US2354563A - Magnetic drive - Google Patents

Description

l UBB v the distance 'traveled by minimum andthe external shape is such that ice Patented July 25,` 1944 UNITED STATES PATENT orrlcs MAGNETIC DRIVE .i Frank w. n weisse, corpus camu, Tex.,-sisignor to Badger Meter Mfg. Company, Milwaukee, Wis., a corporation of Wisconsin Application April 26, 1940, Serial No. 331,828

9 Claims. (Cl. 'I3-272) This invention relates to improvements in magnetic drives as particularly adapted for meter 'libe objects of the invention include the provision of a novel. simplified magnetic drive arrangement ofthe type in which the driving member operates by rotation as distinguished from oscillation, and in which the construction is such as to transmit a maximum of energy with a minium loss ofmagnetism and a minimum loss of energy through friction. More specifically, I seek to minimize friction by completely elirninating the stuffing box and by eliminating all gearing from the connections to the driving element; so minimize corrosion, wear and sand trouble by disposing of gearing in a compartment herrnetif cally sealed; to provide for a non-slip magnetic coupling between the motor shaft and the driven register shaft, notwithstanding the elimination of gearing from the meter chamber, by an arrangement permitting the use of an extremely lightweightk keeper; to minimize magnetic losses by y the particular magnet and keeper construction employed and by the peculiar form ef the plate partition through which the magnetic drive is effected.- the partition being so designed as to present a very thin partition wall at the point of the magnetic drive and a considerably thicker wall elsewhere to provide adequate strength; and to minimise loss of magnetism from the driving element while at the same time protectingthe driving element against the possibility of damage by freezing by the use of a substantially circular magnet lof extremely small diameter, whereby the polesI is kept at a forming about the magnet will' not under any vordinary circumstances 'be able to form itself in such a way as to lock the magnet against rotation. Other objects will be apparent to those skilled in the art upon analysis of ythe following disclosure of the invention. In the drawing: n

Fig. 1 shows, partially 'm side deviation cui largely in vertical axial section. a'meter embodying this invention. l v l Fig. 2 is a fragmentary detail view. showing vin tplrspective the component'elements comprising e drive.

characters throughout the several views.

ments are separated in the usual manner by a partition at I0, apertured to receive the motor chamber Ii. It is broadly immaterial what kind of a motor is used. For purposes of illustration I have` shown a rotor Vi2 of the turbine typ'' supplied with iiuid through the ports i3,v which, in this type of meter, will usually be tangential. However, it should be understood that this driving mechanism may be applied to any liquid measuring device. Below the rotor I2 there are discharge ports Ilopening from the meter chamber ii into the outlet compartment 8 and usually likewise tangential so that the liquid traversing motor chamber Il will travel therethrough in a substantially uninterrupted vortex.

The rotor i2 is adjustably supported on a bearing screw I5. Extending upwardly from the rotor is the motor shaft I6 which carries an element of the magnetic drive hereinafter to be described.

The shaft Il. turns freely in a bushing l1, which, if made of rubber or the like, as preferred,

will be almost frictionless in the presence of the end the cup-shaped closure memberlil is nanged outwardly at 2i to iit within the bea-ring portion 22 of the meter casing l and to provide a seat for the gear casing 23. It is not necessary that the cup-shaped closure member 2l should have its interior sealed in any way from access of Ythe metered liquid thereto. It is sufiicient if there is substantially no'active flow of the metered liquid through the interior of member 20, the t of the parts being suiiiciently close so that in the absence of active flow there is little likelihood of any sand `or other foreign matter penetrating the interior of member 2l. Y-

The gear casing 23 likewise comprises a cupshaped member preferably provided with a flange 24 projecting laterally from its bottom p'rtion to provide a shoulder engaged by gasket 25 and annular metal retainer 2t under compression of the annular -nut 21 which is threaded to the exterior of the barrel portion 22 of the meter Like parts are identified by the sameireferen'celj '.50

inlet compartment l supplied through a coupling spud 1 and an outlet compartment l discharging through acoupling spud I. .'I'he two compart- `casing I..

. At its top 'the gear casing 23 is hermetically sealed by the register casing 2l, itself an her metically closed unit in which the usual cover glass 29 protected by the hinge plate 30, permitsk inspection of the conventional dials (not shown),

.driven by shaft ll and gear I2 from the gear train designated in its entiretLv by reference character Il. The register casing Il has a flange 3l whereby the annular nut Il threaded to the gear train housing. oan'exert pressure on the gasket or packing at l1 to provide a seal for the cup-shaped gear train housing 28.

The bottom wall Il of the gear train housing 2l has to be of reasonably heavy construction to resist the pressure in the interlorof the meter and to avoid distortion from any other cause, as the slightest distortion might destroy the proper iterfitting of the various parts. Yet it is important that the magnetic force relied upon to effectuate a drive between the motor shaft Il and .the gear train should be maintainedat a maximum-first, by bringing the magnet and the keeper as close together as possible, and secondly, by avoiding the losses of magnetism consequent upon rotation of any magnet in proximity to any large mass of metal.

In the particular construction herein disclosed, instead of employing a plurality of plies of metal'. I get substantially the same effect by recessing at Il the bottom wall Il of the gear train housing 23 to leave at the point where the magnetic drive is eilected a wafer-thin partition between the meter casing proper and the gear train housing. Since the driving and driven elements of the magnetic drive preferably do not exceed about one-half inch in diameter, even for meters of large size, and the recess Il is only slightly larger, it will be apparent that the desired reduction in thickness at the point of magnetic drive can be brought about without any material sacrifice of the strength of the bottom wall 40 as a whole.

The recess 4| is preferably annular. In form- -ing it an annular flange is left at 42 to confine and locate a bearing within which the driving shaft 43 of the gear train Il is supported.

It will be noted from the illustration that the gear train as a whole is exceptionally light. This is desirable in order to reduce its inertia so that at any sudden stopping or starting of the motor the keeper will inevitably follow the magnety without slip. (In the interests of this same lightness, the magnet, rather than the keeper, is preferably the driving element of the magnetic drive shortly to be described.) This lightness is made possible by the fact that no gearing whatever is located below the partition wall 40, this, in turn, being possible only because the arrangement disclosed eliminates the resistance of packing, and also eliminates resistance attributable to corrosion or to sand by hermetically sealing the entire gear train in the casing member 23.

For reasons already indicated, the magnet 45, best shown in Figure 3, is mounted on the motor shaft i6, is circular or substantially circular in horizontal plan, and has its poles Il and 41 separated only by a shallow groove at Il. In actual practice it is found that there is practically no tendency for ice forming within the meter to key itself to a magnet of this particular form in such a way as to impede the rotation of the motor shaft. The only portion of the magnet to which the ice can possibly key itself is the groove 4l between the poles. This groove is not only very small in cross section so that the ice key can readily be broken, if formed, but, in addition, the overall radius of the magnet is so small as to give the motor a very substantial increase in mechanical advantage as compared with magnets heretofore used. y,

The small diameter of the magnet, preferably. not greatly exceeding a half an inch, makes it possible for the wall thickness at the bottom of asu,

the 'Il to hel reduced without loss of strength very materially below the thickness that would be necessary if a larger magnet were employed. This'i'n turn gives the magnet the driving effect which would normally be expected only of a much larger magnet, because of the very close coupling that is possible between the magnetand the keeper, due to the extreme thinness of the partition wall at the bottom of the recess 4I. Inasmuch as this extreme thinness of the partition wall is achieved at the point where the magnet drive is effected. there is no substantial mass of metal intervening between the magnet' and the keeperand thus the loss of magnetism which would normally beexpected through rotation of the magnet in the presence of a more substantial mass of metal is avoided. Furthermore. the small diameter of the magnet also protects against loss of magnetism in that losses of magnetism are attributable not to the angular degree of rotation butto the linear travel of the magnetic poles respecting an adjacent mass of metal. Thus, by the small radius of the arm traversed by the poles Il and 41 of the magnet, .the extent of linear travel is minimized in proportion to the angular travel of the poles.

The keeper Il is attached to shaft 4l immediately below the pinion Il through which the The eilectiveness of the coupling achieved by this construction is remarkable for parts of such small radius. Under the most extreme circumstances enountered in meter operation there is no lag or slip of any kind. Even if the gear train be driven backwards to turn the keeper at a high rate of speed, and its operation is then suddenly arrested, the -lnertia of the magnet and the rotor will not be suilicient to cause any substantial overrun. It is therefore possible to interchange the keeper and the magnet, using the keeper rather than the magnet, as the driving element. It is, however, preferred to minimize ,the possibility of slippage by using the organization herein disclosed, a further advantage lying in the fact that it is easier to make the U-shaped magnet resistant'to ice stoppage than to produce the same effect with the U-shaped keeper.

I prefer that the keeper be made of very light sheet metal and that the power of the magnet be sufllciently in excess of that actually required for operation so that the keeper may, in the first instance, be completely saturated. Thus, insfar as the magnet may gradually be reduced in strength over a long period of use, the reduction will have little or no eifect on lthe amount of aux passing through the saturated keeper, thus maintaining the coupling substantially constant until the magnet has lost a very substantial portion of its original strength. I

While my improved magnetic drive has been described and its advantages indicated with particular reference to meter problems, I regard the magnetic drive as having utility for many other purposes. v l y As previously noted, the construction per- I claimz" l. Aj magnetic ,drive comprising the kcombination of 'a magnet element and a keeper element. whereof at least one of'said elements is a ydiskahapedmember substantially circular in outline for rotation upon its axis and having one oi' its ends providedwith a substantially unbroken'surface except where traversed by a single transverse groove defining separate pole portions of said member.

2. In a meter having a water confining partition. a magnetic drive through said partition comprising the combination with driving and driven elements mounted for free rotation, each of which is U-shaped to provide distinct pole portions, one of said elements disposed on the water retaining side of the partition comprising a magnetic member substantially circular in overall outline in transverse section with an end having a iren-v `eially iiatface with polesy defined by a single transverse groove, and the other of said elements, extexiorly of said partition, comprising a keeper member of light sheetv metal.

3. In a meter,l the combination with a meter casing. of an hermetically sealed gear-train casing constituting a closure forl said nrst mentioned ing adiametrical channel in a face adjacent said partition whereby to provide poles immediately contiguous to said partition, a gear train in said gear casing including a driven shaft terminating adjacent said partition in substanltial alignment with the rotor shaft, and a keeper casing and havingan unbroken wall completely partitioning the interior of the gear train cas- `ing from the interior of the meter casing. a fluid motor operable in the meter casing. a gear train operable in the gear train casing. a motor shaft leading to the proximity of said wall, a magnetic driving element mounted thereon to be directly driven from said motor,v a gear train shaft with-` in the gear train casing in substantial align- 4ment with said motor shaft, a magnetic driven element mounted on the gear train shaft in operative position to receive torque from the magnetic driving element through `said partition interveningbetween said shafts and elements. said gear train including all gearing in complete hermetic isolation from said meter casing, said partition being provided with bearing support for the gear train shaft and with an annular recess about said ybearing support reducing the thickness of said partition to a minor fraction of its thickness elsewhere, the driven magnetic coupling element comprising a keeper mounted on said gear train shaft with an onset central portion spanning said bearing and pole portions located deep in said recess, the driving coupling element mounted on the motor shaft comprising a magnet of substantially circular outline and small radius with a transverse channel in its end face defining pole portions located in immediate proximity to said partition at the side thereof opposite said ilrst mentioned recess.

4. In a meter. the combination with means providing a meter casing, a gear chamber and an intervening partition hermetically sealing said chamber from said casing, of a gear train within,

the gear chamber and having a driven shaft at one side of said partition, a liquid drive motor in the meter casing having a driving shaft at the other side of said partition in approximate alignment with the driven shaft. and magnetic driving and driven elements for transmitting motion between said shafts, one of said elements comprising a magnet and the other a keeper, the element on the driving shaft being exposed to liquid traversing the meter casing and comprising a small disk axially mounted on the driving shaft and substantiaily'diametrically channeled on a face adjacent said partition whereby to provide facial poles contiguous to said partition.

on the drivenshaft provided with poles complementary to those of said magnet to receive:

motion from said magnet for the propulsion of said gear-tram from said rotor shaft, the circular form of said magnet being adapted to enable said magnet to break itself free of any ice forming in the water in said meter casing to which said magnet is exposed 6. 'I'he combination with a water kmeter casing having inlet and outlet chambers and intervening apertured partition means. of a motor -casing seated against the partition means and having ports communicating with the inlet and voutlet chambers of the meter casing, bearing means in the motor casing, a rotor in the casing and including a driving shaft projecting ttherefrom. an annular flange extending upwardly from the motor casing enclosing said shaft and fitted to said meter casing, a closure for the meter casing engaging said flange and provided with means connecting it to the meter casing under pressure such as to hold the motor casing seated -upon said partition. meansbeyond said closure exteriorly of said meter casing providing a gear train casing henneticaily sealed from Asaid meter casing, a gear train in the gear train casing having la driven shaft substantially aligned with 'the driving shaft of said rotor at opposite sides of said closure, a disk magnet of generally circular outline mounted waally upon the end of the driving shaft and having a diametrically channeled face in immediate prox. imlty to the closure and enclosed by said ilange whereby to be isolated from the general ilow of water through said meter while exposed to water within said ilange, and a keeper carried by the driven shaft of the gear train and provided with polar terminals immediately adjacent said magnet face at the other side of the closure whereby to receivev motion therefrom through the intervening closure.

7. Ina meter, the combination` with casing means providing a motor chamber and a gear train chamber and an intervening, partition hermetically ,preciuding communication between said chambers, said partition being provided cenin said bearing, said shafts being substantially aligned, a magnet mounted directly on the rotor shaft and being of circular outline, said magnet being transversely channeled to provide poles projecting axially within said outline and in im mediate proximity to of the partition. a keeper mountedv upon the driven shalt and provided with poles complementary to the poles of the magnet, the portion of the par- :tition thinned at said recess eomprising the only metal intervening between the poles ot the magwhich the rotor is mounted. saidl shaft project- V ingtowardsaidpartltiomaueartraininthesear 4trainehamber having a shaft projecting iran said partition in substantial alignment with said motor shaft. and malnetic lcoupling elements .mounted directly upon the respectiveshalts at opposite sides of the partition for hiah sneed magnetic motion transmigton-from Che mobr shatttotheshaftofssidleartrdmmeofsaid elements eomprisins a manet havina poles directed toward said partition and traveldnt a path not zreatly exceeding one-fourth inch in radius, the other of said elements havin! complementary poles immediately adJacent said partition, and the linear movement of the polea of the magnet element respecting the material of ofthepariitionsstoensursadrivinl between said shafts without slip and withou substantial loss of mametilm.

train wholly outside o! such water, and cui!! means providing an intervening partition between the motor memberbeinaadaptedbyreasono'titsi'ormas above donned to tend to freevitseli' from ice freezing about it. Y

FRANK W. E. WEISSE.

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