Operating the vacuum system at higher levels (then necessary) affects the needed volumetric flow to compensate for leaks. This required compensation of volume (ACFM) must be added to the nominal production flow demand. The ambient air leak into the system will expand to the highest vacuum level, which is known as the “Expansion Ratio.”
An envelope manufacturer is upgrading their vacuum system to include a new VSD controlled pump. As part of the preparation for the installation, an energy baseline was developed, and leakage survey conducted. The auditor used a newly developed acoustic imaging camera as well as a basic ultrasonic leak detector gun. This article describes what was found and some of the challenges faced in detecting leaks in a busy plant.
What is vacuum as used in the manufacturing/industrial sector? The clearest answer is – a contained space with gaseous pressures much less than surrounding atmospheric pressure. Atmospheric pressure (ATM) is expressed in many units of measure. At room temperature a cubic foot of contained air at sea level – the random movement and molecular impact on the walls of the containment vessel equal a force of 14.7 psia for every square inch of the walls.
A paper machine carefully removes water from the paper sheet. Some of this water removal is done by passing air through the sheet, thus moving the water from the sheet to the wire. Air is moved by creating a pressure differential across the sheet. This is normally done by putting the sheet on a wire and then putting a box under the wire and then evacuating the air from the box. The resistance of the air movement through the sheet and wire causes the pressure drop from the machine room to the box.
Many of us are familiar with sizing vacuum pumps based on throughput, process pressure requirements, chamber size, pump down times, conductance and leakage. In a lot of cases, humidity becomes an afterthought and unexpected things happen. Some of these unexpected things we learn to live with, like emulsified oil. In other cases, the unexpected things prevent the pump from performing the job it was intended for.
Vacuum can be used in many ways for the meat processing and packaging industry. From mixing ingredients to evisceration (removing organs, excess fat, bones, etc.), to the washing/preparation of the meats or even in the packaging of the meat itself, vacuum is critical to the industry.
When Craft Brew Alliance (CBA) set a goal to dramatically reduce water consumption at its Widmer Brothers Brewery in Portland, Oregon, it focused its efforts on its bottling process – and implemented a solution engineered by Atlas Copco that saves 5,000 gallons of water per day. In addition, it saves the craft brewer $39,000 per year, thanks to the elimination of water treatment costs and reduced energy use.
DMK Deutsches Milchkontor GmbH produces sliced cheese and Mozzarella at its production facility in Georgsmarienhütte, Germany. The various types of sliced cheese and Mozzarella blocks are vacuum packed after processing in several packaging lines. The vacuum supply for the packaging machines is provided by a Busch centralized vacuum system, which supplies both the packaging lines and the thermoforming machines.
Choosing the right vacuum supply can lead to huge cost savings in plastics processing. Mar-Bal, Incorporated has undertaken a critical review of the existing vacuum supply for injection molding when moving to a new plant and has collaborated with Busch, LLC to find a solution that will achieve savings in energy, maintenance and production times.
This article will focus on optimizing the demand-side so the centralized “supply-side” (the vacuum pumps and controls) can then run at a lower energy and maintenance cost. First, I will start with a simplified model of a vacuum pump system demands. See Figure 1 for a one-pump/one-demand simplified system. See Figures 2-6 for some typical controlled and uncontrolled demands. The symbol with the three lines is an orifice, a hole essentially. I am defining three types of system demands adding up to the total demand on the vacuum pump.
Electric utility incentive programs encourage industrial and manufacturing companies to reduce power consumption by paying part of the cost to upgrade to more efficient equipment. It’s a great concept, but many customers only go after low-hanging fruit, such as upgrades for lighting or air compressors, and go no further.