ITT Goulds Pumps
3935 Low Flow - High Head Multi-Stage Pumps
The Goulds 3935 is a diffuser-type multistage pump purpose-built for low-flow, high-head services where efficiency is critical. It generates very high pressure from a compact barrel-type casing, making it a natural fit for boiler feed and high-pressure cleaning and descaling duties.
Product Benefits
- Rigid one-piece shaft: A single one-piece shaft with no internal coupling minimizes deflection, which protects the close internal clearances that multistage pumps depend on.
- Quiet, gentle hydraulics: The hydraulic design uses many small-diameter impellers running at low tip speeds, so the pump is notably quiet and gentle on its own wear parts, translating directly into lower maintenance costs.
- Adjustable staging: Impellers can be added or de-staged, so the pressure output can be adjusted to the duty without changing the pump.
- Low-NPSH first stage: The first stage is a low-NPSH mixed-flow impeller that achieves good suction performance without resorting to a cavitating inducer.
Where It's Used
- High-pressure water services: Typical services are boiler feed, process water, spraying systems, and high-pressure cleaning.
- RO and descaling: It also serves reverse osmosis and descaling duties.
- Low flow, high head: It is the pump to reach for when flows are modest but the required pressure is very high, a combination that defeats most single-stage designs.
Good to Know
- Hard-wearing materials: The barrel casing is carbon steel closed with a dry buttress thread, while impellers, diffusers, and heads are NI-Resist and the shaft is K-Monel, a corrosion- and wear-resistant combination for hot water duty.
- Standard seal: The standard mechanical seal is a single-spring design with stainless steel metal parts and Viton secondary seals.
- Connection options: Threaded connections are standard, with heavy-class flanged construction available as an option.
- Hotter services with cooling: Hotter services are possible when cooling is provided, so the cooling arrangement should be part of the selection conversation.
