of self-priming centrifugal pumps selection - John Brooks Company

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G O R M A N - R U P P

P U M P S

SELECTION & APPLICATION OF SELF-PRIMING CENTRIFUGAL PUMPS

PUMP SELECTION To assist with the selection of self-priming pumps, we have created the following hypothetical example. We believe the problem and its solution to be typical of a job that might confront engineers and users. We shall assume there is a requirement for a wastewater collection system that will require a lift station to pump the wastewater to a pretreatment collection system. The following data were acquired by actual accurate measurements.

SYSTEM REQUIREMENTS Flow:

GRpumps.com

S E L F - P R I M I N G

P E R F O R M A N C E

G O R M A N - R U P P

P U M P S

SELECTION & APPLICATION OF SELF-PRIMING CENTRIFUGAL PUMPS

SYSTEM CONDITIONS Static Suction Lift 15' (4.6 m) vertical distance from low liquid level to center line of pump suction. Suction Pipe 17' (5.2 m), 4" (100 mm) C.I. pipe. Measured from end of suction pipe to pump suction. 90° L.R. elbow and 45° elbow equivalent to 11.5' (3.5 m) of 4" (100 mm) C.I. pipe (for friction loss calculation).

Pump Drain Kit

PUMP SELECTION To assist with the selection of self-priming pumps, we have created the following hypothetical example. We believe the problem and its solution to be typical of a job that might confront engineers and users. We shall assume there is a requirement for a wastewater collection system that will require a lift station to pump the wastewater to a pretreatment collection system. The following data were acquired by actual accurate measurements.

Static Discharge Head 7.5' (2.3 m) vertical distance from center line of pump suction to invert of discharge outlet. Discharge Pipe 500' (152.4 m), 4" (100 mm) C.I. pipe. Measured from pump discharge outlet. 90° L.R. discharge elbow, check valve and gate valve equivalent to 49.8' (15.2 m) of 4" (100 mm) C.I. pipe (for friction loss calculation). Priming Lift 10' (3.0 m) measured from high liquid level to center line of pump suction.

SYSTEM REQUIREMENTS Flow: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 gpm (12.6 lps) Solids: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3" (76 mm) Configuration: . . . . . . . . . . . . . Duplex, one pump for standby Site Elevation: . . . . . . . . . . 5280' (1609.3 m) above sea level

The accumulation of the preceding data now permits calculating the Total Dynamic Suction Lift (TDSL), Total Discharge Head (TDH), and Net Positive Suction Head (NPSH) using the worksheets on the following pages.

G O R M A N - R U P P

1

HOW TO COMPUTE THE TOTAL DYNAMIC HEAD (TDH)

TOTAL DYNAMIC SUCTION LIFT: A + B = C A. Static Suction Lift

15.00' (4.6 m)

P U M P S

S E L E C T I N G

F E1

P U M P

G O R M A N - R U P P

P U M P S

S E L E C T I N G

E2

D

H 5.7' (1.7 m)

6.8' (2.1 m) 26' (7.9 m) 17' (5.2 m) 49.8' (15.2 m)

CENTER LINE OF PUMP SUCTION

17.00' (5.2 m)

N

B2

2. Fittings in Equivalent Length of Pipe a. One 90° L.R. Elbow, 4"–6.8' (100 mm–2.1 m) 11.50' b. One 45° Elbow, 4"–4.7' (100 mm–1.4 m) (3.5 m) 3. Total Pipe (Actual & Equivalent)

R I G H T

ATMOSPHERIC PRESSURE 500' (152.4 m) 4" (100 mm) C.I. PIPE

B. Friction, Suction (Consult Hydraulic Handbook) 1. Pipe, Total Length, 4" (100 mm) C.I.

T H E

4.3' (1.3 m)

L

6.8' (2.1 m) 4.7' (1.4 m) 11.5' (3.5 m)

28.50' (8.7 m)

9.3' (2.8 m)

M 5' (1.5 m)

.90' (.27 m)

4. Total Friction Loss (.285' × 4.43' × .71') (.09 m × 1.4 m × .22 m) (based on friction coefficient C = 100, 4.43/100' and correction factor to C = 120 = .71)

10' (3.0 m)

C. Total Dynamic Suction Lift

15.90' (4.8 m)

A

B1

P

C

J

G

K

28.2' 33.9' −18.9' (8.6 m) (10.3 m) (−5.7 m)

TOTAL DISCHARGE HEAD: D + E = F D. Static Discharge Head

7.50' (2.3 m)

PUMP STARTS

E. Friction, Discharge or Force Main Line (Consult Hydraulic Handbook) 1. Pipe, Total Length, 4" (100 mm) C.I. 2. Fittings in Equivalent Length of Pipe a. One 90° L.R. Elbow, 4"– 6.8' (100 mm–2.1 m) b. One Check Valve, 4"– 26' (100 mm–7.9 m) c. One Plug Valve, 4"– 17' (100 mm–5.2 m) 3. Total Pipe (Actual & Equivalent)

500.00' (152.4 m)

5' (1.5 m)

49.80' (15.2 m)

NOTE: Suction pipe must be properly supported.

549.80' (167.6 m)

PUMP STOPS

17.30' (5.3 m)

4. Total Friction Loss (5.5' × 4.43' × .71') (1.7 m × 1.4 m × .22 m) (based on friction coefficient C = 100, 4.43/100' and correction factor to C = 120 = .71) F. Total Dynamic Discharge Head

24.80' (7.5 m)

TOTAL DYNAMIC HEAD: C + F = TDH C. Total Dynamic Suction Lift

15.90' (4.8 m)

F. Total Dynamic Discharge Head

+24.80' (7.5 m)

Total Dynamic Head

40.70' (12.4 m)

2' (.6 m)

NOTE: Suction pipe must be properly supported.

T H E

R I G H T

P U M P

G O R M A N - R U P P

1

HOW TO COMPUTE THE TOTAL DYNAMIC HEAD (TDH)

P U M P S

S E L E C T I N G

T H E

2

ATMOSPHERIC PRESSURE 500' (152.4 m) 4" (100 mm) C.I. PIPE

F E1 E2

H

N 4.3' (1.3 m)

HOW TO COMPUTE THE NET POSITIVE SUCTION HEAD (NPSH)

9.3' (2.8 m)

10' (3.0 m)

C

J

3

P U M P S

S E L E C T I N G

T H E

R I G H T

P U M P

SELECTING THE CORRECT PUMP

G

K

G. Atmospheric pressure (at sea level)

33.90' (10.3 m)

H. Atmospheric pressure corrected to 5280' (1609 m) [site elevation]

– 5.70' (–1.7 m)

J. Atmospheric pressure available at job site (G–H)

M 5' (1.5 m)

1. Total dynamic suction lift

15.90' (4.8 m)

2. Vapor pressure 74° liquid

1.00' (.30 m)

3. Safety factor (may vary based on local regulations)

2.00' (.61 m)

K. Total net deductions from available atmospheric pressure (1+ 2+ 3)

– 18.90' (–5.7 m)

L. NPSH Available (J – K) 28.2' 33.9' −18.9' (8.6 m) (10.3 m) (−5.7 m)

28.20' (8.6 m)

Deductions from available atmospheric pressure:

L

6.8' (2.1 m) 4.7' (1.4 m) 11.5' (3.5 m)

P

G O R M A N - R U P P

Detailed Computation

B2

B1

P U M P

5.7' (1.7 m)

6.8' (2.1 m) 26' (7.9 m) 17' (5.2 m) 49.8' (15.2 m)

CENTER LINE OF PUMP SUCTION

A

R I G H T

M. NPSH Required (see performance curves)

PUMP STARTS

N. NPSH Excess Available, or excess atmospheric pressure (L– M)

9.30' (2.8 m) – 5.00' (–1.5 m) 4.30' (1.3 m)

NOTE: Items M and N cannot be determined until pumps are selected. 5' (1.5 m)

and is the band our selected pump will operate within from the beginning to the end of the pumping cycle. NOTE: Suction pipe must be properly supported.

PUMP STOPS 2' (.6 m)

NOTE: Suction pipe must be properly supported.

HOW TO DETERMINE THE PRIMING LIFT P. Priming lift

CONCLUSION: 10.00' (3.0 m)

NOTE: Priming lift is measured from the high liquid level to the center line of the pump suction. Priming lift has no relation to net positive suction head.

Model T4AS-B pump, equipped with a 9-3/4" (250 mm) diameter impeller, turning at 1150 RPM, is the correct selection.

Taking all this information into consideration, the best course of action is to select a 7½ HP (5.6kW) motor to ensure non-overloading operation throughout the pump’s operating range.

S E L E C T I N G

T H E

2

HOW TO COMPUTE THE TOTAL DYNAMIC HEAD (TDH)

R I G H T

P U M P

G O R M A N - R U P P

HOW TO COMPUTE THE NET POSITIVE SUCTION HEAD (NPSH)

3 Detailed Computation

SELECTING THE CORRECT PUMP

P U M P S

S E L E C T I N G

Capacity

REPRIMING LIFTS RP 650 750 850 950 1050 FEET 5 8 16 19 22 METERS 1,5 2,4 4,9 5,8 6,7 Figure NPSH required prior to using above table. DO NOT use as available Suction Lifts.

PSI

FT

60

140

56

130

Total Dynamic Suction Lift (TDSL)

15.90' (4.8 m)

Priming Lift

10.00' (3.0 m)

Net Positive Suction Head (NPSH) Available

9.30' (2.8 m)

HOW TO DETERMINE THE PRIMING LIFT P. Priming lift

IMP.DIA.

1.0

SP.GR.

RP

9-3/4"

VARIOUS

55

40

1050

A

15[

C

950 850 750 20 6 50

]

NPSH

9]

FT

11,

B

2]

7,5]

10 8 20 6 4 10 2 0 0

100 64 23

95 60 22

56

85

90

21

20

80

52 19

18

17

48

75

5,6]

44

70

7.5[

16

65 15

40

60 14

55 36

13

50

]

32

45 28

The 3" (76 mm) spherical solids requirement suggests a model T4AS-B. A typical Super T curve is shown. A 9-3/4" (250 mm) diameter impeller, turning at 1150 RPM, would be the correct selection. This is a standard motor on 60 cycle frequency. It may be flex-coupled to the pump; however, for versatility, it may be v-belt driven. Note NPSH requirement of 5' (1.5 m) well within the available NPSH of 9.30' (2.8 m). The priming characteristic of the 9-3/4" (250 mm) diameter impeller at 1150 RPM is 24' (7.3 m) (see priming performance data on each curve). We require only 10' (3 m) of priming lift.

]

3[2,2

12

9

10

40

35

]

24

30

X 10

2[1,5

1[,75]

11

[email protected]

5[3,7

M

30

10[

20

0

P[ 20 , ,6] 9KW

14,

30

0

BH

20[

1150

CUBIC METRES PER HOUR X 10

NOTE: Suction pipe must be properly supported.

SIZE

1250

50

10

LITRES PER SECOND

4" x 4"

[18

8

60

4

U.S.GALLONS PER MINUTE

T4AS-B

OPER AT RANG ING E 50

45

7

0

8

MODEL

1350

25

4

12

10528

28

16

8

16

IMPELLER

25

6

20 12

T4AS-B-4

1450

70

20

24

CURVE

1550

80

5

28

90

15

32

10525B

55

12

36

VOLUTE

1650

4

16

100

40

40

0

10

20

110 17 50

8

24

48 44

35

3

28

120

5

32

M

185

52

3" (76 mm)

Note: Select performance within operating range of curve.

0 RP

4

36

195

1

40

P U M P

PERFORMANCE CURVE

1150 1250 - 1950 24 25 7,3 7,6

3.00"/[76,2] DIA. MAX. SPHERICAL SOLIDS

2

44

0

M

R I G H T

40.70' (12.4 m)

Spherical Solids

TOTAL HEAD

T H E

200 gpm (12.6 lps)

Total Dynamic Head (TDH)

After you’ve made the necessary calculations, you are ready to choose the correct pump for the application.

0

1

P U M P S

0

G O R M A N - R U P P

T-2-98-R

CONCLUSION: Model T4AS-B pump, equipped with a 9-3/4" (250 mm) diameter impeller, turning at 1150 RPM, is the correct selection.

fl is the band our selected pump will operate within from the beginning to the end of the pumping cycle. NOTE: Suction pipe must be properly supported.

Taking all this information into consideration, the best course of action is to select a 7½ HP (5.6kW) motor to ensure non-overloading operation throughout the pump’s operating range.

G O R M A N - R U P P

1

P U M P S

S E L E C T I N G

T H E

2

HOW TO COMPUTE THE TOTAL DYNAMIC HEAD (TDH)

R I G H T

P U M P

HOW TO COMPUTE THE NET POSITIVE SUCTION HEAD (NPSH)

G O R M A N - R U P P

3

P U M P S

S E L E C T I N G

T H E

R I G H T

4

SELECTING THE CORRECT PUMP

P U M P

SELECTING THE CORRECT MOTOR

Calculating the correct motor size for a pump involves the use of a complicated formula. To make this process easier, many manufacturers add horsepower (or kilowatt) lines to their performance curves. Referring to point on the curve, the closest non-overloading horsepower line represents 5 brake horsepower (BHP) or 3.7kW. A good rule of thumb to use when selecting motors is to apply a motor which will provide sufficient power to cover the entire length of the selected pump curve (a practice which results in a “non-overloading” motor selection). Using our example, the selected operating speed of the pump is 1150 RPM. The performance of a pump will follow along this speed curve but will vary due to normal pump wear and changes in sump level. The calculation below accounts for the sump level change between the pump on and off levels.

TDH AT THIS LEVEL 35.70' (10.9 m) PUMP STARTS

40.70' (12.4 m) –5.00' (–1.5 m)

5'

35.70' (10.9 m) or: 36' (11.0 m) TDH at point

on curve.

TDH AT THIS LEVEL 40.70' (12.4 m) See on curve. PUMP STOPS

The change shown above is basically a change in static head. The actual performance of the pump is illustrated on the curve where the 1150 RPM curve and hydraulic system curve intersects (this is noted on the curve as point ). The difference in flow rate between points and is the band our selected pump will operate within from the beginning to the end of the pumping cycle.

2'

NOTE: Suction pipe must be properly supported.

NOTE: Suction pipe must be properly supported.

HOW TO DETERMINE THE PRIMING LIFT

Taking all this information into consideration, the best course of action is to select a 7½ HP (5.6kW) motor to ensure non-overloading operation throughout the pump’s operating range.

S E L F - P R I M I N G

P E R F O R M A N C E

SELF-PRIMING | THE SENSIBLE SOLUTION Self-priming pumps are a sensible solution for industrial and municipal applications. They require very little attention, resulting in significant savings of maintenance time and money.

CHOOSE FROM A FULL LINE OF SELF-PRIMING CENTRIFUGAL PUMPS Drive Variations:

Gorman-Rupp self-priming pumps are available as basic units for connection to your power source or may be flex-coupled, v-belt driven or engine mounted.

Automatic priming means dependable performance. All that’s needed is an initial priming and the pump will continue to reprime automatically. In fact, our trash handling pumps will reprime with only a partially filled pump casing and a completely dry suction line! Our reputation for quality has made Gorman-Rupp the world’s leader in self-priming centrifugal pumps. In addition, it makes us your best solution – meeting all of your industrial or municipal waste handling needs.

Ultra V Series®

Super T Series®

Super U Series®

High-Heads Solids-Handling

Solids-Laden Liquids and Slurries

High Efficiency Solids and Corrosive Liquids

Ultra V Series ® self-priming, centrifugal trash pumps handle 200% more pressure and provide 60% increased flow. Self-cleaning features, reduced footprint and unique configuration capabilities allow these pumps to excel in high-head situations where traditional pumps fall short.

Super T Series ® pumps feature a large volute design which allow them to reprime automatically in a completely open system without the need for suction or discharge check valves – nd they can do it with the pump casing only partially filled with liquid and a completely dry suction line.

Super U Series ® self-priming pumps are among the most efficient solids-handling, self-priming pumps available (up to 75%). Open, multivane impeller will handle solids up to 1-1/4" (31.8 mm) in diameter.

Size: 3" (75 mm) to 6" (150 mm) Max. Capacity: 1900 gpm (123 lps) Max. Head: 168' (51 m) Max Solids: 3" (76.2 mm)

Size: 2" (50 mm)* to 10" (250 mm) Max. Capacity: 3400 gpm (214.5 lps) Max. Head: 130' (39.6 m) Max Solids: 3" (76.2 mm)

Size: 3" (75 mm) to 6" (150 mm) Max. Capacity: 1500 gpm (95 lps) Max. Head: 207' (63.1 m) Max. Solids: 1.25" (31.8 mm)

80 Series®

10 Series®

Solids and Corrosive Liquids

Clear Liquids

80 Series ® self-priming pumps are designed for high-efficiency, nonstop workloads. Straight-in suction design allows them to operate on higher suction levels than standard self-priming centrifugals.

10 Series ® self-priming pumps have only two moving parts – impeller and shaft – so maintenance problems are minimal.

0 Series ® self-priming pumps feature straight-in suction which eliminates entrance restrictions and provides better suction performance when handling solvents, petroleum products and similar liquids.

Size: 1.5" (37.5 mm) to 12" (300 mm) Max. Capacity: 6000 gpm (378.6 lps) Max. Head: 170' (51.8 m) Max. Solids: 3" (76.2 mm)

PUMP SELECTION To assist with the selection of self-priming pumps, we have created the following hypothetical example. We believe the problem and its solution to be typical of a job that might confront engineers and users. We shall assume there is a requirement for a wastewater collection system that will require a lift station to pump the wastewater to a pretreatment collection system. The following data were acquired by actual accurate measurements.

SYSTEM REQUIREMENTS Flow:

* 2" available in T Series only

Size: 1.25" (32 mm) to 10" (250 mm) Max. Capacity: 2800 gpm (177 lps) Max. Head: 205' (62 m) Max. Solids: 2.5" (60.3 mm)

OF SELF-PRIMING CENTRIFUGAL PUMPS

Gorman-Rupp self-priming centrifugal pumps are easy to install and easy to service. Because they’re self-priming, they can be mounted high and dry at floor level with only the suction line in the liquid – there’s never a need for service personnel to enter the sump. When service or maintenance is required, it can be completed easily with common hand tools. There are no long drive shafts to install and align, and no hoists or cranes are required.

• Basic • V-Belt • Flexible Coupled • Engine-Driven

Limited Solids and Corrosive Liquids

SELECTION & APPLICATION

0 Series®

Size: 2" (50 mm) to 6" (150 mm) Max. Capacity: 1350 gpm (85.2 lps) Max. Head: 400' (121.9 m) Max. Solids : .688" (17 mm)

E L E M E N T S

O F

A

5

P U M P I N G

S T A T I O N

G O R M A N - R U P P

P U M P S

7

16

8 6 4

9

Although the pump is the heart of a pumping station, other elements should be considered when designing a system. This example identifies some of the items that can make up a system.

1 3 15

2 17

10

12

11 13

1. 2. 3. 4. 5. 6. 7.

Pump (2) Discharge Pipe Suction Pipe 3-Way Valve (1) Air Release Valve (2) Discharge Check Valve (2) Gauge Kit – Suction and Discharge (2)

8. 9. 10. 11. 12. 13. 14.

Control Panel Electric Motor (2) Base Inlet Pipe Discharge/Force Main Sump/Wet Well Suction Flare L.R. 90° Bend or Flange & Flare 15. Entrance to Sump/Wet Well 16. Pump Station Enclosure 17. Pump Drain Kit

SYSTEM CONDITIONS Static Suction Lift 15' (4.6 m) vertical distance from low liquid level to center line of pump suction. Suction Pipe 17' (5.2 m), 4" (100 mm) C.I. pipe. Measured from end of suction pipe to pump suction. 90° L.R. elbow and 45° elbow equivalent to 11.5' (3.5 m) of 4" (100 mm) C.I. pipe (for friction loss calculation). Static Discharge Head 7.5' (2.3 m) vertical distance from center line of pump suction to invert of discharge outlet. Discharge Pipe 500' (152.4 m), 4" (100 mm) C.I. pipe. Measured from pump discharge outlet. 90° L.R. discharge elbow, check valve and gate valve equivalent to 49.8' (15.2 m) of 4" (100 mm) C.I. pipe (for friction loss calculation).

14

SOLD AND SERVICED THROUGHOUT THE WORLD

Priming Lift 10' (3.0 m) measured from high liquid level to center line of pump suction.

Gorman-Rupp has nearly 1,000 distributors worldwide who are qualified to give expert advice on pump selection and application. If you have a service problem, a factory-trained distributor is only a phone call away. Our distributors are backed by the fastest parts service in the industry so your parts will be there when you need them.

Gorman-Rupp Pumps Mansfield, Ohio, USA Manufacturing Facilities Distribution Centers

Gorman-Rupp Canada St. Thomas, Ontario, Canada

Gorman-Rupp Europe Leeuwarden, Netherlands Gorman-Rupp Africa Cape Town, South Africa Durban, South Africa Johannesburg, South Africa (Headquarters)

Distribution Centers Bangkok, Thailand Dubai, United Arab Emirates Grand Prairie, Texas, USA Leeuwarden, Netherlands Sparks, Nevada, USA

ISO 14001:2004

AV-004857_REV032015

Product information is subject to change; consult factory for details. ©2009-2015 The Gorman-Rupp Company. All rights reserved. Printed in the USA

The accumulation of the preceding data now permits calculating the Total Dynamic Suction Lift (TDSL), Total Discharge Head (TDH), and Net Positive Suction Head (NPSH) using the worksheets on the following pages.

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of self-priming centrifugal pumps selection - John Brooks Company

S E L F - P R I M I N G P E R F O R M A N C E E L E M E N T S O F A P U M P I N G S T A T I O N G O R M A N - R U P P P U M P S SELECTION & A...

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