(The VERTICAL_VESSEL is composed of 
element SKIRT with 
	geometry = cylinder
	diameter = equipment.diameter
	length = equipment.skirt_height OR (equipment.length / 4.0)
	element VESSEL with
	geometry = cylinder
	diameter = equipment.diameter 
	length = equipment.length
	local-z-origin = skirt.length
element TOP-HEAD with
	geometry = elliptical-head
	radius = 0.5 * diameter
	height = equipment.head_height OR (0.05 * diameter)
	local-z-origin = vessel.local-z-origin + 		vessel.length
element LABEL with
	geometry = text
	width = 0.8 * diameter
	string = display_name
	rotation = east-west
	local-y-origin = 0.11 * diameter
	local-z-origin = 1.1 * length
element OBSTACLE with 
	type = obstacle 
	geometry = box
	x-dimension = diameter
	y-dimension = diameter
	z-dimension = vessel.length + top-head.height
	local-x-origin = diameter / -2.0
	local-y-origin = diameter / -2.0
	local-z-origin = skirt.length)