Bottle Maker Uses Data Loggers for Low-cost Air Waste Detection

Saint-Gobain Containers uses low-cost energy data loggers to detect compressed air system leaks so they can be repaired.

Saint-Gobain Containers is the world's largest building materials company, and a global leader in the production of high-performance materials and glass containers. In North America, the company employs 22,000 people in more than 350 locations.

Among its products are wine bottles and other containers for the food and beverage industry. The bottle-making process requires use of compressed air, in some fashion, on or around every piece of production equipment.

Leaks, a frequent problem in compressed air systems, create inefficiencies that add to manufacturing costs. Saint-Gobain Containers set out to find an effective approach to detect system leaks that did not require a large capital investment in monitoring and management equipment.

The Madera, California facility, which produces millions of wine and champagne bottles per year, designed a low-cost system using data loggers and flow meters. The company’s investment of less than $5,000 in monitoring equipment is ultimately expected to yield tens to hundreds of thousands of dollars in annual savings. Saint-Gobain Containers estimates that it will reduce 10 to 50 cubic feet per minute (CFM) from each piece of equipment placed into the monitoring system.

DOE recommends monitoring
Compressed air is a vital utility in a wide range of industrial processes. But these systems use a significant amount of energy, so if they do not operate to full capacity – if air is leaking out – energy costs can mount. As a result, the U.S. Department of Energy’s Office of Industrial Technologies recommends that all facilities with compressed air systems adopt aggressive leak detection and prevention programs, with quarterly system monitoring.

In addition to wasting energy, leaks create other problems. They can cause drops in system pressure, which makes tools operate less effectively. Or leaks may make equipment cycle too frequently, resulting in higher maintenance costs and shortening equipment life span.

A compressed air system in good working order should lose no more than 10% of air and power capacity, but it’s not unusual for systems to lose as much as 20% to 30%. Leaks are most likely to occur at joints and fittings, and can often be averted through a simple tightening or replacement of connections.

Detecting equipment leaks with data loggers
In complex or large systems, leakage monitoring and detection systems can be costly and time consuming. Knowing this, Greg Rhames, an energy engineer at Saint-Gobain Containers’ Madera, California plant, set out to find a low-budget way to discern and reduce energy waste from three 1,250 horsepower compressors that run 24/7.

Rhames decided to pursue what he describes as monitoring from “an equipment-based perspective.” This runs contrary to the more common method in the industry of placing large meters of varying types close to the supply side of a compressed air system. Rather than monitoring total system output, he sought to analyze performance of individual pieces of equipment, pinpointing problems at their source through measurements taken with data loggers.

“Instead of looking at this from 300,000 feet, we were looking at it from 1,000 feet,” he said. “You can get solid results by going to the equipment and working your way back versus monitoring at the supply side. If you monitor from the supply end, you have no resolution on issues causing the air leaks downstream.”

Rhames devised a monitoring system that uses an Onset HOBO® Energy Logger, a portable data logger that includes snap-in “FlexSmart” modules that convert signals from nearly any type of sensor. The 15-channel data logger can measure compressed air, gauge pressure, kilowatt-hour output, voltage, current, air velocity, temperature, and a range of other parameters. For Saint Gobain Containers’ purposes, Rhames needed the data loggers to measure the CFM consumption of every piece of equipment in the plant that uses compressed air. To accomplish this, Rhames installed compressed air flow meters from CDI Meters, the 5200 Series with remote displays, which he connected to the FlexSmart modules. As the project continues, additional meters will be installed at each compressed air receiver throughout the plant to allow departmental isolation and monitoring of system air pressure.

Rhames placed two data loggers in one of the centralized equipment control panels. During installation, he performed a 10-minute logging test and gathered the results to verify all components were operating correctly. He then redeployed the logging devices and left them to record for 24 hours. He recorded the air flow measurements every two seconds.

Since the data loggers are portable, he was able to unplug the modules, remove the loggers, and bring them into his office to download the data into Onset’s HOBOware® Pro graphing and analysis software package. The software provides a quick readout of the collected data, which can then be exported to Microsoft Excel, which he used to manipulate the information. Using both spreadsheet and graphical formats, he set a baseline measurement, studied the effects of various corrective actions, compared historical records, and established benchmarks. Most of the machinery cycles between 2 and 15 seconds, depending on what’s occurring. By stretching the data out over the course of the day, anomalies in the system became apparent.

The individual pieces of equipment should lose no more than 2 to 0 CFM. If there is a loss of more than 10 CFM, “you should really analyze the equipment and see where you’re losing air. Find it, fix it and bring it back down to tolerance,” he said.
“The data so far shows we’re losing 20 to 30 CFM because of leaks,” he added. “It’s amazing how much waste occurs on one piece of equipment. The data loggers make it immediately evident.”

Large savings achieved quickly
Using the energy logging equipment, Saint-Gobain Containers identified the worst compressed air leaks and repaired them, resulting in a 10 CFM decrease in compressed air waste. Rhames calculates that the facility will save $2.24 for every CFM of High Pressure air preserved. As a result, “the savings could be huge -- possibly tens to hundreds of thousands of dollars annually,” he said.

By working on a small budget, Rhames avoided the delay common in most corporations when requests are made for large capital expenditures. He was able to get the project up and running in days, rather than months or years. The data provided by the Onset data loggers allowed for quick reaction to correct the leaks. Thus, Saint-Gobain Containers was able to start saving energy – and money – sooner than it would have with a larger, more costly system.

Use of the data logger will now be standard operating procedure at the facility. Data gathered and compared, during and after leaks are found and repaired, will be applied to achieve a standard minimum (CFM Consumption) benchmark for all similar equipment.

The data logger system proved to be an effective way to provide real-time analysis that was previously only attainable with a larger, much more expensive system. The project showed that a large industrial facility can institute a comprehensive compressed air monitoring system, and a compressed air waste reduction system, with economical, equipment-level monitoring and logging devices.