|
Equipment |
How equipment is used |
Advantages |
Disadvantages |
| Transfer Machine |
Materials are cleaned in a
washing unit where they remain while perc is extracted in the spin cycle. Materials are
then manually transferred from the washing unit to a separate drying unit. |
Higher volume of materials can be
cleaned over time, because washer and dryer may be operated at the same time. |
Higher level of perc emissions.
One load of materials can contain 2-3 gallons of perc per 100 pounds of material cleaned
after extraction. NOTE:
AQMD Rule 1421 prohibits the installation (as of 12/9/94) or operation (as of 10/1/98) of
transfer machines within AQMD jurisdiction. |
| Dry-to-Dry Machine |
Materials are cleaned and dried
in the same cylinder or drum. |
|
|
| |
Vented
Machines
Solvent-laden air is vented through a carbon adsorber or other
control device before being released to the atmosphere. A fan pulls outside air into the
machine to carry perc vapor to the control device. |
Lower perc emissions than from
transfer machines. |
NOTE: AQMD
Rule 1421 prohibits the operation of any vented machine as of 10/1/98. |
| Closed-Loop Machines
These machines eliminate the aeration step by recirculating perc-laden air
through a control device. |
|
|
| Factory original |
Substantially (about 4 times)
lower perc emissions from well-operated, closed-loop, dry-to-dry machines than from
transfer machines. |
More expensive than converting a
vented machine. |
| Converted (from vented to
closed-loop system) |
Costs less than buying a new
machine. |
Less efficient in removing perc
or cleaning clothes as a factory original closed-loop machine.
NOTE: AQMD Rule 1421 prohibits installation of converted
machines or conversion of vented to closed-loop machines as of 6/9/96. |
