DPV and DPHSI Low NPSH brochure

Summary

Product identification

The Duijvelaar Pumps (DP) low-NPSHr range includes DPV and DPH(S)I pump models. The low NPSHr option is available for DPV (C/S) and DPH(S)I 2, 4, 6, 10, and 15 models, in both 50 and 60 Hz versions.

Overview / Key Features

DP has developed a specially designed low NPSHr impeller and bottom stage casing to create a pump range with significantly lower NPSHr values, preventing cavitation and pump failure. This design allows for lower NPSHr overall and extends low NPSHr performance to higher flows where conventional pumps typically see a sharp increase in NPSHr.

Operating Limits / Applications

Cavitation is caused by low suction pressure in relation to the liquid's internal resistance and vapor pressure (which increases with temperature). The low NPSHr design allows these pumps to be used in a wider range of applications where low suction pressure and/or high vapor pressure would normally cause problems, including:

• Hot water (Boiler feed)
• Feed from a (low) reservoir
• Situations with little to no space between the deaerator tank and the pump
• Applications where no vented tanks are available

Mechanical / Hydraulic

The low NPSHr impeller design differs from standard impellers with:

• Larger inlet diameter
• Increased impeller opening height
• Reinforced impeller base plate
• Modified vane design
• Larger total height, compensated by an adjusted bottom casing.

Extended CFD calculation models have resulted in a design with lower fluid velocities at the core of the impeller. A pump equipped with a Low NPSHr impeller has the same height as the standard version and can be easily exchanged.

Electrical

Despite the low NPSHr impellers normally requiring slightly more power, there are no requirements for increased motor power due to efficient rimming of the low NPSHr components.

Performance Data

Performance curves are provided for specific models, such as DPV 10 B Low NPSHr and DPV 15 B Low NPSHr, operating at 2900 rpm with a liquid density of 1000.0 kg/m³. These curves illustrate Flow (m³/h, US.gpm, IM.gpm, l/s), Total Dynamic Head (TDH) (m, ft), and NPSH₃% (m, ft) for both standard and low NPSHr configurations. See the official PDF for exact tabulated values and detailed performance curves.

Disclaimer This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions from the original OEM PDF. Contractual data must always match the specific OEM PDF revision used for the project.

Official datasheet (PDF)

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