WATER -BASED IMMER SION PARTS WASHING

BACKGROUNQ

The objective of any industrial parts cleaning system -- equipment, cleaning fluids, and processes -- is to provide quality cleaning results in a cost-effective, safe, efficient

manner.

Water-based immersion parts washing has had some very basic

problems meeting that objective in the past.

new developments have overcome the problems of the past with a

new approach to equipment design and fluid formulation.

approach has been tested and proven in varied industrial

environments with remarkable success.

Now it seems that

This new

The following explains the basic problems, solutions of the past,

and a new type of equipment and fluid system that offers industry

a new choice in water-based immersion parts washing.

While water-based immersion cleaning has been used in the past,

three basic problems always limited its application.

First, as parts were immersed in the water-based cleaning fluid,

surface oil contamination resulted as the lubricants and

contaminants floated to the top of the fluid.

remained submerged, cleaning could occur. However, as the parts

were brought out of the cleaning fluid thyough the surface

contamination, the parts were recontaminated. A solution to the

surface oil contamination problem is a must for a workable

system.

While the parts

Secondly, as parts are cleaned, the chemical action of the

cleaning fluid created the problem of rapid fluid deterioration.

Rapid fluid deterioration occurred as the fluid emulsified the

contaminants.

process, the cleaning fluid itself became increasingly

contaminated. Saturation of the fluid with the contaminant

resulted in the loss of cleaning effectiveness, requiring that

the contaminated fluid be disposed of and replaced with new

fluid. This fluid deterioration and subsequent changing of fluid

requires that cleaning operations cease while the operator drains

the tank, cleans the residue of contaminants from the interior of

the tank, and refills the tank with fresh fluid. This process is -

expensive in lost production time, labor expense, new fluid cost,

and the high cost of properly disposing of the large quantities

of contaminated fluid.that now qualify as hazardous waste

material. The production stoppages and frequent disposal of the

hazardous waste are major drawbacks to the cost-effectiveness of

While the parts were being cleaned by this

immersion parts cleaning which does not solve rapid fluid

deterioration problems.

The third significant problem of immersion washing is the

prolonged cleaning time required when fluids lose cleaning

effectiveness due to contaminant saturation.

first parts washing occurs in the fluid, contaminants become

emulsified in the fluid and cleaning effectiveness begins to

deteriorate.

the fluid deterioration if parts are to reach an acceptable level

of cleanliness. At some point, the time requirement becomes so

great that use of the fluid is no longer acceptable.

corollary to the second problem of rapid fluid deterioration,

user problems result as previously enumerated.

From the moment the

Cleaning times must be extended in proportion to

As a

STANDARD INDUSTRY APPROACHES TO SOLUTIONS

Various solutions to the problems of immersion washing have been

tried.

three problems.

The following examines some possible solutions to the

First, for solving the surface oil contamination problem,

industry's standard approach has been to create an overflow of

surface contaminants into a separate holding tank. The overflow

from the wash tank drains the floating surface contaminants

through a weir arrangement into the second tank where the

contaminants are allowed to accumulate on the surface.

contaminants are then skimmed from the surface and drained into

disposal containers.

continually pumped back into the wash tank for reuse. This

approach does remove surface oil contamination. However, the

additional equipment costs and operating expenses of such a

system are not very cost-effective. Also, floor space for such

an arrangement is expensive and in some cases is simply

impossible due to restricted space availability.

Fluid in the bottom of the settling tank is

The only other approach to surface oil contamination has been to

so fully emulsify the contaminant that no surface contamination

forms at all. This approach simply adds greatly to the problem

of rapid fluid deterioration.

RAPID FLUID DETERIORATION and EXTE NDED CLEANIN G T I m

The problems of rapid fluid deterioration and extended cleaning

times were, in the past, simply accepted as inherent problems in

water-based immersion cleaning. The accepted method of dealing

with the problems was to change the fluid regularly and to

increase cleaning cycle times toward the end of the fluid's

usable life. Drainage of the spent fluid; expensive, frequent

fluid replacement; and the trouble and expense of proper disposal

of the contaminated fluids have, understandably, kept many

industrial facilities from using water-based immersion parts

washing systems.

THE NEW APPROACH TO WATER-BASED IMMERSION CLEANING

Beginning in 1985, a new approach to immersion parts washing

equipment emerged. The result has been a solution to the three

basic problems of immersion parts washing. The problems are

solved in a new type of equipment which is designed for use with

a specially formulated cleaning detergent.

been proven to work in a wide variety of industrial applications

on a variety of parts and contaminants.

industry with a new choice in parts washing which allows the

replacement of many hazardous solvent cleaning systems.

system operates in the following manner.

The new system has

This has provided

The new

To eliminate the problem of surface oil contamination, the system

employs agitation of a specially formulated fluid. As the

special cleaning fluid -- a mild, non-toxic, biodegradable detergent -- is violently agitated, the turbulence allows the fluid to remove contaminants from the parts and hold the

contaminant in suspension.

fluid turbulence prevents any contamination from forming on the

surface of the fluid. This allows the cleaned parts to be

brought through the fluid surface without any recontamination.

The mixing effect of the continual

The uniqueness of this approach is not in the agitation alone.

Previous use of agitation in parts washing was only intended to

clean contaminants from the parts through a scrubbing effect.

Elimination of surface oil contamination has not previously been

a consideration in employing agitation. However, this new

approach combines agitation from a fluid turbocharger with the

effects of an unstable detergent fluid that only mixes with the

contaminant when the fluid is agitated. This solves the problem

of surface oil contamination -- but with far-reaching added effects.

The unstable detergent holds the contaminant in suspension until

the fluid is allowed to enter the oil catcher section of the

turbocharged agitator unit. In the calm oil catcher section, the

fluid allows the contaminant to float to the surface of the

fluid. This separation occurs once the mixture of detergent and

contaminant is no longer subjected to agitation. The separation

occurs continually, allowing the constant recycling of clean

fluid back into the washing area of the tank.

The contaminant is then skimmed from the surface of the oil

catcher section using a polymer or stainless steel skimmer wheel.

Wiper blades clean the contaminant from the wheel, draining it

out the rear of the unit for collection and proper disposal. In

this system, the user only has to deal with quantities of the

original contaminant -- not with a larger quantities of

contaminated cleaning fluid.

The turbocharger unit, including agitator, oil separation area,

and tramp oil skimmer, is an integral part of the equipment and

does not occupy floor space outside the tank. The turbocharger

-- by providing the required agitation in the cleaning area and the calm area for oil separation and skimming -- automatically cleans the cleaning fluid while the cleaning fluid cleans the

parts. Since the fluid is constantly being cleaned, rapid fluid

deterioration is prevented and cleaning times remain consistent.

The system does not, therefore, require frequent fluid dumping

and disposal, preventing expensive production shutdowns and labor

requirements for fluid changes. In addition, the cost of

replacement fluid and contaminated fluid disposal is reduced.

This new approach, combining an agitator, a specially formulated

unstable detergent fluid, a calm oil separation area, and a tramp

oil skimmer provides a complete solution to the three basic

problems of water-based immersion parts washing.

APPLI CATION OF THE NEW A PPROACY

Once the solution to the three problems of water-based immersion

parts cleaning was found, proving the applicability of the system

in actual industry applications followed over a period of months.

Application of the new approach to both small and large-scale

systems was tested in actual industry operations. Results proved

that systems ranging from two (2) gallons to over 5000 gallons in

fluid capacity were equally well-suited to the turbocharged

cleaning approach.

width, and depth. Direction of the turbocharged fluid output

varied as different applications required top and/or bottom

agitation, side agitation, and in long tanks for tube cleaning

applications, agitation directed lengthwise from the end of the

tank. All methods of agitation proved viable.

Tank configurations varied widely in length,

Multistage parts cleaning applications employed the new system

for washing, rinsing, and other treatment processes with

consistent success.

- With the basic three problems of water-based immersion parts

cleaning solved, the principal focus then became the integration

of a variety of parts handling methods to transport parts into

and out of the turbocharged tank. Such methods included hoists

-- manual and programmable, monorails, conveyor belts, and chain conveyors. Cleaning systems using various sizes of beltwashers,

hoists, chain conveyors, and a monorail have all been field

tested and proven with the new system under full production

conditions. In actual installations, both fully automated and

manual systems or combinations of the two have operated

successfully.

The new system has also proven its applicability to both systems

which handle parts individually and in varied containers.

These tested and proven applications in industrial manufacturing

and job shop environments have shown that this new approach to

cleaning has the adaptability, capability, cost-effectiveness,

safety, and cleaning ability to make it a viable option for parts

cleaning in a large number of industrial applications both now

and in the future. It is particularly applicable where hazardous

solvent vapor degreasing systems require replacement due to EPA

and/or OSHA compliance problems or the expense connected with

hazardous solvent usage.

T R I P REPORT

I. PURPOSE

To observe Bowden Indus t r i es aqueous based degreasi ng machines and discuss t h e i r features compared t o ch lo r i na ted so lvent based degreasing machi nes.

I I. PLACE AND DATE

Bowden Indus t r ies , Inc. 1004 Oster Dr ive, N.W. Huntsvi 1 le , Alabama 35816 A p r i l 7, 1988

I I I. ATTENDEES

Donald R. Bowden, President Neal A. Neumann, Pub l ic Relat ions John Murphy, Market ing Davi d Beck, EPA/Emi s s i on Standards D i v i s i on

I V . DISCUSSION

Bowden Indust r i es i s a young company manufacturing degreasi ng systems t h a t employ aqueous based c lean ing f l u i d s . While the concept o f aqueous based c lean ing o f s o i l e d p a r t s i s no t new, Bowden has incorporated several innovat ive features i n t o t h e i r products t h a t se t them apar t from o ther manufacturer 's machines. Bowden's aim has been t o overcome t h e inherent disadvantages o f aqueous cleaners t o p rov ide c leaning systems w i t h wide appl i cabi 1 i ty and d i s t i n c t economic and envi ronmental b e n e f i t s compared t o e x i s t i n g aqueous and so lvent based products.

s e l e c t i o n ideas t o improve c lean ing a b i l i t y , cu t c leaning time, and d r a s t i c a l l y reduce t h e amount o f waste generated by t h e c lean ing process ( t o perhaps 1% o f t y p i c a l aqueous cleaners). pa ten t on a key component o f t h e i r machi nes, t h e "L iqu id Turbo-Charger"."

Rather than at tempt t o discuss t h e techn ica l d e t a i l s o f Bowden's machines, at tached t o t h i s t r i p repo r t i s a discussion, prepared by Bowden, desc r ib ing t h e weaknesses o f c o n v e n t i o v l aqueous based cleaners and t h e steps they have taken t o overcome them,:: Also, at tached are brochures desc r ib ing standard equipment Bowden manufactures and p i c t u r e s o f some equipment Bowden has manufactured.

To accomplish t h i s Bowden has used novel design and detergent

They have obta ined a

.. .

The v i s i t inc luded a t o u r o f Bowden's manufacturing f a c i l i t i e s where I observed demonstration u n i t s i n operat ion, machine assembly, and machi ne check-out p r i o r t o shipping. capaci ty f o r t h e near fu tu re , but because o f very r a p i d growth they a re working on expansion plans. The i r c l i e n t s inc lude several l a rge corpora- t ions .

Bowden has adequate product ion

CONCLUSION

P r i o r t o my v i s i t t o Bowden, i t was my impression t h a t s u b s t i t u t i o n of aweous based c leaning f o r so lvent based degreasing would be l im i ted . Whi 16 e x i s t i n g aqueous systems can be s a t i s f a c t o r y f o r some app l ica t ions , t h i s conclus ion was based on an aqueous c leaner 's genera l l y h igher opera t ing cos ts and i n f e r i o r c leaning c a p a b i l i t i e s compared t o so lvent degreasi ng. aqueous c l eani ng d i sadvantages. Thei r rap i d growth and b lue ch ip corpora- t i o n c l i e n t s a t t e s t t o the v a l i d i t y o f Bowden's c la ims f o r t h e i r products. The i r systems should be app l icab le t o the vast m a j o r i t y o f c lean ing needs now served by t h e ch l o r i nated so l vents. c leaners can be converted t o Bowden's design by r e t r o f i t t i n g key components.

However, Bowden's newly designed machines overcome p r i o r

Addi ti onal l y , ex i s t i ng aqueous

INFORMAT ION SUPPL IEO

BY

BOWDEN INDUSTRIES