Seal Fittings Installation

When seal fittings are installed, certain mechanical practices must be followed. The following requirements are often overlooked by both installers and inspectors ... 

FIGURE 3.56 Illustration of the quick-connect fitting for installation of capillary columns (a) internal sealing mechanism and (b) sealing mechanism inserted into fitting and locked into place (photographs courtesy of the Quadrex Corp.)... 

Blue White 20 No additional intumescent seals need to be fitted when installed. 

Steel forged fittings with screwed ends may be installed without pipe dope in the threads and seal-welded (Fig. 10-130) to secure bubble-tight joints with a minimum of welders labor. They are not subject to deformation by pipe wrenches, and such couplings, bushings, and plugs are often used with the screwed fittings below. 

If the hub removal is necessary, such as required on compressor with non-split seals, a tapered hub fit on the shaft should be used. The removable hubs should have tapped puller holes. The shaft should be keyless with the preferred method of installation and removal by use of hydraulic dilation. Two injection ports 180° apart should be used whether injection is through the shaft or through the hub. Shrink fits should be 2 to 2.5 mil/in. of diameter. API 671 rcL ommends 1,5 mil/in. minimum, but experience indicates the heavier shrink may be required. For the juncture rating calculation, a f ra lion value of. 12 is recommended. 

In order to process larger quantities of coal, an extraction reactor was constructed. The extractor was essentially a standing metal cylmder sealed on the bottom, approximately 30 cm in diameter and 84 cm in length. An electrical belt-driven stirring mechanism was fitted through the top of the reactor to provide mixmg, and three elechical band heaters were wrapped around the outside to supply process heat. A water-cooled condenser was also installed to condense NMP durmg reflux The system could routinely extract 1 to 2 kg of coal with 20 to 25 L of NMP. 

Figure 17-26. Cutaway drawing of a properly installed sealing fitting. [Courtesy of Crouse-Hinds Electrical Construction Materials, a division of Cooper Industries, Inc.)...

Cable termination fittings are available which also are approved as sealing fittings, and often incorporate a union in their design. Particularly for space-limited installations, the difference in length requirements for such dual-purpose devices, as compared to standard sealing fitting/cable terminator/union combinations, can be consequential. 

Accessibility. Sealing fittings should not be installed behind walls or in other inaccessible locations. 

For installations which might be very sensitive to accumulations of oil, a two-stage oil separator can be fitted. The second stage cools the gas to just above condensing temperature, and up to 99.7% of the entrained oil can be removed. Even so, a small quantity will be carried over. Sliding vane and screw compressors mayhave extra oil injected into the casing to assist with sealing, and this must be separated out and re-cooled. 

Column. The capillary column must be correctly installed into the inlet, a procedure that is inlet and instrument dependant. In general, the column end is placed a specified distance into the inlet, beyond a fitting at the bottom end of the inlet. Each instrument vendor provides specific instructions on column installation that should be followed carefully. It is especially important to ensure that the seal between the inlet and column is leak-free and not contaminated. 

Steel forged fittings with screwed ends may be installed without pipe dope in the threads and seal-welded (Fig. 10-133) to secure bubble-tight joints. 

LEAKAGE AND WEEP HOLES. To ensure a minimum of liquid leakage from one tray to another, bubble-cap risers should be fitted firmly or sealed into the trays, and an effective seal is necessary around the tray supports. In large columns, the trays are often made in sections for ease of installation. Each of these sections must be installed carefully to minimize leakage. 

FIGURE 8 A modular wall system has been installed in a manner that provides a smooth surface for cleaning. The fit of the components and the method of sealing are important when a modular wall is selected. (Courtesy of Portafab.)... 

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