Welch Pumps

What are Welch vacuum pumps?

Across International is an American laboratory vacuum pump brand offering oil-free diaphragm and corrosion-resistant pumps for routine laboratory vacuum applications. Its specialized series is the flagship line, designed for chemical resistance and reliable performance in standard lab workflows.

What you will find:

• Corrosion-resistant, two-stage belt-driven systems specifically engineered to handle aggressive chemical vapors and highly corrosive gases.
• Heavy-duty vacuum systems equipped with explosion-proof motors to ensure safe operation in hazardous environments containing flammable vapors.
• Fully chemical-resistant, four-head diaphragm configurations designed to provide high-flow, oil-free vacuum performance for harsh solvent evaporations.
• Rugged, dual-stage oil-sealed pumps utilizing a reliable belt-drive mechanism to deliver deep, stable high-vacuum levels.
• Original equipment service kits packed with essential replacement parts to maintain optimum sealing and extend diaphragm operational life.
• Air-cooled diffusion systems engineered to boost vacuum throughput and achieve ultra-high vacuum ranges for specialized industrial or physics applications.
• Two-head, oil-free chemical duty pumps utilizing advanced dry technology to ensure clean, low-maintenance laboratory vacuums.

How to choose a Welch vacuum pump

Choose the Dryfast ULTRA series for oil-free chemical vacuum

The Dryfast ULTRA series provides PTFE-wetted, oil-free vacuum pumps suitable for routine chemistry and biology applications. Single-stage models are used for filtration, while two-stage models support deeper vacuum for rotary evaporation and concentration.

Choose the CRV Pro series for aggressive chemical resistance

The CRV Pro series is designed for highly corrosive environments, including strong acids and halogenated solvents, offering enhanced material resistance compared with standard diaphragm pump construction.

Confirm ultimate vacuum requirements

Single-stage Welch pumps typically reach ~50–100 mbar for filtration, while two-stage models achieve ~3–7 mbar for rotary evaporation and SpeedVac applications. Model selection should match the required vacuum level.

Consider control requirements

Most Welch pumps are used as standalone systems, but they can also be paired with external vacuum controllers for set-point regulation when more precise control is required.

Check noise and installation requirements

Noise levels vary by model, so specifications should be reviewed for bench placement or enclosed operation. Exhaust routing and ventilation should also be considered during setup.

Specifications context

Welch Dryfast pumps are designed for continuous operation with thermal protection that shuts down the motor under overheating conditions and restarts after cooling. They are widely used in North American laboratories due to their balance of cost, reliability, and chemical resistance.

As of 2026, Welch Dryfast ULTRA pumps remain a standard choice for oil-free diaphragm vacuum applications in research and analytical labs.

The MBP team is here to help—reach out today for a personalized quote.