GH Multistage high pressure centrifugal pumps

Garbarino's multistage pumps family has been widely tested over the years in applications with pressures up to 40 bar. Now, with the newly developed GH pumps, we can achieve pressures to 85 bar and capacities to 500 m3/h.

APPLICATIONS

These pumps are mainly suitable for power generation and seawater desalination plants, for boiler feed water and reverse osmosis systems. Their usage can be extended to other fields such as snowmaking equipment, shipbuilding and offshore applications, pumping stations, pipeline test work.

CONSTRUCTION

The GH design is our latest innovation in multistage technology on the market, both the hydraulics and the mechanics have been developed to meet the increase demand for high pressure pumps. The GH family consists of 4 sizes (50-65-100-150) and 8 different hydraulics to grant a solution tailored to customers specifications. The pumps are horizontal multistage, radially split, the impellers are arranged between external bearings.
The main features are:

• feet cast with suction and delivery casings to grant stiffness and sturdiness
• UNI-DIN-ANSI-JIS-ISO standard flanges
• the suction flange can be set in three positions
• high efficiency close type impellers, low NPSHr suction impeller
• only one wear ring for each impeller, of the replaceable type
• oil-sealed external bearings with constant level oiler
• drum-type device for axial thrust balancing
• oversized shaft to minimize deflections

TECHNICAL FEATURES

• maximum capacity 500 m3/h
• maximum head 850 m
• maximum speed 3600 rpm, first critical speed above 5000 rpm
• single balanced mechanical seal
• thrust bearing air or water cooling (option)

GH pumps can be supplied in a wide range of materials of construction. From the basic version which casing is made of nodular cast iron (GS500 grade) and impellers in cast iron (G25 grade) moving to special alloyed steels such as AISI 316L, Duplex, Superduplex, Hastelloy B and C, Monel, Alloy 20. Fully bronze constructed pumps are also available.

KEY FACTORS

Special design of the first stage impeller in order to reduce NPSH required No balancing holes on the impellers therefore no recirculation between high/low pressure chambers, reduced losses, high efficiency.
One wear ring for each stage ONLY instead of two as per standard multistage (G pumps) therefore reduced possibilities of seizure.
Patented balancing device in order to reduce the recirculation flow from balancing drum to suction.
Use of special anti-galling material for wear rings.
Special hardening treatment for some rotating parts.
High flexibility thanks to the possibility of rotating the suction flange as desired