External sludge collector for boiler bottom blowdown and automatic blowdown control initiated by conductivity probe within the boiler and method

An improved electromagnetic boiler water conditioning apparatus and method for energy saving, comprising an electromagnetic water treatment unit combined with an external sludge collector attached to the boiler for boiler bottom blowdown by means of a solenoid valve controlled by a conductivity probe within the boiler. The probe is electrically connected to the solenoid blowdown valve. The blowdown is initiated by the conductivity probe whenever the dissolved solids within the boiler as a result of evaporation become too high. The external sludge collector permits unimpeded removal of sludge formed in the boiler passing into the collector and is a straight pipe having a diameter of about 21/2 to 4 times, preferably 3 times, the diameter of the standard openings at the bottom of the boiler. The level of the water to the boiler is maintained by an automatic level control which can also be cleaned through the sludge collector. The invention contemplates inclusion of a turbidimeter at the end of the external sludge pipe to independently check suspended solids. The electromagnetic unit which is of unique value in the present combination for saving energy is that using seven propeller flights disclosed in my application Serial No. 153,219, filed May 17, 1980, now U.S. Patent No. 4,288,323

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention is in the field of an electromagnetic water treatment device 
as disclosed in my U.S. Pat. No. 4,151,090 granted on Apr. 24, 1979, and 
my U.S. Pat. No. 4,148,731 granted on April 10, 1979. 
This invention is in the field of liquid heaters, boilers and vaporizers 
which are provided with a cleaning means and in particular cleaning means 
in which pneumatic pressure for the purpose of separating suspended solids 
which collect at the bottom of the liquid heater or boiler. 
This invention is in the field of testing the liquid suspension of solids 
and in improved electrical control circuits for such testing in order to 
initiate automatic blowdown of predetermined quantities of solids. 
This invention also relates to low cost apparatus for the physical 
treatment of boiler water at elevated temperatures which includes as a 
critical step in such physical treatment the electromagnetic treatment of 
all incoming feed water to the boiler whereby suspended solids and 
dissolved solids in the water which is in an incipient state of 
precipitation can be safely removed physically by blowdown procedures in 
predetermined quantities and for predetermined times. 
2. Description of the Prior Art 
In the prior art of cleaning boilers by blowdown procedures water treating 
chemicals have been fed into the boiler and the treated water has been 
removed by blowdown devices, an example of said chemical treatment being 
Rivers U.S. Pat. No. 3,139,071. The chemical treatment in this patent 
requires the provision of a reservoir for the chemical, a pump, a filter, 
accurate records for the amounts employed and close supervision. Another 
example of a blowdown system employing chemicals to treat the water is 
found in Anderson U.S. Pat. No. 3,908,605. Anderson provides automatic 
operation and uses a conductivity sensor model which facilitates blowdown 
at low or at high pressures. Indeed, the Anderson system permits optional 
surface blow for removal of froth which accumulates in chemical treatment. 
One of the difficulties with the Anderson system is its high cost, despite 
the fact that the energy savings are significant. It is recognized that 
energy costs for fuel are very substantially affected by the scale 
thickness within the boiler. Tables and graphs provided by the EPA have 
demonstrated that 8% of the fuel bill is wasted, for a 100 horsepower 
boiler operating every day for the entire year at 85.cent. per gallon, oil 
cost would add $18,466.00 to the bill. If the scale thickness increases to 
7/64" then the extra oil cost is $46,165.00. Faced with these fuel costs 
it is not at all surprising to find that substantial investments are made 
in chemicals for water treatment within the boiler, for devices to dose 
these chemicals and for personnel to carefully watch this treatment. 
The present invention provides an advantage over the Anderson system in his 
U.S. Pat. No. 3,908,605 by changing the location of the probe to within 
the boiler as is done in the nuclear energy steam plants and by providing 
a novel external straight line sludge collector having an enlarged 
diameter, two to four times the diameter of the standard opening at the 
base of the boiler whereby the sludge removed by outside blowdown avoids 
excessive turbulence within the boiler following automatic blowdown 
procedures, causing resuspension of the sludge resulting from inner 
blowdown. 
Other prior art is known for automatic blowdown. For example, Holdt U.S. 
Pat. No. 3,680,531 in which a monitoring system is used for repeating the 
sampling at fifteen minute intervals in an automatic blowdown system. The 
present invention distinguishes over this Holdt patent in providing 
controls for the electromagnetic unit and for the sensor probe on a common 
panel so that there can be assurance that all physical treatment systems 
are operative. This not only improves the efficiency of the system but 
lowers the cost. Two panels are more costly than a single panel. 
Electrical costs are cut because the rectifier circuit for 24 volt DC 
current energizes the probe for sensing total dissolved solids and also 
energizes the electromagnet in the electromagnetic water conditioning 
unit. 
Courvoisier et al U.S. Pat. No. 3,552,189 granted Jan. 5, 1971, assigned to 
the French Atomic Energy Commission discloses a monitoring apparatus to 
detect the imminent danger of scale formation on a surface for transfer of 
heat between scale forming liquid and the liquid in the form of vapor 
before deposit has begun to form. Courvoisier et al points out that large 
boilers used in the atomic energy field are very expensive and it is 
essential that they remain efficient in order to prevent irreparable 
damage to the boiler as well as costly chemical or mechanical cleaning of 
the surface after scale has formed. Although Courvoisier et al are 
familiar with boiler systems for the prevention of scale they recognize 
that for desalination of sea water by distillation that the formation of 
salt deposits is one of the most important problems to be overcome. As 
stated by Courvoisier et al, "the deposits which are formed increase at 
such a high rate that, when a drop in efficiency is observed as a result 
of such deposits, it is already too late to modify the conditions of 
operation of the plant (temperature, concentration factor, hydrodynamic 
parameters). It is therefore necessary to stop production in order to 
carry out either chemical or mechanical cleaning of the surfaces." The 
present invention is useful for the same purposes of Courvoisier et al but 
relies upon electromagnetic treatment to prevent scale deposits from 
adhering to the metal surface and utilizes in combination with the 
electromagnetic treatment, particularly in applicant's prior application 
Ser. No. 153,219 filed May 27, 1980, now U.S. Pat. No. 4,288,323, an 
external sludge collector in the form of a straight pipe with a diameter 
about three times as great as the diameter of the standard opening at the 
bottom of the boiler. As a direct result of the electromagnetic treatment, 
the deposited salt is formed as a nonadhering mass and can readily be 
removed by automatic bottom blowdown procedure from a location outside of 
the boiler. 
I am also aware of the patent to Dallimonti, granted Jan. 4, 1977, assigned 
to Honeywell, Inc. of Minneapolis, Minnesota, which relates to a console 
cathode-ray digital display and control system which is especially adapted 
for large municipal water, sewage and steam systems. These industrial 
plants and particularly those which are used for automatic energy and 
boiling water reactors are benefited by digital display and control 
consoles on which are mounted a number of individual process control 
instruments and read-out devices arranged for manipulation and monitoring 
by a human operator to achieve control over the process. The apparatus of 
the present invention is adapted for monitoring within the system of this 
Dallimonti patent. 
OBJECTS OF THE INVENTION 
An object of the invention is to provide an improved apparatus for 
continuous operation of boilers embodying an external sludge collector in 
the form of a straight pipe connected to the two bottom openings, one at 
each end of the pipe of the boiler and further combined with an 
electromagnetic treatment unit as disclosed in my application Ser. No. 
153,219, now U.S. Pat. No. 4,288,323. 
A further object of the invention is to provide an improved low cost 
electromagnetic water boiler conditioning apparatus which saves energy 
wasted in blowing down under automatic sensing control the contents of the 
boiler to prevent the deposition of scale which system is adapted to be 
used without added chemicals for conditioning the water or with added 
chemicals and which controls the blowdown initiation by sensing the total 
dissolved solids during the boiler evaporation operation. 
A further object of the invention is to provide an improved control system 
which is furnished with warning lights and an audible signal whenever the 
concentration of dissolved solids is too high to prevent the unintended 
boiling to dryness and deposition of scale. 
A further object of the invention is to provide an improved bottom blowdown 
system which is operative to eliminate sludge collecting in a novel 
external sludge collector below the boiler, the sludge collector having 
precipitated particles conditioned to be in a nonadherent state by the 
action of the electromagnetic treatment of the module described in my 
application Ser. No. 153,219, now U.S. Pat. No. 4,288,323. 
Further and other objects will be seen from the Summary, Detailed 
Description of the Preferred Embodiments and in the drawings herein. 
SUMMARY OF THE INVENTION 
This invention is directed to an improvement in electromagnetic water 
conditioning apparatus combined with an external sludge collector fitted 
to the bottom of a conventional boiler and further comprising a 
conductivity sensor within the boiler to provide an electrically operated 
sludge valve initiated boiler blowdown at this external sludge collector. 
The invention is based upon the discovery that the electromagnetic water 
conditioning treatment in the apparatus of my prior patent application 
Ser. No. 153,219, filed May 17, 1980, now U.S. Pat. No. 4,288,323, changes 
the feed water in the boiler in such a way that adherent precipitated 
solid particles are not formed inside the boiler tubes and in the walls of 
the boiler. The non-adherent precipitates which form during the normal 
boiler operation move by gravity and through normal currents which are 
operative within the hot liquid boiler so that the particles gather as 
sludge and pass out of the normal bottom openings in the conventional 
boiler. 
The conventional boiler particularly those boilers less than 300 horsepower 
in rating are prone to break down and require frequent scaling treatment 
and chemical treatment because of the generally high hardness of the 
water. In most, if not all, of the states of the United States, there is a 
requirement in law that boilers meet standards of size and performance, 
these standards being the so-called ASTM standards which are uniformly 
followed in the fifty states. Not only do the standards specify the 
critical dimensions of the boiler and boiler openings, they also specify 
the ratings of the valves that are used. Thus, a standard boiler which is 
about five feet high and about twelve feet long has a shell of specified 
thickness, an iron alloy composition for the shell of specified 
composition and the inlet as well as the outlet openings at the top and 
bottom of the boiler are placed at specified locations and are of 
specified diameters. Further there is a uniform boiler and pressure vessel 
code of the ASME provided for the safe operation of boilers. This code 
places the requirements for boiler blowdown from the bottom of the boiler 
as well as from the top and other locations. For this five by twelve 
boiler the opening at the bottom is an inch and one quarter and there are 
two such openings, one near the front and one near the back of the boiler. 
The conventional blowdown operation for boilers which are subjected to 
bottom blowdown for the purpose of intermittent removal of solids in a 
small volume of water from the bottom while fresh makeup water is 
introduced through the water feed is that which is described in Dixon U.S. 
Pat. No. 3,512,507. The bottom opening for the blowdown in Dixon is 
connected to a pipe of the same diameter as the opening. An electrically 
operated valve is provided in a tap line which is connected to the makeup 
water in the tank so that the valve opens when a pump brings water into 
the boiler whereby the water tapped through the straight pipe equals the 
amount of water which comes in through the pump. Dixon's concept is to 
maintain a predetermined amount of solids in the water in the boiler and 
intermittently adding water from the makeup apparatus while tapping water 
in the same proportion in order to prevent the solids from building up in 
the tank. 
The present invention differentiates from Dixon in adding an external 
sludge collector for the solids which tend as a result of the 
electromagnetic treatment only to collect in a non-adherent condition and 
to provide this sludge collecting pipe as a straight pipe between the two 
outlet openings in the bottom of the tank whereby the sludge collector 
traverses substantially the entire horizontal distance between the two 
openings and in parallel with the tank. A critical feature of the sludge 
collector is the diameter which varies from at least two and one-half 
times the diameter of the opening to about four times the diameter of the 
opening but is preferably three times the diameter of the opening. 
A further feature of the invention is a novel dc control panel which 
economizes on the wiring for the dc probe which is used to sense the hot 
water conductivity based upon the use of a common control panel which is 
used to monitor the electromagnetic water treatment unit and specifically 
a magnetic winding for the electromagnetic water control unit. 
Still another feature of the invention is the use of a turbidimeter which 
is mounted in the external sludge collector so that conditions of dirty 
water encountered when a high organic content in the feed water can be 
sensed by this meter. 
It is within the contemplation of the invention to provide a common 
recorder to insure recording of the sensor probe which senses total 
dissolved solids and the turbidimeter. Such common records are known, for 
example, in the Mostofin, et al. U.S. Pat. No. 4,012,278, granted Mar. 15, 
1977, entitled Feed Water and Condensate Sample Analyzer for Power Plants. 
The invention is also directed to a new combination method for a straight 
line electromagnetic path through which all of the feed water to the 
boiler passes under a magnetic field varying between about 900 gauss and 
1,200 gauss, preferably 1,150-1,200 gauss, the magnetic field being a 
constant dc field which surrounds a ferromagnetic tube and all of the 
water passing with turbulence through a passageway between a seven flight 
propeller and the inner wall of the ferromagnetic tube in a thickness of 
about 1/16 of an inch to about 1/64 of an inch, preferably 1/32 of an 
inch. The propeller with seven flights is also ferromagnetic and it causes 
at least about seven changes in direction of the water for each four 
inches of length or about 28 to 30 changes in direction per lineal foot. 
With this straight line flow there is combined a blowdown of the sludge in 
the boiler which departs from the conventional blowdown from the bottom of 
the boiler by introducing a separate straight line enlarged sludge 
collector constituting an external pipe with a diameter about three times 
the diameter of the opening at the bottom of the boiler. In numerical 
terms, this opening is generally about 1 inch in the standard 300 
horsepower boiler and the external sludge collector has a diameter of at 
least 21/2-4 inches, preferably 3 inches. The combination of the gravity 
flow within the boiler to the external sludge collector which follows the 
electromagnetic pretreatment in the 1/32 of an inch clearance between the 
propeller and tube achieves a precipitation of sludge in non-sticky form 
which collects continuously in the external sludge collector so that it 
can be removed by blowing. 
Applicant has experimented with these boiler installations over a period of 
seven years and has for the first time discovered that it is possible to 
remove the sludge completely from the interior of the boilers if there are 
no curved or serpentine passageways which do not clog up and if the normal 
circulation within the boiler is aided by simple gravity to remove the 
sludge from the boiler to the external sludge collector. Without 
electromagnetic treatment the sludge is sticky and coalesces in large 
particles which then crystallize, harden and adhere to the metal. If 
mechanical removal of the sludge by blowdown is carried out and if the 
blowdown is initiated as soon as the solids content rises above a 
pre-determined value, the sludge still is sticky, crystallizes, hardens 
and forms scale. Only the electromagnetic treatment of all of the water 
with its dissolved solids and suspended organic matter appears to assure 
that the sludge can be passed by gravity from the interior of the tank to 
the external sludge collector from which it is removed by blowing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1 there is shown the prior art of the inventor's electromagnetic 
water treatment which has been used for the past two to three years in 
which a 7 flight propeller constitutes the secondary rotating magnetic 
field in the electromagnetic water conditioning unit of the type shown in 
U.S. Pat. No. 4,151,090 and shown in Ser. No. 153,219, filed May 27, 1980, 
now U.S. Pat. No. 4,288,323, in which this unit is connected to treat all 
of the incoming water from reservoir 50 into the conventional boiler 10. 
In a conventional combination of electromagnetic free-flow water treatment 
apparatus and boiler 10 of this prior art represented by FIG. 1 the level 
of the water in the boiler shown at 20 is controlled by the automatic 
level controller 21, which provides free head space above the liquid 
interface. All of the incoming water passes through the electromagnetic 
treating unit 160 from the reservoir 50. U.S. Pat. No. 3,512,507 to Dixon 
shows the connection a bottom blowdown device of the prior art to the 
blowdown opening 13 within a boiler 10 fitted with automatic level control 
and connected to a valve for the purpose of removing water from the boiler 
when the maximum solids content of the boiler water goes above a 
pre-determined value. In combining the electromagnetic treatment to all of 
the feed water to the boiler as in Dixon U.S. Pat. No. 3,512,507, the 
inventor has discovered that sludge is resuspended within the boiler and 
the resuspension prevents the desired efficiency of sludge removal from 
being achieved. 
The main distinction between the prior art treatment of FIG. 1 which is 
based upon the inventor's own experience over the past two to three years, 
and the inventive embodiment of external sludge collector go connected to 
inlet 78 and outlet 79 as illustrated in FIG. 2 is directed to the problem 
of resuspension of the sludge within the boiler during blowdown 
operations. 
Applicant has also employed bottom blowdown as described in patent to 
Anderson U.S. Pat. No. 3,908,605 and in the patent to Holdt U.S. Pat. No. 
3,680,531, using end timed blowdown and as widely practised in the prior 
art. This has not been satisfactory. 
Top blowdown has been unsatisfactory. It is only the combination of 
electromagnetic treatment and external blowdown outside of the boiler 
which has proven to be useful in eliminating resuspension of sludge in the 
boiler. The essential structure in FIG. 2 which overcomes the difficulty 
of the prior art is the enlarged diameter of the external blowdown pipe 
consisting of a straight pipe of diameter 21/2 to 4 times the diameter of 
the connecting pipe from the boiler which uniquely permits the sludge to 
collect outside of the boiler under the negative angle of 
0.degree.-3.degree. and at the same temperature of the water inside of the 
boiler. It is believed that the combination of streamlined flow from the 
rotation of the propeller under the intense field of 1150 gauss in the 
pipe about 1" diameter contributes in a new way to the separation of the 
sludge created in the boiler because of the flow through the conventional 
blowdown opening of about 1" as shown at opening 13 in Dixon U.S. Pat. No. 
3,512,507 which corresponds to opening 78, in FIGS. 1 and 2. The return 
pipe 79 having the same 1" diameter and being at the far end of the 
enlarged straight pipe external sludge collector 90. The increase in 
diameter from 1" to at least 21/2", or preferably 3" and up to 4" increase 
the volume of hot water in the enlarged external blowdown collector 90. If 
one were to use a conventional 1" pipe 14, as shown in FIG. 1, one would 
not be able to control the sludge buildup in the straightened line pipe 
section and there would be no margin of safety, nor any opportunity to 
view the collection of sludge by direct or indirect means. Indeed, it is 
an important feature of the present invention that a turbidimeter is shown 
in FIG. 2 but installed in bottom blowdown sludge collector pipe 90 in the 
lower end thereof adjacent the outlet which permits the turbidity to be 
checked independently of the rate of total dissolved solids e.g. the TDS 
rating which is provided by probe 32 within the boiler below the level of 
the liquid 20. The blowdown value 94 is electrically connected to the 
probe so that it is responsive to the TDS value which is sensed by the 
probe 32 for independent assurance of proper operation of incoming water 
from feed reservoir 50, of level flow recognition by flow regulator 21 and 
of TDS control, all being independently verified through the readings from 
the turbidimeter 96. This opportunity is of great advantage where dirty 
water is used for the boiler feed. Under these circumstances where the 
water is not only dirty but may be of extremely high hardness value, it is 
contemplated that chemicals can be added, in particular synthetic 
chemicals based upon derivatives of acrylic acid which will precipitate 
calcium and magnesium salts and therefore condition the feed water with 
the result that the precipitate collected within the external sludge 
collector 90 can be blown out by the operation of the probe 32, as well as 
by manual operation. 
The operation of the prior art device as shown in FIG. 1 utilizes an 
automatic level controller which comprises a reservoir 50 for water from 
which the liquid passes through pipe 157 through pump 159 through the 
valving system in line 166 and then into the water intake for the 
automatic level system shown at water inlet 92. The operation of this 
automatic water feed has been a very assuring feature to prevent the 
boiler from going to dryness since the sight glass permits visual checking 
of the water level in reservoir 50 and the only requirement is that the 
reservoir 50 be maintained in liquid filled condition at all times. 
However, the collection of sediment, which occurs during the normal 
boiling operation, has constituted a major impediment to obtaining the 
major efficiency of the electromagnetic water treatment to all of the feed 
water in the boiler. 
It is remarkable to discover that enhanced operation is achieved in the 
presence of chemical agents, as well as in the absence of these agents by 
virtue of the combined mechanical safety of external bottom blowdown 
coupled with electromagnetic water treatment. In this connection, one must 
take into account the characteristics of the feed water to the boiler, 
especially with respect to the suspended insoluble particles which tend to 
clog valve openings for the automatic level 21 and to this end there is 
provided an extension pipe 24 from the level controller 21 into the large 
diameter conduit 90 so that there is no buildup of debris at the ball 
float 23 of the constant level 21. A sight glass 25 is part of the level 
controller 21 to verify the operativeness of the level controller 21 and 
the control unit 89 is wired to operate both the level controller ball 
float 23, as well as the extension pipe 24 at location W as shown in FIG. 
2. It is recommended where the water is dirty and holds suspended debris 
that the operation of the float valve be assured by draining the control 
into the sludge collector conduit 90 at least once a day and then 
refilling the controller to its desired level through the piping system 
through reservoir 50 through the electromagnetic unit 160 and into the 
inlet 92 into the boiler. 
The electrical connections for the electromagnetic coils of the prior art 
unit 160 are shown at junction 170 and a pump 159 draws water through 
inlet pipe 157 from the reservoir 50 through the valves into the inlet 164 
of the electromagnetic unit and out of the outlet 162 after treatment by 
the static field of about 1100 gauss and the secondary field within the 
electromagnetic treating unit. 
Each of the T-shaped fittings 130 are assembled with the bearing assemblies 
120 and these are axially secured by weldings 118 or other conventional 
suitable securing means, on opposite ends of the central conduit pipe 114. 
The T-shaped fittings 130, may be constructed of black iron pipe, 
galvanized iron, stainless steel or suitable plastic material, such as 
PVC, ABS, Delrin, ACETAL, or LEXAN. Each of the T-shaped fittings 130 
includes internally threaded port means 110 to introduce the untreated 
feed water. 
The T-shaped fitting 130 is formed with an internally threaded inlet 110 
the other T-shaped fitting at the outlet is formed with an internally 
threaded outlet. Each of the T-shaped fittings 130 is formed with a volute 
200 having its largest radius directed substantially radially and at a 
right angle with respect to the port openings 110, as viewed in FIG. 6. 
Feed water under pressure from the pump tends to fill the entire volume of 
the T-shaped fittings 130 and to flush out any air or other gases from all 
dead spaces which might otherwise be by-passed. 
The above details of the inlet, outlet and the propeller are precisely 
those which are set forth in my co-pending application Ser. No. 153,219, 
filed May 27, 1980, now U.S. Pat. No. 4,288,323. 
The relationship of the primary electromagnetic field to the secondary 
rotating electromagnetic field which is referred to hereinabove can best 
be clarified from FIG. 5 in which the relationship of the propeller to the 
diameter and length of the ferromagnetic pipe is illustrated. 
The propeller 150 is ferromagnetic as shown in FIG. 5 and is integral with 
the propeller shaft and provides the secondary magnetic treatment by the 
rotation of its six to eight flights of ferromagnetic material extending 
the full length of the electromagnetic coil 134, so as to produce a high 
flux density and field intensity surrounding the blades of propeller 150. 
The shaft 133 is provided adjacent the ends thereof with stainless steel 
washers 116. 
The six to eight flights 115 of the helical propeller provide an inner 
surface which resists flow in the direction of the arrow, e.g., city water 
and rotate at from 200 rpm to 800 rpm. The close spacing and rotation, 
even at lower water pressure, provide a sweeping action along the entire 
conduit pipe 114. The induced magnetic field effectively suspends 
particles which respond to the magnetic fields and to the rotational 
sweeping action. 
The end portions of the propeller shaft 133 are supported by bearing 
bushings 120 at each end thereof which are constructed of materials to 
provide long life, friction-free, with infinitesimal whip or whirl. 
The bearing bushings 120 are secured to externally threaded male pipe plugs 
100. This may be accomplished by a press fit, cement or other conventional 
securing means. Each of the male pipe plugs 100 is provided with central 
projections 121 to facilitate installation or removal from the T-shaped 
fittings 130. 
The adjustment and scale of the primary and secondary electromagnetic field 
can be better understood from the inventor's experience with different 
sizes of boilers. The conventional boiler as shown in FIGS. 1 and 2 is 
fitted with 1 inch of pipe at bottom outlets 78 and 79 and the same 1 inch 
diameter pipe is used in a 4 inch length for the smaller size commercial 
boiler. This 4 inch length may be increased by 20% as the diameter is 
scaled up to 4 inches for the very large boiler installations. The primary 
dc current of 24 volts which energizes the coil 134 of the permanent 
stationary electromagnetic field provides a current intensity of about 5 
amperes on the average in the 1 inch diameter pipe size. As the diameter 
increases to 4 inches, the amperage can vary up to 18 amperes. This 
results in a stationary magnetic field of 1150 gauss. 
The winding of the coil may be copper or aluminum, aluminum contributing to 
a lower weight for the unit. The wire may vary from No. 15 wire at 165 
mils down to No. 6 wire at 345 mils. 
The inventor has tested the installation of FIG. 1 designated as prior art 
to determine whether adjusting the current, the primary magnetic field and 
the secondary magnetic field can in any combination or variation improve 
the characteristics of the sludge which forms to facilitate its blowdown 
from the interior of the boiler using standard bottom blowdown equipment 
or top blowdown equipment. In this on-going study which the inventor has 
made during the past few years, the constant electromagnetic field of the 
coil was reduced by 25% and 50%, e.g., from 1150 to 600 and then to 750 
gauss. The result was that the treatment was insufficient. Insufficient 
treatment resulted in poor separation. It was determined that a minimum of 
900 gauss for the primary field was required. The flights of the propeller 
were changed from 2 to 8 and then to 16. Between 8 and 16 the additional 
flights were ineffective to add any improvement. Between 2 and 8 
remarkable improvement was achieved which manifested itself in maintaining 
the propeller unit from all organic deposits for a period of about two 
years when 8 flights were used and only 6 weeks when two flights were 
used. The use of these 8 flights in a 4 inch length of pipe is intimately 
connected with the clearance of the propeller from the inside wall of the 
pipe, the clearance being critical between 1/16 of an inch and 1/64 of an 
inch. At a clearance of 1/8 of an inch the treatment is totally 
ineffective to condition the separated sludge in a form for easy removal. 
If the clearance is closer than 1/64 of an inch mechanical problems occur 
and the propeller wears away at its edge or on the inner wall of the pipe. 
It is clear that between 6 and 8 flights there is a change in direction 
within the pipe of 4 to 6 inch length which can vary from about 24 changes 
per lineal foot to 32 changes per lineal foot, preferably 28 changes per 
lineal foot. These changes are controlled along a helical path. These 
changes can be repeated by the axial vector which lies normal to the 
direction of flow. The secondary field which is generated by the movement 
of the propeller at between 200 rpm and 800 rpm provides a significant 
contributing effect which is believed to distinguish between all other 
electromagnetic field treatments. 
For example, the patent to Almasi U.S. Pat. No. 3,714,037, utilizes a 
magnetic field of 900-1200 gauss at the center of a restricted passage 
which is very wide in relation to its height but there is no propeller 
movement to generate a secondary field and there is a special piping 
provision to separate particles which are magnetized and agglomerated. 
There are no other magnetic fields comparable to that which is used by 
applicant. 
The present inventor is well aware of every use which has been made of the 
electromagnetic unit of this invention with a boiler and has kept a record 
of every sale, installation and the performance. This is the first 
instance described in this application in which this electromagnetic unit 
has been used in conjunction with a bottom boiler blowdown device outside 
of the boiler and in which the equipment comprises a sensing probe which 
will determine the total dissolved solids limit above which the electrical 
signal will actuate a solenoid valve to blow out a predetermined amount of 
liquid in a predetermined time from a straight horizontal pipe outside of 
the boiler while the liquid content is replenished. The device of the 
invention for accomplishing this bottom blowdown outside of the boiler is 
illustrated in FIG. 2. 
The problem encountered in the prior art combination of FIG. 1 is that 
bottom blowdown in the boiler itself is not effective because of the lack 
of assurance that the boiler engineer will not permit the boiler to be 
heated to dryness. Top blowdown does not succeed because sludge collects 
at the bottom in any event. Combined top and bottom blowdown is wasteful 
and requires more effort than can be saved. It is only the device of the 
invention which carries out bottom blowdown outside of the boiler which 
solves the problem facing the prior art. 
In FIG. 2 the sensing probe 32 is immersed a predetermined distance below 
the level 20 of the water in the boiler 10 and senses the total solids 
content at a location remote from the feed water inlet at location 92 
adjacent the electromagnetic treatment end of the boiler 10. All of the 
feed water must pass through the electromagnetic treating unit which is 
shown in detail in FIG. 5 and comprises the single package 131 with the 
propeller 150 having the 6-8 flights of ferromagnetic material. 
The conductivity probe 30 as shown in FIG. 2 is electrically connected to 
the control unit 89 which is a single control unit for the automatic 
blowdown of the sludge out of the external sludge collector 90 by means of 
the solenoid valve 94. The probe may be bought from Minneapolis Honeywell 
or Beckman Instrument Co. A preferred model is Beckman Model RAS7 Solu 
Meter Solution Conductivity. 
The unitary package 131 is connected to the usual 110 volt ac line 135 
(FIG. 5) step down transformer 136, a full wave rectifier 137 and dc leads 
to pilot light 138. The step down transformer 136 reduces the voltage to 
24 volts and then connects to the electromagnetic coil 134. 
An electrical tap 302 is provided to supply dc current to the sensing probe 
which is used for the TDS monitoring operation and is shown in FIG. 4. It 
is a feature of the invention that the same dc voltage feeds the sensing 
probe to detect total dissolved solids and is used to energize the 
permanent dc electromagnetic winding. The dc voltage is 24 volts and is 
shown in the circuit of FIG. 4 which is part of the control panel. 
The schematic for the construction of the control panel 300 is shown in 
FIG. 4. The control panel comprises a step down transformer 136 from 110 
volts to 24 volts and a full wave rectifier 137 of ac to dc to energize 
both the permanent magnet dc winding 134 of the electromagnetic core 
wrapping about the ferromagnetic tube 114 of the electromagnetic treating 
unit. 
In the operation of the control panel 300 as shown in FIG. 4, the fuse 
marked with a legend in the primary of the step-down transformer 136 
serves to guard against that unacceptable surges in line voltage so that 
for the continuous operation of the transformer 136 only the fuse need be 
checked. The ammeter in the line to the electromagnetic unit 160 is useful 
to gauge the field and to assure that the desired value of 1150 gauss is 
achieved. The tap from the full wave rectifier 137 to the TDS monitoring 
system assures that the probe 32 is energized and the block diagram of 
FIG. 3 is useful to monitor the operation of blowdown. 
A very high abnormal reading of TDS, which is given by the probe 32, serves 
to light up the lamp indicator with the legend "HIGH" whereby, as shown by 
the arrow the blowdown valve 94 is closed, fresh feed water comes in and 
blowdown is effected whereby the TDS recedes. 
A 20 second delay to permit these operations to occur is provided and if 
there is any fault or failure of the intended operation, the alarm for 
high abnormal is set off. 
If the value of TDS sensed by the probe 32 is merely high normal, the alarm 
system is by-passed and the blowdown valve 94 is closed directly, while 
the feed water comes in and the TDS value recedes. 
Where the setting of the probe 32 at the low end indicates a very low 
normal which could involve an overdose of chemical treatment and thereby 
the possibility of harming the operation by the introduction of unwanted 
chemical, the very low reading sounds the alarm as shown in the block 
diagram in FIG. 3. The low value could also be an indication that the 
probe 32 is not operating and hence a zero reading is given. In this case 
the alarm sounds. If this inoperative condition is caught on the way to 
zero, the "low" lamp indicator lights up, the blowdown valve is closed and 
blowdown occurs so that there will be no possibility of the boiler running 
dry due to the non-functioning of the probe. 
In this warning system which is illustrated in FIG. 3 the time of blowdown 
is controlled by a commercial timer in known manner. The blowdown cycle 
may be 10 seconds every 2 hours, every 3 hours or every 4 hours depending 
upon the solids content of the feed water, the steam output of the boiler 
and the organic matter present in the feed water. 
The safety and energy savings which are provided by the combination of 
electromagnetic water treatment of all of the boiler feed water with 
external blowdown in the enlarged external sludge connector below the 
boiler, enlarged from the standard L fitting in the boiler to a diameter 
21/2-4 times that of the standard L fitting is the result of a new 
cooperation between the electromagnetic water treatment and the blowdown 
from the straight line section of the external sludge collector. 
The energy savings resulting from the blowdown in the separate sludge 
collector conduit can be better understood in view of the negative slope 
of 0.degree. to 3.degree. of the external sludge collector. For a 6 foot 
long section, the center line at the inlet 78 to the conduit 90 is 1/2 
inch to 1 inch above the center line at the outlet 79 so that the sludge 
advances towards the outlet 79 under the force of gravity while permitting 
free circulation because of the enlargement of the diameter from the 1 
inch at the bottom of the boiler the L shaped inlet to the 3 inches of 
diameter shown in the preferred embodiment. 
Since the start of the water treatment in the first step is based on the 
water flow through a 1 inch diameter pipe 4 inches long in the 
electromagnetic treatment unit, it is seen that the 1 inch inflow an inlet 
92 in the boiler is followed by a sludge path depending from a 1 inch pipe 
78, without impediment into sludge collector 90 with its 3 inch diameter. 
The larger water mass in the sludge collector retains the heat to a 
temperature value much closer to that in the boiler while the solids move 
slightly by gravity towards the turbidimeter location 96 and the blowdown 
valve 94. 
There is no impediment to sludge collection by gravity in conduit 90. 
There is no impediment to collection at the lower end of conduit 90 and 
still there is no likelihood of plugging the valve because of the very 
slight drop. On the other hand, if the conduit slanted upwardly, there 
could be a plugging of the conduit 90 which takes place. 
The short distance between the electromagnetic unit 160, inlet 92 and the 
entrance to conduit 90 assures that the magnetization which occurs if the 
liquid feed water conditions the precipitate so that it will not stick and 
be quickly removed by the blowdown valve 94. The rapid change in direction 
by the propeller flights (24 to 32 per lineal foot) in the electromagnetic 
unit and the 1/16" to 1/64" clearance for the water assures a high rate of 
flow, unimpeded by any turns, at a velocity of the propeller of 200-800 
rpm. 
The negative slope which aids the gentle gravity forces can be achieved if 
the boiler 10 is level and the connecting fitting to 79 is longer than the 
connecting fitting to 78. However, the tilted boiler is preferred. 
The turbidimeter used is available from Hack Chemical Company and is 
described at page 129 of the Handbook of Advanced Wastewater Treatment by 
Culp, et al., published by Van Nostrand Reinhold Company, 1978. 
It noteworthy to contrast the path of the water from Reservoir 50 in the 
prior art of FIG. 1 with the invention of FIG. 2, through the 
electromagnetic unit, into the boiler heated at the near end. The 
electromagnetic unit 160 as shown in FIG. 1 exhibits the same path as the 
water path in the preferred embodiment of FIG. 2. Also FIG. 2 utilized the 
same conventional reservoir 50 but adds the conductometric probe 32 at the 
far end of the heated boiler in electrical connection with the control 
unit 300 and also adds the external sludge collector 90, which removes 
sludge as soon as it is formed in the boiler. Finally a blowdown valve is 
attached to the exit of the external sludge collector. These added 
features cooperate in a new way to provide a result which cannot be 
achieved in the prior art. 
In the prior art of FIG. 1, organic matter, suspended debris, and oily 
material tends to collect in the boiler as a result of evaporation of the 
heat. In the invention in FIG. 2 all of these materials are removed under 
natural circulation forces to the enlarged conduit 90, through the 
openings at the bottom of the boiler. It appears that the enlarged 
diameter of conduit 90 enhances this circulation which is not present in 
the narrow external horizontal pipe below the bottom of the boiler in FIG. 
1. It appears further the large, hot liquid mass in conduit 90 in 
communication through the short connection promotes this circulation.