Refrigeration Plant Operator B Practice Test

What type of pump discharges fluid as its piston or plunger moves in one direction?

1. dynamic pump

2. single-acting pump

3. double-acting pump

4. reciprocating pump

The correct answer is: single-acting pump

A single-acting pump is specifically designed to discharge fluid during the movement of its piston or plunger in one direction. In this design, the fluid is drawn into the cylinder on the return stroke and then expelled during the forward stroke, with the discharge occurring only during that single direction of motion. This makes it distinctive from other types of pumps where the mechanism may allow for both forward and backward movement to impact fluid discharge. Dynamic pumps, on the other hand, function primarily through kinetic energy and are not reliant on a plunger or piston for the movement of fluid. Double-acting pumps have the capability to discharge fluid during both directions of the piston movement, which means they operate quite differently from single-acting pumps. Reciprocating pumps encompass a broader category that includes both single and double-acting types but does not specify the one-directional action that characterizes a single-acting pump. Hence, the feature of discharging fluid only in one direction confirms why a single-acting pump is the correct response.