US2026297A - Viscosimeter - Google Patents

Description

Dec. 31, 1935. l J. M BELL. 2,026,297

VISCOSIMETER Filed April 21, 1934 6 Sheets-Sheet l qw xIl, Erf mmm IlIII Bec. 3L 1935,

'.l. M. BELL VISCOSIMETER Filed April 2l, 1954 6 Sheets-Shea?l 2 Dec. 3l, 1935.

J. M. BELL. 2,026,297

VISCOSIMETER Filed April 2l, 1954 6 Sheets-Sheet 5 DEC. 31, 1935. M v BELL 2,026,297

VISCOSIMETER Filed April 2l, 1934 6 Sheets-Sheet 4 Dec. 31, 1935. M, BELL 2,026,297

VI SCOSIMETER Filed April 2l, 1934 6 Sheets-Sheet 5 CoNTloL VANE .f

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QEVERJIBLE "0"" i Morob Dec. 31, 1935.

J. M. BELL` 2,026,297 VISCC-)SIMETER Filed April 2l, 1934 6 Sheets-Sheet 6 n n?, w

' CON TQOL VANE IGH `REJITBNCE RELAY HIGH 'QEfI/TBNCE 9| CONTROL VANI-2 IGH REIUTBNCE RELAY HIGH lflfTgNcE u RELAY Patented Dec. 31, 1935 UNITED STATES PATENT OFFICE VISCOSIMETER John Montgomery Bell, Chester, S. C.

Application April 21, 1934, Serial No. 721,791

8 Claims.

The object of this invention is to provide simple and reliable mechanism for indicating the viscosity of a liquid with a great degree of accuracy, this being accompished by eliminating as much 5 as is practicable the friction generated by the elements which are relied upon for measuring purposes, as more fully hereinafter set forth.

In the drawings annexed, Fig. 1 is an elevation of one side of the apparatus, some of the nonessential parts being broken away.

Fig. 2 is an elevation of another side of the apparatus, parts of the frame being in Vertical section.

Fig. 3 is a vertical central sectional view of my apparatus. v

Fig. 4 is a detail View in vertical section of the lower end of the shaft for suspending the Nviscosity-measuring-disc.

Fig. 5 is a plan view, the top motor and parts of the-frame being broken away.

Fig. 6 is a horizontal sectional view on the line 6-6 of Fig. 3.

Fig. 'l is a detail horizontal sectional View showing more particularly the circuit controlling device associated with the measuring disc, the section being taken on the line just above the springs 36. 5

Fig. 8 is a diagram of the electrical control devices all of which, except a motor 59 may be for :o convenience and protection enclosed in a box 95 mounted on the top of the frame of the machine.

Fig. 9 is a vertical section in detail of the measuring-disc suspension means.

Figs. 10 and l1 are additional diagrams of the l5 motor-control system.

lReferring to the drawings annexed by reference characters, Il! designates a tank for holding the liquid whose viscosity is to be measured and indicated, this tank being provided with an inlet L0 at II and an overflow outlet at I2 and also a clean-out device at I3. Extending up through a stuffing box in the bottom of the tank is a shaft I4 which at its upper end is provided with a driven disc I5 arranged horizontally wuthin the tank, at a point below the liquid level therein. This shaft is supported by a collar I6 and is held tight by a coil spring II arrangedbetween the stuiing box and the hub of a drive wheel I8 on the shaft I4. This shaft I4 is driven at a prei0 determined speed by any suitable.. mechanism, preferably by an electrical synchronous motor I9, the drive shaft of this motor being connected up to the wheel I8 by means of a set of worm gearing 20, a vertical shaft 2|, a belt-wheel 22 and i5 a belt 23.

eter.

The upper disc is affixed to the lower end of a tubular shaft 21 whose. upper, flanged end is attached by screws 28 to a cross-bar 29 which extends through a transverse slot in a vertical non-rotatable rod 30.

The screws 28 clamp in place a spacing ring 3l and a circuit making and breaking linger 32.

Inside the tubular shaft 2l is another rod 33 whose upper end is conically tapered to a point to form an antifriction bearing in the underside of the aforesaid bar 29. The upper end of rod 33 is aixed to the lower end of rod 3U and the lower end of the rod 33 is stepped in an upstandingpin 34 supported by a tightly tting plug 35 closing the lower end of the tubular shaft 2l.

In this way the upper, measuringdisc is suspended from the lower end of the rod 30 with the least possible frictional resistance to the oscillation of the measuring-disc and its connected parts, thereby rendering this measuringdisc extremely sensitive in its oscillations back and forth with reference to the driven disc I5.

It will be understood that while the constantspeed driving disc I5 is in rotation the liquid in the space between the two discs will tend to rotate the measuring-disc in the direction of rotation of the driven disc I5. The measuring-disc normally tends to oscillate or rotate in a direction opposite to that of the rotation of the driving-disc I5. In the present instance this normal tendency of the measuring-disc is obtained by a spring which consists of two coils 36 which have their inner ends connected by a wire or cord 3l and their outer ends hooked in holes in bars 38, these bars being affixed rigidly to a bar 39 extending through and tting tightly in the upper part of the slot in the rod 3D, at a point just above the aforedescribed bar 29.

aiixed rigidly to the underside of a plate 40, this plate 40 being provided with a hole midway its length for passage of the rod 30.

Means for aixing the bar 39 to the plate 40 consists of two screws 4I threaded into the bar 39 and o ned between the discs.

Adjacent one of the The bar 39 is 4 arcuate slots is a scale 53, which, together with a pointer li, assists in accurately setting the tension of the spring. ,In Fig. 7, the arrow within the receptacle shows the direction in which the spring tends to rotate the disc 2t. By employing two coils 3E and an intermediate exible wire 3i and arranging this wire 3l to bear upon opposite faces of a pair of spaced pins d5, the pull of the spring is so nicely balanced that practically all friction-engendering side-thrust on the bearing at the top of the shaft 33 is avoided.

It will be observed that the bar 39 moves only up and down with the rod 3@ and that its connected parts including spring Zit-3l and plate it move only with the bar 3Q; and to insure nonrotary action of the parts just referred to I providea stop-pin it mounted on the frame and arranged to extend through a slot or hole in an arm il affixed to one end of the bar 39. The disc 2S and its connected parts also move up and down with the rod 3i?, and in addition this disc 25 is permitted, as stated, a slight oscillatory movement in both directions, the extent .of this movement being determined by the two contact pins it insulatedly mounted on one end of the bar 39 and having connection through wires i9 with an electric motor hereinafter described. The finger 32 is provided at one end with an upstanding contact member 5@ which makes electrical connection with the opposing ends of the contact pins 33.

From the foregoing it will be observed that while the apparatus is in use the spring tends to rotate the measuring-disc 2S in one direction while the liquid between the discs, being given a centrifugal action by the driving disc, tends to rotate by viscous drag action the measuring-disc in the opposite direction. When the drag of the liquid is suiicient to overcome the action of the spring the measuring-disc will be oscillated or rotated in the same direction as the driving disc and contact will be made between 5G and one of the contacts d8, whereupon the electric' motor,

'hereinafter described, will be put into operation andlthrough associated mechanism, hereinafter described, raise the rod 3@ until the disc 2S is suiiiciently elevated to reduce the drag so that it nicely balances the action of the spring, where-Y by the measuring disc will again come under the iniiuence of the spring and be rotated in the opposite direction a distance far enough to at' least break contact at S-li, whereupon the mol tor will be cut out and upward movement of the measuring-disc will cease. The measuring-disc 26 and the circuit breaking nger 32 will remain l in this nicely balanced position so long as the viscosity of the liquid remains the same. Should the viscosity of the liquid decrease, the spring will again come into action and oscillate or swing the disc in the opposite direction and thus bring the other contacts -lt into action and this will serve to reverse theaction of the motor and thus lower the measuring-disc to a point where the changed viscosity will again be suiiicient to move the measuring-disc against the action of its spring and thus nicely balance the parts in their changed position. In other words, thickening of the liquid brings about an elevation of the measuring-disc while a thinning down of the liquid brings about a lowering of the disc, since the thinner the liquid the nearer the discs must be to each other to cause sumcient drag on the measuring disc to keep its controlling circuitbreaking-and-making finger 32 in a balanced position, approximately midway between the two that the centrifugal action set up by the driving disc shall not tend to create a vacuum therebetween, as that tendency would obviously destroy the accuracy of the apparatus. To keep -a constant supply of liquid to the center space 1o of the discs I not only provide the well 26 in the lower disc but I also dish upwardly the upper disc.

'I'o prevent jiggling of the finger 321 provide an oil dash-pot 5l which rigidly depends on the 15 bar 39, in position to receive a flat blade 52 affixed to the end of the nger 32 opposite its contact 5d. The rod 3G is moved up and down in a vertical bearing 53 by means of a screw 5d (formed by threading the upper end of the rod)` and a 2g nut 55 threaded on this screw and mounted within the hub of a worm-gear 56, which gear is driven by a worm 5l. The worm 5l is afxed to a shaft 58 which is driven by an electric motor 5S through the medium of a belt d, a pulley 5l, 25 a shaft 62, another belt 63 and another pulleyrr Si aflixed to the shaft 58 carrying the worm. When the motor 59 is driven in one direction the screw 56 and nut 55 will cause the rod 3@ to move upwardly whereas when driven in the other 30 direction the rod 3@ will be forced downwardly. 'Ihe motor 59 is a reversible motor and is, as stated heretofore, rotated in one direction or the other according to which of the contacts 5&-56

A scale is provided on the 35 l are in engagement. periphery of the worm-gear 56, which together with an associated pointer 65, indicates the position of the measuring-disc and therefore the viscosity of the liquid. If a further indication of the viscosity is needed I employ an additional ino dicating wheel 66 provided with a scale on its periphery associated with pointer Si, and I operate this additional indicating wheel by' means of a pinion 63 aiiixed to its shaft and a rack 69 afxed to a rod Iii, this rod being'reciprocally 45 supported in the frame and being resiliently i pressed down on the upper end of the slidable rod 3d. In this way the vertical movements of the rod Sii will be indicated on the scale on wheel In some cases it is desirable to utilize a scale 50 on the worm gear for indicating fractions of units of measurement and a scale on the wheel 66 for indicating whole units. 'I'he structure obviously lends itself nicely to this division of the 55 indicating means since even an entire revolution spring 73 coiled around the shaft of the scale wheel 66. It is desirable that the liquid in the tank i@ be kept stirred in order to avoid cakng and I therefore provide two vertical stirrers lf3 depending into the tank and provided with stirring blades l5, these stirrers being rotated by pulleys It attached to the upper ends of their 70 shafts and driven by a belt il, which in turn is driven by a pulley 'I8 aflixed to a vertical shaft I9 which is power-driven by a belt 80 running 'v over pulleys @i and 82 axed respectively to the aforesaid shaft 'I9 and the aforesaid shaft 2i of 75 the main motor I9. An idle pulley 83 is associated with the two pulleys 16 in order to drive the stirrers in opposite direction.

In Fig. 8 I show a preferred electrical arrangement for controlling the reversible motor 59 from the swinging contact member 32. The hereinbefore mentioned conductors 49 form the primary circuits of two transformers 84, and connected to this primary circuit 49 and the contact finger 32 are the respective terminals of the secondary circuit 85 of a spark coil 86 having the usual vibrator and any suitable source for energizing it, a battery 81 being shown. The secondary circuit 88 of each transformer has its terminals connected respectively with the grid and the negative side of the filament of a well known audion tube 89, so that when a potential is impressed upon either of the secondary circuits 88 the electronic flow through the tube will be either wholly stopped or sunciently interrupted to arrest the circulation of current through a relay circuit 90 which includes a relay 9| and the lament and the plate of the tube. When no current is flowing through either one of the relays 9i its armature 92 is released and then current is flowing through fields and armature of the motor 59 in one direction. In Fig. 8 the armatures are both in closed position and both field circuits 93 of the motor are cut out, and the controlling contact finger 32 is in neutral position, but when the contact finger 32 is moved in either direction far enough to close the primary circuit of its associated transformer, the associated relay 9| Will be de-energized and thus release its armature 92 to thereby close its associated eld and armature circuits and cause the motor 59 to run. The direction of running of the motor will of course be determined by which one of the contact pins 48 is brought into action.

It Will be understood that Fig. 8 shows the armatures of both relays 9| energized and that in that condition no current will be on the motor, and the same result would follow if both relays are de-energized. The direction in which this type of motor runs is determined by the relative polarity of the eld and armature; reverse either and the motor will run in the opposite direction. In the drawing the field windings are terminated on 110 volt A. C. leads. The motor circuit can be closed only when relay armatures are in opposite positions. In Fig. 8 both relays are energized by the passage of plate current through the tubes 89. Maximum plate current is flowing and will continue as long as the grid has a negative polarity. As soon as a positive potential is impressed on the grid through the transformer secondary 88 the plate current is greatly reduced or ceases altogether, thereby allowing the corresponding relay armature to fall or spring back and thus cause the motorto run in the proper direction.

All the foregoing electrical devices except the motor 59 are desirably enclosed in a box or case 95 mounted on the frame of the machine.

The whole purpose of the electrical control shown in Fig. 8 is to avoid the necessity of having the contact finger 32 make forcible, actual contact with the contacts 48, as such forcible or pressure contacts would to an extent interfere with the delicacy of oscillations of the measuring-disc. Actual contact between 32 and 48 is avoided by the use of this spark coil which when these contacts approach each other will cause an arc or spark to form before the contacts come together and thus avoid the necessity of physical pressure at the contacts. Ordinarily arcing at these contacts would be undesirable but in view of the need for delicately mounting the measuring-disc the arcing at least at the contacts is highly desirable as it insures prompt and sure actuation of the motor even though the contacts be oxidized or dirty. By thus providing for arcing at the contacts I of course do away entirely with the necessity of making actual positive contacts but of course in the operation of the apparatus the movement of the finger 32 cannot in most instances be arrested quickly enough to prevent actual contact. My arrangement, however, does avoid all necessity of any considerable pressure of one contact against the other and that is the Whole purpose of employing the spark coil. In the drawings the contact-pins 48 are illustrated as being set farther apart than. is necessary for measuring the general run of liquids; in actual 2o practice I have found it to be desirable to set these contacts quite close together, even less than a quarter of an inch, and the closer together the contacts are set the more accurate Will be the measurement of the viscosity.

The opposed contacts 48 may be rendered adjustable toward and from each other by any suitable means; I have shown set-screws 96 for this purpose. The adjusting of these contacts toward and from each other to vary the space in which the contact 50 vibrates is important in that it enables me to adapt my device for nicety of measurement. The closer these contacts are set to each other, the nicer will be the degree of measurement of viscosity as is obvious. With regard to the two upstanding pins 45 it will be observed that these pins are located at opposite sides of the center of rotation of the shaft of the measuring-disc and that the connecting cord 31 is so arranged as to exert as nearly as possible an equal pull on opposite sides of the pins; this is important in that it avoids any tendency to tilt the shaft of the disc and thus eliminates friction in the suspension bearing to as high a degree as possible.

I desire it to be understood that while the electric sensitive control system diagrammed in Fig. 8 is particularly desirous in connection with my viscosimeter apparatus, 'I believe that the principle therein is capable of use in other connections and I therefore do not limit my claim solely for use in connection with viscosimeters.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiments thereof, but I desire to have it understood that the apparatus disclosed is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combinations and relations described, some of these may be altered and others omitted and some of the features of each modification may be .embodied in the others without interfering with the more general results outlined, and the invention extends to such use.

I claim:

1. In a visccsimeter, the combination of a tank, a driving-disc therein and means for ro- 70 tating it at a constant speed, a companion measuring-disc, means for supporting said measuring disk face-to-face with respect to said drivingdisc in such manner as to have a limited rotary movement in either direction, devices normally tending to rotate the measuring-disc in a direction opposite to the direction of movement of the driving-disc, whereby drag of the liquid between the discs tends to rotate the measuringdisc against its normal tendency, and powerdriven reversible actuating mechanism for moving the measuring-disc toward and away from the driving disc, and means for putting said power-driven actuating mechanism-into operation to move the measuring-disc away from the other disc when the drag overcomes its normal tendency to rotate and to move the measuringdisc toward the other disc when the drag is insumcient to overcome said normal tendency and viscosity-indicating-means actuated from said power-driven reversible actuating mechanism.

2. The structure recited in claim l, said actuating mechanism embodying a reversible electric motor, circuits including a pair of opposed contacts, and a contact member attached to the measuring-disc whereby when the measuringdisc is rotated in one direction it will close one circuit and cause the motor to run in one direction, and when the measuring disc is rotated in the opposite direction it will close the other circuit and thus cause an opposite rotation of the motor.

3; The structure recited in claim 1, said actuating mechanism embodying a vertically movable rod on which is rotarily suspended the measuring-disc.

4. The structure recited in claim 1 said actuating mechanism embodying a reversible electric motor having two circuits, means actuated by the measuring-disc for closing one or the other of said circuits according to whether the measuring-disc is rotated by the drag of the liquid or by its actuating devices, for the purpose set forth.

5. The structure recited in claim 1, a reversible electric motor being embodied in the actuating mechanism, means actuated from the rotary movements of the measuring disc for closing the circuits of this motor, to thus raise or lower the measuring-disc by power.

6. The structure recited in claim 1, the devices normally tending to rotate the measuring-disc embodying a pair of pins mounted at opposite sides of the center of rotation, and a tensioned spring arranged to pull in opposite directions on the opposite sides of said pins to thereby eliminate tendency to tilt the measuring disc axis, whereby friction is reduced to a 7. The structure recited in claim l, the devices normally tending to rotate the measuringdisc embodying a pair of pins mounted at opposite sides of the center of rotation, and a tensioned spring arranged to pull in opposite directions on the opposite sides of said pins to thereby eliminate tendency to tilt the measuring disc axis, whereby friction is reduced to a minimum, and means for varying the tension of said spring.

8. The structure recited in claim 1, said reversible actuating mechanism embodying a reversible electric motor, said means for putting said actuating mechanism into operation em `bodying a movable contact inger, a pair of opposed contacts cooperating therewith, and electric means for producing an arc when said contact nger approaches either one of said contacts to thereby render actual physical contact unnecessary.

JOHN MONTGOMERY Bm.

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