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The Best Welch Pumps for Freeze Dryers

What's needed in a freeze dryer pump?

There are two major types of freeze dryer pumps:

  • General purpose units designed for no or low corrosivity
  • Pumps engineered for substantial chemical resistance 

This article is a great starting point for finding the perfect pump for your freeze drying application.


Why Welch?

Welch is one of the top manufacturers of laboratory vacuum pumps. With over a century in the industry, Welch has designed pumps for every lab application.

For freeze drying, Welch has several models up to the task (whatever the chemical resistance required). To simplify the search, we've narrowed down the choices to two key product lines, both of which are cost-effective solutions to freeze drying.


The best Welch pumps for freeze drying


Summary table


Freeze dryer size Compatible general purpose model Compatible corrosion-resistant model
1 to 2.5 L (drum manifold) CRVpro 4 1402N-01
4.5 L (drum manifold) CRVpro 6 1402N-01
6 to 12 L (drum manifold) CRVpro 8 1402N-01
12 to 18 L (stoppering tray dryer) CRVpro 16 1376N-01


For general purpose freeze drying: Welch CRVpro

For a versatile, cost-effective vacuum pump for freeze drying, you can't do better than Welch's CRVpro series.

Built for stability, CRVpro direct-drive rotary vane pumps promise a long lifespan (assuming proper maintenance). The CRVpro was designed for enhanced airflow which keeps the unit running 10°C cooler than comparable pumps. This low temperature reduces the chemical activity within the pump, extending its lifespan and lowering oil consumption.

More reliability features include protective coating -- PTFE coating on the oil case, and oxide coating on the pumping module -- and a large oil capacity that helps dilute freeze drying vapors. When working with acetonitrile vapors, the CRVpro can be paired with a cold trap.

With 4 separate models compatible with freeze dryers ranging from 1 to 18 liters, the CRVpro series is popular in numerous laboratories for its cost-effective, reliable performance.


For corrosive vapor freeze drying: Welch ChemStar

When working with highly corrosive vapors, a highly-resistant pump is a must.

The Welch ChemStar series is engineered for ruggedness: they're the most resistant pumps in Welch's entire product line. All vital components of these belt-driven vacuum pumps are corrosion-resistant. Like the CRVpro series, the ChemStar line is engineered with a large oil reservoir (2.1 liters) to dilute harmful contaminants.

A unique feature of each ChemStar is its low rotation speed, which guarantees less wear and a longer operational life. The ChemStar includes Welch Gold Oil when purchased, a premium blend designed for maximum chemical resistance.


Getting help

If you'd like free, specialized support in choosing a vacuum pump for your freeze drying application, feel free to reach out to us. We're available at hello@growinglabs.com and 1-833-476-9420. We supply lab vacuum pump brands as diverse as Welch, Agilent, Vacuubrand, and ULVAC, and we've helped hundreds of laboratories procure the perfect equipment.