How to Select a Gas-Liquid Diaphragm Pump: DPGL800 Flow, Vacuum and Build-Up Time

1. Why DPGL800 is not selected like an ordinary liquid pump

DPGL800 is intended for gas and gas-liquid mixtures. Typical duties include aspirating waste liquid with entrained air, evacuating tubing, creating vacuum and continuing to draw when liquid arrives intermittently.

Selection therefore requires more than one flow figure. Define the medium state, target vacuum, permitted build-up time, system volume, discharge pressure, line losses, wetted materials and installation interface. DPGL800-24BS is a 24 V brushless platform operating at DC 24 V ±10% with power consumption of ≤17 W.

2. Information to define before selection

These inputs determine whether 6 L/min and ＜-90 kPa match the real duty.

3. What does 6 L/min mean?

The 6 L/min rating is the single-head, no-load gas-flow capability. It identifies the performance class, but it is neither an actual pure-liquid flow rate nor a fixed installed flow at every vacuum or backpressure.

Flow changes as inlet vacuum deepens or discharge resistance rises. Tubing, valves, fittings, filters, sealing, liquid slugs and the medium state also affect the installed result. Use the curve to locate the required pressure point, then validate the complete system.

4. Core DPGL800-24BS specifications

These fixed limits must remain consistent; confirm material and port-direction details from the complete model code.

5. Reading the gas flow-pressure curve

The curve connects gas flow with pressure. Flow is approximately 6 L/min near zero differential pressure, then changes as inlet vacuum or outlet pressure increases.

Start with the pressure range required by the instrument and read the available flow at that point with suitable margin. The chart illustrates the trend; the formal maximum positive-pressure limit remains 30 kPa.

6. What the 5 L vacuum build-up curve means

This curve records the time needed to build vacuum in a fixed 5 L test chamber and defined test circuit. The final part of evacuation normally takes longer as the pressure approaches the pump's vacuum limit, so time is not a simple linear conversion.

The 5 L value is a test condition, not a capacity, product or application limit. Real 0.5 L, 2 L or 10 L systems behave differently and are also affected by tubing volume, valves, fittings, filters, sealing and leakage.

7. Gas-liquid aspiration versus continuous pure-liquid transfer

DPGL800 fits gas handling, gas-liquid aspiration, waste extraction, line evacuation and vacuum generation. Its 6 L/min value is a gas rating and must not be used as a continuous metered pure-liquid flow.

For stable pure-liquid transfer, compare pumps using liquid flow at pressure, self-priming, pulsation and material compatibility. For a duty with substantial air or high vacuum, validate DPGL800 in the actual gas-liquid circuit.

For a 600 mL/min-class continuous liquid-transfer option, read the DPL60 liquid diaphragm pump selection guide.

8. G1/8 ports, dimensions and port direction

DPGL800 uses G1/8 female threads. Fitting bore, sealing method and line diameter affect restriction and leakage, so the thread designation alone is insufficient. Check the approximately 118.8 mm overall length, mounting holes, approximately 600 g weight and cable clearance before release.

The model code identifies port direction. The drawing shows available thread orientations; the delivered direction must match the confirmed full model and drawing.

9. DPGL800 model coding and interpretation

The complete code defines series, voltage, motor, connection, port direction, wetted materials and special customization.

Example: DPGL800-24BS6-EP/PS

DPGL800 series, 24 V, brushless motor, G1/8 female thread, downward ports, EPDM diaphragm, EPDM valve and PPS head.

10. Complete DPGL800 selection sequence

1. Define the medium

   Record gas-liquid ratio, intermittent slugs, foam, particles and any sustained liquid phase.

2. Set vacuum and cycle time

   State both target vacuum and permitted build-up time, not only ＜-90 kPa.

3. Calculate effective volume

   Include the chamber, tubing, filters, valves and accessories.

4. Define discharge backpressure

   Use the curve to locate the real operating point.

5. Review wetted materials

   Select EP/PS or FF/PS using composition, concentration, temperature and contact time.

6. Choose port direction

   Select 3, 6, 9 or C and check G1/8 fittings, tubing and service space.

7. Check power and life

   Provide DC 24 V ±10% and evaluate ≤17 W and the 10000 h continuous-duty condition.

8. Validate the system

   Test vacuum, build-up time, flow, leakage, noise, temperature rise and gas-liquid transitions.

11. Material combinations and boundaries

Compatibility must cover the entire wetted path, including head, diaphragm, valve, fittings, seals and tubing.

Conclusion

Treat the 6 L/min no-load gas flow, ＜-90 kPa maximum vacuum and 5 L test-chamber build-up time as separate selection inputs. Then apply the real volume, pressure loss, leak rate, medium and material requirements.

Use a liquid diaphragm pump such as DPL60 for continuous pure-liquid transfer comparisons. Use DPGL800 for duties involving air, waste aspiration, evacuation or high vacuum, subject to validation in the actual circuit.

See available configurations, dimensions and downloads on the DPGL800 gas-liquid diaphragm pump product page.

To compare other flow, pressure and medium ranges, return to diaphragm pumps.