The capacity and pressure requirements of blowers in a Water Resource Recovery Facility (WRRF) are determined by the aeration system. When systems are manually controlled blowers often operate at constant flow and pressure day in, day out. When the aeration system is automatically controlled to maintain a set dissolved oxygen (DO), however, the blower’s flow and system pressure vary constantly. Understanding these variations will help designers and suppliers optimize blower performance.
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.
In open end pipe line suspension flow, or dilute phase pneumatic conveying, proper particle velocity is critical to continuing productivity and product quality. Until recently, measurement of actual particle velocity within the pipe has not been practical outside the laboratory. The plant operating personnel depend on a much less accurate metric - estimating the conveying air velocity in the pipe and relating that to particle velocity.
If you want to understand vacuum systems, you have to get out of the ruts, and slog through the mud and bounce over the rocks a bit. If you’re a “compressed air person”, think outside the box for a few pages with me. I am going to borrow some terms from the “pump people” to explain how vacuum systems are similar, yet different from compressed air systems. There are several ruts to get out of. Remembering what changes and what doesn’t, what is controlled, and how to design systems for optimal energy consumption.
Industrial process operating loads and optimal set points are not usually accurately known at the time of design, so often there is significant mismatch between equipment and the process it serves. To overcome this uncertainty, designers typically oversize equipment. Over time, process changes and equipment efficiencies decline, so equipment might be operating less efficiently than at start-up. Or, equipment can be undersized, thereby hampering the entire system and causing other inefficiencies to compensate. For instance, too much steam usage in the dryer section of a paper machine can occur because of inadequate vacuum at the wet end.
The wastewater treatment plant in the Town of Hurlock, Maryland provides service to approximately 2,100 residences. However, the majority of the water treated comes from a nearby poultry processing plant, giving the plant influent a high organic content. That is why the Town of Hurlock replaced its two million-gallon-per-day (MGD) lagoon plant with a 1.65 MGD four-stage activated sludge facility ten years ago. After construction was completed, operating costs of the new plant were significantly higher than before. This meant the town had to get creative in order to keep costs down for their ratepayers.
Bird Island Wastewater Treatment Plant (WWTP) in Buffalo, N.Y., had an inefï¬cient aeration control system that, ironically, had been installed in 1998 as an efï¬ciency upgrade. The operating principle was that air ï¬‚ow to all 32 of the plant’s aeration basins, or zones, would be properly controlled by an average of several Dissolved Oxygen (DO) level measurements taken by DO probes in a few of the basins. However, changes in tank loadings and physical dynamics, along with differences in oxygen transfer rates between diffuser grids, prevented a uniform air ï¬‚ow in the aeration zones.
Multiple vacuum pumps can be running mostly “dead-headed” in the many production systems that don’t require constant flow. Any system that evacuates a small volume and then holds a product down while it is being machined, or sucks a bag shut to seal will spend the majority of its time not moving much mass of air. This type of operation is found everywhere in secondary wood processing, machining, food packaging, and many other industries. Anywhere vacuum is used as a motive force or to evacuate a small volume repeatedly. This article will apply to any of these types of systems- and not apply to constant-flow vacuum applications in the process industries.
ADA Möbelfabrik, headquartered in Anger, Austria, is one of Europe’s largest manufacturers of furniture. Upholstered furniture, beds, mattresses and slatted frames are produced for the Austrian market and for many other European countries in two shifts, using modern manufacturing techniques. The vacuum supply required for securing items to the CNC machining centers is provided via a central vacuum plant produced by Busch. By opting for this vacuum system, ADA has integrated an extremely economical and reliable vacuum supply into the production process.
Vacuum chucks and holding devices have been used in many industries for a variety of purposes, from lifting packages to holding items for machining. With the introduction of CNC routing machine-tools for mass production (of wood furniture, plastics and other non-magnetic materials), there was a need to clamp-down large work pieces on the flat router tables. Mechanical clamping was not an option as it caused damage to the work pieces and didn’t satisfy the need to quickly place items on the table and clamp instantly.
During the summer season, vegetables tend to deteriorate quickly once harvested from the field—or during postharvest stage of the cold chain. In traditional cold chain systems, vegetables are put into a chilled cooler for preservation, a process that requires approximately 12 hours for the product to achieve proper temperature. In some instances, as much as 25 percent of food product in the chilled cooler will decay before arriving at a proper storage area. Fortunately, there is a process for improving the effectiveness of the postharvest stage—vacuum cooling.