Flowserve BP - Manual (Page 11)

BP USER INSTRUCTIONS ENGLISH 85392725 10-09 (E)
Page 11 of 44 flowserve.com
3 DESCRIPTION
3.1 Configurations
The BP type barrel pump is a process pump that is
operated under high pressure/high temperature
processing conditions. The casing consists of an
outer casing (casing barrel) and an inner casing
(diffusers). As the suction and discharge nozzle are
made of forged carbon steel and integral with the
casing by welding, the pump is able to be dismantled
and reassembled without disturbing suction and
discharge piping.
3.2 Name nomenclature
The pump size will be engraved on the nameplate
typically as below:
6BP-1411S
 “6” = Nominal discharge size in inches
 “BP” = Pump Designation
 ”14” = Nominal Impeller size in inches
 “11” = Number of Stages, 4-14
 “S” = Special Impeller Design
3.2.1 Discharge
sizes
2, 3, 4, 6, and 8 Inches
3.2.2 Pump
Designations
BP= Single Suction Impeller
BPD= Double Suction Impeller
3.2.3 Impeller
sizes
8, 9, 10, 11, 12, 14, and 18 Inches
3.3 Design of major parts
Refer to Section 8 for sectional drawings.
3.3.1 Outer Casing(Casing Barrel)
A carbon controlled forged steel is used for the outer
casing. The outer casing is supported at the
horizontal centreline of the pump to minimize
coupling misalignment. The barrel is designed as a
whole to reduce any stress concentration by applying
FEM analysis for the optimum design.
3.3.2 Inner Casing(Diffuser, Inner Element)
Inner casing consists of stage pieces (1460.1-3) and
diffusers (1411, 1412, 1413). The inner casing is
designed for easy disassembling and assembling
since the diffusers and stage pieces are in one
integrated configuration. Each diffuser is mounted
with a shrink fit and a dowel pin to prevent the
rotation of the diffuser. The entire inner
element(diffuser) is pushed and secured axially
against the shoulder of the casing barrel with a
circular element spring(4260) located between last
stage piece and discharge head due to high
discharge pressure generated during pump
operation. The entire inner element is also prevented
from rotating by a dowel pin located between last
stage diffuser and discharge head. The inner
assembly expands and contracts freely due to
temperature variations without introducing thermal
stress in any of the pump parts. Self-flushing liquid for
mechanical seals is extracted from liquid in the first
stage piece through the flow passage drilled in the
first stage and the casing barrel.
3.3.3 Impellers and Wearing rings
Impellers are of the single suction closed type. They
are dynamically balanced individually and keyed to
the shaft. They are also secured on the shaft in
position with a spilt ring and a Spirolox ring, if
required. The first stage impeller is usually designed
with a lager inlet to reduce N.P.S.H requirements.
The diffuser rings are made of hardened chrome
steel. Each ring is pressed into its diffuser. If required,
replaceable impeller wearing rings can be furnished.
3.3.4 Shaft
The shaft is grooved to accommodate the split rings,
spirolox rings, if required, and a thrust ring for
positioning impellers and balancing drum.
3.3.5 Balancing
Drum
The pump is hydraulically balanced by a balancing
drum and balancing ring. The balancing drum is
secured against axial movement by a thrust ring and
against rotational movement by keys.
3.3.6 Discharge
Head
The discharge head is subjected to the full discharge
pressure of the pump. It is made of a forged carbon
steel using a Spiral Wound GASKET as the high
pressure seal. The discharge head contains the
balancing ring and supports the outboard stuffing box
and thrust end bearing housing.
3.3.7 Stuffing Box and Suction Head
Outboard stuffing box and inboard suction head are
fixed to the discharge head and the casing barrel
respectively with casing studs and nuts. Both of them
have cooling water chambers or steam jackets and
are supplied with the mechanical seals suitable for
the conditions of service. For details about the
installed mechanical seals, refer to manufacturer’s
instructions at the appendix.