LINDGREN OESTEN (SE)
| US4064752A | 1977-12-27 | |||
| US4665746A | 1987-05-19 | |||
| US5347863A | 1994-09-20 | |||
| US4526035A | 1985-07-02 | |||
| US4299116A | 1981-11-10 | |||
| US4669309A | 1987-06-02 |
| 1. | A method for measuring the volume ol a medium in a tank containing two liquids of different specific weight, two essentially vertical pipes, w hich are open at then bottoms and have connection with a gasmedium source, extending dow nwards in the tank in question and being filled with the tank media, the highest medium lev el m the tank being denoted h|. the end level for the first pipe with lv and the end level for the second pipe with lv,. and hi lying higher than lv. which lies higher than lv,. c h a r a c t e r i z e d by the combination ol the following steps: A gasmedium of a certain pressure is allowed to stream into the first vertical pipe (13a) with the end level h via a main line (6) so that the tank medium disappears out ot the pipe, whereafter the connection to the gasmedium source is shut off. The pressure in the vertical pipe ( 13a). which is directly dependent upon the size o! the difference between the medium levels hi and lv. is sensed by a pressure sensoi (33) and is measured by a measuπng unit (30). whereafter a computer, connected to the measuπng unit. calculates the volume of the medium in the tank ( 19) between the levels hi and lv on basis ol the measured pressure, the volume of the tank and the specific weight of the tank medium. The gasmedium is thereafter allowed to stream into the second, vertical pipe ( 1 a) with the end level h3. so that the tank medium disappears out of the pipe, whereafter the connection to the gasmedium source is shut off. The pressure in the second, vertical pipe ( 14a). which is directly dependent upon the size of the difference between the medium levels hi and lv,. is sensed by the pressure sensor (33). which value is compaired with a predetermined value, which should be valid ii the liquid of the tank (19) would be one and the same, and that the size of the difference between the measured pressure and the predetermined one indicates the volume size ot the second medium; The integrated computer (35) calculates the volume of the second medium between the levels h and h3 on basis of the measured pressure and the specific weight of the second tank medium. |
| 2. | An apparatus for measuπng the volume of a medium in a plurality ot tanks. connected in parallel, a main conduit (6) for a gasmedium being connected with a gasmedium source ( 1) via a first valve means (4). c h a r a c t e r i z e d by the combination ot the following features. Each tank (1923) is connected with the main conduit (6) of the gasmedium via a conduit (1418) and a distribution valve means (817), Each conduit ( 1418) to the tank ( 1923) is in the form ol a pipe extending essentially vertically through the same down to its bottom portion, the pipe ( 14a 18a) being open at its bottom so that the tank medium can get up into the pipe, A central pressure sensor (33) is connected to main conduit (6) ot the gas medium at a portion of the same between the first valve means (4) and the distribution vah e means ( 8 12). connected in parallel, which pressure sensor accordingly can sense the pressure in the different tanks (1923), The pressure sensoi (33) is connected with a measuπng unit (30) which in us turn is connected with a computer (35) which on basis of the pressure measured bv the measuring unit, the volume of the tank and the specific weight of the tank medium calculates the volume of the tank medium . |
| 3. | An apparatus for measuring the volume of two media in a tank which media hav e a different specific weight, a main conduit of gas medium being connected to a gasmedium source via a first valve means, c h a r a c t e r i z e d bv the combination of the following features The tank ( 19) is connected with the main conduit (6) ot the gasmedium v ia two conduits (13. 14) and two distribution valve means (7, 8), Each conduit ( 13. 14) is in the form of a pipe extending essentialh v erticallv downwards in the tank 19). the first pipe (13) extending downwards to the lev el lv a smaller distance from the bottom of the tank (19), whereas the second pipe ( 14) extends downwards to the level lv essentially at the bottom of the tank ( 19). and the two pipes ( 1 3a 14a) being open at their bottom portions so that the medium can get up into the same A central pressure sensor (33) is connected to the gasmedium main conduit (6) at a portion of the same between the first valve means (4) and the distribution valve means (7 8) connected in parallel, which pressure sensor accordinglv can sense the piessure in the two pipe parts (13a. 14a), The pressure sensor (33) is connected with a measuπng unit (30). which in its turn is connected with a computer (35). which on basis of the pressure, measured by the measuring unit, the volume of the tank (19) and the specific weight of the tank media calculates the volume of the two tankmedia. |
This invention relates to a method and apparatus for measuring the volume of a medium in a tank.
In certain cases it is very desirable and important to be able to determine the volume of a medium in a tank in a simple way and rather the change of volume This can for instance be the case if the tank contains a liquid, which is harmful to the environment, and it is necessary to discover a leakage quickly In this connection the volume/change of volume is determined by measuπng the pressure of the tank (M WC)
Furthermore, it is desirable to be able to determine the volume of a non-desirable liquid-phase in a tank containing petrol for instance This, non-desirable liquid could for instance be condensed water, which lays down on the bottom of tank, since water is heavier than petrol
This invention intends to provide a new and effective way lor measuring the volume of a medium/media in a tank, the result of the measuπng becoming more reliable than with known technique This has been made possible by the fact that the method comprises the steps mentioned in the main claim
A preferred embodiment of the apparatus according to the invention shall be described more closely below with reference to the accompanying drawing
The apparatus comprises a gas tube 1, which contains for instance nitrogen with a pressure of 100 bar This gas tube is connected with a volume stream regulator 2 via a first conduit 3 in the form of a pipe and this volume stream regulator is connected with a first valve means 4 via a second conduit 5 From the first valve means 4 goes out a third conduit 6 leading to six distribution valve means 7-12. connected in parallel, each of which in their turn via a conduit 13-18 is connected with a tank 19-23 In this connection the two first tank conduits 13, 14 are connected with one and the same tank 19 According to this embodiment all five tanks 19-23 are mutually different regarding the size
The conduits 14-18 in the form of pipes extend through respective tank 19-23 to the bottom of the same, that part of the conduit extending through the tank being denoted 14a- 18a.
The conduit 13, the part of which through the tank 19 being denoted with 13a, stops at a level above the level for the conduit 14.
Each of the six valve means 7-12, connected in parallel, is via a cable 24-29 connected with a measuring unit 30 This measuπng unit is via a further cable 31 also connected with the first valve means 4 and via a further cable 32 connected with a central
pressure sensor 33. which via a further conduit 34 is connected with that conduit 6 going from the first valve means 4 to the six distribution valve means 7-12. connected in parallel.
In order to store and register all data generated by the measuπng unit 30 there is a computer 35. which is connected to a printer 36. w hereby desirable data can be ted out I mm the computer.
Due to the shown and mentioned arrangement with a central pressure sensor, it is sufficient with one single pressure sensor. This fact means several advantages:
Firstly, the arrangement becomes considerably cheaper than having a pressure sensor at each tank. Secondly, it is possible to simply control the function ability of the pressure sensor via the measuring unit and the computer.
The invention functions in the following way . and it is presumed that a pressure reduction valve 37 in co-operation with the volume stream regulatoi 2 adiusts that pressure that shall be valid, for instance 1 bar. which is sensed by the pressure sensor 33 and is measured by the measuring unit 30. It is also presumed that when measuπng the volume ot the medium of the tank 19 that the level hi relates to the liquid level in the tank, that hi relates to the level for the lower end of the conduit part 13a. and that Iv, relates to the el for the lower end of the conduit part 14a. During the adjustment of the working pressure the distribution valves 7-12 are kept closed, whereas the valve means 4 is kept open
The first valve means 4 remains standing in open position, whereafter the first e means 7 is opened, which has the consequence that nitrogen of a pressure of 1 bar streams into the vertical conduit pipe 13a of the tank 19 so that the pipe 13a is emptied of its tank medium contents. This moment takes up to 3 seconds, so that it is made sure that the conduit pipe of the tank is completely emtied of the tank medium. After this moment the valve means 4 is closed, whereby the pressure sensor 33 senses the pressure of the tank 19 at the end of the conduit part 13a. which pressure stand in proportion to the liquid level hi in the tank 1 and gives an impulse to the measuπng unit 30. the measuring value of which is registered in the computer 35. This computer thereafter calculates the volume of the medium in the tank 19 between the levels hi and h? on the basis of the mentioned pressure, tank diameter and the specific weight of the tank medium, the result of the calculation appearing on the computer display and can be received as a print out from the printer 36
Thereafter the pressure in the conduit 14a is determined, the distribution valve 7 being closed and the distribution valve 8 is opened. In the computer the information about the volume between the levels h 2 and lv, is programmed. This volume \ alue corresponds lo a certain pressure for intended liquid medium (for instance petrol) in the conduit part 14a.
which pressure is sensed by the pressure sensor 33. Thus, if the measured pressure in the conduit part 14a should be greater than the predetermined pressure, this means that a liquid medium (condensation water) with a greater specific weight than petrol is positioned in the lower part of the tank. The size of the value of the difference between the measured pressure and the predetermined pressure indicates the volume size of the non-desirable liquid phase, i.e. the volume of the condensation water.
The shown arrangement in the tank 19 with two conduit pipes 13. 14. which end up at different levels makes accordingly possible to get valuable information about the size of the non-desirable liquid volume. If it is thereafter desirable to determine the medium volume in the second 20. third
21. fourth 22 and the fifth tank 23. respectively, the procedure will be the same as pre\ lously after that respective distribution value has been closed to the tank, already \ olume - calculated.
It should be pointed out that, when using closed tanks as is the case here, the value of the pressure sensor must be compensated with the difference between the pressure inside the tank and the atmospheric pressure, which difference can be either positive or negative depending upon the fact if overpressure or underpressure prevails in the tank abov e the liquid level of the same.
The invention is of course not limited to the shown and mentioned embodiment but can be modified within the scope ofthe following claims.
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