Related:
acdsee trial extension code – Best Practices Guide, acdsee 5.0 trial extension code, acdsee trial extension code. – GoToMeeting Alternative Free Edition.High-pressure flow of helium has become an important, reliable, and often essential component of many manufacturing processes. Flowing helium at high pressure and in a high-vacuum or low-pressure environment can advantageously be used in a wide variety of applications. For example, flowing helium at high pressure can be used to purge impurities and other contaminants from an interior region of a magnetic disk drive, such as the head disk assembly. Likewise, flowing helium at high pressure can be used to maintain a low pressure during a bakeout of electronic components of the disk drive. In addition, flowing helium at high pressure can be used during various manufacturing processes including, for example, etching, chemical vapor deposition, physical vapor deposition, or diffusion annealing.
In most applications, the high-pressure flow of helium is conducted through a long, thin tube or conduit, which is sealed at each end. Helium at a desired pressure is typically supplied to the conduit through one end, and the helium is allowed to flow through the conduit. Helium flowing through the conduit expands and evaporates, which creates pressure drops in the conduit and along its length. In some applications, a volume of liquid nitrogen is flowed through the conduit to cool the conduit and/or reduce the pressure of the helium flowing through the conduit.
In some applications, the helium is supplied to the conduit at the desired pressure and flows through the conduit at a constant rate. The rate of flow of helium through the conduit is set to be equal to or slightly greater than the rate of evaporation of the helium. As the helium evaporates, the pressure in the conduit gradually increases, which can cause the temperature of the conduit to increase. As the temperature of the conduit increases, its thermal expansion is greater than that of the materials of the conduit. As a result, the conduit increases in length, which changes the geometry of the flow path through the conduit and the flow rate of the helium through the conduit. Thus, the rate of flow of the helium through the conduit is not constant. Rather, the rate of flow of helium through the conduit varies in response to the temperature of the conduit.
As a result of changes in the rate of flow of helium through the conduit, the pressure of the helium in the conduit is different at various points along the length of the conduit be359ba680
Related links:
Comments