Table D4. Pressure loss and air flows through Dust Director vacuum cleaner 10-04-2007 Round 2

Before (B) or after (A) adding 5 pounds

Total weight of debris transferred (lb)

Venturi meter δP (inches of water)

Static Pressure Measurements with manometer (inches of water)¹

Absolute pressures measured with pressure transducers (psi)

Time to start loading

Time to stop loading

Air flow (cfm)

Pressure in vacuum cleaner bag (inches of water)

Pressure after the bag (inches of water

Pressure after first filter (inches of water)

Pressure after second filter (inches of water)

Pressure after the bag (psi) 87614

Pressure after first filter (psi) 53748

Pressure after second filter (psi) 55481

B

5.4

7.5

-6.3

-7.1

-14.4

-18.8

14.127

13.623

13.453

3:47pm

3:48pm

72.07

A

6.2

-4.4

-17.8

-28.2

-32.4

13.776

13.197

12.973

65.57

B

10.2

6

-4.2

-17.9

-30

-33.4

13.81

13.063

12.906

3:56pm

3:58pm

64.51

A

4.4

-2.2

-30.8

-43.9

-47.1

13.551

12.578

12.434

55.22

B

15.2

4.5

-2.2

-25.9

-42.7

-45.7

13.634

12.595

12.46

4:06pm

4:07pm

55.85

A

3.3

-1.9

-36.2

-52.2

-54.8

13.467

12.244

12.123

47.75

B

20.2

4.1

-2.5

-28.9

-46.5

-49.3

13.576

12.461

12.333

4:15pm

4:16pm

53.29

A

2.15

-2

-41.9

-57.6

-59.8

13.242

12.06

11.963

38.39

B

25

4.55

-3

-25.9

-42.5

-45.6

13.609

 12.595

12.451

4:23pm

4:24pm

56.16

A

2.5

-1.35

-44.9

-59.1

-61.2

13.083

12.002

11.921

41.46

B

30

3.7

-2.2

-33.3

-49.2

-51.9

13.392

12.344

12.224

4:34pm

4:35pm

50.59

A

2.4

-1.4

-45.8

-59.4

-61.7

13.233

12.002

11.887

40.61

B

35.4

3.2

-1.65

-38.8

-54.8

-57

13.359

12.169

12.039

4:44pm

4:45pm

47.01

A

1.35

-0.9

-51.6

-63.9

-65.4

13.551

11.826

11.727

30.25

Final

 35.4

3.4

-1.65

-38.5

-54

-56.9

13.484

12.177

12.039

4:50pm

48.47

¹ Static pressure is the difference in pressure from atmospheric pressure. These static pressures are less than atmospheric pressure.