Flowserve SVCN 7, Installation Operation & Maintenance

SVCN 7 INSTALLATION, OPERATION, & MAINTENANCE 

1.4.2.1 Mechanical Seal 

There are many variations of the mechanical seal: typically, it is a precision device in which the face 
of a washer (or ring) that is retained to the shaft sleeve rotates against the face of a seat that is fixed to 
the seal end plate or the head. The sealing faces are highly polished. Loading is accomplished by a 
spring and hydraulic force pushing against the rotation washer. Some seals feature a rotating pumping 
ring, which speeds up the flow of liquid past the sealing faces, allowing the use of smaller heat 
exchangers for cooling the flushed liquid. To keep the mechanical seal at a nominal temperature, 
either pumpage or liquid from an external source is constantly circulated around the component parts 
while the pump is operating. Liquid from an external source flows into, and the heated (or flush) 
liquid flows out of, the seal chamber via flush piping. Dissipation of the heat in the flush liquid is 
sometimes accomplished by means of a heat exchanger, depending on the plant system.  

1.4.2.2 Packing 

A packing gland and packing box bushing retain the packing rings which are installed around the 
shaft sleeve. Even compression of the rings, staggered cuts, and a slight amount of packing leakage is 
required for satisfactory service; otherwise friction and heat will likely destroy the packing. 
Flowserve prefers to use a lantern ring with packing in order to circulate liquid from an external 
source around the packing, removing some of the packing-generated heat. The packing box bushing is 
usually pressed into the head from the outside but it may be designed for installation from the inside. 
In either event, it is tack welded or secured with set screws which are staked.  

1.4.3 BEARING LUBRICATION 

The automatic oiler on the side of the housing maintains the oil level below the lowest balls of the 
bearings. The basic system is supplemented by oiling rings that turn with the pump shaft, splashing 
oil on unsubmerged balls. The purge mist, if installed, is blown into the housing from the plant's 
system. When the bearings are lubricated by a pure mist, ring oil is not used; the bearings are 
lubricated solely by droplets of oil in the mist. 

1.5 RECEIPT INSPECTION 

Your pump was carefully checked at the factory prior to shipment to ensure compliance with the 
requirements of your order. It is suggested that the pump be inspected upon arrival. As a minimum, 
the following items should be checked: 

1.  Inspect the shipping containers for damage or moisture. The condition of the skid and covering is 

indicative as to the way the shipment was handled. Broken skids, torn coverings, bend hold-down 
bolts, broken straps, etc., indicate rough handling. 

2.  Remove the shipping enclosure and visually inspect all pump components for damage. 

3.  Inspect the preservative coating on various parts. If necessary, renew preservative in areas where 

it has been rubbed or scraped. 

4.  Inspect all painted surfaces. If necessary, touch up the areas where paint has been chipped or 

scraped. 

5.  Inspect all covers over pump openings and piping connections. If covers or seals for the covers 

are damaged or loose, they are to be removed, and a visual inspection made of the accessible 
interior areas for accumulation of foreign materials or water. If necessary, clean and preserve the 
interior parts as noted above to restore the parts to the as-shipped condition. Install or replace 
covers and fasten securely. 

DO2604-13 

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