When conventional piston pumps were threatening quality at one of the major european breweries, Watson-Marlow Pumps Group intervened with its Bredel 25 peristaltic pumps, closed-couples pumps. Brewers use kieselguhr, a sedimentary mineral in slurry form, as a part of the beer filtration process: A pump is deployed to dose the mineral into the filter so it forms a bed on a plate and frame filter. Piston pumps, however, provide the opportunity for dissolved oxygen (DO) to infiltrate the beer during the dosing, altering its taste. Peristaltic pumps, on the contrary, do not have valves or gears, and the pumped fluid comes in contact with the internal wall of the pipe, preventing any contamination. The twin-bearing hub provides sturdiness, and combines the advantages of bare-shaft construction with those of a close-coupled pump. The pump bearings absorb the forces occurring in the pump, placing no load on the gerbox bearings and on the base plates.