FIGURE 1: As it can be seen in the figure, thermal expansion in both the horizontal and vertical legs can be absorbed by using hinged expansion joints. Following points should be taken into consideration by locating expansion joints to such piping systems:
1. The distances L1 and L2 should be made the maximum possible,
2. The distance L3 should be made the minimum possible.
In order to keep offset and frictional forces affecting the expansion joints and anchors small, the hinges should be designed in the way to compensate the pressure thrust and weight of the pipe between the two expansion joints.
FIGURE 2: As depicted in the fi gure, hinged expansion joints can be located at a “Z”-formed piping system, in order to absorb big amounts of expansions. Following points should be taken into consideration by locating expansion joints to such piping systems:
1. The distance L1 should be made the maximum possible,
2. The distance L2 should be made the minimum possible.
Planer pipe guides are used providing the thermal expansion in the vertical pipe leg to be taken as natural fl exibility in the horizontal pipe run. The usage of hinges enables the compensation of pressure thrust and installation of intermediate anchors.
FIGURE 3: As it can be seen in the fi gure, an intermediate anchor is located at the “U” bend dividing the pipe system into two equal expanding pipe subsystems. The number of expansion joints in the long piping system can be reduced by installing four hinged expansion joints in the ”U” bend of the system. In this way the pressure drop in the system is kept to a minimum, and the number of pipe supports can be reduced.
FIGURE 4: As depicted in the fi gure, the most appropriate design for a “Z” offset is found to be the one with two gimbal expansion joints. The thermal expansion in the vertical pipe leg is compensated with the natural fl exibility in the horizontal pipe run. The installed gimbal expansion joints admit expansion in both of the planes, while absorbing the pressure thrust. Intermediate anchors are used to absorb the low offset forces, at the same time the planer pipe guides controls the direction of the vertical movement.
FIGURE 5: As it can be seen in the fi gure, in some piping systems the natural flexibility of the horizontal pipe leg is insuffi cient to absorb the thermal expansion in the vertical pipe leg. In these cases two gimbal expansion joints have to be used in conjunction with a hinged expansion joint. Following points should be taken into consideration by locating expansion joints to such piping systems:
1. The distances L1 and L2 should be made the maximum possible,
2. The distance L3 should be made the minimum possible.
A planer pipe guide should be used on the upper horizontal pipe leg, while a regular pipe guide is used on the lower horizontal pipe leg.
