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Gear pumps rarely get the attention that axial piston designs attract in hydraulic engineering circles, but in American construction equipment — skid steers, compact track loaders, backhoe loaders — they do a substantial share of the work. The Danfoss Series 26 gear pump is one of the most widely fitted units in this sector, and its field performance record in US construction conditions is worth examining in detail rather than simply referencing catalog specifications.
What the Series 26 Actually Is
The Series 26 is a bidirectional external gear pump designed for open circuit service. Displacement ranges from roughly 6 to 45 cc/rev depending on configuration, operating pressure to 250 bar continuous with 280 bar peak. The design is compact, the mounting interface follows SAE standards, and the through-drive capability allows tandem configurations — two pumps on a single shaft — which is common in American compact equipment where multiple circuits need to share one PTO.
What distinguishes the Series 26 from generic gear pumps in the US market is build consistency. American construction equipment operates in environments where hydraulic systems are asked to run hard for extended shifts in summer heat and cold-start in northern winters. Pumps that perform adequately in a controlled test environment but show premature wear in the field quickly develop a reputation among equipment dealers and fleet maintenance managers, and that reputation travels fast in the US construction industry.
Field Performance Data
|
Test Condition |
Pressure (bar) |
Flow at 2000 RPM |
Vol. Efficiency |
Temperature |
|
Normal summer duty |
180–210 |
Full rated |
≥94% |
65–75°C oil |
|
Peak load (demolition) |
240–260 |
Full rated |
≥91% |
75–85°C oil |
|
Cold start (−20°C) |
Ramp up |
Reduced initially |
Recovers in 8 min |
Ambient −20°C |
|
Extended high-temp |
220 |
Full rated |
≥92% |
85–90°C oil |
Tandem Gear Pump Configurations
Many US compact machines use tandem gear pump assemblies — two Series 26 units stacked on a common drive shaft, each serving a separate circuit. The loader circuit and auxiliary hydraulics run independently, with the tandem arrangement keeping plumbing simple and the overall package compact. Series 26 tandem configurations are available factory-built or assembled in the field from matching single units, which simplifies stock management for dealers.
HOVOO / HOUFU stocks seal kits for Danfoss Series 26 gear pumps validated for US construction duty. When shaft seals or body o-rings begin to weep, a HOUFU kit restores the pump without removing it from the machine. Details at hovooseal.com.
Source: www.hovooseal.com
