External Gear Pump Parameter Calculation Sheet2.972 Understanding How Things Work

Group ?Date: ?

Value Variable Dimension How To Get It

No. of Teeth 11 [ N ] teeth You Choose

Pitch (Diametral) 6.93 [ p ] 1 / in = N/PD

Pressure Angle 30.0 [ f ] degrees Usually Standard (14.5, 20, 25, 30)

Adendum Diameter 1.875 [ AD ] in = PD + 2*a

Dedendum Diameter 1.226 [ DD ] in = PD - 2*d

Pitch Diameter 1.587 [ PD ] in You Choose

Adendum 0.144 [ a ] in = 1.00/p

Dedendum 0.180 [ d ] in = 1.25/p

Minimum Number of Teeth to Avoid Undercut Input to Omax Waterjet Software

For No For Acceptable No. TeethPressure Angle Undercut Undercut

degrees # teeth # teeth Pitch

14.5 32 20 Pressure Angle20.0 18 1425.0 12 10

Input Values in BLUE, Do NOT Change Values in RED

Usually Standard (14.5, 20, 25, 30)

Input to Omax Waterjet Software

11 teeth

6.93 1 / in

30.0 degrees

Calculation For Gear Pump FlowBy: Martin L. CulpepperDate: 01/02/99

General Input: Data For an Exact ConditionDisplacement 0.50 in3/rev Shaft Speed 500 rpmPressure Change 100 psi Slip Flow 1.5 in3/sSlip Flow Coefficient 0.015 --- Ideal Flow 4.2 in3/s

Actual Flow 2.7 in3/shv 0.64 ---

Data For Graphs

Shaft Ideal Slip Actual VolumetricSpeed Flow Flow Flow Efficiency

w Qi Qs Qa hv

0 0.00 1.50 -1.50 N/A500 4.17 1.50 2.67 0.64

1000 8.33 1.50 6.83 0.821500 12.50 1.50 11.00 0.882000 16.67 1.50 15.17 0.912500 20.83 1.50 19.33 0.933000 25.00 1.50 23.50 0.943500 29.17 1.50 27.67 0.954000 33.33 1.50 31.83 0.96

Enter Values in BLUE, values in RED are calucated and should not be changed!

0 500 1000 1500 2000 2500 3000 3500 4000 4500-5

0

5

10

15

20

25

30

35

40

0.00

0.20

0.40

0.60

0.80

1.00

External Gear Pump Flow Characteristics

Ideal Flow

Slip Flow

Actual Flow

Volumetric Efficiency

Shaft Speed, w, rpm

Flo

w,

Q,

in3/s

Vo

lum

etr

ic E

ffic

ien

cy,

nv