JPH07293500A - Vacuum exhaust device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a vacuum exhaust device using an oil diffusion pump that does not cause backflow of oil during a power failure. [Composition] A gas injection nozzle mounted toward the jet part of the oil diffusion pump, and an electrically closed valve provided in the middle of the pipe for sending the cooling gas to the gas injection nozzle are provided. Allow cooling gas to be ejected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum exhaust device using an oil diffusion pump.

[0002]

2. Description of the Related Art Oil diffusion pumps are used in various fields as a vacuum exhaust device for medium and high vacuum.

FIG. 2 shows a conventional vacuum exhaust device using an oil diffusion pump. In the figure, reference numeral 1 is a vacuum container for forming a vacuum inside a vacuum chamber of an analyzer, and 2 is an oil diffusion pump attached to the vacuum container 1. The oil diffusion pump 2 ejects the boiler portion 2a which turns the oil contained in the case into an oil vapor by heating it with a heater H, and the oil vapor generated above the boiler portion 2a. It is composed of a jet portion 2b which produces a vacuum exhaust action.
A cooling fan 3 is attached near the case of the jet portion 2b so as to face the jet portion 2b, and the jet portion 2b is cooled by air cooling.

Reference numeral 4 denotes a power source for supplying electric power to the heater and the cooling fan 3 of the boiler section 2a of the oil diffusion pump, and a commercial power source is generally used. A switch indicated by 5 is provided in the power supply line to the heater of the boiler section 2a,
A timer switch 6 is provided in the power supply line of the cooling fan 3. When this switch 5 is turned on, the timer switch 6 is turned on in conjunction with it. Also, the timer switch 6 is kept in the ON state for a certain period of time (for example, about 15 minutes) after the switch 5 is turned off, and then the timer switch 6 is delayed in OF.
It is set to be F.

When performing vacuum evacuation by the vacuum evacuation device using the oil diffusion pump as described above, the switch 5 is activated to heat the boiler section 2a and drive the cooling fan 3 to cool the jet section 2b. Thus, the oil vapor is prevented from flowing back into the vacuum container 1. When the boiler portion 2a is heated to a sufficiently high temperature to generate oil vapor, the inside of the vacuum container 1 is evacuated. However, it is a matter of course that an auxiliary pump such as an oil rotary pump (not shown) is provided on the exhaust port side of the oil diffusion pump to perform auxiliary exhaust, or the vacuum container is preliminarily exhausted to a low vacuum region. To do.

During evacuation, the cooling fan 3 is energized at the same time as the heater H of the boiler part 2a, and the outer case of the jet part 2b is air-cooled, so that the oil vapor inside the jet part 2b is cooled to produce a vacuum. The oil vapor that has finished the exhausting action is condensed again to be in a liquid state and is returned to the boiler portion 2a.

When the vacuum exhaust is finished, the switch 5 of the oil diffusion pump 2 is turned off to stop the heating of the heater H. Even if the heater H is stopped, the boiler part 2a is still at a high temperature for a while, so that the cooling fan 3 needs to be continuously driven for a while after that because oil vapor continues to be generated. Therefore, at the same time when the switch 5 is turned off, the timer switch 6 starts clocking, the cooling fan 3 is kept energized for a predetermined time to continue air cooling, and the timer switch 6 is turned off after cooling until no oil vapor is generated. It is designed to be.

FIG. 3 is a diagram of a vacuum exhaust device using another conventional oil diffusion pump. This oil diffusion pump uses a water-cooling method for cooling the jet portion 2b, and the water-cooling pipe 2c is fixed by solder so as to be wound around the outer case outer periphery of the jet portion 2b, and is cooled by water through the cooling water channels 7a and 7b. By supplying the cooling water from the cooling water circulation device 7 to the pipe 2c, the jet portion 2b is cooled. Also in this example, even if the heater H of the boiler part 2a is turned off, the cooling water circulation device is kept in the ON state for a while and the cooling water continues to flow, and after the boiler part 2a is sufficiently cooled, the cooling water circulation device is 7 is stopped.

[0009]

In such a conventional vacuum exhaust apparatus, when a power failure occurs (when a power source other than the commercial power source is used and the power source fails or the power supply is stopped). In addition, the cooling fan or the cooling water circulation device is stopped at the same time as the heater of the boiler part of the oil diffusion pump is stopped. Even if the heating of the heater is stopped by stopping the power supply,
Since the temperature of the boiler is high for a while, oil vapor continues to be generated. However, since the cooling fan or the cooling water circulation device is stopped, the jet portion is not cooled, so that the temperature of the jet portion rises and the oil vapor is not condensed. Therefore, the oil vapor flows back from the oil diffusion vacuum pump to the upper vacuum container, and the vacuum container is contaminated with oil.

The present invention has been made to solve such a problem, and even if the power supply is stopped due to a power failure or the like, the vacuum container is not contaminated and it is necessary to perform maintenance work after the power failure is restored. It is an object to provide a vacuum exhaust device.

[0011]

The vacuum evacuation device of the present invention, which has been made to solve the above problems, is directed to a jet portion of an oil diffusion pump in a vacuum evacuation device for exhausting a vacuum container using an oil diffusion pump. Gas injection nozzle attached by
It is characterized in that it is provided with an electrically closed valve provided in the middle of a pipe for sending the cooling gas to the gas injection nozzle, and the cooling gas is ejected from the gas injection nozzle at the time of power failure.

The operation of the vacuum exhaust device of the present invention will be described below.

[0013]

In the vacuum exhaust apparatus of the present invention, when a power failure occurs, the energizing closed type valve provided in the pipe for sending the cooling gas to the gas injection nozzle is opened and the cooling gas is ejected from the gas injection nozzle. To be done. As a result, air cooling of the jet part of the oil diffusion pump can be maintained by the cooling gas after the power failure starts, so that oil vapor does not flow back into the vacuum container or scatter from the exhaust port side to the outside of the oil diffusion pump. .

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an evacuation device showing an embodiment according to the present invention. In this figure, the same parts as those in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

In this vacuum exhaust device, the gas injection nozzle 9 is directed toward the jet flow section 2b of the conventional oil diffusion pump shown in FIG.
Is attached. The gas injection nozzle 9 is connected to a cylinder 10 as a cooling gas source by piping. Compressed air is suitable as the cooling gas, but a gas cylinder such as Ar or N2 installed near the apparatus for the purpose of using it in a vacuum container may be used together. An electrically closed valve 8 is attached in the middle of a pipe connecting the injection nozzle 9 and the cylinder 10. The energization closed type valve 8 is a line independent from these power supply lines so that it can be confirmed whether or not the power supply 4 is out of power regardless of whether the heater of the boiler part 2b or the cooling fan 3 is ON or OFF. That is, the boiler section 2b
The heater and the cooling fan 3 are connected to the power source 4 in parallel.

Next, the operation of this vacuum exhaust device will be described. When the power is on, the switch 5 is turned on to operate the vacuum exhaust device, and when it is finished, the switch 5 is turned off.
By doing so, the heater of the boiler part 2a is stopped, the timer switch 6 starts the time counting operation, and the cooling fan 3 is stopped after a lapse of a fixed time. During this period, the energization closed type valve 8 is in the closed state, so that the cooling gas is not supplied from the gas injection nozzle 9.

Next, the operation in the case of sudden power failure when the switch 5 is ON will be described. The heater H of the boiler part 2a stops with the power failure, but the cooling fan 3 also stops at the same time. On the other hand, energized closed type valve 8 simultaneously with power failure
Is opened, the cooling gas flows from the cooling gas source 10 to the gas injection nozzle 9, and the cooling gas is blown toward the jet portion 2b. Therefore, cooling is continued by the cooling gas instead of the cooling fan 3. In this state, cooling is continued until the gas in the cylinder is exhausted, and during that time, the temperature of the boiler portion 2a drops and oil vapor is not generated.
In this way, the oil can be prevented from diffusing into the vacuum container and escaping from the exhaust port.

In this embodiment, an air-cooled oil diffusion pump is shown, but a water-cooled oil diffusion pump can also be used.

Further, although the cylinder is used as the compressed gas source in this embodiment, it is not limited to this. Line nitrogen or the like may be connected in a factory or the like.

[0020]

As described above, in the vacuum exhaust apparatus of the present invention, the jet portion can be continued to be cooled by jetting the cooling gas at the time of power failure, so that the backflow of oil vapor and the scattering of oil can be prevented. Further, in the case of using the water-cooling type oil diffusion pump, it is possible to prevent the water-cooling pipe from dropping due to melting of the solder for joining the water-cooling pipe.

[Brief description of drawings]

FIG. 1 is a diagram showing a vacuum exhaust device which is an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional vacuum exhaust device.

FIG. 3 is a view showing another conventional vacuum exhaust device.

[Explanation of symbols]

 1: Vacuum container 2: Oil diffusion pump 2a: Boiler part 2b: Jet part 3: Cooling fan 4: Power supply 8: Energization closed type valve 9: Injection nozzle 10: Cylinder

Claims (1)

[Claims] 1. A vacuum evacuation device for evacuating a vacuum container using an oil diffusion pump, in the middle of a gas injection nozzle attached to a jet part of the oil diffusion pump and a pipe for sending a cooling gas to the gas injection nozzle. A vacuum exhaust device characterized in that a cooling gas is ejected from a gas injection nozzle in the event of a power failure.