Get what you measure
“The current status of the overall PI [process instrumentation] segment is very strong because everyone is trying to automate their processes to become more efficient and add money to their bottom line,” says Denny Petrovich, food & beverage process sales manager at Siemens Industry Inc. “Instrumentation is the first step in the automation process that provides the sensors, whether they measure pressure, flow, temperature or level. “
According to the Measurement, Control & Automation Association (MCAA), in 2013, sales of process instrumentation and automation (PI&A) in the US grew to about $11.1 billion and $1.2 billion in Canada. MCAA is a North American trade association whose members design, manufacture and distribute instrumentation and systems used in industrial process control and factory automation around the world.
“We project 4.1 percent compound annual growth rate in the US and 3.5 percent in Canada from 2015 to 2018,” says MCAA President Cynthia Esher. “Growth products are [those that measure] electronic flow and electronic level.”
She also says forecasters have reported the food and beverage industry has invested in productivity for several years and has achieved many of its objectives. “F&B producers have reduced energy consumption and overhead while achieving a 2 percent increase in total output,” she notes. “That growth in output has been accomplished by plant consolidations and automation, without major capital investment in new facilities.”
She adds that capital funds have been funneled to acquisitions, stockholder buybacks and dividends, and growth opportunities in emerging markets. “Productivity improvements will continue to be a focus of F&B annual spending, which will be a moderate 2.5 percent for both the US and Canada,” predicts Esher.
“Healthy living has brought a change to how manufacturers package and label products, as well as how they brand their products to draw in consumers,” says Petrovich. “Process instrumentation can help in aiding these trends by improving safety and automation.”
Siemens offers a broad process instrumentation portfolio and has products such as the LR560 solids level radar device tailored to food applications. One company that benefited from the use of this device is Carr’s Flour Mill in Maldon, UK.
Carr’s is a 24/7 operation that supplies UK supermarkets and bakeries with 54,000 tons of flour every year, enough for 195 million pizzas. The company has 26 silos located in a residential neighborhood, which limits its receipt of truck shipments to daytime hours.
To monitor the silo levels, workers used to climb eight flights of stairs several times a day and used a tape measure to get the level information they needed. To remedy this situation, Carr’s installed a Siemens SITRANS LR560 radar transmitter for solids level measurement on the top of each silo. The transmitters provide continuous level readings through a 4 to 20mA connection to a central location on the ground, so workers no longer have to climb those stairs every day.
After the different parts of the wheat are separated, the “midds” leftovers are stored in three separate silos and then sold as animal feed to local farmers. The midds silos are very dusty, but the 78GHz high-frequency SITRANS LR560 radar transmitters have no problem “seeing” the material and reporting accurate levels to operators.
Carr’s also installed a number of SITRANS AS100 acoustic sensors to alert operators of no-flow blockages in pipes carrying grain from the receiving area into the silos. In addition, the company removed some existing level switches that were prone to breakdowns and replaced them with more robust SITRANS LPS200 level paddle switches, which have been in service for more than four years at the site without any problems. The switches monitor high and low levels in a small stainless steel service hopper containing gluten.
In another wireless application, Emerson Process Management recently introduced the Rosemount 708 wireless acoustic transmitter and steam trap monitor. “It basically straps onto a pipe with the simplicity of a metal band,” says Deanna Johnson, wireless products marketing manager. “It takes no more than 30 seconds to install and immediately starts communicating the status of the steam trap it’s monitoring.”
The batteries last for a number of years, and because the units are wireless and just bolt on, there’s no need to break into any pipes, run wiring or conduct the kind of maintenance required by traditional steam trap monitoring systems.
“Steam production is a significant operating expense for processing plants, and about 20 percent of the steam leaving a boiler is typically lost through failing steam traps,” explains Johnson. “The Rosemount 708 wireless acoustic transmitter provides accurate measurement and constant visibility to steam traps, eliminating the need for manual inspection, while enabling dramatic decreases in steam trap failures and fuel cost reductions of 10 to 20 percent each year.”
There are many things processors should take into consideration when choosing an instrument supplier. According to Petrovich, “The processor should be confident the supplier’s products feature viability, reliability and profitability. The steps of automation can be a gradual process, so the systems should be modular, so processes can be added to over time.”
“When setting up a system, look for a supplier with a wide range of instruments designed for hygienic processes, as well as options for utility and wastewater,” says Ola Wesstrom, senior industry manager for food and beverage at Endress+Hauser. “In addition, look for standardization, which is an important feature that helps with training, spare parts and commissioning support.”
Ted Kopczynski, field marketing manager at Hardy Process Solutions, adds, “Know what you need and, if you’re not sure, work with a supplier to find out. Don’t skimp on up-front costs; factor in your system’s projected lifetime, the cost of maintaining it and availability of future equipment and connectivity. And, find partners that are easy to work with, not just vendors that are here today and gone tomorrow.”
According to Bill Wilson, hygienic market specialist at Anderson Instruments, flexibility is another factor to keep in mind. “Probably one of the biggest challenges is keeping pace with consumer tastes and trends,” he explains. “For example, one of our customers and a large dairy decided to launch a rehydration product based on milk-based powders instead of the regular water, sugar and flavorings. Adding powders meant a significant change in production methods—temperature, pressure, flow rates and other things—for this new product.” Wilson says PI equipment that can be reconfigured to adapt to changes like these and be compatible with a wide number of control systems can save producers a lot of time and money.
Anderson’s MPF pressure transmitter is a good example. Essentially a pressure sensor, it is distinguished not only by having a high turndown capability (being able to go from 500 psig to 50 psig, for instance), but also by maintaining the same percentage of calibrated accuracy at any turndown level the producer desires.
Anderson’s ITM-3 turbidity sensor is another example of flexibility. It’s often used by producers with a number of changeovers throughout the day that don’t want to waste startup water or product due to time-controlled phase transitions. The infrared optical sensor uses back-scattered light to detect suspended solids as soon as they appear in the pipe, enabling producers to ignore time control and make changeovers with zero waste of water, product and money.
Wolfgang Stueber, industry manager for food and beverage at ABB Automation in Frankfurt, Germany, notes that successful food products are often copied within six months, which is another reason control systems must be very flexible. For instance, many food producers still use batch processes, so control systems should also carry batch features.
ABB Automation provides instruments designed for food and beverage processors, including sanitary temperature sensors and pressure transmitters, hygienic volumetric and mass flow meters, control room products and sanitary control valves with positioners.
Hardy’s Ted Kopczynski says his company’s new H1 6600 weight processor system is a good example of both modularity and standardization; it delivers up to 30 channels of continuous weight readings to PLCs, PACs and DSCs over a single Fieldbus network connection. Consequently, it’s ideal for applications that require more than one channel of weight, such as inventory tank farms, batching systems and multi-head filling machines. Each channel processes signals from up to four connected load cells that output the entire system weight data over EtherNet/IP, Ethernet TCP/IP, Modbus RTU, Modbus TCP or Profibus-DP.
Connectivity is one of the most important areas Hardy is watching. Kopczynski notes a trend from batch to continuous processing to help meet this need. “The PLC/PAC/DCS is doing more of everything. We see a trend away from individual weight controllers to processors that have no I/O and just send accurate data to the plant control system, either over an OPEN network or directly via a plug-in module of the PLC/PAC.”
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