Evaporative cooling method by natural circulation of cooling water

Claim 2

Evaporative cooling method by natural circulation of cooling water comprising the steps of using an evaporative cooling device comprising a cooling pipe fitted to an object to be cooled and a steam separator drum arranged above said cooling pipe, said cooling pipe and said steam separator drum being connected together by a downcomer and a riser, separating steam generated within the circuit of said evaporative cooling device from cooling water by means of said steam separator drum, discharging said steam to outside the circuit, totally replenishing cooling water from outside the circuit to the middle of said downcomer in an amount corresponding to the quantity of the discharged steam, keeping the cooling water in said cooling pipe in complete liquid state and causing part of cooling water to evaporate only in said riser and in said stream separator drum by setting parameters to satisfy the following formula: Q/V.sup. .ρ . c< ΔT.sub.eq (P.sub.o Ph.sub.3) Where, Q:Thermal load acting on said cooling pipe V:Amount of circulated cooling water in said cooling pipe ρ:Density of cooling water c:Specific heat of cooling water P o :Pressure in said steam separator drum Ph 3 :Pressure of cooling water in uppermost part of said cooling pipe Δ T eq (P.sub. o, Ph 3 ):Boiling equilibrium temperature difference between P o and Ph 3 .

Claim 3

The method of claim 1, wherein said cooling pipes are used in the number of at least two, characterized by providing a flow rate regulating valve for cooling water at the inlet of each of said cooling pipes, providing an outlet thermometer for cooling water at the outlet of each of said cooling pipes, measuring the temperature of cooling water at the outlet of each of said cooling pipes, and regulating the flow rates of cooling water in each of said cooling pipe with said flow rate regulating valve so that the temperatures of cooling water at the outlets of said cooling pipes are substantially equal.

Claim 4

Evaporative cooling method by natural circulation of cooling water comprising the steps of using an evaporative cooling device comprising a cooling pipe fitted to an object to be cooled and a steam separator drum arranged above said cooling pipe, said cooling pipe and said steam separator drum being connected together by a downcomer and a riser, separating steam generated within the circuit of said evaporative cooling device from cooling water by means of said steam separator drum, discharging said steam to outside the circuit, replenishing cooling water from outside the circuit by distributing said cooling water to both said steam separator drum and the middle of said downcomer, the cooling water being replenished in a total amount corresponding to the quantity of the discharged steam, keeping the cooling water in said cooling pipe in complete liquid state and causing part of cooling water to evaporate only in said riser and in said steam separator drum by setting parameters to satisfy the following formula: Q/V.sup. .ρ . c< ΔT.sub.eq (P.sub.o, Ph.sub.3) Where, Q:Thermal load acting on said cooling pipe V:Amount of circulated cooling water in said cooling pipe ρ:Density of cooling water c:Specific heat of cooling water P o :Pressure in said steam separator drum Ph 3 :Pressure of cooling water in uppermost part of said cooling pipe Δ T eq (P P o , Ph 3 ):Boiling equilibrium temperature difference between P o and Ph 3 .

Claim 5

Evaporative cooling method by natural circulation of cooling water comprising the steps of using an evaporative cooling device comprising a cooling pipe fitted to an object to be cooled and a steam separator drum arranged above said cooling pipe, said cooling pipe and said steam separator drum being connected together by a downcomer and a riser, separating steam generated within the circuit of said evaporative cooling device from cooling water by means of said steam separator drum, discharging said steam to outside the circuit, replenishing cooling water from outside the circuit by distributing said cooling water to both said steam separator drum and the middle of said downcomer, the cooling water being replenished in a total amount corresponding to the quantity of the discharged steam, keeping the cooling water in said cooling pipe in complete liquid state and causing part of cooling water to evaporate only in said riser and in said steam separator drum by setting parameters to satisfy the following formula: Q/V.sup. .ρ . c< ΔT.sub.eq (P.sub.o, Ph.sub.3) Where, Q:Thermal load acting on said cooling pipe V:Amount of circulated cooling water in said cooling pipe ρ:Density of cooling water c:Specific heat of cooling water P o :Pressure in said steam separator drum Ph 3 :Pressure of cooling water in uppermost part of said cooling pipe Δ T eq (P P o , Ph 3 ):Boiling equilibrium temperature difference between P o and Ph 3 .

Claim 6

The method of claim 3, wherein said cooling pipes are used in the number of at least two, characterized by providing a flow rate regulating valve for cooling water at the inlet of each of said cooling pipes, providing an outlet thermometer for cooling water at the outlet of each of said cooling pipes, measuring the temperature of cooling water at the outlet of each of said cooling pipes, and regulating the flow rates of cooling water in each of said cooling pipe with said flow rate regulating valve so that the temperatures of cooling water at the outlets of said cooling pipes are substantially equal.

Claim 7

The method of claim 3, wherein the evaporation of cooling water is measured at two predetermined points in said riser for the regulation of the amounts of water replenished to both said steam separator drum and the middle of said downcomer according to said measured values.

Claim 8

The method of claim 3, wherein the level of cooling water in said steam separator drum is measured for the regulation of the amounts of water replenished to both said steam separator drum and the middle of said downcomer according to said measured values so that said level of cooling water in said steam separator drum always corresponds to a predetermined water level.

Claim 9

The method of claim 5, wherein said cooling pipes are used in the number of at least two, characterized by providing a flow rate regulating valve for cooling water at the inlet of each of said cooling pipes, providing an outlet thermometer for cooling water at the outlet of each of said cooling pipes, measuring the temperature of cooling water at the outlet of each of said cooling pipes, and regulating the flow rates of cooling water in each of said cooling pipe with said flow rate regulating valve so that the temperatures of cooling water at the outlets of said cooling pipes are substantially equal.

Claim 10

The method of claim 6, wherein said cooling pipes are used in the number of at least two, characterized by providing a flow rate regulating valve for cooling water at the inlet of each of said cooling pipes, providing an outlet thermometer for cooling water at the outlet of each of said cooling pipes, measuring the temperature of cooling water at the outlet of each of said cooling pipes, and regulating the flow rates of cooling water in each of said cooling pipe with said flow rate regulating valve so that the temperatures of cooling water at the outlets of said cooling pipes are substantially equal.