CN202648859U - Liquid manometer calibrated by sound velocity in real time - Google Patents
Liquid manometer calibrated by sound velocity in real time Download PDFInfo
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- CN202648859U CN202648859U CN 201220298858 CN201220298858U CN202648859U CN 202648859 U CN202648859 U CN 202648859U CN 201220298858 CN201220298858 CN 201220298858 CN 201220298858 U CN201220298858 U CN 201220298858U CN 202648859 U CN202648859 U CN 202648859U
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Abstract
The utility model relates to a liquid manometer calibrated by sound velocity in real time. According to the liquid manometer, measurement of absolute pressure, gauge pressure and differential pressure can be realized. The liquid manometer comprises a sound velocity measuring system and a height measuring system, wherein the two systems are in high and low U-tube structures, and are connected to the same pressure to-be-measured position; the sound velocity measuring system is provided with buoys which freely suspend on the liquid level; the inside of each buoy is provided with a laser reflection component; the lower end surface of each buoy is a reflecting surface of ultrasound signals; and the bottoms of the U-tubes are provided with ultrasound chips. A method for measuring the pressure is that, a hydraulic difference corresponding to changes is generated between the high and low tubes when pressure is enforced on the low tube of the U-shaped high and low tubes; a laser interferometer and an ultrasound interferometer measure the displacement of the buoys and the corresponding ultrasound echo time in real time, and the sound velocity in real time is obtained; the height measuring system, according to the sound velocity, together with the ultrasound interferometer, measures the transit time of the ultrasound in the liquid medium under the pressure, and a liquid column height difference is obtained on the basis of the sound velocity measured by the sound velocity measuring system, and thus the to-be-measured pressure is measured. According to the liquid manometer, through an improved structure of the measuring device, the signal to noise ratio of the ultrasound receiving signals is substantially improved, and the measurement uncertainty of the liquid manometer is substantially reduced.
Description
Technical field
The utility model relates to a kind of liquid manometer, relates in particular to a kind of liquid manometer with velocity of sound real-time calibration function, and the actual name of the liquid manometer of a kind of velocity of sound real-time calibration that the utility model relates to is (0-10) kPa minute-pressure fluid pressure benchmark.
Background technology
Because the liquid manometer of pin-point accuracy can directly be traced to the source to fundamental quantity and by various countries metering mechanism extensively as the national pressure reference below the air pressure section.In China, the slight pressure section below 10kPa is not all set up corresponding disjunction mark standard apparatus all the time.(0-10) foundation of kPa minute-pressure fluid pressure benchmark will be improved the accurate system of pressure disjunction mark of China, fill up the blank of this range section pressure disjunction mark standard of China, solve the difficult problem of tracing to the source of this range section whole nation pressure criteria.
For China's existing pressure base establishment of standard situation, absolute pressure measurement at 10kPa always is blank, in order to fill up the blank of the following China of 10kPa pressure reference, improve the accurate system of disjunction mark of China, satisfy requirement and lifting China CMC ability that the pressure that day by day increases is traced to the source and transmitted, we have proposed the application, be intended to by setting up the liquid pressure measurement system and method for cover (0～10) kPa minute-pressure section, realize simultaneously gauge pressure, the measurement of absolute pressure and differential pressure, fill up the blank of China's minute-pressure pressure reference, further improving the accurate system of the existing pressure disjunction mark of China, better is the national economy service.
(0-10) kPa minute-pressure fluid pressure benchmark is based on hydrostatic equilibrium principle and hydrostatic equilibrium equation, and namely p=ρ gh obtains tested force value by accurate measurement fluid density ρ, local gravitational acceleration g and the poor h of liquid-column height.Wherein local acceleration of gravity is recorded in October, 2011 by my acceleration of gravity chamber, institute mechanics place, and its value is 9.801260m/s
2, its uncertainty of measurement is 0.1ppm.Fluid density is recorded by my institute density chamber, its uncertainty of measurement is 5.8ppm, the difference in height of liquid is passed the ultrasound wave of fluid column from being transmitted into the time of reception by measurement, adopt the method for ultrasonic interference, utilizing superhet to connect device, quadrature phase-sensitive detection device and gated integrator accurately measures because the variation of the phase place that the variation of liquid-column height causes, uncertainty of measurement during its is 0.3ns, and corresponding height uncertainty of measurement is about 0.6um.The uncertainty of minute-pressure fluid pressure benchmark is 0.003%.
In the prior art, Chinese patent CN2247804Y provides a kind of supersonic digital micro-pressure difference meter, and its characteristics are as follows:
1) adopting distilled water is actuating medium.
Because the room temperature saturated vapor pressure very high (being about 2000Pa) of water is only suitable for the measurement of gauge pressure, is not suitable for the measurement of absolute pressure.
2) adopt standard pipe to come caliper velocity.
The length of prior art by the standard pipe measured is in advance getted over distance as reality is hyperacoustic.In fact, hyperacousticly get over distance and differ greatly with the length of standard pipe, mainly be because: ultrasonic wafer is posted on the fixed head by bonding agent is sticking, and the ultrasound wave of therefore ultrasonic wafer emission also will pass through certain thickness bonding agent, and the thickness of bonding agent is difficult to measure; Sonac must be tightly connected by fluororubber O-type ring or polytetrafluoro pad and standard pipe in addition, and the gasket seal of this form all can have deformation when compressing, therefore cause in fact the length of ultrasound wave standard pipe can't accurately measure (measuring error is greater than 1mm) at all, so strictly, although the length of standard pipe can accurately be measured, its length is not the actual distance that ultrasound wave passes through this standard pipe.The velocity of sound of therefore demarcating in this way has larger measuring error.
3) do not adopt the temperature stabilization measure.
Because the velocity of sound in the liquid is very responsive to temperature, per 0.1 ℃ of temperature variation can be brought the variation of about 0.03% the velocity of sound, if therefore there not be all even stable temperature fields, the height measurement of fluid column has very large error.
The utility model content
Can't measure absolute pressure and can't be as the accurate accurately problem of gaging pressure of disjunction mark in order to solve liquid manometer of the prior art, the utility model provides a kind of liquid manometer that can realize velocity of sound real-time calibration.
(0-10) kPa minute-pressure fluid pressure benchmark can be realized the measurement of small gauge pressure, differential pressure and absolute pressure.Mainly comprise U-shaped tubular container system, ultrasound measurement system, temperature measurement system, acoustic velocity measutement system, pneumatic control system, vacuum chamber and hoisting mechanism and data acquisition processing system.It is liquid-working-medium that benchmark adopts Di-2-ethlhexyl sebacate (DEHS), in order to solve liquid medium to the phenomenon of seeking connections with of canister wall, we have adopted a kind of oleophobic teflon coatings, and in the acoustic velocity measutement system, designed and produced special float mechanism, realize first the real-time measurement of the velocity of sound, in order to get rid of temperature, pressure to the impact of the velocity of sound.U-shaped tubular container system places within the vacuum chamber, and the pressure in the vacuum tank is less than 10Pa, to avoid outside air to the seepage of system and to keep the stable of liquid manometer temperature in the vacuum tank.6 standard platinum resistance thermometers are distributed in the different parts of liquid manometer, and package unit is realized the automatic acquisition and processing of data by computing machine, 3499 on-off controllers and testing software.
The know-why that the utility model adopts and scheme
The minute-pressure fluid pressure benchmark of (0～10) kPa is based on the principle of work of U-shaped liquid manometer, namely puts on the gravity that the tested pressure p of U-shaped Guan Yiduan produces with the poor h of liquid-column height that causes therefrom and balances each other, that is:
p=r gh
R is the density of liquid medium in the formula, and g is local acceleration of gravity.
In 3 of the following formula major effect amounts that determine the pressure sizes, acceleration of gravity and density can accurately record with correlation method, are the most critical factors that determines the liquid manometer performance index and how accurately to measure liquid-column height poor.
It is its liquid-working-medium that the minute-pressure fluid pressure system of (0～10) kPa adopts Di-2-ethlhexyl sebacate (DEHS), adopt ultrasonic superhet method measure ultrasound wave by liquid medium the time from being transmitted into the transit time of reception, thereby the acoustic velocity measutement system of fluid pressure benchmark is by obtaining the velocity of ultrasonic sound under different pressures and the temperature to the in real time measurement of velocity of sound this moment simultaneously, again during the sound thus the time and the velocity of sound to calculate liquid-column height poor, and finally obtain the pressure surveyed.
The two ends of the U-shaped pipe of traditional U-shaped liquid manometer are on the same surface level, when tested pressure-acting during in an end of U-shaped pipe, liquid decline 1/2h among the U-shaped Guan Yiduan, liquid rising 1/2h in the U-shaped pipe other end, at this moment, if the density of hydraulic fluid is r, local acceleration of gravity is g, then tested pressure p=r gh.If that is to say the pressure that will measure p=r gh size, the height of U-shaped pipe two ends single armeds (single tube) need to reach the height of h.
The two ends of the U-shaped pipe of the U-shaped containment system of the minute-pressure fluid pressure benchmark of (0～10) kPa are respectively seated on two platforms that drop is 500mm.When U-shaped pipe pressure at two ends equates, liquid in the U-shaped pipe is on the same level face, when pressure p=when ρ gh acts on the low pipe that is in lower position, the height of liquid level decline 1/2h in the low pipe, the height of the liquid level rising 1/2h of liquid in the senior executive, because the existence of U-shaped pipe drop, at this moment to measure the pressure of p=r gh size, U-shaped pipe two ends single armeds (single tube) as long as height reach the height of 1/2h.The purpose that designs like this, can greatly reduce the length of U-shaped pipe single armed, so that the height of liquid has reduced half in the single armed, solved ultrasound wave larger difficult problem of signal attenuation in the oily medium particularly in liquid medium, so that the signal to noise ratio (S/N ratio) of ultrasonic reception signal improves greatly.
Method when utilizing ultrasonic measurement sound in the utility model is finally measured liquid-column height.Measuring method during ultrasonic sound has multiple, and wherein the pulse echo that has commonly used is counted method, Pulse-echo Method, pulse echo method of superposition and ultrasonic interferometric method.Rear both absolute whens sound of measuring media very critically under given conditions.The measurement in ultrasonic when sound that comprises in the utility model adopts ultrasonic interference technique to measure the travel-time of ultrasonic signal in fluid column, and its principle is to measure the phase differential j of ultrasound echo signal and initialize signal.
The initial ultrasound signal can be represented by the formula:
y
0=A
0 cos(2p ft) (2-1)
A wherein
0Be the amplitude of initialize signal, f is the frequency of signal, and its initial phase is made as 0.Echoed signal in fluid column behind propagation one segment distance then is:
y=Acos(2p ft+j) (2-2)
Wherein A is the amplitude of echoed signal,
For having comprised the phase place of ultrasonic signal propagation distance information in fluid column.The pass of phase place and signal propagation time T is:
j=-2p fT (2-3)
Wherein T is the travel-time, is included in travel-time and the time-delay in circuit in the fluid column.If ultrasonic time-delay in circuit is stable, the difference in travel-time namely is the difference in when sound in the fluid column so; Also can adopt the phase differential (or sound time difference) of second echo and first echo, so corresponding time just is the travel-time in fluid column.
Adopt the signal y after 90 ° of phase shifter phase shifts during specific implementation
0=A
0Y before sin (2p ft) and the phase shift
0=A
0Cos (2p ft) is reference signal, and reference signal and echoed signal are behind quadrature phase transformation detector, and high-frequency signal is filtered, only the remaining low frequency signal u that contains transformation information j
1=sinj and u
2=cosj, thus j obtained
Acoustic velocity measutement system described in the utility model, its principle are when pressure changes, and the float of free-floating on liquid levels is that the liquid level tracking means can change along with the change of liquid level.Be installed on the ultrasonic wafer below the acoustic velocity measutement U-shaped pipe this moment, under the excitation of frequency synthesizer, produce the ultrasound wave of 2MHz, this ultrasonic signal passes the lower surface that liquid medium is transmitted into float, the lower surface of float is as the reflecting surface of ultrasonic signal at this moment, the ultrasound wave with the liquid level change information that reflects is received by ultrasonic wafer, and the variable quantity t-t when obtaining changing the sound cause owing to liquid level
0, simultaneously, laser interferometer measurement is to change the liquid level variable quantity (L-L that causes owing to pressure
0), thereby obtain the velocity of sound c of ultrasound wave in liquid medium.
In the formula: L
0Be respectively float with L and change the height value that the front and back laser interferometer records with liquid level;
t
0With t be respectively float change with liquid level before and after ultrasound measurement system record sound the time.
The technical solution of the utility model is as follows: a kind of liquid manometer of velocity of sound real-time calibration, and described liquid manometer comprises altitude measurement system, acoustic velocity measutement system, pneumatic control system, hydraulic control system and data acquisition and processing (DAP) system;
Described altitude measurement system and and velocity of sound measuring system comprise respectively one group of U-shaped pipe: highly measure U-shaped pipe and acoustic velocity measutement U-shaped pipe, be respectively applied to measure the transit time of ultrasound wave in liquid and measure the liquid level variable quantity and liquid level transformation period amount; Described height is measured the U-shaped pipe and described acoustic velocity measutement U-shaped Guan Jun is filled with a certain amount of liquid, and two groups of interior liquid of U-shaped pipe are communicated with;
Described acoustic velocity measutement system comprises liquid level measure of the change module and liquid level transformation period measurement module;
Described liquid level measure of the change module comprises two cover laser interferometer, two cover liquid level tracking means and two cover optical frames groups; Described optical frames group be arranged on respectively in the described liquid level tracking means and opticpath in, described liquid level tracking means suspends and is arranged on the real-time follow-up of realizing liquid level under the different pressures in the interior liquid of described acoustic velocity measutement U-shaped pipe, and described laser interferometer and described optical frames group realize the measurement of liquid level variable quantity △ L under the different pressures;
Described liquid level transformation period measurement module comprises two groups of ultrasonic wafers and ultrasonic interferometer; Described two groups of ultrasonic wafers are separately positioned on the bottom of described velocity of sound U-shaped pipe two arms, and described ultrasonic interferometer and described ultrasonic wafer obtain the time variation amount △ T that liquid level changes by the transit time of ultrasound wave in liquid of measuring certain frequency 2MHz～10MHz;
Described acoustic velocity measutement system is used for the time variation amount △ T that changes according to liquid level and because pressure changes the liquid level variable quantity △ L that causes, obtains the velocity of sound C of ultrasound wave in liquid medium;
Described altitude measurement system comprises that one group of height measures U-shaped pipe, two groups of ultrasonic wafers and ultrasonic interferometer; Described two groups of ultrasonic wafers are separately positioned on the bottom that described height is measured U-shaped pipe two arms, and described ultrasonic interferometer and described ultrasonic wafer record the transit time of ultrasound wave in liquid under the different pressures by measuring;
Described pneumatic control system is used for controlling the described pressure of respectively organizing U-shaped pipe two ends; Pneumatic control system comprises control rack, by-pass valve control pipeline, pump group and one group of supervisory instrument; Described pump group is used for the extraction of finding time of two groups of U-shaped pipe reference edges and gaseous tension; Described by-pass valve control pipeline is connecting described altitude measurement system and described acoustic velocity measutement system, realizes the adjusting of shutoff, connection and pressure size between them; Described control rack is realized the control to described by-pass valve control pipeline and described pump group;
Described hydraulic control unit comprises the vacuum storage tank, and connecting fluid road and valve between the U-shaped pipe are logical and disconnected for what the liquid road between filling liquid in the described U-shaped pipe and each arm of U-shaped pipe was connected;
Described data acquisition and processing (DAP) system is used for control and various temperature, pressure and the supervisory instrument data acquisition of on-off controller, and the time variation amount △ T and the liquid level variable quantity △ L that change according to the liquid level of described acoustic velocity measutement system input, obtain the velocity of sound C of ultrasound wave in liquid medium, highly measured the difference in height of U-shaped intraluminal fluid post according to the transit time of ultrasound wave in liquid under the measured different pressures of described altitude measurement system afterwards, through the pressure that finally obtains after the necessary parameter correction surveying.
Problem that can't the Measurement accuracy standard length when solving acoustic velocity measutement in the prior art, designed unique liquid-level tracking device and the length during with acoustic velocity measutement is directly traced to the source to laser frequency, described liquid level tracking means places the liquid in the acoustic velocity measutement U-shaped pipe of described acoustic velocity measutement system, and its structure is float, and it comprises floating drum, pyramid mirror fixed mount, floating ear group and guide rail; Described floating ear group is arranged on the upper surface outside of float, and is provided with guide rail bearing in a floating ear, and described guide rail passes the bearing in this described floating ear; Described pyramid mirror is fixed on the described pyramid mirror fixed mount, and described pyramid mirror fixed mount is fixed on center in the described floating drum; Described float floats on a liquid, and moves up and down freely along with the up and down variation of liquid level, and does not have horizontal shift.
In order to overcome in the prior art signal attenuation and to improve signal to noise ratio (S/N ratio), described altitude measurement system and and the included height of velocity of sound measuring system two arms of measuring U-shaped pipe and acoustic velocity measutement U-shaped pipe be height layout straggly; Difference in height scope between senior executive and the low pipe is 200mm-800mm;
Described acoustic velocity measutement U-shaped pipe and highly measure the U-shaped pipe and respectively comprise 2 stainless-steel tubes; 4 stainless-steel tube equal lengths.4 described stainless-steel tubes consist of 2 groups of U-tube manometers, between every group of U-shaped pipe between the corresponding high-low pipe and link to each other respectively between two U-shaped pipes, and respectively organize switch between U-shaped pipe two arms and the switch between two groups of U-shaped pipes by valve control.
In the described liquid level measure of the change module, described every cover optical frames group comprises a pyramid mirror and a composite mirrors, and a described pyramid mirror is arranged in the described float, and described composite mirrors is arranged on the opticpath;
The laser that described laser interferometer is sent incides on the pyramid mirror that is positioned at float central authorities by composite mirrors, and the reflection of process pyramid mirror, obtain the reflected light parallel with incident light, reflected light obtains the height number that float changes with liquid level again by being received by laser interferometer after the composite mirrors.
4 groups of described ultrasonic wafers are separately positioned on the bottom that described height is measured U-shaped pipe and acoustic velocity measutement U-shaped pipe two arms, the ultrasound wave of the certain frequency that the ultrasonic wafer of described acoustic velocity measutement U-shaped pipe produces passes liquid medium, the lower surface of arrival described float of lifting with the liquid level lifting, the lower surface of float is as the reflecting surface of ultrasonic signal, the ultrasonic signal with the liquid level variable signal that reflects is received by ultrasonic wafer, the variable quantity △ T when obtaining because liquid level changes generation sound.
For constantly monitoring temperature variation, described liquid manometer also comprises temperature measurement system, and described temperature measurement system comprises one group of standard platinum resistance thermometer and bridge for measuring temperature; Each described standard platinum resistance thermometer evenly is fixed on described two groups of U-shaped pipe outer walls; Described bridge for measuring temperature and described standard platinum resistance thermometer record the temperature signal of each point, are connected with described data Collection ﹠ Processing System simultaneously, realize the collection of temperature and the processing of data.
For the variation that solves temperature in the prior art impact on the velocity of sound, promote to the utmost the measurement level, described liquid manometer has designed vacuum chamber, highly measure the U-shaped pipe and acoustic velocity measutement U-shaped pipe is arranged in the vacuum chamber, and the vacuum tightness in the vacuum chamber remains under the pressure less than 10Pa, to reduce heat conduction and thermal convection by mechanical pump.
The problem of seeking connections with in order to solve the liquid of prior art in measurement, the inwall of 2 groups of described U-shaped pipes and the outer wall of float are provided with teflon coatings.
Another inventive point of the utility model is exactly the measuring method that adopts foregoing liquid manometer,
Described method comprises: A builds the liquid manometer process, B pressure control procedure, C measuring process, D acquisition and processing data procedures;
Described method comprises: A builds the liquid manometer process, B pressure control procedure, C measuring process, D acquisition and processing data procedures;
Described A builds the liquid manometer process and comprises altitude measurement system, the acoustic velocity measutement system, and pneumatic control system, hydraulic control system, temperature measurement system and data acquisition and processing (DAP) system, vacuum chamber connects by circuit and various operation valve;
Described B pressure control procedure comprises carries out pressure control to U-shaped pipe two ends, realizes the measurement of gauge pressure, differential pressure and absolute pressure;
Described C measuring process comprises, adopts ultrasonic interferometric method to measure the transit time of ultrasound wave in liquid; And carry out the real-time measurement of the velocity of sound; The method for real-time measurement of the described velocity of sound: the variable quantity when adopting laser interferometer and ultrasonic interferometer to measure respectively the sound of distance that the liquid level tracking means moves and mobile this distance and obtain the real-time velocity of sound under the conditions such as working temperature, pressure;
Concrete measuring process comprises opens each measuring equipment, and to 2 in 2 groups of U-shaped pipes low pipe pressurizations, described laser interferometer and described ultrasonic interferometer are by measuring displacement △ L and the time △ T of liquid level tracking means under this temperature and pressure, obtain hyperacoustic velocity of sound under this temperature and pressure, ultrasonic interferometer in the described altitude measurement system is by measuring the transit time T of ultrasound wave in liquid medium, and the velocity of sound that obtains according to described acoustic velocity measutement system, thereby the height that obtains fluid column finally obtains being recorded pressure.Namely jointly realize the measurement of liquid-column height by altitude measurement system and velocity of sound measuring system;
Described D acquisition and processing data procedures comprises, described data acquisition and processing (DAP) system utilizes on-off controller to read as required the Temperature numerical of each point, gather simultaneously the measurement data of acoustic velocity measutement system and altitude measurement system and the numerical value of each supervisory instrument, obtain tested force value to the calculating of all measurement results and after finishing necessary correction.
Liquid in the described U-shaped pipe is Plexol 201.
The beneficial effect that the utility model brings is as follows:
1) the utility model adopts U-shaped high-low pipe drop layout, owing to have drop between two single tubes in the U-shaped high-low pipe, when therefore measuring the pressure of p=r gh, only need make two liquid level drops in the single tube reach 1/2h and get final product.Therefore, so that the single tube height has reduced half, solved ultrasound wave larger difficult problem of signal attenuation in the oily medium particularly in liquid medium, so that the signal to noise ratio (S/N ratio) of ultrasonic reception signal improves greatly.
2) the utility model has adopted the Thermo Isolation Technique of certain ingredients, and liquid manometer is placed a vacuum cavity, and therefore the vacuum tightness in the cavity greatly reduced thermal convection and heat conduction less than 10Pa, makes the temperature of liquid manometer uniform and stable.
3) the utility model adopts Plexol 201 to replace distilled water as actuating medium, and the saturated vapor pressure under its normal temperature is about 5 * 10
-6Pa, the saturated vapor pressure (2000Pa) much smaller than distilled water is more suitable for the measurement of absolute pressure.
4) length-measuring error of laser interferometer is less than 0.1um, therefore utilize laser interferometer to measure in real time the displacement of float and ultrasonic echo time that float moves this distance and obtain the in real time velocity of sound, greatly reduce the uncertainty of measurement of liquid manometer, make uncertainty be reduced to 0.003% by 0.03%.
5) the utility model has adopted the Teflon spray treatment to the U-shaped pipe, has solved the seek connections with problem of liquid at vessel surface, and the uncertainty that liquid level is measured reduces greatly.
Description of drawings
Fig. 1 is the structural representation of the liquid manometer of a kind of velocity of sound real-time calibration of the utility model;
Fig. 2 is the structural representation of the utility model U-shaped pipe group;
Fig. 3 is U-shaped pipe group gas circuit and liquid road connection diagram in the utility model;
Fig. 4 is acoustic velocity measutement and temperature survey work synoptic diagram in the utility model;
Fig. 5 is the structural representation of float in the utility model;
Fig. 6 is the structural representation of pneumatic control system in the utility model
Detailed description of main elements:
1-acoustic velocity measutement U-shaped pipe; 2-highly measures the U-shaped pipe; The 3-float; The 4-laser interferometer;
The 5-vacuum cavity; The 6-temperature sensor; The 7-bridge for measuring temperature; The 8-signal processing system;
The 9-ultrasonic interferometer; 10-pyramid mirror; The 11-reflective mirror; The 12-floating drum; 13-pyramid mirror fixed mount;
The ultrasonic wafer of 15-; The 16-pneumatic control system; The 17-hydraulic control system; 18-surveys high shut-off valve;
19-velocity of sound shut-off valve; 20-surveys height/velocity of sound shut-off valve; 21-vacuum (-tight) housing Pirani gauge;
The 22-on-off controller;
The dried pump of 1601-; 1602-the first oil pump; The 1603-Pirani gauge; The 1604-high pressure nitrogen;
The 1605-digital pressure gauge; The 1606-decompressor; The 1607-micrometering valve; The 1608-pressure gauge;
The 1609-ionization gauge; The 1610-molecular pump; The 1611-diagram vacuum gauge
1701-vacuum storage tank; 1702-the second oil pump; 1703-the 3rd solenoid valve; 1704-the 4th ball valve;
E1-the first solenoid valve; E2-the second solenoid valve;
K1-the first shut-off valve; K2-the second shut-off valve; K3-the 3rd shut-off valve; K4-the 4th shut-off valve;
K5-the 5th shut-off valve; K6-the 6th shut-off valve; K7-the 7th shut-off valve; K8-the 8th shut-off valve;
K9-the 9th shut-off valve; K10-the tenth shut-off valve; K11-the 11 shut-off valve;
K12-the 12 shut-off valve; N1-the first needle-valve; N2-the second needle-valve; N3-the 3rd needle-valve;
N4-the 4th needle-valve; N5-the 5th needle-valve; B3-the first ball valve; B4-the second ball valve;
B5-the 3rd ball valve;
Below in conjunction with the drawings and specific embodiments the utility model is described in more detail, protection domain of the present utility model is not limited to following embodiment.
Embodiment
The two ends of the U-shaped pipe in the utility model in the liquid manometer of velocity of sound real-time calibration are respectively seated on two platforms that drop is 500mm, such as Fig. 1 or shown in Figure 2.When U-shaped pipe pressure at two ends equates, liquid in the U-shaped pipe is on the same level face, when pressure p=when r gh acts on the low pipe that is in lower position, the height of liquid level decline 1/2h in the low pipe, in the senior executive liquid level of liquid rise 1/2 and height, because the existence of U-shaped pipe drop, at this moment to measure the pressure of p=r gh size, U-shaped pipe two ends single armeds (single tube) as long as height reach the height of 1/2h.The purpose that designs like this, can greatly reduce the length of U-shaped pipe single armed, so that the height of liquid has reduced half in the single armed, solved ultrasound wave larger difficult problem of signal attenuation in the oily medium particularly in liquid medium, so that the signal to noise ratio (S/N ratio) of ultrasonic reception signal improves greatly.
As seen from Figure 1, U-shaped containment system is highly identical by 4, internal diameter is that the stainless-steel tube of 90mm is respectively seated at drop on two platforms of 500mm, in fact 4 stainless-steel tubes consist of 2 U-tube manometers, one of them U-tube manometer (right side two height stainless-steel tube) is used for the measurement of the velocity of sound, the U-shaped tube manometer in left side (two stainless-steel tubes in left side) is used for measuring by measuring pressure, link to each other respectively between the high-low pipe of the correspondence of two U-shaped tube manometers and between two U-shaped tube manometers, and have valve to be used to control through and off between them, to satisfy different measurement demands.When these are communicated with valve opening, liquid level in the two U-shaped tube manometers of cover (being the U-shaped meter of pressure survey and the U-shaped meter of acoustic velocity measutement) is along with the variation of pressure, identical variation occurs simultaneously, the U-shaped pipe that is used for like this velocity of sound namely can obtain the real-time velocity of sound under pressure and temperature condition this moment, be used for the time that tonometric U-shaped pipe can record according to this real target velocity of sound and ultrasonic interferometer, obtain this moment by measuring pressure.
Because the actuating medium that we use is Di-2-ethlhexyl sebacate (DEHS), this is the very little oil of a kind of saturated vapor pressure, and its vapor pressure can reach 10
-6Pa, but this oil has the stronger effect of seeking connections with to stainless steel, and in order to solve the seek connections with problem of this oil on the stainless steel inwall, we have selected the Teflon material that stainless-steel tube is processed: with the inwall of Teflon material spraying at 4 stainless-steel tubes.Through this processing, so that (DEHS) contact angle on stainless steel surfaces is increased to 56 ° from 14 °.Through experiment, adopt U-shaped containment system after the spray treatment of this material because the variation that acts on the liquid-column height that causes of seeking connections with of liquid medium is reduced to 3um by 20um.
The bottom of U-shaped containment system is useful on the pipeline that oil circuit is communicated with, and top is useful on the pipeline that gas circuit is communicated with, and the pipeline that is used for the oil circuit connection is 3/8 flexible pipe and joint, and being used for the gas circuit connecting pipeline is KF25, CF25 and corrugated tube.The oil circuit of U-shaped containment system is by shutoff, the shutoff between the pressure survey high-low pipe and the shutoff between the velocity of sound and pressure measuring tube between the interface on the vacuum cavity 5 and the valve realization velocity of sound high-low pipe, and the vacuum storage tank 1701 outside final and the vacuum cavity 5 links to each other; The gas circuit of U-shaped containment system realizes the shutoff of pressure end between reference edge between the velocity of sound and pressure measuring tube and the velocity of sound and pressure measuring tube by the interface on the vacuum cavity 5 and valve, and finally links to each other with pressure end with the reference edge of pneumatic control system 16.
The acoustic velocity measutement system comprises U-shaped pipe group, float 3 systems, laser interference length-measuring system and ultrasound measurement system.
Concrete, U-shaped guard system is in fact the part of U-shaped containment system, stainless-steel tube by two layouts straggly forms, two stainless-steel tubes are continuous by 3/8 inch flexible pipe, and link to each other with low pipe with the senior executive of pressure measuring tube by shut-off valve respectively, to realize the real-time measurement of ultrasound wave velocity of sound in oil under different pressures and the temperature conditions.U-shaped guard system gas circuit be connected with the liquid road structure be connected as shown in the figure.
The laser interference length-measuring system adopts XL80 laser interferometer 4 systems of two cover RENISSAW.This interferometer data stabilization, thermal value is little, and drift is little, and its uncertainty of measurement is less than 0.5ppm.Two laser interferometer 4 are separately fixed to be adjusted on the platform, can realize X, Y, Z and the adjustment of leaning forward, rolling; Spectroscope and reference mirror are fixed together, and by bolt tightening, prevent that relative displacement from causing measuring error.Spectroscope places on the adjusting bracket, and adjusting bracket can be regulated the adjustment of the directions such as X, Y, Z-direction and the angle of pitch and inclination angle.Three-dimensional prism (pyramid mirror) is fixed on the float frame that is installed in floating drum 3 central authorities.
The laser that laser head sends can see through the light hole that vacuum cavity 5 loam cakes are positioned at the U-shaped pipe of acoustic velocity measutement 1 top, incide on the pyramid mirror 10 that is positioned at float 3 central authorities, and the reflection of process pyramid mirror 10, obtain the reflected light parallel with incident light and received by laser interferometer 4, thereby realize the height that float 3 changes with liquid level.
In the utility model, temperature measurement system mainly is comprised of 6 standard platinum resistance thermometers 6, F18 bridge for measuring temperature 7.The 162D standard platinum resistance thermometer of 3 PT25 is arranged in 6 standard platinum resistance thermometers 6, and other 3 is the platinum-resistance thermometer of PT100.Five platinum-resistance thermometers 6 wherein are fixed in by heat-conducting block on the differing heights of 4 measuring tubes of the U-shaped container of liquid manometer, a bottom that is installed in liquid manometer pressure survey senior executive, and contact with liquid medium by copper tube.The installation site of six platinum-resistance thermometers 6 is such as figure.
These six platinum-resistance thermometers 6 link to each other with keithley3499 on-off controller 22 by the vacuum plug that is installed on the vacuum cavity 5, control choosing of 3499 switch passages by data Collection ﹠ Processing System, the temperature that six platinum-resistance thermometers 6 are obtained gathers.Adopt the 5685A(100OHM of Tinsley) as the measuring resistance of F18 bridge for measuring temperature 7, the uncertainty of F18 bridge for measuring temperature 7 is 0.1mk.
In the utility model, pneumatic control system 16 is mainly used in controlling the pressure of U-shaped pipe two ends (reference edge and pressure end).Pneumatic control system comprises that mainly control rack, by-pass valve control pipeline, molecular pump 1610, mechanical pump, film meter and various supervisory instrument form.Can realize the control and measurement of small gauge pressure, differential pressure and absolute pressure.
Among the figure, find time to hold the reference edge into system, link to each other with the reference edge of U-shaped containment system with KF25 interface on the vacuum cavity 5 by corrugated tube, live end is pressure end, links to each other with the pressure end of U-shaped containment system with KF25 interface on the vacuum cavity 5 by corrugated tube.The 6th shut-off valve K6 is for connecting the by-pass valve of reference edge and pressure end, and the vacuum of reference edge guarantees that by the molecular pump 1610 that is connected in reference edge the diagram vacuum gauge of 1torr and the digital pressure gauge of 130kPa are used for the supervision of reference edge pressure; The pressure transmitting medium of pressure end is high pure nitrogen, and its pressure can be finely tuned and by the 10kPa digital differential pressure gauge pressure end be monitored by micrometering valve 1607.System adopts the Trivac D60C of Leybold or the mechanical pump of IWATA ISP500C to carry out finding time of system.
When carrying out the measurement of absolute pressure, at first open the 6th shut-off valve K6 of reference edge and pressure end and open molecular pump 1610 and mechanical pump is found time simultaneously to reference edge and pressure end, then close the 6th and turn-off K6 and the second needle-valve N2, open the 3rd ball valve B5 and add needed pressure by micrometering valve 1607 to pressure end, when carrying out the measurement of absolute pressure, remain the evacuated of 1610 pairs of reference edges of molecular pump, pneumatic control system 16 at the pressure that carries out absolute pressure its reference edge when measuring usually about 0.03Pa.
When carrying out the measurement of differential pressure, at first open the 6th shut-off valve K6, the second needle-valve N2 and the 3rd ball valve B5 of reference edge and pressure end, add needed reference pressure by micrometering valve 1607 to reference edge afterwards, then close the 6th shut-off valve K6 and the second needle-valve N2, can carry out the measurement of differential pressure.。
The utility model comprises that also vacuum cavity 5 is one and is 8mm by 4 thickness that radial reinforced rib arranged the stainless steel cylinder is folded to fall to forming that the diameter of cavity is 800mm, highly is 1800mm.Be fixedly linked by clip between the cylinder; The upper cover plate of cylinder is that thickness is the aluminium sheet of 36mm, and two glass light holes are arranged on the cover plate, the light inlet window of laser when being used for acoustic velocity measutement; One KF40 flange-interface is arranged at the bottom of casing, links to each other with vacuum pump; A resistance vacuum gauge is connected in lower box by the KF16 mouth, is used for monitoring the pressure in the vacuum tank; The oil pump 1602 that the dried pump 1601 that pumping speed is 81/s and pumping speed are 16l/s is used for the maintenance of vacuum cavity 5 interior vacuum tightnesss, and the pressure in the cavity is remained in the 10Pa.On the vacuum chamber 6 CF25 interfaces are arranged simultaneously, wherein two are used for linking to each other with pressure end with the reference edge of pneumatic control system 16, other 4 are divided into two groups of reference edge and pressure end that connect respectively U-shaped containment system height measuring tube and velocity of sound measuring tube, wherein between height measuring tube and the velocity of sound measuring tube senior executive (reference edge), a flapper valve is all arranged between height measuring tube and the low pipe of velocity of sound measuring tube (pressure end), can control and realize its free switch.
Data acquisition and processing system has been realized the automatic collection of ultrasonic when sound and temperature in the utility model.During operation, the on-off controller 22 of the 3499A that can automatically switch carries out proceeding measurement to 6 platinum-resistance thermometers 6, the temperature of real time record current system.
Technique scheme is a kind of embodiment of the present utility model, for those skilled in the art, on the basis that the utility model discloses application process and principle, be easy to make various types of improvement or distortion, and be not limited only to the described structure of the above-mentioned embodiment of the utility model, therefore previously described mode is preferably, and does not have restrictive meaning.
Claims (9)
1. the liquid manometer of a velocity of sound real-time calibration is characterized in that:
Described liquid manometer comprises altitude measurement system, acoustic velocity measutement system, pneumatic control system (16), hydraulic control system (17) and data acquisition and processing (DAP) system (8);
Described altitude measurement system and velocity of sound measuring system comprise respectively one group of U-shaped pipe: highly measure U-shaped pipe (2) and acoustic velocity measutement U-shaped pipe (1), two groups of U-shaped Guan Zhongjun are filled with liquid, and two groups of interior liquid of U-shaped pipe are communicated with; Described altitude measurement system be used for to be measured ultrasound wave in the transit time of liquid and is calculated the height of fluid column according to the velocity of sound that described acoustic velocity measutement system records; Described acoustic velocity measutement system obtains the real-time velocity of sound by measuring liquid level variable quantity and liquid level transformation period amount;
Described acoustic velocity measutement system comprises liquid level measure of the change module and liquid level transformation period measurement module;
Described liquid level measure of the change module comprises two cover laser interferometer (4), two cover liquid level tracking means and two cover optical frames groups; Described optical frames group be arranged on respectively in the described liquid level tracking means and opticpath in, described liquid level tracking means suspends and is arranged in the liquid in the described acoustic velocity measutement U-shaped pipe (1) and realizes the real-time follow-up of liquid level under the different pressures, the measurement of liquid level variable quantity △ L under described laser interferometer (4) and the described optical frames group realization different pressures;
Described liquid level transformation period measurement module comprises two groups of ultrasonic wafers (15) and ultrasonic interferometer (9); Described two groups of ultrasonic wafers (15) are separately positioned on the bottom of described acoustic velocity measutement U-shaped pipe (1) two arm, and described ultrasonic interferometer (9) obtains the time variation amount △ T that liquid level changes with described ultrasonic wafer (15) by the transit time of ultrasound wave in liquid of measuring certain frequency 2MHz～10MHz;
Described acoustic velocity measutement system is by the time variation amount △ T that measures liquid level and change with because pressure changes the liquid level variable quantity △ L that causes, and obtains in real time the velocity of sound C of ultrasound wave in liquid medium by described data acquisition and processing (DAP) system (8);
Described altitude measurement system comprises one group of height measurement U-shaped pipe (2), two groups of ultrasonic wafers (15) and ultrasonic interferometer (9); Described two groups of ultrasonic wafers (15) are separately positioned on the bottom that described height is measured U-shaped pipe (2) two arms, described ultrasonic interferometer (9) and described ultrasonic wafer (15) by measure under the different pressures transit time of ultrasound wave in liquid and by described data acquisition and processing (DAP) system (8) thus the velocity of sound that the described acoustic velocity measutement of foundation system records calculates the variation of the caused liquid-column height of different pressures obtains the resulting pressure value;
Described pneumatic control system (16) is used for controlling the described pressure of respectively organizing U-shaped pipe two ends; Pneumatic control system (16) comprises control rack, by-pass valve control pipeline, pump group and one group of supervisory instrument; Described pump group is used for the extraction of finding time of two groups of U-shaped pipe reference edges and gaseous tension; The gas circuit that described by-pass valve control pipeline is connecting described altitude measurement system and described acoustic velocity measutement system realizes the adjusting of shutoff, connection and pressure size between them; Described control rack is realized the control to described by-pass valve control pipeline and described pump group;
Described hydraulic control system (17) comprises vacuum storage tank (1701), connecting fluid road and valve between the U-shaped pipe, and what be used for that the injection of described U-shaped liquid in pipe and the liquid road between each arm of U-shaped pipe connect is logical and disconnected;
Described data acquisition and processing (DAP) system (8) comprises computing machine and on-off controller (22); Described data acquisition and processing (DAP) system (8) utilizes on-off controller (22) to realize reading of different channel datas, and the time variation amount △ T and the liquid level variable quantity △ L that change according to the liquid level of described acoustic velocity measutement system input, obtain the velocity of sound C of ultrasound wave in liquid medium, obtain the difference in height of U-shaped intraluminal fluid post according to the transit time of ultrasound wave in liquid under the measured different pressures of described altitude measurement system afterwards, finally obtain the pressure of surveying.
2. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 is characterized in that:
Described liquid level tracking means places the liquid in the acoustic velocity measutement U-shaped pipe (1) of described acoustic velocity measutement system, and its structure is float (3), comprises floating drum (12), pyramid mirror fixed mount (13), floating ear group and guide rail; Described floating ear group is arranged on the upper surface outside of floating drum (12), and is provided with guide rail bearing in a floating ear, and described guide rail passes the bearing in this described floating ear; Described pyramid mirror fixed mount (13) is used for the pyramid mirror (10) in the fixing described optical frames group (10,11) and is fixed on the interior center of described floating drum (12); Described float (3) floats on a liquid, and moves up and down freely along with the up and down variation of liquid level, and does not have horizontal shift.
3. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 and 2 is characterized in that:
The included height of described altitude measurement system and velocity of sound measuring system measures U-shaped pipe (2) and acoustic velocity measutement U-shaped pipe (1) respectively comprises 2 stainless-steel tubes; Described two stainless-steel tubes are height layout straggly; 4 described stainless-steel tube equal lengths; And described acoustic velocity measutement U-shaped pipe (1) and the difference in height scope of highly measuring between the middle senior executive of U-shaped pipe (2) and the low pipe are 200mm-800mm;
4. the described stainless-steel tube of root consists of 2 groups of U-tube manometers, wherein said acoustic velocity measutement U-shaped pipe (1) is used for the measurement of the velocity of sound, another is highly measured U-shaped pipe (2) and is used for measuring ultrasound wave in the transit time of liquid, link to each other respectively between the high-low pipe of every group of U-shaped pipe and between two U-shaped pipes, and respectively organize switch between the U-shaped pipe high-low pipe and the break-make between two groups of U-shaped pipes by valve control.
The liquid manometer of 4 a kind of velocity of sound real-time calibrations according to claim 1 and 2 is characterized in that:
In the described liquid level measure of the change module, described every cover optical frames group (10,11) comprise a pyramid mirror (10) and a composite mirrors (11), a described pyramid mirror (10) is arranged in the described float (3), and described composite mirrors (11) is arranged on the opticpath;
The laser that described laser interferometer (4) is sent incides on the pyramid mirror (10) that is positioned at float (3) central authorities by described composite mirrors (11), and the reflection of process pyramid mirror (10), obtain the reflected light parallel with incident light, reflected light is received by laser interferometer (4) by composite mirrors (11) again, obtains the numerical value that liquid level changes.
5. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 and 2 is characterized in that:
4 groups of described ultrasonic wafers (15) are separately positioned on the bottom that described height is measured U-shaped pipe (2) and acoustic velocity measutement U-shaped pipe (1) two arm, the ultrasound wave of the certain frequency that the ultrasonic wafer (15) of described acoustic velocity measutement U-shaped pipe (1) produces passes liquid medium, arrive the lower surface of described float (3), the lower surface of float (3) is as the reflecting surface of ultrasonic signal, what reflect is received by ultrasonic wafer (15) with the ultrasonic signal of liquid level variable signal, thus obtain since liquid level change produce the time variable quantity △ T.
6. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 is characterized in that:
Described liquid manometer also comprises temperature measurement system, and described temperature measurement system comprises one group of standard platinum resistance thermometer (6) and bridge for measuring temperature (7); Each described standard platinum resistance thermometer (6) evenly is fixed on described two groups of U-shaped pipe outer walls; Described bridge for measuring temperature (7) and described standard platinum resistance thermometer (6) record the temperature signal of each point, are connected with described data Collection ﹠ Processing System (8) simultaneously, realize the collection of temperature and the processing of data.
7. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 is characterized in that:
Described liquid manometer comprises vacuum chamber (5), and 2 groups of described U-shaped pipes are arranged in the vacuum chamber (5), and the vacuum tightness in the vacuum chamber (5) remains on pressure less than 10Pa by mechanical pump.
8. the liquid manometer of a kind of velocity of sound real-time calibration according to claim 1 and 2 is characterized in that:
The outer wall of the inwall of 2 groups of described U-shaped pipes and float (3) is provided with teflon coatings.
9. the liquid manometer of described a kind of velocity of sound real-time calibration according to claim 1 is characterized in that:
Liquid in the described U-shaped pipe is Plexol 201.
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| CN 201220298858 CN202648859U (en) | 2012-06-19 | 2012-06-19 | Liquid manometer calibrated by sound velocity in real time |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220298858 CN202648859U (en) | 2012-06-19 | 2012-06-19 | Liquid manometer calibrated by sound velocity in real time |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103512700A (en) * | 2012-06-19 | 2014-01-15 | 中国计量科学研究院 | Liquid manometer with acoustic velocity calibrated at real time and pressure measuring method |
| CN107532931A (en) * | 2015-04-23 | 2018-01-02 | 东京瓦斯株式会社 | Gas meter, flow meter system and heating amount estimation method |
-
2012
- 2012-06-19 CN CN 201220298858 patent/CN202648859U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103512700A (en) * | 2012-06-19 | 2014-01-15 | 中国计量科学研究院 | Liquid manometer with acoustic velocity calibrated at real time and pressure measuring method |
| CN103512700B (en) * | 2012-06-19 | 2015-11-18 | 中国计量科学研究院 | A kind of fluid pressure of velocity of sound real-time calibration takes into account pressure measurement method |
| CN107532931A (en) * | 2015-04-23 | 2018-01-02 | 东京瓦斯株式会社 | Gas meter, flow meter system and heating amount estimation method |
| CN107532931B (en) * | 2015-04-23 | 2019-09-17 | 东京瓦斯株式会社 | Gas meter, flow meter system and fever amount estimation method |
| US11047720B2 (en) | 2015-04-23 | 2021-06-29 | Tokyo Gas Co., Ltd. | Gas meter system and heating value estimation method |
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Granted publication date: 20130102 Termination date: 20130619 |