ข้อสอบสามัญเครื่องกล Pump 3/2549

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5 (Pump / Fan / Compressor) 3/2549

2 1 36 (X)

( 1 ) ( 36)1. (N

S) (Axial Flow)

. 500 < NS

< 1,500

. 2,000 < NS < 6,000. 7,000 < N

S< 20,000

. 20,000 2. (Suction) Foot Valve

. . . .

3. Cavitations. casing

.

. . suction lift

4. Cavitations . NPSHA > NPSHR. NPSH

A< NPSH

R

. NPSHA = NPSHR

. 5. Shop test

. .

.

.

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6. .

. . .

7. . . . (system head).

8. (Discharge) Check Valve . . . .

9. . . . valve .

10. cavitations . suction lift.

. . . .

11. 100 30 75% 85%

. 46.14 kW. 36.14 kW

. 26.14 kW. 16.14 kW

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12. (Net Positive Suction Head, NPSH)

. . . .

13. 100 7 15 3.50 23.00 7.00 75% 90%

. 46.14 kW. 118.97 kW. 167.65 kW. 197.97 kW

14. 100 3.50 1.75 50 3 / 300 42.15 15 21.00 80% 70% 2

. 51.68 kW. 64.76 kW. 71.11 kW. 81.11 kW

15. 150 / 4.50 5.00 16.75

75%

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. 41.50 kW. 51.50 kW

. 61.50 kW. 71.50 kW

16. 960 / 125 / 30 52.55 kW 1,450 ()

. 181.07 kW. 175.00 kW. 160.50 kW. 140.00 kW

17. Inverter (Hertz) 50 Hz 30 Hz 50 Hz 250 / 42 kW ( 4 Poles)

. 5 kW. 9 kW. 12 kW. 16 kW

18. 200 / 20.00 1,450 / 380 150 / 15.75

. 290 . 300 . 320 . 347

19. 150 / 20.00 1,450 250

24.00 ()

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. 177 /. 187 /

. 197 /. 207 /

20. (Mixed Flow). H . H

Q Q

. H . H

Q Q

21. 3 ../ 75 60% 85%

85%. 2.75 kW. 3.24 kW. 3.45 kW. 4.38 kW

22. 15 ../ 150 40

20 55% 90%

. 3.46 kW. 4.54 kW. 6.36 kW. 7.42 kW

23. 20 ../ 100 100

4 kW 25 ../

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. 4.52 kW. 5.15 kW

. 6.12 kW. 7.81 kW

24. 40 ../ 250 60% 85% 400 25 kW Overload

. 43 ../

. 46 ../. 48 ../. 50 ../

25. 150 ../ 100 450 200 ../

. 500 /. 600 /. 650 /. 750 /

26. 200 ../ 4 50 kW 1500 50 Hertz Inverter 15 Hertz

. 40.00 kW. 25.75 kW. 15.15 kW. 1.35 kW

27. Built up Coil 450 ../ 250 450 ../ 100

2 55%

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. 250 kW. 275 kW

. 327 kW. 375 kW

28. 2 35../ 70 ../ 65% 200 2

. 32.30 kW. 42.30 kW. 52.30 kW. 55.30 kW

29. Class

. .

.

.

30. (Specific Speed)

. Forward

. Backward

. Propeller Fan. Axial Fan

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5 31. - 35.

Pump 230 m3

/hour 30o

C

(water density 1,000 kg/m3

) Center Line Pump 2.5 m Center Line Pump 4.5m. Foot Valve 1 2 m Suctionloss 0.67 m Check Valve 1 Gate Valve (Fully Open) 1 Long Radius Elbow 3 8 m Discharge line loss 0.8 m Steel Pipe Schedule 40 2m/s 3 m/s.

31. Net Suction Head Pump. 3.37 m. 2.37 m. 0.34 m. 2.50 m

32. Net Discharge Head Pump. 5.30 m. 5.76 m. 0.58 m. 4.50 m

33. Net Pump Operating Head. 8.67 m. 7.00 m. 9.13 m. 29.6 m

34. Pump Power Pump 75%. 8.55 kW. 9.71 kW

. 8.21 kW

. 7.63 kW

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35. Motor Motor 93%

. 8.21 kW. 8.83 kW. 10.44 kW. 9.19 kW

36. Centrifugal Pump 36 cu.m/hr Total Head 80 m 2,000 rpm Pump Power 10 kW Pump 78% Pump 3,000 rpm

Total Head Pump Power 3,00 rpm (5)()

1. Q2/Q1 = n2/n1

Q2 = Q1*( n2/n1) = 36*3000/2000

= 54.0 m3/h

2. H2/H1 = (n2/n1)2

H2 = H1*(n2/n1)2

= 80 * (3000/2000)2

= 180.0 m

3. P2/P1 = (n2/n1)3

P2 = P1*(n2/n1)3

= 10*(3/2)3

= 33.75 kW

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2 3 1.1. 1 (5 )

. . . . .

1.2 (5 )

. . . . .

1.3 () (5 )

. 78 . 21 . 0.93 . 0.06 . Neon, Helium 0.01

1.4 1.013 1,800 7 () (5 )

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PgPoPoCoVr+

= 3


Vr = (..)

Po = ()Pg = ()Co = (../)

- Po = 1.013 - Pg = 7.0 - Po + PG = 8.013 - Co = 25 ../- Vr = 11.4 ..

2. 2.1 (Water Hammer) (5 ) 2.2 Water Hammer (5 ) Water Hammer2.3 Water Hammer (5 ) Water Hammer

- (Critical Time TC)

-

-

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2.4 Water Hammer 3 (5 )

- Pressure Relief Valve

- Air Inlet-relief Valve

- Air Chamber

- Surge Suppressor

- Surge Tank

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ข้อสอบสามัญเครื่องกล Pump 3/2549