Heat exchanger for connection to an evaporator of a heat transfer system
View Patent ↗A heat transfer system having an evaporator, a heat exchanger, and a working fluid that undergoes compression. The heat exchanger includes a first tube made from a steel alloy which is alloyed to facilitate bending, the first tube having a first end connected to the outlet of an evaporator and a second tube having a first end connected to the inlet of the evaporator. The second tube is positioned in thermal contact with the first tube for a portion of the respective lengths of the first tube and the second tube, so as to allow an exchange of heat between the fluid within the tubes.
1. A heat transfer system comprising working fluid that undergoes compression and evaporation, an evaporator having an inlet and an outlet, and a heat exchanger, said heat exchanger comprising: a first tube having a first end connected to said outlet of the evaporator to allow transmission of said working fluid from said outlet; and, a second tube having a first end connected to said inlet of the evaporator to allow transmission of said working fluid to said inlet, wherein a portion of the length of the first tube is positioned in thermal contact with a portion of the length of the second tube so as to allow an exchange of heat between the working fluid in said first tube and the working fluid in said second tube; said first tube is constructed from a steel alloy having a carbon content of less than 0.03% by mass and a titanium content of between 0.05% and 0.4% by mass, thereby reducing the hardness of the steel alloy to facilitate bending of the first tube during installation within the heat transfer system.
2. The heat transfer system according to claim 1 , wherein said first end of said first tube and said first end of said second tube extend separately from each other to allow respective connections to said outlet and said inlet of said evaporator.
3. The heat transfer system according to claim 1 , wherein the second tube is a capillary tube for transmission of fluid to the evaporator.
4. The heat transfer system according to claim 3 , wherein said second tube comprises a capillary tube for transporting liquid to the evaporator of the heat transfer system, and said first tube comprises a suction tube for transporting fluid from the evaporator,
wherein a portion of said length of the capillary tube is secured to a portion of the length of said suction tube such that thermal conduction is provided from the liquid in said capillary tube to the fluid in said suction tube, and,
wherein said suction tube comprises a steel alloy tube, and at least said portion of said suction tube is coated with a protective coating providing a surface onto which said capillary tube is soldered or brazed.
5. The heat transfer system according to claim 4 , wherein said protective coating comprises zinc.
6. The heat transfer system according to claim 4 , wherein said protective coating on said suction tube is produced by hot dip zinc coating.
7. The heat transfer system according to claim 4 , wherein said capillary tube is a copper tube.
8. The heat transfer system according to claim 1 , wherein the steel alloy of said first tube has a titanium content between 0.06% and 0.3% by mass.
9. The heat transfer system according to claim 1 , wherein the steel alloy of said first tube has a percentage titanium content by mass which is greater than four times the percentage carbon content by mass of the steel alloy.
10. The heat transfer system according to claim 1 , wherein said first tube comprises steel having a manganese content of less than 0.35% by mass, a phosphorus content of less than 0.03% by mass, and a sulphur content of less than 0.03% by mass.
11. The heat transfer system according to claim 10 , wherein said first tube comprises steel having a carbon content of up to 0.02% by mass, a manganese content of up to 0.25% by mass, a phosphorus content of up to 0.02% by mass and a sulphur content of up to 0.02% by mass.
12. The heat transfer system according to claim 1 , wherein said first tube has a seam weld.
13. The heat transfer system according to claim 1 , wherein said first tube has a protective metallic coating which resists corrosion of the steel alloy.
14. The heat transfer system according to claim 13 , wherein said first tube is aluminium plated.
15. The heat exchanger according to claim 13 , wherein said first tube has a zinc coating.
16. The heat transfer system according to claim 13 , wherein said heat exchanger further comprises solder or braze and said portion of the length of the second tube is attached to the protective coating of the first tube by said solder or braze.
17. The heat transfer system according to claim 1 , wherein said heat exchanger further comprises solder or braze attaching the second tube to the first tube.
18. The heat transfer system according to claim 17 , wherein the second tube is attached to the first tube using solder comprising of tin alloy.
19. The heat exchanger according to claim 1 , wherein the second tube is attached to the first tube using a heat shrinkable tube.
20. The heat exchanger according to claim 1 , wherein said portion of the length of the second tube is located within the bore of the first tube.
21. The heat transfer system according to claim 1 , wherein said steel alloy is in an annealed state in order to further reduce its hardness.