Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
O84
APPARATUS AND METHOD FOR DETECTING FOULED
COOLING CIRCUITS IN A BLAST FURNACE OR THE LIKE
Background of The Invention
. .
The present invention pertains to an apparatus and method
for determining which, if any, cooling circuits in a blast furnace
or similar device have become fouled or plugged.
The ultimate life and total performance of an iron making
blast furnace are dependent on the ability of the furnace refractory
to withstand the extreme operating conditions of high gas tempera-
; 10 ture and abrasive charge materials. Unfortunately, furnace refrac-
tories have a limited life. Aside from mechanical abrasive effects,
degradation or solution rate of most refractories is dependent on
the refractory temperature itself. Generally, as refractory tem-
perature increases, so does the solution rate.
.
In order to decrease high temperature effects on the blast
furnace refractory and to provide structural integrity, cooling
water stack systems have been incorporated into most blast furnace
~ designs. It is typical for these furnaces to have a matrix of cop-per stack plates embedded in the refractory stack walls to supply
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the necessary cooling. Each individual cooling circui t normally has
an upstream end and a downstream end and includes about 10 or less
of these stack plates. Most blast furnace cooling circuits utilize
once-through water systems and are diagonally or horizontally dis-
posed about the furnace. Commonly, about 80 - 150 of such circuits
are provided about the furnace. Water supply is usually off a corn-
s mon header with each circuit having its own discharge into an open
trough surrounding the furnace.
Various cooling system monitoring means have been designed
to monitor varying operating parameters of the cooling circuits.
For instance, in U.S. Patent 3,652,070 (Sagara), there is disclosed
an apparatus wherein a temperature sensing means extends within the
refractory itself, and is associated with control means to regulate
the passage of cooling fluid through the refractory medium to there-
by control the adhesion of fused slag to the refractory.
In U.S. Patent 4,188,021 (Patuzzi, et al) entitled "Metal-
lurgical Vessel Cooling and Safety System" an emergency drainage
system is disclosed, the intent of which is to provide for the dump-
ing of cooling fluid during an upset to prevent equipment and/or
personal damages. Of similar import is U.S. Patent 4,133,373 (Slagley
et al) which discloses a leak detecting apparatus for a blast fur-
nace cooling system.
Althouth the above-noted cooling system monitoring means
are known in the art, to our knowledge, no one has yet devised a
portable, hand-held assembly that provides an easy and convenient
means for ascertaining if certain circuits in the blast furnace have
become clogged or fouled. As is well-known, clogging or fouling of
these cooling circuits impedes the desired heat transfer function of
the cooling system, leading to decreased refractory life. Moreover,
although various chemical additives may be added to these systems,
to minimize deposition and fouling of the cooling circuits, it is
highly desirable to provide a means which is capable of gauging the
efficacy of these chemical additives.
These and other objects are achieved by the apparatus and
methods disclosed herein.
Summary of The Invention
The present invention provides a convenient hand-held
portable device which can be used to measure the flow rate and
temperature on the open-ended discharge pipes of a blast furnace
cooling circuit line or lines. By the use of the above two para-
meters, in addition to measurement of the influent cooling fluid
temperature, the heat flux for each cooling line may be calculated,
with the data allowing the observer to render certain judgments
regarding the cooling circuit performance of individual circuits or
the entire furnace in general.
,
A measured decrease in flow, temperature, or heat flux
from a predetermined value will generally indicate a problem such as
: circuit pluggage or fouling. An increase in these parameters, over
the predetermined value, is generally indicative of reduced pluggage
or scale removal. It is thus apparent that this data is useful in
monitoring the efficacy of any chemical additives that may have been
- 25 admitted to the cooling system for the purpose of controlling
' deposits.
il~78~84
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Briefly, the apparatus comprises a first conduit that de-
fines a first flow passage for the cooling liquid when the device
is connected to the discharge end of a particular cooling circuit.
A thermocouple or the like is disposed in this first flow passage to
measure the temperature of the cooling fluid flowing therethrough.
This thermocouple, or similar temperature sensing device, may be
associated with a digital LED readout display so that the user may
immediately read and record the discharge temperature of the parti-
cular cooling circuit line.
A flow meter is also operatively connected to the first
flow passage to measure the cooling fluid flow at the discharge
end of the cooling circuit. Preferably, a by-pass conduit means is
also part of the integral, hand portable equipment, so that, when
the device is initially connected to the cooling circuit, back pres-
sure may be relieved thereby. Also, use of the by-pass conduit
means at initial hook-up time prevents damage to the temperature
sensing device and flow meter that may otherwise occur.
Drawing
The invention shall now be illustrated in further detail
in the following detailed description and the appended drawing in
which:
Figure 1 is a schematic drawing illustrating the preferred
embodiment of the blast furnace cooling circuit fouling detection
device of the present invention.
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Detailed Description
With respect to the drawing, therein shown is the fouling
detection device of the present invention. Rachet handle 1 con-
nected to clamp means 5 through linkage members 2, 3, and 4, serves
to provide a convenient means of attaching the device to the dis-
charge end of the desired blast furnace cooling circuit line.
Hose member 6 is provided with another clamp 19 to aid in
securing the device to the cooling circuit line. Adaptors 7, 8
connect hose 6 to "Y" pipe 9. The downstream end of "Y" pipe 9 is
threadably engaged to piping 10, which, in turn, is secured to
manually operable on-off socket valve member 11. At the downstream
end of valve 11, adaptor 20 and hose member 21 are serially con-
nected.
At one Juncture of "Y" pipe 9 is provided pipe 22,
threadably secured to member 9. Pipe 22 is secured in fluid tight
relation with one Juncture of "Y" pipe 25. The upstream end of "Y"
pipe 25 is connected to reducer bushings 14, 15 through female
adaptor 26. The upstream end of bushing 15 is, in turn, connected
to compression fittings 16, 17. Extending within the flow passage
from atop fitting 17, is thermocouple member 18. This member is
designed to measure the temperature of the cooling fluid as it flows
through the device. We have found that a "K" type thermocouple best
serves the intended function of the device, al~hough it is noted
that other equivalent temperature sensing means may suitably be
employed.
11~7~08~
For convenience of the user, the thermocouple may be con-
nected to any one of a number of digital readout devices (not
shown). One such LED readout device is manufactured by Omega Engi-
neering, Stamford, Connecticut.
.j ,
Threadably engaged to the downstream end of "Y" pipe 25
is pipe member 24, which, in turn, is connected to male adaptor 13.
.
Flow meter 12 is secured to the downstream edge of adaptor
13. Preferably, the flow meter 12 is of the type, known in the art,
which operates by a mechanical differential pressure method. In
this method, differential pressure, produced by fluid flow through a
calibrated flow nozzle, is sensed by an arrangement of opposed bel-
lows. Displacement of the bellows is transferred by a low-friction
cam and lever to a rotary geared movement to indicate flow rate
directly on the dial shown in the drawing. Operation of the depic-
ted flow meter 12 is completely mechanical, with no electrical con-
nections being required for operation. One such flow meter, pres-
ently preferred, is made by RCM Industries of Orinda, California.
It is, of course, to be noted that those skilled in the art will be
capable of utilizing other types Or flow meters in conjunction with
the inventive ideas herein disclosed and claimed. All such
equivalent flow measuring devices are deemed to be within the spirit
and scope of the present invention.
A first flow passage is defined by members 6, 9, 22, 25,
24, 13, 12, and 23. During passage through this first flow passage,
temperature and flow rate of the cooling fluid may be measured.
When, valve 11 is in the "open" position, fluid flow is diverted
from the first flow passage and instead is caused to flow through a
second flow passage, defined by members 9, 20, and 21. This "di-
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verting" structure has proven quite helpful, especially when the
device is first connected to the discharge end of the desired cool-
ing line circuit. In this way, back-pressure problems which may
cause spraying of the cooling fluid on the user and/or flow meter
5 and thermocouple damage are minimized.
It thus becomes apparent that the device is used to detect
fouled or plugged cooling circuits of the blast furnace cooling sys-
tem. In this respect, data generated from the device is recorded
along with the temperature of the influent cooling fluid. Heat flux
10 for a particular circuit or for all circuits may then be calculated
according to:
Q = MCp ~t
wherein Q = heat flux, btu's per hour; M = mass water flow, lbs per
r hour at discharge; Cp = specific heat of fluid, btu's per lb. per
15 F (Note: water is approximately 1 btu per lb per F); ~ t = tempera-
ture difference between influent and discharge in F.
i
Predetermined optimal or normal values may be determined
by recording the above parameters for a given circuit or circuits
over a given period of time, or predetermined optimal values may be
determined by averaging heat flux figures for all circuits, with
heat flux values for particular circuits falling below this value
being possibly indicative of abnormal circuit pluggage, etc.
As is now apparent, a decrease in flow, temperature or
heat flux, from the predetermined value, could indicate such prob-
c
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lems as pluggage or fouling. An increase in these parameters mayindicate reduced pluggage or scale removal. This method ~ay be thus
used as a means of gauging the efficacy of certain chemical addi-
tives which are added to the system for the purpose of minimizing
deposition and fouling.
Although use of the above device and method are especially
well suited for monitoring once-through cooling systems, they may
also be adapted to monitor open recirculating systems where there is
a discharge of cooling fluid into a reservoir or the like. The
invention may also be used in connection with normally closed recir-
culating systems, if some type of by-pass discharge plumbing is
present.
The foregoing detailed description has been given for
clearness of understanding only and no unnecessary limitations
should be understood therefrom as modifications will be obvious to
those skilled in the art.
