Which type of blower or compressor produces axial flow?

The correct answer is based on the specific mechanism and design of the equipment that facilitates the movement of air or gas. A screw compressor operates by using two interlocking screws that rotate in opposite directions, which effectively draws in the gas axially and compresses it. This type of compressor is designed to move the air or gas parallel to the axis of rotation, creating axial flow.

Axial flow is characterized by the direction of the fluid moving in line with the rotational axis of the machinery. In the case of the screw compressor, the gas is drawn in from one end and expelled through the other end in a continuous flow, which is essential for many industrial applications where consistent and efficient compression is required.

Other types of equipment listed, such as centrifugal blowers, piston compressors, and diaphragm pumps, operate using different principles that do not achieve axial flow in the same manner. Centrifugal blowers use a rotating impeller to impart radial velocity to the air, while piston compressors utilize a reciprocating motion to compress the gas. Diaphragm pumps generate flow by employing a flexible diaphragm that moves the fluid, typically creating displacement rather than direct axial flow. Understanding these mechanisms clarifies why the screw compressor is uniquely identified with axial flow among the options provided.