Installation Procedures | Hydrastep Pressure Parts |
The water column is delivered along with the correct number of electrodes of the relevant pressure type (high or low) and complete with gaskets or ferrules and fixing nuts, where applicable. The electrodes should only be fitted to the column after all erection and electrical work is completed and the water column is ready to be commissioned.
Caution: It is essential that the electrodes are NOT fitted until the acid and steam purging of the boiler drum has been completed. However, if it is essential that the Hydrastep be used to gauge the water level during acid cleaning, a sacrificial set of electrodes must be used for this task with a new set of electrodes provided for installation before normal operation is started. Sacrificial electrodes should be
discarded.
The water column is provided with a lifting eye at its upper end to be used for support from the local site superstructure.
Before fitting the water column, the following points must be checked:
a)Ensure that access to work on this part of the plant is clear and that the Column isolating Valves have been fitted to the Steam and the Water connections on the Drum and are ready to have the water column welded to them. All steam isolation valves should be fitted with their spindles horizontal.
b)Check that items of hardware required for supporting the water column are available and that the suspension points on the superstructure have been installed.
c)Water columns are normally supplied with a lifting/support eye, but where this is not the case, alternative support must be provided.
d)The water column and associated pipework are secured to resist sympathetic vibrations from surrounding plant.
e)Ensure that the relevant installation diagrams, support services including that of an approved welder, and suitable welding plant are available.
Note: All joints in pipework must be welded, tested and inspected in accordance with the approved welding procedure documents. Ideally, this should be to ASME B & PVC Section IX Welding Qualifications, but Local Regulations may otherwise apply. To minimise errors due to temperature difference between the water in the boiler drum and the water in the Hydrastep column, the length of the pipework between the drum and the Hydrastep column should not exceed 2 metres. Paths should be as straight and direct as possible.
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