RU35567U1 - Device for measuring the density of liquid media - Google Patents

Description

The utility model relates to the technique of measuring physical quantities and can be used to measure the density of liquid media in open and closed tanks, pipelines and apparatuses operating under pressure.

A device is known for measuring the density of liquid media, see USSR author's certificate No. 935744 class. G01N 9/18, 1992, containing a flow-through housing, a measuring float in the form of a differential inductor with a core.

A disadvantage of the known device is the lack of measurement accuracy due to the presence of friction in the system of block cables, the dynamic pressure of the analyzed liquid on the float, and the presence of dissolved air or gas in the liquid, which is typical for industrial solutions transported through pipelines using centrifugal pumps.

In addition, the known device has a relatively low overall performance. Indeed, in order to balance the diffuser and the core on the block, and it is 20-30 times lighter than the coil (as described), the buoyancy of the float should be approximately equal to the weight of the coil and directed upward. And since the float, being in the liquid, is not centered by anything, when it vibrates or moves the liquid, it will certainly lose equilibrium (vertical position) and the measurement system will fail. A device for measuring the density of liquid media is also known.

comprising a flow-through housing with a cover, a float with a core located in the field of a differential inductor, a float displacement system with a block and a cable, and a measuring device.

Compared with the previous analogue, the device is characterized by increased stability, since the residual weight of the float (the weight of the float immersed in the liquid) is equal to the weight of the differential coil, i.e. the weight of the coil and the float is directed downward, adding up, create sufficient stability to the measurement system, however, the friction force in the system of block cables increases, which leads to an additional measurement error.

Other disadvantages of the known device that adversely affect the measurement include the effect of dynamic pressure on the float, as well as the saturation of the medium with air or gas.

In addition, the above devices are comparatively cumbersome due to the significant volume of the float, which is necessary in this case to increase the buoyancy force in order to partially compensate for the friction forces in the system of block cables.

A device for measuring the density of liquid media, containing a flowing housing with a cover, a float with a core located in the field of a differential inductor, and a measuring device, it is also equipped with two elastic plates and a measuring vessel, rigidly connected to the housing cover and having a throttle in the lower part the hole and the limit stop, the upper edge of the vessel is located below the line of liquid overflow in the flow housing, and the float together with the core is placed in the measuring vessel and m elastic plates zafeplennyh the top and bottom of the float is rigidly connected with it. Throttle

2 hole is located on the side opposite from the inlet pipe

wall of the measuring vessel. The limit stop is made with the possibility of vertical movement. See RF patent No. 2084864 for the invention of kp. G 01N 9/18, 1993

This invention is taken as the closest analogue (prototype).

The prototype has the following disadvantages:

- the presence of elastic elements for hanging the float in the working position significantly limits the range of variation in the density of the measured liquid to an average of 10%, which is unacceptable for a number of products of the petrochemical and gas industry. In particular for liquefied hydrocarbon gases, where the range of density changes in the same working volumes, depending on temperature, can be 20%, as well as for other low-boiling liquids;

the weighted working position of the float on the elastic elements limits the range of pressure change of the measured liquid to several atmospheres (textile, food industry), since with a wide range of pressure changes in the pipeline or working volume (five, ten, twenty times ... up to 50 atm., which takes place in the petrochemical and gas industries) the need for the notorious strength of the float will lead to such a significant increase in its weight that the density component in the force of the action of the measured liquid on the float the avoc will become unacceptably small, and the increase in the stiffness of the elastic elements caused by this phenomenon will nullify the measured range of the density of the measured fluid;

the weighted working position of the float and the need to adjust it by adding (removing) fractions to it when setting to the required range of density change of the measured liquid, makes

3 impossible to use the specified device for measuring density

liquids related in their chemical composition but significantly different in density and alternately flowing through the same pipelines and working volumes, for example, various petroleum products kerosene, gasoline, liquefied hydrocarbon gases, in this case, you will need to repeatedly configure the device for the required range of density changes, you will need also stopping the process, opening the device, its certification after mechanical adjustment.

The technical result and the task of the proposed utility model are to expand the range of changes in density and pressure in the working volumes of the measured fluid, thus expanding technological capabilities, increasing reliability and durability, simplifying the design.

This is achieved by new technical solutions that are in a causal relationship with the technical result.

The essence of the claimed device is expressed in the aggregate of the following essential features.

In a device for measuring the density of liquid media containing a flowing housing with covers, a float rigidly connected to the core, a measuring vessel with a throttling hole rigidly connected to the cover, distinguishing features from the prototype are:

a bellows separator is installed on the cover of the flow-through housing for filling it with measuring liquid, as well as a glass in which the pressure transducer is placed;

an electromagnet is installed on another lid with the possibility of interaction with the specified core;

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4 the core is mounted movably along the axis of symmetry of the device and

abuts against the working element of the pressure transducer.

The above set of essential features in comparison with the prior art allows us to conclude that the proposed technical solution meets the criterion of "novelty.

The drawing shows the proposed device for measuring the density of liquid media in the context.

The device comprises a flowing housing 1 with covers of the upper 2 and lower 3. Covers using gaskets and bolted joints hermetically close the flowing housing. A measuring vessel 5 with a throttling hole 17 is rigidly fixed on the bottom cover 3 with struts 16. The float 4 is completely fixed in the measured liquid 28 along the symmetry axis of the measuring vessel 5 and is completely immersed in the measured liquid 28. The core 15 is mounted movably with the possibility of axial movement in the fluoroplastic guides 10, 29. On the top cover there is an electromagnet 8, designed to raise the float using the traction pad 19 when setting up the device.

The pulling pad 19 is located on the core 15. The cam retirement 9 is designed to fix the float during assembly, transportation and installation of the device in any unit. A measuring vessel with a baffle wall 27 protects the float from the dynamic impact of flowing in the housing of the measured liquid 28. The throttling hole 17 in the upper part of the casing on its side wall, located on the side opposite to the supply to the measured liquid, through the pipe 25, provides hydrostatic alignment of densities liquid in the stream and in the near-float space under the measuring vessel, which, if

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temperatures in these spaces ensures the identity of the properties of the liquid in the stream and under the measuring vessel.

The location of the throttling hole on the opposite side relative to the inlet pipe 25 favorably affects the process of degassing the liquid, as well as the anti-clogging of the throttling hole. A bellows medium separator 21 is mounted on the bottom cover 3 and is placed in the housing 7 having an opening 20 through which the measured liquid 28 fills this housing. A cup 24 is also mounted on the bottom cover. The internal cavities of the bellows separator 21 and the cup 24 are connected by a pipe 23 and are filled with a measuring fluid 11. A pressure strain gauge 6 with electrical leads 12 is placed in the cup 24 through a sealed insulator. Through the hole 22, the measuring fluid fills the chamber 30 in the pressure transducer casing 6. The measuring liquid (transformer oil, glycerin, etc.) is filled with a bellows medium separator, pipe, glass, chamber 30 in the pressure transducer casing without any air in them.

The core 15 with its end 31 during measurements constantly abuts against the working element 18 of the pressure transducer. On the top cover 2 there is a safety valve 13 for emergency pressure relief and a pressure gauge 14 for monitoring pressure and a temperature sensor.

The device operates as follows. The measured liquid 28, passing through the inlet pipe 25, fills the flow housing 1 and flows out through the pipe 26. Using a bellows separator of the media 21 in the measuring liquid 11 located in the chamber 30, a pressure equal to the pressure of the measured liquid inside the flow housing 1 is created.

depending on the density of the measured liquid, a submersible float, which obviously has negative buoyancy, the end 31 of the core 15 acts on the working element 18 of the strain transducer with one or another (greater or lesser) force. As a result, an electrical signal is generated that enters through the electrical leads 12 into a measuring circuit, where it is converted into an information or control signal, for example, for automatic control systems.

To check the absence of the pressure of the measured fluid on the working element of the pressure transducer 18 using an electromagnet 8, raise the float, check the readings of the pressure transducer pressure, which should be close to zero.

The utility model is confirmed by the following formula

Fon P - Tear. R RZh - Use. (kg)

Rop-R

RJ (kg / m),

Upl.

where is Torn. - buoyant force acting on the float from the side of the measured liquid and depending on the density of this liquid (kg);

P is the weight of the float in air (kg);

P op - negative buoyancy of the float, the force acting on the working element of the pressure transducer pressure as a result of the combined action on the float of its weight and the Archimedean ejection force from the side of the measured fluid (kg);

Upl. - volume of the float (m);

РЖ - density of the measured liquid (kg / m). From the above equation it can be seen that in the absence of measurable

liquids in a flowing housing from a strain gauge sensor pick up a signal proportional to the weight of the float, which is used to calculate the density value of the measured liquid.

When the magnet is on and in the presence of pressure in the flow housing 1, the same pressure is created in the cavity with the measuring fluid 11 and the working element 18 of the pressure transducer does not deform and does not give any signals to the measuring circuit.

When the magnet is off, the device only responds to the effect of the float, the negative buoyancy of which depends on the density of the measured liquid.

Based on the foregoing, it can be argued that the proposed device is feasible in industry and has the following indicators:

- sufficiently high measurement accuracy;

- comparatively small dimensions;

-expanded measurement range, as it can be used to measure the density of liquid media open and under pressure in various industries of trade and economy such as chemical, textile, food, in the distribution and dispensing of products such as liquefied petroleum gas, gasoline, kerosene, as well as other high or low boiling liquids;

- simplicity of design that does not require mechanical adjustment when changing or replacing the measured fluid or changing its pressure.

According to the proposed device, design documentation has been developed, device samples have been manufactured and tested. Tests have yielded positive results.

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Claims (1)

A device for measuring the density of liquid media, containing a flowing housing with covers, a float rigidly connected to the core, a measuring vessel with a throttling hole, characterized in that it is equipped with a bellows separator for filling the measuring liquid with a glass and a glass in which the strain gauge is placed pressure, while the specified core is mounted movably with emphasis in the working element of the pressure transducer, and an electromagnet with zhnosti interaction with said core.