Installing The Mechanical Seal; Installing The Tension Plate - Xylem Bell & Gossett VTP Serie Manual De Instrucciones

Do not over tighten packing or excessive
CAUTION
wear can occur on the shaft or sleeve.

INSTALLING THE MECHANICAL SEAL

Vertical turbine pumps are usually supplied with cartridge
type mechanical seals, shipped assembled - ready
for installation, when mechanical seals are supplied.
Instructions for installing mechanical seals are provided
by the seal manufacturer. Consult the seal manufacturer's
instructions (furnished with the seal) for information
on the type of seal used. Additionally, refer to factory
furnished outline drawing and seal piping schematic on
complex seal piping arrangements.
GENERAL REQUIREMENTS FOR INSTALL SEALS
1. Check surfaces at the face of the seal housing and
at the bottom of the seal housing to insure that they
are clean, flat and free of burrs. The face surface
must be smooth to form a good sealing surface for a
gasket or O-ring.
2. Check that shaft is smooth, and free of burrs, nicks
and sharp corners that could nick or cut the O-ring
or shaft packing. When further clean up is required,
protect by covering the inside of the pump seal
housing. Remove burrs, nicks and sharp corners by
using a strip of emery cloth "shoeshine fashion" over
the shaft threads. File threads around the keyway
with a smooth mill file or emery cloth. Sharp edges
must be rounded.
3. Remove all chips and dust from the shaft area.
4. Check that all rotary unit parts of the seal fit over
the shaft. A pre-check may be made by removing the
O-ring(s) from the cartridge sleeve Inside Diameter
(ID) and then installing the seal on the shaft. Further
shaft clean up will be necessary when the seal will
not pass all the way into the seal housing.
5. Remove the seal after the pre-check and re-install
the sleeve O-ring(s).
6. Sparingly lubricate the shaft and sleeve ID with
the lubricant included with the mechanical seal or
recommended by the mechanical seal manufacturer.
The following lubricants may be used, for
water service, when no lubricant is supplied or
recommended by the mechanical seal manufacturer.
• Light oil (SAE #10 or 20)
• Dow Corning #4 Grease
• Silicone lubricant
• Wax or Clay
• Soapy water
Oil based lubricants will damage EPR / EPDM
elastomer O-rings. Silicone lube and soapy water are
safe for EPR / EPDM elastomer O-rings.
7. Install the O-ring or gasket, between the seal
housing and seal. Install the seal over the shaft and
ease it into position against the face of the seal box.
Take care when passing the sleeve and O-ring over
keyways or threads to avoid damaging the O-ring.
16
Do not bump carbon members against the
CAUTION
shaft as they may chip, crack or break.
8. Position seal gland on discharge head seal housing
and secure with capscrews (or nuts for studs)
provided. Tighten capscrews gradually and
uniformly in a criss-cross pattern, taking 2 or 3
passes.
Do not over tighten capscrews on gland.
CAUTION
This can distort seal seat and cause seal
failure.
9. Install all seal piping as required. Prior to making
final connections of sealing liquid pressurizing
lines, make sure the seal housing and all sealing
liquid lines are flushed free of dirt, scale and other
particles that would be abrasive to the sealing faces.
10. The Driver and Coupling must now be installed
per instruction. (See page 24 - INSTALLING
THE HOLLOW SHAFT DRIVER or page 26 -
INSTALLING THE SOLID SHAFT DRIVER).
INSTALLING THE TENSION PLATE WITH CAST IRON
TENSION NUT
INSTALLING THE TUBE TENSION PLATE
1. (See Figure 10). Lubricate tube threads and
underside of tension plate flange with thread
compound. Thread the tension plate (625) onto
the enclosing tube nipple (629) manually until its
shoulder rests on the discharge head.
TENSIONING THE ENCLOSING TUBE
The enclosing tube sags from its own weight as it is
installed and must be pulled tight (tensioned) to make
it straight. This section describes two methods of
tensioning the tube. The direct pull method is more
precise and is preferred. The second method--the
wrenching method--is given as an alternate.
NOTE: The correct tension is equal to the weight of the
enclosing tube plus 10%.
Weights per unit length for each tube size are given in the
Table 1. Multiply by total length of the tube to determine
the total weight.
TABLE 1 – Weight-per-foot of Enclosing Tubing
TUBE SIZE (INCH)
1¼
1½
2
2½
3
3½
4
5
6
DIRECT PULL METHOD
1. The upper end of the tube may be pulled by the
hoist to obtain the predetermined tension value.
WEIGHT PER FOOT (LB.)
2.99
3.63
5.02
7.66
10.25
12.50
14.98
20.78
28.57