Classic Pump Performance

SCFM X 28.32 = Nl / m
Seconds / 1000 in3 X .61 = Sec. / Liter

SCFM X 28.32 = Nl / m
Seconds / 1000 in3 X .61 = Sec. / Liter

SCFM X 28.32 = Nl / m

sec. / ft3 X 35.32 = sec. / m3

SCFM X 28.32 = Nl / m

sec. / ft3 X 35.32 = sec. / m3

Using the Graphs

Vacuum Flow Rate:
When pump size, operating pressure and desire vacuum level are known:
1.) From the performance graph, read the flow index at the intersection of the performance curve with selected vacuum level line.
2.) Multiply flow index by pump scale to get SCFM flow rate at selected vacuum level.

Example:
ML75 pump @ 72 psi air pressure.
What is vacuum flow rate at 6" Hg?

1.) At intersection of 6" Hg and 72 psi curve, flow index is 4.1.
2.) Pump scale = 3 for size 75 pump. Vacuum flow = 4.1 x 3 = 12.3 SCFM

Air Consumption:
When pump size and operating pressure are known:
1.) From the lower chart, read the consumption index next to the air supply pressure.
2.) Multiply air consumption index by pump scale to get SCFM air consumption.

Example:
ML75 pump @ 72 psi air pressure.
1.) Consumption index - 3.5 at 72 psi.
2.) Pump scale = 3 for size 75 pump. Air consumption = 3.5 X 3 = 10.5 SCFM

Select a vaccum pump:
When vacuum flow rate at a particular vacuum level is known:
1.) From the performance graph, read the flow index at the intersection of performance curve with selected vacuum level line.
2.) Divide required flow rate by the flow index to obtain a minimum pump scale.
3.) Refer to the pump scale chart to select the next larger pump size. This is the smallest pump size that will produce the required flow rate at the desired vacuum level.

Example:
System requires 3.3 SCFM at 15" Hg with 60 psi pump operating pressure.
1.) At intersection of 15" Hg and 60 psi curve, flow index = 1.0.
2.) Minimum pump scale = 3.3 / 1 = 3.3.
3.) From the pump scale chart, the next larger pump scale is 4 which is a size 100 pump that will flow 4 SCFM at 15" Hg for 21% extra capacity. Depending on system variables such as porosity, a larger factor of safety may be desirable.

System Evacuation Time:
1.) Calculate the total system volume in cubic inches by adding together the internal volumes of all system components.
2.) From the chart, find the evacuation time index for the required system vacuum level at the desired pump operating pressure.
3.) Multiply the time index by the system volume then divide by pump scale X 1000 to obtain system evacuation time in seconds.

Example:
1.) For a system volume of 120 in3, a vacuum level of 15" Hg and ML50 pump at 72 psi.
2.) From charts, pump scale = 2. Evacuation time index = 6.6.
3.) Time - 120 X 6.6 / 2 X 1000 = 0.4 seconds.

Pump Specifications
General:
Maximum air supply pressure: 100 psi
Weight: See individual pump pages.
Sound pressure level: ML = 60 - 65 dBA, TML / QML = 70 - 75 dBA

Materials:
Structural parts: 6061 Aluminum (anodized), stainless steel fasteners.
Valve Plate: Type 304 stainless steel.
Ejector: CA360 brass nozzles, delrin plugs.
Silencer: PVC, Urethane.