Estimate a theoretical swept volume from condensed liquid, injection water and gas flow already expressed at pump-suction conditions. This simplified volume balance uses a fixed liquid density and an assumed volumetric efficiency; it does not determine condenser vacuum or select a pump.
Independent Jet Condenser Pump Interactive Calculator
Explore mixture-volume arithmetic and theoretical swept displacement per stroke under explicit density, efficiency and gas-volume-basis assumptions.
Equation Used
- All entered steam mass is fully condensed and combined with injection water at mass ratio r.
- Combined liquid uses fixed specific volume 0.0167 ft³/lb regardless of temperature.
- Entered gas volume is already actual volumetric flow at pump suction conditions and is directly additive to liquid volume.
- No water vapor, partial pressures, saturation, heat balance, condensation, vacuum, gas compression, valve timing, clearance volume, slip, NPSH/cavitation, pump geometry, power, structure or safety model.
The fixed liquid specific volume is 0.0167 ft³/lb (about 59.9 lb/ft³). Entered air volume must already be expressed at the same pump-suction pressure and temperature basis; the calculator does not convert free-air, mass flow, water vapor or vacuum conditions.
Illustrative liquid-plus-gas volume balance
Condensed mass and injection-water mass are combined and multiplied by a fixed liquid specific volume. A separately entered gas volume at pump-suction conditions is added to obtain a combined volume rate.
Dividing by entered volumetric efficiency and stroke rate gives required geometric swept volume per stroke. The animation is a qualitative piston-volume cue, not a vacuum-pump cycle.
Relate flow to assumed displacement
The calculation shows how flow, stroke rate and assumed volumetric efficiency affect theoretical swept volume. It cannot determine condensation, air leakage, vacuum, valve area, cylinder dimensions, power or capacity.
Volume bases must match
Liquid volume is ms(1+r)vliq with fixed vliq=0.0167 ft³/lb. Gas volume can be added only when already stated at the pump's actual suction state. Free-air volume at atmospheric conditions is not interchangeable.
Required geometric swept rate is Qmixture/eta_v; it exceeds mixture rate whenever eta_v<1.
Worked example
At 50 lb/min condensed mass, injection ratio 30, entered gas volume 4 ft³/min, eta_v=0.75 and 45 strokes/min, combined volume rate is 29.885 ft³/min. Required swept rate is 39.847 ft³/min, or 0.8855 ft³ (6.62 US gal) per stroke.
Conditions needed for pump selection
Pump selection requires the actual suction pressure and temperature, noncondensable gas and vapor loads, discharge conditions and the pump’s performance data. Condensation and cooling-water demand need a separate heat balance. The entered efficiency and fixed liquid density are assumptions, so this displacement result alone does not establish capacity, power or operating limits.
Questions
Can atmospheric free-air volume be entered directly?
No. Gas volume must be converted to the pump-suction pressure and temperature basis.
Does this calculate vacuum?
No. Pressure and thermodynamic state are absent.
Does swept volume select a pump?
No. Valve dynamics, clearance, speed limits, power and ratings are not checked.
References & Further Reading
- Wikipedia contributors. Surface condenser. Wikipedia
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