Description
Welch 1399 DuoSeal Belt Drive Vacuum Pump 1/3 HP 115/230V 1725 RPM
The Welch 1399 is a belt-driven rotary vane vacuum pump designed for laboratory and industrial evacuation applications. The belt drive design enables flexible speed adjustment and produces quieter operation compared to direct-drive units. This unit features a 1/3 HP capacitor-start single-phase AC motor with dual-voltage capability, making it suitable for a wide range of lab and manufacturing environments requiring reliable vacuum generation for system evacuation, degassing, and evacuation of closed systems.
Specifications & What's Included
- Pump Model: Welch 1399 DuoSeal rotary vane vacuum pump
- Motor: Dayton 4K929 1/3 HP, single-phase AC capacitor-start motor
- Speed: 1725 RPM, 60 Hz
- Voltage: 115/230V AC (currently wired for 115V operation, can be rewired for 230V)
- Current Draw: 6.8A at 115V / 3.4A at 230V
- Motor Frame Size: 48
- Insulation Class: Class A
- Drive Type: Belt drive with pulley system
- Manufacturer: Sargent-Welch Scientific Co., Skokie, Illinois
- Country of Origin: United States
- Form Factor: Benchtop mounted unit with base
- Oil: Drained and not included with purchase
Applications
The Welch 1399 series vacuum pump is a workhorse in scientific and industrial settings, commonly found in research laboratories, quality control departments, and manufacturing facilities. These pumps are essential for evacuating closed systems, degassing liquids and gases, and providing general vacuum applications in experimental and production environments. The belt drive design is particularly valued in lab settings where speed adjustment flexibility and lower noise operation are beneficial. Built during an era of robust, maintainable American scientific equipment manufacturing, the 1399 remains a capable pump for legacy system support and ongoing laboratory operations. The dual-voltage capability makes it adaptable to different facility electrical standards, and the proven rotary vane design is well-understood and serviceable by experienced technicians.
This Welch 1399 DuoSeal belt-drive vacuum pump has been tested and is in good working order. It powers on reliably and produces a vacuum as expected. The unit is currently wired for 115 VAC operation but can be rewired for 230V use if needed. The oil has been drained and is not included with the purchase. As with any used vacuum pump of this age, it may benefit from routine servicing such as seal replacement and oil refresh to maintain peak performance. The unit shows general cosmetic wear consistent with laboratory use, including light paint scuffs and surface marks on the base and housing. Please view our photo set and contact us if you have any questions.
Warranty Information
Additional Information
Brand: |
Welch |
Model: |
1399 |
MPN: |
1399 |
Type: |
Belt Drive Rotary Vane Vacuum Pump |
SKU: |
47981 |
Motor Brand: |
Dayton |
Motor Model: |
4K929 |
Motor Type: |
Capacitor Start A.C. Motor |
Horsepower: |
1/3 HP |
Voltage: |
115/230V AC |
Current Rating: |
6.8A (115V) / 3.4A (230V) |
Speed: |
1725 RPM |
Frequency: |
60 Hz |
Phase: |
Single Phase |
Motor Frame: |
48 |
Insulation Class: |
Class A |
Drive Type: |
Belt Drive |
Current Wiring: |
115 VAC |
Pump Series: |
DuoSeal |
Manufacturer: |
Sargent-Welch Scientific Co. |
Seller Notes: |
Oil drained and not included. Wired for 115V, can be rewired for 230V. |
Country/Region of Manufacture: |
United States |
Form Factor: |
Benchtop |
Application: |
Laboratory, Scientific, Industrial Vacuum |
Review Status: |
Auto-Approved (needs review) 2026-07-04 |
Condition Notes: |
Welch 1399 DuoSeal vacuum pump tested and in working order—powers on and produces vacuum. Currently wired for 115V; can be rewired for 230V. Oil drained, not included. Shows typical lab wear; may need servicing to reach factory specs. |
