Couplings coupling installation

Couplings must be installed properly if they are to operate satisfactorily. This section discusses shaft and coupling preparation, coupling installation, and alignment. 

A careful inspection of both shaft ends must be made to ensure that no burrs, nicks, or scratches are present that will damage the hubs. Potentially damaging conditions must be corrected before coupling installation. Emery cloth should be used to remove any burrs, scratches, or oxidation that may be present. A light film of oil should be applied to the shafts prior to installation. Keys and key-ways (discussed in Section 59.3) also should be checked for similar defects and to ensure that the keys fit properly. Properly sized key stock must be used with all keyways do not use bar stock or other material. 

Any defects, such as burrs, should be corrected before the coupling is installed. Defects on the mating parts of the coupling can cause interference between the bore and shaft, preventing proper operation of the coupling. 

The specific installation procedure is dependent on the type and mounting configuration of the coupling. However, common elements of all coupling installations include spacing, bolting, lubrication, and the use of matching parts. The sections to follow discuss these installation elements. 

However, these stringent new requirements created a need to accelerate the development of specifically targeted catalysts. Ashland decided to initiate its own catalyst preparation program, coupled with installation and development of advanced testing equipment, to speed the evolution of advanced catalysts. 

Straight Pipe Threads These are confined to light-weight couplings in sizes 2 in and smaller (Fig. 10-132). Manufacturers of threaded pipe ship it with such couplings installed on one end of each pipe. The joint obtained is inferior to that obtained with taper threads. The code limits the joint shown in Fig. 10-129 to 1.0 MPa (150 Ibftin ) gauge maximum, nontoxic fluids. 

Other phenyl-pyrrole and phenyl-pyridine analogues of rhazinilam, having seven to nine-membered B-rings, have been synthesized using a Suzuki-Miyaura biaryl coupling to install the biaryl bond, Fig. (37). 

Use of Junction Box.—Figure 14-illustrates a wiring diagram for a multiple-couple installation which is very useful in saving compensating lead wire and in... 

Couples Purposely Insufficiently Immersed-— It is frequently desirable purposely to immerse the couple to an insufficient depth. In many processes the furnace is operated at such a high temperature that a thermocouple or protecting tube cannot withstand the severe conditions to which it may be subjected. In this case the couple may be immersed only part way through the furnace wall, or to a distance flush with the inner wall of the furnace. The temperatures indicated by couples installed in this manner are always lower than those of the furnace interior, but they bear a fairly definite relation to the temperature of the furnace, and hence the method is satisfactory for temperature control and reproduction of furnace conditions from day to day. 

They found that combination of the Ir(T) catalyzed C-H borylation and Suzuki coupling sequence led to a two-step, one-pot C-H Suzuki arylation that enabled direct transformation of the N-Boc pyrrole to the C3 arylated intermediate in 78% yield. Following installation of the required acyl group, an application of their oxidative Pd-catalyzed C-H alkenylation reaction enabled formation of the key structural architecture of the natural deliver the natural product. The orthogonal selectivity characteristics displayed by these C-H functionalization processes makes possible iterative functionalization of the heteroaromatic pyrrole core. Utilization of the highly versatile C-H borylation - Suzuki coupling to install the aromatic functionality opens up possibilities of facile analogue synthesis via this route. 

Figure 13.1.11 compares the total HC emissions of various catalysts in the FTP-75 engine test cycle, after engine aging at 750°C for 100 h. The catalyst location is in so called close-coupled converter installed 400 mm downstream from the engine. 

A silyl enol ether was employed as the nucleophile in a synthesis of lycopladine A 6.211 (Scheme 6.93). ° Gold-catalysed cyclization onto an iodoalkyne 6.208 gave a vinyl iodide 6.209 then allowed a Suzuki coupling to install an a, 3-unsaturated imine. After coupling, the imine 6.210 underwent an electrocyclic ring closure to form the pyridine ring of the natural product. Another synthesis of this alkaloid is presented in Scheme 9.62. 

One of the most reliable methods for the construction of an oligoheteroarene structure is the transition-metal-catalyzed cross-coupling reaction [26]. However, a problem to be overcome remains in the cross-coupling. The installation of a metal group into heteroaromatic compounds is often dififlcult because of problems with the stability of the resulting heteroaromatic metal reagent [27]. For example, 2-pyridyl boronic acid and its esters are easily decomposed by proton [28]. In addition to this problem with stability, the transmetallation of an electron-deficient heteroaromatic boron reagent to palladium is relatively slow [29]. 

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