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Welch’s dry WOB-L® piston vacuum pumps solve a common lab and industrial pain point: achieving strong, oil-free vacuum performance without compromising speed, reliability, or maintenance intervals. These pumps are engineered for standard duty applications where clean operation, consistent vacuum levels, and long service life are non-negotiable.

What Makes These Pumps Stand Out

  • Oil-Free Operation

WOB-L piston technology eliminates the need for oil, reducing contamination risk and maintenance.

  • Wide Range of Models

17 models available, from 0.4 to 7.1 cfm free air displacement, reaching vacuum depths of 5 Torr.

  • Consistent Performance

Maintains strong pumping speeds even near ultimate vacuum pressure.

  • Built-In Safety

All models include 1PH motors with thermal overload protection; several are UL component certified.

  • Flexible Applications

Suitable for:

  • Cell culture media filtration and aspiration
  • DNA/RNA/plasmid extraction
  • Vacuum ovens and filtering
  • Vacuum bag forming
  • Sampling, pick-and-place, package integrity testing
  • Turbidity and rice porosity testing
  • Integrated Features

Options include vacuum controllers, gauges, catch-pots, fluid collection vessels, and tank-mounted systems.

Welch Standard Duty

Model Highlights

 

Model

Free Air Displacement (cfm)

Ultimate Vacuum (Torr)

Max Vacuum (in. Hg)

Motor Power (HP)

2511

0.39

219

21.3

1/30

2563

2.3

5

29.8

1/3

2585

7.1

5

29.8

1/3

8150 (Tank System)

7.1

60

27.6

3/4

Each model is optimized for specific use cases. For example, the 8150 includes a 10-gallon ASME receiver and supports automatic on/off operation at set vacuum levels.

FAQs

It’s a dry, oil-free oscillating piston design that minimizes friction and wear, extending pump life and reducing maintenance.