SU1136063A2 - Float-type liquid density meter - Google Patents

Abstract

PSYAPAVKOVSH SJTNOSH LIQUID on auth. 9 765705, characterized in that, with whole improvements in measurement accuracy, the axis of the profiled element, passing through the medium-sized radii of the involutes, is positioned relative to the α-vertical axis of the float at an angle of 15-30 °. axis perpendicular to first. 5: oh oh ed: o

Description

I11

The invention relates to the field of investigation of the properties of substances, namely the density of a liquid, and can be used to measure the density of media in the food and other industries.

According to the main auth. No. 765705 is known a float densitometer containing a float sinking in a liquid, a disk mounted on a shaft and a float balancing device with a cam shaped element located on the same shaft with a disk, with a hole in the disk, the geometry of which is identical to the geometry of the cam1, and the distance between the disk and the cam is equal to or greater than their thickness.

When the density of the controlled fluid changes, the ejector force of the float changes and, consequently, its apparent weight, as a result of which the disk and involute cam rotate until they are counterbalanced by countercurrent moment created by the load.

When the disk and involute cam are rotated, the radius of winding of the load cable changes, t, e, the involute arm, on which the load LlJ acts, changes.

The disadvantage of this densitometer is the low measurement accuracy due to the unevenness of the scale due to the fact that the shoulder y1 of the load-carrying weight changes according to a law different from the law of the involute cam profile, since the balance weight cable is not at the point on the horizontal axis of the cam, but in points located at a distance below the horizontal axis.

The purpose of the invention is to improve the accuracy of measurements.

The goal is achieved by the fact that in the float densitometer of fluid the axis of the profiled element, the passage through the medium-sized radii of the involutes, is located with respect to the vertical axis of the float at an angle of 15-30 °, and the second axis is perpendicular to the first.

Figure 1 shows the float densitometer fluid, a longitudinal section, and the position of its moving elements with a minimum value

2 is the same, the plan and position of its moving elements with the minimum density value is controlled by the fluid tM; in FIG. 3, a cam for explaining the method of building a profiled element; in FIG. 4, a cam in the form of one details, the axis of which, passing through the middle radii, is located to the vertical axis of the float at an angle of 15-30 with the minimum density of the measured liquid; Fig. 5 shows a profiled element consisting of two identical involute cams symmetrically located on the same shaft with the disk.

The float liquid density consists of a float (Figures 1 and 2) suspended on a cable 2 to a rotating disk 4 on the axis 3, on the circular surface of which there is a groove 5 for fastening and winding the float cable. On disk 4, a service scale 6 of the densitometer is plotted, and the second scale 7 is on the surface of the drum 8 attached to the disk 4. Opposite the rotating cabinet 6 and 7 there is a fixed pointer 9. On axis 3 next to the dis-. The cam 4 is fixed to the cam 10 in the form of one piece with two symmetric involute profiles: the right-hand worker 11 and the left balancing t2 with a linear dependence of the curvature profile and the groove 13 on the involute surface for securing and winding the cargo cable 14 on which the load 15 hangs.

The geometrical axis of the cam (Fig. 4, which passes through the medium-sized radii of involutes 3-9, is rotated about the vertical axis of the float by 15-30 °, and the second axis 6-0 is perpendicular to the first one.

With this arrangement of the axes of the profiled element, the length of the shoulder of the balancing weight varies according to the involute law, which allows to obtain a uniform scale and improve the measurement accuracy.

The meter is equipped with a capacitive remote transducer for transmitting readings to a secondary device (not shown).

The capacitor rotor of the remote capacitive converter converters of two equal, but opposite and electrically isolated parts (halves) 16 and 17, each of which consists of the same number of plates in the form of one and equal half of a circle, fixed on axis 3 so that one half of the rotor 16 is located on the right, and the second half 17 is on the left of axis 3, while the plates of the right 16 and left 17 halves of the rotor together make full disks with a uniform mass distribution relative to the axis of rotation v have the same balance operated and steadiness as a solid disc. The stator capacitor of the remote capacitive converter also consists of two equal halves, one 18 of which is located opposite the right side 16 of the rotor, and the second 19 opposite the left side 17 of the rotor. Equal halves of the stator are mounted on the densitometer body (hatching in Fig. 1), Axis 3 is on two ball bearings 20 and 21. The float is in vessel 22, through which the controlled fluid flows continuously. The capacitive differential transducer of the densitometer is differentially connected either to the inductive-capacitive bridge of the electronic level indicator of the type ED1U-2, or to the working and double voltage circuit of the capacitive level gauge, the output of which is connected to a second instrument, for example, such as an automatic speed controller. then the electrical system (not noKasami). The densitometer works as follows (in its own way. For a float immersed in a liquid, the following equation is valid:, eVp t, (i) where iTn is the mass of weights, balancing pp in the gpdd liquid, is the mass of weights that balance the float when weighed in air (f is the volume the float at the measurement temperature / p - iinoTHocTb of the controlled liquid at the measurement temperature. When the density of the controlled liquid changes, it changes (the apparent weight of the float 1, resulting in a change in the moment of the float M, turning the axis 3 of the densitometer until will be balanced by the opposing moment Mp created by the mass of the load 15 in the air nif. Equilibrium equation: Mn-.w, Ri re-RK, n A VB-KK, (3), where R. is the radius of the disk (shoulder of constant size), through which the float is immersed in the liquid, on the axis of the densitometer Rfc is the cam radius (variable shoulder) through which the load acts on the axis of the densitometer. By substituting the value of m from equation (1) into equation (3), after conversion we get pv-l, Dl the specific design of the density meter and mfg, R. t are constant, therefore, P i-iUK) ,. . (5) i.e. when the density of the controlled fluid varies, the radius of the winding of the cargo cable on the solvent surface of the cam 10 changes, i.e. The length of the beam changes over which the mass of the load 15 acts. The axis 3 of the densitometer rotates through a certain angle, and the angle of rotation of the axis 3 linearly depends on the density of the liquid. An arrow 9 is fixed on the stationary housing of the densitometer, indicating the density value on the rotating scales 6 and 7. In addition, the tight meter readings are transmitted to the secondary device when POM1TSi capacitive remote transducer, the change in capacitance is also proportional to the angle of rotation of the axis 3 and the density of the liquid. TaKj, for example, when increasing the density of the fluid, the axis 3 rotates clockwise, the plates of the left half of the capacitor rotor 17 enter the gaps between the stator plates 19 and the capacitance increases, and the plates of the right part 16 exit the gaps of the stator plates 18 and the capacitance decreases. .

So the left and right half of a capacitor converter are included differentially in the adjacent arms of an electronic level indicator of the EIU-2 type or in a working and compensation circuit for doubling the capacitive level gauge, the sensitivity of remote transmission is doubled compared with the capacitor capacitance.

To simplify and reduce the cost of manufacturing a densitometer, it is advisable to make the disc solid, and to perform a shaped element with two symmetric involute profiles. Such a design will make it possible to use a density meter in those measuring sets of automatic float density meters, in which capacitive or resisin converters are used as remote transducers, the rotors of which can rotate up to 180.

The profiled element can be made in the form of two involute cams with the same geometry and mass, symmetrically placed on the same shaft with the disk. Such a design is advisable when used as remote transforms of differential-transformer and ferrodynamic types.

The method of building a profiled element with two symmetric involute profiles: draw a disk disk at a scale of 1: 1; divide the disk area with lines no less than 12 equal sectors (the more equal sectors, the more accurately you can draw a cam profile with a linear dependence), assign sector numbers with Roman numerals, and define sector beams in Arabic from 0 to 11 (FIG. 3) , a horizontal diameter of 6-0 divides the cam into two equal parts} mark the beginning and end of the scale on the disk circumference.

With a capacitive distance converter, the angle between the beginning and the end of the scale is 180, i.e. Nano and the end of the scale are not vertical disc diameter 3-9, with the beginning at point 3, and the end at point 9

diameter. With the minimum density of the controlled fluid, it is advisable to rotate the horizontal diameter of the 6-0 cam clockwise to

15-30. In this position of the cam, the shoulder of the countering moment is: at the minimum density P (figure 4) of the beginning of the scale and at the maximum density - P of the end of the scale.

In FIG. 1, the cam is rotated by 30, and in FIG. A, by 15 °. After turning the cam clockwise to 15, the beginning of the scale will be at point A (figure 4), and the end at point B.

The difference between the radius Pj of the cam at the beginning of the scale and the radius p | the end of the scale is divided by the number of sectors of the scale:

"- - Вк 62-38 Р

mm

For the values of y, it is necessary to continuously reduce the length of the adjacent beam along the direction. The ends of the reduced rays are located on the cam curve (figs 3 and 4) and are indicated by circles.

The results of the calculations are shown in the table.

. Number 40 of the beam O 1

23456

Put on the disc rays the ends of the radii of the cam and connect these points

smooth line.

With other remote transformations, for example, with differential transformer, the angle between the beginning and the end of the scale is in

within 270-300. For such a remote converter, the cam should consist of two patterns with the same geometry and mass, located symmetrically with respect to

to the vertical diameter of the disk (figure 5).

Thus, rotation of the geometrical axes of the profiled element in the vertical plane relative to the vertical axis of the float at angles of 15-30 ° allows to obtain a fully uniform scale of the densitometer, which improves the measurement accuracy. When used in a densitometer, typical remote converters Tdifferential transformer, ferrodynamic, resulphous, pneumatic and electropower transducers of the FPG and others can also be used to balance the masses of moving parts using two involute cams symmetrically placed on a single shaft with a disk. The proposed densitometer can be used in the systems of automatic control of the density of liquids in the food and other industries of the national economy.

FIG. five

Claims (1)

FLOATING DENSITY OF LIQUID according to author P 765705, characterized in that, in order to increase the accuracy of measurements, the axis of the profiled element passing through the average involutes for the length of the mustache is located with respect to the vertical axis of the float at an angle of 15-30, and its second axis is perpendicular to the first. W9 "11 1 1136063