Note: Descriptions are shown in the official language in which they were submitted.
~53~79 ~
~he present invention relate~ to apparatus for
~he resolution of an emulsion consisting of immiscible ~ ~
external and internal liquid phases. More particularly, ,~i"
the invention relates to the electric treatment of oil-
continuous amulsions containing dispersed aqueous phase
,-' contaminating substances.
` Electric treaters have been employed for many
years for resolving emulsion5 formed of immiqcible external ~
and internal liquid phases. Usually the external phase is ~,
oil-continuous, and the internal phase is a dispersed aqueous ~;
contaminaking substance. The term "oil" includes ~arious
typ,es of materials such as petxoleum and i~s product~, and
~ va~ious types of organic liquids. The internal phase is'
; aqueous and usually~will be a caustlc or acid solution. One
o~,the'most common emuls~ons whiah is resolved in electric
,i treaters i8 water;in-crude oil. Fox purposes of removing
, sal~, the crude oil is mixed with a quantity of dispersed
fræsh water. A high voltage electrical field resolves the
emuleion by coalescing the inte~rnal phase into a bulk phase
(carrying removed salt) which separates by gravity from the -'
continuous external crude oil phase. The terms resolution
and coaLescence are used in their general meanings to denote
t~e agglomeration,o~ the dispersed internal phase in the
continuous external phase. ~ -
~ Conventional electric treaters have employed
high voltage rom external power sources of 11 to about 33
ki}ovolts applied to electrodes that create the ,elec~rical
fiel'd. However, energizing potentials of othex value~ have
'I ` been used in certain applications. The spacing between the
electr~des defining the electric field produces voltage
:
~' 2 ~ ,
;
:., ~ - .:.. ~
~l~953~
gradients in the range o~ about 2.5 kilovolts to about 8.5
kilovolts per inch of spacing.
Electric treaters employed for resolving emulsions
have relatively simllar con structions, The treater gener-
ally e~ploys a pressure-type metal ves~el which contains an
inlet for introduci~g the emulsion and outlets to xemove the
; continuous phase and the coalesced internal phase. In addi-
tion, the vessel contains electrodes for creating the elec-
trical field. One ox more energized electrodes can be sus-
pended within the vessel but are electrically isolated from
; its metal sidewalls~ The electrical curren~, from an ex-
ternal power source~ is carr:ied to the energized electrodes
th~ough the metal sidewall oE the vessel by an electrical
insulating device which is termed an "entrance bushing".
~he entrance bushing has metal parts to integrally connect
; with the sidewall of the vessel; and also it has insulating ~-~
components to pass the electrical current in electrical
isolation through the metal sidewall of the vessel to the
ener~ized e}ectrode. ~he entra~ce hushing must pxovide the
nesessar~ electrical ;inte~rconnection and a liquid-tight seal
.
at t,he metaL sidewall of the vessel under the temperature-
pressure environment in which the emulsion is resolved within
the- vessel.
Prior co~structions of the entrance bushing have
25 ~ wi~hstood moderate temperatures~ and pressureæ of the emulsion
. .
;~ wi~hin the vessel while conducting h.igh potential current to
th~ energized electrode. Present state of the art teahniques ! '
rsquire that the insulating cdmponents o~ the ehtrance bu h~
i~g are formed of polymer-type insulating plastic materials
such a~ ~eflon . Entrance bushings with these plastic
~ .
~, .
: . . : . - :
~S3~7~ :~
materials provide exceptional qervice in commercial appli-
cations on electric t~eaters for resolving emulsions. These
bushings are exceptional in design in that they operate
under exceptional envixonments where subjected simultaneously
; 5 to temperatures as high as 400F. and fluid pressures up to
150 psi during normal operation o~ the electric treater;
Present day operation of electric tr0aters, o
the nature employed in reiineries, is placing a heavy burder
:
upon even these entrance bushings~ The temperature and
pressure of the emulsion being resolved in electric treaters
have steadily increased in the recent decade. Operating
conditl~ns ase being approached which the plastic insulating
.: .
materials of the entrance bushing cannot withstand in terms
of operational life~and maintenance of high safety character-
istics. In one particular oil refinery, the heatlng, elec~
t~ical field desalting and distillation process steps are ~i~
; arranged to canserve head energy. For this purpose, the
cr~lde oil is heated to substantial temperatures (e.g. 375F~
upstream o~ the electric treatex by heat exchange with the
products of distillation and other petroleum thermal treating
pro~edures. In some instances/ the oil refinery could be
even more e~icicntly operated i~the crude oil before pass-
inc3 through the el~ctrical treater for desalting or dehydra-
tion,purposes;could be heated to temperatures approaching
~00~.~ These severe~temperatures require very high pre~-
sures of 500 psi or more to maintain the crude oil within a
uid phase ondition in the electric treat~r. The plastic ;
inæulating material,~especialiy Teflon, has excellent mechani- ~ ;
cal~and electriaal;properties. However, the design of an
30~ entr~nce bushing to withstana these exceptionally elevatea
4 ~
. '
-
~Lo~
temperatur~s and high pressure~ becomes a serious task sothat the present outstanding operational life and safety
characteristics of entrance bushings can be maintained. :~
Entrance bushings constructed with proper plastic ~:
insulating material can withstand very high operating pres~
sure in the range of several thousand psi where the tempera- :~
tures are relatively low, for example, ambient temperature
of 60-80 degrees F. Al~enlatively, thase bushings can ~:~
withstand relatively high temperatures of up to about 500F.
where the operating pressure is relatively low, for example,
` 15 psi differential across the plastic insulating material. .
-~ In ~ither case, the plastlc .insulating material can be used
: wi.~hin an ~tran~e bushing a:nd safely isolate electrical
potentials up~t~ 50 kilovolts ~ac-dcl for extended periods ..
1~ of time and in complete sa~e~y.
~e~i~ning antrance bush~n~s incorp~rat~ng plastic ~ ~:
insulating material i~ very di~ficu~ wh~n such a device
. ~
mu ~ withSt D d;simultaneously elevated operating pressures
(500~ps~ and temperatures (500F). Teflon is ~ypical of
: 20 a number of:high electrical resistance plastic materials ^ ~?
which are 9ubject to plastic flow upon increase in tempera-
ture and pressure. At elevated temperatures, these insulat- :
i~g materials are subject to plas~ic ~low when subjec~ed . ~;
simultaneously to hlgh operating pressures, : ~-
: 25 In ~he~conventional entrance bushing, the plastic
insulating materlal projeo~s as a tubular member into the ~
veq~ei containing the emulsion. Lower and upper fLuid seals ~.
preven~ the eacape of emulsion rom ~he vessel through the
internal parts of the entrance bushing. For example, ~he
upper por~ion o~ the tubular member of th~ plastic i8 carried
' ~
.
" :~
~S3~
in a metal adapter which is mounted in the sidewall of the
vessel. The insulatin~l material has a thermal expansion
coefficient several times that of the metal ~steel) compon-
ents o the Pntrance bushiny. Also, this insulating material
; 5 in the cycling of operat:ing temperatures, ratains the struc-ture induced at the maximum temperature. A substantial
temperature gradient established alon~ the tubular member
; and across metal parts which form fluid seals creates severe
longitudinal stresses to produce seal failure. Emulsion
leakage into the entrance bushing results with entry into
the metal conduit which contains the electrical conductor
con~necting to the external power source. An electrical arc
ma~ then occur which can deskroy the electrical conductor,
the entrance bushing, or both. Although electrical treaters
carry devices to aisconnect the electrical current ~rom the
ene~rgized electrode upon such an arc, substantial repairs
.
are usually necessaxy to place the electric treater into
operation. Thus, as the emulsion within the electric treater
increases simultaneously in both pressure and temperature,
designing an adequate entrance bushing which can be operated
continuously in a high degree of safety becomes a dif~icult
challenge.
Systems to remove the bushing from such environ-
ment have been utilized. Ideally, such a system with the
electrical treater functions so that the entrance bushing
within the vessel can operate without suffering both high
te~peratures and high pressures. The present invention pro-
vides such an impxoved electrical system.
In accordance with the present invention there is
prov ded an el~ctrical treater system adapted for resolving
~53~
emulsions in a high te}nperature, high pressure environment.
The electric treater sYrstem includes a vessel for containing
the emulsion while subje~cted to an electric field created
by electrode means, including an energized electrode mounted
in electrical isolation ~rom the vessel. A high voltage
bushing mounted wi~lin t:he. sidewall of the vessel has an
elongated tubular member projecting into the vessel and ~`
immersed within the emulsion. This tubular member, of a
high electrical resistance, plastic insulating material, is
subject to plastic flow upon increase in temperature and
pressure. A conductor extends through the tubular member
and connects at its vessel interior end to the energized
el~ctrode. The tubular member at its other end is carried
in a.metal adapter mounted in the sidewall of the vessel.
The metal adapter includes a heat sink means or maintaining
t~e length of the tubular member at substantially the same
temperature as the emulsion. An aperture in the metal adapter
passes the conductor to the exterior of the vessel. A pres~
sure conduit extends in fluid-tight relationship from the
metal adapter to an external power source having a high
vol~age output. A hihg pressure, high voltage feed-through ~ -
insulator means seals the pressure conduit at the external
poler source. An interconnecting high voltage conductor
within a dielectric liquid is carried in electrical isola-
tion within the pressure conduit and connects between the
condu~tor in the entrance bushing and the high voltage out~
pu~ of the external power source through the feed-through
insulator means. A system mean<; maintains the dielectric
~ uid at su~stantially the same pressure as the emulsion -
with~n the vessel. This systeïn means in~ludes a dynamic
7 -
'. ...
~.
~053~7~ ~:
:~luid barrier f`or prevent:Lng intermingling of the emulsion
and dielectric liquid. Heat exchanger means on the pressure
conduit maintain the high pressure, high voltage feed-through
insulator means at substantially the same temperature at its
pressure condult and power source term1nals.
The obJects and features of the present invention
will be best understood from the following description of
: the accompanying drawings, in which~
Figure 1 is a view in elevation, partially in
cross-section, of an electric treating system of the present
invention;
. Figure 2 is a vertical section of one emhodiment ~ :
'~ of an entrance bushing carried in an electric treater;
Figure 3 is a longitudinal section of a dynamic :
fluid barrier associated with the system shown in Figure l;
Figure 4 is a longitudinal section through one
embodiment of a feed-through insulator employed in the system
. :
shown in Figure l; `~
Figure 5 is a longitudinal section through another
~1 20 embodiment of a feed-through insulator employed with the ~;
.~ system shown in Figure l;
Figure 6 is a view in elevation, partially in
I cross section, of a second embodiment of the electric treater
! i.
system of the present invention; ;~
Figure 7 is a longitudinal section of another ~:
::,. ~ ::
embodiment of the feed-through insulator with a fluid-
actuated seal for use in the system shown in Figure 6; and
.' , : ;: . ~
i! Figure 8 is a longitudinal section through a
` fluid amplifier employed with the system shown in Figure 6
, 30 for actuating the feed-through insulator shown in Figure 7. ::
~ .
,~ - 8 -
.:
::
r ~
~(3~3~79 ~:
Refexring now to Figure 1 of the drawings, there
is shown a system of ~he present invention for electrically
tr~ating an emulsion for its resolution through application
o~ electrical field forces. The electric treating system
S includes a vessel 12 which contains the emulsion at suitable
temperature and pr~ssure during resolution. The vessel 12
has metal sidewalls which enclose Plectrode~ 13 and 14 and
carry in~ulation lS~ These electrodes may take any suitable
configuration but p~eferably they are planar, spaced apart
~oraminous metal grids. In the present description, the
electrode 13 is grounded to the vessel 12 and the energized
electrode 14 is carried in e}ectrical isolatiQn relative to
the metal portions of the vesse} 12. The enexgized electrode
14 can be suspended from the vessel 12 upon insulator~
(which are not shown in the present drawings). The vessel ~ -~
12 can be of conventional design with inlet and outlet `
. . .
conduits for bringing emulsion into the ve sel 12 and for
removing the coaleqced~internal phase and the treatea ex
,
ternal phase.
; : .
The energized electrode I4 receives high potential
cur~ent from an external ~ower source 16. The power sourca
16 can be a DC power pack which produae~ elevated DC poten-
tials, e.g. 33 kv dc. Alternatively the power source 16
can be a transformer energized from available AC supply ,
sources with an output of convenient magnitude, e.g. 13 kv ac.
The high potential current ~rom the power source 16 iq car-
ried through 3. metal pressure conduit 17 to an entrance
bushing 18 which then passes the curren~, in electrica~ iso~
~ ,. .
` ~ lation relative to the vessel 12, through a flexible lead
19 t~ tha energlzed electrode 14. The electrode 14 energized
.
g ~ ~
~Q53~L7~ ~:
to elevated potentials creates ~n electric field wlthin the
vessel 12 for resolving the emul~ion.
The entrance hushing 18, as seen in greater de-
tail in Fiyure 2, has a metal adapter 21 integr~lly secured
within the sidewall of ve~sel 12. For this purpose, the
adapter 21 may have a lower extremity 22 received within
complementary threads in an opening through the side-
wall of the vessel 12~ An elongated tubular member 23 pro-
ject3 from the metal adapter 21 into the interior o the
ves~el 12~ The tubular membex 23 is formed of a high elec- ;
trical resistance, plastic insulating material, preferably,
a polymeric solid not readily wetted by the emulsion or
accumulating deposits of arc inducing materials. It is
preferable to use polytetrafluoroethylene ("Teflon"), or
` 15 in lesser severe environmental conditions to employ polytri-
fluorochloroethylene ~Kel-F")~ However, other equivalent
plastic insulating materials mcLy be employed, if desired.
Preferably, the tubular member 23 has a uniform
cylindrical ex'cerior surface 24 whiah is relatively free of
scratches or ridge3 that promote the accumulations of arc
ind~laing materials. The tubular member 23 has a longitudinal
passage 26 extending between its top and bottom extremities.
Th~ pas~age 26 ac~ommodate~ a high voltage cable 27 with an
electrica~ conductor 28 enca~ed within a plastio sheath.
This pla~t~c sheath is of a plastic material ~imilar to the
tubular member 23. However, the cable 27 may be formed of
other materials capable of resisting dielectric puncture at
the high voltages which are applied to khe electrode 14 of
~he ves~el~l2~ The lower~extremlty of the tubular member
:
23 is pro~ided with a first threaded portion 29 in which is
53~7~
received a metal sleeve 31. The metal sleeve 31 has a
complementary passageway for the conductor 28 which is
secuxed electrically to the sleeve 31 by silver solder 32.
The soldex 32 also provides a fluld-tlght seal at the bottom
of the sleeve 31.
The slee~e 31 is mounted within ths threaded
portion 29 in a fluid-tight conneation to withstand moder-
ate pressure di~ferentials. A relatively durable seal to
even elevated pressure diferentials is provid~d by first
wrapping the sleeve 31 with a very thin Teflon tape. The
sleeve 31 is cooled and the tubular member is heated, and
then, these parts are threaded together. Lastl~ , dielectric
heating fuses the tape between the threaded portion 29 and
the sleeve 31 to form an excellent high pressure fluid seal.
The lower portion of the tubular member 23 is completely
immersed in emulsion and is main~ained throughout its extent
a~jacent the sleeve 31 at a substantially uniform tempera-
tu~e (no significant thermal gxadient). ~hus, no thermal
~ stre~s created by differential lon~itudinal expansion exists ~`
along the threaded interconnection between the sleeve 31
and the tubular member 23.
The lead 19 could be secured directly to the end
of the slee~e 31. However, it is preferred to protect the
sleeYe 31 with an enclosing sleeve 34 mounted in a second
threaded portion 33 provided in the tubular member 23. The
sl~eYe 34 and threaded portion 33 interconneotion need not
pr~vide a~f1uid seal. The lower end of the leeve 34 is ~ ` -
closed by a cylindrical insert 36 secured in place, as by ~`
wQlding. The insert 36 has a projecting lug 37 carrying a
bolt and washer assembly 38 for connection to the lead 19
;
11
-
~I~S3~7~
In the conventional bushing, the end of the tubu- -
lar member 23 at the vessel 12 is cooled by the external
conduits connected thereto. As a result, the upper end of
the tubular membar 23 is under longitudinal ~hermal gradient
S which can disrupt fluid pressure seals. In the present
system, the adapter 21 is arranged with a heat sink 90 that
the entire upper portion of the tubular member ~3 is main-
ta med at substantially the same temperature as the emulsion
contained in the vessel 12. Fox this purpose, the upper
portion 41 of the tubular member 23 carries externaL threads
which inter-fit with internal threads 42 carried within the
interior o~ threaded portion 22 of the metal adapter 21. An
en~arged cylindriaal threaded portion 43 about the passageway
26 receives a metal sleeve 44 which extends beyond the
15 adapter 21 into the upper portion of the tubular member ~3.
Tha sleeve 44 is integrally connected to the metal adapter
21 by suitable means which provide for an efficient trans~er
of heat, and preferably, a fluid-tight metal~to-metal con-
- nection. For example, these components can be secured inte-
grally into metal-to-metal contact by an induction weld 46.
.
With this arrangement, the sidewall of the insulated vessel
1~ is at substantially the same temperature as the emulsion
in the ~essel 12. Heat energy can flow through the heat
sink pro~ided by metal-to-metal integral connection of ~he ~ -
adapter 21 and sleeve 44 about the upper end of the tubular
member 23. As a result, the tubular member 23 is without
significant longitudinally directed temperature gradients.
The insulation 15 preferably is carried about the entrance
bu~hing 18 up to and covering the metal adapter 21.
The slee~e 44 i9 mounted within the tubular
. .
12
~ ~)53~7~
me~ber 23 tc~ provide a pressure seal If desired, the sleeve ~-
44 is secured to the tubular member 23 in the same manner
as the sleeve 31 in a Eluid-tight interconnection through
the use of a plastic tape which is fusea to form the desired
S pressure seal. The induction weld 46 may generate a suffi-
cient temperature at the top end of the tubular member 23 to ;
generate a small amount of gas. This gas is vented to the
exterior o~ the metal adapter 21 by a vent port 47. The
vent port 47 is closed upon completion of the fabrication
by a small welded plug 48.
~ he pressure conduit 17 is connected in fluid-
tigh~ness to the metal adapter 21. For this purpose, a
coupling 49 rec ived wit~in a groove Sl in the metal adapter
21 is secured integrally to the metal adapter 21 by an in- ~ ~
lS duction weld 52. Although the coupling 49 removes heat energy ~ ;
from the metal adapter 21, the heat sink therein conducts
replacement heat energy ~rom the sidewall of th~ vèssel 12.
As a result, the tubular member 23 is maintained at sub-
stantially the~same temperature cluring operation of the ves-
,
~ sel~as the emulsion contalned therein irrespective of losses
through the coupling 49.
; Othex arrangements of the metal adapter 21 in the
entrance bushing 18 may be employed to provide a heat con-
.
~ducti-ve elemen integrally interposed between the tubular
25~ ~e.~ber~23 and~the pressure condult ~17. Preferably, the open-
ing in the metal adapter 21 accommodating the cable 27 is
; th~ sole aperture~through the heat conductive element. This~
arrangement insures that the tubular member 23 wlll be
m~intained at subs~antially the sama temperature throughout
its length, and at the te~perature of the emulsion within the
.
~ 13
:....................................................................... ~
~053~7~
vessel 12.
Returning now to Fig. 1, other ~eatures o~ the
pre~ent electxic treater system will be described. The
entrance bushing 18 usually resides within a noz~le 56 car-
5 ried upon the vessel 12. In particular, the nozzle 56 car~
`; ries a flange 54. The metal adapter 21 threadLy mounts into
a complementary flange cover 5'7 secured to the flange 54.
However, the entrance bushlng 18 may be placed directly in a .
coupling within the sidewall of the vessel 12. The coupling
49 connects the entrance bushing 18 to the pressure conduit
17. In this emhodiment, the pressure conduit 17 contains a
te~ 58 which permits fluid access to the dielectxic liquid ~.
surrounding the cable 27 wit:hin the pressure conduit 17.
: A system is provided ~or maintaining the dielectri~ .
li~uid within the high pr~ssure conduit 17 at substantially
.
the same pressure as the emulsion within the vessel 12. In
~.
thi~ system, a dynamic fluid barr:ier 59 is in fluid communi-
cation~wlth the emu].sion i:n the v~_.ssel 12 and the dielectrio
: : liquid within the pressure conduit 17. ~or this purpose,
20;~: the:barrier:59 has an inlet conduit 61 connected to the
. .
noz~el 56 for sensing the emulsion's pressure within the
~vessel 12~ ~An outlet conduit 62 from the barrier 59 connects
- by a tee 63 and conduit 64 to the pressure conduit 17 ~or
applying fluid pressure to the dielectric liquid. Prefer-
ab7.y,~ the tee 63 connects to a valYe 66 to permik filling
: o~ the barrier 59 and pressure conduit 17 wlth dielectric
li~uid. ~he pressure condult 17 may also contain a tee 67 ; ~:~
: ~ adjacent the power source 16.: The tee 67 may carry a ~al~e :
.,
6~for venting~g~ases Erom the pressure conduit 17 to insure
~o a aon~letely Liquld-~lLled system.
~: 14
'
:- . - - . :...................... . . -
.. .. . .
~ 0~3~L~9 ~
The barrier S9 can have a vari2ty ~f elements
as long as these elements pravent the intermingling of the
emulsion and dielectri~ liquids while transmitting the
emulsion's pressure in the vessel 12 to the dielectric liquid
S within the pressure conduit 17. Preferably, the barxier 59
include~ an imperrneable fluia barrier displaceable by pres-
sure differential for isolating the emulsion and the dielec-
tric liquid while transmitti:ng fluid pressure from the emul~
sion to the dielectric liquid. With this system, the dielec~
tric liquid within the pressure conduit 17 is maintained at .
substantially the emuLsion's pressure within the vessel 12.
The impermeable flu.id barrie:r may be provided by various . ~
elements such as free piston.s, immiscible liquid barriers or : .; .
by 1.exible bellows.
. 15 In the preferred embodiment shown in Figure 3, .
: the barrier 59 has a flexible bellows 73. The barrier 59 .~
h~s a two piece tubular body formed of an inner-part 71 .;
recei~ed within an outer p.art 72 w.ith the free end of the
bellows 73 held in fluid-tightness by seals 74 and 76 con~
: :20 :fined between the body part~. The bellows 73 forms an inlet
chamber 77 and an outlet chamber 78 within the outer body
pa~t~. The inlet~chamber 77 is in ~luid communication to the
ve~sel 12 through the conduit 61. l'he outlet chamber 78 is `
in fluid communication with the pressure conduit 17 through
:25 ~ the.coDduit 62. ~ dielectric liquid, ~uch as transformer
`. oil or silicone grease, is introduced via the va~lve 66 to ~ ~`
fill the outlet chamber 78 and the pressure conduit 17 con~
taining the~cable~ 27.~ Any gas is vented through the valve
; 6~ until a liquid-fill condi~ion~wi~thin the pressure conduit
30 : 17 is obtained. At this time the valves 66 and 68 are closed.
- : i
: ~
`
7~
During operation of the vessel 12, the emulsion
(in a dehydra~ed formt passes upwardly of the electrodes to
~ill the conduit 61 and inlet chamber 77. Tha bellows 73
is then di~placed by differential pressure until the dielec-
tric liquid within the pressure conduit 17 is at the same
pres~ure as the emulsion within the ve~ssel 12. The passage- ;
way 26 in the tubular member 23 caxrying ca~le 27 also will
be filled with dielectric liquid at the same pre~sure as
the emulsion within the vessel 12. As a result! the used
seals between the sleeves 31 and 44, and the ~ubular member
23 are not subjected to any signif icant pressure differential.
Additionally, these fused seals between metal and plastic
ma~erial are maintained at the same temperature throughout
the tu~ular member 23. Thereforer no fused seal suffers
st~e9sed conditions caused by differential longikudinal
t~ermal expansion. As a significant result, the bushing 18
con~ains a plastic material which does not have to withstand
anv pressure forces across liquid-tight seals. The pIastic
mate~ial of tubular member 23 meIely has to provide the
necessary insulator for bringing high potential current
,
` ~hrcugh the conductor 28 to the electrode 14 in an in~ul~ted
, .
relationship to the sidewall o~ the vessel l~ at the emul- `~
n's temperature.
~ In the event of unforeseen accidents, explosions,
f~i~es, etc~, the pressure conduit 17 might have excessively
hi~h ~luid pressures developed in the dielectric }iquid.
Al~ernatively, the emulsion's pressure within the vessel 12
mig~t~increase~ above the designed Limits of the barrier 59.
~In either event, the barxier 59 can be arranged to prevent
3~ rup~uring of the bellows 73 by application of excessive
~:
16
~ 3~79
pressure differentials above certain magnitudes. For this
purpose, the barrier 59 is provided with a check-valve
arrangement. A valve member 81 is carried by the bellows
73 within the inlet chamber 77 ana has a projecting pin 82 ~`
which passes into the conduit 61 for mainkaining alignment
during valve operativn. The valve member 81 ls provided
with an annular seal 83 which c~operates with the end-face
84 o the inner-body part 71. Upon a pre-set pressure -~
differential occurring by pressure rise within the pressure
conduit 17~ the bellows 73 moves to hring the annular ~eal ~-~
83 into sealing engagement with the face 84. As a result,
conduit 61 is sealed to fluid flow. In a similar manner,
the bellows 73 carries a valve member 86 which projects into
; the outlet chamber 78 with an aligning pin 87 extending into
. . .
the conduit 62. An annular seal 88 carried upon the valve
- memher 86 coacts with the end face 89 of the outer body
par~ 72 to close conduit 62. As a result, the bellows 73
is protected from excessive pressures of the emulsion. With
.
this check valve arrangement, excessive fluid pressures
across the bellows 73 cannot disrupt the fluid barrier be-
,
twe~n the emulsion and the dielectric liquid.
Referring again to Figure 1, the pressure conduit
17 connects in a fluid-tight relationship to the externa~l
power source at its high voltage output. For this purpose,
tpe high voltage~output of the power source 16 is avail~ble
at a flange 91 which is secured to a complementary flange 92
,
on the pressure conduit 17. It is not desirable to con- -
struct the power source 16 with a container sufficiently
strong to withstand the pressure of the emulsion in the
vess~l 12. Preferably, a high voltage feed-through insulator ~ ~;
17 ~ ~
1~3~
93 is interposed in the pressure conduit 17 to protect the
power source l6 from the pressure of the emulsion within the
vessel 12. The feed-through insulator 93 can be carxied by
the flange 91 on the power ~ource 16.
The feed-through insulator 93 has two basic re-
~uir~ments. First, it must carxy in an insulated relation-
ship the high potential current from the power source 16 to
the cable 27 within the pressure conduit 17. Second, the
feed-through insulator must provide a fluid-tight seal be-
tween the pressure conduit 17 and the power source 16~ For
these requirements, suitable high voltage insulating mater-
ials are employed, and the fLuid ~eal i9 provided mechanical
or fluid-actuated sealing members.
The feed-through insulator 93 is shown in Figure
4 with mechanically actuated seals. The feed-through in- -
sulator 93 has a cylindrical body '34 with internal threaded
ends 96 and 97. An insulatiny sleeve 98 within the body 96
receIves the various sealing and insulating parts of the
feed-through insulator 93. More particularly, the cable 27
passes through a compression nut 99 which engages ~he threaded
end 96 for longitudinal movement relative to the body 94.
The cable 27 terminates at an upset or flanged ferrule 101.
Th~ conductor 28 of the cable 27 is received within a com-
plementary opening in the ferru:Le 101 and silver soldered
thereto to provide proper electric contact. The cable 102
is received within flange 92 and carries a conductor 103 to
the high voltage output of the power source 16. The conduc-
tor 103 is received within a complementary opening in the
fexrule 101 and silver soldered thereto for proper elec~ric
cont~ct. The flangé 9~ carries a threaded portion 104 whlah
~ ~ 18
: ' ,
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~353~9
e~gages the threaded end 97 of the cylindrical body 94.
Annular insulator 106 surrounds the ~errule 101. Insulating
and packing members 107 ~nd 108 cooperate with the packing ~
nut 99, and insulating members 109 and 110 cooperate with ~-
~he flange 92. The sleeve 94 threads between complementary
right and left hand threads of nut 99 and threaded portion
104 to place the packincJ rnembers and ferrule 101 into com-
pression thereby providing the ~luid-tight seal at the end
of the pressure conduit 17 adjacent the power source 16.
The mentioned packing and insulating members may b~ of any
suitable materials. However, a plastic material similar to
the tubular member 23 is preferred for purposes of the pre~
sent electxic treater system. The sleeve 98 can be formed
of the same plastic material, if desired.
Referring to Fig. 5, an alternate form of mechan-
ically-actuated seals in ~eed-through insulator 111 is shown.
The pressure cvnduit 17 connects through flange connections
91 and 92 to the external power source L6. ~he flange 91
contains a tubular member l:L~ which extends into the interior
~, . .
of the power source 16. A m0tal adapter 113 having a tapered
opening 114 formed centrally thereof threads into the end
of the member 112. The opening 114 coaxially carries an
in~:ulator 116 which may be formed of the same plastic in-
sulating material as the tubular member 23. However, other
.
materials such as ceramics or various inorganic insulative
mater,ials may be employed. The insulator 116 has a central
opening to receive conductor rod 117 which extends to the
interi~r of the power source 16. One end of the rod 117
carrys an enlarged wedge 118 which interfits within a com-
plementary opening in the insulator 116. ~he rod 117 at its
19
~3S3~ 9 ~:
other end traverses a metal adapter 119 threaded onto the
insulator 116. The metal adapter 119 provide~ a keyed (non-
xotating) retention of the rod 117 in the lnsulator 116.
A compression nut 121 threads onto khe end o rod 117 ~or
tensioning the wedge 118 in fluid-tightnes~ wi~hin the in- :
sulator 116. A metal cap 122 encloses the nut 121 and has ~
a terminal 123 connected to the high voltage output of the .-
external power sourae 16. ~.he ca~le 27 terminates at tha . .
feed-through insulator 111 and the conductor 28 is secured ~.
to the wedge 118 in a complementary opening by set screw ;
124. In this manner high pc.tential current can be passed --~
~ th~ough the feed-through insulator 111 and the conductor ~8
:. to.~he energized electrode 14. The insulator 111 also seals
the ~nd of condui~17 against the emulsion's pressure in
ve~sel 12.
I Mechaniaally energized fluid seals in the~feed-
::~ through insulators:make it desira.ble that the temperature
. at the pressure conduit 17 and the power source 16 ends of
~`~ . such insulators be maintained at substantially the same
temperature, whiah temperature is usually the ambient tem-
perature of the~environment surrounding the electric treater
sy tem. For this purpose a heat exchanger is associated
with the pressure~conduit 17, and preferably, it is posi- :
tioned adjacent~the~feed-through insulator. The heat ex- :
ohanger is arranged to maintain the feed-through insulator -~
.at substantiaLly the same temparature at its pressure co~
: duit and power source terminals. For example, the pressure
conduit 17 may be constructed with an integral heat ex~
changer. However, externally mounted heat excha~gers can
30 be e~ployed on the conduit 17, such as the finned tubing .:
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~l~53~79
126 shown in Figure 1. Finned tubing i~ sati~actory ~or
the most purposes since the amount of heat energy trans
ferred relative to the pxessure conduit 17 and pow~r source
terminals of the insulators is relatively of ~mall magnitude.
Circulating ambient temperature air is su~ficient to tran~-
fer the require~ he~t energy or most applications of the ;~
present invention. In some high temperature environment~,
it might be desired to provide the heat exchanger with a
liquid cooling.
The feed-through insulator can be provided with
1u1d actuated seals. More particularly, the flu,id actuated
seal~ operate from~the pressuriæed dielectric liquid within
the conduit 17. Referring to Figure 6, an embodiment of
' ~he present electria treater system employing fluid actu~! I5 ated seals in the feed-through insulator 131 is shown. InFigure 6, like elements and like parts will be given numeral
desLgnations corresponding to Eligure 1. Feed-through in-
su~a~or 131 is secured to the conduit 17 ~hrough the tee~
67 and aonduit 130.~; A flange 132 connects the insulator
~ 131 to the~flQnge 91~carried by the power source 16. The
feeæ~through insulator 131 receives actuating pre sure from
a conduit 133, which connects to the tee 63, a four-way tee
~ 134 and a conduit 136. The valve 68 can be aonnected to
!
I the ~ee 134 for introducing dielectric liquid and~ventingl 25 ~ o~gasses from the pressure conduit 17. The tee 134 also`
-:
corlne~ts to the tee 67~ in the pressure conduit 17 ~for pur-
poBes o~ fil~ling, and ~enting of flulds from, the pressùre
conduit l7.~ ~With this arrangement,~the~barrier 59 not only
equaIizea the~pressure bétween the dieleatric liquid within ~ :
the ~onduit 17 and the emul~ion within the ~essel 12 but
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~53~
also applies the dielectric liquid through the conduit 133
and 136 to actuate the fluid seals ~n feed-through insulator
131.
Referring ~o Figure 7, a detailed de~cription
of the fe~d-through in~ulator 131 will be given. 'rhe feed- :;
through insulator 131 has a body 137 which carxies the
flange 132. The ~ody 137 has formed therein a cylindrical
chamber 138 in communicati.on wi~h the conduit 136 for re-
ceiving pressurized~dielectric liquid. An axial opening .
139 within the body 137 receive~ the cable 27 which exte~ds
; through the feed-~hrough insulator 131 to the high voltaglsou~put within the external power source 16. A ~luid actu-
ated seal 141 resides within the chamber 138 and longitudin-
ally embraces the cable 27. The ~eal 141 may be of a re-
silient, but high electrical resistance, plastic material
such as TFE polymer. In addition, the seal 141 has lib end
.~ ~
por~ions I42 and 143 embracing the ends of the chamber 138. :~The flange 132 is interconnected by threads 144 to the body
137 ~o permLt acce s to the cha~sr 138 for installing the :
seal 141. The end portions 142 and 143 are held against
the interior sidewalls of;the chamber 138 by annular springs
146 and 147 to provide sufficient pre compression engage-
menk that a fluid actuated seal is obtained upon introduc- ~tion of the dielectric liquid into the chamber 138. ~ ~;
The.pres~urized dielectric liquid wi~hin the ..
~ ch~mber 138 causes the seal 141 to embrace the cable 27 - :
.: in fluid-tlghtnes~. Also the end portions 142 and 143.are
~ distended in~o fluid-tight engagement with the body 137 and
- the flange 132. The cable 27, the seal 141 and dielectric
-~ 30 liquid provide the electrical isolation of the conductor 28
~ ' ',
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:~S3~79
from the metal portions associated with the pre~sure conduit
17 and insulator 131.
II1 many cases, a fluid seal in the in~ulator 131
is desirad at a greater pre~sure than the d1electria liquid
within the pressure concluit 17. For this purpose, in refer- ~'
ence to Figure 6, a fluid ampliier 151 is inse~rted between
the conduits 133 and ~36. The ~luid amplifier 151 may be
o~ any construction~o produce in the conduit 136 a pre-
' determined corresponding increase in pressure over the di~
; 10 electric liquid that is contained~in the conduit 17.
;~ In Figure 8j one embodlment o~the f1uid ampl1fier
~ 15~ i~ shown. The ~luid amplifier 151 has a bod~ lS3 en-
, . . .
, closing a cylindrical op~rating chamber 152 with an inlet
conn~cted to the conduit 133 and an outlet connected;to the
cor.duit 136. A piston assembly 154 is~ mountad~for recipro~
ca~ion within the body~153, aDd ca.rries ~a~ first; piston 156
wlt~in the~chamber 152~and,a second piston 157 within an
u~et chamber 158.~ The piston 156 is 1arger in~diameter
ha~,the pi~ston 157~by~the:desired~presgure increase~magni-
20~ tude in the dielectric liquid in the outlet cha~ber 158
'~ ~ relative to the chamber 152. The piston 156 is,sealed to
the sidewalls of the chambèr 152 by 1l0ll ~ings 155. In~ a
like manner, the piston`l57~is'sealed to the sidewalls~of ~/,-
th~e~hamber ~lsa ~by "O"~Ring~159~ he chamber 152 has vent~ ~
pl~qs l61 and 162 so that both sides of the piston 156 in ~ ,;
ch~mber may~be vent6d and~;completely filled with dielectr'ic
liquid.~ he chamber~l52 behind the pLston 156 al60 connects
with a reservior 164 to allow dielectric liquia to flow
into a~d ou~of~chamber~152~from behLnd pLston~156. Th
, res~vior 164 may be o~a pneumatic balance accumulator
~: : : ~: : .
23 ~ ~:
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~S3~7~ :
design. The outlet chamber 158 al o has a vent plug 163 ~ :.
to insure that dielectric liquid completely fills the cham-
ber 158 and the condui1: 136 in communication with the feed-
through in~ulator 131~
The embodiments of the electric tr~ater system
heretofore described provide a ~ystem wherein neither the
entrance bu~hing 18 nor the feed~through insulators 93 eta.
are re~uired to withstand elevated pressures and high tem-
peratures simultaneously. In the entr~nce bushing 18 on
the vessel L~, the luid-tight seals between th~ tubular
member 23 and the metal adapter 21 are exposed to only in-
significant pressure differentials. The t~bular memher 23
is maintained at substantially the same temperature through-
out i.ts length, and that temperature is ~ubstantially that ;;
o.the emulsion contained within the vessel 12. The feed-
through insulator 93 etc. adjacent the external power source :~
16 withstands the full pressure o~ the emulsion within the
ve~sel 12. However, the insulator is maintained at the
same ~ambient~ temperatuxe at its pressure conduit 17 and
high v~ltage output ends.
.
For example, the entranoe bushing 18 can operate `~
under conditions which impose a temperature o S00F. while
suEferiny practically no pressure diferential between the ;~
emulsion within the vessel 12 and the dielectric liquid . : :
25 w~ithin the conduit 17. The ~eed-through insulator associated
: with the pressure conduit 17 may contain a fluid pressure -:
of five hundred pounds while being maintained at ambient ~ .
temperatures of about 80F. Thi~:separation of the tempera-
t~e and pressure operating conditions a~ the entrance bush-
ing ~nd feed-through insulator permits a system which can
:
; . ~ 24
lQ~ 79
operate at elevated temperatures and high pressures with
the same safety as if the system wers operated with a single
entrance bushing or in!~ulator containing essentially zero
flui~ pressure at ambient temperatures. Thus, ~he out-
standing safety and operating records of earller entrancebushings employed in electric field treaters are maintained
. for operating conditions of temperature and prPssure greatly
,, in the excess of those her.et.ofore enaountered in oil re-
fineries and other installations by using the present elec-
tric treater system. ,~
'~ From the foregoing, it will be apparent that
there has been provided a system ~or electrical resolution
of.emulsions which is well adapted to satis~y the purpo~es
~ of the present invention. Vari.ous changes may be made to
.' 15 the system without departing from the saope, of the appended
c~aims. The foregoing description is to be taken as ilIu-
strative of the present in~ent~on. ~
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