Product Information

This Direct Drive Pump (also known as a direct drive vacuum pump) is driven by an electric motor and is manufactured by Welch. These pumps can achieve a deep vacuum and are affordably priced relative to their extreme value. The pump’s motor spins at a constant speed based on the type of motor used. Unlike a belt driven vacuum pump, these motors are directly connected to the the driveshaft of the unit. In general, electric motors usually spin the pump at either 3450 RPM or 1725 RPM. The simplistic design of these pumps helps contribute to their reduced cost, and maintenance is somewhat simpler than on some other, more complicated models.

Maintenance should be carried out on the pump based on user manual guidelines, which will greatly contribute to the longevity of the pump. Some sample applications for direct drive pumps are: Vacuum Ovens, Freeze Dryers, Centrifugal Concentrators, and more. This direct drive pump is not meant for aspiration, filtration or other applications requiring operation above 30 torr. These Welch pumps can maintain a deep vacuum while remaining portable down to .1 micron, and they have an 11.3 CFM flow rate.

A direct drive pump is a crucial piece of equipment for any lab, and they are not cheap. That is why we recommend a cold trap when using this pump to prevent condensation of contaminants building up inside. Despite the cost, it is an enormously beneficial piece of equipment for many laboratories.

If you are having trouble selecting vacuum pumps, please feel free to call Lab Society and we will guide you through the process. Feel free to browse our catalog to get a sense of the benefits and drawbacks of different types of vacuum pump models, as there are many clear trade offs to consider when making the final decision for your own lab.

System Specifications

Model: 8925

Pump Stats

Power115v, 60 Hz, 1 phase,  N. American Plug
CFM (L/Min)11.3 (320)
Max vacuum Torr0.001
Motor horsepower (watts)3/4ths (560W)
Tubing (mm)9/16, 13/16 (14, 20)
Ultimate pressure  Torr (mbar)4 x 10^-4(0.00053)
Type of pumpLaboratory Vacuum
Exhaust Thread NPT1-20 thread
Intake thread NPTUNIBARB (1-1/8-20)
Gas Ballast Yes


Centrifugal concentratorsMedium to large size
Vacuum ovensMedium to large size
Freeze dryers Medium to large size


Weight (Kg)63 (31.3)
Shipping Weight (Kg)77 (34.6)
Unit dimensions (cm)22 x 7.1 x 11"(56.4 x 17.9 x 27.9)
Shipping dimensions (cm)29 x 10 x 14" (73.7 x 25.4 x 35.6)

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