Blakeslee 05542

PILOT SCREW

A pilot light is a small gas flame, usually natural gas or liquefied petroleum gas, which serves as an ignition source for a more powerful gas burner. In a pilot assembly, there is thermocouple sitting in the pilot light's flame. The electricity that is created from the flame contacting the thermocouple wire runs to a small electromagnetic valve and holds it open. If the pilot light blows out, the thermocouple quickly cools off. It stops generating electricity and the valve closes.

A screw is a type of fastener, in some ways similar to a bolt typically made of metal, and characterized by a helical ridge, known as a male thread (external thread). Screws are used to fasten materials by digging in and wedging into a material when turned, while the thread cuts grooves in the fastened material that may help pull fastened materials together and prevent pull-out.

A screw drive is a system used to turn a screw. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. Other examples include Phillips head screws and screwdrivers, and Allen hex screws and wrenches.