Apr. 13, 2017
Location – The double-pipe heat exchanger should be located in a clean, open area, with sufficient clearance at the head of the heat exchanger to remove the tube bundle. In the case of Fixed Tube Sheet units, allow room on both ends of the unit to remove the heads for inspection and tube cleaning. In the case of Floating Rear Tube Sheet units, allow sufficient space at the stationary head end to remove the tube bundle, and sufficient space at the floating head end to permit removal of the shell cover and/or floating head cover.
The foundation of the floating heat exchanger should be adequate so that the unit will not settle and cause piping strains. Foundation bolts should be set to allow for settling inaccuracies. In concrete footings, pipe sleeves at least one size larger than the bolt diameter slipped over the bolt and cast in place are best for this purpose, as they allow the bolt center to be adjusted after the foundation has set.
Foundation bolts should be loosened at one end of the unit to allow for free expansion and contraction of the heat exchanger shell. Slotted holes are provided for this purpose. Exchangers should be set level and square so that pipe connections can be made without forcing.
Fittings & Piping – Provide valves and bypasses in the piping system so that both the shell-side and the tube-side may be bypassed to permit isolation of the unit for inspection and repairs. Long radius elbows should be used in lieu of standard elbows wherever possible, because of their superior flow characteristics.
When not integral with the exchanger nozzles, thermometer well and pressure gauge connections should be provided in all piping to and from the unit, and located as close to the unit as possible. Vent valves should be provided so units can be purged to prevent vapor or gas binding. Special consideration must be given to discharge of hazardous or toxic fluids. Drain connections should not be piped to a common closed manifold.
In all installations, care should be taken to eliminate or minimize transmissions of fluid pulsations and mechanical vibrations of the heat exchanger. Quick-opening and closing valves controlling fluids to or from the heat exchanger may cause water or steam hammer, which can cause serious damage to the heat exchanger.
Cleanliness Provisions – All heat exchanger openings should be inspected for foreign material.
Protective plugs and covers should not be removed until just prior to installation. The entire system should be cleaned before starting operation. Under some conditions, the use of strainers in the piping may be required. Convenient means should be provided for cleaning the unit as suggested in the Maintenance section.