CN111060178A - Method for acquiring liquid level in cabin - Google Patents
Method for acquiring liquid level in cabin Download PDFInfo
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- CN111060178A CN111060178A CN201911406240.0A CN201911406240A CN111060178A CN 111060178 A CN111060178 A CN 111060178A CN 201911406240 A CN201911406240 A CN 201911406240A CN 111060178 A CN111060178 A CN 111060178A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
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Abstract
The invention discloses a method for acquiring liquid level in a cabin, which comprises the following steps: step 1: two pressure sensors are arranged at the bottom of the cabin to be measured at intervals from bottom to top; step 2: calculating the density of a medium to be measured between the two pressure sensors in the cabin to be measured according to the pressure difference of the two pressure sensors and the installation position drop; and step 3: calculating the height of the medium to be measured according to the real-time density acquired in the step 2 and one pressure value of the two pressure sensors; the invention avoids the use of a sensor, and can not obtain the density of the medium to be measured in real time when backpressure occurs due to the fact that the fixed density of the medium to be measured is set, and the deviation of a calculation result is large.
Description
Technical Field
The invention relates to the technical field of cabin liquid level acquisition, in particular to a method for acquiring liquid level in a cabin with back pressure.
Background
With the development of the shipping industry and the improvement of the degree of automation of ships, liquid level measurement systems are widely used, and reliable measurement makes the liquid level measurement of the ship tank including ballast water very important for a liquid level remote measurement system, and especially stable measurement of draft is very important for the safety of ships. Due to the fact that the ship structures are different, the cabins formed by different ship structures are used, different liquid level calculation methods are adopted, the traditional cabin liquid level calculation method mainly depends on manual setting of density of media and pressure measured by a sensor, and liquid level height is calculated by manually modifying density of the measured media under different conditions. This method is not suitable for a chamber containing back pressure, and when the liquid level is higher than the air permeability tube, air back pressure is formed at the top of the chamber, which changes the density of the measured medium, and once the density is changed, the density is in error with the density of the medium set manually, so that the measured liquid level data is unreliable. The problem is not solved well for a long time, and the reliability of the liquid level measuring system is directly influenced.
Disclosure of Invention
The invention provides a method for acquiring liquid level in a cabin, which aims to solve the technical problem that in the prior art, the measurement precision is reduced after the density of a medium to be measured in the cabin containing back pressure is changed.
The invention provides a method for acquiring liquid level in a cabin, which comprises the following steps:
step 1: two pressure sensors are arranged at the bottom of the cabin to be measured at intervals from bottom to top;
step 2: calculating the density of a medium to be measured between the two pressure sensors in the cabin to be measured according to the pressure difference of the two pressure sensors and the installation position drop;
and step 3: and (3) calculating the height of the medium to be measured according to the real-time density acquired in the step (2) and one pressure value of the two pressure sensors.
Further, in the step 2, a formula for calculating the density of the medium to be measured between the two pressure sensors in the chamber to be measured according to the pressure difference between the two pressure sensors and the installation position drop is as follows:
Δρ＝ΔP/(g*ΔH)
wherein: "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity.
Further, in the step 3, according to the real-time density obtained in the step 2 and one pressure value of the two pressure sensors, a formula for calculating the height of the medium to be measured is as follows:
H＝P/(Δρ*g)＝P/((ΔP/g*ΔH)*g)＝(P*ΔH)/ΔP
wherein: "H" is the height of the medium to be measured; "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "P" is a pressure value of one of the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity.
Further, in the step 3, the height of the medium to be measured is calculated according to the real-time density obtained in the step 2 and the pressure value of the pressure sensor with the installation position under.
Further, the height difference of the two pressure sensors is 1 meter.
Furthermore, the gravity acceleration "g" is obtained according to the longitude and latitude.
The invention has the beneficial effects that:
according to the invention, two pressure sensors are arranged at the bottom of the cabin, the relation among pressure, density and height is utilized, the real-time density of the medium to be measured at the current position is reversely deduced through pressure difference and height difference, and finally the height of the medium to be measured is calculated according to the pressure value obtained by one pressure sensor and the obtained real-time density, so that the situation that when back pressure occurs due to the fact that one sensor is only set, the density of the medium to be measured cannot be obtained in real time, and the deviation of the calculation result is large is avoided.
The invention avoids manual setting of medium density, and can adapt to the situation that the medium density cannot be accurately known when the mixture is added into the cabin.
Drawings
The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:
FIG. 1 is a schematic diagram of the installation position of a pressure sensor in a method for acquiring liquid level in a cabin according to the present invention;
FIG. 2 is a schematic diagram of a conventional apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a method for acquiring liquid level in a cabin, which is characterized in that according to a relation formula among pressure, density and height, the actual density of a medium between two pressure sensors is acquired by installing two pressure sensors with height drop, the actual height is reversely deduced through the actual density without manually setting the density, and the method comprises the following steps:
step 1: as shown in fig. 1, two pressure sensors are arranged at the bottom of a cabin to be measured at intervals from bottom to top, the two pressure sensors are arranged on a vertical line, the pressure sensor close to the bottom is a pressure sensor 1, and a pressure sensor 2 is arranged above the pressure sensor 1 and is a pressure sensor 2; the distance between the two pressure sensors is preferably 1 meter;
step 2: acquiring a pressure value P1 of a pressure sensor 1 and a pressure value P2 of a pressure sensor 2; calculating the difference value delta P between P1 and P2;
acquiring the installation height H1 of the No. 1 pressure sensor 1 and the installation height H2 of the No. 2 pressure sensor 2; calculating the difference Δ H between H1 and H2;
according to the relation formula among pressure intensity, height, density and gravity acceleration:
Ρ＝ρ*g*H
the density 'delta rho' of the medium to be measured between the two pressure sensors can be obtained by substituting the delta P, the delta H and the gravity acceleration g into the formula, and the specific formula is as follows:
Δρ＝ΔP/(g*ΔH)
wherein: "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity;
and step 3: calculating the height of the medium to be measured according to the real-time density delta rho obtained in the step 2 and the pressure value of the pressure sensor 1 No. 1, wherein the formula is as follows:
H＝P1/(Δρ*g)＝P1/((ΔP/g*ΔH)*g)＝(P1*ΔH)/ΔP
wherein: "H" is the height of the medium to be measured; "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "P" is a pressure value of one of the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity.
Because the positions of the ship for navigation are different, different gravity accelerations exist in different longitudes and latitudes on the earth, and in order to improve the calculation accuracy of the method, the gravity acceleration 'g' is obtained according to the longitudes and latitudes.
As shown in fig. 2, the No. 3 pressure sensor 3 is installed in the air at the top of the cabin, and is not in contact with the medium to be measured below, and the obtained pressure value is the pressure of the air.
The following table 1 shows the comparison between the height obtained by the method of the present invention and the height obtained by the existing method when the cabin is filled with pure water at different heights and the height difference between the pressure sensor 1 and the pressure sensor 2 is 1 meter:
| measuring | Data | 1 | |
|
|
| No. 1 pressure sensor | Water (W) | 0.0490 MPa | 0.1078 MPa | 0.1470 MPa | |
| No. 2 pressure sensor | Water (W) | 0.0390 MPa | 0.0978 MPa | 0.1370 MPa | |
| No. 3 pressure sensor | Water/air | 1063.21 Pa | 2016.16 Pa | 3236.51 Pa | |
| Actual height | 5 m | 11 m | 15 m | ||
| Existing calculation methods | 4.79 m | 10.69 m | 14.66 m | ||
| Error of the existing method | 0.21 m | 0.31 m | 0.34 m | ||
| The invention discloses a computing method | 4.9 m | 10.8 m | 14.7 m | ||
| Error of the method of the invention | 0.1 m | 0.2 m | 0.3 m |
TABLE 1
As can be seen from table 1, the height obtained by the obtaining method of the present invention is more accurate than the height obtained by the existing method.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (6)
1. A method of obtaining a liquid level in a chamber, comprising the steps of:
step 1: two pressure sensors are arranged at the bottom of the cabin to be measured at intervals from bottom to top;
step 2: calculating the density of a medium to be measured between the two pressure sensors in the cabin to be measured according to the pressure difference of the two pressure sensors and the installation position drop;
and step 3: and (3) calculating the height of the medium to be measured according to the real-time density acquired in the step (2) and one pressure value of the two pressure sensors.
2. The method for acquiring the liquid level in the cabin according to claim 1, wherein the formula for calculating the density of the medium to be measured between the two pressure sensors in the cabin to be measured according to the pressure difference between the two pressure sensors and the installation position drop in the step 2 is as follows:
Δρ＝ΔP/(g*ΔH)
wherein: "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity.
3. The method for acquiring the liquid level in the cabin according to claim 2, wherein the formula for calculating the height of the medium to be measured in step 3 according to the real-time density acquired in step 2 and one pressure value of the two pressure sensors is as follows:
H＝P/(Δρ*g)＝P/((ΔP/g*ΔH)*g)＝(P*ΔH)/ΔP
wherein: "H" is the height of the medium to be measured; "Δ ρ" is the density of the medium to be measured between the two pressure sensors; "P" is a pressure value of one of the two pressure sensors; "Δ P" is the pressure difference between the two pressure sensors; "Δ H" is the difference in mounting position height between the two pressure sensors; "g" is the acceleration of gravity.
4. A method for obtaining the liquid level in the cabin according to any one of claims 1 to 3, wherein in the step 3, the height of the medium to be measured is calculated according to the real-time density obtained in the step 2 and the pressure value of the pressure sensor under the installation position.
5. The method for acquiring a liquid level in a cabin according to claim 1, wherein the difference in height between the two pressure sensors is 1 m.
6. The method of claim 1, wherein the acceleration "g" is obtained by obtaining the acceleration "g" according to the longitude and latitude of the ship.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911406240.0A CN111060178A (en) | 2019-12-31 | 2019-12-31 | Method for acquiring liquid level in cabin |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911406240.0A CN111060178A (en) | 2019-12-31 | 2019-12-31 | Method for acquiring liquid level in cabin |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6282953B1 (en) * | 2000-05-12 | 2001-09-04 | Eaton Corporation | Solid state fuel level sensing |
| CN105241788A (en) * | 2015-09-14 | 2016-01-13 | 天津二十冶建设有限公司 | Convenient industrial canning liquid density measurement method |
| CN205102882U (en) * | 2015-11-18 | 2016-03-23 | 四川省银河化学股份有限公司 | Liquid level measuring apparatus |
| CN105466521A (en) * | 2016-01-11 | 2016-04-06 | 苏州鑫瑞电气有限公司 | Method for measuring liquid level of liquid in container |
| CN107270993A (en) * | 2017-06-30 | 2017-10-20 | 西京学院 | It is a kind of while measuring the device of propellant liquid level and density |
| CN109443481A (en) * | 2018-12-22 | 2019-03-08 | 中铁工程装备集团有限公司 | A kind of closed pressure vessel measuring device and level measuring method |
-
2019
- 2019-12-31 CN CN201911406240.0A patent/CN111060178A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6282953B1 (en) * | 2000-05-12 | 2001-09-04 | Eaton Corporation | Solid state fuel level sensing |
| CN105241788A (en) * | 2015-09-14 | 2016-01-13 | 天津二十冶建设有限公司 | Convenient industrial canning liquid density measurement method |
| CN205102882U (en) * | 2015-11-18 | 2016-03-23 | 四川省银河化学股份有限公司 | Liquid level measuring apparatus |
| CN105466521A (en) * | 2016-01-11 | 2016-04-06 | 苏州鑫瑞电气有限公司 | Method for measuring liquid level of liquid in container |
| CN107270993A (en) * | 2017-06-30 | 2017-10-20 | 西京学院 | It is a kind of while measuring the device of propellant liquid level and density |
| CN109443481A (en) * | 2018-12-22 | 2019-03-08 | 中铁工程装备集团有限公司 | A kind of closed pressure vessel measuring device and level measuring method |
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Application publication date: 20200424 |