Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.

On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.

Thermostatic expansion valves can be adjusted for （）.

The major source of chemical contaminants in hydraulic fluid is （）.

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

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

The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.

When the steering gear is in operation, you should （）.

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

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