Bake-out procedure

The loose water will become destructive and may cause spalling if not removed. The excess water is removed by slowly baking out the material and allowing the water vapor to slowly dissipate out of the material. This bake out procedure is called the dry-out procedure. The material is considered to be safe, and water free once the steel containment reaches 212°F. In effect if the cold face is 212°F, then all of the refraetory is at least this temperature as well. This is proof that no free water remains in the material. 

The vapor pressure of materials as well as the desorption rate of adsorbates increase with rising temperature. Therefore, once closed, UHV chambers are subjected to a bake-out procedure, that is, the whole vacuum system is heated to 150-250 °C for many hours while pumping. Likewise, filaments and the samples themselves have to be preheated to temperatures higher than in the following experiments in order to outgas unwanted contaminants (specific sample cleaning, see Section 3.1.4.1). Obviously, bake-out and outgassing temperatures put constraint on the materials that can be used for and in a UHV system. 

Procedure II. Referring to Figure 2, one sees that A is connected directly to the high vacuum manifold as before, but in addition, it is connected with the remainder of the vessels by a parallel manifold in which there is incorporated a second breakseal, 5. This arrangement allows us to isolate bake-out vessels B, C, and D completely from vessel A during the degassing operation. 

This synthesis can also be accomplished by using a column of chromium(II) chloride as a getter for a second column of the salt. A Vycor tube, 90-cm. by 13-mm. bore, baked out as described in procedure A, is used for this purpose. Sublimed chromium (III) chloride is introduced in such a way that two columns are formed, each being 10 cm. long and separated from each other by a distance of 20 cm. The materials are held in place by glass wool. Two Hoskins furnaces (hinged type) are used in line, a... 

Start heating about 12 h before beginning the experiment. Use a slow heating rate to reach a temperature well below that of the experiment. This procedure will create a well-baked-out system. 

Following the above procedures, dispose of properly scrapped acetylene cylinders in landfills that are permitted to accept industrial solid waste or otherwise identified as special waste. An option to the disposal of acetylene cylinders in landfills is the bake out of cylinders to remove the acetylene absorbent. Bake out may be available in certain areas through private or commercial arrangements. When bake out is selected, acetylene cylinders are first prepared by recovering any residual acetylene as described above. Valve removal and cylinder scrapping is done after the bake out process. These activities should be prearranged with the... 

After the construction or renovation project has been completed, other strategies fall into play that can have a major impact on the lAQ of the facility. Much has recently been written about bake-out or flush-out procedures. 

Chronological order is very important, especially when it comes to procedures. If you perform the steps out of chronological order, you won t get the results you desire. Just imagine, for example, that you are trying to bake a cake. What happens when you do things out of order You go without dessert. 

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