Bombas Characteristics of Plunger Pumps

ISSN 1068-798X, Russian Engineering Research, 2018, Vol. 38, No. 6, pp. 428–430. © Allerton Press, Inc., 2018.
Original Russian Text © N.L. Velikanov, V.A. Naumov, S.I. Koryagin, 2018, published in Vestnik Mashinostroeniya, 2018, No. 3, pp. 25–27.
Characteristics of Plunger Pumps
N. L. Velikanova, *, V. A. Naumovb, and S. I. Koryagina
aImmanuel
b
Kant Baltic Federal University, Kaliningrad, Russia
Kaliningrad State Technical University, Kaliningrad, Russia
*e-mail: [email protected]
Abstract—The output pressure of a plunger pump is studied experimentally as a function of the productivity.
The corresponding empirical formula is derived.
Keywords: plunger pump, pressure, supply, statistical analysis, empirical formula
DOI: 10.3103/S1068798X18060175
In manufacturing, plunger pumps are used in
power units, hydraulic presses, shaping equipment,
and test benches. Mass-produced plunger pumps with
an eccentric shaft are employed in machine tools. As
the eccentric shafts turn, the plungers resting on their
surface perform reciprocating motion [1–4].
On the basis of dynamic modeling, the operational
efficiency of pumps was studied in [1]. The dynamic
characteristics and efficiency of the system were analyzed. The mathematical model proposed takes
account of nonlinear friction of the piston, hydraulic
losses, and leaking through gaps in the pump.
Pulsation of the output pressure of multiaxial
plunger pumps is of great interest. The pressure pulsations and frequency characteristic were simulated on
the basis of kinematic equations in [2]. The influence
of the number of plungers and the inclination of the
disk edge on the flux pulsations and frequency characteristics of the pump was determined [2].
The reciprocating motion of a hydraulic plunger
pump was simulated in [3]. A model was proposed for
determining the rate of increase in the fuel-injection
pressure for an electronic pump module [3].
Piston and plunger pumps are used for the highpressure transfer of liquids. The plunger in pumps is a
cylinder whose length greatly exceeds its diameter.
Piston pumps are inferior to plunger pumps in numerous respects. The pressure developed by plunger
pumps is higher. The plunger has an external seal at
the entrance to the working chamber and moves without touching the internal chamber walls. (Its guides
are in the drive section.) The speed of plunger pumps
is higher, with corresponding decrease in pump mass
and size [1–4].
In industry, plunger pumps are widely used, especially those with a crankshaft mechanism. Their kinematic system is shown in Fig. 1.
In pump selection, the relation between the output
pressure р and pump supply (productivity) Q is
important. The theoretical р(Q) dependence for a piston pump is a vertical line. In practice, the supply is
somewhat reduced on account of fluid leakage with
increase in the pressure. (See [1], for example.) The
р(Q) dependence of plunger pumps has not been much
studied. In the present work, we analyze experimental
data regarding this dependence for high-pressure
plunger pumps.
Tables 1 and 2 present data for WEIR SPM ТЕМ
2500 and QЕМ 3000 plunger pumps designed for
long-term operation. The model designations distin-
Table 1. Data for TEM 2500 plunger pump [4]
Plunger diameter d, mm
101.6
114.3
127
Pump
Q,
р,
Q,
р,
Q,
р,
L/min MPa L/min MPa L/min MPa
1
247
151
313
119
386
97
2
371
151
469
119
579
97
3
543
151
688
119
849
97
4
741
136
938
107 1158
87
5
1235
81 1564
64 1930
52
6
1384
73 1751
57 2162
46
q, L/turn
4.9
6.6
7.3
Table 2. Data for QEM 3000 plunger pump [4]
Plunger diameter d, mm
101.6
114.3
127
Pump
Q,
р,
Q,
р,
Q,
р,
L/min MPa L/min MPa L/min MPa
1
801
152
1013 119
1251
97
2
988
122
1251
97
1544
78
3
1318
92
1668
72
2059
59
4
1235
73
1564
58
1930
47
5
1977
61
2502
48
3089
39
6
2306
52
2931
41
3603
33
q, L/turn
8.2
10.4
12.9
428
CHARACTERISTICS OF PLUNGER PUMPS
p, kPa
160
429
1
2
120
3
80
40
Fig. 1. Kinetic system of plunger pump with crankshaft
mechanism.
0
p, kPa
160
5
10
15
20
25
30
35
40
Q, L/s
Fig. 3. Dependence of the pressure р on Q for a TEM 2500
three-plunger pump with plunger diameter d = 101.6 (1),
114.3 (2), and 127 mm (3).
120
p, kPa
160
80
40
120
Qmax
Q1
0
5
10
15
20
25
Q, L/s
Fig. 2. Dependence of the output pressure р on the supply
Q for a TEM 2500 three-plunger pump (d = 101.6 mm),
according to experimental data [4] (points) and Eq. (1)
(curve).
In Fig. 2, we show the p(Q) characteristic of the
WEIR SPM TEM 2500 plunger pump (with three
plungers) [4]. We see that, with increase in the supply
Q, the maximum pressure pmax does not change up to
some value Q1. Above that value, the output pressure
declines nonlinearly up to Qmax.
In the range Q1–Qmax , p is almost inversely proportional to Q, according to statistical analysis of the
experimental data in [4]. By the modified leastsquares method, we may select the empirical coefficients. The resulting expression takes the form
Vol. 38
80
40
10
20
30
40
50
60
70
Q, L/s
Fig. 4. Dependence of the pressure р on Q for a QEM 3000
five-plunger pump with plunger diameter d = 101.6 (1),
114.3 (2), and 127 mm (3).
(Tables 1 and 2). In general form, these curves (Figs. 3
and 4) may be described by the formula
⎧ рmax when Q < Q1;
р(Q) = ⎨
⎩ A / Q when Q1 ≤ Q < Qmax .
(2)
Table 3 presents the parameter values according to
Eq. (2). The mean square deviation of the experimenTable 3. Parameter values for Eq. (2)
Plunger pump
Parameter
SPM TEM 2500
SPM QEM 3000
plunger diameter d,
mm
plunger diameter d,
mm
101.6 101.6 114.3 101.6 101.6 114.3
(1)
The р(Q) dependence is obtained analogously for
other plunger diameters and for the QEM 3000 pump
RUSSIAN ENGINEERING RESEARCH
3
0
guish between triplex (T) and quintuplex (Q) systems,
with three and five plungers, respectively. EM pumps
are designed for extended maximum operation. The
figures 2500 and 3000 signify the maximum working
power in horsepower (1866 and 2238 kW, respectively). In Tables 1 and 2, q denotes the output in one
rotation.
⎧151 kPa when Q < 11.12 L/s;
⎪
р(Q) = ⎨1679.4 Q kPa
⎪when 11.12 ≤ Q < 23.06 L/s.
⎩
1
2
No. 6
рmax, MPa
151
119
97
152
119
97
Q1, L/s
11.12
14.11
Qmax, L/s
23.06 29.28 36.03 38.75 49.15 61.06
17.31 13.26 16.93 20.77
A, MPa/(L/s) 1679.4 1679.4 1679.4 2015.1 2015.1 2015.1
2018
430
VELIKANOV et al.
p, MPa
1000
Nuse, MW
2.0
1
1.5
8 and 9
2
10
100
3
11
1.0
7
10
3
1 and 2
0.5
4 and 5
1
0
5
10
15
20
25
30
35
40
Q, L/s
6
0.1
1
2
5
10
Fig. 5. Dependence of the useful power Nuse on Q for a
TEM 2500 three-plunger pump with plunger diameter d =
101.6 (1), 114.3 (2), and 127 mm (3).
20
Q, m3/h
Fig. 6. Dependence of the pressure р on Q for LEWA highpressure plunger pumps [5].
tal data from Eq. (2) is no more than 1.6%. As is evident from Table 3, A does not depend on the plunger
diameter d for a particular pump model, while the
maximum р value is determined by the plunger diameter and does not depend on the number of plungers.
The pump’s useful power Nuse = Qp. Hence
⎧Qрmax when Q < Q1;
N use (Q) = ⎨
⎩ A when Q1 ≤ Q < Qmax .
(3)
According to Eq. (3) and Fig. 5, A corresponds to
max
the maximum useful power N use
(kW) of the plunger
max
pump. For the TEM 2500 pump, N use
= 1679.4 kW,
and the pump efficiency at maximum working power
max
is η = N use
N max = 1679.4 1866 = 0.90.
Table 4. Data for LEWA high-pressure plunger pump with
KA pump head [5]
Theoretical Maximum
flow rate, pressure,
MPa
m3/h
Table 4 presents data for LEWA three- and fiveplunger high-pressure pumps [5]. In Fig. 6, we show
the corresponding р(Q) dependence.
At first glance, it seems that р(Q) is linear from Q1
to Qmax (Fig. 6). However, that is only true in logarithmic coordinates. We find that, for LEWA pumps, the
р(Q) dependence is again described by Eq. (2). The
only difference is in the numerical factors.
The bulk efficiency of high-pressure plunger
pumps may be assumed equal to one, according to the
information on manufacturers’ web sites [4, 5]. This is
indicated by the vertical segment of the characteristic
at the maximum supply (Figs. 2–6). Note that the
р(Q) dependence at the maximum supply deviates
somewhat from the vertical for two-plunger pumps
supplying concrete mixtures, according to experimental data.
REFERENCES
Curve in
Fig. 6
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Translated by Bernard Gilbert
RUSSIAN ENGINEERING RESEARCH
Vol. 38
No. 6
2018