Wienerberger Building Solutions produces bricks and clay blocks and clay roof tiles. It has 14 production sites in the UK, including its Denton Plant, which is based near Manchester. When problems started to occur with the Denton compressor system and vacuum pump system, Miles Coppinger, director of production in the north at Wienerberger, looked to rectify the problems by seeking out the services of compressed air and vacuum supplier Atlas Copco.
The primary function of the compressor installation at the Denton site was in brick production. Seven-bar air was supplied to pneumatic cylinders that power the clutches of the mixers blending additives with the basic ground and milled clay processing operation, as well as those of the extruders. This, together with the final sandblast treatment, determines the performance and quality of the finished products.
However, the existing compressor system had started to become unreliable and this unreliability had led to a stark choice between carrying out motor rewinds or taking the longer view and replacing the compressors with alternatives.
The site was also experiencing similar performance and efficiency issues with its vacuum pump system, which was employed to remove air from the brick material before extrusion, forming and kiln firing. Operation was intermittent because of problems running cooling water through the pumps, with the design offering limited opportunity for corrective maintenance.
With Atlas Copco on-board, the first task undertaken involved a week-long data-logging procedure to determine the energy usage of the existing plant, along with the air demand requirements and the system’s capabilities, in order to establish a flow profile.
The results demonstrated an opportunity to make energy savings and reduce the company’s carbon footprint, and the recommendation put to Wienerberger was for a complete replacement compressed air installation.
This would comprise an Atlas Copco GA90VSD+FF rotary screw compressor, a fixed-speed GA 75+ rotary screw compressor together with an FX15 refrigerant dryer, a 3,000-litre air receiver with electronic zero-loss drain, plus ancillaries, including an OSC oil/water separator, all connected by an Optimizer 4.0 central controller.
To minimise pressure drops in the air network, the existing four-inch galvanised pipework was to be replaced with an Atlas Copco AirNet 80mm (3 ¼ inch) modular aluminium pipework system, installed by Pennine Pneumatic Services. The compressors would also feature winter and summer ducting to aid heat recovery and to direct hot air into the factory during colder months, via manual vent switching.
The Denton plant had also previously used liquid ring vacuum technology for clay extrusion. (This technology features an eccentrically mounted impeller that rotates in a housing partially filled with operating fluid). According to Atlas Copco, it required a more efficient solution that would also allow it to remove the risk of Legionella (bacteria causing a lung infection) from the cooling towers used to support the existing liquid ring pumps. The new vacuum system needed to be suitable for the high water content and high ambient temperatures involved in the clay extrusion application.
Based on the energy saving potential and the option to remove the cooling requirement, Wienerberger chose an Atlas Copco GHS585 VSD+ Humid oil-sealed, rotary screw vacuum pump to meet the site’s requirements. The ‘smart’ features of the system allow Wienerberger to link directly into the application’s PLC system, providing direct control of the pump when the production line is running.
INSTALLATION & RESULTS
The whole operation was carried out in three phases and included solving an accommodation problem in siting the new equipment. This is where the bike store at the site came into the picture.
Phase one saw the GA75+ compressor and FX dryer back-up units installed in the bike store, and eventually re-sited in the old compressor house from which the original units were removed.
The second phase saw the new main duty compressor system equipment in place and commissioned before completion of the final phase, involving removal of the redundant units and installing ducting.
At the same time, the central control and monitoring system was linked to the newly installed Atlas Copco GHS585 VSD+ pump, which solved the company’s air extraction reliability issue.
The makeover project is said to offer a potential payback within only two years; the estimated energy saving from the first two phases is said to be in the region of £38,000 per year. An additional benefit derived from the new installation is that Wienerberger is said to have reduced its carbon footprint by almost 200,000 kg per annum.
Furthermore, it has now become the Wienerberger parent company’s policy to switch from liquid ring vacuum pumps to rotary screw vacuum pumps in all its production plants.
Coppinger comments: “By replacing the old equipment, we avoided the cost of overhauls, which would have amounted to at least another £30,000. Naturally, I will keep a sharp eye on continuing performance and will be establishing data from sensors both in terms of kW/hr/m3 air power costs, but also as power related to the total volume of product output for any given period.”