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Патент USA US3091568

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May 28, 1963
E. SHAY
3,091,558
METHOD OF‘ PICKLING
Original Filed 001:. 30, 1957
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INVENTOR
Eli Shay
May 28, 1963
E. SHAY
3,091,558
METHOD OF PICKLING
Original Filed Oct. 30, 1957
2 Sheets-Sheet 2
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INVENTOR
Eli Shay
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United States Patent 0 "
2
11
by the product area rate of passage through the pickling
tank may be determined. I prefer to provide product
speed measuring means, pickling agent control means in
connection therewith and pickling agent gauge means
whereby the rate of ?ow of the pickling agent may be de
termined for further adjustment of said ?ow. I ‘further
3,091,558
METHOD OF PICKLING
Eli Shay, Warren, Ohio, assignor to The Wean Engineer
Company, Inc., Warren, Ohio, a corporation of
10
Original application Oct. 30, 1957, Ser. No. 693,369, new
Patent No. 3,000,385, dated Sept. 19, 1961. Divided
and this application Sept. 30, 1960, Ser. No. 59,531
.3 Claims. (Cl. 134-15)
3,091,558
Patented May 28, 1963
preferably provide control means for a dilutent in opera
tive connection with the pickling agent control means
whereby the dilutent may ‘be introduced into the pickling
10 tank proportionally with the pickling agent.
This invention relates to the cleaning of products of sub
stantial length by passing them in a substantially continu
1Other details, objects, and advantages of the invention
will become apparent as the following description of a
present preferred embodiment thereof proceeds.
‘In the accompanying drawing, I have illustrated a
This application is a division of my co-pending applica
tion Serial Number 693,369, ?led October 30, 1957, now 15 present preferred embodiment of my invention in which
FIGURE 1 is a diagrammatic view showing a portion
‘Patent No. 3,000,385 .
of a pickling tank with the associated controls being
In the treatment and fabrication of many products of
shown diagrammatically, and
extended length, such as ferrous strip and wire products,
FIGURE 2 is a side view of the exit end of acon-ven
for example, it is frequently necessary that the products be
cleaned prior to performing a particular operation upon V20 tional pickle line embodying the invention, showing a por
ous manner through a pickling tank.
them.
The cleaning process may be acid or alkaline and
is generally known as pickling. Speaking by way of ilus
'tration, hot rolled steel strip is ordinarily covered with mill
scale of ferrous oxides resulting from its exposure to air
‘at elevated temperatures. The scale must be removed 25
prior to cold rolling to avoid inclusions of scale in the cold
rolled strip. The strip is, therefore, passed through a
tank containing an acid pickling solution. The problems
of handling the strip at either end of the pickling tank, of
‘Welding coils to form a continuous strip before pickling, 30
and of cutting the strip into manageable lengths after
pickling, may reduce the strip speed in the pickling tank
below the usual opera-ting speed or require that the line be
tion of the pickling tank, the pinch rolls which pull strip
through the pickling line and the strip washing and dry
ing apparatus positioned between the pickling tank and
pinch rolls.
In the accompanying drawing, a pickling tank is illus
trated which is suitable for acid pickling of hot rolled
‘strip prior to cold rolling. The handling of such strip is
generally well-known. ‘ A particular type of installation is
‘shown, for example, in United States Patent 2,196,600 to
Raymond J. Wean and Donald A. McArthur. A portion
of a pickling tank 1 is shown diagrammatically. The strip
passes into the pickling tank at irregular speeds because of
normal operating conditions. The strip is pulled from the
tank between a pair of conventional pinch rolls in a con
stopped momentarily. Despite such variations in speed
and stops, the process is substantially a continuous one in 35 tinuous operation, although the speed varies widely, and
the strip may even be stopped at times. 1One of the pinch
which the product moves through the tank as an endless
rolls is illustrated at 2 and has a tachometer generator con
member approximating a predetermined speed.
nected to it. The pinch roll is continuously in contact
It is necessary for e?icient operation to add acid and
with the strip whereby it and the connected generator will
water continuously to the pickling bath to maintain a
proper concentration of acid and iron in the bath for opti 40 rotate at a speed proportional to the strip speed,’ produc
ing ‘a proportional elect-ric' signal. The signal is trans
mum removal of the mill scale from the product. !Here
mitted on wires 4 to a transmitter 5 which will deliver-air
tofore, acid and water have been added at a predetermined
to a pipe ‘6 at a pressure proportional to the generated
rate calculated from the average speed and width of strip
voltage. A Foxboro E.M.F./pneumatic transmitter is a
‘passing through the pickling tank. Hourly or more fre
quent titrations have been necessary to check the acid con 45 satisfactory instrument for this purpose. LA. manually set
valve 7 supplies a regulated amount of air to a pipe 8.
centration in the tank and to make ?ne adjustments in the
The valve supplies air at a reduced pressure which is pro
.acid and water flow, in accord with the results of the titra
portional to the opening of the valve, and is calibrated in
tions. Regular corrections in the rate of acid and water
inches of strip width. Thus, by appropriate setting of
?ow have been necessary, and it has generally been nec
essary to overcorrect for the purpose of reto-ring a proper 60 valve 7, an air pressure in pipey8 is maintained which is
proportional to the strip width. A Foxboro pneumatic
balance. To provide against insu?icient pickling, an ex
airdron type 20 supply regulator is suitable at this point.
cess of acid has normally been carried resulting in a waste
A multiplier 9 multiplies the pressures in pipes 6 and 8
of acid and acid attacks on the product after removal of
and transmits a resultant pressure in pipe .10. Conse
the scale. Regardless of the particular product being
pickled, certain problems will usually be present in some 55 quently, the pressure in pipe 10 will be proportional to
the area of strip passing through and leaving the pickling
degree. The ?ow of the pickling agent must be controlled
tank. A Foxboro M/40 ‘black box computer is a satis
to maintain a su?icient concentration for complete pick
factory instrument for these purposes. A recorder '11 of
ling, while holding attacks on the metal to a minimum.
conventional design vcontinuously records the pressures in
The maintenance of optimum conditions in the pickling
tank reduces the amount of waste product which must be 00 pipes 6 and "8 on a chart to make a permanent record, as
well as to ‘give visual indication of the pressures at any
disposed of, and is highly desirable for this reason alone,
the disposal of pickling waste being a major operating
problem.
moment.
Sulfuric acid used for pickling is maintained in a head
I provide means for continuously pickling a product 65 tank 12 and feeds through ‘a supply pipe 13 into the pick
ling tank at a discharge point 14. Pipe 10 leads to a con
comprising a pickling tank through which the product is
troller 15 which transmits the pressure through the pipe
passed, product measuring means to continuously measure
16 to valve 17 in acid supply pipe 13. Valve '17 opens an
the rate at which the product passes through the tank and
amount proportional to the air pressure in pipe 116, there
control means to introduce a pickling agent into the tank
‘at a rate proportional to the rate of passage of product 70 by allowing acid to pass into the pickling tank in an
amount proportional to the area of strip then passing into
through the tank. I prefer to provide product speed meas
the pickling tank. A Foxboro stabil?o wide range con
uring means and means to indicate the product size where
3,091,558
4
3
water flow ‘control valve.
trolvalve is suitable for this purpose. A solenoid valve .19
is normally maintained in open position but may be op
manually to suit the particular operating conditions.
Once set, this ratio is ordinarily maintained constant for
given operating conditions, and future adjustments are
made only infrequently. The amount of acid supplied
erated to close pipe 16, thereby stopping acid ?ow into the
tank. \It will be apparent that small ‘variations in the acid
?ow‘ may ‘occur due to variations of level in head tank
1,2,v inaccuracies in valve and instrument settings, and the
may be cut off or increased through manual control to
meet abnormal operating conditions or make corrections
in the acid concentration if necessary. It has been found
that the desired acid concentration is maintained much
more closely than is possible with manual control. The
time between titrations of the pickling tank solution has
like. A- magnetic ?ow meter 20, such as that employed
in - a Foxborov magnetic ?ow control meter system, is
placed in acid supply pipe 13. The ?ow meter measures
the rate of ?ow of acid in supply pipe 13 and transmits a
proportional electrical signal through wires 21. to a con
been increased, thereby reducing the labor required.
Overly strong acid solutions are avoided,_ thereby making
troller 15 such ‘as a Foxboro dynalog electronic indicating
controller transmitter with stabilog control mechanism,
Model No. 9653—44—48. By-pass valves 18' are provided
around valve 17 and flow meter 20 for manual and emer
The acid-water ratio is adjusted
more effective use of the acid and minimizing acid attack
It will be apparent that use of the in
vention is not limited to wide thin strip or any other prod
15 on the product.
gency operation.
Controller 15 is responsive ‘to the voltage in wires 21.
It thenmodulates- the pressure in pipe 16 to maintain an
uct, that it may be used with products of other types and
cross sections, such as wire, for example, and that any de
accurate ?ow in supply pipe 713 which is proportional to
sired pickling agent may be employed.
While I have illustrated and described a present prefer
actual acid input continuously and to match it accurately
red embodiment of my invention, it is to be understood
that I do not limit myself thereto and that the invention
to the signal indicating the rate of strip passage through
may be otherwise variously practiced within the scope of
tank 1. Controller 15 also records the actual flow of acid
the following claims.
in supply pipe 13 on a chart and transmits in pipe 22 a
I claim:
pressure proportional to the actual ?ow of acid in the 25
1. The method of pickling a product of ‘great length
supply pipe ‘13. A dial type recorder 23 such as a Fox
which passes. continuously through a pickling tank at vari~
boro integrating recorder maintains a record of the total
able speeds, which method comprises measuring the rate
amount of acid discharged into tank .1.
at which the product passes through the tank, determining
A proportioning controller 24 is connected to pipe 22
therefrom the area rate of passage of product through the
and delivers a controlled air pressure in pipe 25 which is
tank, and continuously discharging into-the tank a pick
proportional'to the pressure in pipe 22. The ratio or pro—
the pressure in pipe 111.
This feedback serves to check the 20
portion may be manually set on controller 24.
A Fox
ling agent in amounts proportional to the area rate of
passage of product through the tank.
boro recording receiver ratio controllerflype M/40' stabi
2. The method. of pickling a ferrous product of sub
log is suitable for this purpose. iAir pressure in pipe 25
opens a pneumatic valve 26 proportionally, thereby dis 35 stantial length which is passed, into a pickling tank at vary
charging water through pipe 27 intothe pickling tank at
ing speeds which comprises continuously measuring the
discharge point 28. A flow meter 29‘ connected across an
ori?ce ~30, records'the actual ?ow of water in pipe 27.
speed of passage of the ferrous product through the tank,
determining therefrom the area rate of product passing
through the tank, discharging an acid into the tank pro
Manual by-passes 31 are provided around the valve 26 and
ori?ce 30. The flow meter develops an air pressure in 40 portionally to the area rate of passage of ferrous product,
and discharging water into the tank proportionally to the
pipe 32 proportional tothe actual flow of water through
rate of introduction of acid.
ori?ce 30. Pipe 32 connects to a proportioning controller
3. The method of pickling a product of‘ substantial
34 such as a Foxboro indicating ?ow transmitter and
serves as a feedbackfrom which controller 24 further ad
length which is passed intoa pickling tank at varying
justs valve 26' to maintain a correct flow of water in pipe
27. A dial‘ typefrecorder 313, such as a Foxboro pneu
speeds which comprises continuously measuring the speed
of passage of the product through the tank, determining
therefrom the area rate of product passing through the
tank, discharging an alkali into the tank proportionally
tothe' area rate of passage of said product, and discharg
pickling tank- 1.
. 50 ing Water into the tank-proportionally to the rate of intro
‘From the foregoing, it will be apparent that the area of
duction of alkali.
,
matic receiver integrator, records the total gallons of water
discharged into the pickling tank. Two pens in controller
24 continuously record the flow of acid and of water into
strip passing through the pickling tank is ‘constantly be
ing' determined and that acid is delivered to the pickling
tankv in a ?xed proportion thereto. The actual flow of
acid is measured, and this information is fed back to the 55
controller for further precise adjustment of the acid ?ow
control valve. In like manner, water is supplied to the
pickling tank in an amount proportional to the acid ?ow.
Similarly, the actual water flow, is measured and fed back
to the water ?ow controller for further adjustment of the 60
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,235,658
Waterman ___+ _______ __ vMar. 18, 1941
2,769,735
(Miller ____ __i ________ __ Nov. 6,
1956
2,927,871
Mancke ______________ _ Mar. 8,
1960
2,956,905
Jones ___________ __- ____ __ Oct. 18, 1960
2,994,328
Lewis ________________ .. Aug. 1, '1961
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