Symbols of chemical apparatus and instrumentation Pipe Thermally insulated_pip e Jacketed_pip e Cooled_or_heated_pip e Jacketed mixing vessel (autoclave ) Half pipe mixing vessel Pressurized horizontal vessel Pressurized vertical vessel Pump Vacuum pump or compressor Bag Gas bottle per gas Fan Axial fan Radial fan Dryer Packing column Tray columnFurnace Cooling tower Heat exchanger Heat exchanger Cooler Plate & frame heat exchanger