Rotary cup burner atomize fuel by throwing it it of the edge of a rotating tapered cup, generally rotated at 2000 to 7000 rpm by an electric motor or air turbine propelled by the primary combustion air. The tapered cup is attached to the end of a rotating shaft and the oil is supplied through the hollow shaft. The centrifugal force causes the fuel to thin out and breakup at the tip of the cup and get atomized by the stream of surrounding air. the rotary cup provide rotational energy and also will atomize the fuel. the result is a rotating cone of fine fuel particles. high oil pressure is not needed and throughput is controlled by a valve in the fuel inlet. turn down ratio= 10:1. The minimum throughput is governed by the fact that sufficient oil must be supplied so that thin oil film is not broken for a stable primary flame. Cannot be used in roof fired boilers.
Since very small needle lift is obtained in the test equipment result in an unequal pressure distribution in the cut off shaft resulting in a hard contact in a small area along with high frequency oscillations, low lubricity of test oil will increase the chance of seizure. Full lift and high lubricity of heavy oil eliminates this risk of seizure during normal operation.( Always open and clean slide type valves before testing as cold sticky heavy oil along with small clearances can cause restriction in the movement of the spindle).
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