These are meant for dosing various chemicals, like poly-electrolytes, stabilizers, enzymes, acids etc., in different chemical process industries at precise flow rates. Dosing can be done into pressurized or non-pressurized vessels and design will be done accordingly.
These dosing skids normally consist of dosing pumps, flow meters, level switches, flow transmitters, pressure switch / transmitters, back pressure valves, safety relief valves, control panels etc.
Typical dosing units are phosphoric acid and caustic dosing skids in vegetable refineries.