单项选择题
As for an oil-fired boiler if at a normal steaming condition and water goes out of sight in gauge glasses the action you should take is: () (1) secure oil to fires (2) increase feed pump pressure
A.(1) B.(1)and(2) C.(2) D.neither(1)nor(2)
单项选择题 The amount of heat released by steam when it changes to water at the same temperature is called().
单项选择题 Latent heat changes the () of water.
单项选择题 () will be used to blow away the combustion products from the tube surfaces.