US2666000A - Process for cleaning automobile radiators - Google Patents

Description

and tetrasodium pyrophosphate.

Patented Jan. 12, 1954 PROCESS FOR CLEANING AUTOMOBILE RADIATORS Hugh C. De Hoff, Roselle Park, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application October 11, 1950, Serial No. 189,685

1 Claim. 1

This invention concerns a novel composition of matter suitable for use as a cleaning agent for the radiators of automotive type engines. The composition of this invention comprises a combination of approximately equal parts of oxalic acid and ammonium oxalate, preferably inEornnation with a detergent. This cleaning composition is to be employed in a radiator as an aqueous solution to remove iron rust. after which a neutralizing composition is preferably employed which comprises a mixture of sodium carbonate The use of the indicated cleaning composition is effective in cleaning the radiator of engines to an extent heretofore unobtainable when employing conventional radiator cleaners.

At the present time the radiator of an automotive type engine is principally constructed of ferrous material. However, soldered joints in the radiator, to ether with connecting lines, are generally of such a nature that copper is also present, either in the radiator or in lines associated with the radiator. In the course of time, the interstices of the radiator become rusted so as to necessitate some means for removing the iron rust which has formed. Consequently, it is necessary to provide a cleaning agent capable of dissolving or removing iron rust in the radiator. At the same time it is necessary to minimize or eliminate the attack of this cleaning agent on copper compositions present in the radiator. It is therefore the object of this invention to provide a novel cleaning composition and technique capable of achieving these objectives.

It had been found that a cleaning composition consisting of a mixture of oxalic acid and am-- monium oxalate is peculiarly effective in removing iron rust from a radiator. It is particularly notable that. in some manner. these two compounds appear to exert a cooperative action so as to provide cleaning results not obtainable with equivalent amounts of either of the compounds individually. Thus, the combination of oxalic acid and am onium oxalate is effective to remove greater quantities of iron rust from a radiator than either of these compounds alone when employing similar quantities.

Use of an acidic cleaning compound of the nature indicated, necessitates provision for neutralizing the acidic conditions provided by the cleaning solution. To solve this problem it has been found that sodium carbonate and tetrasodium pyrophosphate when employed in combination are peculiarly efiective, not only for neutralizing the acidic conditions, but also in securing additional removal of iron rust. Consequently, it is a further aspect of this invention that once cleaning has been conducted employing the combination of oxalic acid and ammonium oxalate, then neutralization and residual cleaning is afiected by employing a combination of sodium carbonate and tetrasodium pyrophosphate.

In addition to the above identified principles, it has furthermore been found that improved radiator cleaning is possible by incorporating a small per cent of a suitable detergent with the cleaning composition comprising the oxalic acid and the ammonium oxalate. The detergent compound is apparently effective in cooperating with the other constituents of the cleaning agent to facilitate the removal of rust from the radiator. It is probable that this action is related to freeing of the iron rust from oil or oil films which may be present in the radiator.

In order to evaluate the cleaning compositions and techniques of this invention a large number of actual tests were conducted employing a variety of cleaning agents and cleaning compositions. In these tests badly corroded automotive radiators were subjected to different cleaning operations. By the nature of this work it was impossible to secure strictly comparable quantitative results. Consequently, in testing any particular cleaning composition, the composition was emploved in many radiators so as to average out diflferences in the condition of these radiators.

Consequently, the observations to be presented hereafter are based on the examination of cleaning results in literally scores of radiator cleaning tests.

The results of these tests were determined in large part by qualitative visual observations. Thus, it is effective in evaluating a cleaning composition, to visually note the quantity and nature of iron rust which is removed when employing a given cleaning composition. At the sam time, the actual amount of iron rust freed from the radiator was weighed so as to provide an actual indication of the amount of rust removed from any particular radiator.

The actual cleaning technique employed was to first flush out the radiator concerned with fresh water. The radiator cleaning composition was then placed in the radiator and the engine was operated for a period of 30 minutes. At the end of this time the cleaning solution was drained from the radiator for determination of the amount of iron rust removed. Thereafter the radiator was flushed with water and the neutralizing solution was then placed in the radiator.

Again the car engine was operated for at least 30 minutes while the neutralizing solution was contained in the radiator. Finally the radiator was drained of the neutralizing solution and was once more flushed with water.

In conducting these tests, one pound of the particular cleaning solution to be employed was dissolved in sufficient fresh water to fill the-radiator to be cleaned. In general, the radiator capacity is 14 quarts, although in some cases radiators contain as much as 16 quarts of water. After the cleaning operation, in the subsequent flushing operations, the neutralizing agent, was employed by adding two ounces of the particular neutralizer to the radiator when filled with clean water.

In conducting tests of this naturethe following results were secured:

First, with regard to results obtained with different types of cleaning agents, it was found that in general about 0.3% to 1.2% of iron oxide was removed from the radiator, based on the total weight of fluid contained in the radiator. In a first series of tests in which oxalic acid alone was employed as the cleaning agent, it was found that the rust was removed from the radiator in a caky form. In a second series of tests. employing ammonium oxalate as the cleaning agent, it was found that the iron rust was removed from the radiator in the form of a fine powder. In each case the extent of rust removal or radiator cleaning was about the same with either of these agents when employed individually. However, it was apparent from the nature of the rust removed, as indicated, that. the two agents attacked the rust of the radiator in a somewhat different manner. Consequently, a third series of tests were conducted in which approximately equal parts, that is about /2 pound each of oxalic acid and ammonium oxalate were employed. In tests of this nature, applied to more than 60 automobile radiators, it was found that the combination of oxalic acid and ammonium oxalate was effective in removing about 20 to 25% more rust than when the same oua'ntity of either chemical was employed by itself.

Tests of this same general character were then carried out with a variety of possible neutralizing agents. Of particular significance were the tests conducted with sodium carbonate alone and with tetrasodium pyrophosphate in combination with r sodium carbonate. In the case in which sodium carbonate was employed alone as a neutralizer,

it was found that a definite attack was made on copper present in the radiator. When the neutralizing solution was drained from the radiator it was found to contain a substantial quantity of dissolved copper. In addition, it was noted that the neutralizing solution, consisting of sodium carbonate alone, was ineffective in securing any additional removal of rust from the radiator; that is, in addition to'that removed by the prior use of the cleaning solution. However, in tests em loying approximately equal proportions of sodium carbonate and tetrasodium pyrophosph'ate it was found that substantially no copper, or at worst, simply a trace of copper was removed from the radiator by the neutralizing agent. Furthermore, a definite quantity of loosened iron rust was in some manner removed from the radiator byutilization of this specific neutralizing composition.

employed having a weight of about 20 gms. These strips were treated to remove all iron oxide or rust from their surface. Thereafter the strips were maintained in contact with water for a period of 24 hours to permit formation of a rust film. These strips were then placed in contact with a cleaning solution for a period of 24 hours. The solution was then analyzed to determine the amount of iron removed in the form of iron oxide by each of the cleaning solutions tested. It was established that iron oxide, rather than iron, was the material removed by the cleaning solution. In each case the particu-. lar cleaning agent employed was dissolved in water to provide a cleaning solution of 3% concentration.

In a first series of tests ammonium oxalate was employed alone as a cleaning agent for the prepared rusted strips. In a typical test using the ammonium oxalate alone the iron strip prior to treatment weighed 21.7 gms. After 24 hour contact with the cleaning solution the iron strip weighed 21.1 gms. indicating that the ammonium oxalate solution alone was eflective in removing 0.6 gm. of iron oxide.

In a second series of tests a similar solution containing oxalic acid alone was employed. In this case the initial weight of the iron strip was 21.? gms., and the treated weight 21.2 gms., indicating removal of about 0.5 gm. of iron oxide.

Finally, in a third series of tests, sufficient ammonium oxalate and sufiicient oxalic acid was dissolved in water to provide a 1 /2% concentration of each of these constituents. On treating rusted iron strips with this cleaning agent, in

typical tests, it was found that a rusted iron strip having an initial weight of 23.2 gms., was reduced to a weight of 22.1 gms., after treatment, indicating rust removal of about 1.1 gms. of rust. In comparing this example with the two preceding examples, it is apparent that either oxalic acid or ammonium oxalate alone is capable of removing about the same amount of rust. However, whenthe two chemicals are used in combination, substantially twice the amount of rust 7 can be removed when employing the same total weight of cleaning agent.

As described therefore-the cleaning technique of this invention requires a first step cleaning treatment employing a eo m binat i qn of oxalic 931 5 51 emmqniumpxamte api fi 'ir equ'afil proportions. It is particularly contemplated thatabout one pound of this composition should be employed, or in other words, '/2 pound of each of the agents is to be used. It is apparent that the particular proportions of the two agents may be varied or that the total weight of the cleaning compound may be varied. In a second step of the cleaning process, after sturing, a neutralizing agent is employed consisting of about equal proportions of sodium carbonate and tetrasodium pyrophosphate. 'It is particularly contemplated that about one ounce of each of these ingredients be employed to provide a total weight oftwo ounces, although again .the proportions of these agents and the total quantities of the agents may be somewhat varied. As indicated, it is also within the scope of this invention. to include a minor proportion, as for example'about 5%, of a detergent in the cleaning solution, in combination with the oxalic acid and the ammonium oxalate.

What is claimed is:

The process of cleaning the radiator of an automotive type engine comprising the steps of dissolving about one pound of a composition consisting of about equal parts by weight of oxalic acid and ammonium oxalate in water contained in said radiator, operating the engine for a period oi about 30 minutes, draining the said solution of oxalic acid and ammonium oxalate, filling the radiator with an aqueous solution of about two ounces of a composition consisting of about equal weight proportions of sodium carbonate and tetrasodium pyrophosphate, and thereafter draining this solution from the radiator.

HUGH C. DE HOF'F.

6 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Smith Nov. 4, 1924 Peterson et a1 Apr. 10, 1934 Winning et a1 Jan. 23, 1935 Jochum et a1 May 23, 1939 Tremaine Feb. 22, 1949 Eichwald Apr. 11, 1950 OTHER REFERENCES Chemical Formulary, Bennett, vol. 6 (1934), pgs. 454 and 492.