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Slide 15 of 69

Notes:

    Conflow Ltd of Nottingham design and manufacture specialist water systems for dust suppression, fire suppression and hydraulics for underground coalmining. The major hazard in a coalmine is fire and therefore materials used in mining products must not support combustion, which usually eliminates plastics and aluminium. Two metals that are readily available and meet this criterion are brass and steel, Conflow chooses to specify brass because of its corrosion resistance to water, its machinability and castability. An additional property of brass that makes it ideal for underground applications is its non-sparking property. The company’s products are unlikely to come into contact with items that will generate sparks in their normal operating environment, but it is reassuring to know that if the products are accidentally struck by another metallic item no sparks will be generated.
    A typical example of a product that benefits from the above properties of brass is the company’s Emulsion Mixer, which mixes and supplies a constant and accurate percentage mix of soluble oil and water. The resulting mixture is used as fire resistant hydraulic fluid to power the coal face roof supports. The mixer operates without electrical power, an additional safety feature, driven purely by its inlet water supply. The head, which is 150mm diameter is readily and speedily turned and machined at high speeds from free cutting brass bar, while the base is efficiently machined from a brass casting produced in the company’s own copper alloy foundry.
    The benefits of machining large brass items in addition to the timesaving are reduced tool wear and lower power consumption i.e. less powerful machines tools required. The corrosion resistance of brass eliminates the need for protective coatings allowing all parts to be immediately assembled after machining, reducing manufacturing time and buffer stocks. The swarf produced during machining is readily recycled and commands a premium price.