The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）

The general purpose of a heat exchanger is to （）.

If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.

A grease gun is generally used to lubricate a （）.

Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）

An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.

An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.

The output volume of a positive fixed displacement pump can be changed only by （）.

If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.

If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.