Do not use emery cloth to clean a copper joint. Emery cloth contains oil.
This may hinder the making of a good soldering joint.
Emery cloth is made of silicon carbide, which is a very hard substance.
Any grains of this abrasive in the refrigeration mechanism or lines can damage a compressor. Use a brush to help clean the area after sanding.
CLEANING AND DEGREASING SOLVENTS
Solvents, including carbon tetrachloride (CCl4), are frequently used in the refrigeration industry for cleaning and degreasing equipment. No solvent is absolutely safe.
There are several which may be used with relative safety. Carbon tetrachloride is not one of them.
Use of one of the safer solvents will reduce the likelihood of serious illness developing in the course of daily use.
Some of these solvents are stabilized methyl chloroform, methylene chloride, trichlorethylene, and perchloroethylene. Some petroleum solvents are available.
These are flammable in varying degrees.
Most solvents may be used safely if certain rules are followed.
• Use no more solvent than the job requires. This helps keep solvent vapor concentrations low in the work area.
• Use the solvent in a well-ventilated area and avoid breathing the vapors as much as possible.
If the solvents are used in shop degreasing, it is wise to have a ventilated degreasing unit to keep the level of solvent vapors as low as possible.
• Keep the solvents off the skin as much as possible.
All solvents are capable of removing the oils and waxes that keep the skin soft and moist.
When these oils and waxes are removed, the skin becomes irritated, dry, and cracked. A skin rash may develop more easily.
CAUTION: While commonly used solvent, carbon tetrachloride has many virtues as a solvent, it has caused much illness among those who use it.
Each year several deaths result from its use. Usually, these occur in the small
shop or the home.
Most large industrieshave discontinued its use. It is used only with extreme caution.
A measureof its harmful nature is indicated by the fact that it bears a poison label.
It should never be placed in a container that is not labeled “poison.” It is for industrial use only.
While occasional deaths result from swallowing carbon tetrachloride, the vast majority of deaths are caused by breathing its vapors.
When exposure is very great, the symptoms will be headache, dizziness, nausea,
vomiting, and abdominal cramping.
The person may lose consciousness. While the person seems to recover from breathing too much of the vapor, a day or two later he or she again becomes ill.
Now there is evidence of severe injury to the liver and kidneys. In many cases,
this delayed injury may develop after repeated small exposures or after a single exposure not sufficient to cause illness at the time of exposure.
The delayed illness is much more common and more severe among those who drink alcoholic beverages.
In some episodes where several persons were equally exposed to carbon tetrachloride, the only one who became ill or the one who became most seriously ill was the person who stopped for a drink or two on the way home.
When overexposure to carbon tetrachloride results in liver and kidney damage, the patient begins a fight for life without the benefit of an antidote.
The only sure protection against such serious illness is not to breathe the
vapors or allow contact with the skin.
Human response to carbon tetrachloride is not predictable. A person may occasionally use carbon tetrachloridein the same job in the same way without apparent harm. Then, one day severe illness may result.
This unpredictability of response is one factor that makes the use of “carbon tet” so dangerous.
Other solvents will do a good job of cleaning and degreasing. It is much safer to select one of those solvents for regular use rather than to expose yourself to the potential dangers of carbon tetrachloride.
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