A pure liquid manufacturing apparatus, comprising:
- a heating unit that heats a supplied liquid by heat exchange with a predetermined high temperature heat source to prepare a liquid and/or vapor having a predetermined temperature;
- a vaporization unit operatively connected to the heating unit, the vaporization unit configured to receive the liquid and/or vapor from said heating unit and to vaporize at least said liquid in a decompression space;
- a separation unit operatively connected to the vaporization unit, the separation unit configured to collect liquid of the liquid and/or vapor supplied from said vaporization unit to remove the liquid from the liquid and/or vapor;
- a condensation unit operatively connected to the separation unit, the condensation unit configured to cause the vapor received from said separation unit to be subject to heat exchange with a predetermined cooling liquid to condense it to obtain pure liquid;
- a drain tank unit operatively connected to the vaporization unit and to the separation unit, the drain tank configured to collect a remaining liquid, which has not been vaporized by said vaporization unit, and the liquid, which has been removed by said separation unit, to temporarily store the remaining liquid and the liquid which has been removed by said separation unit;
- and
- a pump unit operatively connected to the heating unit and to the drain tank, the pump unit configured to pressurize the liquid in said drain tank unit to supply it to said heating unit,
- wherein:
- a fresh liquid is newly supplied from a predetermined liquid supply source to said drain tank unit such that the drain tank unit contains a mixed liquid, said fresh liquid as newly supplied, the remaining liquid from said vaporization unit, and the liquid which has been removed by said separation unit in a mixed state, the drain tank unit configured to supply the mixed liquid through the pump unit to said heating unit;
- and
- a liquid supply tank unit that is provided between said liquid supply source and the drain tank unit to temporarily store the fresh liquid as newly supplied from the liquid supply source and supply it to a side of the drain tank unit;
- and
- wherein:
- said drain tank unit is provided with a sensor unit that measures an electric conductivity of the mixed liquid of said fresh liquid as newly supplied and the liquid from said vaporization unit and said separation unit in the mixed state, and
- the drain tank unit, when the electric conductivity of said liquid in the mixed state in said drain tank unit, as measured by the sensor, exceeds a predetermined upper limit value, is configured to flow out a part of the liquid in the mixed state into said liquid supply tank unit.