form a cylindrical pressboard (or phenolic plastics). The windings are separated with
series of paper or materials of similar properties, and at the end of the winding
process, the windings are axially compressed to required size, heated, and vacuum
dried to remove residual moisture. Finally, the impregnated oil in the coil is
compressed out. The transformer core is made by stacking strips of steel together
to form the core which is then placed over legs of the core. The assembly, well
insulated with Kraft paper and/or phenolic spacers, has its top yoke dried in a
chamber and later saturated manually with transformer oil. Other processes to
improve the qualities of the transformer are done in different industries.
Large oil-filled capacitor containers are produced manually from steel or aluminum. Since they are used in environments susceptible to corrosion, the surfaces of
these containers are treated with phosphate or chromate before being painted.
Special ceramic insulators are often used to separate the cover from the terminals
in order to avoid discharging. Small oil-filled capacitor containers are made of same
materials as large oil-filled capacitor containers but are fabricated on a dry automatic
impact extruder. The manufacturing processes further involve connection of insulated materials to the interior wiring, soldering of the electrical leads to the terminal
connection on the cover, welding of the cover to the body to form a sealed capacitor,
and oil-filling operations.
Mica paper is produced from mica slurry which is first heated in a kiln before
grinding and re-slurried with water. This is further screened with double serene
separator to separate the undersized and oversized particles. The fine screen slurry is
thoroughly mixed in a mixing pit before being sent to a vortex and then papermaking
machine where remaining moisture content is evaporated. The machine turns out the
mica matrix in a sheet form and this is further cured in an oven before being wound
on rollers having met standard specifications.
2.2.2 Description of Industrial Plant
Different plants producing some of the components under this subcategory are found
in the USA. Plant 30082 is one of the largest oil-filled capacitor plants in the USA.
Plant 43055 is another plant with a large mica paper dielectric manufacturing facility
using 3,300,000 L of water per day.
2.2.3 Water Uses
Less than 5% of the approximated 199 million L/day of gross water used in the
manufacture of wet and dry transformers is processed water employed for
non-contact cooling. In a typical manufacturing plant, for oil-filled capacitor,
water use is mainly for detergent wash process and phosphatizing while solvent is
used in many other processes, thus reducing the volume of water use. However,
paper mica production has the largest water use in this subcategory; its production
process is water dependent, particularly to saturate, separate, flake, and convey the
4 Electrical and Electronic Wastes Treatment
133
series of paper or materials of similar properties, and at the end of the winding
process, the windings are axially compressed to required size, heated, and vacuum
dried to remove residual moisture. Finally, the impregnated oil in the coil is
compressed out. The transformer core is made by stacking strips of steel together
to form the core which is then placed over legs of the core. The assembly, well
insulated with Kraft paper and/or phenolic spacers, has its top yoke dried in a
chamber and later saturated manually with transformer oil. Other processes to
improve the qualities of the transformer are done in different industries.
Large oil-filled capacitor containers are produced manually from steel or aluminum. Since they are used in environments susceptible to corrosion, the surfaces of
these containers are treated with phosphate or chromate before being painted.
Special ceramic insulators are often used to separate the cover from the terminals
in order to avoid discharging. Small oil-filled capacitor containers are made of same
materials as large oil-filled capacitor containers but are fabricated on a dry automatic
impact extruder. The manufacturing processes further involve connection of insulated materials to the interior wiring, soldering of the electrical leads to the terminal
connection on the cover, welding of the cover to the body to form a sealed capacitor,
and oil-filling operations.
Mica paper is produced from mica slurry which is first heated in a kiln before
grinding and re-slurried with water. This is further screened with double serene
separator to separate the undersized and oversized particles. The fine screen slurry is
thoroughly mixed in a mixing pit before being sent to a vortex and then papermaking
machine where remaining moisture content is evaporated. The machine turns out the
mica matrix in a sheet form and this is further cured in an oven before being wound
on rollers having met standard specifications.
2.2.2 Description of Industrial Plant
Different plants producing some of the components under this subcategory are found
in the USA. Plant 30082 is one of the largest oil-filled capacitor plants in the USA.
Plant 43055 is another plant with a large mica paper dielectric manufacturing facility
using 3,300,000 L of water per day.
2.2.3 Water Uses
Less than 5% of the approximated 199 million L/day of gross water used in the
manufacture of wet and dry transformers is processed water employed for
non-contact cooling. In a typical manufacturing plant, for oil-filled capacitor,
water use is mainly for detergent wash process and phosphatizing while solvent is
used in many other processes, thus reducing the volume of water use. However,
paper mica production has the largest water use in this subcategory; its production
process is water dependent, particularly to saturate, separate, flake, and convey the
4 Electrical and Electronic Wastes Treatment
133