Copyright Goodheart-Willcox Co., Inc. 196 Fluid Power Care must be taken when working with adapter fi ttings as several thread sizes and fl are angles exist. Attempting to mate different threads or fl are angles will cause problems. Attachment methods from the fi rst, second, or third categories are used with adapter fi ttings to con- nect major components. These components include pumps, valves, and actuators. Attachment methods from the fi rst, second, or fourth categories are used when connecting an adapter to hose and tube-end fi t- tings. In addition, adapters are available that form 45° or 90° elbows. Swivel fi ttings are also available to mini- mize hose twisting as a component moves or rotates during system operation. 8.2.4 Selecting Appropriate Conductors There is no question that fl uid conductors and their asso- ciated fi ttings are an essential part of any hydraulic sys- tem. Many factors must be carefully considered to obtain the most appropriate type and size of conductors and fi t- tings. However, selection is often not as carefully consid- ered as it should be. The result can be a system with con- ductors that cost more than necessary, contribute to inef- fi cient system operation, fail prematurely, or are diffi cult to disconnect when system service is required. Many of these problems can be reduced or eliminated by selecting conductors only after a careful analysis of system opera- tion, the environment in which the system operates, and manufacturer data sheets for conductors. 8.3 Analysis of Circuit and System Operation Selecting a conductor requires an examination of the hydraulic circuit involved. It also involves examining the total hydraulic system and the mechanisms oper- ated by the system. This complete analysis should not only take into consideration the obvious elements, such as system pressure and fl ow, but also include machine- related factors. Machine-related factors include such things as vibration and required machine member movement that directly affect conductor performance. The following factors need to be carefully considered when selecting and installing conductors of any type: • Pressure rating. • Flow characteristics. • Temperature. 8.3.1 Pressure Rating The recommended maximum operating pressure rat- ing of a conductor is usually readily available in catalog Pipe fitting, adapter fitting, or component casting Tapered pipe threads Category 1 O-ring Straight threads Category 4 Tubing Jam nut 37° or 45° flare Clamp bolts Split flange Flanged-end conductor Component body O-ring Category 3 Category 2 Goodheart-Willcox Publisher Figure 8-25. A variety of connection methods are used to attach fluid lines and components to provide sealing against fluid leaks while promoting easy assembly and disassembly.