Hydraulic fluids lubricate moving parts of a circuit.

Strainer screens are rated in microns and filters are rated in mesh.

A flared fitting is a fitting that is connected to tubing with an end that is spread outward.

The higher the mesh number of a strainer, the smaller the opening.

Tubing may be connected by welding or compression.

Positive displacement is the movement of a fixed volume of fluid with each revolution of a hydraulic pump.

A spur gear has straight teeth that are parallel to the shaft axes in a gear pump.

A pressure-relief valve is a valve that sets a maximum operating pressure level for a circuit to protect the circuit from overpressure.

Vane pumps are the most widely used hydraulic pumps because of their simple design and ease of repair.