| PLURAL COMPONENT
PROPORTIONING SYSTEM FOR EPOXY PAINTS Revision: 8/96 Process Code: Navy and Marine Corps: ID-05-99; Air Force: PA01; Army: PNT Usage List: Navy: Low; Marine Corps: Low; Army: Medium; Air Force: Medium Substitute For: Manual Paint Mixing of Epoxy Paints Applicable EPCRA Targeted Constituents: Toluene (CAS: 108-88-3), Xylenes (CAS: 1330-20-7), Methyl Ethyl Ketone (CAS: 78-93-3), Acetone (CAS: 67-64-1), n-Butyl Alcohol (CAS: 71-36-3), Lead (CAS: 7439-92-1), Chromium (CAS: 7440-47-3), Zinc Compounds Overview: Plural component proportioning systems are self-contained epoxy paint
proportioning and mixing systems. These systems provide proper mixing and
precise generation of paint required by an application and consequently
generate minimal waste. Epoxy paint mixtures are prepared by premixing a base and a catalyst,
and combining them in appropriate proportions in a separate container.
After mixing and waiting the specified time, application of the paint to
the workpiece may proceed. Epoxy paint ingredients have a limited pot life
once mixed which cannot be exceeded without affecting the characteristics
of the paint. If the pot life is exceeded, the mixture must be disposed,
and the application equipment must be cleaned with a solvent. Under
conventional methods, the mixture is prepared by hand. This frequently
results in the generation of excess paint, which requires solvent cleanup
and disposal of the paint and solvent as a hazardous waste. Plural component proportioning systems are used in conjunction with
application devices. The proportioning and application system layout
typically includes the following components: 1) proportioning pump module,
2) mix manifold, 3) mixer, 4) application device, 5) material supply
module, and 6) purge or flush module. These systems optimize painting
operations by maximizing efficiency and minimizing waste generated. The plural component proportioning system for epoxy paints provides
total control of materials from container(s) to application. They are
accurate and can provide more consistent material quality than hand
mixing. These systems can also keep pace with higher production
requirements. They mix on demand (i.e. as the gun is triggered), which
results in no significant quantities of wasted materials. Material cleanup
requires less labor and maintenance, and generates less waste because the
mixed material can be purged with solvent from the mix manifold, mixer,
hose, and applicator before it cures. The plural component proportioning
system is a closed system and, as a result, there are fewer spills, less
contamination or waste to clean up, and less contact between personnel and
potentially hazardous materials. In addition, the proportioning system
makes bulk purchase of material practical. If an epoxy paint requires a significant induction time (15 minutes or
longer) the plural component proportioning system can still be used,
provided that the mixed paint is allowed to stand in a separate container
prior to application. No new wastestreams are generated using Plural Component Proportioning
Systems as compared to conventional methods. Materials Compatibility: Material specification data for the epoxy paint materials needs to be
evaluated with respect to the proportioning and application system
components prior to specification of the actual system to ensure material
compatibility. The materials used for the pumps and packings need to be
evaluated on a case-by-case basis. Stainless steel and TeflonŽ components
do not pose compatibility problems with most materials used in epoxy paint
operations. Safety and Health: Health concerns are dependent on the variety of paint that is used.
Inhalation of lead- and zinc chromate-based paints can lead to irritation
of the respiratory system. Some lead compounds are carcinogenic.
Solvent-based paints can irritate the lungs and mucous membranes.
Prolonged exposure can affect respiration and the central nervous system.
Proper personal protection (PPE) equipment should be used. These safety
and health issues are also applicable when using conventional methods. Consult your local industrial health specialist, your local health and
safety personnel, and the appropriate MSDS prior to implementing this
technology. Benefits:
Disadvantage:
Economic Analysis: Capital costs for plural component proportioning systems can range from
$50,000 to $70,000 for systems that mix multiple materials or $6,000 to
$7,000 for basic units that mix two materials. Application systems are
additional and their capital costs can range from $500 to $5,000. Each
application needs to be evaluated on a case-by-case basis with respect to
material and labor costs and savings. The following is an example of the replacement of a hand-mixing paint
operation with a relatively simple Plural Component Proportioning
System. Assumptions:
Plural Component Proportioning System and Hand Mixing System
Economic Analysis Summary
Approving Authority: Navy: Approval is controlled locally and should be implemented only
after engineering approval has been granted. Major claimant approval is
not required. Point of Contact: Scott Mauro Vendors: The following is a list of plural component proportioning system
manufacturers. This is not meant to be a complete list, as there may be
other manufacturers of this type of equipment. DeVilbiss Ransburg Industrial Liquid Systems Graco Inc. Binks Manufacturing Company Source: Mr. Jeff Smith, DeVilbiss Ransburg Industrial
Liquid Systems, Toledo, OH |