Form V453 - 6 - Rev 2, ECN 4735 10/16/20
DESCRIPTION OF VAUGHAN
WET-WELL SCREW PUMP
The Vaughan vertical wet-well screw pump
is specifically designed for pumping whole
solids. The pump is supplied with a deck
plate to mount the pump, automatic oil level
monitor (for pump shutdown in case of seal
failure), and a discharge flange above the
deck plate with a pressure gauge tap.
A. DESCRIPTION OF MAJOR
COMPONENTS
Note: Please use the wet-well screw pump
exploded assembly parts list as an aid in
understanding this section.
SCREW-CENTRIFUGAL IMPELLER:
The
impeller on the Vaughan Triton pump
induces flow by propelling liquid material
through the pump inlet cone and into the
casing. The pumping action is a combination
of positive displacement and centrifugal
action. The OD of the impeller must be
positioned to closely clear the ID of the inlet
cone at the pump suction to achieve good
pumping efficiency. The standard impeller is
made of cast iron. Chrome-iron, 316SS, and
CD-4MCu materials are also available.
SUCTION CONE
: The inlet cone serves the
functio
n of a “wear plate”, sealing in the
pressure at the intake of the pump. The
pressure generated by the impeller is kept
inside the pump by the close clearances
between this suction cone and the impeller.
The inlet cone includes a cast-in spiral
groove to channel fiber out of the cone and
into the pump casing. This spiral groove
stops binding from overloading the drive
motor. The standard inlet suction cone is
made of ductile cast iron. Other available
materials are chrome iron, 316SS, and CD-
4MCu.
UPPER CUTTER:
The upper cutter ring (it is
screwed into the pump casing with LH
threads) uses two cutting dogs to cut against
cast-in teeth located on the rotating impeller
hub. The upper cutter is only a feature on,
4X6A, 6X6A, 8X8B, 10X10C, and 12X12C
Triton screw pumps.
BACK CUTTER:
Pumps that do not have an
Upper Cutter have a Back Cutter. The Back
Cutter system consists of two opposing
hardened steel insert cutters. One of the
insert cutters is stationary and located on the
back plate of the pump, while the other insert
cutter is located in the rotating impeller hub.
This feature is designed to minimize ragging
between the impeller hub and back plate.
MECHANICAL SEAL DESIGN
: Standard
Vaughan wet-well pumps use a high-quality
Vaughan-designed
cartridge
mechanical
seal to isolate and protect the oil-bath ball
bearing system from contamination from the
pumpage. The seal is located immediately
above the pump impeller on the pump shaft.
Mechanical seal faces are made of solid
silicon carbide for long life in abrasives. The
best indication of any problems with the
mechanical seal system is either a loss of oil
from the pump stem (or column) or, in
unusual cases, overflowing of the oil
reservoir. The pump impeller pumpout vanes
are designed to pull oil out of the pump stem
if a seal failure occurs and as long as pump
discharge pressure is not too high. (If the
pump is operating near shutoff head, it's
possible to push material up into the
reservoir.)
