JPS6110725A - Apparatus for detecting remaining amount of liquid - Google Patents

Abstract

PURPOSE:To make it possible to detect the remaining amount of liquid even if the remaining amount of the liquid becomes less, by providing a sub-tank in the liquid feeding path of a tank, coupling a piston in said sub-tank, and detecting the moving position of the piston. CONSTITUTION:A liquid, which is filled in a tank 1, is pushed by a compressing gas, which is compressed from a gas storing device 3 through an inlet pipe, and sent out of gas feeding pipes 7a and 7b through a mesh screen. A cylinder shaped sub-tank 20 is provided between the gas feeding pipes 7a and 7b. In this sub-tank 20, a piston, whose front and back surfaces are linked through the mesh screen, is coupled. The moving position of the piston is detected by a position detector. The remaining amount of the liquid in the tank 1 is detected based on the detected signal.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is particularly applicable to the use of liquids stored in tanks, such as propellants for attitude control of space equipment, into pressurized gas under zero gravity conditions such as outer space. The present invention relates to a device for detecting the remaining amount of liquid in a device that extrudes and delivers the liquid.

[Prior art]

In a zero-gravity environment such as outer space, the storage location of liquid stored in a tank is not determined, so an appropriate collection device is required to continuously send out the liquid. For example, AIAA Paper A73-1
The principle is explained in No. 208. In addition, the liquid remaining amount detection means is, for example, MES8ER8OHMITT-B6LK.
OW-BLOHM (prepared by: MBB
5pace Division, Departme
nt RX 26 +Qttobrunn, ])e
6th + 1976). Is the following an example of a concrete implementation of these conventional technologies? This will be explained using FIG.

In the figure, 1 is a spherical tank, 2 is a feed pipe for feeding the pressurized gas such as helium or nitrogen gas into this tank, and this feed pipe is connected to a gas accumulator 3 for the pressurized gas. be done. 5
1 is a liquid collection cell built into the tank 1, which is made up of a plurality of hollow semicircular arc-shaped cell members 6ft joined together to form a liquid shape as a whole. This is a liquid delivery pipe connected to the seven cells 5 and drawn out of the tank 1. Further, the cell member 6 is provided with a large number of transparent windows 8 on its inner and outer sides, and these transparent windows and a mesh screen 9 are used as a barrier. mesh screen 9
The size of these pores or meshes is determined by the surface tension of the target liquid. The size is such that it can be retained and close the pores.

In the above configuration, the liquid filled in the initial tank 1 is pushed by the pressurized gas sent from the gas accumulator 3 through the feed pipe 2, passes through the mesh screen 9, and is sent out from the delivery pipe 7. be done. With this delivery, the gas phase area in the tank 1 becomes larger and the cell 5 is exposed to this gas phase area, but the mesh screen 9 retains the liquid filling the cell 5 in its pores. Since a gas-liquid interface is formed due to surface tension, communication between the exposed portion and the gas phase region is interrupted. Therefore, Se/11
The cell 5 continues to collect and deliver only liquid from the liquid phase region while blocking the inflow of pressurized gas, and continues to form the gas-liquid interface while replenishing the liquid inside the cell 5. When the tank 1 becomes almost empty in this way, it becomes impossible to replenish the liquid into the cell 5, and as a result, the gas-liquid interface tends to break, so the pressurized gas breaks through the interface and flows into the cell 5. Then, the liquid inside this cell is pushed out.

On the other hand, 10 is a liquid remaining amount detection means, 11 and 12 are respectively attached to the tank 1, and are a pressure sensor and a temperature sensor for detecting the pressure and temperature of the pressurized gas, and 13 is a computing unit. The calculator 13 receives the pressure and temperature signals sp and i3t detected by these sensors 11 and 12, and calculates the volume of the gas based on the gas state equation.
Compare this with the initial volume and calculate the increased volume, that is, the displaced volume of liquid, to find out the remaining amount? The calculation is performed, and the result is sent as a remaining amount signal S to the control unit of the space equipment. Based on the signal S, this control section predicts the life of the attitude control device, etc.

〔problem〕

However, in such conventional remaining amount detection means, the detection accuracy decreases particularly in the final stage when the remaining amount of liquid becomes small. Therefore, even though it is necessary to improve the accuracy of life prediction etc. in this terminal stage, there is a problem that this cannot be achieved.

One reason for this is that as the excluded volume increases, the rate of change in pressure with respect to that increment decreases, resulting in a decrease in the resolution of the pressure sensor.The second reason is that the detected value of the temperature sensor is affected by the environmental temperature. Due to this influence, the larger the excluded volume, the more the calculation result will be affected. For example, the error introduced will also become larger.

[H subject of invention]

In view of the above problems, an object of the present invention is to accurately detect the remaining amount of liquid, especially when the remaining amount of liquid becomes small.

〔composition〕

In order to solve the above problems, the remaining amount detection means of the present invention includes a cylinder-shaped sub-tank interposed in the liquid delivery path of the tank, and a mesh screen or mesh screen installed in the sub-tank. A piston is fitted with the front and back connected through a piston, and a position detector is attached to detect the movement position of this screw.The position signal of this detector is used to detect the remaining amount of liquid. It is something.

[Embodiment 1] FIGS. 2 and 3 show an example in which the present invention is applied to a gas pressurized liquid delivery device having the same configuration as that in FIG. A quantity detection means 10 is also provided in the same manner.

Is 20 the aforementioned delivery pipe? (7a, 7b), and its capacity is smaller than that of the tank 1 (hereinafter referred to as main tank 1).

Mainly used in Fig. 3, there is a tank main body formed in the shape of a cylinder with a bottom, 22 is a lid attached to this main body by tightening (Z3), and 24 and δ are connected to the delivery pipes 7a and 7b, respectively. This is a connector attached to the lid η and the bottom plate of the main body 21 for joining.

A piston 26 is slidably fitted into the main body 21, and consists of an annular member I, a mesh screen N attached to the bore of this member so as to oppose each other, and an O-ring 4 fitted into the annular member 27. , mesh screen n is similar to mesh screen 9 of the cell. and piston 26
is positioned relatively above the main body 21 by utilizing the strength of the O-ring 4. In this specification, the terms "upper" and "lower" refer to the drawings. (030 indicates an annular magnet fixed to the upper surface of the piston 26)
, 3H2 is a piston position detector attached to the side surface of the main body 21, and is equipped with a plurality of reed switches 32a, 32b, . . . 32n that are activated when facing the magnetic recess. Then, when the magnet 30 faces the highest reed switch 32a and the lowest reed switch 32n, each reed switch is arranged so that the volume below the piston becomes a predetermined value and approximately zero. Allocate the position of.

Effect? explain. Initially, the liquid is filled in both the main tank 1 and the sub-tank, and in this case, no surface tension acts on the pores of the mesh screen 28, so the front and rear surfaces of the piston 9 are filled with fluid. will be contacted.

Therefore, when pressurized gas is introduced into the main tank 1 to push out liquid as described above, the liquid passes through the sub-tank from the delivery pipe 7a and is delivered via the delivery pipe 7b. When the main tank 1 becomes empty, the pressurized gas flows into the cell 5 and pushes out the liquid in the cell as described above, and finally flows into the sub tank 20, which then fills the space above the piston 9.

Here, the front (upper part) of the mesh screen is in contact with the gas phase region while the back thereof is held by the liquid L', so that the gas-liquid interface is formed in the pores of the mesh screen and prevents the pressurized gas from permeating therethrough. Therefore, the piston 26 is pushed down by this pressurized gas and moves inside the main body 21, and finally moves into the reed switch 32a.

32b...32n and operate them sequentially.

Since these reed switches are distributed as described above, the position of the piston is detected each time they are activated, and thereby the volume below the piston, and therefore the remaining amount of liquid, can be accurately detected. This detection result, that is, the position signal Sr of the piston 26, is sent to the control section of the space equipment, and this control section performs life prediction etc. based on the new signal Sr.

[Embodiment 2] The embodiment shown in FIG. 4 is an example in which a sub-tank and a main tank 1 are internally equipped.

In the drawing, 7 is the delivery pipe, which is attached to the main tank 1 in this case. 41 is a sub-tank in the form of a covered cylinder welded to the main tank 1, the lower part of which communicates with the delivery pipe 7, and the upper part of which has a through hole 42? Prepare. A piston 43 is fitted into the sub-tank 41 and is provided with an annular member 44 with an 01J ring and a mesh screen 45, similar to the piston shown in FIG.

46 is a rod suspended from this mesh screen to the inside of the delivery pipe T, 47 is a magnet fixed to the lower end of this rod, and the north part is a piston position detector attached to the delivery pipe 7, as shown in Fig. 3 (31) Similarly, it is equipped with a reed switch that can be faced sequentially with the magnet 47.5
0 is a covered housing 71, which is concentric with the sub-tank 41 and welded to the main tank 1, and is connected to the lower end of the cell opening 6 of the cell 5 and this housing 50 to communicate with each other. The other configurations are the same as those of the prior art.

In this embodiment, when pressurized gas flows into the cell 5 and reaches the housing 50, the gas fills above the piston 43 through the through hole 42 while pushing out the liquid in the housing. Hee here.

The magnet 47 is pressed down and the rod 46 is the same as in the first embodiment. While moving simultaneously with this piston, the IJ-doswitches of the position detector 48 are sequentially activated to transmit the position signal Sr.

In this embodiment, the sub-tank 41 is housed inside the main tank 1, which facilitates the layout of space equipment and the like.

[Embodiment 3] In FIG. 5, 60 is the primary sub-tank and the delivery pipe 7
(7C, 7d), 61 is a cylinder-shaped main body, 62 is a lid, and 0 is a piston fitted in main body 61. This piston 63 generally consists of a bore of an annular member 64 with an O-ring made of a magnet and a mesh screen 65 similar to the above. Reference numeral 66 denotes a position detector for the piston field, and a lower reed switch opening is installed so as to face an annular member 64 made of a magnet when the piston 63 is at the lowest position, and a lower reed switch opening is installed at a predetermined distance from this reed switch. An upper reed switch 68 is provided.

70 is a branch W7e of the delivery pipe 7C and a branch pipe 1f of the same 7d.
A piston 76 consisting of a bottomed cylinder-shaped main body 71, a lid body 72, an annular member 77 with an 01,1 ring 79, and a mesh screen T8 is interposed between the third sub-tank and the third sub-tank. It is equipped in the same manner as the sub-tank shown in the figure. However, 30 magnets in the figure have been removed.

■, is a normally open pneumatic valve installed in the delivery pipe 7d on the upstream side of the branch pipe 7f, and ■2 and V are the branch pipe 7, respectively.
Normally closed pneumatic valves 80 and 7f are interposed, and 80 is an operation controller that controls switching of these valves.

Explain the action.

Initially, the primary and secondary sub-tanks 60 and 70 are filled with liquid. When the main tank is emptied and pressurized gas flows into the primary sub-tank 60 from the delivery pipe IC and fills above the piston 63, this piston is pushed down by the aforementioned action of the mesh screen 65. , the annular member 64 faces the upper reed switch 68.

The switch is now actuated to generate the first position signal Sr.

I will send this message. The total remaining amount at this time corresponds to the sum of the remaining amount of the primary sub-tank and the volume of the secondary sub-tank, so it is a known value. Then, when the piston B reaches the lowest position, the lower reed switch nail is activated and sends out the second position signal Sr, whereby it is detected that there is a remaining amount corresponding to the volume of the secondary sub-tank 70. . At the same time, the actuation controller receives the signal Sr and operates the pneumatic valves N71 + Vt and V
.

? Switch at the same time. Therefore, the pressurized gas flows into the secondary sub-tank 70 via the branch pipe 78, and liquid is pushed out and delivered from the sub-tank 70 in the same manner as described with reference to FIG.

In this embodiment, in addition to using the signals Sr and Sr2 for direct control, these signals are sent to the conventional calculation M13 to be corrected with the calculation results up to that point. Remaining amount detection accuracy using means 10?
can be improved.

〔effect〕

As explained above, according to the present invention, the remaining amount of liquid stored under zero gravity can be detected without fail until the end, so the control life of space equipment, etc. can be reduced, especially at the end of the period when the remaining amount is low. This is what makes predictions accurate.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a liquid delivery device equipped with a conventional residual amount detection means, FIG. 2 is an overall view of a liquid delivery device embodying the present invention, and FIG. 3 is a cross-sectional view of a main part of FIG. 2. , FIG. 4 is a sectional view of the main part showing another embodiment, and FIG. 5 is still another embodiment? FIG. DESCRIPTION OF SYMBOLS 1... Tank 3... Pressurized gas accumulator 5... Cell for collecting liquid 7... Liquid delivery pipe 10... Conventional remaining amount detection means Addition, 41... Sub-tank 60... Primary sub-tank 70-...
Secondary tank redundancy, 43, 63, 76... Piston 28, 45, 65, 78... Mesh screen 31, 48, 66... Piston position detector S
r, Sr, + Sr, ++・Position signal patent applicant Nissan Motor Co., Ltd. Figure 7 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a device that pushes out liquid stored in a tank using pressurized gas, a cylindrical sub-tank is interposed in the liquid delivery path of the tank, and this sub-tank includes a piston whose front and back surfaces are connected through a mesh screen. A liquid remaining amount detection device that is fitted with a piston, is attached with a position detector that detects the moving position of this piston, and detects the remaining amount of liquid based on the position signal of this detector.