JPH03151577A - Cryopump - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a adsorption and shorten the time required for regenerating adsorbing material by attaching cloth activated carbon adsorbing uncondensable gas to a condensing device stored in a casing and cooled by a compressed refrigerant, and connecting the activated carbon to a power source. CONSTITUTION:A pump 1 includes a condensing device 7 which is cooled by a refrigerant cooled by a refrigerator unit 6 and which is disposed inside a casing 5 connected via a flange portion 4 to a frame body 3 having a vacuum chamber 2. The condensing device 7 comprises a pipe 10 through which the refrigerant is allowed to flow, and a cryopanel 11 mounted to the pipe 10. The cryopanel 11 is formed by stacking of numerous umbrella-shaped plates 12 on one another. In this case, the plates 12 are stuck together by cloth activated carbons not shown in the figure. The cloth activated carbons are connected in series to each other and have both ends connected to a power source. Generation of dust due to peeling of adsorbing material is thus restrained.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to a cryopump that achieves a high vacuum with a condensing device having a cooling wall that captures gas by condensation and an adsorbent that captures gas by adsorption. Regarding improvements.

(b) Conventional technology A conventional cryopump is, for example,
The structure is as shown in the publication. here,
A conventional example will be explained with reference to this publication. In FIGS. 3 and 4, in an exhaust enclosure 50 (of which only a portion of the wall 51 is shown) is arranged a talion pump body formed by a partitioning device 53 consisting of a number of longitudinal partitions 52. The partitions 52 extend between the end partitions 54,55 in an arrangement of polygonal contours. The partition 52 is mounted about a longitudinal axis defined by a projection 56.57 which engages in a pivot bearing provided in the end partition 54.55. A ring 5 is provided below the end partition 54.
8 is mounted for rotation in the circumferential direction, the ring being rotated by a linkage 6° which passes through the enclosure wall 51 by means of a sealing connection 59. The ring 58 is fixed to a circumferentially pivoting portion 61, which portion is connected to the hinge link 6.
2 to each partition 52.

According to this, by pulling the link mechanism 60 in the direction of the arrow f1 starting from the fully open position shown in FIG.
, a circumferential rotational movement occurs in the direction of , and said traction also causes a rotational opening movement via the hinge link 62 to separate the confined area enclosed by the partition 52° 54.55 and the enclosure 50 in the closed position. Extensive communication with the rest occurs.

The partition 52 has the characteristic properties of a metal and is preferably made of a thermally conductive metal. It is coated on one side with a layer 63 of adsorbent material, typically formed of activated carbon or zeolite particles adhered to or embedded in the metal surface. 20" to allow cooling elements such as welded tubes to cool the partition 52. The interior surfaces of the partition 52 and these layers of adsorbent material 63 provide a wall for trapping by adsorption. The outer surface 64 of the same partition 52 formed and without adsorbent forms a wall for trapping by condensation.

In a cryopump of this construction, the helium-cooled partition 52 is placed in the closed position, condensable gas is condensed and captured by the non-adsorbing outer surface 54 of the partition 52, and the partition 52 is then placed in the open position so that the layer 63 of adsorbent material The non-condensable gas is adsorbed and captured by the adsorbent material layer, so that the condensable gas is not adsorbed to this layer of adsorbent material and the exhaust capacity of the non-condensable gas is not reduced.

(c) Problems to be Solved by the Invention However, since the adsorbent material layer 63 is attached to one side of the partition 52 by adhering or embedding activated carbon or zeolite particles, the adsorption area is insufficient and exhaust gas is not sufficient. There have been problems such as not being carried out properly, regeneration taking time, and the life of the cryopump being shortened due to generation of coal dust due to detachment of the adsorbent.

This invention solves the above problems, and aims to provide a cryopump that improves adsorption efficiency and shortens regeneration time.

(d) Means for Solving the Problems This invention includes a casing connected to a device forming a high vacuum chamber, and a refrigerant housed in the casing and cooled to an extremely low temperature by a refrigerant compressed by a refrigerator unit. In a cryopump equipped with a condensing device, cloth-like activated carbon for adsorbing non-condensable gas is attached to the condensing device, and the cloth-like activated carbon is connected to a power source.

(f) Effect By having the above structure, this invention forms an adsorption layer in the condensing device using cloth-like activated carbon that is difficult to peel off, and also allows electric current to flow through the cloth-like activated carbon to increase the exhaust capacity. In addition to shortening the exhaust time, the cloth-like activated carbon directly generates heat to shorten the regeneration time.

(f) Examples The present invention will be explained below based on the examples shown in FIGS. 1 and 2.

Reference numeral 1 designates a cryopump, which includes a casing 5 that can be connected via a flange 4 to a frame 3 having a high vacuum chamber 2, and a refrigerant housed in the casing and cooled by a refrigerator unit 6. The casing consists of a condensing device 7 that is cooled to an extremely low temperature, and a radiation shield 8 that blocks radiant heat from the outside between the condensing device and the casing. A baffle plate 9 is attached to the radiation shield 8 on the entrance side. The condensing device 7 is composed of a vibrator 10 through which a refrigerant flows, and a taliopanel 11 attached to this pipe. This taliopanel is formed by stacking a plurality of umbrella-shaped plates 12. As shown by the hatching in FIG. 2, a cloth-like activated carbon 13 woven from fibrous activated carbon is attached to this umbrella-like plate.

Reference numeral 14 denotes a connecting line made of enameled wire or the like, which connects the cloth-like activated carbon 13 in series and connects both ends to a power source 15.

A mechanical vacuum pump 16 is attached to the frame 3 to create a high vacuum in the chamber 2 and the inside of the casing 5 to a vacuum of 10-I torr in advance.

In the cryopump constructed in this manner, the chamber 2 of the frame 3 and the inside of the casing 5 are first evacuated to a pressure of 10-')--le by the vacuum pump 16. Next, the cryopanel 10 is cooled to 15°K by the vibrator 9 through which refrigerant such as helium, which has been fully compressed by the refrigerator unit 6, flows, and the radiation shield 8 is cooled to 80°K by the refrigerant before flowing into the vibrator 9. be done. The baffle plate 9 condenses and captures water vapor, carbon dioxide, etc. in the residual gas. In addition, the cryopanel 11 condenses and captures condensable gases such as nitrogen and carbon gas, and captures non-condensable gases such as helium, hydrogen and neon by adsorbing them with cloth-like activated carbon 13. Chamber 2 is kept at a high vacuum of 10-' Torr.

The cloth-like activated carbon 13 is an umbrella-shaped plate 12 of the cryopanel 11.
By bonding the cryopanel 11 to the cryopanel 11, it is possible to reduce the generation of coal dust and increase the effective surface area. Therefore, the condensing device 7 can increase the exhaust speed of the residual gas in the chamber 2.

Moreover, by forming the cloth-like activated carbon 13 by weaving fibrous activated carbon, the fibers come into contact with each other, making it easier for current to flow throughout. During regeneration, the cloth-like activated carbon 13 generates heat by supplying power from the power supply 15 through the connection line 14, so that the gas condensed or adsorbed on the cryopanel 11 can be quickly released, and the exhaust capacity is increased. This helps speed up recovery.

In this invention, a cloth-like activated carbon 13 is bonded to a cryopanel 11, and a current is passed directly through the cloth-like activated carbon, thereby improving the ability to adsorb non-condensable gases.

(G) Effects of the Invention As described above, according to the present invention, the cloth-like activated carbon is attached to the condensing device and the cloth-like activated carbon is connected to the power source, thereby suppressing the generation of coal dust due to peeling and making it non-contactable. In addition to increasing the adsorption capacity of condensable gases, current flows directly through the cloth-like activated carbon, which speeds up the release of adsorbed gases during regeneration.
This can speed up the recovery of exhaust capacity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a cryopump showing an embodiment of the present invention, FIG. 2 is a front view of the same cryopanel, FIG. 3 is a partially exploded perspective view of a cryopump in the initial pumping stage showing a conventional example, and FIG. FIG. 4 is a perspective view of the cryopump in the final evacuation stage. 1... Cryopump, 2... Chamber, 3...
Frame body, 5... Casing, 6... Refrigerator unit, 7... Condensing device, 11... Cryopanel unit 13... Cloth-like activated carbon, 14... Connection line, 15... power supply. Figure 1

Claims (1)

[Claims] 1. A cryopump equipped with a casing connected to a device forming a high vacuum chamber, and a condensing device housed in the casing and cooled to an extremely low temperature by a refrigerant compressed by a refrigerator unit. A cryopump characterized in that a cloth-like activated carbon for adsorbing non-condensable gas is attached to the device, and the cloth-like activated carbon is connected to a power source.