Low NPSH vertical and horizontal pumps

dp pumps

the dynamics of water

low-NPSHr dpv & dph(s)i Prevent cavitation and pump failure

low-NPSHr unique

Cavitation is caused by too low suction

pressure, in relation to the internal resistan-

ce of the liquid in the pump and the vapor pressure of a liquid (the higher the temperature, the higher the vapor pressure). In case

Also with higher flows

of cavitation pump problems occur because

DP’s unique design allows for lower NPSHr overall,

of imploding ‘bubbles’ generating an inten-

but also extends the low NPSHr to higher flows

se shock wave. Life expectancy decreases

where conventional pumps normally see a sharp

because of deteriorating of the metal and

increase in NPSHr with resultant cavitation.

extra wear on moving parts due to imbalance and decreased cooling and lubricating

No increased motor power

properties of the cavitating liquid. Without

Although the low NPSHr impellers would normally

cavitation you are assured of a quiet and

require slightly more power than the standard impel-

long-lasting smooth pumping.

lers, there will be no requirements for increased motor power due to efficient rimming of the low NPSHr components.

DP has developed a specially designed low NPSHr impeller and bottom stage casing to

Low NPSHr impeller versus standard Impeller

create a pump range with significant lower

n Inlet

NPSHr values. Due to this low NPSHr design

n The

the pump can be used in a wider range of

n Impeller

applications where low suction pressure and/

n Modified

or high vapor pressure of the liquid normally

n Total

cause problems

be compensated by the adjusted

diameter of the impeller is larger impeller opening height is increased base plate has been reinforced vane design

height of the impeller is larger, this will

bottom casing n Hot

water (Boiler feed)

n Feed

from a (low) reservoir

n Little

to no space between the deaerator tank

and the pump n No

vented tanks available

dphi

2

dpvcf

dpvsf

dpv

design Low NPSHr impeller

Extended CFD calculation models have resul-

A pump with Low NPSHr impeller has the same

ted in a design with lower fluid velocities at the

height as the standard version and can easily

core of the impeller (shown in blue).

be exchanged.

0 12

Standard impeller

20

0

10

IM.gpm

40

US.gpm 20

30

40

60

0

50

0

20

US.gpm 20

40

60

80

40

IM.gpm

100

60

80 2900 rpm

2900 rpm

DPV 10 B Low NPSHr

DPV 15 B Low NPSHr

14

10 Förderhöhe TDH Hauteur Prevalenza Opvoerhoogte Altura

30

m 8

ft

Low NPSH

6

Förderhöhe TDH Hauteur Prevalenza Opvoerhoogte Altura

20

40

12 m 10

ft

8

Standard Low NPSH

Standard

0

2

m³/h

0

4

6 l/s

1

8

10

2

12

0

14

3

Standard

NPSH3%

2 Low NPSH

0 = 1000.0 kg/m³

0

2

m³/h

4

6

8

Fördermenge/Flow/Débit/Portata/Capaciteit/Caudal

10

12

14 20161450/0

m³/h

10

15 l/s

2

20

4

ft

= 1000.0 kg/m³

15

Standard

m

ft

2

0

0

25

25 6

4

10

m NPSH3%

0

4

4

5

Low NPSH

0

5

m³/h

10

15

Fördermenge/Flow/Débit/Portata/Capaciteit/Caudal

20

25 20161652/0

Low NPSHr option is available for DPV (C/S) and DPH(S)I 2, 4,6, 10 and 15 in both 50 and 60 Hz

3

0

dp pumps P.O. Box 28 2400 AA Alphen aan den Rijn Holland t +31 172 48 83 88 f +31 172 46 89 30 dp@dp-pumps.com www.dp-pumps.com

97013926/0717