processing control Archives

A Guide to Ratemeters

Posted on August 17, 2016March 2, 2017 by admin

Measuring flow requires that you have adequate means for reading information. Ratemeters and totalizers offer a user the ability to understand exactly what is happening within the mechanisms of flow metrics. Without these handy gadgets, measurement is far more difficult. It is important not to rush through this facet of flow measurement, as you might find that there are a number of variables to consider when choosing a ratemeter and totalizer. In the following, you will read about several different kinds of ratemeters.

The MINITROL

912-MRT The 912-MRT, otherwise known as the MINITROL, is a ratemeter with six digits and a two level, five digit preset alarm control. There are two inputs, A and B, which can be calibrated in three different ways:

“A” subtract “B”
“A” add “B”
“A” and “B” as separate totalizers

Moreover, the MINITROL can handle a whopping 10,000 pulses per second. With five digits and a floating decimal, you can measure in true blue engineering units with the rate set in terms of seconds, minutes or hours. You can also toggle between the current rate and total without disrupting the count. This ratemeter is perfect for all kinds of flow measuring fun.

918-RTP

918-RTP If you are searching for something a little more futuristic, you might want to look into the 918-RTP, which boasts a 2 X 16 backlit LCD display with a ratemeter and totalizer that you can preset by way of two pulse inputs. You can even connect this piece of equipment to a network for data acquisition. Like the MINITROL, the 918-RTP has two inputs (A and B), each of which can define up to 16 points of K-factors. What does this mean? Well, simply put, this allows for a greater degree of accuracy, which makes this ratemeter worthy of consideration for future purchase.

The KEPTROL

The 920-KRT8, known as the KEPTROL, is a serious meter allowing for 20,000 pulses per second. It is faced with a .55” screen that displays both numbers and letters. With a 16 point K-Factor this unit can give majorly accurate readings. Perhaps the most wondrous attribute of this ratemeter is its capacity to transmit data to remote totalizers, computers, programmable controllers and many other kinds of digital data storage devices. To top it all off, the KEPTROL offers you the ability to protect your information with a password. This can be useful if you are storing your equipment in a place that is accessible by other people or if the measurements belong to patented research that you want to keep away from the vying hands of competitors.

You might find that there are a lot of overlapping features, such as two programmable inputs, toggling capabilities, security features and alarms. Because of these shared features, it would be advisable to seek out an expert to help guide you through the tedious work of researching the many kinds of ratemeters. He or she can help you determine what you actually need. After all, an LCD screen might look sleek, but upon closer examination you might discover that it is actually superfluous.

Flow Control and Pressure Measurement

Posted on August 16, 2016 by admin

Control operators rely on pressure readings to monitor the state of processes within the facility. Usually those employees responsible for recording the measurements read from Bourdon tube gauges and are manually entered into the data management system. Other than continual monitoring pressure readings can hint at upcoming maintenance.

Bourdon tubes gauges are a long standing tradition in pressure measurement, they are simple to install, operate, and low cost. Because of the little thought given to these gauges, they often are maltreated or neglected. Process fluids can be corrosive and pressure spikes can cause leaks or ruptures, leading to shortened lifespans for Bouron tubes. Fluid filled gauges can overcome some of the wear and tear from constant surges in pressure, but hearty taps from operators checking the gauges can cause more damage.

Upgrades do exist for Bourdon tubes, mainly in the form of wireless transmitting models, but this feature can cost up to 4 times as much per gauge. Ultimately the decision to use wireless models or traditional gauges depends on the design requirements of the system. Data from wireless gauges must be routed through a gateway connected physically to the data management system, and can only handle a specific maximum of devices through each gateway device.

Click here for the full article by Wally Baker.

PID Controls

Posted on August 15, 2016 by admin

PID control stands for proportional, integral, and derivative control. This type of process management is used to maintain set parameters, and works well for temperature or motion. All three portions of this control setup manage whatever parameter you desire in different manners.

Proportional control controls how far the measured parameter is from the set parameter. In terms of temperature it will tell you how far off from ideal the process is running; i.e. +1.85 °F or -.07°F. Managing the process with proportional controls alone will work, but the systems will swing between over- and under- correcting.

Integral controls are added onto proportional controls to factor in timing into the setup. By measuring the time between measurements of the parameter the system can determine the speed at which the motion or temperature are changing; i.e. -.1 °F/second. By knowing this measurement the system can then account for this with more precision, cutting down the amount of over-correcting. Still this combination will need one final layer to appropriately maintain the parameter dynamically.

Derivative control measures the acceleration of the parameter, in effect the speed at which the speed is changing. With this level of control, the parameter changes can be dampened and returned to the set point reliably. In terms of motion parameters, with a properly installed PID control system a ball bearing can be kept from rolling off a glass plate even when pushed by people.

Click here for the full article and tuning tips by Mark Bacidore.

Tell Your PLCs from Your IPCs

Posted on August 2, 2016 by admin

Before the personal computer, operation controllers had PLCs, programmable logic controllers, to manage what machinery was doing. Now we have PACs and IPCs to add to the mix, and the confusion over which does what and where each is best grows.

A PLC is the origin of control specific machinery, built to last through extreme environments and relaying on/off instructions to machinery based on input from sensors. The most applicable situation is amusement park rides. An operator pushes the command to execute the ride, and the PLC takes over from there. Some can be as simple as automating the order of events of one precise schedule, and some can manage variables to adapt the schedule as needed.

PACs are programmable automation controllers, and these do much the same as PLCs but without the option of inputs. A PLC can function as a PAC, but usually the reverse is not true.

An IPC is an industrial personal computer, and these carry out much more computationally heavy tasks. One common situation that IPCs excel at is mixes of materials that vastly change properties at different ratios.

Click here for the full article by Dan Herbert.

Net Positive Suction Head and Cavitation

Posted on July 26, 2016 by admin

Centrifugal pumps shine when a processing line may require a wide range of flow rates. Altering the flow rate by closing or opening a discharge valve will stress a pump by causing it to operate outside of its best operating point. When the situation requires significantly more or less flow than the pump is producing net positive suction head, NPSH, cavitation, or vibrations can cause irreparable damage.

As a centrifugal pump operates pressure changes from inlet to outlet; negative pressure “pulls” fluid into the pump, and positive pressure “pushes” the fluid out of the pump. Because fluids may change phase at lower pressures, cavitation commonly occurs near the inlet of the pump. This phase change will cause the pumps to run dry, producing vibrations that wear bearings prematurely. These vibrations are caused by small bubbles returning to liquid as the pressure increases.

To prevent dangerous cavitation, net positive suction head is a measurement of the pressure at the pump inlet above the vapor pressure of the pumped fluid. NPSH is usually 3 to 5 feet, more if possible, meaning that at least 3 feet of head pressure more than the is required by the system.

Click here for the full article by Lev Nelik.

Better Biofuels

Posted on July 22, 2016 by admin

Engineered bacteria is beginning to streamline biofuel productions. The bacteria being used is a strain of E. coli that has been adapted to withstand liquid salt solutions used for breaking down plant matter into sugars. As these cells adapt better to this type of environment, biofuel processing will no longer need to remove the liquid salts from the mixture before introducing the bacteria, the process would be a “one pot method.”

Yields are currently significantly lower as the tests are using less pure sugar than other processes. Further refining of the E. coli strain will hopefully boost the returns seen from this vastly easier method.

Currently, we have only engineered the strain to digest cellulose so it can use the resulting glucose to grow and make the biofuel,” explains Mukhopadhyay. “We can also engineer it to digest hemicellulose, another large component of plant biomass so that it can use the resulting xylose for growth and production also!”

Click here for the full article by ChemicalProcessing.

Signs of a Poorly Constructed Valve System

Posted on July 20, 2016 by admin

Bolts that are too long: If engineers are wasting money on excessively large bolts, they must be cutting corners somewhere.
Non-isolated control valves: Maintenance is always required, if there is no way to easily remove a valve then maintenance is not being done on the valve.
Lack of pressure gauges and connections: At some point it will be necessary to monitor the pressure at the valve. Build with future needs in mind.
No air vent caps: Valves that reduce pressure will buildup air pockets during operation, if this air is not vented you can bet a costly repair will be needed soon.

Click here for the full list of signs by Mark Gimson.

Hydraulic Valves Preventative Maintenance

Posted on July 19, 2016 by admin

Hydraulic systems are dependent on every part within the system, any small leak or failure from one piece will bring the system to a grinding halt. The fluids used in particular systems can even harm personnel nearby or the environment in the occurrence of failure. Valves are critical to hydraulic systems as they control the flow of hydraulic fluid through the system to perform work. A preventative maintenance program should focus on valves more thoroughly than any other component.

Reactive maintenance expects to run components to failure, often valves fail first, and then enact repairs while productivity is zero and then make up for lost production time later. This process is costly and usually fraught with high tensions. A preventative maintenance schedule uses time or specific conditions to “schedule” repairs and replacements. This scheduling process can be in terms of time; i.e. replacing seals and gaskets every 2 years, or it may be based on operations; i.e. after every 5,000 cycles, or both depending on which “schedule” comes first.

Industry data shows that performing maintenance on a scheduled basis is three to five times less expensive than the same repair being made on a reactive basis.

Click here for the full article by Mickey Heestand.

What is Good Control Design?

Posted on July 14, 2016 by admin

A good design to a control room will facilitate efficiency and minimize liability. The design will enhance an operator’s efforts to produce the desired results in production. Since 2000 the International Organization for Standardization has produced a set of standards, ISO 11064, for control room design. Most of these standards deal with ergonomics and layout for the room, and adherence to these standards can greatly protect a company from injury lawsuits.

ISO 11064 helps establish good design standards with measurable results to avoid control rooms like many of us have experienced. Designed control rooms, control buildings and operation camps that feature a user-driven approach, work with ISO 11064 requirements, and integrate architectural, interior design and human-factors elements optimize performance.

First and foremost in the design process focuses on safety; locating the control room outside of blast zones, pathways of heavy equipment, and insecure environments. Further efforts deal with employee access and localities.

Click here for the full article by Mary Ann Lane.

Technology Giants Bolster Industrial Internet of Things

Posted on July 12, 2016 by admin

Microsoft and General Electric are partnering to improve the online cloud industry with the industrial internet of things in mind. GE’s focus on the industrial and manufacturing sectors will synergize with the technological innovation from Microsoft to provide cloud resource servers and analytics on demand for the burgeoning industry of smart connected devices.

“Companies worldwide will be able to bridge the divide between the operational and information technologies that make up the Industrial Internet of Things,” -Microsoft

This collaboration is set to bring analytics from equipment to a wide variety of operations, with even more reliability for future adopters. GE’s cloud platform Predix will be integrated into Microsoft’s Azure for a final service of; Predix of Azure.

Click here for the full article from Tech Times.