JPH032715Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cryopump driving device that condenses and adsorbs gas molecules on a surface cooled to an ultra-low temperature and exhausts the gas molecules.

Conventionally, this type of pump has generally been equipped with a helium refrigerator in order to form an ultra-low temperature cooling surface inside the pump, and in this case, the refrigerator is equipped with a refrigerator section in which helium is adiabatically expanded to generate a low temperature. Separate configurations have been carried out into a compressor section and a compressor section that compresses the expanded helium. The refrigerator section and compressor section include
Each of them is equipped with an electric motor to drive it, and these electric motors are equipped with a predetermined frequency when manufacturing the cryopump, and since a large amount of power is required to drive the compressor, a 5Kw electric motor, for example, is installed. Since a small amount of power is required to drive the refrigerator section, for example, a 100W electric motor is provided.

The electric motor for the refrigerator section and compressor section is 50
Hz and 60Hz power supplies are installed, but if the cryopump is operated in an area with a 50Hz power supply, the power supply will be 60Hz.
Refrigeration capacity will be reduced by approximately 20% compared to when operating at Therefore, as shown in Figure 1, the 50Hz power supply b is converted to 60Hz by a frequency converter a,
By operating the refrigerator section c and compressor section d of the refrigerator at 60 Hz, deterioration in refrigeration performance due to a 50 Hz power source is prevented.

However, even if the rating of the refrigerator section c is, for example, 100W, the rating of the compressor section d is significantly larger, for example, 5Kw, so the rating of the frequency converter a is also
There is an inconvenience that a large and expensive device of 5.5Kw or more must be used.

The present invention eliminates these inconveniences and enables 50Hz/60Hz
The purpose is to provide a device that can efficiently drive a commercial cryopump with a 50Hz power source at a low cost. 50 as an electric motor that drives each of the refrigerator section and compressor section.
Equipped with an electric motor that is compatible with power sources of commercial frequencies of Hz and 60 Hz, and the compressor section is configured to supply a larger amount of helium gas than the amount of helium gas required by the refrigerator section, The electric motor of the compressor section is directly connected to a 50 Hz power source, and the refrigerator section is connected to the 50 Hz power source via a frequency converter that converts the frequency from 50 Hz to 60 Hz.

An embodiment of the present invention will be described with reference to FIG. 2. The reference numeral 1 is a cryopump, 2 is a pump case, and 3 is a refrigerator section 4 and a compressor section 5. A helium refrigerator is shown in operation. The refrigerator section 4 includes two stages of refrigerator cylinders 6a and 6b provided inside the pump case 2, and an electric motor 7 with a rating of, for example, 100W provided outside the pump case 2. When the pistons in the refrigerator cylinders 6a and 6b reciprocate, the flexible hose 8
The helium that circulates between the compressor unit 5 and the cylinders 6a and 6b expands adiabatically, and the shield 9, buffer 10, and cryopanel 11 attached to each cylinder become extremely low temperature, condensing and condensing gas molecules. Adsorb and exhaust. The compressor section 5 is configured to supply a larger amount of helium gas than the amount of helium gas required by the refrigerator section 4. The helium compressor provided in the compressor section 5 includes:
Generally, a suitable Freon compressor is selected from commercially available Freon compressors and a modified one is used.The gas discharge amount (capacity) of a Freon compressor varies depending on the model and type, but is determined at a certain stage. For example, if expressed in terms of discharge amount per revolution, it is 10c.c./rev.
Compressors with different discharge volumes are manufactured in stages from small to large capacities, such as 15c.c./rev, 20c.c./rev, etc., and therefore, the refrigerator section 4 has, for example, 16c.c. If ./rev is required, it is customary to use a compressor with a capacity of 20c.c./rev and select one with a margin. Reference numeral 12 denotes an electric motor rated at, for example, 5 Kw, which drives the compressor section 5, and this and the electric motor 7 of the refrigerator section 4 are equipped with motors driven by power sources with commercial frequencies of 50 Hz and 60 Hz.

When the cryopump 1 set to be compatible with such 50Hz and 60Hz power sources is efficiently driven by the power source 13 with a low frequency of 50Hz, the frequency converter 14 is connected to the cryopump 1, but the present invention , the electric motor 12 of the compressor section 5 is directly connected to the power source 13, and a frequency converter 14 for converting from 50Hz to 60Hz is connected only to the electric motor 7 of the refrigerator section 4. 14 is connected to the power source 13, so that the frequency converter 14 can be small enough to correspond to the small rating of the electric motor 7 of the refrigerator section 4.

When the compressor 5 is driven by a 50Hz power supply 13, the rotation speed of the electric motor 12 decreases, and the capacity of the compressor section 5 decreases by about 20% compared to the case of 60Hz, but the gas supply capacity of the compressor As mentioned above, the refrigerator section 4
Usually, there is a margin for the required gas amount, so if only the electric motor 7 of the refrigerator section 4 is driven at 60Hz by the frequency converter 14, both the refrigerator section 4 and the compressor section 5 can be driven at 50Hz. The refrigerating capacity can be increased by the margin of the compressor section 5 compared to the case where the compressor section 5 is driven. In other words, by driving the refrigerator section 4 at 60Hz, the refrigerator section 4 can draw out and consume the excess gas of the compressor section 5, and the refrigerating capacity increases accordingly. do.

An experimental example of the device of the present invention is shown by curves A and B in Fig. 3, and curve A in the figure shows the cryopump 1.
Change in cooling temperature of refrigerator cylinder 6a, curve B
1 and 2 respectively show changes in the cooling temperature of the refrigerator cylinder 6b. Curves a and b shown for comparison show both the refrigerator section 4 and compressor section 5 of the cryopump 1 at 50Hz.
Refrigerator cylinders 6a and 6 when driven by the power source of
It shows the change in cooling temperature of b. As is clear from this experimental example, according to the device of the present invention, it takes time for one refrigerator cylinder 6a to reach 80K.
Shortened by 15%, the other refrigerator cylinder 6b
The time to reach 15K is reduced by 18%, resulting in increased refrigeration capacity.

As described above, according to the present invention, the refrigerator section and the compressor section of the cryopump are each equipped with an electric motor driven by a 50/60 Hz commercial power supply, and the compressor section is connected to the helium gas required by the refrigerator section. In a device configured to supply a larger amount of gas than the amount of gas, the electric motor of the compressor section is directly connected to a 50Hz power source, and the refrigerator section is connected via a frequency converter that converts the frequency from 50Hz to 60Hz. Since I connected it to the 50Hz power supply,
The cryopump's refrigeration capacity can be increased simply by installing a frequency converter with a low rating that is compatible with the electric motor in the refrigerator section, which has a low rating.It is possible to increase the refrigeration capacity with an inexpensive device, and the frequency converter can be made smaller. This has the effect of making installation easier.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional cryopump operating device, FIG. 2 is an explanatory diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing the refrigerating capacity of the apparatus of the present invention. 1... Cryopump, 3... Freezer, 4...
Refrigerator section, 5... Compressor section, 7, 12... Electric motor, 13... Power supply, 14... Frequency converter.

Claims (1)

[Scope of utility model registration request] The helium refrigerator of the cryopump is configured separately into a refrigerator section and a compressor section, and the refrigerator section and the compressor section are each equipped with an electric motor capable of supporting a commercial frequency power source of 50 Hz and 60 Hz. In addition, in the case where the compressor section is configured to supply a larger amount of helium gas than the amount of helium gas required by the refrigerator section, the electric motor of the compressor section may be directly connected to the compressor section.
Connect to a 50Hz power supply and turn the refrigerator section from 50Hz to 60Hz.
50Hz through a frequency converter to convert the frequency to
A cryopump drive device characterized in that it is connected to a power source.