單項(xiàng)選擇題

The purpose of the wearing rings used in a centrifugal pump is to （）.

A.prevent an internal explosion in the pump when it is overheated
B.enable a visual inspection of the pump while it is running
C.insure a proper alignment of the pump coupling to the driver
D.accommodate for friction between the impeller and the easing

你可能感興趣的試題

單項(xiàng)選擇題

The lowest temperature required to cause self-sustained combustion of a substance independent of any outside source of ignition is called （）.

A.explosive range
B.flash point
C.ignition temperature
D.combustion temperature

單項(xiàng)選擇題

If a refrigeration compressor will not start, the reason may be （）.

A.the pressure regulating valve is not closing
B.an excessive lack of refrigerant in the system
C.badly leaking discharge valves
D.worn piston rings