Pump Pump sele select ctio ion n acc accor ordi ding ng "Warm "Warman an Slur Slurry ry Pump Pumpin ing g Hand Handb b
1
Input data Solids flow rate
ms =
65
t/h
2
Specific gravity of solids
Ss =
2.65
-
3
Density of liquid
rL =
1000
d50 =
211
kg/m³ mm
Cw
30
%
4 Average 5
Solids concentration
6
Static discharge head
Zd =
20
m
7
Suction head
Zs =
1
m
8
Pipeline length
L=
100
m
9
Suction equiv. lenght
3
m
5 3.35
m
Leq_suc =
11
Number of long rad. 90 elb. N = Lelbow = Elbow equiv. length
12
Temperature
t=
10
°C
13
Pressure
P=
3
bar
14
Pipe material
Mat =
CS
-
15
Pipe nominal diameter
dn =
6
in
16
Pipe schedule
sch =
STD
-
17
Pipe absolute rugosity
18
Pump discharge diameter
19
10
0.1
mm
dp =
100
mm
Loss at pipe discharge
Kexit =
1
-
20
Loss at entrance
Kentr =
0.5
-
21
Height above sea level transmission efficiency
22
Carbon steel pipe selected dn =
6
sch =
STD
di =
particle size
in
Pipe_Imp_CS_Dint_dn_sch
di =
154.1
mm
di =
0.154
m
Rabs =
HASL = htrans =
2700 0.95
m.a.s.l. - (See sheet "Belt")
Limiting settlig velocity d50 = 211 Cv =
13.9
d=
6
SS =
2.65 d50 >= 200 mm 5% <= Cv <= 4
Pipe area A = di = A =
VL=Slurry_Limit_Deposition_Velocity_JRI_Imp_d50_C
(pi()/4) * d i^2 0.154 0.0186
VL =
2.32
m m²
OK. vp > vL Pipe equivalent length Pipe lenght
Slurry velocity vP =
VP / A
VP =
0.049
A =
0.0186
m²
Number of long rad. 90 elb. N= 5
vP =
2.6
m/s
Elbow equivalent lenght
L= m³/s
100
Lelbow = Reynolds
3.35
N-Elbows equivalent lenght v*d/n
Re = v= d= n =
2.62 0.154 1.7E-06
Re =
244,021
LN-lbow =
N *Lelbow
m/ m/s m
N= Lelbow =
5 3.35
m/s²
LN-elbows =
16.75
Total eqivalent length Leq =
Relative rugosity
L + LN-elbows
L=
100
Rabs =
0.1
mm
LN-elbows =
16.75
di = Rrel =
154.08 0.0006
mm -
Leq =
116.75
Kinematic pressure hv = v= hv =
v^2 / (2*g) 2.62
m/s
0.351
m pc
Correction factor HR to express the head
Pump selection
in water column (pump selection)
Select a pump with following QP = 48.9
HR factor Validity Ss :
Hw =
28.2
SP =
1.23
1-6
Cw :
1 1 - 70%
In this case a W arman 6/4 D-
d50 :
20 2 0 - 10000
duty ruber lined pump is sele a 5 vane vane close closed d rub rubbe berr imp impel el
Ss =
2.7
-
Cw =
30
d50 =
211
% mm
HR = HR =
Slurry_HR_factor_Ss_Cw_d50
0.89
pump speed of N=
1130
See sheet "Pump From figure 3.4, the efficienc can be be read as hw = 66
Efficiency on pulp Ep =
Ew * Er
EW =
0.66
HR = W R = Ep =
0.891 0.588
Required NPSH NPSHr = Power P= Equivalent water column Hw =
Hp / HR
Hp = HR =
25.1 0.89
m pc
Hw =
28.2
mwc equiv.
2.8
(1/1 (1/1.0 .02) 2)**Qp*S Qp*S
Qp =
48.9
Sp =
1.23
Hp =
25.1
Ep = htrans =
58.78 0.95
P=
26.51
Selected pump power From sheet Motors P= 30
Resume of pump data Data for pump enquiry Pulp temperature Pulp flow rate Total dynamic head Solids density
t= QP = TDH = rs = rL =
10 48.9 25.1 2650
°C l/s m pc kg/m
3
kg/m %
3
mm
Liquid density Pulp weight concentration
Cw =
1000 30
Specific gravity of solids
Ss =
2.65
Average particle size Froth volume factor
d50 = FVF = NPSHa =
211 0 6.63
Calculated data Pulp Spec. Gravity
Sp =
1.23
-
Pulp volume concentration
Cv =
13.9
%
Pulp kinematic viscosity
np =
1.7E-06
m/s²
Height correction value Efficincy correction value Equivalent water height
HR = HE = Hw =
0.89 0.89 28.2
mwc
Data from selected pump Pump type Motor velocity Efficiency on water
N= Ew =
AH 6/4 1130 0.66
r pm -
Available net press. suc. head
m.p.c.
Efficiency on pulp Power requirement Motor power Required net press. suc. head
Ep = P= P= NPSHr =
0.588 26.51 30
kW kW m.p.c.
ok" [1]
Slurry parameters Pulp density Water absolut
100 r P
C w
100 C w
r s
mw =
r L
t=
rp =
100 / (Cw/rs +(100-C w)/rL )
mw =
Cw =
30
%
rs =
2.65
t/m
3
Pulp viscosity
t/m
3
Ratio of absol
3
mp / mf = (1+2.5*Cv 1
rL =
1
rp = Sp
1.23
t/m
rp =
1230
kg/m³
Cv = mp / mf =
Volumetric concentration C v
mp =
C w
S s
mp / mf =
1 C C w
Cv =
mw =
w
100 * Cw / (Ss* (1-C w) +Cw )
Cw =
0.30
-
Ss=
2.65
-
rL =
1
t/m
Cv =
13.9
%
mp =
Pulp kinemati 3
np = mp = rp =
np =
Slurry mass flow rate m s
m P C w
m s C w
mP =
ms / Cw
ms =
65
t/h
Cw =
0.3
mP =
216.7
t/h
Slurry volume flow rate QP =
mm
m P
mP / rP
mP =
216.7
t/h
rP =
1.23
QP =
176.2
t/m m³/h
QP =
48.9
l/s
Friction factor f=
3
Pressure loss DPexp =
f(Rrel, Re)
%
Rrel =
0.0006
-
K2_ q = 30 =
in
Re =
244,021
-
hv =
-
f= f=
0%
Pipe_Friction_Factor_Rrel_Re
0.0192
DPexp =
Loss at pipe d
Unit pressure los J=
v_dn_Ss
m/s
Exit loss facto Kexit =
f * (1/d) * hv
f= d= hv = J=
0.019 0.154 0.351 0.044
m mpc mpc/ m
Kinematic pre hv = Exit pressure l DPexit = Kexit =
m Frictional pressure loss
m
hv =
Hf =
Leq * J
DPexit =
Leq =
116.75
m
J=
0.044
mpc/m
Loss at entra
Hf =
5.12
mpc
Entrance loss Kentr =
m
Singular pressure drop Loss in discharge pipe enlargement
Kinematic pre hv =
m
Pump discharge diameter
Exit pressure l
dP =
100
DPentr =
mm
Kentr =
pipe diameter di =
154.08
mm
hv =
Gradual expansion ( q = 30°)
m
b = dp / di
m
DPentr =
0.65 Total dynamic Zd =
Pipe_Expansion_Theta30gr_beta
K2_ q = 30 =
1.271
Zs = Hf = DPexp = DPexit = DPentr =
Hp = g=
9.80665
m/s²
Available NPSH results
Atmospheric pressure patm =
l/s mwc AH heavy
101,325* (1 -2,25577E-5 * H)^5,25588
H=
2700
m.a.s.l.
patm =
72,824.8
patm =
6.04
m.p.c.
1
m.p.c.
Pa
Static sucction height Hsucc =
cted with ler at a
Suction pressure loss Frictional pressure loss
rpm
on water %
1
DPf =
Leq * J
Leq_suc = J= DPf =
3 0.044 0.13
Loss at entrance of suction pipe DPentr =
0.18
m mpc/m mpc mpc
Total suction pressure loss DPsuc=
DPf + DPentr
DPf =
0.13
mpc
DPentr =
0.18
mpc
DPsuc=
0.31
mpc
Water saturation pressure m
3
Psat = Exp(ca / tK + cb + cc * tK + cd * tK ^ 2 + ce * tK ^ 3 + cf * Ln(tK))
* Hp /( Ep * htrans)
t= tk = ca = cb =
10 283.2 -5800.2 -5.5
L/s
cc =
-0.05
-
cd =
4.2E-05
mpc
ce =
-1.4E-08
% -
cf = Pw_vap =
6.5 1.228
kPa
kW
Pw_vap =
1228
Pa
Pw_vap =
0.102
m.p.c.
kW
4
NPSHa = NPSHa =
°C K
Patm + Hsuc - DPsuc - Pw_vap 6.63
m.p.c.
Rev. cjc. 30.01.2014
1
1 e viscosity SaturatedWaterAbsoluteViscosity_t
10 1.3E-03
°C Pa s 2
ute viscosities (Thomas)
0.05*Cv^2+0.00273*Exp(16.6*Cv))
0.1392 1.57 mp / mw * mw
1.57
3
1.3E-03
Pa s
2E-03
Pa s
c viscosity
4
mp / rp 2.0E-03
Pa s
1229.7
kg/m³
1.7E-06
m/s² 5
6
7
2 in expansion K2_ q = 30 * hv 1.271
0.351
mpc
0.45
mpc
ischarge
r 1
-
ssure 0.351 loss Kexit * hv
mpc
1 0.351
mpc
0.35
mpc
ce to suction pipe
factor 0.5
-
ssure 0.351
mpc
loss Kentr * hv 0.5
0.351
mpc
0.18
mpc
head 20 -1 5.12 0.45
mpc mpc
0.35
mpc
0.18
mpc
25.1
mpc
3
P
Q p
l S H mpc s P p 1.02 h p %
kW
and with transission efficiency
l S H mpc s P p P 1.02 h p %h trans Q p
4
kW
3
m s TDH Pa W P h m3 Q TDH mmwc s P g h m3 Q TDH mwc s P g 1000 h m3 Q S P TDH mpc s W P g 1000 h m3 Q S P TDH mpc s g 1000 kW P h 1000 m3 Q S P TDH mpc s kW P g h m3 Q S P TDH mpc s kW P g 100 h % l Q S P TDH mpc g 100 kW P s h % 1000 l Q S P TDH mpc g kW P s h % 10
4
3
Q
P
1 10
l Q S P TDH mpc s h %
kW
g
P
P
Q p
Q p
P
l S TDH mpc s P 1.02 h % l S H mpc s P p 1.02 h p %
Q p
kW
kW
l S H mpc s P p 1 .02 h p %
kW
l S H mpc s P p P kW 1.02 h w ER % l Q p S P H w HR mpc s P kW 1.02 h w ER % l Q p S P H w mpc s P kW 1.02 h w % Q p
Pump calculation according "Warman Slurry Pumping Handbook"
Slurry parameters
[2]
Slurry density 100 r P
C w r s
rP =
100 C w
[2] (1-4)
r L
100 / (Cw/rs +(100-C w)/rL )
Carbon steel pipe selected dn = 6 in sch = STD di = Pipe_Imp_CS_Dint_dn_sch di =
154.08
mm
di =
0.15408
m
Cw =
30
%
rs =
2.65
t/m
3
rL =
1
t/m
3
rP =
1.23
t/m
3
Pipe area A =
(pi()/4) * d i^2
di = A =
0.15408 0.0186
Slurry velocity vP =
VP / A
VP =
0.049
m m²
Slurry mass flow rate m s
m P C w
m P
m s C w
mP =
ms / Cw
ms =
65
t/h
A=
0.0186
m²
Cw =
0.3
-
vP =
2.6
m/s
mP =
216.7
t/h Limiting settlig velocity d50 = 211
mm
Slurry volume flow rate VP =
mP / rP
mP =
216.7
t/h 3
rP =
1.23
VP =
176.2
t/m m³/h
VP =
48.9
l/s
Cv =
d=
6
in
SS =
2.65
-
d50 >= 200 mm
1 C C w
2.32 OK. v > vL
m/s
w
100 * Cw / (Ss* (1-C w) +Cw )
0.30
%
Ss=
2.65
t/m
3
rL =
1
3
Cv =
13.9
t/m %
Friction head Hf for the pipeline Pipe equivalent length Pipe lenght L= 100
m
Elbow equivalent lenght Lelbow = 3.35
LN-elbows =
16.75 Total eqivalent length L + LN-elbows Leq = 100
1230
kg/m³
Kinematic viscosity n = m / r 2.0E-03
Pa s
1229.7
kg/m³
1.7E-06
m/s²
m
N-Elbows equivalent lenght LN-lbow = N *Lelbow 5 3.35
Slurry density r =
m = r = n =
Number of long rad. 90 elb. N= 5
L=
%
VL =
Cw =
N= Lelbow =
13.9
VL=Slurry_Limit_Deposition_Velocity_JRI_Imp_d50_Cv_dn_Ss
C w
S s
Cv =
5% <= Cv <= 40% cualquier diámetro
Volumetric concentration
C v
m³/s
m m
Reynolds Re = v= d= n = Re = Relative rugosity
v*d/n 2.62 0.15408
m/s m
1.7E-06 244,021
m/s²
LN-elbows =
16.75 116.75
Leq = Slurry properties t= P=
10 3
m m
°C bar
Water absolute viscosity
mw =
SaturatedWaterAbsoluteViscosity_t
mw =
1.3E-03
Pa s
Pulp viscosity Ratio of viscosities (Thomas) mp / mf = (1+2.5*Cv 10.05*Cv^2+0.00273*Exp(16.6*Cv))
Rabs = di = Rrel =
0.1 154.08 0.0006
Friction factor f= f(Rrel, Re) Rrel = 0.0006 Re = 244,021 f=
mm mm -
-
Pipe_Friction_Factor_Rrel_Re
f=
0.0192
Kinematic pressure (r/2) * v^2 hv = r = 1229.70
-
kg/m³
Cv =
0.1392
v=
2.62
m/s
mp / mf =
1.57
hv =
4236.3
Pa
mp =
mp / mw * mw
mp / mf =
1.57
mw =
1.3E-03
Pa s
mp =
2E-03
Pa s
Unit pressure los J= f * (1/d) * hv f= 0.019 d= 0.15408 hv = 4236.3 J= 528.8
Kinematic pressure hv = v^2 / (2*g) v= 2.62 g= 9.81 hv = 0.351 Pa/m Pressure loss in expansion K2_ q = 30 * hv DPexp =
Pressure loss Hf = Leq = J= Hf = Hf = Hf =
Leq * J 116.75 528.8 61,736 6295 6.30
K2_ q = 30 = m Pa /m Pa mmwc mwc
Pressure loss in msc Hf [msc] = Hf [mwc] / Ss Hf = 6.30 mwc Ss = 1.23 kg/m³ Hf = 5.12 msc Loss in discharge pipe enlargement Pump discharge diameter dP =
100
mm
pipe diameter di =
m/s m/s² msc
154.08
mm
hv = DPexp =
1.271 0.351 0.45
msc msc
Loss at pipe discharge Exit loss factor Kexit =
1
Kinematic pressure hv = 0.351
-
msc
Exit pressure loss DPexit = Kexit * hv Kexit =
1
hv =
0.351
msc
DPexit =
0.35
msc
Gradual expansion ( q = 30°) b = 0.65 Pipe_Expansion_Theta30gr_beta
K2_ q = 30 =
1.271
Loss at entrance to suction pipe
HR factor
Entrance loss factor Kentr =
0.5
-
Kinematic pressure hv = 0.351 Exit pressure loss
Ss :
Validity 1-6
Cw :
1- 70%
d50 :
20 - 10000
msc Ss =
2.7
% mm
DPentr =
Kentr * hv
Cw =
30
Kentr =
0.5 0.351 0.18
d50 =
211
hv = DPentr =
msc msc
Total dynamic head Zd = 20 Zs =
HR = HR =
Slurry_HR_factor_Ss_Cw_d50
0.891
Equivalent water column Hw = Hm / HR
Hf = DPexp =
-1 5.12 0.45
Hm = HR = Hw =
DPexit =
0.35
msc
DPentr =
0.18
msc
Let
Hm =
25.09
msc
Hw =
msc msc
Correction factor HR to express the head in water column (pump selection)
25.1 0.891 28.2
28.2
mwc equiv.
mwc
Pump selection Select a pump with following results VP = 48.9 l/s Hw =
28.2
mwc
Ss =
2.65
-
In this case a Warman 6/4 D-AH heavy duty ruber lined pump is selected with a 5 vane closed rubber impeller at a pump spedd of N= 1130 rpm See sheet "Pump From figure 3.4, the efficiency on water can be read as
hw =
P
l Q S P TDH msc s 1.02 h m %
with TDH = and h=
kW
P
l Q S P Hwmsc s 1.02 h w% P= Q= SP =
Hm hm
Index "m": mixture (pulp)
P
l Q S P Hmmsc s 1.02 h m %
kW
kW
48.9 1.23 28.2
hw =
66 25.2
l/s mwc kW
Also, the power can be expresses as
with
l Q S P TDH msc s 1.02 ER h w %
Hm =
Hw * HR
P
hm =
hw * ER
where hw is the water equivalent
and
l Q S P Hw HRmsc s P 1.02 h w ER%
%
(1/1.02) * Q * Ss * H w / hw
Hw = P=
66
kW
pump efficiency, read from performance curve for (Q, and Hw)
kW
as HR is assumed equal to HR
P
l Q S P Hw HRmsc s
P
1.02 h w HR%
l Q S P Hwmsc s 1.02 h w %
Power
kW
kW
m3
l
m3 TDH Pa Q s P h P m3 N Q TDH s m2 P h P m Q TDH N s P h P Nm Q TDH s P h P J Q TDH s P h P Q TDH W P h P ____ ____ __ ______
P
s
a
P
W
h P
m3 TDH mmwc s P g h P m3 TDH mwc Q s P g 1000 h P m3 S P TDH msc Q s W P g 1000 h P m3 S P TDH msc Q s g 1000 kW P 1000 h P m3 S P TDH msc Q s kW P g h P m3 S P TDH msc Q s kW P g 100
s 1.
Q
%
h P
P
l Q S P TDH msc s 1000 h P %
g 100
l S P TDH msc g s P Q
%
10
P
P
g 10 1 10
kW kW
h P
l S P TDH msc s Q
%
kW
h P
l S TDH msc P s Q
%
h P
kW
g
l S P TDH msc s P 1.02 h P % Q
kW
P
g 100 3600
g P Q
36
m3 h P Q
3.
Rev. cjc. 30.01.2014
Solids flow rate
ms =
65
t/h
Specific gravity of solids
Ss =
2.65
-
Average particle size
d50 =
211
Solids concentration
Cw
30
%
Static discharge head
Zd =
20
m
Suction head Pipeline length Number of long rad. 90 elb.
Zs =
1 100 5
m m
L= N=
mm
Kinematic pressure hv = v^2 / (2*g) v= 2.62 g= 9.81 hv = 0.351
m/s m/s² msc
Unit pressure los J= f * (1/d) * hv f= d= hv = J= Pressure loss Hf = Leq = J= Hf =
0.019 0.154 0.4 0.044
Leq * J 116.75 0.044 5.12
m mwc mwc/ m
m msc/m msc
Pump curves have TDH expressed in mwc.
P
msc
2 h %
kW
m3 S P TDH msc h kW h % 3 S P TDH msc h kW h %
Q
S P TDH msc 67 h %
kW
To be able to use the pump curve for the calculated TDH "Hm [msc]", Weir presents following relation
H w
H m HR
where HR is always less than 1. Thus, for the given flow rate, the equivalent water TDH "Hw" is always larger than the calculated value Hm [msc] With the actual flow rate and with the equivalent water height the efficiency on water can be obtained from pump curve
3.670978367
1
2
3
4
Warman slurry correction factors HR and ER Pump power
Example calculation of the using the function. The validity range of the inp are: Ss : 1-6
The power is given by m3 TDH Pa s h
Q P
W
(Eq. a)
With a unit transformation, l Q S P H w mpc s P 1.02 h w %
Cw :
1- 70%
d50 :
20 - 10000
Let us assuming following d
kW
where hw is the water equivalent
(Eq. f)
Ss =
2.7
Cw =
30
d50 =
211
HR = HR =
Slurry_HR_factor
0.891
pump efficiency, read from performance curve and Hw = Hm / HR where "Hm" is the calculated TDH Hm = TDH [mpc] and "HR" is the corretion factor given by Figure 2-3
Let, as an example TDH = 25.1 and with HR = 0.891 the water equivalent head is Hw = 28.17
Following data is required Ss: Specific gravity of solids [- ]
Let also the pulp flow rate b Q= 48.9
Cw : Weight concentration [%] d50 = Average particle size [ mm] The HR factor can be read from Figure 2-3 and also can be evaluated using the function "Slurry_HR_factor" as shown in the example
W ith this information, the op to be used with the pump pe curves diagram of the selec Q= 48.9 Hw = 28.17 In the selected pump diagra equivalent pump efficency c estimated to be hw = 66
Rev. cjc. 30.01.2014
R factor
Example of power calculation
t parameters
With the help variables calculated, the power can be calculatres as follows Q * SP * Hw / (1.02 * hw) P= P: Power [kW] Q: Pulp flow rate [l/s]
ata
SP : Pulp specific gravity
-
Hw : Water equivalent head [mwc]
% mm
hw:Water equivalent pump efficiency
Ss_Cw_d50
mpc
mwc
l/s
erating point rformance ed pump is l/s mwc m, the water an be %
Q= Assume SP =
48.9
l/s
1.23
-
Hw =
28.17
mwc
hw =
66 25.17
% kW
P=
H (m) 50
40
30
20
10
0 0
Rev. cjc. 30.01.2014
In this case a Warman 6/4 D-AH heavy duty ruber lined pump is selected with a 5 vane closed rubber impeller, with QP = 48.9 l/s Hw = At this point, N= Ew = NPSHr =
1350 rpm
28.2
mwc
1130 66 2.8
rpm % m
60%
65%
70%
77.5%
70%
1300 rpm
66 %
1200 rpm 1130 rpm
28.2 mwc
1100 rpm 1000 rpm
2.5 m
3.0m
NPSH 4.5 m
48.9 l/s
20
40
60
80
100
Q L/s
120
http://oee.nrcan.gc.ca/regulations/products/14297
Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Power (HP) 1 1.5 2 3 4 5 5.5 7.5 10 15 20 25 30 40 50 60 75 100 125 150 175 200 250 300 350 400 450 500
Power (kW) 0.75 1.1 1.5 2.2 3 3.7 4 5.5 7.5 11 15 19 22 30 37 45 55 75 90 110 132 150 185 225 260 300 335 375
Corresponds to Table 2 in the CAN/CSA C390-1 Energy Efficiency Standard (Perc Open 2 Pole 4 Pole 6 Pole 8 Pole 2 Pole 75.5 82.5 80 74 75.5 82.5 84 84 75.5 82.5 84 84 85.5 85.5 84 84 86.5 86.5 86.5 85.5 84 86.5 86.5 86.5 85.5 85.5 87.5 87.5 87.5 87.5 85.5 87.5 87.5 87.5 87.5 87.5 88.5 88.5 88.5 88.5 88.5 89.5 90.2 89.5 89.5 89.5 91 90.2 89.5 90.2 90.2 91 91 90.2 90.2 91 91.7 91.7 90.2 91 91 92.4 92.4 91 91 91.7 93 93 91 91.7 92.4 93 93 91.7 92.4 93 93.6 93.6 92.4 93 93 94.1 93.6 93.6 93 93 94.1 94.1 93.6 93.6 93.6 94.5 94.1 93.6 94.5 93.6 95 94.5 93.6 94.5 94.5 95 94.5 93.6 95 94.5 95 94.5 93.6 95 94.5 95.4 95.4 94.5 95.4 95 95.4 95.4 95.4 95 95.4 95.4 95.4 95.4 95.4 95.4 95.8 95.8 95.4 95.8 95.8 95.4
ntage) Enclosed 4 Pole 6 Pole 8 Pole 82.5 80 74 84 85.5 77 84 86.5 82.5 87.5 87.5 84 87.5 87.5 84 87.5 87.5 85.5 87.5 87.5 85.5 89.5 89.5 85.5 89.5 89.5 88.5 91 90.2 88.5 91 90.2 89.5 92.4 91.7 89.5 92.4 91.7 91 93 93 91 93 93 91.7 93.6 93.6 91.7 94.1 93.6 93 94.5 94.1 93 94.5 94.1 93.6 95 95 93.6 95 95 94.1 95 95 94.1 95 95 94.5 95.4 95 95.4 95 95.4 95.4 95.8 -
http://www.vanmeterinc.com/assets/files/pdf/3.20VBeltsSynchronicBelts.EdHubble.pdf
3 V Narrow d h =
4 95
in %
B Classical d h =
4 94
in %
