Does the cooling method fail at high temperatures?
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Question: For valve bushings assembled using the cooling method, will they fail and come loose under high-temperature operation? An ultra-high pressure hydraulic control valve uses a shaft sleeve with a diameter of 80 mm. The bushing is installed in the valve body using liquid nitrogen cooling. During operation, medium-pressure steam is used to heat the valve body, while cooling water is used to cool the valve packing. At 190 degrees on the valve body, will the shaft sleeve come loose due to the increase in temperature, overcoming the interference fit of the shaft sleeve?
It’s hard. Some people say it’s like removing a bearing from a shaft; a temperature change of 190 degrees is enough to remove the bearing from the shaft. However, the fit between the bearing and the shaft is achieved through heat treatment during installation. Disconnecting after heating is the reverse process of the installation process. That makes sense. There are some differences from placing it in liquid nitrogen to cool the shaft sleeve before inserting it into the hole of the valve body.
The temperature difference between the two required during installation and removal (the difference in expansion caused by this temperature difference). . . .