Belt Drive Rotary Vane
Welch DuoSeal belt-drive vacuum pumps
Welch DuoSeal is a family of belt-driven rotary vane vacuum pumps, available in one-stage and two-stage configurations, known for rugged, reliable deep-vacuum performance. The belt-drive design runs at low RPM, which is positioned as quieter, cooler and longer-lasting, and the large oil reservoirs help dilute contaminants for a high tolerance to demanding service.
Choosing a DuoSeal pump+
Choose the 1400 for lower-throughput work and the 1402 where higher pumping speed is needed. Confirm voltage, RPM, oil capacity, dimensions, weight and connection sizes for the exact model before ordering.
When ordering, confirm whether you need a complete pump or a base pump, and add the correct oil (Welch DuoSeal or Gold oil), an exhaust filter and any accessories. Genuine Welch replacement parts and repair kits are available by model, so match the kit to your pump's model and part numbers for a correct fit.
1400 vs 1402 & applications+
Welch 1400 vs 1402 specifications
The DuoSeal 1400 is a two-stage belt-drive rotary vane pump with a pumping speed of about 0.9 CFM, while the 1402 offers about 5.6 CFM; both reach an ultimate pressure near 1×10⁻⁴ Torr. Both operate on 115 VAC single phase in their common configurations and can be ordered with an exhaust filter to control oil mist.
| Model | Pumping speed | Ultimate pressure | Stages |
|---|---|---|---|
| DuoSeal 1400 | ~0.9 CFM | ~1×10⁻⁴ Torr | Two-stage |
| DuoSeal 1402 | ~5.6 CFM | ~1×10⁻⁴ Torr | Two-stage |
Applications, components and compatibility
DuoSeal pumps suit vacuum distillation, vacuum ovens, glove boxes and vacuum manifolds, as well as degassing, freeze drying and backing other pumps.
Related categories
Vacuum Pump Oils Service Kits Accessories Vacuum Oven Vacuum Manifold
FAQs+
What is a Welch DuoSeal vacuum pump?
It is a belt-driven rotary vane vacuum pump from Welch, available in one-stage and two-stage models, known for rugged deep-vacuum performance and a high tolerance to contamination thanks to its large oil reservoir.
What is a belt-drive vacuum pump?
It is a pump in which the motor drives the pumping mechanism through a belt rather than a direct coupling. The belt allows lower operating RPM, which is associated with quieter, cooler and longer-lasting operation.
What is the difference between Welch 1400 and 1402 pumps?
Both are two-stage DuoSeal belt-drive pumps reaching about 1x10-4 Torr. The 1400 has a pumping speed of about 0.9 CFM, while the 1402 offers about 5.6 CFM, so the 1402 evacuates larger systems faster.
What oil should you use in a Welch DuoSeal vacuum pump?
Use Welch DuoSeal oil or Welch Gold oil in DuoSeal belt-drive pumps. Welch notes that using non-Welch oil may void performance claims and warranties; confirm the recommendation in your pump manual.
How do you change oil in a Welch DuoSeal vacuum pump?
In general, the pump is run briefly to warm the oil, switched off, drained into a container, and refilled with the correct Welch oil to the fill mark; Welch recommends a forced oil flush at regular changes. Follow the exact procedure in your pump's owner's manual.
How do you troubleshoot low vacuum on a Welch DuoSeal pump?
Common causes include degraded or contaminated oil, a low oil level, worn seals or vanes, or a leak in the connection. Check and change the oil first, inspect connections, and consult the manual; persistent low vacuum may call for a repair kit or service.
What maintenance schedule is recommended for Welch DuoSeal pumps?
Welch advises inspecting the oil regularly, especially early in a process, and changing it when discoloration or a rising level appears; in clean service, changes can be less frequent. Follow the schedule and forced-flush guidance in the owner's manual.