p 4 - Y Abar Ipsen Industries

Vacuum Degreasing Systems '*

Cleming up the environmental dangers of parts degreasing

Parts degreasing, a process that on the surface would appear

to be fairly straight-forward, is becoming somewhat problematical for a

host of basic and high technology industries. Metal stamping

manufacturers in the automotive and other industries, machinery

manufacturers, aerospace and transportation industries, surgical and

medical instrument makers, job shop platers and refinishers and others are

seeing operating costs associated with parts degreasing rise dramatically

due to new EPA requirements, so-called consumption taxes, oil recovery

efforts and labor and overhead expenses.

The two most prevalent part cleaning processes in use today by

these industries are vapor degreasing and detergent cleaning. A third

process -- vacuum degreasing -- offers the promise of avoiding the

problems associated with the commonly used cleaning methods and

providing a cleaner, more efficient degreasing option that includes oil

recycling opportunities.

The Solvent Problem

Solvent use is widespread in industry and its dangers are a concem

of the EPA and users alike. Plus, the costs associated with the use of

solvents in processes such as vapor degreasing -largely because of EPA

requirements and consumption taxes - are becoming prohibitive. The

accountability requirements alone - in terms of the paperwork needed to

stay within the law - are daunting for large and small companies alike.

Vapor Degreasing Limitations

Vapor degreasing systems use chlorofluorocarbon-based solvents to

clean metal and some non-metal parts by vapor condensation on cool parts.

Fluids used include methylene chloride, percholorethylene, 1,1,1-

trichloroethane, trichloroethylene, trichloro-trifluoro-ethane and other

constant boil& fluids.

With vapor degreasing, heated vapors which are heavier than air

tend to stay contained within the treatment tank Some tanks are equipped

with distillation equipment which permits reuse of the working fluid and

concentration of the waste. In the process, the parts must be heavy enough

so that vapors wash away and dissolve the oils before the parts are heated

to the same temperature as the vapor. Some time is required to achieve

part heating and draining. Of course, there are many options available to i

enhance the cleaning performance of this equipment.

The Alternative in Principle

Vacuum degreasing of metal parts is already used by many

companies. The principle of vacuum boil-off of oils has been demonstrated

for many years in distillation towers. The principle is sound; however,

current techniques do not take full advantage of all the benefits inherent in

this process.

Vacuum furnaces have been used to effect the boil-off of oils for

many years. Here is the problem with forcing vacuum furnaces to do

double-duty as degreasing systems: the oil that has condensed on the water-

cooled vessel waUs can re-vaporize at high vacuum conditions. Drawn

through the furnace diEusion pumps, this oil can degrade pump

performance. To maintain the integrity of the equipment, frequent

cleaning of the hot zone, tank walls and pump components must be

performed.

A further drawback of this technique is that it does not include any

oil recycling capabilities.

Adapting Existing TechnoIogy

Recent efforts by the Abar Ipsen Industries Special Products Group to

- specially adapt existing furdace technology -- the company's area of

expertise - to help solve the problems associated with parts degreasing

have produced a new entry in the field.

The process is effective; but users are now finding that the expenses

incurred to properly dispose of oils containing chlorofluorocarbons 0- toxic

waste, really -- are eroding profits. Also, recycling oiIs with EPA-controlled

chlorofluorocarbon contaminants is expensive.

Ultrasonic Vapor Cleaning

Ultrasonic vapor degreasing is essentially the same ‘as vapor

degreasing except parts are subjected to an additional ultrasonic process to

enhance cleaning. Toxic waste disposal and all of the other problems

common to solvent usage are still concerns here.

Washer Saponification Limitations

Washer cleaning eliminates the use of chlorofluorocarbons at the

expense of speed and efficiency. The process is labor intensive and

involves extensive equipment downtime to faditate cleaning and other

maintenance requirements. Several tanks are required; the water must be

co&tantly changed; and the tanks must be cleaned repeatedly. Also,

dangerous acids and caustics must be used to emuhi.@ the oils.

Reclamation of oils in this process requires extensive and expensive

waste-water treatment to separate the oil and water. 5

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Abar Ipsen's vacuum degreasing system design physically separates

oils from metal parts; collects oils for recycling; and eliminates the furnace

wall oil deposit problem through the use of a unique hot-wall degreasing

method. The secret to the design is the control it provides over where the

# vacuum vapors condense; this, in turn, reduces pollution emissions to

allowable levels.

The benefits of this system over the existing processes include the

elimination of solvent handling, treatment, storage and disposal costs found

with vapor degreasing; and the elimination of caustic chemical usage, high

maintenance requirements and large floor space required of chemical

cleaning. Plus, parts requiring other types of heat treatment under vacuum

do not become water soaked with this degreasing method. Finally, oil

recycling, in most cases, is a simple process with this system.

Design Advantages vs. Existing Systems

The advantages of hot-wall degreasing over the vacuum furnace

technique lie in the reduction of the maintenance costs and the recycling

benefit.

With this equipment, oils will not condense on the vessel walls

-because the walls are hotter than the vapor. Vapors are pumped to a cold

condenser which acts like a cold-trap. A mechanical vacuum blower and

forepump continue pumping non-condensable gases.

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Oil condenses on a series of tubes and fins in a refrigerated heat

exchanger in the system. Later in the process cycle, the condenser is

isolated from the vacuum and warmed, causing the oil to drain to a sump

for recycling or disposal. This feature eliminates the frequent cleaning and

maintenance required in systems without hot-wall shells. Also, separating

the oil before the cross-over to high vacuum prevents diffusion pump oils

from becoming prematurely degraded.

New Component Designs Required.

A new type of vessel design was required for the development of

hot-wall degreasing. The vessel wall operating temperature is 500°F; while

insulation maintains sheathing temperatures under 100°F (ambient 80°F).

A double wall design provides a vacuum interface between the inner and

outer walls of the furnace chamber, allowing the inner wall to maintain

temperatures above the condensing temperature of the oil to be removed.

This assures nearly all of the oil or grease is pumped to the refrigerated

condensing trap.

The vessel is supported and anchored to eliminate stresses and local

bending from thermal expansion and contraction. Penetrations permitting

thermocouple use are located near the door flange to reduce thermal

!

i stresses, as well.

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The second hurdle in arriving at a fully realized system involved the

design of the refrigerated condenser. The design had to allow the

condensation of oil vapors outside of the hot-wall vessel and upstream of

the vacuum pumps. This configuration prevents oil from the degreasing

process from degrading the vacuum pump oils. The refrigerated condenser

also acts like a eryopump - increasing the effective pumping speed.

Pumpdown time is dependent on the mass of the load being heated

and the vapor pressure of the oil being removed. When equilibrium is

reached, the oil vaporizes from the work and condenses on the condenser

plates.

A typical pumping schematic is shown here. The arrangement

allows rapid pumping that bypasses the condenser at vacuum pressures

over 25 Torr. Oil vaporization does not start until pressures are below

1000 uHg. Semi-continuous processing can, according to Abar Ipsen, be

accommodated by using dual condensers.

The coils in the condensers are cooled by refrigerant. Earlier

'designs used chilled water. This, however, required a refrigerant cooling

system receiving 50°F to 60°F water. (Furnace and diffusion p&p water

seldom runs below 9OOF.) The direct refrigerant cooling system eliminates

the need for water circulators and conditioners. Also, lower temperatures 5 . could be achieved in the vacuum-system, allowing, in turn, higher capture

coefficients for the condensables,

The refrigeration system also includes a hot gas defrost loop that

allows the coils to be heated to reliquify oils and drain them from the

condenser. The condenser is isolated from the vacuum pump and vessel

during defrosting. Gas flows down across the heat exchanger fins and

encourages the flow of oil

into the sump. The mist laden gas stream then passes through a demister

to reduce combustibles content and is subsequently vented. A flare vent

stack may be required to reduce the emission of remaining combustibles to

acceptable EPA limits.

Basic Configurations

The system's vessel is designed so that it can be configured for

either horizontal or vertical operation. Vertical units can be top or bottom

loaded. A variety of sizes are available to meet various batch applications.

According to the manufacturer, the degreasing system can be used

in clean room applications by adding a vacuum jacket to the vessel. Also,

ports can be added to the vacuum chamber for RGA, optical pyrometer or

spectroscopy analysis and cleanliness verification.

To assure the safety of the operators, the system is designed to

backfill with nitrogen and/or air prior to the removal of parts. Inert gas

cooling is also available.

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Environmental Concerns

An array of technology -- some of which can be bundled with the

Abar Ipsen equipment -- is available to eliminate the relatively minor

environmental hazards associated with vacuum degreasing. Vented gas

and air streams, vacuum pump exhaust and machine fumes can be treated

using filters, electrostatic precipitators, demisters and other types of

equipment to stop unsafe emissions into the plant air and outside

atmosphere. Also, cooling water and other liquids should be treated to

meet clean water standards. Solids remaining in the chamber can be

concentrated by chemical or thermal processing and disposed of safely.

Low boiling point oil components which evaporate off but are not

collected on the condenser because of high vapor pressure can be

incinerated in flare vent stacks. This converts most of the mass to carbon

dioxide and water. The remaining waste ash must be tested and disposed

of in a land €ill or by other appropriate solid containment methods.

Recycling Oils

Recycling many of oils collected during the vacuum degreasing

process requires only ultra-fine filtering. Some oils, however, may be

degraded in the process. These products may require additives or re-

blending to recapture original specifications. 5

According to Abar Ipsen, the company will test small work samples

from prospective purchasers to determine recycling potential and the

overall viability of the vacuum degreasing process for specific applications.

Of course, if the oils originally contained no hazardous constituents,

they could be burned as waste oil. Contaminated oils could not be

recycIed and might require more extensive treatment prior to disposal.

Market Potential _.

Abar Ipsen sees initial appeal for its system among current vapor

degreaser users who use large quantities of solvents. According to the

firm, the market should expand quickly as the viability of the equipment is

further demonstrated.

Oil & Parts Testing Procedures

Potential users of Abar Ipsen's vacuum degreasing system may submit

sample oil and small parts to evaluate results for their specific applications.

Full test request instructions and pricing information can be obtained by

writing Abar Ipsen

-Blvd., Feasterville,

Industries, Special Products Group, 905 Pennsylvania

Pa 19047.

1. Sample Submission

* Submission of Material Safety Data Sheets prior to

acceptance of samples for testing.

* Prepare and ship one quart or liter of sample of oil in a DOT

approved container for Hazardous Materials properly

labeled.

2. Sample Testing

* VerScation/Classication

Density Check

Viscosity Measurement

* Vapor Pressure vs. Temperature

Determine boiling point range at atmospheric pressures

per ASTM D86

Bell jar testing to determine boiling temperature at reduced

pressures

* Product Configuration Testing

Parts tested in hot-wall furnace with oil condensate chamber

to determine actual oil removal and collection rates.

* Cleanliness

Cleaning effectiveness determined using U V light reflectance

and particle size checks. i

3. Test Report

* A computer generated report will be supplied for the testing

performed.

Computer simulation calculations will show temperature and

vacuum vs. time for conditions analyzed.

* Recommended cycles will be listed for the product, furnace

and oil combination evaluated.

Parts DegreasindCleaning Study: A Summary of the Findings

Research reveh industry seeks alternative forparts degrem'ng

A recent research study commissioned by Abar Ipsen Industries,

Feasterville, Pennsylvania indicates that many people involved in industries

where parts degreasing processes are used are seeking alternatives to the

traditional cleaning methods. The conclusion of the survey is that an

environmentally safe cleaning process, such as the Abar Ipsen vacuum

degreasing system, would fulfill a perceived need in these industries and

could help solve a host of economic problems presently confronting users

of vapor degreasing and aqueous/detergent cleaning systems.

AN OVERVIEW

The research study -- in the form of a direct mail survey of a cross-section

of industries where parts degreasing is prevalent -- was conducted in April,

1990. A long and fairly complex survey questionnaire was mailed once to

sample groups in the target industries. The survey audience was not pre-

alerted, nor were there follow-ups to the responses. The response rate .-

achieved --qualified as "good" from a market research standpoint -- indicates that interest in a solution to current degreasing problem is high.

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The survey field consisted of two main groups: jobshop electroplaterslcoaters and

manufacturing engineers in selected industries. These industries consisted of:

* Automotive Stampings (SIC 3465)

* Metal Stampings (SIC 3469)

* Industrial & Commercial Machinery & Computer Equipment Makers (SIC 35)

* Transportation Equipment Manufacturers (SIC 37)

* Surgical, Medical & Dental Instrument Makers (SIC 3841)

* Orthopedic, Prosthetic & Surgical Appliance Manufacturers (SIC 3842)

STUDY RESULTS

Findings based on the responses to the survey included the following (totals in some

response categories exceed 100% because of multiple responses):

Finding 1

Solvent/vapor degreasing systems are st i l l the most widely used cleaning method.

Rankir;gs for the top cleaning methods were:

1. 84.8% - vapor degreasing

2. 26.5 - aqueous detergent

3. 15.9 - ultrasonic vapor

4. 14.4 - biodegradable

5. 12.9 - ultrasonic aqueous

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Finding 2

The major operating cost concerns among the total survey group were labor,

soIvent/detergent use and oil recovery.

Fhding 3

Average number of systems used on-site was 3-4. The number of systems seemed to be

related to the number of times the part was cleaned. Most respondents (48.6%) clean

the part once, 25% clean the part twice and 11.4% three times.

Finding 4

Most respondents (45.4%) used the cleaning stage prior to machining. Plating and

stamping were tied for second (23.5%).

Finding 5

The most commonly removed materials are: oil (unspecified) (37.9%), grease (16.7%),

cutting oils (11.4%) and dirt (10.6%).

Small (72%) and medium size (44%) parts axe the most frequently processed. Steel

(30.3%), a l u m i " (27.3%), stainless steel (17.4%) and brass (10.6%) are the most

commonly cleaned materials.

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Summary

These findings suggest the Abar Ipsen vacuum degreasing system -a self-contained,

ecologically safe parts cleaning method that provides an efficient oil/grease reclamation

capability - would fulfill the process needs of users and at the same time resolve

operating cost problems that are associated with current cleaning systems.

More information on the Abar Ipsen vacuum degreasing system can be obtained by

contacting Abar Ipsen Industries, 905 Pennsylvania Blvd., Feasterville, PA 19053.

Telephone (215) 355-4900.

The Abar Ipsen Group 905 Pennsylvania Blvd. Feastemille, PA 19053

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ABCOR" Ultrafiltration Systems

TREATING FLEXOGRAPHIC INKS AND STARCH WASH WATER BY ULTRAFILTRATION

Cleaning flexographic presses pro- duces a large volume of wash water containing a small percentage of print- ing ink and starch adhesive. In the past, this wash water was discharged directly to sewers. However, current federal effluent guidelines prohibit this practice because of the high color, BOD, and COD content of the wash water.

Unlike chemical treatment and evaporation, ultrafiltration can re- cover and concentrate these diluted inks for reuse. Moreover, the remain- ing water can also be reused.

ULTRAFILTRATION Ultrafiltration is a low pressure-

driven mechanical process for separ- ating and concentrating suspended solids, colloids, and high-molecular- weight materials in solution. A selec- tive, semipermeable membrane retains high-molecular-weight mate- rials (above 5,000), while allowing water and low-molecular-weight sol- utes to pass through. The retained material is called concentrate; the material passing through the mem- brane, permeate.

Unlike ordinary filtration, the waste stream flows parallel to the membrane surface, not perpendic- ular. As a result, no filter cake builds up on the membrane. Moreover, the structure of the membrane itself will not become plugged because the re- tained materials cannot penetrate the membrane. Turbulence at the mem-

Fiberglass-reinforced

0 :.?;. Concentrate <. ~

Wash Water,

' 0 , .;;, ,

. . . . . . . . . . . . . . . . . . . . , . . . . . . . , . , .

" . . ' ( " : p e & e a t e e , .:..;.;,;: . . ; , . _ ' . .(. , ., ..;; ; , . ' . . ' . ' . . . . , , , , ; , , . '. (' ', '; '. ', . , ' . . . . . . . . .:; .. . . .

I Tubular Ultrafiltration Membrane Figure One

CONCENTRATE 40 GPD 25% Ink

ULTRAFILTRATION SYSTEM -

Wash water loo0 GPD 1% Ink I

PERMEATE 960 GPD Figure Two

brane surface caused by the circulat- ing waste stream carries retained materials from the membrane.

~

INK RECOVERY The wash water from cleaning a flex- ographic press may contain 1% to 2% printing ink. With ultrafiltration, a small, concentrated volume of ink is produced for reuse or disposal (if starch is present). The clear water permeate that is also produced can be reused as rinse water, starch adhesive makeup, or used to dilute ink formu- lations. A typical material balance for ultrafiltering flexographic press wash water containing 1% printing ink is shown in Figure Two.

Abcor"

ADVANTAGES Simple. One Step. Reduces pollutant

discharge. Recovers ink and water with no phase change or added chemicals.

Minimal energy requirements. Requires only a recirculation pump.

Minima! operator attention. System operation, including cleaning, can be fully automated.

Reliable. Tubular configuration allows for trouble-free operation with membrane lifetime over 2 years.

Skid-mounted. Complete system- membrane modules, pumps, piping, and instrumentation.

THE MEMBRANE MAKER'" 850 Main Street, Wilmington, MA 01887 U.S.A., Tel. (617) 657-4250 TWX 710 347 6537

@Copyright 1984, Abcor, Inc.