TOYO YOZAI Co., Ltd.

23-14, Minami-cho, Itabashi-ku Tokyo, Japan 173-0027
TEL: +81-3-3974-1731
FAX: +81-3-3974-1777
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TOYO CLEAN COPPER
Q and A TOYO CLEAN COPPER
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Frequently asked Questions
about
TOYO CLEAN COPPER

Comparison with competitors' products

Q: What is different from other products?

The other products containing boric acid which form a glass coating on an inner wall of tubes, lead to troubles by peeling off as time elapses. Products containing alcohol that produce formic acid corrode copper tubes. TOYO CLEAN COPPER differs absolutely from such products in its principle. It generates deoxidizing gas not to leave oxidized scale on brazed parts by means of a catalytic reaction.
No glass is produced. No glass compound from inside of tubes comes off, thus keeping a refrigeration cycle clean.
By the unique protection principle, our catalytic gas method has no side effect while the others' solid material coating methods lead to inherent troubles after brazing. TOYO CLEAN COPPER containing no alcohol causes no corrosion.

Q: What is deoxidizing gas?

The deoxidization is a reverse phenomenon to the oxidation which makes a surface of copper black.
The oxidized scale is made inside copper tubes by a chemical bond between copper and oxygen in the air, which is caused by heat of brazing. It is well known the copper (to be precise, copper oxide) acts as a catalyst which hand over oxygen and absorb the deoxidized gas on its surface.
The deoxidization gas from TOYO CLEAN COPPER takes off oxygen bonded to copper, and slso absorbs oxygen in the air inside the copper tube. Then, the deoxidization gas itself changes into carbon dioxide and water. For this reason, the copper inside tubes is not oxidized and kept clean.
It is reported by experiments that the copper oxide inside the tubes is about 1/30 of traditional nitrogen seal method because of the forcible deoxidization with the copper oxide.

How to use TOYO CLEAN COPPER

Q: How many times to spray from can for each size of tube?

1/4 to 3/8 inches 2 times
1/2 to 3/4 inches 3 times
7/8 to 1 inches 4 times
1-1/8 to 1-1/2 inches 9 times
2 inches and over 20 times

Above is only a rule of thumb. Over dosing(shots) has no additional effects.

Q: Are copper caps on both ends necessary? Caps other than copper are acceptable?

Please put caps on both ends to make the effect secure. They are not necessarily copper made. However, to keep the tube inside clean, use squeezed damped cloth, for example, to avoid dust. Remove the caps and other stuffing after slow cooling down as a basic rule of welding.

Q: How to apply TOYO CLEAN COPPER to the tubes and pipes with many brazed spots? And it's effect?

TOYO CLEAN COPPER is intended to be sprayed to small and local brazed spots to protect the area by generating deoxidizing gas. Never fill whole inside of tubes or pipes to avoid explosion. It works well for the tubes and pipes also with many brazed spots by spraying it to each spot.

Q: Why is painting to a ferrule prohibited?

Circular and even spraying in the number of times corresponding to diameter of the tube will cause a sufficient effect.

Q: What is sticky component in compounds and how does it work?

It is a useful component to prevent an oxidized scale inside the pipes.

Q: Does brazed parts sometimes become dark?

Yes, soot is produced when the flaming occurs by the ignition. But soot is a minute and soft particle that does not clog the pipes and does not damage the rotating machines. The same phenomenon would occur in case of the nitrogen seal method.

Q: Can we use TOYO CLEAN COPPER for new refrigerants?

Yes, we can use it. One of the most promising combination of new refrigerant and refrigerator oil for new refrigerant is the combination of R410A and RB68F. It was verified by an experiment that no precipitated solid in above mixture was found in the cycle test of from atmospheric temperature to -30degree C. After 1000 hour test, no corrosion of aluminum, copper and iron was found when these metals were dipped in above mixture, keeping temperature at 160 degree C (the maximum operating temperature of air conditioner is from 120 to 130 degree C). It was also found that the change of hue in liquid phase was within allowable range by above experiment.

Safety

Q: Is there any affect on human body, especially by the burning smell component after heating?

The gas produced by heating and burning consists mainly of carbon dioxide, water and isobutene. The carbon dioxide and water have no smell. The isobutene smells a little to a sharp human sense. Isobutene is the same hydrocarbon as LPG and acetylene used for brazing and quite harmless unless breathing in fully occupied room. Furthermore, the quantity of isobutene produced from normal usage of TOYO CLEAN COPPER is very small. The TOYO CLEAN COPPER is developed into the present recipe placing priority on the human's safety rather than smell. However, as a matter of course, working area should be ventilated.

Q: Is there any possibility of explosion, during continuous brazing?  

A chance of explosion can not be denied in principle. The product employes the method that the contents of the product are burnet slowly for avoiding the explosion. No explosion has been reported including in case of the experiment. There is a possibility of explosion theoretically if deoxidization gas concentration increases inside the pipes. Generally, when a pipe includes many brazed spots, the pipe is large correspondingly to the number of the brazed spots. Thus, the explosion does not occur as long as the number of times of spraying is proper. As the safest policy, it is recommended no person stands at the area where melted wax can be splashed.

Q: Possibility of inflaming during brazing   

A brazing burner outside the pipes may cause flame. The heat generated from gas sprayed of normal number of times is rather negligibly small compared to the one generated from the brazing burner.

Q: Is there any troubles caused by heating after LPG blowing?  

It depends on LPG content inside pipes. Any problem is not reported by experiments.