COLUMN PIPE

The column pipe is of flanged construction and fabricated with carbon steel plate. The pipe columns are welded by automatic submerged arc welding processes. The plate thickness is 8mm for models 050 through 063, 10mm for models 071 through 125 and 12 mm for larger models. The pipe column flanges are machined between centers to ensure perfect alignment of the pump.

SUCTION BELL

The suction bell is of carbon steel or stainless steel plate construction.  It is machined to ensure shaft alignment and designed for a gradual reduction in cross sectional area to avoid sharp directional changes in the flow pattern and thus, minimizing losses due to flow separation at the pump entrance.

DISCHARGE ELBOW

It is of carbon steel plate fanged construction and completely machined to ensure proper alignment.

IMPELLER

The impeller is of welded construction using 316L stainless steel plate. Aerodynamic profile design using computerized fluid dynamics (CFD) and the surface finish provided by the laminated steel plate ensure higher efficiency than conventional casting methods. The impellers are structurally designed using finite element methods (FEM) to withstand loads way above normal operation as well as the collision loads due to accidental entry of solid bodies. All impellers are dynamically balanced before installation.

DIFFUSER

Is of carbon steel or stainless steel plate construction. Diffuser guide vanes are stamped with diffusion angles that permit maximum conversion of kinetic energy into pressure energy.  The cross sectional area is gradually enlarged to reduce losses due to flow separation. The diffuser is completely machined to ensure proper alignment with the column pipe and wear ring.

WEAR RING

Fabricated with AISI 316L stainless steel plate. It is completely machined to allow a small clearance with the impeller and thus, achieving high volumetric efficiency.  Electrical insulating rings prevent galvanic corrosion between the stainless steel wear ring and the carbon steel components.  Wear ring thickness is 8 mm for models 050 through 071, 10 mm for models 080 through 125 and 12 mm for larger models to ensure long service life and structural stability. For operation in less corrosive environments, the wear ring can also be of carbon steel construction.

SHAFTS

For ease of maintenance, the shaft is divided into three sections: line shaft, head shaft, and bowl shaft.  In water lubricated shafts (open line shaft), the line shaft is of turned, ground, and polished 316 stainless steel construction.  In oil lubricated shafts (enclosed line shafts), the line shaft is of turned, ground and polished 1045 carbon steel construction. In all models the head shaft is of 1045 carbon steel construction and the bowl shaft is of 316 stainless steel construction. 

HEAD SHAFT COUPLING

DELTA’s water lubricated shaft pumps incorporate a unique upper shaft coupling design. To avoid galvanic corrosion of the column, diffuser, and suction bell due to the presence of stainless steel shaft and impeller, the upper shaft coupling is constructed with electrical insulation.  This coupling electrically separates the impeller and shaft from the rest of the pump thus avoiding galvanic corrosion.

BEARING BOX

For belt drive applications the pump is supplied with a unique hollow shaft bearing system.  Bearings are oversized to assure a minimum life of 30.000 hours of operation.  An integral oil pump assures positive bearing lubrication.

LINE SHAFT CENTRAL SUPPORTS

Central supports are of carbon steel construction and entirely machined to ensure perfect alignment of the shaft.

BOLTS

All bolts are stainless steel 316 stainless steel and are electrically insulated to avoid galvanic corrosion.

PROTECTIVE COATINGS

Standard finish for DELTA pumps consists of one primer and an overcoat of COAL-TAR type epoxy paint applied over a near white SSPC-SP10 grit blasted surface.  The minimum coating thickness is 0.25mm (10 mills).  The inside surfaces of the suction bell and diffuser are coated with an additional overcoat of abrasion resistant epoxy paint.