Block And Bleed Valve Symbol

bleed valve
Used to manually turn on an automatic valve. a bleed valve is located on or near the top of the valve. It can be a small screw, a lever, or built into the solenoid. When turned, the bleed valve allows water to flow out of the cavity over the internal diaphragm of the valve.
a valve that releases air from the central heating system.

symbol
A mark or character used as a conventional representation of an object, function, or process, e.g., the letter or letters standing for a chemical element or a character in musical notation
an arbitrary sign (written or printed) that has acquired a conventional significance
something visible that by association or convention represents something else that is invisible; "the eagle is a symbol of the United States"
A thing that represents or stands for something else, esp. a material object representing something abstract
A shape or sign used to represent something such as an organization, e.g., a red cross or a Star of David
The typographic character @, called the at sign or at symbol, is an abbreviation of the word at or the phrase at the rate of in accounting and commercial invoices (e.g. "7 widgets @ $2 = $14"). Its most common modern use is in e-mail addresses, where it stands for "located at".

block
A large solid piece of hard material, esp. rock, stone, or wood, typically with flat surfaces on each side
A sturdy, flat-topped block used as a work surface, typically for chopping food
Any of a set of solid cubes used as a child's toy
barricade: render unsuitable for passage; "block the way"; "barricade the streets"; "stop the busy road"
a solid piece of something (usually having flat rectangular sides); "the pyramids were built with large stone blocks"
a rectangular area in a city surrounded by streets and usually containing several buildings; "he lives in the next block"