Power Transmission
The precise servo motion control of the system became a critical factor in the final design. In order for the machine to offer up to 12 axes of motion, component synchronisation had to be tightly controlled so the testing would be accurate. “Each nozzle is roughly five inches from the face of the part,” adds Cooper. “Since the two nozzles face each other, they have to be lined up. We were able to make streams of water, which are each manipulated by five axes of servo motion, concentric within 0.02 inches.”
the use of pneumatic automation, the non-return valves had to be held open continuously via the pumps. This lowered the delivery rate by up to ten percent. The Sindelfingen wastewater treatment plant now achieves
the same pump delivery rate as before with significantly lower energy consumption, saving 89,469 kWh or €11,300 on energy costs per year. This corresponds to a total saving of two percent of the entire plant’s electricity demand. The pumping station is now more clearly laid out and the system requires less space.
Fig. 3. The ultrasonic scanning system at Marietta NDT utilises two sets of jets that face each other.
Path planning
Marietta NDT used drive and control components from Bosch Rexroth. Digital servo drives and controllers, profiled guide rails and pneumatic components allow the machine to follow intricate path planning for scanning complex, curved objects with tightly controlled motion tolerance. “The high-quality controllers are reliable and easy to
programme. They can also accommodate the large number of interpolated axes of the machines,” continues Cooper. In addition, the controllers generate minimal overall electrical noise to minimise ultrasound interference, producing a higher quality image than was possible in the past. The pneumatic components include a vacuum generator to remove air from the nozzle which also improves the quality of the ultrasonic scans. Linear guide rails also contribute to the overall rigidity and
accuracy of the machine. If the machine is not stiff enough to handle the squirter system, it will begin to vibrate, which adversely affects the testing. From a maintenance perspective, the linear guide rails are an ideal solution due to their longer lubrication interval, dual rail datum and interchangeable runner blocks. In addition, the rails are plated with dense chrome to resist rust, a crucial consideration for a machine that incorporates water. In another pneumatic application, a wastewater treatment
plant in Sindelfingen near Stuttgart that treats wastewater for 250,000 inhabitants claims to have achieved an energy saving of €11,300 a year with pneumatically actuated knife gate valves from Festo. The process valves are distributed throughout the entire plant, sometimes in locations that are not easily accessible.
No non-return valves
There are six centrifugal pumps in the pumping cellar each with a power consumption of 90 kW and a delivery rate of up to 500 l/s at a delivery height of eight to nine metres. Before
Fig. 4. Hydraulic consultant Stephen Barrett says the boundary between mechanical, electrical and control technologies have become so blurred as to be indistinguishable.
The noise level has also been reduced and because the knife gate valves close tightly, there are no more undetected leaks. When closing the knife gate valves, no water hammers occur and thus no vibrations in the pipeline that have negative effects on service life. Gas bubbles that form when the pump unit is at rest can now escape when the knife gate valve is opened. This ensures the pump units start automatically. Pump efficiency is key in any industry and Princes Gate
Spring Water also claims to have achieved significant energy savings and production improvements at its Wales-based bottling plant. By replacing its oil-lubricated compressor installation with Atlas Copco oil-free machines and AIRnet pipework, it ensures the purity of its natural water products. The production operations need a constant 108 l/s supply of
high quality compressed air at a pressure of seven bar to meet the demands of the process line’s low-pressure air users, such as air cylinders, manifolds, filling equipment and inking machines - all of which contribute to an annual output of 55 million bottles of spring water from the company’s on-site source. Endaf Edwards, Princes Gate’s Operations director said:
“The Atlas Copco equipment is proving to be very efficient. It produces the 100 per cent oil-free, high quality, dry air we need and is extremely reliable.” ●
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