Kalkulaasje fan minimale ynljochte presints

As de druk yn pomp leger is as de damp druk fan middel, kavitaasje sil ûntsteane, wat ynfloed op de prestaasjes fan pomp. Om de kavitaasje te foarkommen en te garandearjen dat de pompel ynlaat hat in minimum druk, moat maksimum suksingkop wurde berekkene as folgjend:

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 suksingkop, m (wearde op maximale stream fan Q-NPSH-krom);
Hf: Suction pipe line loss (Value at maximum flow of corresponding pipeline);
Hv: Middellieuze damp druk, m (Middellieuze damp druk by passende temperatuer, it standert medium is wetter, lykas yn figuer4 rjochts);
Hs: Safety margin, m, general value is 0.5.
Calculation result: if H is positive, the pump is installed in suction way, otherwise, it is installed in downdraft way.

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. Middelt temperatuer heech;
2.The velocity of flow is larger than rated value;
3. Súkses kop is grut of ynlieding pipeline is lang;
4.System druk is lyts;
5.Inletbedinging is min.

Selection Of Pumps

Seleksje fan pompen moat basearje op:
Duty point of the pump.
Dimensjale gegevens lykas druk fan ferwûnings as opset fan hichteferskillen, friksjeferlies yn 'e pipework,
Pump efficiency etc.
Pump materials
Pump connections
Faak brûkt meganyske sealtskip tabellen

1. Duty point of the pump:

Fanút in tsjinstpunt is it mooglik om in pomp te selektearjen fan 'e krúmbekken' s sjen litte yn & quot; prestaasjeskurven / technysk & quot; data.

2. Dimensjale gegevens:

When sizing a pump the following must be taken into accounting: •Required flow and pressure at the draw-off point. •Pressure loss as a result of height differences. •Friction loss in the pipework(Hf) (Refer to Fig.1) It may. •Best efficiency at the estimated duty point. •NPSH value. •For calculation of the NPSH value, see corresponding curves chart.

3. Pomp eftergrûn:

Before determining the best efficiency point, the operation pattern of the pump needs to be identified. If the pump expected to operate as the same duty point, then select a BL pump which is operating at a duty point corresponding with the best efficiency of the pump.
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. Pump material:

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 configuration tables

Application Field

Shaft seal type

Shaft seal material

Normaal

Special

1

2

3

4 5

Type kaai

Rotating part

Koade

Stasjonele diel

Koade

Elastomers

Koade

Compression spring

Collor

Koade

0â "ƒ to + 90â" ƒ skjin wetter

in-

Graphite

IN

SiC

S

FPM

F

SUS304

C

ASFC

0â "ƒ to + 90â" ƒ skjin wetter

in-

WC

W

Graphite

IN

FPM

F

SUS304

C

WAFC

+90℃ to +120℃ corrosion resistance

in-

SiC

S

SiC

S

EPDM

E

SUS304

C

SSEC

up to 0℃

in-

WC

W

WC

W

EPDM

E

SUS304

C

WWEC

Mechanical seal type	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