CN201673102U - Densimeter - Google Patents

Abstract

The utility model discloses a densimeter, which overcomes the technology defect that the existing densimeter is difficult to complete the fluid density measurement in petroleum and landification operations. The densimeter comprises a first measurement pipe which comprises a first port and a second port and is capable of accommodating the fluid; a second measurement pipe which comprises a first port and a second port and is capable of accommodating the fluid; a drive device for driving the first measurement pipe and the second measurement pipe to vibrate; a resonance frequency calculating device for calculating the resonance frequencies of the first measurement pipe and the second measurement pipe when receiving a resonance signal transmitted by a judge circuit and calculating the density of the fluid according to the resonance frequencies; the judge circuit which is connected with the first measurement pipe, the second measurement pipe and the drive device, wherein, when the first measurement pipe and the second measurement pipe achieve the resonance states, the judge circuit can transmit the resonance signal to the drive device. The utility model can be used for measuring the fluid density in the petroleum and landification operations, and the utility model has advantages of high measurement precision, wide measurement range, simple structure and convenient mounting and changing.

Description

Densitometer

Technical field

The utility model relates to a kind of gauging instrument, specifically, relates to a kind of densitometer.

Background technology

Tubular vibration-type densitometer is a kind of densitometer commonly used, is mainly used in the normal temperature and pressure environment of ground, and its basic functional principle is that object is excited and when vibrating, its vibration frequency or amplitude are relevant with the quality of object itself.If fill in object with the volume of fluid sample, just then its vibration frequency or oscillation amplitude change reflect the quality of this fluid sample, and the quality of sample is directly proportional with its average density, can obtain the density of fluid sample in view of the above.

Advantages such as tubular vibration-type densitometer is simple in structure with it, but the high density measurement scope of measuring accuracy is wide are used widely.But typical tubular vibration-type densitometer, mainly be subjected to the restriction of temperature, pressure, material and mode of operation etc., under high temperature and high pressure environment, use and be subjected to bigger restriction, for oil well logging formation testing operation and other petroleum and petrochemical industry operations, be difficult to extract the density of measuring institute's withdrawn fluid (oil, gas, water three-phase, and mud filtrate) under the high temperature and high pressure environment.

In view of this, be necessary to propose a kind of densitometer, under high temperature and high pressure environment, to carry out the measurement of fluid density.

The utility model content

Technical problem to be solved in the utility model, being to provide a kind of densitometer, overcomes existing densitometer and be difficult to finish the technological deficiency that fluid density is measured in the petroleum and petrochemical industry operation.

In order to solve the problems of the technologies described above, the utility model provides a kind of densitometer, and this densitometer comprises first measuring tube, second measuring tube, drive unit and decision circuitry, wherein:

This first measuring tube comprises first port and second port, holds fluid;

This second measuring tube comprises first port and second port, holds fluid;

This drive unit drives this first measuring tube and second measuring tube and vibrates; When receiving the resonance signal that this decision circuitry sends, calculate the resonance frequency of this first measuring tube and second measuring tube, and according to the density of this resonance frequency Fluid Computation;

This decision circuitry links to each other with this first measuring tube, second measuring tube and this drive unit, sends this resonance signal to this drive unit when this first measuring tube and second measuring tube reach resonant condition;

Wherein, the first port UNICOM of second port of this first measuring tube and this second measuring tube, first port of this first measuring tube is as the inlet of fluid, and second port of this second measuring tube is as the outlet of fluid.

Wherein, this densitometer further comprises:

Mount pad fixedly mounts this first measuring tube and second measuring tube;

Contiguous block is fixedlyed connected with second measuring tube with this first measuring tube, for this first measuring tube and second measuring tube provide the vibration fulcrum.

Wherein, this first measuring tube and second measuring tube are fixedly mounted on this mount pad with the tapering sealing means by clamp nut.

Wherein, first port of this first measuring tube and second port are fixedly mounted on this mount pad with the tapering sealing means by clamp nut;

First port of this second measuring tube and second port are fixedly mounted on this mount pad with the tapering sealing means by clamp nut.

Wherein, this first measuring tube and second measuring tube are beam type U type pipe, and the two amplitude when vibration takes place equates that direction of vibration is opposite.

Wherein, this first measuring tube and second measuring tube are made for the small frequency temperature coefficient alloy material.

Wherein, this drive unit comprises first field coil, second field coil and counting circuit, wherein:

This first field coil is for this first measuring tube and second measuring tube provide vibrational energy;

This second field coil detects the vibrational state of this first measuring tube and second measuring tube, and the electromotive force at two ends is sinusoidal wave state;

Counting circuit receives this resonance signal, measures the sine wave freuqency at these second field coil two ends, by the density of this sine wave freuqency Fluid Computation.

Compared with prior art, the utility model can be easily installed on the wireline logging instrument, can be used for the petroleum and petrochemical industry operation and carry out the measurement of fluid density, has the measuring accuracy height, and measurement range is wide, and is simple in structure, installs, changes advantages such as convenient.

Description of drawings

Fig. 1 is the Facad structure synoptic diagram of the utility model densitometer embodiment;

Fig. 2 is the side structure synoptic diagram of the utility model densitometer embodiment;

Fig. 3 is the structural representation of drive unit among the Figure 1 and Figure 2 densitometer embodiment.

Embodiment

Describe embodiment of the present utility model in detail below with reference to drawings and Examples, how the application technology means solve technical matters to the utility model whereby, and the implementation procedure of reaching technique effect can fully understand and implements according to this.

Fig. 1 is the Facad structure synoptic diagram of the utility model densitometer embodiment, and Fig. 2 is the side structure synoptic diagram of the utility model densitometer embodiment.Please consult Fig. 1 and Fig. 2 simultaneously, the utility model densitometer embodiment mainly comprises first measuring tube 10, second measuring tube 20, drive unit 30 and decision circuitry 40, wherein:

This first measuring tube 10 comprises first port one 1 and second port one 2, accommodates fluid 15;

This second measuring tube 20 comprises first port 21 and second port 22, accommodates fluid 15;

This drive unit 30, be installed in the centre of this first measuring tube 10 and second measuring tube 20, drive this first measuring tube 10 and second measuring tube 20 vibrates, when receiving the resonance signal of these decision circuitry 40 transmissions, calculate the resonance frequency of this first measuring tube 10 and second measuring tube 20, according to the density of resonance frequency Fluid Computation 15;

This decision circuitry 40, link to each other with this first measuring tube 10, second measuring tube 20 and drive unit 30, judge whether this first measuring tube 10 and second measuring tube 20 reach resonant condition, when judging this first measuring tube 10 and second measuring tube 20 and reach resonant condition, send these resonance signals to this drive unit 30;

Wherein, second port one 2 of this first measuring tube 10 and first port, 21 UNICOMs of this second measuring tube 20, first port one 1 of this first measuring tube 10 is as the inlet of fluid 15, and second port 22 of this second measuring tube 20 is as the outlet of fluid 15.Certainly, in actual applications, this outlet and inlet also can be exchanged as required.

Comprise first field coil, second field coil and a counting circuit in this drive unit 30, wherein:

First field coil provides vibrational energy for first measuring tube 10 and second measuring tube 20;

Second field coil detects the vibrational state of first measuring tube 10 and second measuring tube 20, and the electromotive force at these second field coil two ends is sinusoidal wave state;

Counting circuit, when this first measuring tube 10 and second measuring tube, 20 arrival resonant conditions, can receive this resonance signal that decision circuitry 40 sends, at this moment, the sine wave freuqency at these second field coil two ends equates with resonance frequency, by measuring the density that this sine wave freuqency can calculate first measuring tube 10 and second measuring tube, 20 inner fluids.

Densitometer shown in Figure 1 can also comprise a mount pad 50 and a contiguous block 60, wherein:

Mount pad 50 fixedly mounts this first measuring tube 10 and second measuring tube 20;

Contiguous block 60 is fixedlyed connected with second measuring tube 20 with this first measuring tube 10, for this first measuring tube 10 and second measuring tube 20 provide the vibration fulcrum, makes first measuring tube 10 and second measuring tube 20 not influenced by outside erection stress.

First measuring tube 10 and second measuring tube 20, be two beam type U type pipes, be fixed on this mount pad 50, four ports of two U type pipes (first port one 1 of first measuring tube 10 and second port one 2, and first port 21 of second measuring tube 20 and second port 22) are fixed on the mount pad 50 with the tapering sealing means by clamp nut 80.First measuring tube 10 and second measuring tube 20 are made for the small frequency temperature coefficient alloy material, the two amplitude when vibration takes place equates, direction of vibration is opposite, and fluid wherein can be at least a or several combination in oil, rock gas, water and the mud filtrate.

Under the driving of this drive unit 30, this first measuring tube 10 and second measuring tube 20 are disturbed Qu Zhendong in the opposite direction, when this vibration reaches the resonance attitude, measure resonance frequency by drive unit 30, can obtain the density of U type tube fluid.

Shown in Figure 1 this first measuring tube 10 and second measuring tube 20 are made for the small frequency temperature coefficient alloy material, this first measuring tube 10 equates with this second measuring tube 20 amplitude when autovibration takes place, direction of vibration is opposite, and its vibration frequency is not disturbed by extraneous vibration.

Densitometer of the present utility model, employing is from the excited resonant measuring method, with vibrating tube (i.e. first measuring tube 10 and second measuring tube 20) as oscillator, rely on feedback control loop to keep the resonance attitude of vibrating tube, the resonance frequency of measuring vibrations pipe obtains density of medium in the vibrating tube, be applicable to the density of measuring fluid (oil, gas, water three-phase, and mud filtrate) under the high temperature hyperbaric environment such as petroleum and petrochemical industry operation (as oil well logging formation testing operation etc.).

If ignore the crooked influence in single U type vibrating tube top, U type pipe can be approximately straight tube.According to theory of elastic mechanics,, there is the described relation of formula (1) at the natural period of oscillation and the mass of system of straight tube during in vibration when the shape of straight tube and material fixedly the time:

$T_n=2\mathrm{\π}\sqrt{\frac{M_t+{\mathrm{\ρ}}_f{V}_f}{K}}---\left(1\right)$

Wherein:

T _nIt is the n rank natural period of object vibration;

K is an instrument constant, and is relevant with the shape and the material of vibrating tube;

M _tIt is the quality of vibrating tube;

ρ _fBe the density of tube fluid;

V _fBe the volume of tube fluid, ρ _fV _fIt promptly is the tube fluid quality.

Can get by formula (1) arrangement:

${\mathrm{\ρ}}_i=\frac{1}{V_f}(\frac{K}{4{\mathrm{\π}}^2}{T}_n^2-M_t)---\left(2\right)$

Wherein:

ρ _iDensity for the vibrating tube inner fluid of flowing through.

In the vibration mechanics theory, the free vibration attenuation cycle of object vibration and natural period of oscillation approximately equal, so formula (2) can understand like this, and under vibrating tube shape and material one stable condition, the density p of the vibrating tube of flowing through inner fluid _iOnly become quadratic function relation with the vibrating tube free vibration attenuation cycle.In the actual application, generally adopt formula (3) to calculate vibrating tube inner fluid density:

ρ _i＝K ₂T ²+K ₁T+K ₀ (3)

Wherein:

K ₀, K ₁And K ₂, be calibration factor;

T is harmonic period.

In densitometer of the present utility model, the vibration of U type pipe relies on drive unit 30 to realize, it is the device of mechanical force with electrical signal conversion that drive unit 30 can be selected for use typical.

Fig. 3 is the structural representation of drive unit 30 among the Figure 1 and Figure 2 densitometer embodiment.As shown in Figure 3, drive unit 30 comprises first solenoid 31 and second solenoid 32 of reverse installation, the first permanent magnet magnetic core 35 with 31 couplings of first solenoid, the second permanent magnet magnetic core 36 with 32 couplings of second solenoid, drive the driving circuit 39 of first solenoid 31 and second solenoid 32, and aforesaid first field coil 33 and second field coil 34.

The amplitude that it should be noted that the mechanical vibration of U type pipe can not surpass U type pipe safety allowed band, otherwise U type pipe is fragile.Therefore, the enlargement factor of amplifier and driving force should be used and restriction to some extent according to reality.

Certainly, the number of turn of first solenoid 31 and second solenoid 32, the diameter of the used enameled wire of coil and temperature performance, permanent magnet magnetic core material and parameter, and the physical dimension between them all is vital for the normal starting of oscillation of U type pipe.Driving circuit 39 uses for being fit to high temperature and high pressure environment, and selected device is high-temperature device, can work among 175 ℃ of environment.

Densitometer of the present utility model, owing to need to adapt to the severe rugged environment of high temperature high pressure such as down-hole, therefore its ingredient should adapt to special application conditions such as down-hole, and wherein first measuring tube 10 and second measuring tube 20 select for use the small frequency temperature coefficient alloy material to make.This alloy material has less temperature elasticity coefficient, higher Qm, good velocity of wave consistance, higher intensity and elastic modulus, less retarded elasticity and hysteretic properties, premium properties such as linear expansion coefficient is low, and processing characteristics is better and corrosion-resistant.

Below with regard to the temperature elasticity coefficient of U type pipe (ThermoElastic Coefficient TEC), withstand voltage and corrosion resistance does further explanation, is an example with the down-hole application environment of harshness:

(1) under the violent condition of temperature variation, the elasticity of U type pipe keeps constant substantially.Because the well temperature changes between to 177 ℃ subzero, and the elastic modulus of the densitometric resonance frequency of the utility model and U type pipe is 1/2 proportional, and it is zero that the TEC value of U type pipe is approximately, and guaranteed densitometric accuracy of measurement of the utility model and precision.

(2) downhole fluid pressure is generally all very high, and under extreme case, down-hole pressure may be up to 140Mpa, and the U type tube material in the utility model densitometer has favorable mechanical mechanical property and dimensions, has guaranteed the serviceability under hyperbaric environment.

(3) drilling fluid of down-hole, resident fluid etc. all are the very strong fluids of corrosivity, and densitometer of the present utility model promptly is that these fluids are measured, and the U type tube material in the utility model densitometer has guaranteed the densitometric resistance to corrosion of the utility model.

A kind of tubular vibration-type densitometer that can in high temperature and high pressure environment, measure resident fluid density that the utility model proposes, can be easily installed on the wireline logging instrument such as formation tester, by driving and metering circuit is finished under the oil well high-acruracy survey of fluid density in the High Temperature High Pressure rugged surroundings.

Densitometer commonly used in the present high temperature and high pressure environment, mainly contain two kinds of gradiomanometer tool and radioactive density meters, the former measuring accuracy is subjected to the influence of fluid velocity etc., latter's measuring accuracy mainly is subjected to the influence of statistical fluctuation error, and in construction, to operate radioactive source, human body and environment are easily damaged.

The utility model tubular vibration-type densitometer is compared with existing densitometer, and measuring accuracy is higher, and measurement range is wider, and structure is also simpler, and installation, replacing etc. are convenient.The vibrating tube material that filters out from a large amount of alloy materials has that little temperature elasticity coefficient, high Qm, good velocity of wave consistance, higher intensity and elastic modulus, less retarded elasticity and hysteresis, linear expansion coefficient are low, a good processability, corrosion resistance etc. preferably.Be applicable to the high temperature drive system under the high temperature and high pressure environment, convert electrical energy into mechanical energy and drive double u-tube, and when the fluid of certain density range is flowed through vibrating tube inside, still keep the vibration of pipe with resonance frequency generation vibration.In addition, driving circuit produces self-sustained oscillation and constitutes degenerative driving and metering circuit with the vibrating tube drive system, makes drive system can maintain resonant condition, by measuring harmonic period Fluid Computation density.

Though the disclosed embodiment of the utility model as above, the embodiment that described content just adopts for the ease of understanding the utility model is not in order to limit the utility model.Technician under any the utility model in the technical field; under the prerequisite that does not break away from the disclosed spirit and scope of the utility model; can do any modification and variation what implement in form and on the details; but scope of patent protection of the present utility model still must be as the criterion with the scope that appending claims was defined.

Claims (7)

1. a densitometer is characterized in that, comprises first measuring tube, second measuring tube, drive unit and decision circuitry, wherein:

This first measuring tube comprises first port and second port, holds fluid;

This second measuring tube comprises first port and second port, holds fluid;

This drive unit drives this first measuring tube and second measuring tube and vibrates; When receiving the resonance signal that this decision circuitry sends, calculate the resonance frequency of this first measuring tube and second measuring tube, and according to the density of this resonance frequency Fluid Computation;

This decision circuitry links to each other with this first measuring tube, second measuring tube and this drive unit, sends this resonance signal to this drive unit when this first measuring tube and second measuring tube reach resonant condition;

Wherein, the first port UNICOM of second port of this first measuring tube and this second measuring tube, first port of this first measuring tube is as the inlet of fluid, and second port of this second measuring tube is as the outlet of fluid.

2. densitometer according to claim 1 is characterized in that, this densitometer further comprises:

Mount pad fixedly mounts this first measuring tube and second measuring tube;

Contiguous block is fixedlyed connected with second measuring tube with this first measuring tube, for this first measuring tube and second measuring tube provide the vibration fulcrum.

3. densitometer as claimed in claim 2 is characterized in that:

This first measuring tube and second measuring tube are fixedly mounted on this mount pad with the tapering sealing means by clamp nut.

4. densitometer as claimed in claim 3 is characterized in that:

First port of this first measuring tube and second port are fixedly mounted on this mount pad with the tapering sealing means by clamp nut;

First port of this second measuring tube and second port are fixedly mounted on this mount pad with the tapering sealing means by clamp nut.

5. densitometer as claimed in claim 1 is characterized in that:

This first measuring tube and second measuring tube are beam type U type pipe, and the two amplitude when vibration takes place equates that direction of vibration is opposite.

6. densitometer as claimed in claim 5 is characterized in that:

This first measuring tube and second measuring tube are made for the small frequency temperature coefficient alloy material.

7. densitometer as claimed in claim 1 is characterized in that this drive unit comprises first field coil, second field coil and counting circuit, wherein:

This first field coil is for this first measuring tube and second measuring tube provide vibrational energy;

This second field coil detects the vibrational state of this first measuring tube and second measuring tube, and the electromotive force at two ends is sinusoidal wave state;

Counting circuit receives this resonance signal, measures the sine wave freuqency at these second field coil two ends, by the density of this sine wave freuqency Fluid Computation.

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