JPH0519589Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a low-vibration vacuum evacuation device that uses a high vacuum pump such as a cryopump to obtain a clean vacuum.

(Prior art) As a device for supporting a high vacuum pump that operates at high speed in a vibration-proof manner, the high vacuum pump is suspended from a main exhaust pipe fixed to a frame using a bellows. In addition to damping the vibrations of the pump with the bellows, in order to prevent the bellows from being compressed due to the back pressure generated when the target is evacuated, the high vacuum pump is pulled and the bellows is compressed. There is a structure in which a sealed air spring is installed between the high vacuum pump side and the high vacuum pump side.
The contents are also known from the publication No. 61-13115.

(Problem to be solved by the invention) In the above conventional example, the sealed air spring is an annular pressure bag arranged around the bellows. It has a structure in which a plurality of pneumatic cylinders are arranged equidistantly from the center of the bellows and parallel to the axis, and the piston rods of the cylinders are pressed against the air spring.

Therefore, the structure is extremely complicated and the cost is high, and a large installation space is required for installing the pneumatic cylinder around the bellows, making it difficult to achieve compactness.

From this point of view, the present invention has been devised to provide a device suitable as a general-purpose machine that has a simple and compact structure and has a remarkable effect in preventing the vibration-preventing bellows from being compressed. By adding a bellows, which has a small structure, and combining it with a pressurizing means that can be used from an attached device, it has become possible to achieve a reliable back pressure absorption effect, thereby increasing the economy and reliability of the device. The purpose of the invention is to realize sexual enhancement with a low-cost structure.

(Means for Solving the Problems) Therefore, as is clear from the attached drawings showing the embodiments, the invention of claim 1 fixes the tank 1 to the pedestal 3 placed on the floor via the vibration isolator 4. , in a vacuum evacuation device in which a high vacuum pump 2 is suspended and supported via a first bellows 5 which is installed below the tank 1 and also serves as a vacuum evacuation passage. second diameter
The bellows 6 is concentrically surrounded by the first bellows 5 to form a double bellows with an airtight space around it, and a pressurizing means 7 is provided to make the inside of the airtight space a positive pressure region. .

Further, the invention of claim 2 provides that the pressurizing means 7 is a gas branched from a high-pressure refrigerant pipe 18 connecting the compressor unit 17 and the refrigerator drive mechanism 16 of the high vacuum pump 2 and connected to the second bellows 6. Piping 19
It is preferable to use

Furthermore, in the invention of claim 3, the tank 1 is fixed to a pedestal 3 placed on the floor via a vibration isolator 4, and a first bellows 5 is installed below the tank 1 and serves as a vacuum exhaust passage. In a vacuum evacuation device in which a high vacuum pump 2 is supported so as to hang therethrough, a second bellows 6 having a larger diameter than the first bellows 5 is concentrically surrounded by the first bellows 5, and an airtight space is created around the second bellows 6. It is characterized in that it is formed into a double bellows, and the airtight space is kept in a positive pressure region equal to or higher than atmospheric pressure to seal it.

(Function) According to the invention of claim 1, while the first bellows 5 tends to contract excessively due to the back pressure from the high vacuum pump 2, the outer second bellows 6 expands to counteract this. Since the force is applied, the first bellows 5 can be used in a substantially free length state without being compressed, and as a result, vibration can be greatly reduced.

Note that by stopping the pressurizing means 7 when evacuation is stopped, it is possible to prevent overload from being applied to the first bellows 5.

Regarding claim 2, the high-pressure refrigerant, such as helium gas, in the cooling compressor unit 17, which is attached as equipment necessary for the apparatus, is transferred to the second pipe through a branch pipe.
Since it only needs to be connected to the bellows 6, the structure is simple, and as in the case of claim 1, the anti-vibration function is sufficiently exhibited, and furthermore, no additional device is required.

On the other hand, regarding claim 3, a simple means of sealing the opening while leaving it open to the atmosphere or, if necessary, supplying air slightly higher than atmospheric pressure is sufficient, and a pressurizing device is not always required. The structure is simpler as it does not require.

(Example) To explain an example below, in FIGS. 1 and 2, 1 is a tank, and a cryopump 2, which is an example of a low-temperature high vacuum pump 2 with an oil-free structure, generates a high degree of vacuum. is retained, but
This tank 1 is attached to a pedestal 3, and the pedestal 3 has four legs erected through a vibration isolator 4 and is placed on the floor.

An exhaust port (not shown) is opened at the bottom of the tank 1 attached to this frame 3, and a first bellows 5 made of stainless steel faces the exhaust port.
are hermetically connected at their upper ends.

A cylindrical casing 10 that serves as a vacuum exhaust passage is directly connected to the lower end of the first bellows 5, and the drive unit of the cryopump 2 is housed vertically in an airtight space within the casing 10. At the same time, a refrigerator drive mechanism 16 connected to the cryopump 2 is mechanically and airtightly connected to the lower end of the casing 10. In the vacuum evacuation device having such a structure, the cryopump 2 is supported by the casing 10 so as to be substantially suspended via the first bellows 5 which also serves as a vacuum evacuation passage, and the vibration of the cryopump 2 causes the first bellows 5 to expand and contract. As a result, the beam is formed so that it propagates to the pedestal 3 in a greatly attenuated state.

The cryopump 2 has a well-known structure, and includes a chevron 11 and a first panel 1 from the top to the bottom.
2, second panel 13, cylinder 14, refrigerator section 1
5 and a refrigerator section drive mechanism 16, the upper end of the drive mechanism 16 having a larger diameter than the refrigerator section 15 and the first bellows 5 are mechanically and airtightly connected.

With this configuration, it is clear that low-frequency vibrations among the vibrations generated when the cylinder 14 and the drive mechanism 16 operate are absorbed and attenuated by the second bellows 6. A second bellows 6 of the same type as the first bellows 5 is attached thereto, and the example shown in FIG.
A second bellows 6 having a larger diameter and approximately coaxial length is concentrically surrounded by the second bellows 6 to form a double bellows, and both ends of the second bellows 6 are connected to the bottom of the tank 1 and the outer surface of the casing 10. The casing 10 is supported in parallel by the first bellows 5 and the second bellows 6, while the space between the first bellows 5 and the second bellows 6 is an independent airtight space. It's summery.

A pressurizing means 7 is then connected to the airtight space to form a vibration isolator, but the pressurizing means 7 in FIG. They are connected by a discharge pipe 8, and it is preferable that this discharge pipe 8 is opened only while the cryopump 2 is operating.

By configuring it in this way, the cryopump 2
During operation, however, it is possible to maintain the airtight space between both bellows 5, 6 at an appropriate high pressure range, and while the first bellows 5 tends to contract extremely due to the back pressure of the cryopump 2, the back pressure can be offset by the expanding force of the second bellows 6, the inside of which is pressurized. Thus, the first bellows 5 is maintained in a free length state optimal for vibration absorption, and the vibration isolation function can be fully exerted.

On the other hand, the pressurizing means 7 in FIG. It is formed by a gas pipe 19 branched from a high-pressure refrigerant pipe 18 that connects to the high-pressure refrigerant pipe 18.

In this example, the function of maintaining the free length of the first bellows 5 is the same as in the example shown in FIG. No equipment is required, which has the advantage of further simplifying the structure.

Next, the example shown in FIG.
One sealable opening 9 is provided in the sealed space surrounded by 6, and after opening the opening 9 and maintaining the inside at atmospheric pressure, the opening 9 is sealed, and the sealed space is maintained in an independent airtight chamber. The structure is different from the above-mentioned two examples in that the vibration damping effect is the same. Note that, of course, the sealed space may be kept in a pressure range equal to or higher than atmospheric pressure and sealed.

(Effect of the invention) In the device according to claim 1, it is only necessary to add the second bellows 6 and to add the pressurizing means 7 for adjusting the pressure inside the bellows 6.
Only the second bellows 6 is arranged concentrically around the first bellows 5, and the device can be made more compact without taking up much installation space.

Furthermore, by adjusting the set pressure in the pressurizing means 7, the optimum conditions for preventing excessive contraction of the first bellows 5 can be determined, so that the objective can be easily and reliably achieved.

In the device according to claim 2, the pressurizing means 7 is constructed by using the positive pressure of the device provided in the vacuum evacuation device and by simply adding piping, so the structure is simpler and more compact. This has the advantage of further promoting innovation.

In the apparatus of claim 3, when the machine is first assembled, the space surrounded by the bellows 5 and 6 can be sealed while keeping the pressure in a pressure range higher than atmospheric pressure, so that the pressurizing means 7 is always required. The assembly work is simple, and the structure can be simplified.

[Brief explanation of the drawing]

1 to 3 are schematic elevational views of each embodiment of the present invention. 1... Tank, 2... High vacuum pump, 3... Frame, 4... Vibration isolator, 5... First bellows, 6...
Second bellows, 7... Pressurizing means, 16... Refrigerator drive mechanism, 17... Compressor unit, 18...
High pressure refrigerant piping, 19...gas piping.

Claims (1)

[Claims for Utility Model Registration] 1. A tank 1 is fixed to a pedestal 3 placed on the floor via a vibration isolator 4, and a first bellows 5 serving as a vacuum exhaust passage is installed below the tank 1. In the vacuum evacuation device in which the high vacuum pump 2 is suspended and supported through the first
The second bellows 6, which has a larger diameter than the bellows 5, is connected to the first bellows.
A low-vibration vacuum evacuation device characterized in that it is formed into a double bellows that surrounds the bellows 5 concentrically and has an airtight space around it, and is provided with a pressurizing means 7 that makes the inside of the airtight space a positive pressure region. Device. 2. The pressurizing means 7 is a gas pipe 19 branched from a high pressure refrigerant pipe 18 connecting the compressor unit 17 and the refrigerator drive mechanism 16 of the high vacuum pump 2 and connected to the second bellows 6. Low-vibration vacuum exhaust equipment. 3. A tank 1 is fixed to a pedestal 3 placed on the floor via a vibration isolator 4, and a high vacuum pump 2 is connected to the tank 1 via a first bellows 5, which also serves as a vacuum exhaust passage, and is installed below the tank 1. In the vacuum evacuation device supported in a suspended manner, the first
The second bellows 6, which has a larger diameter than the bellows 5, is connected to the first bellows.
A low-vibration vacuum characterized by forming a double bellows concentrically surrounding the bellows 5 and having an airtight space around it, and sealing the airtight space by maintaining it in a positive pressure region equal to or higher than atmospheric pressure. Exhaust device.