CN104075773A

CN104075773A - Electromagnetic scale liquid level meter

Info

Publication number: CN104075773A
Application number: CN201410009316.7A
Authority: CN
Inventors: 宋德齐
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-09
Filing date: 2014-01-09
Publication date: 2014-10-01

Abstract

The invention discloses a key technology of an electromagnetic scale liquid level meter. The key technology of the electromagnetic scale liquid level meter is that Hall switch arrays serve as electrical signal scales, an electromagnetic ring suspended between two liquid interfaces or on the liquid surface serves as a reading pointer, and the magnetic field width at any position can cover a unique Hall switch compound state by controlling and changing the electromagnetic field width. State values of the Hall switch arrays are detected and subjected to configuration coding to obtain a current point position, and accordingly liquid level measurement is achieved. The electromagnetic scale liquid level meter has very high stability and measuring accuracy, a liquid level measuring product meeting the wide-range transaction metering-level product requirement does not exist in the disclosed prior art, and the electromagnetic scale liquid level meter fills the gap.

Description

Electromagnetism scale liquid level gauge

Technical field

Patent of the present invention discloses a kind of gordian technique of the metering level electrical measurement level gauging product of concluding the business.Product based on the art of this patent is by the level measuring being widely used in hydrologic observation, the level gauging of large-scale petroleum tank and chemical reagent tank, because it possesses the stability suitable with rule and measuring accuracy, it is the transaction level liquid level automatic measurement product of a alternative rule.

Background technology

At present level gauging has two kinds of modes, 1) artificial rule mode measures; 2) Electrical Measuring Instrument device is measured automatically.But the overwhelming majority accepts and believe artificial rule measured value when transaction metering level is measured, electric probe device is measured automatically as just the application of monitoring subsidiary.

The mankind are to rivers and lakes and the pool water-level observation of reservoir weir and record the history that has had more than one thousand years, always are the method observed stage that adopts label rule.In large oil tank and chemical solvent tank transaction metering level gauging, also only approve artificial rule measurement data.

Current electrical measurement liquid level equipment and instrument are approximately divided into two classes, be pressure measurement class and the survey time difference (phase differential) type (measure known average rate signal poor two-way time to liquid level from reference point, or measurement known periods signal coming and going phase differential from reference point to liquid level).Their principle, merits and demerits are separately as follows respectively:

1) pressure class level measuring instrument

With fluid pressure law, take the surveying instrument of thought research and development as the leading factor:

Y (liquid is to base pressure)=P (fluid density) * h (container bottom is to the vertical height of liquid level)

The principle of this quasi-instrument is adopt to measure liquid pressure to calculate liquid level, and the instrument that can measure theoretically pressure can be used for measuring liquid level, as silicon crystal liquid level gauge, type vibration wire osmotic pressure/liquid level gauge, differential resistance type osmotic pressure/liquid level gauge etc.

This quasi-instrument is arranged on container or reservoir area, bottom, riverbed, with cable, electric signal is drawn to liquid level, configures special readout instrument or automatic data collection unit image data.The major advantage of this quasi-instrument is simple in structure, and cost is low.Its major defect has measuring accuracy low (error minimum is 10 centimetres of left and right), general as auxiliary monitoring use, does not meet the requirement of metering class precision; It is larger that instrument is affected by temperature and sediment, needs regular calibration; The result of measuring is relative height, needs to convert to draw absolute elevation; Set-up time window is little, can only after dry season or emptying storage capacity, could install.

2) while surveying, survey phase class surveying instrument

As its name suggests, the two-way time that measurement sound wave, lightwave signal reflect back into reference point from reference point to liquid level is poor, by the time difference and speed, calculates distance, thereby calculates liquid level; Or phase differential when measurement sound wave, lightwave signal reflect back into reference point from reference point to liquid level, utilizes wavelength (phase place) and the corresponding relation of distance to calculate liquid level.

This quasi-instrument is arranged on liquid level top, adopts trestle or hanging stick mode to install, and this quasi-instrument has ultrasonic level gage, mangneto formula liquid level gauge, laser liquid level gauge etc.In this class liquid level gauge, relative merits differ greatly, below explanation respectively.

The major advantage of ultrasonic level gage is that measurement range is large, installs simply, and the set-up time is not subject to the restriction of season and current fluid level condition.Shortcoming is that error is very large, generally more than 25 centimetres, may produce once in a while the accidental singular value of 1～2 meter.And be subject to temperature and air humidity impact, should not measure for measuring level, can only use as auxiliary monitoring.

Mangneto formula liquid level gauge major advantage is that precision is high, installs simple.Shortcoming is that range is little, rod-type mangneto liquid level gauge range is generally no more than 3 meters, and flexible pipe mangneto liquid level gauge range is generally no more than 10 meters, and requires tested liquid level to keep relatively static, be subject to the interference of mechanical vibration, be obviously not suitable for using at physical environment or in having mechanical vibration environment.

Pulse type laser liquid level gauge precision is low, and error is large, and relative merits are similar to ultrasonic level gage.Phase type laser liquid level gauge precision is relatively higher than pressure class level measuring instrument, and range is large, but in most cases requires, at liquid level, cooperative target reflection is set, and to eliminate liquid transmission, refractive index is high and reflectivity is low impact, measurement mechanism is complicated.Cost is high, is subject to weather influence, need to often calibrate.These defects have restricted laser liquid-level and have used in physical environment and chemical flow container.

It is simple that the hydrologic observation of rivers and lakes seems, measuring accuracy (10 millimeters) requires also not high, but until today, remain a national technical barrier, engineering technological still fails to find a kind of automatic measurement scheme of received alternative artificial observation, the invention of the art of this patent, may change this situation.

Summary of the invention

(1) electromagnetism scale liquid level gauge characteristic general introduction

In order to solve a difficult problem for metering level liquid level automatic Observation, inventor is through a large amount of theoretical research and experimental demonstration, innovation " electromagnetism scale liquid level gauge ".

Electromagnetism scale liquid level gauge has fundamentally solved the measuring accuracy problem of other electrical measurement liquid level gauges, and maximum absolute error is 1.25 millimeters, no matter range is much, does not have cumulative errors, and does not need throughout one's life calibration.Electromagnetism scale liquid level gauge, except keeping whole technical characteristics of past artificial observation rule, can also directly be read liquid level elevation, without the quantity of the rule by liquid level, calculates liquid level elevation.

Electromagnetism scale liquid level gauge can be set up pedestal in reservoir area or bottom riverbed and install, and also can adopt trestle or hanging stick mode to install, and installation is not affected by liquid level period.The every segment length of electromagnetism scale liquid level gauge is 50 centimetres, configure dedicated jointing, and maximum range reaches 100 meters, has thoroughly solved the limit of range of mangneto formula liquid level gauge.Configuration stainless steel water-tight sleeve pipe can be installed by step type as common enamel water gauge, adopts cable to connect between each section.

(2) principle of electromagnetism scale liquid level gauge and structure

Hall switch forms electromagnetic switch signal system together with suspension electromagnetism ring, be usually used in liquid level limit switch device, wherein Hall switch is used as electric signal scale mark, suspension electromagnetism ring is used as pointer, theoretically, one group of Hall switch is equidistantly arranged, and spacing is less than metering during resolution, can obtain an electric signal rule.But, if when the spacing between Hall switch is less than the effective width in pointer magnetic field, will there are the corresponding a plurality of scale states (being that scale mark is not unique) of same pointer position, therefore, require magnetic field width must be less than the spacing between Hall switch.At this moment will produce a new problem, among pointer is positioned at two Hall switch between time, stateless output in whole Hall switch array.Control break electromagnetic field width in the present invention, makes magnetic field, optional position width cover unique Hall switch assembled state.Then it is carried out to configuration coding, obtain unique position encoded value, realized electrical measurement and the digital signal output of liquid level, thereby invented electromagnetism scale liquid level gauge.

Electromagnetism scale liquid level gauge is comprised of four parts such as Hall switch array, reading demonstration and communication module, electromagnetism ring liquid level pointer, seal protection sleeve pipes.Structural drawing is as Fig. 1: as shown in electromagnetism scale liquid level gauge structural drawing.

Fig. 1 is electromagnetism scale-type liquid level gauge structural drawing.

Fig. 2 is Sealed casing pipe structural drawing.

Communication and display module have guaranteed that this equipment possesses automatic data collection and two kinds of functions of artificial on-the-spot reading simultaneously.In order to facilitate operator on duty's reading at night, display module has adopted light emitting diode matrix demonstration, apart from 400 meters, water gauge, can clearly read current liquid level and unrestrained high data, effectively reduces operator on duty's working strength.Communications portion provides standard RS-485 interface, and data stipulations are Modbus, can realize seamless access with current general all PLC systems.In communication module, also comprise mobile communications network interface, can realize SMS report liquid level and unrestrained high data.

(3) benefit of electromagnetism scale liquid level gauge

1) electromagnetism scale liquid level gauge thoroughly changed current electrical measurement class liquid level gauge can only be as the situation of auxiliary watch-dog, it retains and has promoted passes by the complete characteristic of rule.

2), during for hydrologic observation, catchment position and unrestrained height are observed in one, greatly reduce construction cost.

3) electromagnetism scale liquid level gauge range is large, and in full range, maximum absolute error is less than 1.25 millimeters, without cumulative errors, meets the demand of any Water Under literary composition observation completely.

4) possess three kinds of reading modes: artificial remote directly reading, automation collection data, SMS message reading.

5) system power dissipation is low, is applicable to powered battery and solar powered.

6) transportation and easy for installation, can set up pedestal in reservoir area or bottom riverbed and install, and also can adopt trestle or hanging stick mode to install.

7) configure the electromagnetism ring of two different buoyancy, can measure water level and the oil level of large-scale petroleum tank simultaneously, can be used for crude oil transaction metering.

8) can be used for horizontal shift and the sedimentation automatic measurement of native stone dam.

9) this equipment anti-vibration, antisurge ability are strong, sound construction, stable performance, long service life.

Claims

1. the object of this invention is to provide a kind of metering level level measuring instrument (system) that is applicable to use in physical environment and tank, the gordian technique of this patent product is: using Hall switch array as electric signal scale, employing is suspended between two kinds of liquid surfaces or the electromagnetism ring of liquid surface is reading pointer, by control break electromagnetic field width, make magnetic field, optional position width cover unique Hall switch assembled state.Detect the state value of Hall switch array and carry out configuration coding, obtaining current pointer position, thereby realize level gauging.

2. the feature based on patent 1 is: set up the corresponding relation of Hall switch physical location and liquid surface, and Hall switch array induction liquid level position, by configuration, encoding to calculate obtains level value.It is different from any in existing two class level gauging technology, existing two classes respectively: 1) be pressure measurement class, the principle of this quasi-instrument is to calculate liquid level by measuring liquid pressure; 2) survey the time difference (phase differential) class, measure sound wave, lightwave signal is poor two-way time to liquid level from reference point, by the time difference and speed, calculates distance, thus calculating liquid level; Or measure sound wave, lightwave signal and from reference point to liquid level, come and go phase differential, utilize wavelength (phase place) and the corresponding relation of distance to calculate liquid level.

Product key technical feature based on patent 1 is as follows:

(1) feature in measuring principle

1) with the scale mark of the simulation of Hall switch array and replacement rule, realize graph line to the conversion of electric signal (logic scale mark); Electromagnetism fourth finger pin is suspended on the interface of liquid surface or two kinds of different liquids, and control break electromagnetic field width makes magnetic field, optional position width cover unique Hall switch assembled state;

2) set up the corresponding relation of Hall switch physical location and liquid surface position, configuration scrambler is encoded to Hall switch combinations of states, replaces artificial visually examine's identification, realizes liquid level digital measurement and (can be described as: configuration coding techniques);

3) between electromagnetism fourth finger pin and Hall switch array, both without circuit, be connected also machinery-free and connect, this metering system is a kind of non-contact measurement.

(2) feature on apparatus structure

1) this patent product is comprised of Hall switch array, electromagnetism fourth finger pin, assembled state scrambler, data management and communication unit and 5 parts of tool housing;

2) in Hall switch array, element physical location equal intervals is arranged, and the distance between two Hall switch is less than or equal to 2 times of resolving powers of instrument;

3) the effective magnetic field width of electromagnetism fourth finger pin changes according to the integral multiple of resolution;

4) unit electricity chi length is 1 meter or 4 feet, and electric chi number equals the target range of electromagnetism scale liquid level gauge.

3. protection domain

(1) liquid level based on above-mentioned thinking (water level) measurement product should be within protection domain of the present invention.

(2) horizontal shift based on above-mentioned thinking and perpendicular displacement measurement products should be within protection scope of the present invention.