JPH0361033B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cryopump regeneration device.

Generally, when a cryopump exhausts a large amount of water, it is necessary to regenerate the cryopump by returning the water that has condensed inside the cryopump to liquid. The generated liquid was usually removed by vacuum evacuation using a rotary pump. However, such a vacuum evacuation method has the disadvantage that the oil in the rotary pump absorbs moisture, which deteriorates the degree of vacuum achieved by the rotary pump or causes a malfunction.

The purpose of the present invention is to eliminate such inconveniences, and in a cryopump in which a cup-shaped shield is provided on the outside of a condensation panel provided in the pump case, water is poured into the shield. A discharge port is formed to collect and discharge in one place,
A discharge path connected to the discharge port is provided in the lower part of the pump case, and the discharge path is provided with a steam discharge path and a moisture evaporation section surrounded by a heater, and the discharge path is inserted through the dry gas discharge path. It is characterized by providing a dry gas supply path connected to the source and having an ejection port opened in the shield.

An embodiment of the present invention will be described based on the drawings. In the drawings, reference numeral 1 indicates a refrigerator, 2 indicates a pump case,
Inside the pump case 2, a condensing panel 4 attached to the second stage 3 of the cold head of the refrigerator 1 and a shield 6 attached to the first stage 5 of the cold head of the refrigerator 1 are provided in two layers: inside and outside. The shield 6 is formed with a discharge port 7 that collects and discharges water accumulated inside the shield 6, and a discharge path 8 is connected to the discharge port 7 through a space inside the pump case 2. It was set at the bottom of 2. The discharge path 8 is provided with a steam exhaust path 10 opened to the atmosphere via a first valve 9, a communication path 12 connected to an atmosphere checker 11, and a moisture evaporation section 14 surrounding a heater 13. and further the second valve 15
A dry gas supply path 16 is provided through the discharge port 7 and the discharge path 8, which is connected to the dry gas source via the discharge port 7 and the discharge path 8 and has a jet port opening into the shield 6. The water that collects in the shield 6 during cryopump regeneration is
The water passes through the dry gas supply path 16 and accumulates in the evaporation section 14, and the distance between the dry gas supply section 16 and the inner peripheral edge of the discharge port 7 is equal to the distance between the dry gas supply path 16 and the shield 6. Acts to block heat conduction,
This prevents the temperature of the shield 6 from rising during operation of the cryopump. In the illustrated example, a heater 17 is also provided on the outer periphery of the pump case 2, and a roughing pump (not shown) is further connected to the pump case 2 via a third valve 18. In the figure, 19 indicates a battle.

Next, its operation will be explained.

When a cryopump condenses a lot of water and its pumping capacity decreases, the operation of the pump is stopped,
At the same time when the heaters 13 and 17 around the discharge path 8 and the pump case 2 are activated, the second valve 1 is activated.
Open 5. After confirming by the atmosphere checker 11 that the pressure inside the pump case 2 has reached atmospheric pressure, the first valve 9 of the steam exhaust path 10 is opened by a signal from the atmosphere checker 11 or manually.
When the temperature inside the pump case 2 becomes 0°C or higher,
The moisture condensed on the condensation panel 4 and the shield 6 melts into liquid, which falls from the discharge port 7 of the shield 6 to the moisture evaporation section 14 in the discharge path 8 and evaporates there. The steam accompanying this evaporation is ejected from the dry gas supply path 16 into the shield 6 and is discharged to the outside from the steam exhaust path 10 together with the dry gas flowing from the discharge port 7 to the discharge path 8. When the moisture in the pump case 2 is completely eliminated, each heater 13,
17, the first and second valves 9 and 15 are closed, and the third valve 18 is then opened to perform rough evacuation of the inside of the pump case 2, completing preparations for evacuation operation of the cryopump. do. If impurities in the liquid adhere to the valve seat of the first valve 9 that seals the steam exhaust path 10, the sealing performance will deteriorate and a predetermined high vacuum cannot be obtained. This prevents impurities from adhering to the first valve 9 and prevents the sealing performance from deteriorating. During operation of the cryopump, heat conduction between the shield 6 and the dry gas supply path 16 is interrupted, so the shield 6 is
It can be maintained at a low temperature of ~60K, and the vacuum pumping performance does not deteriorate.

As described above, according to the present invention, the water in the shield is collected in the water evaporation part of the discharge path provided in the pump case, is heated and evaporated with a heater, and the steam is ejected from the dry gas supply path into the shield. Since the dry gas is released in a gaseous state from the steam exhaust path to the outside, it is possible to eliminate the inconvenience caused by the rotary pump used in the conventional example mentioned above, and to regenerate the pump by discharging moisture in a gaseous state This prevents the sealing performance of the valve in the vapor discharge path from deteriorating, and the liquid is evaporated directly by the heater in the moisture evaporation section of the discharge path, allowing it to be discharged outside the pump in a short time, improving pump performance. It has the effect of not causing any deterioration.

[Brief explanation of drawings]

The drawing is a longitudinal sectional view of an embodiment of the invention. 2...Pump case, 6...Shield, 7...
Release port, 8...Discharge path, 10...Steam exhaust path, 1
4...Moisture evaporation section, 16...Dry gas supply path, 1
3,17...Heater.

Claims (1)

[Claims] 1. In a cryopump in which a cup-shaped shield is provided on the outside of the condensation panel provided in the pump case, a discharge port is formed in the shield to collect water in one place and discharge it. A discharge passage connected to the outlet is provided at the bottom of the pump case, a steam discharge passage and a moisture evaporation part surrounded by a heater are provided in the discharge passage, and the discharge passage is further inserted to connect to a dry gas source. A cryopump regeneration device comprising a dry gas supply path that is continuous and has a spout opening in the shield.