Which type of lubrication pump is a cylinder and plunger type?

The correct answer is the barrel pump, which operates on the principle of a cylinder and plunger mechanism. In this type of pump, the plunger moves within the cylinder to create a change in pressure that facilitates the movement of lubricant. The design allows for efficient delivery of lubricant in a controlled manner, making it suitable for various applications where consistent lubrication is crucial.

Barrel pumps are often utilized in scenarios requiring a fixed discharge and can handle thicker lubricants. This setup is particularly valuable in small engine applications where precise lubrication can significantly impact performance and longevity.

The other types of pumps listed have different operating principles. Gear pumps use meshing gears to transfer fluid, diaphragm pumps utilize a flexible diaphragm to create a pumping action, and piston pumps rely on a reciprocating piston to move fluid. Each of these designs serves particular needs but does not specifically use a cylinder and plunger mechanism like the barrel pump does.