Method for contamination prevention in fluid storage tank requiring temperature control, and device therefor

3:

• The method according to claim 1, which includes
• allowing the cooling or heating medium to flow in the enclosed pressure-resistant jacket at the pressure lower than the pressure x (atm) by providing a pressure-reduction unit between a cooling or heating medium-storage tank opened to air and the fluid storage tank;
• suctioning the cooling or heating medium by means of a suction pump connected to an exit of the cooling or heating medium in the enclosed pressure-resistant jacket;
• transferring the cooling or heating medium from the cooling or heating medium-storage tank to the enclosed pressure-resistant jacket via the pressure-reduction unit;
• allowing the cooling or heating medium to flow and circulate through the enclosed pressure-resistant jacket;
• and
• returning the cooling or heating medium to the cooling or heating medium-storage tank via the suction pump.

4:

• The method according to claim 3, which includes
• setting a height B (m) from the bottom of the enclosed pressure-resistant jacket to the top thereof to satisfy the following equation:
• B≦C−{W(1−E)}/ρ,
• wherein
• normal pressure is deemed as 1 atm,
• C (m) is a suction height (m) of the cooling or heating medium by the suction pump,
• C=(Cmax−S)/ρ,
• Cmax (m) is a maximum suction height (m) of water by the suction pump, provided that the Cmax is a suction height when the cooling or heating medium is deemed as water,
• S(m) is a safe operational value (m) and is larger than 0 (S>0),
• ρ is a specific density of the cooling or heating medium,
• W (m) is a water-suction height (m) under vacuum,
• E (atm) is a pressure (atm) set at the pressure-reduction unit,
• E=x−d,
• x (atm) is a pressure (atm) applied to the inside of the fluid storage tank, and
• d (atm) is a difference in pressure (atm) in which a pressure (atm) at the bottom of the enclosed pressure-resistant jacket is subtracted from the pressure x (atm) within the fluid storage tank, which difference is required when the suction pump is stopped, wherein d>0.

8:

• The plant according to claim 7, which comprises
• the enclosed pressure-resistant jacket for allowing the cooling or heating medium to flow and circulate therein, said jacket being provided around the outer wall of the fluid storage tank;
• a cooling or heating medium-storage tank having a vent and connected at one end of the cooling or heating medium-storage tank to the enclosed pressure-resistant jacket via a conduit line;
• a suction pump connected at one end of the suction pump to an exit of the cooling or heating medium in the enclosed pressure-resistant jacket and connected at the other end of the suction pump to the cooling or heating medium-storage tank via a conduit line;
• and
• a pressure-reduction unit connected at one end of the pressure-reduction unit to the bottom of the enclosed pressure-resistant jacket via a conduit line and at the other end of the pressure-reduction unit to the cooling or heating medium-storage tank via a conduit line.

9:

• The plant according to claim 8, wherein a height B (m) from the bottom of the enclosed pressure-resistant jacket to the top thereof is set to satisfy the following equation:
• B≦C−{W(1−E)}/ρ,
• wherein
• normal pressure is deemed as 1 atm,
• C (m) is a suction height (m) of the cooling or heating medium by the suction pump,
• C=(Cmax−S)/ρ,
• Cmax (m) is a maximum suction height (m) of water by the suction pump, provided that the Cmax is a suction height when the cooling or heating medium is water,
• S(m) is a safe operational value (m) and is larger than 0 (S>0),
• ρ is a specific density of the cooling or heating medium,
• W (m) is a water-suction height (m) under vacuum,
• E (atm) is a pressure (atm) set at the pressure-reduction unit,
• E=x−d,
• x (atm) is a pressure (atm) applied to the inside of the fluid storage tank,
• d (atm) is a pressure difference (atm) in which a pressure (atm) at the bottom of the enclosed pressure-resistant jacket is subtracted from the pressure x (atm) within the fluid storage tank, which difference is required when the suction pump is stopped, wherein d>0, and
• whereby the cooling or heating medium is allowed to flow in the enclosed pressure-resistant jacket at a pressure lower than the pressure x (atm) and each of the enclosed pressure-resistant jackets is maintained at the pressure lower than the pressure x (atm).

12:

• A plant in which contamination of a fluid in a fluid storage tank under a predetermined pressure with a liquid cooling or heating medium owing to breakage of a wall of the fluid storage tank is prevented, wherein a temperature of the fluid in said fluid storage tank is controlled by allowing the cooling or heating medium to flow through an enclosed pressure-resistant jacket provided around an outer wall of the fluid storage tank, which comprises
• a cooling or heating medium-storage tank opened to the air or a cooling or heating medium-supplying server tank opened to the air;
• and
• a control system that allows the cooling or heating medium supplied from the cooling or heating medium-storage tank opened to the air or from the cooling or heating medium-supplying server tank opened to the air to flow in the enclosed pressure-resistant jacket at a pressure lower than a predetermined pressure x (atm) within the fluid storage tank.

13:

• The plant according to claim 12, wherein
• the fluid storage tank is a larger size tank having a height B (m) exceeding a suction height C (m) of the cooling or heating medium by a suction pump,
• the enclosed pressure-resistant jacket has a multistage construction with not less than two staged enclosed pressure-resistant jackets,
• each of the multiple staged enclosed pressure-resistant jackets is provided with a pressure reduction unit, and
• said pressure reduction unit is arranged between the cooling or heating medium-storage tank and the bottom of each enclosed pressure-resistant jackets.

14:

• The plant according to claim 13, wherein a height B′ from the bottom of each of the enclosed pressure-resistant jackets to the top thereof is set to satisfy the following equation:
• B′≦C−{W(1−E)}/ρ
• wherein, C=(Cmax−S)/ρ,
• Cmax (m) is a maximum suction height (m) of water by the suction pump, provided that the Cmax is a suction height when the cooling or heating medium is water,
• S(m) is a safe operational value (m) and is larger than 0 (S>0),
• ρ is as defined above),
• W (m) is a water-suction height (m) under vacuum, and
• E (atm) is a pressure (atm) set at the pressure-reduction unit).

16:

• A method for detecting cracks of a fluid storage tank in which a temperature of a fluid in said fluid storage tank is controlled by allowing a liquid cooling or heating medium supplied from a cooling or heating medium-storage tank or a cooling or heating medium-supplying server tank provided separately from the fluid storage tank to flow in an enclosed pressure-resistant jacket provided around an outer wall of the fluid storage tank, which method comprises:
• allowing the liquid cooling or heating medium to flow in the enclosed pressure-resistant jacket at a pressure lower than a pressure x (atm) applied within the fluid storage tank;
• maintaining the pressure in the pressure-resistant jacket lower than the pressure x;
• sampling the cooling or heating medium from an air pool provided in a passage of the cooling or heating medium;
• and
• analyzing the components of the cooling or heating medium, while preventing contamination of the fluid in the fluid storage tank with the liquid cooling or heating medium.

18:

• A method of controlling pressure in an enclosed pressure-resistant jacket provided around an outer wall of the fluid storage tank, wherein the contamination is caused by damage of a wall of a fluid storage tank containing fluid therein, the method comprising:
• setting a height B (m) from the bottom of the enclosed pressure-resistant jacket to the top thereof is set to satisfy the following equation:
• B≦C−{W(1−E)}/ρ;
• wherein, normal pressure is deemed as 1 atm,
• C (m) is a suction height (m) of the cooling or heating medium by the suction pump and C=(Cmax−S)/ρ,
• Cmax (m) is a maximum suction height (m) of water by the suction pump, provided that the Cmax is a suction height when the cooling or heating medium is water,
• S(m) is a safe operational value (m) and is larger than 0 (S>0),
• ρ is a specific density of the cooling or heating medium,
• W (m) is a water-suction height (m) under vacuum,
• E (atm) is a pressure (atm) set at the pressure-reduction unit,
• E=x−d,
• x (atm) is a pressure (atm) applied to the inside of the fluid storage tank,
• d (atm) is a difference in pressure (atm) in which a pressure (atm) at the bottom of the enclosed pressure-resistant jacket is subtracted from the pressure x (atm) within the fluid storage tank, which difference is required when the suction pump is stopped, wherein d>0.