Description
Welch Duo-Seal Belt-Drive Vacuum Pump Dayton 6K376D 3/4 HP 115/208-230V 1725 RPM
Oil-sealed rotary vacuum pump with belt-drive design. Operates on single-phase AC power and achieves vacuum levels suitable for laboratory and industrial applications requiring consistent pumping capacity.
Specifications & What's Included
- Motor: Dayton 6K376D, 3/4 HP, 1725 RPM, H56 frame
- Power: 115V or 208-230V AC, 60 Hz, single phase
- Drive: Belt-drive with 4L490 Demco belt
- Ultimate Vacuum: < 0.05 micron at 300 RPM
- Tested Vacuum: Approximately -28 in Hg
- Oil Type: Duo-Seal proprietary oil (required)
- Manufacturer: W.M. Welch Mfg Co, Chicago, IL
Applications
Belt-drive oil-sealed pumps are used in laboratory settings, industrial processes, and HVAC applications requiring moderate vacuum levels. These vintage Welch units are found in research labs, degassing operations, and equipment maintenance. Compatible with systems requiring 115V or 208-230V single-phase power.
Condition: Used
This Welch Duo-Seal belt-drive vacuum pump has been tested and confirmed working at our facility, pulling approximately -28 in Hg on our in-house gauge. The pump and Dayton 6K376D motor are mounted on a steel base frame and show the kind of wear you'd expect from a vintage industrial piece — paint loss and grime on the pump body, surface rust on the motor pulley and flywheel, and general patina throughout. The drive belt (4L490) is intact. The unit ships via freight with the oil drained and removed; the buyer will need to add the correct Duo-Seal oil before running the pump. Please view our photo set and contact us if you have any questions.
This Welch Duo-Seal belt-drive vacuum pump has been tested and confirmed working at our facility, pulling approximately -28 in Hg on our in-house gauge. The pump and Dayton 6K376D motor are mounted on a steel base frame and show the kind of wear you'd expect from a vintage industrial piece — paint loss and grime on the pump body, surface rust on the motor pulley and flywheel, and general patina throughout. The drive belt (4L490) is intact. The unit ships via freight with the oil drained and removed; the buyer will need to add the correct Duo-Seal oil before running the pump. Please view our photo set and contact us if you have any questions.
Warranty Information
We stand behind every item we sell with a 30-day money-back guarantee. If your item arrives not as described, you may return it within 30 days for a full refund. Please inspect your purchase upon arrival and contact us with any questions.
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Additional Information
Brand: |
Welch |
Model: |
Duo-Seal |
MPN: |
Duo-Seal |
Type: |
Belt-Drive Oil-Sealed Rotary Vacuum Pump |
SKU: |
46991 |
Motor Brand: |
Dayton |
Motor Model: |
6K376D |
Motor Power: |
3/4 HP |
Motor Voltage: |
115V / 208-230V AC |
Motor Current: |
10.8A (115V) / 5.3-5.4A (208-230V) |
Motor Speed: |
1725 RPM |
Motor Phase: |
Single Phase |
Motor Frequency: |
60 Hz |
Motor Frame: |
H56 |
Drive Type: |
Belt Drive |
Drive Belt: |
4L490 Demco (Dayton Electric Mfg Co) |
Ultimate Vacuum: |
< 0.05 micron at 300 RPM |
Vacuum Achieved (Tested): |
Approx. -28 in Hg (measured at our facility) |
Oil Type: |
Duo-Seal oil (proprietary — use only Duo-Seal oil) |
Pump Design: |
Oil-sealed rotary, vintage belt-drive |
Manufacturer Location: |
W.M. Welch Mfg Co, Chicago, IL, USA |
Country/Region of Manufacture: |
United States |
Power Requirements: |
115V or 208-230V AC, 60 Hz, Single Phase |
Form Factor: |
Benchtop / Base-Mounted |
Shipping Method: |
Freight — oil drained prior to shipment |
Seller Notes: |
Tested working; ships freight with oil drained. Buyer must add Duo-Seal oil before use. |
Condition: |
Used – Inspected and Tested |
Review Status: |
Auto-Approved (needs review) 2026-07-04 |
Condition Notes: |
This Welch Duo-Seal belt-drive vacuum pump was tested working at our facility, pulling ~-28 in Hg. Shows age-related wear and paint loss. Ships freight with oil drained — buyer must add Duo-Seal oil before use. |
