JPS6050319B2 - Adhesive powder cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for cleaning powder from a powder handling instrument used in a containment body such as a glove box for handling radioactive materials.

Hereinafter, a glove box will be explained as an example of the enclosure.

Conventionally, cleaning with water has been the main method for cleaning powder adhering to instruments.

Since the cleaning waste liquid in the Cal glove box is considered radioactive waste liquid, dedicated waste liquid treatment equipment is required. The greater the number of washings, the heavier the burden on the processing equipment becomes. Therefore, it is required to reduce the amount of washing waste liquid as much as possible. Although there is a method of evaporating this waste liquid to dryness within a glove box, it cannot be said to be a general method because the amount of evaporation is limited because the humidity inside the glove box increases.

Further, it cannot be evaporated to dryness in a glove box where a high humidity atmosphere is avoided, as in the case of precise weighing of powder and moisture measurement. Another disadvantage of washing with water is that it requires a drying operation after washing.

Insufficient drying may actually make powder more likely to adhere. Other conventional cleaning methods include blowing away adhering powder with compressed air or vacuuming the powder with a vacuum cleaner.

Since these do not use water, the above drawbacks are eliminated, but
It cannot be used in a glove box because of the drawbacks described below. In other words, the glove box should be 30 mm away from the outside in order to prevent the radioactive materials handled inside from leaking outside.
Although air supply and exhaust are carried out to maintain a negative pressure of approximately Aq, there is a risk that this negative pressure may suddenly drop due to the blowing out of compressed air.

Furthermore, it is difficult to recover the blown powder. In the case of a vacuum cleaner, a large amount of exhaust gas is emitted into the vacuum box, which causes excessive flow of air, making it unsuitable for use in a glove box that handles powder.

Of course, it is not possible to emit this exhaust directly outside the glove box due to radioactive material management considerations. Another conventionally used method is wiping with paper, cloth, etc., but this is not suitable for cleaning uneven objects. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a device for cleaning adhered powder that can be used in a glove box and does not emit waste liquid.

That is, the present invention provides an enclosure that has an air supply and exhaust system and is managed to maintain a negative pressure with respect to atmospheric pressure, and an external filter that penetrates the enclosure. , and a gas pipe into which gas is fed at a pressure higher than atmospheric pressure (the gas fed into this gas pipe may be introduced from outside the enclosure, or it may be gas from the exhaust port of a vacuum pump, which will be described later). It's okay to be.

), a valve that opens and closes this gas pipe, and an air supply pipe that is connected to this valve and blows gas onto the object to be cleaned within the enclosure;
An exhaust pipe for discharging the gas blown onto the object to be cleaned through this air supply pipe, a filter for collecting powder contained in the exhaust gas discharged from this exhaust pipe, and a filter for collecting powder contained in the exhaust gas discharged from this exhaust pipe; The attached powder cleaning apparatus is characterized by comprising a vacuum tank that sucks in the exhaust gas, and a vacuum pump that evacuates the vacuum tank. Hereinafter, one embodiment of the apparatus according to the present invention will be described in detail using FIGS. 1 and 2.

In FIG. 1, reference numeral A indicates a glove box as an enclosure, and an air supply pipe 1 is connected to a compressed air source (not shown) outside the glove box A via a solenoid valve 2 and an air pipe 3. There is.

The solenoid valve 2 is normally closed. (Note that the solenoid valve may be located outside the glove box.) On the other hand, the exhaust pipe 4 is connected to a vacuum pump 8 via an air pipe 5, a filter 6, and a vacuum tank 7. The exhaust gas from the vacuum pump 8 is discharged into the glove box A. be done. FIG. 2 is a detailed sectional view of the air supply pipe 1 and the exhaust pipe 4 in a state in which they are brought into close contact with the instrument 11 to be cleaned.

The device 11 is an example of a load for introducing powder. In this state, the vacuum pump 8 is started. Predetermined true! When the vacuum gauge 9 detects that the air pressure has been reached, the solenoid valve 2 is opened for a short time.
The compressed air flows through the device 11 and is sucked into the vacuum tank, and at this time, the powder adhering to the device 11 is effectively washed by the high-speed airflow, and the washed powder is collected on the filter 6. After cleaning, open the solenoid valve 10 and close the instrument 11.
After returning the interior to the atmospheric pressure inside the glove box, the air supply pipe 1 and the exhaust pipe 4 are removed from the instrument 11. Filter 6
It is also possible to provide a solenoid valve between the solenoid valve 10 and the vacuum tank 7, close it only when the solenoid valve 10 is opened, maintain the vacuum in the vacuum tank, and shorten the time for the next evacuation. The higher the pressure of the compressed air, the more effective it is, but in principle, it is sufficient that the pressure is at least atmospheric pressure, which prevents the air inside the glove box from flowing backwards.

Also, non-corrosive gases other than air may be used. According to this embodiment, the cleaning effect is affected by the degree of vacuum and volume of the vacuum tank, but not by the pumping speed of the vacuum pump.

Therefore, by keeping the pumping speed low enough not to affect the negative pressure management of the glove box and not to cause excessive air flow, the above-mentioned drawbacks can be eliminated. Also, since compressed air is simply absorbed into the vacuum tank, this is also a negative
Does not affect pressure management. FIG. 3 shows cross sections of an air supply pipe and an exhaust pipe in another embodiment of the present invention.

The exhaust pipe 13 is tightly fixed to the air supply pipe 12, and when the air supply pipe 12 comes into close contact with the instrument 14 to be cleaned, compressed air blows out from the hole 15 at the tip of the air supply pipe 12, and the instrument 14 is blown out.
After cleaning, it is sucked into the vacuum tank through the exhaust pipe 13. Instrument 14 is an example of a powder container. Still another embodiment of the device according to the invention is shown in FIG.

The air supply pipe 16 is connected to a tank 19 via a solenoid valve 17 and an air pipe 18. On the other hand, the exhaust pipe 20 is connected to the air pipe 21. It is connected to a vacuum pump 24 via a filter 22 and a vacuum tank 23. The tank 19 stores compressed air produced by the compressor 25 in the glove box. The compressor discharge speed is kept low enough to avoid excessive air flow. However, this does not reduce the cleaning ability. This is because even if the discharge speed is lowered, the time required to fill the tank 19 will only become longer, and the ultimate pressure will not change. The exhaust port of the vacuum pump 24 and the suction port of the compressor 25 can also be directly connected by air piping.

In this case, even if the evacuation speed of the vacuum pump 24 and the discharge speed of the compressor 25 are increased, excessive flow of air does not occur, so that repeated operation for a short period of time is possible. As described above, the present invention is characterized in that it can be used in an enclosure such as a glove box, does not generate radioactive waste liquid or water vapor, and the cleaning powder is collected on a filter. , it becomes possible to clean adhering powder.

In the figure, reference numeral 26 is a vacuum gauge, and 27 is a solenoid valve, which operates in the same manner as described above.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a sectional view of an air supply pipe and an exhaust pipe in close contact with an object to be cleaned, and Fig. 3 is a configuration diagram showing an air supply pipe according to another embodiment of the present invention. FIG. 4 is a cross-sectional view showing the exhaust pipe in close contact with the object to be cleaned and the exhaust pipe in close contact with the air supply pipe, and FIG. 4 is a configuration diagram showing still another embodiment of the present invention. 1... Air supply pipe, 2... Solenoid valve, 3...
...Air piping, 4...Exhaust pipe, 5...
...Air piping, 6...Filter, 7...
・Vacuum tank, 8... Vacuum pump, 9...
Vacuum gauge, 10... Solenoid valve, 11... Instrument to be cleaned, 12... Air supply pipe, 13... Exhaust pipe, 14... Instrument to be cleaned, 15...hole, 16.
... Air supply pipe, 17 ... Solenoid valve, 18 ...
...Air piping, 19...Tank, 20...
・Exhaust pipe, 21... Air piping, 22... Filter, 23... Vacuum tank, 24... Vacuum pump, 25... Compressor.

Claims (1)

[Claims] 1. An enclosure that is equipped with an air supply and exhaust system and is managed to maintain a negative pressure relative to atmospheric pressure, and gas piping that is installed inside this enclosure and that delivers gas at a pressure equal to or higher than atmospheric pressure. a valve that opens and closes the gas pipe; an air supply pipe that is connected to the valve and that sprays gas onto the object to be cleaned within the enclosure; an exhaust pipe that discharges the gas that has been blown onto the object that is to be cleaned; and an exhaust pipe that discharges the gas from the exhaust pipe. A vacuum tank that sucks in the exhaust gas that has passed through the filter, and a vacuum pump that evacuates the vacuum tank. Adhesive powder cleaning equipment.