\pgfkeys{
        /valve/dimension/width/.code = {{#1}},
        /valve/dimension/width/.initial = {0.5 cm},
        /valve/.is choice,
        /valve/basic/.code = {
            \pgfkeys{/valve/draw/.append code = {
            \east
            \pgf@xa = \pgf@x

            \pgfpathmoveto{\centerpoint}
            \pgfpathlineto{\pgfpoint{\pgf@xa}{-0.5\pgf@xa}}
            \pgfpathlineto{\pgfpoint{\pgf@xa}{0.5\pgf@xa}}
            \pgfpathclose
            
            \pgfusepath{stroke}
            }
        }},
        /valve/angle/.code = {
            \pgfkeys{/valve/draw/.append code = {
            \east
            \pgf@xa = \pgf@x

            \pgfpathmoveto{\centerpoint}
            \pgfpathlineto{\pgfpoint{-0.5 \pgf@xa}{-\pgf@xa}}
            \pgfpathlineto{\pgfpoint{0.5 \pgf@xa}{-\pgf@xa}}
            \pgfpathclose
            
            \pgfusepath{stroke}
            }
        }},
        /valve/three way/.code = {
            \pgfkeys{/valve/basic}
            \pgfkeys{/valve/angle}
        },
        /valve/globe/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.25}{\east}
                \pgf@xa = \pgf@x

                \pgfpathcircle{\centerpoint}{\pgf@xa}
                \pgfusepath{fill, stroke}
            }
        }},
        /valve/ball/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfsetfillcolor{white}
                \pgfpointscale{0.25}{\east}
                \pgf@xa = \pgf@x

                \pgfpathcircle{\centerpoint}{\pgf@xa}
                \pgfusepath{fill, stroke}
                \pgfsetfillcolor{black}
            }
        }},
        /valve/gate/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.5}{\east}
                \pgf@xa = \pgf@x

                \pgfpathmoveto{\pgfpoint{0}{-\pgf@xa}}
                \pgfpathlineto{\pgfpoint{0}{\pgf@xa}}
                \pgfusepath{stroke}
            }
        }},
        /valve/butterfly/.code = {
            \pgfkeys{/valve/globe}
            \pgfkeys{/valve/gate}
        },
        /valve/needle/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.1}{\east}
                \pgf@xa = \pgf@x

                \pgfpointscale{0.5}{\east}
                \pgf@ya = \pgf@x

                \pgfpathmoveto{\centerpoint}
                \pgfpathlineto{\pgfpoint{-\pgf@xa}{\pgf@ya}}
                \pgfpathlineto{\pgfpoint{\pgf@xa}{\pgf@ya}}
                \pgfpathclose
                \pgfusepath{fill, stroke}
            }
        }},
        /valve/continuous/.code = {
            \pgfkeys{/valve/basic}
            \pgfkeys{/valve/draw/.append code = {
                \east
                \pgf@xa = \pgf@x

                \pgfpathmoveto{\pgfpoint{-1.6 \pgf@xa}{-0.8 \pgf@xa}}
                \pgfpathlineto{\pgfpoint{1.6 \pgf@xa}{0.8  \pgf@xa}}
                \pgfsetarrowsend{Latex[length=4pt, width = 2pt]}
                \pgfusepath{stroke}
            }
        }},
        /valve/check/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.25}{\east}
                \pgf@xa = \pgf@x

                \east
                \pgf@xb = \pgf@x

                \pgfpathcircle{\pgfpoint{-\pgf@xb}{0.5 \pgf@xb}}{\pgf@xa}

                \pgfusepath{fill, stroke}
            }
        }},
        /valve/spring loaded/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.4}{\east}
                \pgf@xa = \pgf@x

                \pgfpathmoveto{\centerpoint}
                \pgfpathlineto{\pgfpoint{0}{\pgf@xa}}
            
                \pgfpathlineto{\pgfpoint{-\pgf@xa}{1.5 \pgf@xa}}
                \pgfpathlineto{\pgfpoint{\pgf@xa}{2.5 \pgf@xa}}
                \pgfpathlineto{\pgfpoint{-\pgf@xa}{3.5 \pgf@xa}}
                \pgfpathlineto{\pgfpoint{\pgf@xa}{4.5 \pgf@xa}}

                \pgfpathlineto{\pgfpoint{0}{5 \pgf@xa}}
                \pgfpathlineto{\pgfpoint{0}{5.5 \pgf@xa}}

                \pgfusepath{stroke}
            }
        }},
        /valve/safety/.code = {
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.5}{\east}
                \pgf@xa = \pgf@x
                
                \pgfsetlinewidth{4 \pgflinewidth}
                \pgfpathmoveto{\pgfpoint{-\pgf@xa}{-\pgf@xa}}
                \pgfpathlineto{\pgfpoint{-\pgf@xa}{\pgf@xa}}

                \pgfusepath{stroke}
                \pgfsetlinewidth{0.25 \pgflinewidth}
            }
        }},
        /valve/breather/.code = {
            \pgfkeys{/valve/basic}
            \pgfkeys{/valve/draw/.append code = {
                \pgfpointscale{0.25}{\east}
                \pgf@xa = \pgf@x

                \east
                \pgf@xb = \pgf@x

                \pgfpathcircle{\pgfpoint{-\pgf@xb}{0.5 \pgf@xb}}{\pgf@xa}

                \pgfpointscale{0.25}{\east}
                \pgf@xa = \pgf@x

                \east
                \pgf@xb = \pgf@x

                \pgfpathcircle{\pgfpoint{\pgf@xb}{-0.5 \pgf@xb}}{\pgf@xa}

                \pgfusepath{fill, stroke}
            }
        }},
        /valve/draw/.code = {},
        /valve/.default = {\pgfkeys{/valve/basic}}
}

\pgfdeclareshape{valve}{
    \savedanchor{\centerpoint}{
        \pgfpointorigin
    }
    \savedanchor{\east}{
        \pgfpoint{\pgfkeysvalueof{/valve/dimension/width}}{0}
        \pgfpointscale{0.5}{\pgfpoint{\pgf@x}{\pgf@y}}
    }
    
    \anchor{center}{
        \centerpoint
    }
    \anchor{east}{
        \east
    }
    \anchor{west}{
        \east
        \pgfpoint{-\pgf@x}{\pgf@y}
    }
    \anchor{near north}{
        \east
        \pgf@xa = 0.25\pgf@x
        \pgfpoint{0}{\pgf@xa}
    }
    \anchor{north}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{0}{\pgf@xa}
    }
    \anchor{far north}{
        \east
        \pgf@xa = \pgf@x
        \pgfpoint{0}{\pgf@xa}
    }
    \anchor{near south}{
        \east
        \pgf@xa = 0.25\pgf@x
        \pgfpoint{0}{-\pgf@xa}
    }
    \anchor{south}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{0}{-\pgf@xa}
    }
    \anchor{far south}{
        \east
        \pgf@xa = \pgf@x
        \pgfpoint{0}{-\pgf@xa}
    }
    \anchor{northeast}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{\pgf@x}{\pgf@xa}
    }
    \anchor{northwest}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{-\pgf@x}{\pgf@xa}
    }
    \anchor{southeast}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{\pgf@x}{-\pgf@xa}
    }
    \anchor{southwest}{
        \east
        \pgf@xa = 0.5\pgf@x
        \pgfpoint{-\pgf@x}{-\pgf@xa}
    }
    
    \backgroundpath{
        \east
        \pgf@xa = \pgf@x

        \pgfpathmoveto{\pgfpointorigin}

        \pgfpathlineto{\pgfpoint{-\pgf@xa}{-0.5\pgf@xa}}
        \pgfpathlineto{\pgfpoint{-\pgf@xa}{0.5\pgf@xa}}
        \pgfpathclose
        
        \pgfusepath{stroke}
        
        \pgfkeys{/valve/draw}
    }
}