Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
2000-02-14
2001-11-27
Valentine, Donald R. (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S275100
Reexamination Certificate
active
06322675
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to absorption cooling units which use lithium bromide as a solution, and more specifically to an on line system for removing unwanted copper from the lithium bromide solution.
BACKGROUND OF THE INVENTION
In absorption cooling units the system uses water as a refrigerant and lithium bromide which has a high infinity for water as an absorbent. To operate efficiently, it is important that the lithium bromide solution does not become contaminated with unwanted contaminants which would aversely effect the efficiency of the system. One common problem associated with absorption systems of this type is that air tends to leak into the vacuum of the system and combines with copper components within the system such as tubing to form copper oxides. This results in the formation of ionic copper being placed into the lithium bromide solution and plating out onto metal components of the system which adversely detracts from the efficiency of the system. Copper plating and buildup is commonly found on external pumps, bearings, plugging filters, and under certain high temperature operating conditions results in the solution chemistry of the lithium bromide solution being adversely affected. This can lead a system shutdown resulting in lost time of operation, the replacement of lithium bromide solution, and in some cases replacing components parts which have been plated. Copper contents greater than about 50 parts per million are considered a problem, and in situations of this type, concentrations of copper in the range of 200 to 1000 parts per million are not uncommon.
The problem of unwanted copper being present the lithium bromide solution has been a long standing problem in the field and to date has not been solved in any satisfactory matter.
It is therefore an object of the present invention to provide an efficient copper removal system for absorption cooling units.
It is the further object of the present invention to provide an efficient on line copper removal system for absorption units.
It is yet another object of the present invention to provide an on line copper removal system for absorption units which use lithium bromide as a solution, and which allows the system to effectively operate while the copper is being removed.
It is yet a further object of the present invention to provide an efficient on line copper removal system for units using lithium bromide as a solution which can be installed simply by retrofitting an existing absorption system while it is still running.
SUMMARY OF THE INVENTION
The present invention relates to an on line copper removal system for an absorption cooling unit which operates while the unit is in operation. Specifically, the invention relates to passing a selected amount of the lithium bromide solution in the system from a flow line through a bypass which contains an electroplating unit or cell which effectively plates out the copper inside the cell. Through this system the unwanted copper which is contained in the lithium bromide solution is selectively plated out by the electroplating cell and does not deposit on the internal metal surfaces of the absorption cooling unit components as commonly occurs in conventional absorption cooling units of the prior art. The electroplating unit is typically on line outside of the internal chiller device as will be described in greater detail hereinafter. The solution is passed through a bypass flow into the copper removal cell which contains a metal anode and the copper is plated on the inside metal surfaces of the cell which acts as a cathode. The cell is powered by a low voltage DC power source. The system of the present invention can effectively reduce the copper concentration in lithium bromide solutions to below the 50 parts per million threshold which is an unacceptable level for the efficient operation of a lithium bromide solution in an absorption cooling unit.
REFERENCES:
patent: 3784455 (1974-01-01), Parikh et al.
patent: 4514270 (1985-04-01), Furutani et al.
patent: 4557811 (1985-12-01), Furst et al.
patent: 4973380 (1990-11-01), Pryor et al.
patent: 6009721 (2000-01-01), Fukuda et al.
Carrier Corporation
Valentine Donald R.
Wall Marjama & Bilinski
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