JP2842960B2 - Liquid volume measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level measuring device for a liquid tank of a space station, a general spacecraft, or the like.

[0002]

2. Description of the Related Art FIG. 3 shows two typical examples of conventional measurement of the amount of liquid in a liquid tank.

A first example is a level meter 02 for detecting a liquid level.
Is provided in the tank 01, thereby measuring the level of the liquid surface 03 formed in the tank 01. In this case, if the liquid level is settled horizontally, a predetermined measurement can be performed. However, in a tank of an oscillator (a ship or the like) or a tank of a space device, the liquid level 03 is not horizontal as shown in FIG. Measurement errors were sometimes large.

[0004] A second example is a discharge pipe 04 and a pump 0.
The flow rate integrating method using the flow meter 06 in the liquid supply line consisting of No. 5 was used. In this case, the flow meter 0
6, the integrated outflow amount = Σ (flow rate × time) was obtained, and this was subtracted from the initial liquid amount in the tank to obtain the remaining amount. It should be noted that the flow meter 06 can be replaced with an integrating flow meter.

[0005]

In the conventional liquid level measurement, when a level meter is used, there is a problem that a measurement error becomes large in a system in which the liquid level is not settled horizontally.

In the case of the flow rate integration method, the following measurement error occurs. In this case, the error of the liquid in the tank is expressed by the following equation. Error E = P (n-1) Here, P indicates an error of the flowmeter, and n indicates a ratio of initial tank liquid amount / residual amount.

For example, the error of the flow meter is 0.01 (1%)
When the remaining amount becomes 1/5 of the initial liquid amount, E = 0.01 × (5-1) = 0.04, and the remaining amount becomes 1 /
When it reaches 10, E = 0.01 × (10-1) =
0.09. That is, there is a problem that the error of the flow meter is integrated and the measurement error increases as the remaining amount decreases.

[0008] The present invention is to solve the above problems.

[0009]

According to the present invention, there is provided a liquid amount measuring device provided with a volume changer and a pressure detector provided on a top of a cylindrical liquid tank, and provided on a side wall of the liquid tank. A nozzle that is connected in the tangential direction of the liquid tank and injects the circulating liquid from inside the liquid tank into the tank, and a hydrophobic portion provided on the inner wall of the liquid tank around the measuring instrument. .

[0010]

In the above, when measuring the amount of liquid in the liquid tank, the circulating liquid from the tank is jetted into the tank by a nozzle to generate a circulation of the liquid in the tank.

In the swirling flow, the liquid does not reach the measuring device because the periphery of the measuring device on the top inner wall of the liquid tank is formed of a hydrophobic portion. Therefore, a lumped gas portion is formed around the measuring instrument in the liquid tank, and the measuring instrument can be used.

When the volume changer of the measuring device is operated in the above state, the pressure of the gas in the liquid tank is slightly changed. This pressure change is detected by the pressure detector, and the amount of the liquid in the liquid tank is changed. It is obtained by a gas volume method using a relational expression of gas volume / volume change / pressure change / initial pressure.

As described above, it is possible to use a measuring instrument having a volume changer and a pressure detector, and to measure the remaining amount of the liquid in the liquid tank by using the gas volume method. Can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS. This embodiment shown in FIGS. 1A and 1B includes a measuring instrument 10 provided on an opening 10 a provided at the center top of the tank 1, and an inner wall of the tank 1 surrounding the measuring instrument 10. A guard plate 12 made of an adhered hydrophobic material, a pump 5 provided on a discharge pipe 4 connected to the bottom of the tank 1, and a return pipe 11 provided as a branch pipe having a valve 14 on the discharge side of the pump 5. And a nozzle 13 connected to the end of the return pipe 11 and provided on the upper side wall of the tank 1 and connected in a tangential direction to the side wall. The measuring instrument 10 has a housing as shown in FIG. 20, a speaker 21 as a volume changer, and a microphone 22 as a pressure detector.

In the above description, when measuring the amount of liquid in the tank 1, the valve 14 is opened, and the reflux liquid is introduced into the tank 1 from the nozzle 13 as shown in FIG. The liquid flows in the tangential direction, and both the liquid and the gas form a swirling flow in the tank 1 as a whole. Therefore, due to the difference in mass in the centrifugal force field, the liquid is deflected outward and the gas is deflected inward, and is separated into a gas part 8 and a liquid part 9 as shown in FIG. At this time, since the guard plate 12 is hydrophobic, liquid does not adhere thereto, and a gas-liquid boundary is formed on the outer edge of the guard plate 12. Therefore, the liquid does not reach the measuring instrument 10 inside the guard plate 12. Therefore, it is possible to use a speaker and a microphone for gas, and this measurement is established.

The measurement of the amount of liquid in the tank 1 in the present embodiment utilizes the gas volume method, and the procedure will be described below. That is, first, the speaker 21 which is a volume changer is operated to minutely change the volume of the gas in the tank 1. Then, since the pressure slightly changes due to the nature of the gas, the pressure is measured by the microphone 22 as a pressure detector, and the values of both are entered into a relational expression of volume / volume change / pressure change / initial pressure of gas. , The gas volume is subtracted from the tank volume to determine the remaining liquid.

As the volume changer, there are a piston type and a bellows type in addition to the speaker, but the speaker type is the simplest device. However, the loudspeaker system does not operate when the loudspeaker is immersed in a liquid, and an error occurs even if the gas is divided into two or more lump.

Therefore, it has been considered that application is difficult when the speaker is likely to be immersed in the liquid in a tank of a ship, an airplane, a spacecraft, or the like described above. However, as shown in FIG. 1A, the gas is unified (not two or more), so that a speaker system can be adopted.

Although the guard plate 12 is used in this embodiment, the inner wall of the tank may be coated directly with a hydrophobic material instead. Instead of using the pump 5 of the discharge pipe 4, a small pump may be provided separately and an independent return pipe system may be provided.

As described above, since the speaker and the microphone can be used and the remaining amount of the liquid in the tank is measured by using the gas volume method, the measurement accuracy can be improved and the measurement cost can be reduced.

[0021]

According to the flow rate measuring device of the present invention, the nozzle generates a swirling flow of the liquid in the liquid tank, and the swirling flow and the hydrophobic portion around the measuring device form one lump around the measuring device. Enabled the formation of a gas part, the volume changer of the measuring instrument slightly changed the gas pressure, and the pressure detector detected it,
By determining the amount of liquid in the liquid tank using the gas volume method, it is possible to improve measurement accuracy and reduce measurement cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, wherein (a) is a side view and (b) is a plan view.

FIG. 2 is a detailed explanatory diagram of a measuring device according to the one embodiment.

FIG. 3 is an explanatory diagram of a conventional measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 5 Pump 10 Measuring instrument 11 Return pipe 12 Guard plate 13 Nozzle

Continuation of the front page (72) Inventor Makoto Fujiwara 2-1-1, Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-3-92725 (JP, A) JP-A-55 -119015 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 17/00 G01F 22/02

Claims (1)

(57) [Claims] 1. A measuring instrument provided at the top of a cylindrical liquid tank and having a volume changer and a pressure detector, and is provided on a side wall of the liquid tank and connected in a tangential direction of the side wall to reflux from inside the liquid tank. Nozzle that injects liquid into the tank,
And a hydrophobic part provided on an inner wall of the liquid tank around the measuring instrument.