177) The number of water level indicators in a boiler are generally __________ in number.

178) The fire tubes in a Locomotive boiler has __________ diameter.

179) A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly

180) Fire tube boilers are limited to a maximum working pressure of

181) The average value of diagram factor lies between