas, Nebraska, Iowa, Oklahoma, Arkansas, Texas Panhandle, Southern Illinois, Western Kentucky, and Southwest Indiana.