| 摘要 |
PURPOSE:To miniaturize the heating area as well as the device of a preheater by a method wherein the source of heating steam is switched by a difference between the pressure of heating steam source and a pressure in a steam type air preheater. CONSTITUTION:Steam, entering into a steam type air preheater 2, is switched to an auxiliary steam, fifth extraction steam and fourth extraction steam respectively in accordance with a low, medium and high load. During employing the auxiliary steam and the fifth extraction steam, valves 21, 22 are controlled by the difference of pressure against a temperature regulating valve 24 or a difference between the pressure of an employing steam source and a pressure in the steam type air preheater 2. During employing the fourth extraction steam, the valve 23 is fully opened and the pressure in the preheater 2 is controlled by the temperature regulating valve 24 in a manner that the opening degree of the valve is regulated all over the load zones by the element temperature of an air preheater 3 as ever. The fore pressures of the temperature regulating valves 24 are the same, therefore, water hammer phenomenon upon switching will never be generated. |
