单项选择题
A.drain water from the air receiver B.drain water from the cylinders C.delay the compression process until the motor is up to speed D.check pump alignment
Personnel working with refrigeration systems, and subje...
单项选择题Personnel working with refrigeration systems, and subject to the exposure of refrigerants should wear （）.
A.face shield B.a respirator C.rubber gloves D.an all purpose gas mask
To absorb the wear resulting from impeller rotation and...
单项选择题To absorb the wear resulting from impeller rotation and abrasives in the liquid, a centrifugal pump is usually fitted with （）.
A.lantern rings B.bearings C.easing volutes D.wearing rings
If the capacity of a centrifugal pump decreases gradual...
单项选择题If the capacity of a centrifugal pump decreases gradually over a long period of time, you should replace the （）.
A.packing gland B.mechanical seals C.lantern rings D.wearing rings
