The
Occupational Safety and Health Administration (OSHA) requires that all
open tanks that are heated, or that contain acids, must be ventilated.
In addition, most states now have laws requiring that manufacturing plants
inform workers of potential hazards associated with chemicals used in
the workplace. These facts, coupled with a desire on the part of industry
to create a safe work environment, generally lead to installation of some
type of ventilating system for the electropolishing shop.
Ventilation equipment furnished by MCP for electropolishing lines is constructed
from rigid PVC sheet and extruded shapes. Joints are welded to eliminate
leaks and to provide rigidity. All fittings and ductwork are designed
to ensure smooth flow of air at constant velocity. Hoods are fitted with
quadrant-type dampers to permit balancing of the system under various
operating conditions.
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This line includes an 8,000 cfm push-pull ventilation system to
control air quality to current OSHA standards. The vertically mounted
hoods are connected by PVC duct to the pull fan mounted outside
the building. The push air ductwork is mounted on the front rim
of the tanks. |
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| System
designs vary with the layout of the electropolishing line. The most
common systems utilize upright, slotted hoods at the rear of the
tank, allowing sufficient clearance for passage of the materials
handling hoist. Hoods are connected by appropriate PVC ductwork
to the main fan mounted on the roof or on a stand outside the building.
Fans are sized for the total air flow requirement and are constructed
entirely of PVC. |
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The pull fan for the ventilation system is located on a steel platform
stand as shown in the image above. All components of the ventilation
system are constructed from corrosion resistant PVC and are welded
to eliminate the possibility of leakage. |
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| Some
tank configurations require "push-pull" ventilation for maximum
efficiency. In such cases, the draft created by the main fan is
augmented by a blower designed to force air through a distribution
system and to sweep the fumes from the front of the tank toward
the vertically mounted hood. In special cases, lateral or down-draft
hoods may be required. |
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The centrifugal blower shown above furnishes the push-air for the
ventilation system. The push-air aids in reducing the total air
volume needed for proper control of the chemical vapors and moisture. |
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The
line includes an 8,000 cfm push-pull ventilation system to control
air quality to current OSHA standards. Shown above is the push air
blower, located on a concrete pad outside the building. Push air
ductwork can be seen in the photo above this one, mounted on the
front rim of the tanks.
MCP ventilation systems are professionally designed for electropolishing
lines. Guidelines used are those of the American Conference of Governmental
Industrial Hygienists. OSHA standards, as published by the Federal
Register, CF29CFR1910, are followed. Each ventilation system is
specifically designed to fit the space available in the electropolishing
shop. The customer must furnish certain details such as the roof
height and type, the electrical power requirements, and other details
which may affect air flow. Plan and elevation drawings are routinely
submitted for customer approval prior to the start of construction
of the ventilating system.
Specific quotations must be developed for most lines. MCP will include an estimate of the ventilation cost with all requests for quotation. Please fill out and email to MCP the form entitled "Quotation Request" found on this web site.
Approximate Cost of Adding a Complete Ventilation System to the
MCP "Standard"
Series of Equipment: |
| Discharge
of waste water from electropolishing lines is governed by the Environmental
Protection Agency (EPA) and related state and local authorities.
Electropolishing shops must be in compliance with all Federal, State,
and Local requirements for waste water discharged to ground water
or to a Public-Owned Treatment Works (POTW). In general, MCP recommends
that electropolishing lines be located on a sewer line discharging
to a POTW. |
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Above a semi-automated batch waste treatment unit neutralizes up
to 2000 gallons of rinse water per shift. The system can be upgraded
for automatic operation by modification of the computer control. An optional filter press can be added to minimize operator supervision
and to maximize throughput of waste water. |
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The
MCP system for handling waste treatment divides the total effluent from
the
line into two parts:
1. The
"drag-out" from the electropolishing tank and its rinse(s), and,
2. The
"acid/alkali" waste water from the cleaner, the acid descale, and the
post-treatment nitric acid.
Waste
water from the "acid/alkali" tanks and their rinses is collected
into a common sump, from which the combined waste water is pumped
to a storage tank of suitable capacity. The combined effluent is
tested for pH and other chemical and physical parameters specified
by the waste water authorities. If no further treatment is needed,
the combined effluent is discharged to the POTW. If the combined
effluent does not meet the parameters specified by the POTW, pretreatment
is indicated. Installation of a pretreatment system may require
a special license, and the customer should be diligent in determining
what permits must be obtained.
MCP furnishes skid-mounted batch waste treatment modules specially
designed to handle wastes from electropolishing lines. These modules
usually handle 50 gallons to 5,000 gallons of effluent per day,
and may be either manual or semiautomatic. The standard models utilize
a bag filtration system which produces a pourable solid sludge of
about 15% solids. Options include the addition of a filter press
which further reduces the water content of the sludge to form a
non-fluid cake of about 30-40% solids. Sludge drying equipment is
also available for reduction of the weight and volume of the filter
cake. Continuous flow systems can be offered for systems requiring
large water volumes. |
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Shown here is a manually operated batch waste water treatment unit
that handles up to 2600 gallons of rinse water per shift. The waste
water produced by the system is minimized through the use of a thin-film,
atmospheric evaporator designed to concentrate the electrolyte recovered
from the rinse water. |
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| Properly
operated, the skid-mounted batch waste treatment system produces
a clear liquid suitable for discharge to the POTW and a solid, metal
hydroxide sludge which must be shipped to an approved hazardous
waste landfill. The customer is furnished with a conditional warranty,
guaranteeing that the system will meet the EPA and/or local requirements.
Costs for the skid-mounted systems range from $22,700 for the manually
operated model with bag filter system to $65,500 for the semiautomatic
model with sludge settling device and filter press. |
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