TCO-OFFSHORE-0015 - Void Space Preservation of Centrifugal Pumps

Internal components requiring protection (Power End)
• Bearing (Housing) casing
o Generally made of iron but can involve a wide variety of materials, from stainless steels to plastics.
o Oil lip seals or labyrinth ring seals.
• Rotating elements
o Shafts, bearing, mechanic seal components.
Internal components requiring protection (Process Side)
• Vault casing
o Generally made of Iron but can be a wide variety of materials, from stainless steels to plastics.
• Rotating elements
o Impeller, shaft, mechanical seal components.
External components requiring protection
• All non-coated or painted surfaces shall be protected with a brush or sprayed on VpCI product.
• Pump shaft should be preserved with a brush or sprayed on VpCI product
o Caution should be taken to minimize excess product on the oil seal.
o Shaft may also require additional protection to be installed, to prevent physical damage.
• Pump inlet and outlet nozzle flange faces shall be preserved and protected from physical damage.
• For long term storage outdoors, UV protection (shrink wrap) should be considered.

Internal inspection should be performed via removal of inspection panels or borescope. Most often, the only method of inspection is through the oil fill plug (Item # 53) via a 4 to 6mm articulating borescope. Objective is to visually inspect the condition of the housing (casing) internals, rotor or shaft, and bearings (Items # 42 A/B& 31) looking for signs of corrosion, water, discoloration, and physical damage.
Note: Determine the type of oiler on the pump; often there will be a constant level bowl-type oiler. These should be removed and casing hole plugged, as they are a source of moisture ingress and air exchange. If they cannot be removed, pumps should be wrapped and sealed in UV rated plastic.

These should be removed and casing hole plugged, as they are a source of moisture ingress and air exchange. If they cannot be removed, pumps should be wrapped and sealed in UV rated plastic.

Once inspection is complete, fill pump with pre-determined preservation fluid, such that the fluid is just below the pump shaft, but not at a height above the lowest point of the oil seals. Oil could leak from oil seal if fluid is at or above the pump shaft while pump is not in operation. Preservation fluids should be a mixture of light oil and a VpCI oil additive. Having a mixture of oil and VpCI will allow for the pump to be rotated while providing VpCI protection in the void space. After the correct level has been achieved, replace fill plug vent (Item # 53) with a non-vented plug to stop air exchange to the pump internals.

An internal inspection should be done on the process side of the pump through the suction or discharge nozzles or through the casing drain plug. Objective is to inspect the internal casing and impeller for corrosion, signs of physical damage, and moisture ingress. Apply pre-determined VpCI product. Product and product application should be determined by pump component materials, process compatibility, commissioning, and operational constraints.