Circulatory Gas Cooled Roots Vacuum Pump DVQB Serise

• • Mechanical shaft seal ensures long service life and superior working performance.
• • Precision synchronous helical gears enable quiet and reliable operation; drive‑end mounting lowers torque load.
• • Optional five‑point mechanical seal delivers zero‑leakage performance.
• • Water‑cooled end cover directly cools seals and extends seal service life.
• • Integrally‑cast rotor & shaft; oversized shaft reduces impeller damage risk.
• • Unique three‑lobe rotor design minimizes vibration and noise.

1. Can it discharge directly to atmosphere?

Yes. Unlike standard Roots pumps, which must be backed by a fore pump, the DVQB exhausts straight to atmosphere – no wastewater, no liquid disposal, no downstream treatment.

2. What pressure difference and inlet pressure can it handle?

Inlet pressure can theoretically reach atmospheric (101.3 kPa). The maximum allowable pressure difference is set by the motor power, not by the pump itself. Shop test (DVQBL-2000.161 unit): stable operation at ΔP 0.06–0.09 MPa with pump temperature steady at 56–78 °C, confirming high-ΔP reliability.

3. Does it need a backing pump? How can it save energy?

Three configurations: stand-alone, multi-stage in series, or combined with liquid-ring / screw backing pumps. Because the DVQB works at high ΔP, the backing pump can be downsized versus a standard Roots unit – significant energy savings. Unit control logic: open the pneumatic valve → start the backing pump → start the Roots pump when pressure reaches the set point (e.g. P ≤ −90 kPa); reverse order on shutdown. The control panel supports set-point start pressure and interlock protection.

4. How is it cooled? What does the site need to provide?

Gas cooling: a heat exchanger on the discharge / bypass line feeds cooling gas into the pump chamber to cool the rotors (no effect on pumping speed), plus water-cooled end covers that lower seal temperature and extend seal life. Site requirement: cooling water to the exchanger and end covers. Typical configuration (DVQB-1100 project): 7 m² SS304 heat exchanger.

5. What seal options are available? Any leakage risk?

Drive shaft: mechanical seal (standard). Rotor shaft: rotary oil slinger seal, mechanical seal or lip seal (optional). An optional five-point mechanical seal achieves zero leakage – ideal for solvent recovery and clean processes. Seal materials: graphite stationary ring, cemented-carbide rotary ring; FKM O-rings (standard), perfluoro rubber or PTFE (optional) for corrosive / high-temperature duty.