US1989104A - Method of and apparatus for maintaining dielectric properties of a nonconductive medium - Google Patents

Description

Jan. 29, 1935. E. MENDENHALL ET AL METHOD OF AND APPARATUS FOR MAINTAINING DIELECTRIC PROPERTIES OF A NONCONDUCTIVE MEDIUM Filed Oct. 10, 1931 N/MLL u/v/as 5 V4 A /V,

yIlIll Il Iii Patented Jan. 29, 1935 UNITED STATES PATENT OFFICE Earl Mendenhall and Junius B. Van Horn, Los Angeles, Calii., assignors to Menhorn, Inc., Los

Angeles, Calif., a corporation of California Application October 10, 1931, Serial No. 568,192

13Claims.

Our invention relates to a method of and apparatus for maintaining the dielectric properties of a non-conductive medium, and is particularly applicable to oils employed with electrical apparatus which is either submerged or in an inaccessible position.

In motors containing oil and placed in an inaccessible position or submerged, as in a well, any particles of moisture which become mixed with the oil tend to diminish the dielectric strength of the oil and to impair the efiiciency of the electrical apparatus. It is a corresponding purpose of our invention to provide a method of and apparatus for removing particles of water from the oil in which such an electrical apparatus is submerged.

Inasmuch as the space occupied by electrical apparatus disposed in a well must be kept to a minimum, it is a purpose of our invention to provide a method of maintaining the dielectric properties of oil which requires only such apparatus as may be contained in an extremely small space.

More particularly, it is a purpose of our invention to provide an apparatus for maintaining the dielectric properties of oil which includes the positioning of a hygroscopic medium in contact with the oil.

Our method of maintaining the dielectric property of oil contemplates the positioning of a body of material having an afllnity for water in contact with the oil, and the circulation of the oil relative thereto.

In the drawing, which comprises a vertical cross-sectional view of the apparatus of our invention, in order to illustrate the advantages and utility of our invention, we have shownthe particular embodiment of our invention which is adapted for use with electrical motors disposed adjacent the bottom of a well for operating a pump.

Referring to the drawing, which is for illustrative purposes only, the numeral 11 indicates a cylindrical casing positioned near the lower end of a well 12. Contained in the upper portion of the casing 11 is an electrical motor 13 which includes a stator 14 and a rotor 15, the rotor 15 being non-rotatably secured to a vertical shaft 16. The lower end of the shaft 16 is supported in a journal member 17 attached as by arms 18 to the inner surface of the casing 11. Disposed above the motor 13 is a second journal member 20 surrounding the shaft 16 and supported by arms 21 attached to the inner surface of the casing 11.

Positioned in the casing 11 above the journal is adapted for rotation within an impeller bowl 28.

so that upon rotation of the impellers liquid is forced from the impeller bowls 28 upwardly through an outlet pipe 29 in a manner well known in the art. The fluid thus pumped is drawn from the exterior of the casing 11 through openings 30 provided in the casing 11 above the top member 22.

Attached to the casing 11 below the journal member 17 is a battle member 31 having openings 32 therein, this baiile member dividing the interior of the casing 11 into a motor chamber thereabove and a balance chamber therebelow. The lower end of the casing 11 may be closed ofi as by an end member 33, the interior of the casing 11 communicating with the exterior thereof through an opening 34 adjacent the end member 33. If that portion of the casing 11 between the top member 22 and the end member 33 be substantially filled with oil of high dielectricstrength, and the unit thus described be disposed in a well and submerged in water or a liquid containing water, this liquid enters through the openings 34 in the casing and exerts upon the oil contained within the casing 11 an upward pressure equal to the downward pressure exerted by the liquid entering the casing 11 through the openings 30 above the top member 22. The pressure on the lower side of the packing is thus made substantially equal to the pressure on the upper side of the packing so that the tendency for the liquid above the top member 22 to enter through the packing member 25 and mix with the oil within the casing 11 is practically eliminated. The fluid from thevexterior of the casing 11 which enters through the openings 34 assumes a quiescent level indicated by the numeral 35'representing the surface of contact of the two liquids. It should be evident that a considerable volume of the oil may escape from the casing 11 before the level 35 of the fluid containing water has approached near enough to the motor 13 to become dangerous.

However, some of the particles of water from below the level 35 may become mixed with the oil contained within the casing 11. Likewise, some particles of water may enter this oil through the packing 25 or any small leak in the casing 11. Similarly, there may be present in the casing 11 particles of water which were present in the casing 11 when the casing was filled with oil, or which condense on the walls of the casing during the filling of the casing. To remove these particles of water from the oil contained within the casing 11, we provide upon the upper surface of the bafile member 31 a container 36 which may be in the form of a closely woven scr'een. Retained in the container 36 is a body of material 37 having hygroscopic properties. This material may be calcium chloride, plaster of Paris, trade compounds such as Silica-Gel, cements, or any such medium having an afiinity for water. The oil within the casing 11 being circulated by the rotation of the rotor 15, any particles of water contained therein are brought soon after theirentrance into the oil into contact with the body of material 37 and, because of the hygroscopic nature of the material 37, these particles of water are thus removed from the oil contained within the casing 11.

By providing the bafiie member 31 with the openings 32, the fluid from the exterior of the casing 11 which enters the casing 11 through the openings 34 is permitted to exert upon the oil within the casing 11 above the baffle member 31 a pressure equal-to the pressure on the exterior of the casing 11. However, since the communication between that portion of the interior of the casing above the'baflie member 31 and that portion of the interior of the casing below the baflie member is accomplished only through the openings 32, the circulation of oil caused by the rotation of the rotor 15 is prevented from creating a sufiicient turbulence of the oil below the baflle member 31 to cause an agitationwhich would allow a harmful amount of the water entering through the openings 34' to become mixed with the oil in the casing 11. The relative proportion of the hygroscopic material 37 and the oil contained within the casing 11 may be varied to provide for the needs occasioned by the type of electrical apparatus employed and the conditions under which it is used.

In order to illustrate the utility of our invention we have referred to the conductive medium as water, and the non-conductive medium as oil. We wish it understood that these media have been referred to for illustrative purposes only, and that our invention includes the use of other conductive and non-conductive media as well.

While that embodiment of our invention hereinbefore illustrated and described is fully capable of performing the objects and providing the advantages primarily stated, there are other embodiments of our invention likewise capable of performing these objects and providing these advantages, and we therefore wish our invention to be understood as not restricted to the specific embodiment hereinbefore set forth.

We claim as our invention:

1. The method of drying an oil of high dielectric strength and positioned around an electric motor which includes the positioning of a body of hygroscopic material therein and circulating said oil relative to said body and in'cooling relationship with said motor.

2. A method of maintaining the dielectric properties of a dielectric oil around an electric motor and having access to a conducting liquid, which method includes the steps of: positioning in said oil a body of material having an affinity for said conducting liquid; circulating said dielectric oil in cooling relationship with said motor adjacent said body of material whereby any of said conducting liquid entering said oil becomes associated with said body of material; and retaining said body of material and its associated conducting material in fixed position to prevent any of said material and its associated conducting liquid from being dispersed in said dielectric liquid.

3. A method of maintaining the dielectric properties of a dielectric oil around an electric motor and in surface contact with a conducting liquid, which method includes the steps of: retaining a body of hygroscopic material in fixed position in said body of dielectric oil; and circulating said dielectric oil to move same into contact with said body of hygroscopic materialand in cooling relationship with said motor.

4. A method as defined in claim 3 in which said body of hygroscopic material is positioned insaid dielectric oil in spaced relationship with the surface of contact between said dielectric oil and said conducting liquid, and including the step of shielding the surface of contact from the stream of dielectric oil thus circulated in cooling relationship with said motor to prevent agitation at said surface of contact which would cause additional intermixture.

5. In combination in a submersible electric motor: a casing surrounded by a conducting liquid and containing a body of dielectric liquid having access to said conducting liquid whereby minute particles of said conducting liquid may become associated with said dielectric liquid; a shaft extending through said casing to a point exterior thereof; sealing means at the junction of said shaft and said casing; means for rotating said shaft and circulating said dielectric liquid, said means including an electric motor positioned in said dielectric liquid; and a. mass of hygroscopic material having an affinity for said conducting liquid and positioned in said casing and in the path through which said dielectric liquid is circulated.

.6. A combination defined in claim 5 including an interstitial container positioned in the path through which said dielectric liquid is circulated and containing said mass of hygroscopic material.

7. In combination in a submersible electric motor: a casing surrounded by a conducting liquid and containing a body thereof, said casing also containinga body of dielectric liquid in surface contact with said body of conducting liquid; an electric motor positioned in said body of dielectric liquid; and a mass of hygroscopic material positioned between said motor and the surface of contact of said bodies of said dielectric liquid and conducting liquid and having an affinity for said conducting liquid to. remove from said dielectric liquid any of said conducting liquid entering therein before the contaminated dielectric liquid moves into contact with said motor.

8. In combination in a submersible electric motor: a casing positioned in a conducting liquid and containing a dielectric liquid; baflie means in said casing and dividing the interior thereof into a motor chamber and a balance chamber, said bal ance chamber containing contacting bodies of said conducting liquid and said dielectric liquid, said baflle means defining an opening through which said motor chamber and said balance chamber are in communication with each other; a shaft extending from'said casing; means for rotating said shaft and circulating said dielectric liquid in said motor chamber, said means including an electric motor driving said shaft, said bailie means preventing the circulation of said dielectric liquid which takes place in said motor chamber from agitating said contacting bodies of said liquids in said balance chamber; and means retaining a mass of hygroscopic material in said body oi dielectric liquid in the path of movement 01' said dielectric liquid, said hygroscopic material having an amnity for said conducting liquid.

9. A combination as defined in claim 8 in which said last-named means includes a container in said motor chamber and positioned in the path 01 the dielectric liquid circulating in said motor chamber and including a mass of hygroscopic material retained in said container and having an aflinity for said conducting liquid.

10. A method of maintaining the dielectric properties of a dielectric oil positioned in a motor shell containing a motor and having access to a conducting liquid, which method includes the steps of: submerging said motor shell in said conducting liquid; positioning in said motor shell a .body of a material having an aflinity for said conducting liquid; and circulating said dielectric oil "1 a closed circulation path during which flow said oil moves adjacent said motor in cooling relationship therewith and adjacent said body of material whereby any of said conducting liquid entering said oil becomes associated with said body 0! material and is thereby kept from reaching said motor.

11. A method of maintaining the dielectric properties of a dielectric oil positioned in a motor shell containing a motor and having access to a conducting liquid, which method includes the steps of: submerging said motor shell in said conducting liquid; positioning in said motor shell a body of a material having an amnity for said conducting liquid; circulating said dielectric oil in a closed circulation path during which flow said oil moves adjacent said motor and adjacent said body of material whereby any of said conducting liquid entering said oil becomes associated with said body of material and is thereby kept from reaching said motor; and retaining said body of material and its associated conducting material in fixed position to prevent any of said material and its associated conducting liquid from being dispersed in said dielectric liquid and reaching the working parts of said motor.

12. In combination in a submersible electric motor: a casing containing a dielectric liquid and submerged in a conducting liquid of higher electric conductivity than said dielectric liquid; an electric motor in said casing and including a rotor and a stator; a shaft operatively connected to said rotor and extending from said casing; a semieifective seal at the junction of said shaft and said casing and providing end portions respectively communicating with said dielectric liquid and said conducting liquid, a movement of said shaft forming an intermixture of said liquids at said seal; and means in said casing for removing from said intermixture said conducting liquid, said means returning the purified dielectric liquid of said intermixture to said dielectric liquid in said casing.

13. In combination in a submersible electric motor: a casing containing a dielectric liquid and submerged in a conducting liquid of higher electric conductivity than said dielectric liquid; an electric motor in said casing and including a rotor and a stator; a shaft operatively connected to said rotor and extending from said casing; a semiefl'ective seal at the junction of said shaft and said casing and providing end portions respectively communicating with said dielectric liquid and said conducting liquid, a movement of said shaft forming an intermixture of said liquids at said seal; and means in said casing for removing from said intermixture said conducting liquid, said means returning the purified dielectric liquid of said intermixture to said dielectric liquid in said casing,

.said means including a body of material having an afllnity for said conducting liquid, the rotation of said rotor circulating said intermixture into the vicinity of said body of material.

EARL MENDENHALL. JUNIUS B. VAN HORN.

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