CN202075016U - Self-correcting external-measurement liquid level switch measurement system - Google Patents
Self-correcting external-measurement liquid level switch measurement system Download PDFInfo
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- CN202075016U CN202075016U CN2011201605357U CN201120160535U CN202075016U CN 202075016 U CN202075016 U CN 202075016U CN 2011201605357 U CN2011201605357 U CN 2011201605357U CN 201120160535 U CN201120160535 U CN 201120160535U CN 202075016 U CN202075016 U CN 202075016U
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- measuring head
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Abstract
The utility model discloses a self-correcting external-measurement liquid level switch measurement system, which comprises an external-measurement liquid level switch mainframe, a main measurement head and an auxiliary measurement head, wherein both the main measurement head and the auxiliary measurement head are absorbed at the outer wall of a container, the center of the pitch of the main measurement head and the auxiliary measurement head aligns to a liquid level monitoring point, the main measurement head and the auxiliary measurement head are simultaneously connected with the external-measurement liquid level switch mainframe, and the main measurement head is positioned above the auxiliary measurement head. The self-correcting external-measurement liquid level switch measurement system disclosed by the utility model solves the problems that the existing liquid level switch which is externally arranged has high misoperation rate, poor working stability and reliability, needs personnel to periodically demarcate and adjust in the use at a site, and has large installation and debugging working quantity and low efficiency.
Description
Technical field:
The utility model belongs to the level gauging field in the industrial automation instrument, relates to a kind of level switch system, and the level switch measuring system is surveyed in especially a kind of self-correcting outward.
Background technology:
At present, the level switch in that install the container outside has external labeling type level switch, external level switch etc.Its principle of work is, locate to install and measure head in the monitoring point that the container side wall outside needs to detect liquid level, measuring head is launched ultrasound wave in chamber wall, can come back reflective repeatedly to form the remained shock signal after ultrasound wave enters in the chamber wall inside between the inside and outside surface of chamber wall.Ultrasound wave enters the transmission coefficient K of liquid in the chamber wall
LiquidThe acoustic impedance R of=liquid
LiquidThe acoustic impedance R of/chamber wall
WallR wherein
Liquid=fluid density ρ
Liquid* liquid acoustic velocity V
Liquid=1 (gram/cubic centimetre) * 1600 (meter per second)=1600.Ultrasound wave enters the transmission coefficient K of gas in the chamber wall
GasThe acoustic impedance R of=gas
GasThe acoustic impedance R of/chamber wall
WallR wherein
Gas=gas density ρ
Gas* gas velocity of sound V
Gas≌ 0 (gram/cubic centimetre) * 340 (meter per second)=0.Hence one can see that ultrasound wave enters the transmission coefficient K of liquid in the chamber wall
LiquidEnter the transmission coefficient K of air in much larger than ultrasound wave from chamber wall
GasSo when liquid level is lower than the monitoring point in the container, because transmission coefficient K
Gas≌ 0, and ultrasound wave comes the number of times meeting of back reflective many between the inside and outside surface of chamber wall, and energy loss can be slow, and the number of remained shock signal wave can be many.When liquid level is higher than the monitoring point in the container, because transmission coefficient K
Liquid=1600, ultrasound wave comes the number of times of back reflective can be fewer between the inside and outside surface of chamber wall, and energy loss can be than comparatively fast, and the number of remained shock signal wave can be fewer.
In the prior art, the measuring method of the level switch of installing in container outside is to detect the remained shock signal of ultrasound wave in chamber wall inside, and the amplitude of emission ultrasonic signal remained shock signal after a period of time or amplitude (are called for short signal value V to the integrated value of time
Letter) with amplitude of setting or amplitude time integral value (is called for short setting value V
If) compare, as signal value V
LetterGreater than setting value V
IfThe time judge that liquid level is lower than the monitoring point, as signal value V
LetterLess than setting value V
IfThe time judge that liquid level is higher than the monitoring point.
But, make back signal value V is installed because the coupling layer of adhesion layer, fluid temperature, container outer wall and the measuring head of container inner wall surface retrogradation can change in time
LetterChange greatly, instability, malfunction rate height, job stability and reliability are very poor.And, because the amplitude of remained shock signal or amplitude can be different because of tank skin material, thickness, liquid component and the temperature of each container to the integrated value of time, the V on the different vessels
LetterDifference is very big, need be for the artificial on-site proving setting value of each container V
If, the Installation and Debugging workload is very big, and efficient is low, is about 2-6 month serviceable life, causes in fact and can not use for a long time.
The utility model content:
The level switch measuring system is surveyed in self-correcting of the present utility model outward and measuring method has solved the level switch malfunction rate height that present outside installs and measures, job stability and poor reliability and use at the scene in need artificial periodic calibrating adjustment, the Installation and Debugging workload is very big, inefficient problem.
The purpose of this utility model is to overcome the shortcoming of above-mentioned prior art, provide a kind of self-correcting to survey the level switch measuring system outward, comprise outer main measuring head and the secondary measuring head of surveying the level switch main frame, being arranged on the chamber wall outside, the spacing centrally aligned level monitoring point of described main measuring head and secondary measuring head; Described main measuring head all is connected with outer survey level switch main frame with secondary measuring head simultaneously, and main measuring head is positioned at secondary measuring head top; The spacing at described main measuring head center and secondary measuring head center is h, and main measuring head center and secondary measuring head center equate with the distance of level monitoring point, all be h/2.
The spacing at described main measuring head center and secondary measuring head center is h, and main measuring head center and secondary measuring head center equate with the distance of level monitoring point, all be h/2.
The scope of described h is 10-500mm.
Described main measuring head and secondary measuring head are the measuring heads of same type.
Described container is ball-type jar, horizontal tank, vertical tank or process jar.
When described container was the ferromagnetism container, main measuring head and secondary measuring head adopted magnetic force directly to be adsorbed on the ferromagnetism chamber wall outside.
When described container is the nonferromagnetic container, the bonding chamber wall outside that is fitted in of main measuring head and secondary measuring head, perhaps main measuring head and secondary measuring head are fixed on the chamber wall outside by Connection Block.
Described main measuring head and secondary measuring head constitute a self-correcting measuring head group; Described system comprises several self-correcting measuring head groups.
Described system is used for measuring the liquid level of the liquid that is stored in ball-type jar, horizontal tank, vertical tank or process jar.
The advantage that level switch measuring system and measuring method thereof are surveyed in self-correcting of the present utility model outward is, the signal sets value need not manually be set, but store the signal value data that youngest liquid level is lower than and has arrived and covered the monitoring point, automatically calculate the signal sets value and judge fluid level condition with youngest data, realize full automatic " foolproof " installation.
Description of drawings:
Fig. 1 surveys level switch measuring system structural representation outward for self-correcting of the present utility model;
Fig. 2 is V of the present utility model
Letter is mainAnd V
Letter is secondaryOne-shot measurement curve map with actual liquid level L;
Fig. 3 is V of the present utility model
The postman~L curve map;
Wherein: 1 is container; 2 is the outer level switch main frame of surveying; 3 is main measuring head; 4 is secondary measuring head.
Embodiment:
Below in conjunction with accompanying drawing the utility model is done and to be described in further detail:
Referring to Fig. 1, Fig. 2 and Fig. 3, the level switch measuring system is surveyed in self-correcting of the present utility model outward, comprise outer main measuring head and the secondary measuring head of surveying the level switch main frame, being arranged on the chamber wall outside, the spacing centrally aligned level monitoring point of described main measuring head and secondary measuring head; Described main measuring head all is connected with outer survey level switch main frame with secondary measuring head simultaneously, and main measuring head is positioned at secondary measuring head top; The spacing at described main measuring head center and secondary measuring head center is h, and main measuring head center and secondary measuring head center equate with the distance of level monitoring point, all be h/2.
Self-correcting of the present utility model is surveyed the level switch measuring method outward and is comprised:
1, surveys level switch main frame, main measuring head and secondary measuring head outward; The outer level switch main frame of surveying is connected with main measuring head and secondary measuring head; Two measuring head performances are identical, are installed on the outside surface of same sidewall of same container, and the center of two measuring heads is at a distance of h; Main measuring head is installed in than level monitoring and puts high h/2 part, and secondary measuring head is installed in than the low h/2 part of level monitoring point, and perhaps secondary measuring head is installed in the place, monitoring point;
Signal value V with main measuring head
Letter is mainSubtract the signal value V of secondary measuring head
Letter is secondarySignal value V as the combination of self-correcting measuring head
The postman, i.e. V
The postman=V
Letter is main-V
Letter is secondaryV
The postman~L (liquid level) curve is a pulse form curve that raises up between main measuring head, secondary measuring head installation place, V when liquid level L is lower than secondary measuring head or is higher than main measuring head
The postman~L is the straight line of level basically, when liquid level rises to V when covering secondary measuring head
The postman~L curve jumps to maximal value suddenly, when liquid level continues to rise to V when covering main measuring head
The postman~L curve jumps to the horizontal line position suddenly.
When liquid level is passed through main measuring head and secondary measuring head successively from the downward reduction of height, V
The postmanCurve shape when~L curve rises with liquid level is the same.The signal value of the feature of curve and two measuring heads can judge easily that liquid level is lower than the monitoring point, is higher than the monitoring point or has arrived the monitoring point thus.
2, the self-correcting of the present utility model main points of surveying level switch measuring system and measuring method thereof outward also are, the signal sets value need not manually be set, but the most recent liquid level of storage is lower than and has arrived and covered the signal value data of monitoring point, calculates the signal sets value automatically and judges fluid level condition with youngest data.Realize full automatic " foolproof " installation.
Can be explanatorily more specifically clearer in conjunction with following example, main measuring head setting height(from bottom) is: H
High=1540 millimeters, secondary measuring head setting height(from bottom) is H
Low=1440 millimeters, two measuring heads distance is 100 millimeters.
Accompanying drawing 1. is main measuring head signal values with the curve of liquid level change and the secondary measuring head signal value curve with liquid level change.Can see by figure, originally with a measuring head, the signal value data that records when for example judging liquid level, liquid level with main measuring head be lower than the measuring head position for example 1520 millimeters the time signal value be 3220, when liquid level be higher than the measuring head position for example 1580 millimeters the time signal value be 2870, so manually set V
If it is high=(3220+2870)/2=3045.
As signal value V
Letter is main<V
If it is highJust judged that liquid level has reached the monitoring point, should send alerting signal at=3045 o'clock.If but judge that with the signal value data that the secondary measuring head that is installed on the same container records signal value only reaches 2930<V when finding but that liquid level is lower than the monitoring point
If it is high=3045, signal value just was lower than 3045 when promptly liquid level was far below the monitoring point, will wrongly judge that liquid level has reached the monitoring point, and false alarm takes place.
Experiment find same monitoring point measured value also can be because of liquid component, temperature and chamber wall surface liquid wall built-up, solidify and the variation of measuring head coupling etc. and changing in time, inconsequent is so can't correctly stably judge whether liquid level has exceeded the monitoring point according to the changeless setting value of the artificial setting of the measured value in past.
Main thought of the present utility model is based on:
1, be installed near the same container same position main measuring head and secondary measuring head with installation site and time take place above-mentioned because liquid component, temperature and chamber wall surface liquid wall built-up, solidify and signal value that variations such as measuring head coupling causes to change be approximately uniform, so the signal difference of main measuring head and secondary measuring head is subjected to the influence of these co-variations interference very little.Common mode interference has been offset in other words, and the interference of output has just reduced greatly.
2, the signal difference of main measuring head and secondary measuring head is that the liquid that records the most at no distant date according to storage is lower than, reaches, is higher than the timely data that youngest data computation that the signal value of monitoring point brings in constant renewal in is come out, and the setting value of the multiple measurement head that calculates in view of the above is to upgrade in time accurately.
Accompanying drawing 2. is the curve of the signal difference of main measuring head signal value and secondary measuring head signal value with liquid level change, i.e. V
The postman~L curve, V here
The postman=(V
Letter is main-V
Letter is secondary).
By accompanying drawing 2 as can be known, when liquid level is lower than 1440 millimeters of secondary measuring head mounting points or be higher than 1540 millimeters of main measuring head mounting points, V
The postman<500, V when liquid level is between main measuring head, secondary measuring head mounting points
The postman>800.So can be defined as its intermediate value to the setting value of main measuring head, secondary measuring head, promptly set V
If group=(500+800)/2=650.
Work as V
The postman>V
If group, and V in the accompanying drawing 1
Letter is secondary<V
If it is low, send the alerting signal that liquid level arrives the monitoring point at=2665 o'clock.
Work as V
The postman<650, and V
Letter is secondary>V
If it is lowJudged that liquid level was lower than 1440 millimeters of low level monitoring points at=2665 o'clock.Work as V
The postman<650, and V
Letter is main<V
If it is highJudged that liquid level was higher than 1540 millimeters of high-order monitoring points at=3035 o'clock.
The signal difference V of main measuring head signal value, secondary measuring head signal value
The postman=(V
Letter is main-V
Letter Secondary) be by main measuring head V
Letter is main, secondary measuring head signal value V
Letter is secondarySubtract each other generation, the co-variation that signal value takes place in time can not influence main measuring head, secondary measuring head signal difference V
The postmanSo can judge stably accurately whether liquid level has reached the monitoring point height.
Main measuring head in the utility model and secondary measuring head can make conventional ultrasonic probe, and resulting signal value can be to adopt the resulting normal signal value of ultrasonic probe.
Above content is to further describing that the utility model is done in conjunction with concrete preferred implementation; can not assert that embodiment of the present utility model only limits to this; for the utility model person of an ordinary skill in the technical field; under the prerequisite that does not break away from the utility model design; can also make some simple deduction or replace, all should be considered as belonging to the utility model and determine scope of patent protection by claims of being submitted to.
Claims (8)
1. the level switch measuring system is surveyed in a self-correcting outward, comprises outer main measuring head and the secondary measuring head of surveying the level switch main frame, being arranged on the chamber wall outside, it is characterized in that: the spacing centrally aligned level monitoring point of described main measuring head and secondary measuring head; Described main measuring head all is connected with outer survey level switch main frame with secondary measuring head simultaneously, and main measuring head is positioned at secondary measuring head top; The spacing at described main measuring head center and secondary measuring head center is h, and main measuring head center and secondary measuring head center equate with the distance of level monitoring point, all be h/2.
2. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: the scope of described h is 10-500mm.
3. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: described main measuring head and secondary measuring head are the measuring heads of same type.
4. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: described container is ball-type jar, horizontal tank, vertical tank or process jar.
5. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: when described container was the ferromagnetism container, main measuring head and secondary measuring head adopted magnetic force directly to be adsorbed on the ferromagnetism chamber wall outside.
6. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: when described container is the nonferromagnetic container, the bonding chamber wall outside that is fitted in of main measuring head and secondary measuring head, perhaps main measuring head and secondary measuring head are fixed on the chamber wall outside by Connection Block.
7. survey the level switch measuring system outward as self-correcting as described in the claim 6, it is characterized in that: described Connection Block is welded on the chamber wall outside, and main measuring head and secondary measuring head are fixed between the chamber wall outside and the Connection Block.
8. the level switch measuring system is surveyed in self-correcting outward according to claim 1, it is characterized in that: described main measuring head and secondary measuring head constitute a self-correcting measuring head group; Described system comprises several self-correcting measuring head groups.
Priority Applications (1)
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CN2011201605357U CN202075016U (en) | 2011-05-18 | 2011-05-18 | Self-correcting external-measurement liquid level switch measurement system |
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CN2011201605357U CN202075016U (en) | 2011-05-18 | 2011-05-18 | Self-correcting external-measurement liquid level switch measurement system |
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CN202075016U true CN202075016U (en) | 2011-12-14 |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102297715A (en) * | 2011-05-18 | 2011-12-28 | 西安定华电子有限公司 | Self-correcting measurement system and method of outside measurement liquid level switch |
CN104615023A (en) * | 2014-12-31 | 2015-05-13 | 重庆川仪自动化股份有限公司 | Intelligent setting method for level switch |
CN112729470A (en) * | 2020-12-28 | 2021-04-30 | 西安定华电子股份有限公司 | Method for determining reflecting surface of steering gear and focusing steering gear of external liquid level meter |
-
2011
- 2011-05-18 CN CN2011201605357U patent/CN202075016U/en not_active Expired - Lifetime
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102297715A (en) * | 2011-05-18 | 2011-12-28 | 西安定华电子有限公司 | Self-correcting measurement system and method of outside measurement liquid level switch |
CN102297715B (en) * | 2011-05-18 | 2012-09-19 | 西安定华电子有限公司 | Self-correcting measurement system and method of outside measurement liquid level switch |
CN104615023A (en) * | 2014-12-31 | 2015-05-13 | 重庆川仪自动化股份有限公司 | Intelligent setting method for level switch |
CN104615023B (en) * | 2014-12-31 | 2018-04-27 | 重庆川仪自动化股份有限公司 | Intelligent setting method for level switch |
CN112729470A (en) * | 2020-12-28 | 2021-04-30 | 西安定华电子股份有限公司 | Method for determining reflecting surface of steering gear and focusing steering gear of external liquid level meter |
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Legal Events
Date | Code | Title | Description |
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C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
C56 | Change in the name or address of the patentee | ||
CP01 | Change in the name or title of a patent holder |
Address after: 710065 Shaanxi city of Xi'an province high tech Zone Guangde road F2B-5 Patentee after: Xi'an electronic Limited by Share Ltd Address before: 710065 Shaanxi city of Xi'an province high tech Zone Guangde road F2B-5 Patentee before: Xi'an Dinghua Electronics Co., Ltd. |
|
CX01 | Expiry of patent term |
Granted publication date: 20111214 |
|
CX01 | Expiry of patent term |