SPECIAL SUPPORTING CASES:
Few special supporting cases near pumps, tall vessels and exchangers are described as follows:
Case – 1:
To avoid loading of suction nozzle due to control valve weight, which is nearby, if we provide a trunnion (non insulated as per normal practice) to take weight of control valve, then during operation such nozzle will move up and lift the trunnion off its base. This will load the nozzle and purpose of trunnion will not get served.
This can be avoided by insulating trunnion, so that it will remain hot and will expand upwards and will provide resting. Thus in most cases, the nozzle loading can be controlled without use of spring supports, near pump nozzles.
Case – 2:
When supporting a line coming from top nozzle of a short vessel as shown in FIG-22, if the temperature and material of the vessel and pipe line is same, then the line may be supported at ground level.
Case – 3
When supporting a line coming from a tall vessel and the line temperature is different from vessel, it should be supported from vessel at the neutral point with respect to vessel. Such point is normally near the nozzle itself (FIG-23). The pump should be connected through flexible loop connection to avoid nozzle loading.
Alternatively line may be supported at bottom (near pump) and loop may be provided at top as shown in
While supporting suction and discharge piping to a pump, the supports being provided should be sufficient to takecare the maintenance requirements of the pumps i.e. if the valves / strainers, on the pumps are taken out for maintenance, the lines should remain supported.
Exp. Suction line.
In comparatively larger size pipes when a resting support is required at location “A”, then an adjustable type supports should be provided. This is necessary due to the maintenance requirements – such as changing of gaskets, etc. (see FIG-27)