为了防止因积灰而造成堵塞,焦炉斜道的倾斜角应小于()度。
A. 20
B. 30
C. 40
D. 50
为提高炉头温度,进入炉头的空气过剩系数应为()
A. 1.25
B. 1.15
C. 1.3以上
D. 1.15以下
()aremountedinpairstoprotecttheboileragainstoverpressure.
A. Safetyvalves
B. Watertubes
C. Steamstopvalves
D. Blowdownvalves
Chainslingsaresuitableforheavyslenderarticles,suchas().
A. timberorsteelrails
B. locomotivesorboilers
C. railwaypassengercoaches
D. motorvehicles