Valves

What are valves?
How do valves work?
What are the different types of valves?
What are the different applications for valves?
What is the difference between manual and automatic valves?
What are the common problems with valves?
What safety precautions should I take when installing a valve?
What are gate valves?
What are globe valves?
What are ball valves?
What are butterfly valves?
What are check valves?
What are diaphragm valves?
What are pinch valves?
What are needle valves?