JPS63195388A - Vacuum exhaust - Google Patents

Abstract

PURPOSE:To heighten the utilization efficiency of energy by driving a vacuum pump by means of a gas turbine and making a flow-passage-connection between the exhaust opening of the vacuum pump main-body and a combustion chamber. CONSTITUTION:By rotate-driving a gas turbine 36, the rotor 24 of a vacuum pump 10 rotates and vacuum exhaust is conducted. Provided is a discharge port 46 which makes a flow passage connection through an exhaust opening 22 and a piping 44 with a combustion chamber 14 which generates combustion gas rotating the turbine 36. And, exhaust gas from the vacuum pump flows into the combustion chamber 14 through the discharge port 46. Accordingly, the utilization efficiency of energy can be heightened.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to vacuum evacuation of a reaction chamber in semiconductor manufacturing equipment, etc., especially when the exhaust gas contains a natural gas. The present invention relates to a vacuum evacuation device used for.

[Prior Art] Conventionally, in order to evacuate the inside of a reaction chamber to a high vacuum in a semiconductor manufacturing process, 1, for example, a turbo molecular pump and an oil rotary pump are combined, and these vacuum pumps are driven to evacuate the gas inside the reaction chamber. are doing. and,
The toxic and dangerous gas components contained in the gas exhausted from the reaction chamber are treated and rendered harmless by the waste gas treatment device installed behind the vacuum pump. I have to.

As a method for treating this waste gas, an absorption method using various scrubbers such as a packed column, a spray column, a venturi scrubber, a jet scrubber, a plate column, a bubble column, etc. is mainly used. In some cases, combustion methods are used to decompose flammable gas components by burning them in a flame, and in some cases, harmful gas components in waste gas are mixed with oil from oil rotary pumps, etc., to create oil mist traps. In some cases, a method of using and disposing of such materials is also used.

[Problem that the invention seeks to solve]

However, in the absorption method that is often used for waste gas treatment, the absorption rate fluctuates due to changes in temperature, and as the temperature rises, the waste gas treatment efficiency decreases. Further, it is necessary to separately process the waste liquid after absorbing harmful components. A similar secondary treatment problem occurs in a method in which oil is mixed with harmful gas components in waste gas and then disposed of. Furthermore, when using both of these methods, it is necessary to take separate safety measures for toxic and dangerous gas components that are not absorbed into the liquid or mixed with the oil. When using the combustion method, the harmful gas components in the waste gas are burned and decomposed in the flame, so if a waste treatment device is installed in the latter stage to separate combustion waste and non-combustible components, it is possible to However, it burns a large amount of fuel gas just to decompose harmful gas components1, so it has poor energy efficiency.
In conventional vacuum evacuation equipment, the vacuum pump and waste gas treatment equipment are installed separately and connected through piping, which requires a large amount of installation space and also leads to high costs. It turns out.

This invention was made in order to solve the above-mentioned problems in conventional vacuum evacuation systems that use various types of waste gas processing equipment. However, it is a technical problem to provide a vacuum evacuation device that can improve the efficiency of energy use and reduce the installation space by making the device compact.

[Means for solving problems]

The present invention provides a vacuum exhaust device including a vacuum pump main body, a turbine chamber having a gas turbine, and a combustion chamber having a combustion device and sending the high-temperature combustion gas to the turbine chamber to rotate the turbine blades. It was constructed as a thing. The vacuum pump main body is constructed of a type of vacuum pump that performs evacuation by rotating a rotor fixed to a rotary drive shaft, and the gas turbine is coaxially mounted on the same axis as the rotary drive shaft to generate the gas. The vacuum pump is driven by a turbine. Furthermore, the exhaust port of the vacuum pump body and the combustion chamber are connected through a flow path so that exhaust gas from the vacuum pump body flows into the combustion chamber.

[For production]

In the vacuum exhaust system according to the present invention configured as described above, the high temperature combustion gas after burning the fuel gas in the combustion chamber is sent to the turbine chamber, where the velocity energy of the combustion gas is converted into mechanical energy. is converted to power a gas turbine. The drive of this gas turbine rotates the rotary drive shaft of the vacuum pump body, which is coaxial with the rotation shaft of the gas turbine, which rotates the rotor, which in turn rotates the reaction chamber, etc., which is connected to the suction port side of the vacuum pump body. vacuum evacuation is performed.

The exhaust gas exhausted from the interior of the first reaction chamber and the like is discharged from the exhaust port of the vacuum pump body and flows into the combustion chamber. In this combustion chamber, toxic,
Dangerous combustible gas components are decomposed by combustion in the flame and rendered harmless, and the energy generated as a result of the combustion decomposition is used as part of the energy that drives the gas turbine.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

The figure shows one embodiment of the present invention, and is a partially sectional front view schematically showing a vacuum evacuation device.

This vacuum evacuation device includes a vacuum pump main body 10. It consists of a turbine chamber 12, a combustion chamber 14, and a waste disposal bag [16]. The vacuum pump main body IO includes a casing 18. which has an intake port 20 and an exhaust port 22. A rotor 24 rotatably disposed in the center of this casing 18, this rotor 2
A stator 26 fixed to the casing 18 adjacent to the stator 4
, a rotary drive shaft 28 . fixed to the center of rotation of the rotor 24 .
and screw seals.

It is composed of a shaft sealing portion 30 of the rotary drive shaft using a sealing means such as a seal by injecting purge gas. The vacuum pump constituting the vacuum pump body 10 is of the type that performs vacuum evacuation by rotating a rotor by rotating a drive shaft once, such as a well-known turbo molecular pump. This turbo molecular pump.

A rotor having a large number of blades around the outer periphery of a disk that is inclined in the direction opposite to the axial direction, and a stator having a large number of blades around the outer periphery of a disk that are inclined in the opposite direction to the above-mentioned blades in the axial direction. By rotating the rotor at high speed, the molecular density on the intake side is gradually made smaller than the molecular density on the exhaust side, thereby performing vacuum evacuation. However, since a turbo molecular pump will not operate unless the back pressure is approximately 0.1 to 1 * 5 T o rr or less, when using this turbo molecular pump, it is necessary to connect an auxiliary pump to the downstream side. . As this auxiliary pump, there may be used a well-known pump that rotates integrally with the rotor of a turbomolecular pump in common with the rotary drive shaft, and that is housed in the same casing. In addition, as the vacuum pump constituting the vacuum pump main body 1O, a centrifugal vacuum pump as disclosed in the specification of the patent application filed earlier by the present applicant dated February 3, 1988 may be used alone. Alternatively, it can also be used in combination with a turbomolecular pump. The centrifugal vacuum pump described in the same specification divides the inside of a cylindrical casing into a plurality of chambers by axially connecting a plurality of partition walls each having a ventilation hole formed in the center. Each disc-shaped rotor has a plurality of ventilation passages formed on its front side extending from the center in the centrifugal direction to the periphery. It consists of a conjunctiva separated by a predetermined distance from the front of the partition wall, and when the rotor rotates at high speed, centrifugal force creates a density distribution of gas molecules, and by repeating this process, a high vacuum is obtained. It is something. Furthermore, any vacuum pump other than the above may be used as long as it is a type of vacuum pump that evacuates by rotating a rotary drive shaft and rotating a rotor at high speed. Note that 32 in Figure 1 is a bearing.

The turbine chamber 12 accommodates the gas turbine 3 within the casing 34.
6 is a conjunctival structure, and the rotating shaft 3 of the gas turbine 36
Reference numeral 8 is coaxial with the rotary drive shaft 28 of the vacuum pump main body 10 described above, and by rotationally driving the gas turbine 36, the rotor 24 of the vacuum pump main body 10 rotates to perform vacuum evacuation.

The rotating shaft 38 of the gas turbine 36 is rotatably supported by a bearing device 40 at its lower end. A water cooling section 42 is attached to the outside of the casing 34, and a shaft sealing section 3 provided on the rotational drive shaft 28 of the vacuum pump main body 10
0 protection and cooling of high-temperature combustion gas for driving the gas turbine.

The combustion chamber 14 includes a gas burner and an igniter.

A combustion device (details not shown) consisting of a flame holder (flame holder), etc. is installed, and the fuel gas and high-pressure air, which are supplied separately through piping, are mixed and the mixed gas is ignited for combustion. let

The internal shape of the combustion chamber 14 is designed to ensure smooth flame propagation. The high temperature combustion gas in the combustion chamber 14 is sent to the turbine chamber 12 to rotate the blades of the gas turbine 36. A discharge port 46 is provided in the combustion chamber 14 and is connected to the exhaust port 22 of the vacuum pump main body 10 through a pipe 44, and the exhaust gas from the vacuum pump main body 10 passes through the pipe 44 to the discharge port. 46 into the combustion chamber 14. For this purpose, the discharge pressure of the vacuum pump main body 10 is always higher than the internal pressure of the combustion chamber 14. For example, by attaching a check valve to the piping 44, the vacuum pump main body 10 is
This prevents gas from flowing backwards towards the

Further, on the exhaust side of the turbine chamber 12, a waste treatment device 1, for example, a cyclone particle trap 50 is installed via a combustion gas path 48, and the waste treatment device 1, for example, a cyclone particle trap 50, is installed to remove non-combustible substances contained in the waste gas. Separate and process waste such as combustion residue of gas components. In addition to the above-mentioned waste treatment equipment, a scrubber may also be used depending on the case.

Next, the operation of the evacuation device having the above configuration will be explained. First, the gas turbine 36 is driven by a starter (not shown) that is normally used for the initial drive of the gas turbine 36, and after confirming that the pressure at the exhaust port 22 of the vacuum pump body has exceeded a predetermined pressure. , fuel gas and high pressure air are supplied to the combustion chamber 14, and the mixed gas is ignited and combusted. This high-temperature combustion gas is sent to the turbine chamber 12, and due to the velocity energy of the combustion gas, the gas turbine 3
Rotate blade 6 even faster. When the gas turbine 36 is driven in this way, the rotary drive shaft 28 of the vacuum pump main body lO, which is coaxial with the rotating shaft 38, rotates.
A rotor 24 fixed to the rotary drive shaft 28 rotates. As the rotor 24 rotates, the vacuum pump body 1
0 is.

The internal gas of the reaction chamber etc. is sucked in through the suction port 20 and the exhaust gas is exhausted through the exhaust port 22.

In this way, the evacuation process gradually progresses.
The inside of the reaction chamber etc. is evacuated. Exhaust gas from the vacuum pump main body 10 flows into the combustion chamber 14 from the discharge boat 46 through the piping 44 . The combustible gas components of the exhaust gas that has flowed into the combustion chamber 14 are completely combusted and decomposed in the flame. On the other hand, the combustion gas that has been sent to the turbine chamber 12 and whose velocity energy has been converted into mechanical energy for the gas turbine 36 is cooled by the water cooling section 42 together with the exhaust gas in which combustible gas components have been burned and decomposed. is then exhausted from the outlet of the turbine chamber 12 and passes through the combustion gas path 48 to the cyclone particle trap 50.
will be introduced in In this cyclone particle trap 50, wastes in the combustion gas are separated and detoxified gas is released.

Although the vacuum evacuation device of the present invention has the configuration described above, the scope of the present invention is not limited by the contents of the above description and drawings, and includes various modifications without departing from the gist of the invention. For example,
Unless there is a particular problem, do not install waste treatment equipment.

The combustion gas may be discharged as it is from the waste port of the turbine chamber, or the vacuum pump and gas turbine may be placed horizontally instead of vertically as in the device shown in the drawings as an example.

〔Effect of the invention〕

Since this invention is constructed and operates as described above,
When the vacuum evacuation device according to the present invention is used to perform vacuum evacuation in semiconductor manufacturing processes, etc., the waste gas processing efficiency is always maintained at a high level without fluctuations due to temperature changes, and the waste gas It is safe because the toxic and dangerous gas components are forcibly burned and decomposed at the outlet side of the vacuum pump, and there is no need to process waste liquid after waste gas treatment. Since the energy of the combustion gas produced by combustion of fuel gas for waste gas treatment is used to drive the gas turbine, which in turn drives the vacuum pump, it is expected that energy use efficiency will be high. can. In addition, since the vacuum pump, its drive source, and the waste gas treatment device can be integrally formed, the installation space and cost can be reduced in this vacuum evacuation device.

[Brief explanation of the drawing]

The figure shows one embodiment of the present invention, and is a partially sectional front view schematically showing a vacuum evacuation device. 61O: Vacuum pump main body, 12: Turbine chamber. 14... Combustion chamber, 16... Waste treatment device, 22... Exhaust port of vacuum pump body, 24... Rotor, 26... Stator,
28...Rotary drive shaft, 36...Gas turbine, 38
...Rotating shaft, 44...Piping.

Claims (1)

[Scope of Claims] 1. A vacuum pump body that rotates a rotor fixed to a rotary drive shaft to perform vacuum evacuation, a turbine chamber having a gas turbine coaxially mounted with the rotary drive shaft, and a combustion and a combustion chamber for sending the high-temperature combustion gas to the turbine chamber to rotate the turbine blades, the vacuum pump body having a flow path connected to the exhaust port of the vacuum pump body and the combustion chamber. 2. The vacuum evacuation device according to claim 1, wherein a waste treatment device is connected to the exhaust side of the turbine chamber. 3. The vacuum evacuation device according to claim 1 or 2, wherein the vacuum pump main body is a turbo-molecular pump. 4. The vacuum evacuation device according to claim 1 or 2, wherein the vacuum pump main body is a centrifugal pump. 5. The vacuum evacuation device according to claim 1 or 2, wherein the vacuum pump main body is a combination of a turbo-molecular pump and a centrifugal pump.