External cleaning

Tube holes cannot be drilled very close together, since this may struc-tually weaken the tube sheet. The shortest distance between two adjacent tube holes is called the clearance. Tubes are laid out in either square or triangular patterns as shown in Figure S-.i. The advantage of square pitch is that the tubes are accessible for external cleaning and cause a lower pressure drop when shell-side fluid flows perpendicularly to the tube axis. The tube pitch is the shortest center-to-center distance between adjacent tubes. The common pitches tor square putienis arc i-in. OD on... 

Tubes are commonly laid out on a square pattern or on a triangular pattern, as shown in Fig. 15-5. Although a square pitch has the advantage of easier external cleaning, the triangular pitch is sometimes preferred because it permits the use of more tubes in a given shell diameter. Table 7 indicates the... 

Monthly external cleaning and inspection. This will uncover any leaks which can then be repaired. 

PLE is used in many food and feed applications for the analysis of a great variety of POPs. One reason for this is the acceptance of this technique by the US EPA in Method 3545 (50). A classic PLE approach involves extraction of the contaminants together with the lipid fraction, which is removed by external clean-up. Already in 1997, Schantz and co-workers (51) evaluated this technique for the extraction of OCPs and PCBs in certified reference materials (CRMs)... 

By means of external mechanical systems rinsing the liquids (sample or reagent) outside the probe, which must therefore have a position for such a purpose. Some workers use external cleaning systems combining pressurized washing and subsequent mechanical sweeping. 

Space should be provided in oradjacentto receival areasforthe temporary storage of received goods whilst they are recorded, examined and, where necessary, externally cleaned. 

ACL/Staticide s Anti-static Foam Cleaner for Glass Plastic is specially formulated for general external cleaning of computer hardware, glass and plastic materials/machines in the office and home. Leaves no film while keeping equipment clean and static free. 

All metals, with the exception of gold, form natural oxides. In many cases, the metal oxide is stripped during the external cleaning process and the small amount that is reformed after cleaning is removed by in situ cleaning in the deposition system. If the natural oxides on the surface are not removed, the depositing film material should be an oxygen-active material since the deposition is really onto an oxide surface. 

The substrate surface can be cleaned in the deposition system by several means. This in situ cleaning is intended to remove the small amount of contamination that will have developed since the external cleaning process was performed - it is not intended to replace external cleaning One technique is to cleave, fracture, or scrape the material to prepare a new surface under well controlled conditions. To obtain an atomically clean surface in ultrahigh vacuum can sometimes take weeks. 

The condition of the ambient external to the deposition environment has a major impact on how much contamination is introduced into the deposition chamber. It is important that this environment be controlled to the necessary level. This includes handling and storage of all the supplies used in the external cleaning and preparation processes as well as the cleaned substrate surfaces. 

Cleaning, external (cleaning) Cleaning done externally to the deposition chamber. 

Cleaning, plasma (cleaning) Cleaning done using an inert or reactive gas plasma either as an external cleaning process in a plasma cleaner or as an in situ cleaning process in the deposition system. See also Glow bar. 

External cleaning (cleaning) Cleaning external to the deposition system. 

Because of the harsh sun, water, wind, and salt conditions these tanks are exposed to, damage to paint often results, thus reducing usable life. Consequently, these tanks constantly require both internal and external cleaning, wall inspection, and repairs. 

This chapter presents the design of a mobile robot for externally cleaning tanks ofhydrocarbons and hydrocarbon derivatives by removing paint and corrosion from external tank walls by means of high pressure techniques like sandblasting, hydroblasting and hydrosandblasting. 

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