Cat Pumps for New Cleaning Plant in Scottish Barley Maltings
The redevelopment of the Bairds Malt Arbroath malting has provided Cat Pumps with the opportunity to continue its supply of triplex positive displacement plunger pumps into the maltings market.
The process involves forcing water at high pressure through nozzles attached to the slowly rotating machinery to remove matter attached to the malting floor and the vessel’s walls. (Image: Cat Pumps)
Bairds Malt operates five malting sites across the UK, stretching from Inverness in the Scottish Highlands to Witham in Essex. The Arbroath maltings opened in 1970 specifically to supply the local distilling industry. Today, Bairds’ total annual production capacity is more than 250,000 tonnes.
In 2008 Bairds Malt invited Cat Pumps to propose a high pressure wash pump system for their Arbroath maltings which was to be replaced with a state of the art facility capable of producing over 300 tonnes of distilling malt every 48 hours and an annual production of 57,000 tonnes. Formally opened in 2010, the new maltings includes a grain drying complex incorporating two continuous tower barley driers capable of drying 40 tonnes per hour.
The germination process is the "control" phase of malting and continues for four to five days and during this period the grain is kept cool and carbon dioxide is removed by blowing streams of cool, humidified air through the bed. The grain is turned regularly by rotating augers to prevent rootlets matting and to maintain a loosely packed grain bed. The maltster manipulates the germination conditions to vary the type of malt being manufactured.
Cleaning the germination vessels and machinery is an essential operation after every batch. Mould can form and if left for too long it becomes difficult to remove. The cleaning process takes place every two days on one vessel or two days on both vessels and usually lasts for two hours. The process involves forcing water at high pressure through nozzles attached to the slowly rotating machinery to remove matter attached to the malting floor and the vessel’s walls (Fig 1). Bairds Malt provided their preferred pump suppliers with a specification of the flow rate and pressure required and Cat Pumps responded by proposing a single skid incorporating two of their model 6767 triplex positive displacement pumps. Together, these provide a constant flow rate of 400 litres/minute at 80 bar and by offering two pumps in tandem, Cat Pumps were able to provide Bairds Malt with the performance specified at minimum cost, with the added advantages of lower weight, simplified servicing and overall lowest life-cycle costs of ownership.
The contract to design and construct the complete high pressure pump skid was duly awarded to Cat Pumps, who incorporated drive motors and transmissions as well as pressure regulating and relief valves, all interconnecting pipework, service isolation valves and pulsation dampeners.
Bairds Malt was also required a small additional high pressure wash-down system incorporating hand-held lances to clean other parts of their equipment. Cat Pumps assisted in specifying the flow rate and pressure required and incorporated one of their compact model 7CP positive displacement pumps on the same skid to save space. This pump provides an output flow rate of 41 litres/minute at 50 bar.
At the request of Bairds Malt, Cat Pumps’ general manager Brian Hubbard attended the site on start-up day and successfully commissioned the pumps, leaving the system fully operational. Cat Pumps’ designs, components and skid packages are built to last and with these three pumps Bairds Malt are attaining not just low levels of maintenance but also the high levels of operating efficiency that triplex positive displacement pumps can provide.
Source: Cat Pumps Ltd.
