Calculation Of minimum Inlet Pressure

If the pressure in pump is lower than the vapour pressure of medium, cavitation will occur, which will affect the performance of pump. To avoid the cavitation and ensure the pump inlet has a minimum pressure, maximum suction head should be calculated as following:

H=Pbx10.2-NPSH-Hf-hv-Hs

Pb: Atmospheric pressure, bar (In close pipeline system, it can be considered as the system pressure );
NPSH: Net positive suction head, m (Value at maximum flow of Q-NPSH curve);
Hf: suksesje pipe line ferlies (Wearde by maksimale stream fan passende pipeline);
Hv: Medium vapour pressure, m (Medium vapour pressure at corresponding temperature, the default medium is water, as shown in figure4 on the right );
Hs: Safety margin, m, general value is 0.5.
Berekkingsresultat: as H posityf is, wurdt de pomp yn suksing ynstallearre, oars is it ynstallearre yn 't opslachwei.

Taljochting: It is net nedich om boppesteande berekkening te meitsjen ûnder algemiene betingsten. Allinich as wy pom brûke yn 'e folgjende situaasjes, moatte wy de H:
1. Medium temperature is high;
2.The velocity of flow is larger than rated value;
3.Suction head is big or inlet pipeline is long;
4.System druk is lyts;
5.Inletbedinging is min.

Selection Of Pumps

Selection of pumps should be based on:
Dutypoint fan 'e pomp.
Dimensional data such as pressure loss as aresult of height differences,friction loss in the pipework,
Pump efficiency
Pump materials
Pump connections
Commonly used mechanical seal configuration tables

1. Duty point of the pump:

From a duty point it is possible to select a pump on the basis of the curve charts shown in "performance curves/technical" data.

2. Dimensjale gegevens:

As in pomp oanmeitsje moat de folgjende ynskrift wurde taken: â € ¢ Ferplichte flie en druk op 'e ôfwikselingpunt.â € ¢ Ferwiten ferlies as gefolch fan hichteferskillen. Â € ¢ Friktionferlies yn' e pipework (Hf) (Refer â € ¢ NPSH-wearde. â € ¢ Foar berekkening fan 'e NPSH-wearde sjogge jo oerienkommende korrelsdiagrammen.

3. Pump efficiency:

Foar it bepalen fan 'e bêste effisjinsjepunten moat de operearjen fan' e pomp wurde identifisearre. As it pomp ferwachte wurdt as itselde tsjinstenpunt, selektearje in BL-pompear dy't wurket op in dûbelpunt dat korrespondearret mei de bêste effektiviteit fan 'e pomp.
As de pom is op basis fan 'e heechste mooglike streaming is, is it wichtich altyd om it plichtpunt oan' e rjochter te krijen op 'e effektiviteitskurve (eta) om de effisjinsje heech te hâlden as de stream flugt.

4. Pomp materiaal:

Selection of pump connection depend on the rated pressure and pipe work. the pump offer a wide range of ftexible connection such as:

5. Commonly used mechanical seal seal configurations tables

Application Field

Shaft seal type

Shaft seal material

Normal

Special

1

2

3

4 5

Type kaai

Rotearende diel

Koade

Stasjonele diel

Koade

Elastomers

Koade

Compression spring

Collor

Koade

0℃ to +90℃ clean water

in-

Graphite

IN

SiC

S

FPM

F

SUS304

C

ASFC

0℃ to +90℃ clean water

in-

húske

W

Graphite

IN

FPM

F

SUS304

C

WAFC

+90℃ to +120℃ corrosion resistance

in-

SiC

S

SiC

S

EPDM

E

SUS304

C

SSEC

oant 0â "ƒ

in-

húske

W

húske

W

EPDM

E

SUS304

C

WWEC

Mechanysk seal seal	Pump model	d1	d2	h
NJK	BL (T) 2/4	12	12	55
	BL (T) 8/12/16/20	16	16	57.5
	BL (T) 32/45/60/90	22	22	72
NDA	BW(J)2/4	12.7	16	32
	BW(J)8/16	17.4	20	33.5