The GBY Type is a serie of centrifugal pumps specifically
engineered to handle sulphuric acid (H₂SO₄), particularly at high
concentrations and often at elevated temperatures. They are a
staple in the chemical processing, non-ferrous metallurgy (e.g.,
copper, zinc smelting), and fertilizer industries where sulphuric
acid is a key process fluid.
1. Material of Construction (The Most Critical Aspect):
Pump Casing and Impeller: The standard and most common material is
Cast Iron (e.g., HT200).
Why? Concentrated sulphuric acid (93-98%) reacts with cast iron to
form a protective sulphate layer (FeSO₄) on the surface. This layer
passivates the metal, drastically slowing further corrosion. This
makes cast iron an economical and highly effective choice for
concentrated acid service.
Stainless Steel (e.g., 304, 316): Generally poor resistance to
sulphuric acid across many concentrations and is usually avoided
unless for very specific, mild conditions.
Alloy 20 (Carpenter 20): A premium nickel-chromium-molybdenum
stainless alloy with excellent resistance to sulphuric acid across
a wide range of concentrations and temperatures.
High-Silicon Cast Iron (e.g., Duriron): Offers outstanding
corrosion resistance but is very brittle.
Duplex Stainless Steels: For certain intermediate concentrations.
Applications
GBY pumps are used wherever concentrated sulphuric acid needs to be
transferred.
Acid Plants: Transferring product acid.
Metal Smelting: In electrolytic refining processes (e.g., copper
cathode production).
Fertilizer Production: (e.g., phosphate fertilizers).
Chemical Synthesis: As a reactant or catalyst in various chemical
processes.
Waste Acid Handling: In recycling and recovery systems.
Advantages of GBY Type Pumps
Specialized Design: Engineered from the ground up for sulphuric
acid, not just a generic pump.
Cost-Effective: The use of cast iron for concentrated acid service
offers a great balance of performance and cost.
Reliable: Robust construction and appropriate seal choices lead to
high operational availability.
Easy Maintenance: The back pull-out design drastically reduces
downtime for repairs.
Safety: Proper material and seal selection minimize the risk of
dangerous leaks.
Considerations
Material Sensitivity: Using a cast iron GBY pump for dilute acid
would lead to rapid failure. The fluid concentration and
temperature must be precisely matched to the pump's material grade.
Abrasion: If the acid contains suspended solids (e.g., in a dirty
process stream), standard cast iron may wear quickly. A hardened
material or a different pump type might be needed.
Not a Universal Pump: It is highly specialized. It should not be
used for other highly corrosive chemicals (e.g., hydrochloric acid,
chlorine bleach) without thorough review, as material compatibility
would be completely different.
