Flowserve Guardian Sealless Metallic - Manual (Page 21)

GUARDIAN USER INSTRUCTIONS ENGLISH 71569212 08-11
Page 21 of 68 flowserve.com
Refer to section 3.4 for performance and operating
limits.
4.6.2.1
Guardian self-priming pumps
The suction piping must be as short as possible and be
as close to the diameter of the suction nozzle as is
practical. The pump works by removing the air
contained in the suction piping. Once removed, it
operates exactly the same as a flooded suction
standard pump. Longer and larger suction pipes have a
greater volume of air that has to be removed, resulting
in longer priming time. The suction piping and seal
chamber must be airtight to allow priming to occur.
When possible, it is recommended that suction piping
be sloped slightly towards the casing to ensure no fluid
is lost down the suction line during priming.
4.6.3
Discharge piping
Install a valve in the discharge line. This valve is
required for regulating flow and/or to isolate the pump
for inspection and maintenance.
When fluid velocity in the pipe is high,
for example, 3 m/s (10 ft/s) or higher, a rapidly
closing discharge valve can cause a damaging
pressure surge. A dampening arrangement should
be provided in the piping.
4.6.3.1
Guardian self-priming pumps
During the priming cycle, air from the suction piping is
evacuated into the discharge piping. There must be
a way for this air to vent. If air is not able to freely
vent out the discharge pipe, it is typically
recommended to install an air bleed line. The air
bleed line is typically connected from the discharge
pipe to the sump. Care must be taken to prevent air
from re-entering suction pipe.
4.6.4
Allowable nozzle loads
Flowserve chemical process pumps meet or exceed
the allowable nozzle loads given by ANSI/HI 9.6.2.
The following paragraphs describe how to calculate
the allowable loads for each pump type and how to
determine if the applied loads are acceptable. The
configuration covered is for ASME B73.3 pumps,
including the Guardian G & H series.
4.6.4.1
Guardian G & H series pumps (ASME
B73.3)
The following steps are based upon ANSI/HI 9.6.2.
All information necessary to complete the evaluation
is given below. For complete details please review
the standard.
a) Determine the appropriate casing “Material Group
No.” from figure 3-8.
b) Find the “Casing material correction factor” in
Figure 4-9 based upon the “Material Group No.”
and operating temperature. Interpolation may be
used to determine the correction factor for a
specific temperature.
c) Find the “Baseplate correction factor” in Figure
4-10. The correction factor depends upon how
the baseplate is to be installed.
d) Locate the pump model being evaluated in Figure
4-14 and multiply each load rating by the casing
correction factor. Record the “adjusted Figure 4-14
loads”.
e) Locate the pump model being evaluated in
Figures 4-15 and 4-16 and multiply each load
rating by the baseplate correction factor. Record
the adjusted Figure 4-15 and 4-16 loads.
f) Compare the “adjusted Figure 4-14 loads” to the
values shown in figure 4-13. The lower of these
two values should be used as the adjusted figure
4-13 values. (The HI standard also asks that figure
4-13 loads be reduced if figure 4-15 or 4-16 values
are lower. Flowserve does not follow this step.)
g) Calculate the applied loads at the casing flanges
according to the coordinate system found in
figure 4-11. The 12 forces and moments possible
are Fxs, Fys, Fzs, Mxs, Mys, Mzs, Fxd, Fyd, Fzd,
Mxd, Myd and Mzd. For example, Fxd
designates Force in the “x” direction on the
discharge flange. Mys designates the Moment
about the “y”-axis on the suction flange.
h) Figure 4-12 gives the acceptance criteria
equations. For long coupled pumps, equation
sets 1 through 5 must be satisfied. For close
coupled pumps, only equation sets 1 and 2 must
be satisfied.
i) Equation set 1. Each applied load is divided by
the corresponding adjusted figure 4-13 value.
The absolute value of each ratio must be less
than or equal to one.
j) Equation set 2. The summation of the absolute
values of each ratio must be less than or equal to
two. The ratios are the applied load divided by
the adjusted figure 4-14 values.
k) Equation sets 3 and 4. These equations are
checking for coupling misalignment due to nozzle
loading in each axis. Each applied load is divided
by the corresponding adjusted load from figure 4-15
and 4-16. The result of each equation must be
between one and negative one.
l) Equation set 5. This equation calculates the total
shaft movement from the results of equations 3
and 4. The result must be less than or equal to
one.