Apparatus for industrial and commercial food preparation by boiling, cooking, smoking, steaming, roasting, baking and chilling, namely, cooking ovens, boiling vats, steam cookers and refrigerators; exhaust air purification units; ventilating fans for commercial and industrial use; waste water purification units; steam generator; electric pressure cooker; electric cooker; industrial refrigerator; desiccating units for producing dried meats, fish and poultry; food smoking chamber; smoke generat...