JPH07280618A - Liquid weighing apparatus and cleaning apparatus provided with the same - Google Patents

Abstract

PURPOSE:To provide a liquid weighing apparatus in which a liquid can be weighed without discharging the liquid. CONSTITUTION:The liquid weighing apparatus 10 comprises a weighing tank 12 comprising a cylindrical vertical vessel, a supply pipe 14 with an ON/OFF valve 22, an overflow pipe 16, a delivery pipe with an ON/OFF valve 18, a lower limit liquid level sensor 28, and a liquid level sensor 30. The apparatus 10 further comprises a receiving tank 40 disposed closely to the side wall of the weighing tank 12 on the outside thereof, and a pipe 44 with an ON/OFF valve 42 communicating the receiving tank 40 and the weighing tank 12. The receiving tank 40 is interposed between the upper end opening of the overflow pipe 16 and the bottom plate 50 of the weighing tank 12. The communication pipe 44 extends from the bottom plate 50 of the receiving tank 40 to be coupled with the side wall of the weighing tank 12 and the ON/OFF valve 42 disposed in the way of the communication pipe 44 is closed upon expiration of a timer 52. When the liquid is weighed, the liquid flowed over the overflow pipe 16 is temporarily received by the receiving tank 40 and a constant quantity of liquid is delivered from the weighing tank 12 before the received liquid is transferred to the weighing tank 12. This constitution eliminates useless discharge of liquid at the time of weighing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid weighing device having a positive displacement weighing tank equipped with an overflow pipe, and a cleaning device having a similar chemical liquid weighing device,
More specifically, the present invention relates to a liquid weighing device and a cleaning device that collects a liquid overflowing from a weighing tank via an overflow pipe and prevents the liquid from being wastefully discharged.

[0002]

2. Description of the Related Art There are various types of liquid weighing devices for weighing a liquid to a predetermined volume. Among them, a liquid weighing device using a positive displacement weighing tank equipped with an overflow pipe can easily and accurately quantify a liquid. It is used in various fields. For example, in a semiconductor device manufacturing process, various cleaning operations are performed on a wafer or an object to be cleaned such as a semiconductor device. In the process of cleaning wafers or semiconductor devices, various chemicals are mixed with water to prepare cleaning water according to the cleaning purpose, and an object to be cleaned, such as a wafer, is cleaned in a cleaning tank containing the cleaning water. Alternatively, the cleaning object is cleaned by spraying cleaning water onto the cleaning object. When preparing the wash water, strictly control the preparation of the wash water in order to prevent excess chemical components in the wash water from adversely affecting the object to be cleaned, that is, the amount of the chemical added. It is necessary to strictly manage

Therefore, in a cleaning device for a semiconductor device or the like, a chemical solution weighing device as shown in FIG. 2 is used to accurately quantify the chemical solution and then supply it to a mixing tank to prepare cleaning water. Figure 2
The chemical solution weighing device shown in is a facility attached to an automatic cleaning device used in a semiconductor device manufacturing process, and includes a weighing tank 12 and a supply pipe 14 for supplying a chemical solution to the weighing tank 12.
An overflow pipe 16 for overflowing an excessive amount of the chemical liquid from the weighing tank 12 to make the amount of the chemical liquid in the weighing tank 12 constant, and an on-off valve 18 for delivering the chemical liquid from the weighing tank 12 are provided with the weighing tank 12 And a delivery tube 20 connected to the bottom of the. The weighing tank 12 is
A liquid container of a cylindrical closed type or an upper open type, in which the liquid is supplied from the supply pipe 14 and overflowed from the upper end opening 24 of the overflow pipe 16 so that the liquid is quantitatively determined. is there.

The supply pipe 14 is provided with an opening / closing valve 22, and the other end (not shown) of the pipe is connected to a chemical liquid tank (not shown) for storing a cleaning chemical liquid. When is opened, the chemical solution is supplied from the chemical solution tank. Overflow pipe 16
Has an upper end opening 24 located at a predetermined level in the weighing tank 12, descends inside the weighing tank 12 and penetrates the bottom plate, and a lower end opening 26 is located at a predetermined place, for example, a chemical solution discharge groove (not shown). Is located in. When the chemical solution just overflows from the overflow pipe 16, the weighing tank 1
The position of the upper end opening 24 of the overflow pipe 16 is determined so that the amount of the chemical solution contained in 2 becomes a predetermined amount.
The delivery pipe 20 is connected to a cleaning water preparation tank (not shown) of the main body of the automatic cleaning device via the on-off valve 18.
When is opened, the drug solution quantified in the weighing tank 12 can be charged into the preparation tank.

The liquid weighing device further includes a lower limit liquid level sensor 2
8, a quantitative liquid level sensor 30 and an upper limit liquid level sensor 32 are provided. When the open / close valve 18 is opened and the chemical liquid is fed from the weighing tank 12 into the preparation tank of the main body of the automatic cleaning device via the delivery pipe 20, the lower limit liquid level sensor 28 sends all the chemical liquid in the weighing tank 12 and weighs it. It is a sensor for confirming that the tank 12 is empty. The quantitative liquid level sensor 30 is
When supplying the chemical liquid to the weighing tank 12 via the supply pipe 14, it is a sensor that senses that the liquid level of the chemical liquid has risen and almost reaches the position of the upper end opening 24 of the overflow pipe 16, and this sensor is an alarm. The worker supplies the supply pipe 1
Prepare to close the on-off valve 22 of No. 4. The upper limit liquid level sensor 28 is a sensor that issues an alarm indicating that the liquid level of the chemical liquid has gone above the upper end opening 24 of the overflow pipe 16 and warns the urgent opening / closing valve 22 to be closed.

[0006]

However, in the above-mentioned conventional chemical liquid weighing device, the chemical liquid, which is relatively expensive and causes environmental pollution, overflows by at least several tens to several hundreds of milliliters for each fixed amount. There is a problem that the pipe is discharged to the chemical liquid discharge groove. This means that the chemical liquid is wasted for each fixed amount of the chemical liquid, and if the liquid is weighed many times, the amount becomes a size that cannot be ignored. This is not desirable from an economical and environmental point of view, because not only the chemical liquid is wasted but also the capacity of the wastewater treatment facility downstream of the drainage groove needs to be increased. Further, when the opening / closing valve 22 of the supply pipe 14 is manual, if the closing operation of the opening / closing valve 22 is delayed, a larger amount of the chemical liquid flows out to the chemical liquid discharge groove via the overflow pipe. Further, when the opening / closing valve 22 of the supply pipe 14 is provided with an automatic closing mechanism that is automatically closed in association with the detection of the upper limit liquid level of the upper limit liquid level sensor 28, the opening / closing valve is erroneously operated due to a malfunction of the automatic closing mechanism. There is a problem that 22 is not closed but remains open, and therefore a large amount of chemical liquid flows out to the chemical liquid discharge groove via the overflow pipe.

In view of the above problems, it is an object of the present invention to provide a liquid weighing device that does not require the discharge of liquid, and to provide an automatic cleaning device equipped with such a liquid weighing device. is there.

[0008]

In order to achieve the above object, a liquid weighing apparatus according to the present invention is a liquid in which a liquid measured by a positive displacement weighing tank equipped with an overflow pipe is supplied to a desired place. In the weighing device, a receiving tank arranged between the upper end opening of the overflow pipe and the bottom of the weighing tank to receive the liquid flowing out from the overflow pipe, and the communication between the receiving tank and the weighing tank,
It is characterized in that it has a communication pipe with an on-off valve, and an overflow pipe penetrates a side wall of the weighing tank and is connected to the receiving tank.

The liquid weighing apparatus according to the present invention can be applied regardless of the kind of liquid to be weighed. The receiving tank used in the present invention is a normal liquid container, and may be an open type container having an open upper part or a closed type container having an upper part closed. The open type container has an advantage that the supply state of the liquid can be visually checked when the liquid is weighed, and the closed type container has an advantage that foreign matter can be prevented from being mixed. The receiving tank requires a volume larger than the volume of the liquid flowing out of the weighing tank via the overflow pipe in one liquid weighing. In order to prevent the siphon phenomenon, it is desirable that the overflow pipe extends horizontally from the upper end opening and penetrates the side wall of the weighing tank.

Further, the cleaning apparatus according to the present invention is a cleaning apparatus having a chemical solution weighing device adapted to supply a cleaning chemical solution, which is quantified by a positive displacement weighing tank equipped with an overflow pipe, to a cleaning tank. , A receiving tank arranged between the upper opening of the overflow pipe and the bottom of the weighing tank to receive the chemical liquid flowing out of the overflow pipe, and a communication with an on-off valve for communicating the receiving tank with the weighing tank And an overflow pipe penetrating the side wall of the weighing tank and connected to the receiving tank. The cleaning apparatus according to the present invention comprises a chemical liquid weighing device and a cleaning device main body, and the cleaning device main body excluding the chemical liquid weighing device is a known cleaning device and does not require any particular explanation.

In a preferred embodiment of the present invention, when the liquid level sensor provided in the receiving tank detects that the liquid level in the receiving tank reaches the upper limit, the supply of the chemical liquid to the weighing tank is stopped and the communicating pipe is further connected. It is characterized in that the provided on-off valve is automatically closed by the timer.

[0012]

In the present invention, the receiving tank temporarily receives the liquid flowing out from the weighing tank via the overflow pipe. The liquid is quantified in the weighing tank, then discharged from the weighing tank, and when the weighing tank is empty, the on-off valve of the delivery pipe is closed, then the on-off valve of the communication pipe is opened, and the receiving via the communication pipe is performed. Transfer the overflowed liquid in the tank to the weighing tank by gravity. As a result, it is not necessary to flow the overflowed liquid to the drain, the liquid is not wasted, and the liquid is not discharged. Therefore, the capacity of the wastewater treatment device downstream of the drain can be reduced accordingly.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail based on embodiments with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the configuration of an embodiment of a liquid weighing apparatus according to the present invention. The liquid weighing device (hereinafter, abbreviated as device) 10 of the present embodiment is
A conventional liquid weighing device shown in FIG. 2 has a weighing tank 12 formed of a closed vertical cylindrical container, a supply pipe 14 having an opening / closing valve 22, an overflow pipe 16, and a delivery pipe 20 having an opening / closing valve 18. , A lower limit liquid level sensor 28 and a fixed amount liquid level sensor 30. The quantitative liquid level sensor 30 operates when the liquid level rises to a position slightly lower than the position of the upper end opening 24 of the overflow pipe 16, and indicates that the liquid level in the weighing tank 12 has reached the set liquid level. It is supposed to send an alarm with. Open / close valve 2 of supply pipe 14
2 is closed by the operation of the timer 23 after a lapse of a predetermined time since the quantitative liquid level sensor 30 operates. Furthermore, the device 10
In the above, the receiving tank 40 provided near the outside of the side wall of the weighing tank 12 and the communication pipe 44 that includes the opening / closing valve 42 and connects the receiving tank 40 and the weighing tank 12 are provided. If necessary, the weighing tank 12 and the upper plate of the receiving tank 40 may be
An air vent tube (not shown) is provided.

The receiving tank 40 is a closed vertical cylindrical container for receiving the overflowed liquid through the overflow pipe 16, and is lower than the upper opening 24 of the overflow pipe 16.
The bottom plate 48 of the receiving tank 40 is arranged in a relative height relationship such that it is positioned higher than the bottom plate 50 of the weighing tank. The overflow pipe 16 has an upper opening 26 at the weighing tank 12.
It is located inside, extends horizontally, penetrates the side wall of the weighing tank 12 and descends, and the lower end opening 26 is located inside the receiving tank 40. The position of the upper end opening 26 is determined according to the weighing volume of the liquid, and when the liquid overflows from the overflow pipe 16, the overflow pipe 16 is adjusted so that the amount of the liquid stored in the weighing tank 12 becomes exactly a predetermined amount. The position of the upper end opening 24 is defined. Communication pipe 44 is receiving tank 4
The open / close valve 42 connected to the side wall of the weighing tank 12 from the bottom plate 48 of No.
It is closed by the action of 2.

Hereinafter, a method of using the device 10 will be described with reference to FIG. First, the open / close valve 18 of the delivery pipe 20 and the open / close valve 42 of the communication pipe 44 are closed, and the open / close valve 22 is opened to introduce the liquid from the supply pipe 14 into the weighing tank 12. When the liquid level of the weighing tank 12 rises to the operating position of the quantitative liquid level sensor 30, the quantitative liquid level sensor 30 operates. When a predetermined time has passed after the operation of the quantitative liquid level sensor 30, the timer 2
3 operates to close the on-off valve 22 and the liquid supply is stopped. Here, the predetermined time is a time for the liquid to reliably flow out through the overflow pipe 16 to the passage receiving tank 40 after the quantitative liquid level sensor 30 operates, and is generally about several seconds. As a result, the predetermined amount of liquid is accurately quantified.
Alternatively, a receiving tank liquid level sensor 46 for detecting the upper limit level of the liquid to be received is provided in the receiving tank 40, and when the receiving tank liquid level sensor 46 detects that the liquid level reaches the upper limit, the supply pipe 14
It is also possible to close the on-off valve 22 and stop the liquid supply. The liquid flowing out through the overflow pipe 16 is received in the receiving tank 40 and is temporarily stored.

After weighing, the on-off valve 18 is opened and the liquid quantified in the weighing tank 12 is put into a desired container, for example, a washing water preparation tank of an automatic washing device. After the lower limit liquid level sensor 28 operates to confirm the completion of the liquid addition, the on-off valve 18 is closed. Next, the on-off valve 42 is opened and the height difference between the receiving tank 40 and the weighing tank 12 is used to allow the liquid retained in the receiving tank 40 to flow through the communication pipe 44 to the weighing tank 12.
Transfer to. After the elapse of a predetermined time, the opening / closing valve 42 is closed by the operation of the timer 52. As a result, the device 10
Is ready for the next liquid weighing. The time set in the timer 52 is a time sufficient for the liquid in the receiving tank 40 to be completely transferred, and is previously obtained by experiments or the like. As described above, by using the present apparatus 10, the liquid can be weighed without causing the liquid to flow out to the outside as in the conventional case. In FIG. 1, arrows indicate the flow of liquid.

In the present embodiment, the opening / closing operation of the opening / closing valve 18 is manual, but it may be automatically opened / closed. For example, after the opening / closing valve 22 is closed and a predetermined time has elapsed, the opening / closing valve 18 is opened by the operation of a timer provided separately to deliver the liquid in the weighing tank 12 to a desired container, and the operation of the lower limit liquid level sensor 28. The on-off valve 18 is closed in conjunction with.

By incorporating the present apparatus 10 shown in FIG. 1 into an automatic cleaning device as a measuring device for a chemical liquid, an automatic cleaning device which does not waste the chemical liquid can be realized.

[0019]

According to the present invention, the liquid flowing out through the overflow pipe is temporarily received in the receiving tank, and the received liquid is transferred to the weighing tank again, so that the liquid is not wasted and economical. It is possible to realize a liquid weighing device that can weigh liquid. Further, since it is not necessary to discharge the liquid when weighing the liquid, it is possible to reduce the capacity of the wastewater treatment facility provided downstream of the drainage channel through which the liquid flows. In addition, by incorporating the liquid weighing device as a chemical liquid weighing device into the automatic cleaning device, it is possible to realize an automatic cleaning device that does not need to wastefully discharge the chemical liquid.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of a liquid weighing apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a conventional liquid weighing device.

[Explanation of symbols]

 10 Example of Liquid Weighing Apparatus According to the Present Invention 12 Weighing Tank 14 Supply Pipe 14 16 Overflow Pipes 18, 22, 42 Open / Close Valve 20 Delivery Pipe 23 Timer 24 Upper End Opening of Overflow Pipe 26 Lower End Opening of Overflow Pipe 28 Lower Limit Liquid Level Sensor 30 quantitative liquid level sensor 40 receiving tank 44 communication pipe 46 receiving tank liquid level sensor 48 receiving tank bottom plate 50 weighing tank bottom plate 52 timer

Claims (3)

[Claims] 1. A liquid weighing device adapted to supply a liquid measured in a positive displacement weighing tank equipped with an overflow pipe to a desired location, the liquid weighing device being arranged between an upper opening of the overflow pipe and a bottom of the weighing tank. A receiving tank adapted to receive the liquid flowing out from the overflow pipe, and a communication pipe with an opening / closing valve for communicating the receiving tank and the weighing tank, the overflow pipe penetrating a side wall of the weighing tank A liquid weighing device, characterized in that it is connected to. 2. A cleaning device having a chemical liquid weighing device adapted to supply a cleaning chemical liquid quantified by a positive displacement weighing tank equipped with an overflow pipe to a cleaning tank, wherein the chemical liquid weighing device has an upper end opening of the overflow pipe. And a bottom portion of the weighing tank, the receiving tank adapted to receive the chemical liquid flowing out from the overflow pipe, and a communication pipe with an on-off valve for communicating the receiving tank and the weighing tank with each other. A washing device, wherein a pipe is connected to the receiving tank by penetrating a side wall of the weighing tank. 3. When the liquid level sensor provided in the receiving tank detects that the liquid level in the receiving tank reaches the upper limit, the supply of the chemical liquid to the weighing tank is stopped, and the on-off valve provided in the communication pipe is further provided. The cleaning device according to claim 2, wherein the cleaning device is automatically closed by a timer.