US2668441A

US2668441A - Viscosimeter

Info

Publication number: US2668441A
Application number: US96641A
Authority: US
Inventors: Wesley M Peterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-06-02
Filing date: 1949-06-02
Publication date: 1954-02-09
Anticipated expiration: 1971-02-09

Description

Feb. 9, 1954 w, PETERSON 2,668,441

VISCOSIMETER Filed June 2, 1949 IN VEN TOR. W. M. PETERSON ATTORNEY Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE 2 Claims.

The present invention relates to improvements in viscosimeters and has reference to improvements for increasing the accuracy of measurement rather than any improvement in the fundamental viscosimeter characteristics.

- Various viscosimeters which have been in wide useage are based upon the use of a stopper inserted in an opening below the orifice of the instrument. This has lead to large errors, particularly with low viscosity fluids, since some of the fluids will frequently pass through the orifice into the chamber between the orifice and the stopper. When the stopper is pulled, this portion of the fluid will pass into the measuring receiver without passing through the orifice during the measured time. Furthermore, timing of the pulling of such a stopper leads, likewise, to major errors.

Among the objects of th present invention are the provision of improved viscosimeters; the provision of viscosimeters having means for initiating flow through the orifice with exactitude, the provision of viscosimeters in combination with time-registering means, and such further objects, advantages, and capabilities as will hereafter appear and as are inherent in the construction disclosed herein. My invention further resides in the combination, construction, and. arrangement of parts illustrated in the accompanying drawings and, while I have shown therein what is now regarded as the preferred embodiment of this invention, I desire the same to be understood as illustrative only and not to be interpreted in a limiting sense.

In the drawings annexed hereto and forming a part hereof,

Fig. 1 is a schematic diagram, partially in vertical section;

Fig. 2 is a plan of the viscosimeter; and

Fig. 3 represents a section taken substantially along the plane indicated by the line 3-3, Fig. 1.

viscosimeters in accordance herewith are provided with an orifice closure at the upper end of the orifice within the reservoir. Common operating means are provided both to initiate flow through the orifice by lifting the closure and to start a time register.

The viscosimeter hereof includes a viscosimeter tube 4 which has a conical lower inner surface. Centrally of the lower end, the tube 4 carries a press fit insert 5 which has an opening 5 therethrough of calibrated size. Plugs of the same sizes but having openings of different sizes may be provided for use with fluids of different viscosities. The tube 4, further, is provided with a hollow boss 1 which extends through and is secured in a wall of a temperature-controlling jacket 8. The tube 4 is provided, at a level just below its open upper end 9, with an outwardly projecting flange l0 which has a circular wall I l rising therefrom. The flange l0 and Wall ll form an overflow container to receive excess fluid placed in the tube 4. The circular wall H fits into a circular opening in the upper wall of the jacket 8, to maintain the tube 4 in alignment.

A circular plate I2 rests on and fits within the upper edge of the wall H, being provided with openings I-4 through which to insert a stirrer and thermometer into the tube 4, and with an opening [5 in alignment with the overflow container about the tube 4. By means of the opening l5,a syringe or pipette may be inserted into the overflow container to remove excess liquid and ensure that the operating head of the viscosimeter is exactly at the upper end of the tube 4. Having the top of the fluid at the edge 9 of the tube 4 ensures that the initial hydrostatic height of the liquid above the orifice 6, at the time of starting the fluid flow, is always constant.

.An operator is mounted on the plate l2 to initiate flow from the viscosimeter. A typical example of such an operator is constituted by a pair of mounting posts It of brass or other magneticallynon-responsive material. A pair of solenoids I! are mounted upon posts 46. The solenoids I! are provided with conventional soft iron core l8, which ar in magnetic contact at their upper and lower ends with magnetizable plates [9 and 20 which interconnect the solenoid cores l8. Between the solenoids ll, a nonmagnetic tube 2| is secured in plates [9 and 20, with its lower end open and its upper end closed by an extension from the upper magnetizable pole piece. Whereas most tandem mounted solenoids are wound in opposite sense, whereby lines of flux flow successively through the two, it should be understood that the present tandem mounting is not of this sort. In this typical example, the direction of winding of the coils is such that the polarity of the corresponding coil ends is the same. With this arrangement, the plunger 24 forms a bridge common to the two coils. The solenoids are suitably wound and connected'in the sense stated and provided with

conventional contacts

22, 23. This construction may be replaced by a single solenoid suitably constructed and placed. The electromagnet is of such a nature that the residual magnetism described above retains the valve in open posi-,

tion thereby obviating the necessity of keeping th key depressed during the flow of fluid.

A plunger 24 is provided for sliding within the tube 2|. This plunger 24 is of a steel such that it is a semipermanent magnet. Thus, when the electromagnet is energized, the plunger 24 moves into contact with a downward extension from the central part of the upper pole piece 20. The residual magnetism of the plunger 24 will maintain the plunger in actuated or raised position. While the plunger 24 has been described as a semipermanent magnet and the remainder of the metal in the magnetic circuit as soft or nonpermanent iron, all that is necessary is that some portion of the metal in the circuit be at least semipermanent. Thus, the plunger maybe of soft iron and either plate I9-or or one or both of the solenoid cores lfl'may be of magnetic or semipermanent magnetic material.

The solenoid is so mounted that the plunger 24 is positioned axially of the tube 4. A valve rod 25 is secured in the lower end of the plunger 24. A valve 28 is secured to the lower end of the rod 25. The lower surface of valve 26 is shaped to contact the lower inner wall of the tube 4, which may be of any suitable shape, whereby, when the plunger 24, rod 25, and valve 26 assembly is in lowered position, the valve will seat accurately and close the opening 6 tothe passage of fluid.

If desired, a hanging eye 2'! may be secured to the-pole piece 20 wherewith to suspend the viscosimeter structure, just described.

A starter and timer is shown in the lower left portion of Fig. 1. This consists of a lever mounted on a pivot 28 in a cabinet 29. One arm 30 of the lever extends horizontally within the cabinet. A springtl, in engagement with the lever, moves the arm 38 upwardly into normal position of the spring. A key 32 is connected'to the free end of the arm 38 for moving the arm downwardly upon depression of the key. A switch contact 33 is secured to the free end of the arm 38 and is in electrical contact with the circuit line 3%. A second switch contact 35 is mounted in the cabinet and is in electrical contact with a circuit line 38. Upon depressing the key 32,

contacts

33 and 35 engage to close the switch.

The lever in the cabinet 29 is provided with a second arm 31 which extends upwardly out of the cabinet. Movement of the key 32 brings-the lever arm 31 into operative engagement with a time register, such as a stop watch 38 to effect starting and stopping of the register upon successive depressions of the key. Any suitable time register, electrical or mechanical, may be employed which can be started or stopped by successive operation of the key. In order to be able to produce substantially simultaneous op eration of the switch and the starting of the timer, the crank arm 51, shown in Fig. 1, may have an adjustable pin for actuating the timer stem, as shown, or one of the

electrodes

33, 35 may be made adjustable.

Circuit lines 3 3 and 36 are connected

wit contacts

23 and 22, and with a battery 39, or other source of direct current in the circuit.

In operation, a cork is first put into the opening in the bottom of the tube d, with the operator removed, and then the fluid to be tested is poured into the tube until it reaches a height above the tube 4. During filling of the tube 4,1

the corkis kept in the hollow boss I, but it is not employed to start the flow of fluid through the orifice.

After the tube 4 has been filled and the valve member 26 and its operating structure have been put in place, the temperature of the fluid is brought to any desired degree by means of the controlled bath temperature. A suitable thermometer and a stirring disk are inserted in an opening l4. When the temperature is correct in the tube 4, the thermometer and stirring disk are removed. Then the cork 40 is removed and a standard receiver is placed close to the discharge opening. Next, the excess fluid around the upper end 9 of the tube 4 is removed by a pipette or other suitable instrument. They key 32 is then tapped and this starts the timer 38 and momentarily closes the

switch

33, 35 so as to cause the valve member 26 to rise to its fixed upper limit of motion, thus starting the flow of fluid through the orifice at zero time on the timer"38-. When the fluid height in the receiver reaches the hairline, the key is tapped again and this stops the running .of the :timer. It also sends an impulse through the coils H, but this second impulse through'the coils is oi'no consaquence. The tapping motion given to thekey, as described, is of significance in affording a; convenience of manipulation at the start of the timing and at theend thereof, and in reducingpersonal error in timing the transit ofthehairline at the end of the test. The receivers in common use have a sufficient capacity to-hold all of the fluid in the tube 4.

It is of course understood that the specific description of structure set forth above may be departed from without departing from the spirit of this invention as described in this specification and as defined in the appended claims.

Having now described my invention, 1 claim:

1. A viscosimeter comprising a vertical container for liquid to be tested, there being an orifice in the lower end thereof, a circular plate in the form of a ring-like part connected to the peripheral portion of the upper end of said con-- tainer and having a pair of mounting'postscar ried by said plate, a pair of solenoids mounted in laterally spaced relation on the upper ends of said posts, elongated upper and lower pole pieces, the lower pole piece crossing'theopening in said ring-likepart, leaving two'openings ateach side of the lowerpole piece, the spacing between said solenoids being sufficient to have the solenoids clear said two openings, whereby the latter are accessible from points substantially directly above, thereby readily accommodating in said container, a valve controlling said orifice,

an electrical solenoid controlling said valve, 2.

stop watch support, a stop watch mounted on said support, a bell crank pivoted thereon and including an arm for controlling said watch, a

second arm on said bell crank, contact means carried by said-second arm, a spring connected with said second arm for moving the latter in.

a direction to open said contact means, a manually actuable part connected with said second arm for moving the latter against the action of said spring to momentarily close said contacts,

and circuit means connected between said contact means and said solenoid, whereby said solenoid is operated substantially simultaneously with the starting and stopping of the watch, said solenoid being so constructed and arranged that the residual magnetism is suflicient to hold said valve open, said watch being stopped by a second actuation of said manually actuable part.

WESLEY M. PETERSON.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Courtois Apr. 25, 1905 Number Number 6 Name Date Kahrs May 20, 1913 Saybolt Mar. 23, 1915 Teschner May 20, 1931 Fairbairn June 14, 1932 Thomas Aug. 24, 1937 Fairbairn Mar. 14, 1939 Von Stoeser et al. July 31, 194 MacDonald Apr. 29, 1950