sum

difference

zero

none of these

reciprocating

rotary

linear

none of these

vertical

horizontal

inclined

none of these

equal to

lower than

higher than

none of these

control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required

empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit

increase the temperature of saturated steam without raising its pressure