Process cooling and materials handling specialist, AB Systems, has a reputation for surpassing clients’ expectations, and the company’s latest cooling tower replacement project for injection moulding and extrusion firm, DHM Plastics, is no exception. As well as meeting the customer’s original request for a HSE compliant water cooling tower, AB Systems identified further opportunities for DHM to benefit from improved plant efficiency and performance. As a result, AB Systems upgraded DHM Plastic’s entire cooling system, including the steel support structure, pumps and pipework, and integrated a new bespoke central control system – and completed the project in just one weekend, despite extremely challenging logistics, to ensure business continuity for this forward-thinking plastics manufacturer. Thanks to AB Systems, DHM Plastics is on track to save more than £20,000 a year in electricity costs and over £3,000 a year in mains cold water and chemical treatment costs.

DHM Plastics, which is part of the Aliaxis Group, manufactures high quality products for leading brands in the construction industry, including Durapipe, Hunter, Marley Plumbing and Drainage Solutions, and Multikwik. Originally the company approached AB Systems to look for a solution to replace its ageing 25 year old cooling tower at its Lenham depot in Kent, including the steel support structure which was badly corroded. The pumps were also past their best and the control system was very inefficient. In order to optimise the efficiency of the cooling system and ensure continued compliance with the HSE’s current legislation and Approved Code of Practice (ACoP) L8 (‘The control of legionella bacteria in water systems), AB Systems’ proposal included a complete upgrade of the entire system, as agreed with DHM Plastics.

Because of time constraints and certain logistical challenges, planning had to be exact. Firstly, DHM Plastics’ plant usually operates five days a week, and as the cooling tower is critical to the plant production machinery, it was important for the project to be completed in just one weekend in order to minimise disruption to the plant. Secondly, the cooling system is located at the bottom of a confined dead end on an already narrow site, so the nearest that AB Systems’ engineers were able to place the company’s 75 tonne crane was 25 metres away from the location.

In order to meet the limited timeframe, AB Systems’ engineers made detailed plans for all the required parts and equipment to be engineered, constructed, and to arrive on site beforehand, thus enabling the installation to proceed over the weekend 48 hour period. New steel support platform walkways and safety handrails were designed and constructed offsite by AB Systems, then galvanised to prevent future corrosion issues. “After the initial survey, our engineers specified that all equipment used in the installation had to be constructed entirely from stainless steel and then galvanised to ensure longevity,” explained Jeff Day, Managing Director of AB Systems.

The installation process involved the removal of the old tower, pumps, control and steel support frame – which AB Systems disposed of responsibly for the client – as well as the erection and installation of a new state-of-the-art fully stainless steel cooling tower from AB Systems, vertical ladder access points, protection rails, walkways, pumps modules, fan and control panel, plus all pipe and steelwork. Due to the confined workspace, AB Systems’ crane driver had an extremely limited field of vision and so was entirely reliant on hand signals and communication from engineers located at strategic points around the site in order to manoeuvre the 3 tonne cooling tower and 2 tonne steelwork frame support and walkways into position.

Despite the extremely challenging location and timeframe, the installation went seamlessly. “Dealing with such restricted access and a short window to complete the installation could have been a logistical nightmare. In fact, the new control panel was the only job we could complete before the planned shutdown, so the installation had no room for error or unforeseeable problems arising during the refit. To ensure it all went well for our customer, we invested a lot of time meticulously planning the installation in advance of arriving on site,” commented Mr Day.

The HMI touch screen control system designed and installed by AB Systems allows the entire cooling system to be operated and controlled at one central point. What’s more, DHM Plastics’ engineers now have access to detailed, real-time information at the touch of a button, something that enables the customer to closely monitor the system and thus ensure that water and energy usage is optimised. In addition, it has made compliance with HSE regulations, especially for legionella, much easier to maintain.

Thanks to AB Systems’ proactive approach to the project, DHM Plastics is experiencing marked improvements in plant productivity, performance and efficiency. Electricity savings, which are set to total more than £20,000 a year, are primarily due to the cooling system’s new pumps – which are correctly sized for the system and offer increased energy efficiency – as well as the new inverter driven fan motor. Along with savings to water and chemical treatment costs – both of which help the company to meet environmental targets – DHM Plastics is on track to save more than £23,000 annually. What’s more, the entire cooling system is now HSE L8 compliant.

Tim Sandberg, Business Improvement Manager at DHM Plastics, said that the company is delighted with the results of AB Systems’ work: “AB Systems went over and above to ensure that the project was completed over a weekend in order to minimise disruption to the plant. It wasn’t an easy task, especially given difficult on site access, but all credit to Jeff’s team of engineers who assisted with the installation – it was carried out safely and seamlessly, despite the inclement weather!”

He continued: “Not only does the system perform well, but the choice of materials means it looks the part too, reaffirming an important message to the people on site that we are still growing and investing as a company, despite the tough times. Superb workmanship and technical expertise is evident throughout the new system, and the new cooling tower technology is advanced to ensure that we have a long-lasting, highly efficient solution. We’re also extremely pleased to be benefiting from significant cost and water savings, especially in light of our own environmental targets. I wouldn’t hesitate to recommend AB Systems to any company looking for a professional, dedicated and expert team – that also relish a challenge!”

In conclusion, Mr Day explained: “The key to success for this installation was to have all equipment delivered on site the week before the planned shutdown so we could meet the two day timeframe. The project also involved working over a pit of water while ripping out the old frame and tower, so was quite precarious at times, but with a fantastic team effort and risk assessment planning, the job went ahead smoothly and on time, with minimal disruption to the plant.”