Advantage of oil bath heating : 1) In direct heating the heaters are directly in contact with the solvent & the temperature near the Heater tube is much higher which in turn disintegrates the solvents chemical properties. 2) As it is a known fact that we can not increase the boiling point of a particular solvent beyond its boiling point. For example if the boiling point of water is 100 degree “C” it will remain the same even if we boil it for more time It will not reach 101 degree until unless the atmospheric pressure is changed or the chemical properties are changed. Similarly if the boiling / vapor temperature of solvent is 70 degree C it will not go beyond 70 degree with the result the thermostat will Not cut the heaters if the thermostat is set for 70 degree C. with the result the heaters will be continuously on ; which will increase the electrical consumption & disintegrate The solvent due to excess heat near the heater tubes. 3) In oil bath indirect heating the temperature of the oil is raised 10-15 degree C. above the boiling point of the solvent. Once The temperature reaches the desired set point the heaters are cut off & the continues vapor is formed. Since this tank is Completely insulated the heat loss is minimum. 4) Heater life increases drastically. 5) Recyclable life of the solvent increases. 6) No scale forming due to over heating.