Installation points of cryopumps in cryogenic refrigerators

In the construction of the cryogenic refrigerator, the cryopump is a must. The low temperature freezer manufacturer LNEYA tells everyone that the cryopump should be operated according to the requirements when it is installed.

Installation facilities and requirements:

The foreline pump—the cryopump requires a pre-stage pump pre-vacuum chamber to draw the start-up pressure of the cryopump and to remove the gas generated during regeneration when the cryopump is regenerated.

Adsorption well—Install the water-cooled baffle. If the oil vapor returns to the cryopump, the low-temperature freezer tells you that if its adsorption array is contaminated, the adsorption array must be replaced.

High vacuum valve—installed between the cryopump and the vacuum chamber, which can shorten the start-up time, regenerate the cryopump without deflation in the vacuum chamber, and leak the vacuum chamber at any time.

Pre-pumping valve—At the pre-pumping port of the cryopump, a valve must be installed. The valve is open during pre-extraction and regeneration, and is closed during operation of the cryopump. Another one is used for The same mechanical pump pre-extracts the vacuum chamber.

Installation of compressor：

Make sure the compressor is placed on a stable level.

Static pressure – turn off the compressor and let it be at room temperature. The pressure should be between 1.4-1.5 Mpa. If the pressure indication is low, you need to add some He gas (99.999% purity).

The cooling water pipe connected to the compressor is connected to the water-cooled compressor.

Install the cryopump:

High vacuum flange connection

The cryostat Xiaobian tells you that the cryopump can be fixed in any place required by the vacuum chamber by means of its high vacuum flange. Please check whether the “O” ring is intact before installation, and the surface is free of indentation and debris. .

Connection of the suction port and the safety valve

The cryopump cannot be vented during operation, so it is necessary to pre-pump the cryopump through the suction port by using a rough pump such as a mechanical pump before starting, and it can be used as an outlet for the gas released during regeneration. Be sure to connect the pumping port of the cryopump to the pre-stage pump of the corresponding size.

Connect the cryopump and compressor

Remove the cryopump and compressor, as well as the protective caps on all self-sealing joints on the metal hose.

Note: Never use a cleaner to wipe the self-sealing joint in the following steps.

Before connecting, you must ensure that there are no dust, oil, particles, etc. on the joint. If necessary, use a brush to clean the thread. Use a soft cloth without cotton to wipe any dirt on the sealing surface.

Connect the metal hose, connect the hose according to the direction of the airflow, start from the compressor to the cryopump, then from the cryopump to the compressor, use two wrenches to tighten each self-sealing joint to protect the hose from twisting and leaking. , moderately tighten each joint. The low-temperature freezer, which is good, tells everyone that after the connection is completed, the indication of the pressure gauge of the compressor is checked. If it is 1.3 to 1.5 MPa, it is normal. If it is lower than this value, the purity is greater than 99.999% as described above. Add some more to your suffocation.

Special Note: The metal hose maintains a high pressure of 1.4-1.5 MPa, so it should be used with great care to prevent damage or reverse.