SU37382A1 - Instrument for determining the viscosity of liquids (viscometer) - Google Patents

Description

The most common method for determining the viscosity of liquids is to use a method based on the law ист expiration of a viscous liquid from capillaries: fe i; .v, i--. tubes (Poisail method). 1о;: Poiseuille volume v of flowing G | - :) K: id (spines from the capillary length / and radius; mustache G - at pressure / for time 1 is given by the formula v-ъ f. :---. I SC : -: and - /;. where 7) is the viscosity of the outgoing fluid. CH.GESLI All quantities in the form of žnlu (1), expressed in units of biQQS systems, should be expressed viscosity | SW; pauses. , - | ,; Gpcp: the lightest viscometer is -p; myself a vessel,. in whose bottom ||; a pipe for the flow of fluids; bones. Opening the tube hole, for; Let the test fluid flow out. As it elapses, its horizon in the vessel decreases; pouring liquid with a pipette or otherwise, keep the horizon unchanged so that the constant pressure Pi is saved, and f |; J note the expiration time t of a certain volume of liquid v. Progress- :; ". . -.- -and--. , .-,: ffii- e «,; -5 W: d; w- :.h ..- .. t in the vessel unchanged, and record the time ti expiration of the same volume of its g. Using formula (1) dp the expiration of both the test liquid and water: : i $ find the desired viscosity TJ. .i 1 ".} 4 where rji is the viscosity of water at the temperature of the experiment, which is from the tables. If water is poured into a vessel to the same level as the liquid being tested, then the ratio of the pressures — in formula (2) can be replaced by the ratio of their specificity: –8 — the weights –jT and formula (2) accepts -. : v; -; view :: g. - (3) where 8i is the specific gravity of the test liquid, and §2 is the specific gravity of water at its expiration temperature. Calculation t) ,. from formula (3) is associated with a known loss of time, the production of experience itself is also somewhat difficult, since it is necessary to simultaneously monitor the filling of the volumetric flask to which the liquid flows, after the stopwatch and continuously

keep the outflow fluid horizon unchanged.

Engler's viscometers (USSR, Germany and Scandinavian countries), Redwood (Great Britain) and Saybolt (US) are more often used in technology. With the help of these devices, the expiration time of a certain volume of the test liquid is determined. The expiration time, expressed in seconds, gives the corresponding number of Engler, Saybolt or Redwood seconds, which characterizes the viscosity of the fluid. However, it should be borne in mind that all such conventional viscosity units actually do not accurately characterize the viscosity of the liquids being tested, since the outflow from these devices occurs at varying pressure (the horizon of the liquid in the outflow vessel is not kept constant). In addition, the specific gravity of the liquid in the formula (3) is not included in the calculation at all. It is easy to see that two liquids having a fractional density, but the same viscosity, will expire from a viscometer for different times and will be characterized by a different number of seconds of viscosity. Finally, the volume of the outflowing fluid is measured in viscometers with the aid of dimensional Aolb; than, during the outflow, the liquid is usually cooled to room temperature, and the volume ee, v in the volumetric flask is not equal to the volume of the outflowing liquid, 213 outflow vessels;: it often happens at a different temperature (usually at 50 ° or higher). Thus, oil, at a rate of 20 ° C, in a dimensional band 200 sls, occupied in co (at 50 ° a volume of about 206 ate, at 100 ° –214 a and at 200 ° –234 ate. However, despite the above disadvantages of viscometers and some other shortcomings in their work, they are ubiquitous, because the viscosity determination of the ave.

The author proposes to use the viscometer of his system, which allows all work on the determination of viscosity to be performed automatically.

Nl drawing; e fig. 1 shows a general view of the device; FIG. 2-appearance of the float with a frame and a volumetric flask; FIG. 3 shows a dial for counting the result of the determination; FIG. 4-view gears with a dog; FIG. 5 is a modification of a device for maintaining the level of a liquid in an outflow vessel.

For the determination, pour the test liquid into a vessel of a predetermined level and turn on the current. Further work is performed entirely by the device itself, which does not require any observation of oneself or even presence in the room where it is located. The instrument itself automatically maintains a constant liquid horizon in the outflow vessel.

At the moment of filling the measuring cone, the further outflow of fluid is stopped, and the bell rings, announcing the end of the experiment. It is only necessary to read the readings of the instrument, which on the dial shows the viscosity of the liquid directly; -: at the centipoise, and turn off

Stoke .-;,., - /: - -.: L, -1. . -. , h; ; Thus, the use of the device allows to mechanize the whole process.

by; defined (rotting viscosity and requires minimal. time consuming. Except

trgb; / the result is obtained with ds of exactness expressed directly in / cents, and not in conventional units of viscosity, which is also extremely important.

W-loss of time usually

in Engler viscometers, applied in the USSR; heating is tested; my life is 1; temperature is at the required temperature; which is produced. definition of its viscosity. The device proposed by the author is supplied with an automatic thermostat, thus this process will not require any additional loss of time.

Taking into account the enormous importance that the definition of viscosity has in determining the suitability of lubricating oils and liquid fuels, and when evaluating petroleum products, the author believes that his device may be of some interest.

 The operation of the device is based on the application of the above formula (3).

CL:: r; ; SSii.;:,,

 The values, 2 and oz are constant. Indeed, the viscosity of water TI and its specific gravity, this temperature, are from the tables. The expiration time of its specific volume v at a certain constant pressure for a given device (at a temperature for which its viscosity and specific gravity is taken from the tables) is also a well-defined value. Thus, formula (3) takes the form: TG / a; Oj 1 where k- (constant for this device value, which we will in the future be called a constant viscometer). If at the moment the test liquid starts to flow, an electric current is applied that triggers the electric clock, the arrow of this watch, moving across the dial, will indicate the duration of the expiration. If at the moment of filling a certain volume V (of course, the same as the volume of water that has leaked out in time 2) to turn off the current, the arrow will stop and indicate the time of expiration of this liquid, i.e. ti.-: To determine the viscosity TJ by the formula (4), it will be sufficient to multiply the time ti by the specific gravity of the Si fluid and by the constant viscometer, However, the work can be greatly simplified if the finished work is applied to the dial of the electric clock, then the arrow will give the viscosity of the test fluid expressed in poises (or centipuza x). Since the instrument must be used to determine the viscosities of liquids with different specific weights, the dial should have not one but a number of scales in the form of concentric circles divided by centipases for liquids with different specific weights. In FIG. 3 depicts a view of such a dial.

. An electric clock can be equipped with a second small hand, counting the number of full turns of the large hand. When testing conventional lubricants with viscosity with a viscosity of approximately less than Yu Engler, make a readout: i only by the indication of a large arrow for very viscous liquids, eg -; measures glycerin, castor oil, etc, d.:. :. the expiration of which at low temperatures; ;: 4 rounds, the edge is slow, the .OTrg, is, the score is made on the readings of both. shooter ..; :;: L -; - - .: -: ovS; S The device consists (Fig. -1 of the drawing) ;; : from thermostat /, set. on-four; Greh legs. Water is heated to this thermostat, which is heated: Up to; required | Mud: temperature. If necessary npJFiyMrtTfcfc; temperature above 1 (X) thermostat can be replaced with water by oil; ILN ;; 1И1ЯО with any liquid with sufficient boiling point. Description of elecgra | 0 heater with thermo | egorul toromi – gi jriu / A .-- -.- -f - iittil- i.i. - -.-:,.: .. ---. ,,, "In the thermostat / places:;,;. Cut, Schuvar 2 (outflow vessel), -: 1c; Shbts; It is SPECIFIED by the test subject: zhidkost 1; N | r the walls of the tank are. hook; J1SCH || to set the level of the liquid. Airborne;. In her part of the reservoir there is a drip: ;; on the outflow tube 4, otverg itgo ||; the swarm is closed by a pin 5;: - sV ;. Fallen n 6njria is immersed in the tank; | i | fe; wok b (for example, from aluminum); ssdilin | drilled hole along the axis,.; which passes the pin S- .. To the float b rigidly INPIS rep | en: -. frame 7.8, 8.7, at the bottom of the Kotor Sh -. a volumetric flask is set up — this bulge comes against a single day; tube expiration 4. The appearance of the float with a frame volumetric flask is shown in FIG. 2 black-, tezh. As you can see, the frame consists of sin. racks 7, 7, 7, connected below part. mi 8, 8, 8. Balls W, JO, / O, moved along the rods 7 /, / 7, 77 with screw thread, are used to eliminate distortion of the instrument. -:; The frame is equipped with a pin 72, the arrival - J, schims over a cup 75c mercury. The pin 5 is pivotally connected to the shoulder 7 of the lever J4,75 fixed at point 76 on the board. Tick vessel% 7. Arm 75 lever i is equipped with a bark 77. Arm J4 ogg yy-t-- .--. f --- - -, r.

It is possible that the pitamps of the first and second circuits from the battery are powered by the same current from the mains as used for the third and fourth circuits. In addition, it is recommended in the thermostat / (or the outflow vessel) to place the mixer in the form of a small screw with paddles for mixing the liquid when heated. To rotate the agitator, place a small electric motor powered by current from a third circuit. The motor will work intermittently, and from time to time the fluid in the thermostat will mix.

The subject matter of the invention.

1. An instrument for determining the viscosity of liquids at the rate of their outflow, consisting of an outflow vessel, fitted at the bottom with a pin-out tube for outflow, characterized by

the use of a body 6 located in the vessel for expiration, intended to maintain the test liquid at the same level during the expiration, which body 6 is connected by means of grades 7-8 with a flask 9 receiving fluid flowing ..

2. The use of an electric clock with several concentrically arranged scales on the dial for the viscosity of liquids with different specific weights, which are connected by conductors of electric current, connected, in turn, by a pin / 2, tons of 7-8 and cups / 3 with mercury with body 6.

3.Application with the aforesaid pa ;; 1 and 2 of the viscometer of electric heating elements equipped with thermo: regulator 25-26 and located in the vessel: e /, surrounding the vessel and ischeche; “neither 2 ..,: