Horizontal vessels and drums are relatively large diameter cylindrical pressure vessels used for a variety of process functions. Their height above grade is usually determined by the NPSH requirements of the pumps in the liquid outlet line or the gravity flow requirements to other equipment. And they are supported by the use of saddles (see Figure 13-1).
The arrangement of connections on the vessel is dependent on process requirements, access to valves and instruments and general maintenance.
The use of platforms and ladders in elevated drums is essential and they should be positioned according to the priorities listed in the preceding paragraph. The pictures below show two horizontal pressure vessels, of note is that in Figure 13-2 the support saddles are higher than normal and on Figure 13-1 there is a manhole located on the shell. Note the davit to open the manhole.
- Horizontal drums are designed and manufactured to ASME Section VIII Boiler and Pressure Vessel code.
- They consist of a fabricated shell made from welded plates, and elliptical dished heads at both ends.
- Support is provided through the use of saddles, one end is fixed and the other is allowed to slide by using slotted holes in the saddle.
- A manhole is provided for access, either at one of the heads or usually on the top of the vessel shell.
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| Figure 13-1: Drum with side manhole | Figure 13-2: Drum with extended saddles |
