Conductive fluid resolver

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31 - 1 SR S.A. i.

April 6, 1965 W. L. CARLSON, JR 3,177,383

Conductive flud resolver

Filed Sept. 20, 196l

Conductive

Fluid

Electrc

Source

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- E. S. retressee seceaser Eric Er

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William A. Caelsom, Vk.

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United States Patent Office 3,177,383 Patented Apr. 6, 1965 electromagnetic conductive fluid type as opposed to a

CONDUCTIVE FLUD RESOLVER piston pump or circulator type pump that uses a mechani William L. Carlson, Jr., Bloomington, Minn., assignor to cal pumping action.

Honeywell Inc., a corporation of Delaware In FIGURE 2 an elevation along the line 2-2 of FIG Filed Sept. 20, 1961, Ser. No. 139,471 URE 1 is disclosed wherein the resolver 14 is shown in de 6 Claims. (C. 310-11) tail. The output wires 15 are shown connected to the resolver and will be described in some detail after the

The present invention is directed to a resolving device present description. The pipe 12 is shown split at 16 capable of sensing rotation, and more particularly is di and 17 to provide two electrodes 20 and 21 formed as rected to a conductive fluid filled device that utilizes the O two opposite walls of the pipe 12. The splits 16 and 17 concept that an electric current is generated in a conduc in the pipe 12 form the electrodes 20 and 21 to provide tive fluid when the fluid is subjected to mutually perpen two semicircular electrode surfaces when viewed in cross dicular magnetic fields and fluid flow. Section. The section of pipe 12 where the splits 16 and It has long been known that an electromagnetic conduc 17 occur is encased in an insulating material 22 in the tive fluid pump can be formed wherein a conductive fluid 5 form of a sleeve, that provides a fluid seal so that none of is caused to flow by an electric current and a magnetic the fluid contained in the system can leak to the atmos field angularly disposed to each other and to the direc phere.

tion of flow of the fluid. This principle was recognized The details of the sleeve 22 can be more fully under by Faraday. The basic principle has been applied to many stood when the cross section of FIGURE 3 is considered. types of devices such as pumps, flowmeters, and, in some 20 The insulating sleeve 22 extends beyond the splits 16 and cases, generating devices wherein a constant magnetic field 17 and is sealed by a pair of cap members 23 and 24 along is mutually perpendicular to a flowing conductive fluid with a pair of O-rings 25 and 26. The O-rings fit tightly and a pair of electrodes. The present invention is direct about the pipe 12 and the cap members 23 and 24 are ed to the utilization of these well-known principles in a Screwed down or otherwise appropriately sealed to the in specific device to yield a resolver that is capable of sensing 25 sulating tube 22. The insulating tube 22 could readily a rotational angle and which has no restoring torque gen be made of glass or a ceramic and provide a hermetic erated by the rotation of the device. seal so that the slots 16 and 17 would not leak any of the It is a primary object of the present invention to dis conductive fluid contained in the device. The wires 15 close a conductive fluid resolver that utilizes a flowing can be seen passing through insulated seals 30 and 31 and conductive fluid in a system that contains two fixed elec 30 being attached at 32 and 33 to the electrodes 21 and 20, trodes and a rotatable magnetic field wherein a variable respectively. The wires 15 thus provide electrical connec output signal is generated by the relative rotation of the tions to the electrodes 20 and 21 so that any potential field to the electrode structure. generated between these electrodes can be brought out as It is another object of the present invention to dis an electrical output signal for a resolver. close a closed fluid system that is capable of generating 35 Returning to FIGURE 2, it will be noted that the re an electrical output that is related to the position of one solver has a magnetic structure 34 that is made up of a of the elements and which varies in a sinusoidal fashion. pair of permanent magnet pole pieces 35 aind 36 that Yet another object of the present device is to dis project inwardly from a yoke 37. The yoke 37 is made of close a mechanical resolver that is capable of sensing a a good magnetic material and in turn supports a bearing rotational position and which has no restoring torque 40 race 40 that is used to support the magnetic structure 34. generated when the resolver is utilized. The pole pieces 35 and 36 are rounded at 38 and 39 so These and other objects will become apparent when that they maintain a uniform air gap around the insulating the device is fully considered in the light of the present tube 22 and provide a magnetic field across the tube 12. specification and drawing, wherein: In the position disclosed in FIGURE 2, a magnetic field FIGURE 1 is a schematic representation of a typical 45 would exist at right angles to the electrodes 20 and 21 system including the resolver and the pump means for cir and this magnetic field would be mutually perpendicular culating a conductive fluid; to the electrodes and the direction of flow of the conduc FIGURE 2 is a cross section along lines 2-2 of the tive fluid contained in the system. As such, an electrical resolver disclosed in FIGURE 1, and; potential would be generated between the electrodes 20 FIGURE 3 is a cross section of the resolver in a plane 50 and 21 and would be available on the conductors 15. perpendicular to that of FIGURE 2 and taken along lines Four ball bearings 41 and four bearing blocks 42 are 3-3 of FIGURE 2. disclosed supporting the magnetic structure 34 by rolling The over-all system of FIGURE 1 includes a pump in the race 40 in a groove 43. The bearing blocks 42 means 10 that has been disclosed as a conductive fluid are supported by appropriate structure so that the ball pump. The pump means 10 can be of any type, but the 55 bearings 41 roll in the slot 43 of the race 40 thereby allow use of an electromagnetic conductive fluid pump having ing the magnetic structure 34 to rotate with the center no moving parts simplifies the over-all construction. The of the pipe 12 as the center of rotation. With this ar conductive fluid pump 10 is supplied by an electric power rangement it is possible to freely rotate the magnetic struc source shown connected to conductors 11 and the pump ture 34 around the electrode structure 20 and 21 thereby operates into a closed pipe system 12. A conductive fluid 60 changing the angle at which the magnetic field from the resolver is shown generally in elevation at 14 and forms poles 35 and 36 cross the electrodes. If the magnetic the closing link in the conductive fluid system. The re structure 34 were rotated to a position where the magnetic solver 14 has an electrical output signal on a pair of con field from the poles 35 and 36 crossed the electrodes 20 ductors designated as 15. and 21 at right angles to the slots 16 and 17, there would The fluid system is filled with a conductive fluid, and 65 be no electrical output from the conductors 15 as there can be considered such a fluid as mercury or an alloy of would be no angular difference between the electrode cen sodium and potassium commonly referred to as NaK. ter and the center of the magnetic field. The conductive fluid is continuously pumped by the pump The output of the resolver 14 is a function of the posi means 10 through the system and in most applications tion of the magnetic field between the poles 35 and 36 would be flowing at a constant rate. In order to obtain 70 as long as the rate of flow of the conductive fluid in pipe the constant even flow of the conductive fluid, the con 12 remains constant. As such, as the magnetic structure ductive fluid pump means 10 would normaly be of the 34 is rotated about the pipe 12, the output of the resolver 3 on conductors 15 will vary from a maximum in the posi angles to said electrode means and a minimum when said tion shown, to a minimum when the magnetic structure field is in line with said electrode means. has been rotated 90 degrees. The output would then be 2. In a conductive fluid device for converting rotational gin to increase again as the structure was continued to movement into an electrical signal output: flow system be rotated but the output would be of a reverse polarity. means filled with a conductive fluid; pump means moving It can thus be appreciated that a positional signal output said conductive fluid in said system at a substantially can be derived on conductors 15 by rotating the magnetic constant rate and a portion of said system being annular structure 34 around the electrodes 20 and 21. In order in cross section; electrode means oppositely disposed at to provide the rotation of the magnetic structure 34, a said portion and including external connection means drive wheel 44 is provided that rides in the groove 43 and O electrically connected to said electrode means; and mag the drive wheel is centered around a shaft 45. The drive netic field generating means mounted for rotation around wheel 44 further has a gear 46 that drives a second gear said portion and providing a magnetic field across said 47 around a shaft 50. It is thus apparent that a mechani portion that can be rotated with respect to said electrode cal input can be provided for rotating the magnetic struc means; said magnetic field interacting with said flowing ture 34 and that the rotation will cause a change in signal 5 fluid to generate an electrical signal output as a positional output on conductors 15 as a function of the position of function of the rotation being a maximum when said field the magnetic structure with respect to the electrodes 20 is at right angles to said electrode means and a minimum and 21. One of the most important features of the pres when said field is in line with said electrode means. ent device is the fact that in generating an output signal on 3. In a conductive fluid device for converting rota conductors 15 by causing a movement of the gear 47 to in 20 tional movement into a positional electrical signal out turn rotate the magnetic structure 34, there is no force put: flow system means filled with a conductive fluid; generated which tends to return the structure to its original pump means moving said conductive fluid in said system position. As such, the device is unique and differs from at a Substantially constant rate of flow and a portion of conventional electrical rotating devices that have a back said System being annular in cross section; electrode electromotive force that tends to restore the device to 25 means oppositely disposed at said portion and including its original position. The output signal on conductors 15 external connection means electrically connected to said is completely independent of anything beyond the flow of electrode means; and magnetic field generating means the conductive fluid and the position of the magnetic field mounted for rotation around said portion and providing a and, without a restoring torque applied by the generating magnetic field of substantially constant magnitude across action, the device can be rotated by an input to the gear 30 said portion that can be rotated with respect to said elec 47 without making any corrections or retaining any input trode means; said magnetic field interacting with said force in the gear system to compensate for any back flowing fluid to generate a positional electrical signal out E.M.F. that would normally be generated in a conven put as a function of the rotation being a maximum when tional unit. said field is at right angles to said electrode means and a In order to avoid short circuiting any of the generated 35 minimum when said field is in line with said electrode potential between the electrodes 20 and 21, the slots 16 means; said electrical signal reversing in polarity as said and 17 are extended to points 51 and 52 which are well magnetic field generating means is rotated in one direc outside the area of the magnetic field supplied around or tion around said electrode means. to the system. As such, the electrodes 20 and 2 appear 4. In a conductive fluid device for converting rota to be completely isolated electrodes and if the tubing pro 40 tional movement into an electrical output: flow system vided for the conduit 12 is made of a high-resistance means filled with a conductive fluid; an electromagnetic material, such as a high-resistance steel, little or no shunt conductive fluid pump moving said conductive fluid in said ing from one electrode to the other occurs in the present system at a substantially constant rate of flow and a por device. If need be, the present device could be con tion of said system being annular in cross section; elec structed with independent electrodes 20 and 21 that are 45 trode means oppositely disposed at said portion and in Supported within the insulating tube 22. This could be ac cluding external connection means electrically connected complished readily by cutting out the electrodes 20 and 21 to said electrode means; and magnetic field generating and mechanically attaching them to the tube 22 or by plat means mounted for rotation around said portion and pro ing a conductive surface on an insulating tube 22. Since viding a magnetic field across said portion that can be many modifications in the electrode structure would be rotated with respect to said electrode means; said mag possible without deviating from the present invention, the 50 netic field interacting with said flowing fluid to generate specific electrode structure has been disclosed in a broad an electrical output as a positional function of the rota ac. tion being a maximum when said field is at right angles It is obvious from a consideration of the present dis to said electrode means and a minimum when said field is closure that many modifications, such as modifications in 55 in line with said electrode means, the electrode structure, could be undertaken and that these 5. In a conductive fluid device for converting rota modifications would be well-known to ones versed in the tional movement into an electrical output: flow system art. As such, the applicant wishes to be limited in the means filled with a conductive fluid; pump means moving scope of the present invention only to the scope of the said conductive fluid in said system at a substantially appended claims. 60 constant rate of flow and a portion of said system being I claim as my invention: annular in cross Section; said annular portion being slotted 1. In a conductive fluid device for converting rotation at diametrically opposite sides to provide two electrodes all movement into an electrical output: flow system means at said portion; said electrodes having an insulative hous filled with a conductive fluid; pump means moving said ing sealing said portion in a fluid tight manner, and in conductive fluid in said system at a substantially constant 65 cluding external connection means electrically connected rate of flow and a portion of said system being annular to said electrodes; and magnetic field generating means in cross section; electrode means oppositely disposed at mounted for rotation around said housing and providing said portion and including external connection means elec a magnetic field across said portion that can be rotated trically connected to said electrode means; and magnetic with respect to said electrodes; said magnetic field inter field generating means mounted for rotation around said O acting with said flowing fluid to generate an electrical portion and providing a magnetic field across said portion output as a positional function of the rotation being a that can be rotated with respect to said electrode means; maximum when said field is at right angles to said elec said magnetic field interacting with said flowing fluid to trodes and a minimum when said field is in line with generate an electrical output as a positional function of said electrodes.

the rotation being a maximum when said field is at right 75 6. In a conductive fluid device for converting rota 4 tional movement into an electrical signal output: flow line with said electrodes; said drive means rotating with system means filled with a conductive fluid; an electro said field generating means to have said mechanical drive magnetic conductive fluid pump moving said conductive means provide a mechanical counterpart to said electrical fluid in said system at a substantially constant rate; a por signal.

tion of said system being annular in croSS Section and be References Cited by the Examiner ing slotted at diametrically opposite sides to provide two UNITED STATES PATENTS electrodes; said electrodes having an insulative housing sealing said portion in a fluid tight manner, and including 2,733,604 2/56 Coutler --------------- 310-11 external connection means electrically connected to said 2,907,207 10/59 Rinia ----------------- 73-194 electrodes; magnetic field generating means mounted for 10 3,028,092 4/62 Fay.

rotation around said housing and providing a magnetic 3,034,002 5/62 Carlson --------------- 310-11 field across said portion that can be rotated with respect OTHER REFERENCES to said electrodes; and mechanical rotational drive means connected to said field generating means; said magnetic Electronics, November 27, 1959, page 82. field interacting with said flowing fluid to generate an 5 The Hall and Allied Phenomenon, by Leslie Campbell, electrical signal output as a positional function of the pages 116 and 117.

rotation being a maximum when said field is at right angles to said electrodes and a minimum when said field is in MILTON O. HIRSHFIELD, Primary Examiner.