JPH0231587Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cryopump device for an electron microscope, etc., which is suspended and attached to the main body of an electron microscope.

A cryopump device consists of a pump body consisting of a valve drive unit and a displacer, and a compressor for sending compressed gas to the pump body. When installing such a cryopump device into an electron microscope, etc. If the vibrations from the cryopump device were transmitted to the electron microscope, it would be impossible to obtain a good quality image, so a structure as shown in FIG. 1 was conventionally used to prevent the vibrations from being transmitted.

In the figure, 1 is the cryopump main body, and this main body 1 includes a housing part that is directly attached to an electron microscope, a cooling part 1a that is inserted into the housing and consists of a cooling panel and a displacer, and a valve and a valve drive part. It consists of a valve drive section 1b consisting of a motor, and a bellows 1c connecting the two. This cryopump body is connected to a compressor 4 via Nycoils 2a, 2b made of synthetic resin and flexible tubes 3a, 3b for gas circulation. Compressor 4 is Nycoil 2
b. Gas such as helium sent from the main body 1 via the flexible tube 3b is compressed and sent to the pump main body 1 via the flexible tube 3a and Nycoil 2a.

With this configuration, most of the vibrations from the compressor 4 are transmitted to the electron microscope etc. via the pump body 1 because they are absorbed by the Nycoils 2a and 2b made of synthetic resin and wound into a coil. However, since the Nycoils 2a and 2b are made of synthetic resin, helium gas, which has an extremely light specific gravity, leaks out from the Nycoil wall surface, so helium gas must be replenished every 3 to 4 months. No.

Furthermore, as the degree of vacuum in the evacuated system increases, there is a phenomenon in which the valve driving section 1b is sucked into the cooling section 1a.If the bellows 1c is excessively compressed due to this suction, it may cause damage to the electron microscope, etc. Since vibrations are more likely to be transmitted to the pumped side, it is necessary to attach a weight 5 to the valve drive unit 1b to offset the suction force, which reduces the precessional vibration of the valve drive unit 1b when the cryopump is operated. A support frame 6 and a support stand 7 are required to support the weight 5 when the pump is held in place or when the pumped system is in a low vacuum. Therefore, a relatively large installation is required to attach the cryopump body to an electron microscope, etc. The disadvantage is that it requires space.

The present invention was developed to solve these conventional drawbacks, and includes a housing part attached to the electron microscope body, a cooling part inserted into the housing part, and a cooling part suspended from the cooling part by a bellows. A cryopump main body consisting of a valve drive section, a compressor for circulating gas to the valve drive section, and a vibration isolation block that also serves as a floor or is placed directly on the floor or via a vibration isolation table;
two metal pipes for gas circulation, one end of which is fixed to the vibration isolation block and the other end of which is fixed to the valve drive unit;
In order to connect the ends of each metal tube fixed to the vibration isolation block to a compressor, two flexible tubes for gas circulation are connected to the vibration isolation block, and vacuum suction from the electron microscope main body side is provided. In order to suppress compression of the bellows due to force, the valve drive section is mechanically supported by the vibration isolating block by the metal pipe. The embodiment will be described in detail, but the same components as in FIG. 1 are given the same numbers and their explanations will be omitted.

In the figure, reference numeral 8 denotes a heavy vibration isolating block made of concrete or the like, and this vibration isolating block 8 is mounted on a vibration isolating table (not shown) placed on the floor via a spring or the like that easily absorbs vibrations. ) is placed on top.
Two metal pipes 9a and 9b for passing gas are embedded within this vibration isolating block 8. These tubes 9a and 9b have a rigid metal tube 10a.
one end is welded. This tube 10a is made of copper or the like, and is bent horizontally at portion A. Further, the other end of the pipe 10a is connected to the valve driving section 1b.
is firmly connected to. Also, the tube 9b has a tube 10a.
One end of a pipe 10b similar to the above is welded, and the other end of this pipe 10b is also firmly connected to the valve drive section 1c. Furthermore, vibration isolation block 8 and compressor 4
and are connected by flexible tubes 11a and 11b made of metal bellows or the like.

With this configuration, the vibrations from the compressor 4 are reflected and absorbed by the vibration isolating block 8, so even though the metal tubes 10a and 10b are used, most of the vibrations are not applied to the cryopump body 1 side. Although it will not be transmitted anywhere, the gas circulation path from the compressor 4 to the cryopump body 1 uses metal pipes, so helium gas does not leak from the pipe wall, so helium gas must be replenished regularly. There's no need to. In addition, since the valve drive unit 1b is mechanically supported by metal tubes 10a and 10b that are firmly attached to the vibration isolating block 8 by welding or the like, the bellows 1c Since the weight 5, support frame 6, support stand 7, etc. to prevent the cryopump from being excessively compressed can be eliminated, the space required for installing the cryopump body can be reduced. .

If there is a concrete floor that does not vibrate, the vibration isolation block can also be used as a vibration isolation block.

As mentioned above, in the present invention, there is a vibration isolating block which is also served by the floor or is placed directly on the floor or via a vibration isolating table, and one end is fixed to the vibration isolating block and the other end is fixed to the vibration isolating block. two metal pipes for gas circulation fixed to the vibration isolation block, and two metal pipes connected to the vibration isolation block for connecting the ends of each metal pipe fixed to the vibration isolation block to the compressor.
The valve drive section is provided with a flexible tube for gas circulation, and the valve drive section is mechanically connected to the vibration isolating block by the metal tube in order to suppress compression of the bellows based on the vacuum suction force from the electron microscope main body side. Since it is configured to be supported, it is not only possible to suppress the transmission of vibration from the compressor to the electron microscope body, but also to prevent the valve drive unit from being sucked, without having to separately provide a support frame etc. in conjunction with the installation of the cryopump. Accordingly, it is possible to suppress the compression of the bellows and the transmission of cryopump vibrations to the electron microscope main body due to the compression, and provide a cryopump device for an electron microscope or the like that has a simple and compact structure.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a conventional device, and FIG. 2 is a diagram for explaining an embodiment of the present invention. 1... Cryopump main body, 1a... Cooling section,
1b... Valve drive unit, 1c... Bellows, 2a, 2
b...Nikoil, 3a, 3b, 11a, 11b
... Flexible tube, 4 ... Compressor, 5 ... Weight, 6 ... Support frame, 7 ... Support stand,
8... Vibration isolation block, 9a, 9b, 10a, 10
b...Metal tube.

Claims (1)

[Scope of utility model registration request] A cryopump body consisting of a housing part attached to an electron microscope body, a cooling part inserted into the housing part, and a valve driving part suspended from the cooling part by a bellows, and circulating gas to the valve driving part. a vibration isolating block which is also served by the floor or is placed directly on the floor or via a vibration isolating table, one end of which is fixed to the vibration isolating block and the other end of which is fixed to the valve driving section. two metal pipes for gas circulation, and two flexible tubes for gas circulation connected to the vibration isolation block in order to connect the ends of each metal pipe fixed to the vibration isolation block to the compressor. In addition, in order to suppress compression of the bellows based on the vacuum suction force from the electron microscope main body side, the valve driving section is mechanically supported by the vibration isolating block by the metal tube. Cryopump equipment such as electron microscopes.