The document discusses an automatic control system implemented at Design and Manufacturing Corp. to control their porcelain pickling operations. The system uses Parker Chemical's Reactitroller control systems to monitor and control chemical concentrations and temperatures across multiple stages. Since implementation, the system has reduced rejects by 40%, eliminated black spot rejects by 80%, and is expected to meet further objectives with additional controls. Both Routzahn and Simpson remark that the automatic system provides consistent process control and has improved quality and reduced costs.

1. Effective Automatic control systems for porcelain
Pickling Operations
JEFFREvP. RourzaHN
Design and ManufacturingCorp.
2000 North Illinois Ave.
C o n n e r s v i l l eI.N 4 7 3 3 1
Jnrr SrupsoN
Parker ChemicalCo.
32 100 StephensonHwy.
Madison Heights, MI 48071
Metal preparation operationsare described.Stepstaken to automatically control
each stage are explained.Benefits that haue risulted are discussed.
Mr. Routzahn's Remarks:
p esignand Manufacturing corp., manufacturer home dishwashers,
of begana
program in the middle to reducepickle-related rejectsfrom its porcelain
9f ]981
e n a m e l i n g p e r a t i o nE a r l y i n l 9 g 4 w e h a c o u r ' , g o o d " d a y sa n do u r . , b i d ' ,
o . l days
andcouldonly associate with the controlof our picklesystem.Tighter
it parameters
for eachtank were established tankswere tobe kepiwithin tlieseparameters.
anci
As this programwas setup, we gaveonly the superintendent the porcelain of rine
the authorityto changetheseparameter.s.
once the new parameters had beeninstitutedin the summerof 19g4.we found
some improvement but still ha<t problemsrelatedto the pickling process. we As
analyzed situation, discovered still hadchemical;.spikes;''into system.
the we we the
Thesespikes,we felt, causedmuch of the inconsistencies our pickle ,yrt"-. in
To solvethis problem,in January1985we installed chemicalp."-i^ systems and
chemicalmeteringpumps to our pickle line. Although we now felt that we had
againimprovedour operation,we still had an inconslstent concentration level in
our pickle system.As our operators had done standard titration methodshourly
for years, we felt that they were doing all they could do manually to control the
system.
By March 1985 we beganinvestigating feasibilityfor automaticcontrol
the
systems utilizing Parker Chemicalcompany's "Reactitroller,' control systems.
we were impressed with their equipmentof this type for other applications and
felt it had the potential to offer us the control we needed.
An internalpriority plan was developed the puchase for and implementation
of a seriesof dual-stage Reactitrollers. The objectivefor the controi sysremwas
to provideconsistent process stage control throughout pickle process.
the consis-
tent process control would, we felt, ( | ) eliminateor drasticallyreducepickle-related
Jeffrey P. Routzahn is a chemical process engineer with D_esign and Manufacturing corp. and
is responsible for overall chemical processesin the plant. He i3 a graduate r]
i;li;nu Univ. and
has been with D&M since 1978.
J-effSimpson is the engineering_-services
director at Parker Chemical Co. He has been rvith parker
chemical for over 20 vr, hokiing various positi.ni itt'sares una -ur,ue";;nt.--*'
JJJ

2. "black spots", (2) provide more uniform ware for better process
rejects, such as
flexibility, and (3) improve productivityby reducingchemicalcosts,operatlngcosts
and maintenancecosts.
Our prioritized project stepsrevolvedaroundthe sequential installationoffour
dual-stagi Reactitrollers.The complete success the first led to the installation
of
of the second,and so on. For example, the first control unit maintainsboth our
nickel rinse and neutralizer stageswithin very tight control ranges.
Even thoughthe project is only 75% complete, feel that the objectives
we have
already been met. The results are:
(1) Tightened control of concentrationrangesin formerly troublesomeproc-
ess steps.
(2) Overall reject rate reduced40%.
(3) Black spot rejectsreduced80%.
(4) lO0% eliminationof ware streakage.
(5) Second-pass rejectsreduced50%.
(6) Troublesomerusty plume 100% eliminated'
(7) Chemicaland overall processcosts reducedsignificantly.
We are now controlling the various stages our cleanerconcentration,
of ferric
percentage,sulfuric acid percentage,nickel pH, nickel rinse concentration,and
neutralizerconcentration(Table l). The full project objectiveswill be met in the
near future by the addition of:
(l) Full temperature monitor and alarm system,
(2) Stage 6 ferric pH control,
(3) Stage l0 nickel concentrationcontrol, and
(4) Evaluationof full rinse contamination "auto-drain" monitor
control via an
from Parker Chemical.
In summary,the installation and implementation an automatic
of control system
for our porcelain pickling operation is an unqualified success.The final project
steps are small and should present no problem.
Mr. Simpson's Remarks
Our companyis a supplierof automaticcontrol systems improve the results to
obtainedwhen using chemicals. Our systems cover a considerablerangeof features
anclcapabilities.At Design and ManufacturingCorp. the Dual-StageReactitroller
was chosenin order to be compatiblewith the step-wise implementation plan' while
providing the necessaryfeatures listed below:
(l) Complete sensingand feedbackcontrol for two analoginputs.
(2) Continuousrecordingof both inputs.
(3) High and low alarms with warning beacon for each input, alarm
acknowledeewith auto reset.
(4) Semi-automaticback-up operating mode.
(5) Flexible and durable sensorsystem.
(6) Transmitters with meter display to provide for remote location of the
controller.
(7) Secondarytimed output for each channel.
(8) NEMA 12 construction, with doubledoor, plexiglass window, limited ac-
c e s s ,a n d e a s eo f i n s t a l l a t i o n n d m a i n l e n a n c e .
a
In addition, the systemhas adjustable sensitivityand provides for temperature
compensation.In order to have sufficient accuracy, the input from each sensor
provides for individual ranging and scaling. Units are designedto facilitate field
service;components may be removedand replacedon-sitein almost all cases.All
334

3. components selected the basisof reliability; only heavyduty industrialgrade
are on
are used.The choiceof sensors especially is critical to the satisfactoryoperation
ofthe systems. Sensors specified
are basedon the particularprocess and concen-
trationto be used.Based general on experience electrodeless
the conductivity sen-
sor system the mostcommonlyusedof all sensor
is choices. This approach very
is
sensitive chemicalchangesin the processbath.
to
With the Designand Manufacturing installation, this designappears have
to
been successful.Other customersmight require a different approach. The next
model,Reactitrollers, combines the features
all notedabove,for up to nine stages.
in singlecentralcontrol cabinet.As the number of control points increases, the
Reactitrollerbecomesmore cost effective. Due to the large number of stages con-
trolled, the logic requirements sufficientto warranta programmable
are controller.
In addition,the individualstrip-chart recorders replaced a singlemulti-point
are by
programmable recorder.This centralized control systemalso providesfbr addi-
tional intra-stage functionssuch as counterflowand sequence alarming.
Further, there are those instances where even larger centralizedsystemsare
required. These systems,called Reactitroller/8O are actually processcontrol
systems. They are capable not only controllingthe chemical
of concentrations, but
rnonitoringand alarmingany conditionwhich could affect the quality or cost of
the process.Thesecontrollersincorporate the use of larger programmable con-
trollers with analogcapabilityin order to handlethe greatly increased logic re-
quirements and in order to be able to communicate with other computers.
Whatevertype of control systemis selected, questionof how to justify
the
the cost and installation this new equipmentis alwaysof concernto the customer.
of
I think now that D & M would agrec that the equipmenthas been an excellent
investment, althoughat the time it was not as clear. In any case,thereare certain
broad areaswhich the prospective user shouldvalue relativeto their own opera-
tion in order to justifu the purchase a chemicalor process
of control system.To-
day's usersof chemicals have displayed interest adapting
an in automatic control
systems. This interesthas been driven by the desireto improve quality. and to
u l e s s e r x t e n tt o c o n t r o lc o s t s .
e
As U.S. manufacturers becomemore concerned with the overall quality of
their productand beginto apply statistical qualitycontrolprinciples their opera-
to
tions, it soon becomes evidentthat it is very difficult, if not impossible, con- to
sistently maintaineachof the stages a complexmodernwasherwithin optimum
of
rangesof concentration, temperature, and level or volume. In addition,solution
flow, pressure, evenmaintenance conditionof the mechanical equipment con-
are
stantly fluctuating and should be monitored. These are all critical parametersto
the cleaningand treatment processand any variationcould result in an adverse
changein the final product'squality or cost of operation.
Various auditsrun on customerlines have shownthat in generala manually
operatedsystemis statistically oniy about52% capable maintainingthe optimum
of
concentration a typical treatmentstage.When takeninto consideration
of that there
are a number of other stages,each respondingto various independent and inter-
relatedfactors,the statistical probabilitythat the entirewasheris at any one time
operatingat optimum is very low. In a few casesthe culminationof the above
factorscan be demonstrated the reductionin number of rework jobs or rejected
by
parts. More difficult to ascertain field failures,customer
are dissatisfaction, per-
centof re-buy,and ultimatelymarketsharechange. There is no doubt that quality
is dependent knowing and controllingthe relevantmanufacturing
on processes,
which. in the critical area of the washer meanschemicalcontrol.
335

4. ThesecondmajorpointofjustificationforachemicalcontrolSystemisreduc-
be evaluatedby the
tion in overall operating cost;' The following areas must
(3) water treatmentcost reduc-
customer:(1) chemicalslavings, water savings,
(2)
(6) maintenance savrngs'
tion, (4) energycost savings'(5) manpowerutilization'
and (7) safety imProvements. "1ym^berof months
it ur, on" rnuit look beyond the old accountingmethods.of
.opuvuu.r.'';alsotheareasofimportance..willdifferconsiderablyfromoneuser
pretreatment
to it " n"*t. Certainly one of the most significantchanges the_metal
in
area in the last sev-eral years has beei the increasing use of automatic control
will be
;i;;.;r, we believe thai this rrend will continue, and that these systems
utilized in an increasingnumber of industries, such as the porcelain enameling
industry.
336

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