单项选择题

The most common contaminate of governor hydraulic fluid is （）.

A.moisture
B.dirt
C.acid
D.air

<上一题目录下一题>

热门试题

单项选择题

The purpose of the safety relief valves installed on an auxiliary boiler is to （）.

A.relieve excess fuel oil pressure during the “off” fire cycle
B.admit water to the dry pipe
C.throttle the forced draft fan output for proper combustion
D.reduce excess steam pressure in the boiler

单项选择题

The pH value of water in a diesel engine closed cooling water system should be maintained between （）.

A.60 to75
B.80 to 95
C.100 to 115
D.120 to 135