O B J E C T I V E S

Valve Basics

• Define flow and describe its function in a hydraulic system.
• Define pressure and describe its function in a hydraulic system.
• Explain the functions of valves in a hydraulic system.
• Explain the term throttling.
• Identify and describe a typical needle valve.
• Identify and describe a typical globe valve.
• Identify and describe a typical plug valve.
• Identify and describe a typical ball valve.
• Identify and describe a typical gate valve.

Actuated Valves

• Identify and describe the main components of a typical directional control, sliding spool valve.
• Explain positioning of a directional control sliding spool valve.
• Identify and describe a typical check valve.
• Identify and describe a typical relief valve.
• Identify and describe a typical pressure reducing valve.
• Define cracking pressure and pressure override.
• Describe three methods of valve actuation.
• Explain what a solenoid does, and describe two different types of solenoids.
• Describe a servo system and explain what it does.
• Describe what a pilot-operated valve is and how it works.

S U B J E C T S

Valve Basics

• Basic Principles
• Manually-Adjusted Valves

Actuated Valves

• Sliding Spool Valves
• Spring-Biased Valves
• Methods of Actuation