Energy savings solutions in glass industry with VPInstruments
In a glass packaging plant, a VPVision system with over 20 compressed air flow meters keeps an eye on compressor efficiency and leakages.
Glass packaging plants use less and less air
When you think of glass packaging, compressed air is not the first thing that comes to mind. But without it, there would be no packaging glass at all. In an average glass packaging plant the need for air can easily exceed 30,000 to 35,000 Nm3/hr. With such volumes, a plant would need over 20 VPInstruments flow meters to measure the production and consumption of compressed air. They would provide a wealth of data to maintain efficiency in the machines and compressors as well as quickly detect any compressed air leakages.
Such plants produce millions of glass containers per year. They use compressed air to drive the glass blowing machines and to blow liquid glass into moulds. All manufacturing companies focus on reducing energy consumption, sometimes up to 50%! Since compressed air accounts for about 30% of the total electrical power consumption of these companies, it makes sense that this is one of their main priorities. In comparison to the entire industry, this amounts to an average of 10%. Most glass plants have separated systems; one for driving the machines and one for blowing into the moulds.
Compressors in most factories are located in so called “compressor rooms”. Such compressor rooms can contain up to ten machines grouped together. There would be a number of centrifugal compressors present; for high pressure and for lower pressure. The high pressure compressors would need additional rotary screws which deliver oil-free air. Since a glass factory runs 24/7, 365 days a year and every single bottle shape needs a dedicated level of air consumption, it is obvious that a compressor management system is vital to ensure the optimum combination of compressors at all times.
Flow meters compare how machines perform
Flow meters can be placed on each compressor, as well as on the main lines to the bottle-blowing machines. There are flow meters that monitor the production and consumption of air. The data retrieved is logged in a system that also keeps track of gas, power and water consumption. This can provide a wealth of data that can be used to develop new energy savings measures. The efficiency of compressors can be monitored by comparing the amount of compressed air produced with the power consumption. As soon as a compressor shows a drop in performance, the root cause can easily be located; for example a leakage or a fouled inlet filter. Using the same method the consumption of compressed air of the bottle-blowing machines can also be analyzed. Flow meters play a huge role in employee awareness about responsible energy usage. The great thing about flow meters is that they respond immediately to any changes in the machine settings and can be linked to other VPInstruments equipment that displays real-time data over a web interface.
Accuracy or trend
Flow meters are easy to install without having to shut down the compressed air system. However, in order to have these meters take accurate measurements, a straight length of pipe before and after their location is necessary. When there are several bends and elbows in the piping, VPInstruments can help to determine which locations are best to install the flow meters at, in order to gain accurate and representative data. There might be a small level of inaccuracy, but the general trends can still be detected.
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Article Glass International
Read also our article about compressed air savings in the glass industry, written by our CEO Pascal van Putten and published by the Glass International magazine: