SU721702A1 - Float density meter - Google Patents

Description

one

The invention relates to the field of measuring the density of liquids, and can be used in the petroleum, chemical, petrochemical, food and other industries.

Known float densimeter containing a vessel with a liquid, float, capacitive transducer and the recorder 1.

A disadvantage of the known densitometer is the small change in the output signal parameter, the complexity of the electrical circuit and the small measurement accuracy.

The closest to the technical essence of the present invention is a float density meter containing a body connected to the supply and removal system of the measured liquid, inside of which is placed a movable float with a permanent magnet, a temperature compensation system and a recorder 2.

The disadvantages of the prototype are:

a small change in the electrical parameter of the output signal with a change in density and, as a consequence, the need to use complex electrical circuits; in inductive sensors, the signal varies nonlinearly and relatively within narrow limits, which

requires the use of bridge circuits and expensive secondary recording devices;

inconsistency of characteristics with changes in working conditions, such as temperature, humidity of the external medium, liquid composition, etc .;

these sensors are powered, as a rule, from high-frequency voltage sources, which require special generators; This is due to the fact that only when using high-frequency currents for power supply their sensitivity is realized and the stability of the operation of the measuring circuits is ensured;

the requirement for precise manufacture of individual parts of the sensor.

The aim of the invention is to simplify the design and increase reliable operation of the device.

The goal is achieved by the fact that, in the proposed densitometer, the float is made in the form of a ring with a magnet attached to it and is movably mounted on a tube with ferromagnetic fluid mounted on a housing in which two constantan conductors connected by movable

mercury contact and included in the registrar circuit.

The densitometer consists of body 1, float 2 with magnet 3, tubes of diamagnetic material 4, high-resistance conductors 5 of constant, mercury contact 6, ferromagnetic fluid 7, indicating device 8, power source 9, thermal resistance 10, plugs 11 and 12, sealing ring 13, discharge tube 14, supply tube 15, diaphragm 16, constant pressure vessel 17, inlet tube 18.

The proposed densitometer works as follows.

Fluid through the inlet pipe 18 enters the overflow vessel 17, which provides a constant head, and from there through the inlet pipe 15 into the main body 1, which is also equipped with an overflow device. The required flow rate is set by means of the diaphragm 16. When the density of the controlled liquid 19 in the housing 1 changes, the float 2 with the magnet 3 pops up or lowers (due to the change of the buoyant force acting on the float according to Archimedes law). This force is balanced by the mass of the float depending on the depth of its immersion, i.e. the volume of its part submerged in the liquid. When moving the float, the contact 6 is moved from the mercury held by the internal pressure of the column of ferromagnetic fluid 7 that is in the field of the constant magnet 3. (The mercury contact takes a certain position relative to the upper edge of the constant magnet and follows the position of the float and does not change, reliably closure conductors from constantan).

Mercury contact 6 closes certain segments of conductors from constantan, changes their length, and accordingly, the resistance at the output of the converter. The change in ohmic resistance determines the density of the fluid. The two conductors 5 of constantan are connected in series with the indicating device 8 and the power source 9. A change in resistance in this series circuit causes a change in the current detected by device 8. To correct the readings for temperature changes, this circuit includes a thermal resistance 10. Tube 4 with ferromagnetic liquid for reliable operation is sealed by an o-ring 13 and plug 11. For removing the float

2 or its replacement (on other density ranges) there is intended a stopper 12, to which a tube with ferromagnetic fluid 4 is tightly fixed.

In the proposed device, the output signal is increased due to the fact that the conductor consists of a constantan drive, for example, with a diameter of up to 0.3 mm and more, and a mercury contact, through which high currents of up to several hundred milliamperes can be passed, thus eliminating the use of complex electrical circuits, which include: generator, amplifier, bridge circuit.

At the output of the densitometer, a powerful output signal (current) is obtained, which can be used without prior amplification directly to the actuators: a relay, a compensation coil, if the meter is operated with electrical feedback.

Claims (2)

Invention Formula A float densitometer comprising a housing connected to a supply and removal system of the measured liquid, inside of which a movable permanent magnet float is placed, a temperature compensation system and a recorder, characterized in that, in order to simplify the design and increase the reliability of the measurement, the float rings and fixed on It is magnetically and movably mounted on a tube with ferromagnetic fluid fixed to the housing, in which two constantan conductors are placed, which are closed by a moving mercury contact and connected to the recorder circuit. Sources of information taken into account during the examination 1. I. I. Glybin. Automatic density meters and concentration meters in the food industry. 1975, p. P.. 2. USSR author's certificate number 389489, cl. G 01 N 9/22, 197.