JPH0755341Y2 - Drainage duct for vacuum pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a structure of a water-sealed vacuum pump or a duct on the back pressure side of a wet roots blower.

[Conventional technology]

FIG. 3 shows an outline of evacuation of a zinc continuous vacuum deposition line and the like and gas purification.

Inside the vacuum device 5, the seal device 2 is installed and the vacuum pump 3 is installed.
Thus, gas is exhausted from the atmospheric pressure to the vacuum pressure required for vapor deposition through the exhaust duct 6. Since the thin plate 1 is usually subjected to reduction treatment, it is inappropriate to expose it to the air.

Therefore, the gas exhausted by the vacuum pump 3 is used by re-supplying it to the high pressure side by providing the gas purification device 4 and the fan 7 for gas circulation in the back pressure gas duct 8 on the back pressure side. In the normal gas purification device 4, dehydration and deoxidation treatments are performed.

As the vacuum pump 3, a water-sealed vacuum pump using water as a seal on the high-pressure side or a wet roots blower is often used. The gas on the back pressure side of these pumps 3 is accompanied by water for sealing, and a buffer tank for gas-liquid separation is provided before entering the gas purification device 4, and the water entrained in the gas collects in the buffer tank, so the drain duct Is provided.

A conventional buffer tank and a drainage duct installed therein are shown in FIG. 4, and the function thereof will be described with reference to FIG. In FIGS. 4 and 5, 3 is a vacuum pump, 8 is a back pressure gas duct, 9 is a buffer tank, 10 is an exhaust duct, 11 is a drain duct, 12 is a drain duct intake port, and 13 is outside air.

That is, as shown in FIG. 5 (a), the buffer tank 9
Water collects inside the drain duct as shown in Fig. 5 (b).
When the installation level of 11 is reached, the drainage is performed to the state shown in FIG. 5 (c) by the siphon action. Therefore,
It is possible to prevent outside air from entering the buffer tank 9 through the drain duct 11.

[Problems to be solved by the invention]

In the conventional drainage duct 11 of the buffer tank 9 for gas-liquid separation shown in FIG. 4, when water is accumulated and drained by the siphon action, the state becomes as shown in FIG. 5 (c). That is, the drain duct suction port 12 comes into contact with the free surface of the water, and when the water surface vibrates due to vibration or the like, the gap between the drain duct suction port 12 and the water surface is broken, and the outside air 13 flows into the buffer tank 9. there is a possibility. Oxygen in the outside air 13 raises the oxygen concentration in the gas, which may increase the load on the gas purification device 4 shown in FIG. If the load is exceeded, oxygen will enter the supply gas above the specified level, which will lead to oxidation of the thin plate, which is undesirable.

[Purpose of device]

The present invention intends to provide a drainage duct for a vacuum pump which can eliminate the above-mentioned concern about the invasion of the outside air by devising the shape of the drainage duct in the buffer tank for gas-liquid separation.

[Means for solving problems]

The present invention provides a buffer tank having a drain duct and a gas exhaust duct in the middle of a back pressure side duct of a vacuum pump using water as a seal, and the drain tank has a bent portion at a position lower than the drain duct level. A drainage duct for a vacuum pump, which has a shape and is provided with a pressure equalizing pipe between the drainage duct and the buffer tank.

That is, the present invention provides a drain duct for a buffer tank, which is provided with a bent portion for preventing outside air from entering in the middle of the drain duct, so that water can always be stored in the bent portion for a water seal. In addition, even if the water depth of the buffer tank becomes high and the water is drained by the siphon action, a pressure equalizing pipe with the buffer tank is provided in the drain duct midway to the bend so that the water can be sealed as described above. It is what

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1 and its operation will be described with reference to FIG. 1 and 2, in FIG.
The same reference numerals as those in FIGS. 5 and 5 indicate the same parts as those described with reference to FIGS. 4 and 5, and 14 is a bent portion of the drain duct bent downward from the level of the drain duct provided in the drain duct 11, Reference numeral 15 is a pressure equalizing pipe for connecting the drainage duct 11 in front of the bent portion 14 of the drainage duct and the buffer tank 9.

With the above-described structure, since water is always stored in the bent portion 14 of the drainage duct 11 as shown in FIG. 2 (a), it can be sealed from the outside air 13.

The water in the gas is separated in the buffer tank 9, and the water depth increases as shown in FIG. 2 (b).

Second when water reaches drainage duct 11 installation level
As shown in Figure (c), it is discharged to the outside of the system by the siphon action.

The pressure equalizing pipe 15 stops the drainage when the water depth reaches the upper level of the drainage duct 11 installation level as shown in FIG. 2 (d).

In the above state, water remains in the bent portion 14 of the drainage duct 11, and the seal with the outside air 13 is maintained.

Due to such an action, the outside air is stored in the buffer tank 9 due to the gas pressure fluctuation in the buffer tank 9 or the water surface fluctuation.
The fear that 13 will invade will be completely eliminated.

[Effect of device]

(1) Since the sealing with the outside air is performed by the water in the bent portion provided in the exhaust duct, there is no possibility of the outside air entering due to the pressure in the buffer tank or the fluctuation of the water surface level.

(2) When the water accumulated in the buffer tank reaches the drainage duct installation position, it is discharged to the outside from the buffer tank by the sifion action.

(3) Since the pressure equalizing pipe is provided, the water level in the buffer tank does not drop too much due to the siphon action.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram for explaining its operation. FIG. 3 is a diagram for explaining an application example of a vacuum pump using water as a seal, FIG. 4 is a diagram for explaining a relationship between a conventional buffer tank and a drainage duct, and FIG. 5 shows its action. It is a figure for explaining. 1 to 5, 1; thin plate, 2; vacuum seal device,
3; vacuum pump, 4; gas purification device, 5; vacuum deposition chamber, 6; exhaust duct, 7; gas circulation fan, 8; vacuum pump back pressure side duct, 9; buffer tank, 10; gas exhaust duct, 11; drainage Duct for use, 12; drainage duct water intake, 13; outside air, 14; duct bent portion, 15; pressure equalizing pipe.

Claims (1)

[Scope of utility model registration request] 1. A buffer tank having a drain duct and a gas exhaust duct is provided in the middle of a back pressure side duct of a vacuum pump using water as a seal, and the drain tank has a bent portion at a position lower than the drain duct level. A drainage duct for a vacuum pump, which has a duct shape and has a pressure equalizing pipe provided between the drainage duct and the buffer tank.