Belonging to the positive displacement pump is ( ).

A pump commonly used for transporting strong corrosive media in refining chemical units is ( ).

The centrifugal pump mainly relies on the high-speed rotation of the impeller to produce ( ) increased liquid pressure and radial discharge of the impeller.

Belonging to the vane type pump is ( ).

Before starting the pump, the one that must be pumped first is ( ).

Pumps are indispensable ( ) machinery in refining and chemical plants.

Refining chemical units are commonly used to transport liquids with low viscosity and high flow rate pumps are ( ).

Centrifugal pumps are suitable for ( ) liquids.

Other conditions being equal, liquid viscosity increases, centrifugal pump head ( ).

When the centrifugal pump is running, other conditions remain unchanged and the flow rate increases, the motor current ( ).

Other conditions being equal, liquid viscosity increases, centrifugal pump efficiency ( ).

Other conditions remain the same, the liquid viscosity increases, then the centrifugal pump shaft power ( ).

A general heat exchanger for high temperature and pressure is ( ).

Of the following options, which belong to the new high efficiency heat exchanger is ( ).

The following heat exchangers that do not transfer heat through the tube wall are ( ).