JPH04102600A - Liquid transferring device - Google Patents

Abstract

PURPOSE:To greatly reduce troublesomeness in maintenance and supervising by providing an overflow pipe with its opening provided to a specified height of the liquid level, in a pressure-regulating tank, and by providing a drain pipe which guides the liquid overflowing the overflow pipe to a receiving tank. CONSTITUTION:With a vacuum pump 10 started with a three-way valve 11 driven and a pressure-regulating tank 4 communicated with the vacuum pump 10, liquid 2 in a liquid storage tank 1 is sucked up at a fixed flow rate through a suction pipe 6, and is stored in the pressure-regulating tank 4. The liquid sucked up to the pressure- regulating tank 4 and stored therein flows over the upper edge of an overflow pipe 7 and runs down the inside of a drain pipe 8 and is delivered toward a receiving tank 3. The delivery is made in natural running-down by head pressure corresponding to the difference H4+H3 between the upper edge of the overflow pipe 7 provided in the pressure-regulating tank 4 and the level of the liquid in the receiving tank 3. The height (h) to the level of the liquid in the liquid storage tank 1 is detected with a transmitter-equipped liquid level measuring instrument 13. When the level of the liquid comes near to the lower end of the suction pipe 6, the three-way valve 11 is communicated with the atmosphere side by operation of an adjuster 14, and thereby the inside of the pressure-regulating tank 4 is released from depressurized state and transfer of the liquid is stopped.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a liquid transfer device, and in particular, it is capable of transferring a liquid at a constant flow rate, and a flow rate measuring device is provided in the wetted part. ,
No need for moving equipment such as pumps or flow control valves.
The present invention relates to a liquid transfer device that has a simple device configuration and is extremely easy to maintain and manage.

(Prior Art) Many waste liquids discharged from chemical factories and nuclear power-related facilities are highly toxic and corrosive, and when processing them, it is necessary to be careful in handling the transfer. In particular, it is necessary to reduce radiation exposure as much as possible with respect to radioactive liquid waste discharged from nuclear-related facilities, and waste liquid treatment equipment is installed in a controlled area separated from general work areas.
In addition, they are often installed in locations where it is difficult to easily carry out maintenance and management work.

Such waste liquid treatment equipment requires a transfer device that transfers the liquid at a constant flow rate in order to maintain the stability of treatment operations. It is constructed by disposing movable devices such as a flow rate measuring device, a pump, and a flow rate regulating valve within a piping system that circulates liquid.

(Problem to be solved by the invention) However, in conventional transfer devices, movable equipment such as pumps and flow control valves come into direct contact with highly corrosive and toxic liquids, resulting in corrosion damage to movable parts and performance deterioration. However, it is necessary to periodically stop the device for maintenance inspection and parts replacement, which has the disadvantage that maintenance work requires a great deal of effort and time.

In particular, in transfer equipment that handles radioactive waste liquid, the radiation exposure of workers increases and the risk of direct contact with the waste liquid is high.
Some kind of countermeasure was desired.

The present invention has been made to solve the above-mentioned problems, and it is possible to simplify the configuration of the device without using equipment with moving parts in wetted parts, and to significantly reduce maintenance work. Another object of the present invention is to provide a liquid transfer device capable of transferring liquid at a constant flow rate.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a liquid transfer device for transferring liquid stored in a liquid storage tank to a receiving tank, in which a pressure regulating tank is disposed at a higher location than the liquid storage tank and the receiving tank, Equipped with a pressure reducing device that adjusts the internal pressure of this pressure regulating tank to a predetermined value, and connecting the upper end of a suction pipe that sucks up the liquid in the liquid storage tank by reducing the pressure in the pressure regulating tank to the bottom of the pressure regulating tank, The present invention is characterized in that an overflow pipe having an opening at a predetermined liquid level height in the pressure regulating tank is provided, and a discharge pipe is provided for guiding the liquid overflowing from the overflow pipe to the receiving tank.

(Function) In the liquid transfer device having the above configuration, the pressure inside the pressure adjustment tank is reduced by the pressure reducing device and adjusted to a predetermined pressure value, so that the liquid stored in the liquid storage tank passes through the suction pipe and the pressure is adjusted. It is sucked up into the tank. Of the liquid sucked up, the liquid above the opening of the overflow pipe overflows from the overflow pipe at a constant flow rate and is transferred to the receiving tank by gravity due to the head difference between the pressure adjustment tank and the receiving tank. Ru.

As described above, according to the liquid transfer device according to the present invention, the pressure in the pressure adjustment tank can be adjusted without installing movable devices such as a flow rate measurement device, a pump, or a flow rate control valve in the liquid contact portion of the liquid transfer path. The liquid can be transferred at a constant flow rate. In addition, because there are no movable devices in the wetted parts, there is no damage or deterioration of moving parts like in conventional equipment, and maintenance and inspection of the equipment is easy, allowing continuous operation of the equipment over long periods of time. can do.

Particularly in equipment that handles radioactive liquids, the radiation exposure of maintenance workers can be significantly reduced as maintenance and inspection time is shortened.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of a liquid transfer device according to the present invention.

That is, the liquid transfer device according to this embodiment is a liquid transfer device that transfers liquid 2 stored in a liquid storage tank 1 to a receiving tank 3, in which a pressure regulating tank 4 is arranged at a higher location than the liquid storage tank and the receiving tank 3, and A pressure reducing device 5 is installed to adjust the internal pressure P1 of the pressure regulating tank 4 to a predetermined value. An overflow pipe 7 is connected to the bottom of the pressure regulating tank 4 and has an opening at a predetermined liquid level height in the pressure regulating tank 4, and a discharge pipe 8 is provided to guide the liquid 2 overflowing from the overflow pipe 7 to the receiving tank 3. Arranged and configured.

Further, the pressure reducing device 5 is interposed in the pressure reducing pipe 9 and a vacuum pump 10 that exhausts the gas phase part in the pressure regulating tank 4 via the pressure reducing pipe 9, and is installed in the pressure reducing pipe 9 to close the flow path of the gas in the pressure regulating tank 4. or
The three-way valve 11 that switches to the atmosphere side or the vacuum pump 10 side and the differential pressure between the pressure adjustment tank 4 and the liquid storage tank 1 (P 2
A differential pressure transmitter 12 that detects P + ), a liquid level gauge 13 with a transmitter that detects the liquid level in the liquid storage tank 1, and a liquid level detection signal from the liquid level gauge 13 with a transmitter and a differential pressure transmitter. 12, and a regulator 14 which outputs a drive signal to drive the three-way valve 11 in order to control the pressure P1 in the pressure regulating tank 4 to a predetermined value.

Further, the lower end of the discharge pipe 8 connecting the pressure regulating tank 4 and the receiving tank 3 is immersed in a pit-shaped recess 15 formed at the bottom of the receiving tank 3. Even when almost all of the liquid in the receiving tank 3 is discharged, a sufficient amount of liquid remains in the recess 15 to fill the discharge pipe 8.

Further, since the inner diameter of the discharge pipe 8 is set to be larger than that of the suction pipe 6, even if deposits or the like adhere to the inside of the discharge pipe 8, there is little possibility that the flow rate of the flowing liquid will change.

The inner surface of the suction pipe 6 is lined with a material such as SUS, which has excellent corrosion resistance and wear resistance, to prevent the inner surface from becoming rough due to corrosion, etc., and to prevent fluctuations in the flow path cross-sectional area and flow coefficient. good.

Furthermore, when the pressure inside the pressure adjustment tank 4 is reduced by the vacuum pump 10,
In order to prevent liquid from flowing back through the discharge pipe 8 from the receiving tank 3 side to the pressure adjustment tank 4 side, the height of the discharge pipe 8 (H3 + H
4) is set larger than the lift height H in the suction pipe 6.

When transferring the liquid 2 in the liquid storage tank 1 to the receiving tank 3, first a step of sucking up the liquid 2 into the pressure adjustment tank 4 is performed.

That is, when the vacuum pump 10 is started with the three-way valve 11 being driven to communicate the pressure adjustment tank 4 with the vacuum pump 10, as the pressure inside the pressure adjustment tank 4 is reduced, the liquid flows through the suction pipe 6 and into the liquid storage tank 1. The liquid 2 inside is sucked up at a constant flow rate and stored in the pressure regulating tank 4. At this time, the liquid in the discharge pipe 8 is also sucked back to the pressure regulating tank 4 side, but since the height of the discharge pipe 8 (H3 + H4) is greater than the lift height H1 of the suction pipe 6, the pressure is increased from the receiving tank 3 side. The liquid does not continuously flow back to the adjustment tank 4 side, and is balanced when a liquid head pressure corresponding to the degree of pressure reduction in the pressure adjustment tank 4 is generated. Further, since the liquid stored in the recess 15 of the receiving tank 3 sufficiently fills the discharge pipe 8, there is no fear that the water seal in the discharge pipe 8 will break.

That is, when the pressure inside the pressure adjustment tank 4 is reduced to Pi,
Although the liquid rises in the discharge pipe 8 until a wave crest corresponding to the pressure P1 is generated, air does not enter the discharge pipe 8 and the depressurization operation becomes impossible.

The liquid sucked up and stored in the pressure regulating tank 4 overflows at a constant flow rate from the upper edge of the overflow pipe 7, passes through the discharge pipe 8, and is discharged in the direction of the receiving tank 3. This discharge is carried out in the pressure adjustment tank 4.
This is done by gravity due to the head pressure (liquid head pressure) corresponding to the difference (H4+H3) between the upper edge of the overflow pipe 7 provided inside and the liquid level height in the receiving tank 3 (H4+H3).

The liquid level height h in the liquid storage tank 1- is detected by the liquid level gauge 13 with a transmitter, and when the liquid level h falls to near the lower end of the suction pipe 6, the three-way valve 11 is opened to the atmosphere by the regulator 14. The pressure regulating tank 4 is rotated so as to be in communication with the side, the reduced pressure state in the pressure regulating tank 4 is released, and the transfer of the liquid 2 is stopped.

Here, the liquid 2 is passed from the liquid storage tank 1 through the suction pipe 6 to the pressure adjustment tank 4 without causing the water seal in the discharge pipe 8 to break.
In order to siphon the water into the tank, it is necessary to set the pressure P in the pressure adjustment tank 4 within the range of equation (1) below.

P2-pH2>P, >P3-pH3...(]
) Here, P2 is the pressure acting on the liquid level of the liquid storage tank 1, and P3
is the pressure acting on the liquid level in the receiver tank 3, ρ is the specific gravity of the liquid, H2 is the height from the bottom of the liquid level storage tank 1 to the upper edge of the overflow pipe 7, H3 is the height from the liquid level in the receiver tank 3 to the pressure adjustment tank 4 This is the height to the bottom of the

In addition, in a state where the pressure in the pressure adjustment tank 4 is maintained at Pl, the flow rate q of the liquid 2 sucked up per unit time by the suction pipe 6 is expressed by the following formula (2) % formula % Here, is the suction pipe 6 is the overall flow rate coefficient, a is the liquid passage cross-sectional area of the suction pipe 6, g is the mold plate acceleration, and h is the liquid depth in the liquid storage tank 1.

Therefore, as is clear from equation (2), (P2-P,)
By controlling -ρ(H2-h) to be constant, q becomes constant, and the liquid 2 can be transferred at a constant flow rate.

Here, the difference (P2 PI) between the pressure P2 in the liquid storage tank 1 and the pressure P in the pressure adjustment tank 4 is detected by the differential pressure transmitter 12, and the detection signal is input to the regulator 14.

On the other hand, the lift height from the liquid storage tank 1 to the pressure adjustment tank 4 (H2-h
) is detected by the level gauge 13 with a transmitter, and the detection signal is also input to the regulator 14.

The regulator 14 adjusts [(P2-p
)-ρ(H2-h)], outputs a control signal to rotate the three-way valve 11 so that this value becomes a predetermined value, and sets the pressure P1 in the pressure regulating tank 4 to a predetermined value. Set to .

In order to ensure free fall of the liquid 2 within the discharge pipe 8, the liquid passage cross-sectional area of the discharge pipe 8 is set within the range expressed by the following equation (3).

Here, 2 is the flow coefficient of the entire discharge pipe 8, and H4 is the height from the bottom of the pressure regulating tank 4 to the upper edge of the overflow pipe 7.

In addition, in equation (2), assuming that the liquid storage tank 1 is an air-open tank with a sufficiently large capacity compared to the suction amount and that there is no fluctuation in P2 and h, the liquid flow rate q in the pressure adjustment tank 4 is It is uniquely determined by the pressure P1 of .

As described above, according to the liquid transfer device according to this embodiment, by adjusting the pressure in the pressure adjustment tank 4, the liquid 2 can be transferred from the liquid storage tank 1 to the receiving tank 3 at a constant flow rate.

In particular, in the device of this embodiment, there is no need to provide movable equipment such as a flow rate measuring device, pump, or flow rate regulating valve in the wetted part.
The device configuration is extremely simplified and handling is easy. Therefore, there are almost no failures of the component equipment, and the operation and maintenance of the device is extremely easy, allowing continuous operation over a long period of time.

Next, another embodiment of the present invention will be described with reference to FIG. In addition to the configuration shown in FIG.
6 is disposed, and an ultrasonic liquid level gauge 17 for detecting an abnormal rise in the liquid level in the pressure regulating tank 4 is installed on the top of the pressure regulating tank 4.

The mounting height H3 of the liquid reservoir 16 is set so that the liquid does not rise even when the maximum pressure P that is considered to act on the liquid storage tank 1 acts on the liquid storage tank 1.
ff1l at a position higher than the height expressed by /ρ! provided.

According to this embodiment, even if the inside of the pressure adjustment tank 4 is excessively depressurized due to a malfunction or the like or excessive internal pressure is applied inside the liquid storage tank 1, the liquid rising through the depressurization pipe 9 is kept in the liquid reservoir 16. stored. Therefore, liquid is prevented from entering the three-way valve 11 and causing damage.

In addition, even if the pressure inside the pressure adjustment tank 4 is reduced, the liquid 2 may not be sucked up into the pressure adjustment tank 4, or conversely, the liquid level in the pressure adjustment tank 4 may rise abnormally and the liquid level may rise to a preset abnormal level ( Hab
), those abnormalities are detected by the ultrasonic liquid level gauge 17. The detection signal is sent to the regulator 14a,
The regulator deactivates the device. Therefore, damage to equipment due to abnormal rise or fall of the liquid level can be prevented.

〔Effect of the invention〕

As explained above, according to the liquid transfer device according to the present invention, the pressure in the pressure regulating tank can be adjusted without disposing movable equipment such as a flow meter, a pump, or a flow control valve in the liquid contact part of the liquid transfer path. Adjustment allows liquid to be transferred at a constant flow rate. Therefore, the movable parts are not damaged or deteriorated, maintenance and inspection of the device is easy, and the device can be operated continuously over a long period of time.

Particularly in equipment that handles radioactive liquids, the radiation exposure of maintenance workers can be significantly reduced as maintenance and inspection time is shortened.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a liquid transfer device according to the present invention, and FIG. 2 is a sectional view showing another embodiment of the present invention. 1...Liquid storage tank, 2...Liquid, 3...Receiving tank, 4...
... Pressure adjustment tank, 5 ... Pressure reduction device, 6 ... Suction pipe, 7 ... Overflow pipe, 8 ... Discharge pipe, 9 ... Pressure reduction piping, 10 ... Vacuum pump, 11... Three-way valve, 12...
・Differential pressure transmitter, 13...Liquid level gauge with transmitter, 14.14
a...Adjuster, 15...Recess, 16...Liquid reservoir,
17...Ultrasonic liquid level gauge.

Claims (1)

[Claims] In a liquid transfer device that transfers liquid stored in a liquid storage tank to a receiving tank, a pressure regulating tank is installed at a higher place than the liquid storage tank and the receiving tank, and a pressure reducing device is installed to adjust the internal pressure of this pressure regulating tank to a predetermined value. , an overflow pipe having an opening at a predetermined liquid level height in the pressure regulating tank, the upper end of which is connected to the bottom of the pressure regulating tank for sucking up the liquid in the liquid storage tank by reducing the pressure in the pressure regulating tank; 1. A liquid transfer device characterized in that a discharge pipe is provided for guiding the liquid overflowing from the overflow pipe to a receiving tank.