US2074174A

US2074174A - Viscosimeter

Info

Publication number: US2074174A
Application number: US81638A
Authority: US
Inventors: Goodier James Norman
Original assignee: Ortech Corp
Current assignee: Ortech Corp
Priority date: 1936-05-25
Filing date: 1936-05-25
Publication date: 1937-03-16
Anticipated expiration: 1954-03-16

Description

Patented Mar. 16, 1937 UNITED STATES PATENT OFFICE VISCOSIMETER. A

I Application May 25, 1936, Serial No. 81,638

9 Claims.

' This invention relates to viscoslmeters of the type in which samples of a liquid whose viscosity is to be tested are introduced into a narrow space between two relatively movable surfaces, the resistance to rotation under similar conditions serving as a measure of the viscosity of any given film, .and my object is to provide apparatus of this type which will enable an operator to quickly. test successive samples of liquid at a standard temperature without requiring the taking of exactly measured samples. I attain my object by means of a construction which may be briefly described as follows:

The basis of the device comprises .an imperl5 forate bowl shaped member and a second imperforate member concentric withand normally'positioned within the bowl with its external surface slightly spaced from the internal surface of the latter to form a space to contain a thin film of the liquid to be tested. While the width of this space may vary I find fifteen one-thousandths of an inch is satisfactory for one type of patent leather varnish.

The two members are relatively rotatable and for convenience may be referred to as the stator and rotor. The bowl will ordinarily be the 'stator and the other member the rotor. The rotor and stator are movable axially relative to one another to facilitate the introduction of liquid into the stator. -The stator is waterjacketed for cooling purposes.

The invention is hereinaftermore specifically described and is illustrated in the accompany 7 ing drawing in which Fig. 1 is a vertical section of the device; and

Fig. 2 a plan view of the same with the driving pulley omitted.

In the drawing like numerals of reference indicate corresponding parts in the different 11g l The device comprises two main parts abowl shaped member and a second member concentric therewith between which is disposed a thin fllm oi' the liquid to be tested. One of these parts is a rotor and the other a stator. Pref erably the bowl shaped member I is the stator and the member H the rotor. By bowl shaped is to be understood that the interior of the stator is of such a shape that when the rotor, which has a corresponding exterior shape, is moved axially relative to the stator the distance between the surfaces is varied and thus the thickness of any liquid contained between the two. In. e preferred form both surfaces are suhstan y conical. The stator is formed on or connected with the base 2. The upper edge or rim of the stator extends laterally and terminates in the annular trough 4.

The base 2 is provided with the bearing support 6, which is formed with a bridge carrying the bearing 1. 'The bearing support 6 is formed with the depending annular flange-8 which fits closely within the rim 5 of the base 2 to thus position the support 6 relative to the base 2 and therefore to the stator. lifting screws 9 are 10 threaded through the bearing support 6 andbe'ar upon the upper surface of the rim 5. These serve as a means for backing off the bearing support 6 in case it becomes stuck or gummecl up with the liquid being tested. 1

In the bridge of the bearing support the bearing l is centrally positioned in axial alinement with the stator and through the bearing the spindle It! extends so as to be rotatable in and slidable lengthwise of the bearing. To the 0 spindle is securedthe rotor II which in its lower part is concentric with the stator and is formed with an upwardly extending rim l2 extending well above the rim of the bowl of the stator.

Set in a recess 1 nthe lower end .of the rotor 25 in alinement with the axis thereof is a ball 13 forming a thrust bearing, which ball is adapted to run in a recess formed in the upper end of the block I which is preferably threaded into the apex of the bowl to form a bearing for. the 30 ball l3. The block is thus readily renewed in case of wear. It may be also used to adjust the space left between the adjacent surfaces of the rotor and stator as may be required. Usually the ball and bearing will be so positioned rela- 35 tive to one another that a space of about fifteen one-thousandths of an inch is left between the adjacent surfaces of the rotor and stator.

The base 2 of the stator is hollow so that it forms a water jacket for the exterior of the 40 stator. Within the hollow base is fitted the cylindrical balile I5, from the upper rim of which depends the frusto-eonical bafile It. A water inlet I! is provided leading into the space outside the cylindrical baflie while the outlet 18 45 communicates with the space within the cylindrical bame. Ice water entering through the inlet I1 is thus compelled to pass in a stream over the outer surfaces of the stator, thus efficiently cooling the same.

To the upper end of the spindle I0 is secured a pulley l9, around which is wrapped a cable 2| which passes over the sheave 20 carried by any suitable support and has a weight 22 secured to its end. The weight thus serves to rotate the rotor H.

- The operation of the device is substantially as follows:Cooling liquid, usually ice water, is kept continually circulating through the base so that the bowl of the stator is maintained at a temperature very close to the freezing point. The rotor and bearing support are then removed from their position on the base and a quantity of the hot liquid to be tested is poured into the bowl l. The actual quantity poured in needs tube a little more than enough to fill the gap between the stator and the rotor when the latter is in position and a suitable quantity is easily estimated by eye or otherwise approximately measured. The bearing support is then replaced and the rotor and spindle pushed downward through the bearing until further descent is prevented by the ball l3 taking up its position on the block I l. During this descent, which occupies only a few seconds of time the fluid in the bowl is forced to form a thin film occupying the space between the rotor and stator and completely filling it,'excessive fluid overflowing into the trough Q. The rotor is then driven by means of the cord and weight and the time occupied by one or more revolutions measured. This time is the measure of the viscosity of the fluid. The rotor assembly and bearing support are removed, the rotor and bowl of the stator wiped clean, whereupon the instrument is ready for a repetition of the operation on a new sample.

Each repetition of the operation; that is, pouring in the sample, assembling the instrument,

timing the rotation, dismantling the instrument and cleaning it occupies some two to three minutes.

It is found in practice that the fluid is cooled from temperatures as high as 550 F. to freezing point in the short time required to assemble the instrument. The instrument is thus of special value when the progress as regard to viscosity of a heated fluid, occurring in a processingvessel, is to be followed up to a desired final state which is indicated by the attainment of a. certain viscosity. This instrument thus makes it possible to control the preparation of fluids, such as varnishes, which are so thin at the processing temperature that they offer little real resistance to the motion of the rotor but which have a very considerable viscosity at 32 F.

The cooling of the rotor by filling its interior with ice water may be resorted to as a supplement to the cooling of the stator.

What I claim as my invention is:

1. A viscosimeter comprising an imperforate bowl-shaped member having an open top; a second imperforate member concentric with and, complementing the first and normally positioned within the bowl with its outer surface slightly spaced from the inner surface of the bowl, the said members being axially displaceable relative to one another so that liquid placed in the bowl when the said members are separated is squeezed into a thin film between the members when the latter are restored to their normal co-operative position.

2. A viscosimeter according to claim 1 in which the bowl-shaped member is formed with its upper margin below the level of the top of the other member when the two are in co-operative position to provide an overflow for surplus liquid.

3. A viscosimeter comprising an imperforate bowl-shaped stator; a base carrying said stator; a bearing supported from the said base in axial alinement with the stator; a spindle journaled in and slidable through the bearing; an imperforate rotor concentric with the stator and secured to the spindle; and a thrust bearing between the rotor and stator defining the axial position of the rotor relative to the stator.

4. A viscosimeter comprising an imperforate bowl-shaped stator; a water jacket surrounding the stator; baffles in the water jacket to direct flow over the outer surface of the stator; an imperforate rotor concentric with the stator and mounted thereon to slide axially thereof; and a thrust bearing between the rotor and stator defining the axial position of the rotor relative to the stator.

5. A viscosimeter comprising an imperforate bowl-shaped stator; an imperforate rotor concentric with the stator and mounted thereon to slide axially thereof; and a thrust bearing between the rotor and stator defining the axial position of the rotor relative to the stator, the rim of the bowl being positioned below the top of the rotor when the rotor and stator are in co-operative position to provide an overflow for surplus liquid.

6. A viscosimeter comprising an imperforate bowl-shaped stator; an imperforate rotor concentric with the stator and mounted thereon to slide axially thereof; a thrust bearing between the rotor and stator defining the axial position of the rotor relative to the stator; the rim of the bowl being positioned below the top of the rotor when the rotor and stator are in co-operative position; and an annular trough to which said rim discharges.

7. A viscosimeter comprising an imperforate bowl member having a substantially conical inside surface and an open top; a second imperforate member having a substantially conical outer surface similar to that of the inside of the bowl, the said members being relatively rotatable and also axially displaceable to vary the spacing of the aforesaid surfaces; and adjustable means for setting the minimum spacing.

8. -A viscosimeter according to claim 1 in which the bowl-shaped member is formed with its upper margin below the level of the top of the other member when the two are in co-operative position to provide an overflow for surplus liquid; and a water jacket is formed about the exterior surface of the bowl-shaped member.

9. A viscosimeter comprising an imperforate bowl-shaped stator member; an imperforate rotor member concentric with and complementing the stator member and normally positioned within the stator with its outer surface slightly spaced from the interior surface of the said stator; a base carrying the stator; a bearing supported from said base; a spindle journalled in and slidable through said bearing and to which the rotor member is secured, the said rotor member being therefore axially displaceable relative to the stator JAMES N. GOODIER.