The Effects of Debris Accumulation Upon Air Flow and Filter Resistance to Air Flow for Four Commercially Available Vacuum Cleaners

Table C3. Pressure loss and air flows through Bosch vacuum Cleaner 9/14/2007 Round 1

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 loading

Time to stop loading

Air flow (from venturi meter) (cfm)

in bag

after bag

δP bag

between bag & filters (55481)

after final filters (53748)

B

5

11.5

-1.1

-2.2

1.1

13.95

13.631

9:12am

9:14am

88.92

A

3.5

-0.5

-40

39.5

12.695

12.545

49.19

B

5

8.6

 -0.9

-18.8

17.9

13.436

13.147

9:26am

9:28am

77.11

A

2.3

-0.7

-46.6

45.9

12.476

12.361

39.73

B

5

3.9

 -0.4

-38.2

37.8

12.796

12.603

9:37am

9:39am

51.96

A

1.9

-0.3

-49.5

49.2

12.392

12.244

36.04

B

5

5.4

 -0.6

-29.8

29.2

13.049

12.821

9:49am

9:50am

61.20

A

2.6

-0.3

-45

44.7

12.535

12.403

42.30

B

5

3.1

 -0.3

-42.3

42

12.628

12.461

9:58am

9:59am

46.25

A

1.9

-0.2

-48.9

48.7

12.409

12.269

36.04

B

5

2.3

 -0.4

-47.1

46.7

12.493

12.328

10:10am

10:12am

39.73

A

1.3

-0.2

-53.8

53.6

12.224

12.136

29.67

B

5

1.9

 -0.2

-49.9

49.7

12.359

12.253

10:26am

10:28am

36.04

A

1.1

-0.1

-56.4

56.3

12.157

12.077

27.24

Final

1.5

-0.2

-52.9

52.7

12.283

12.169

10:35am

31.93

¹ Static pressure is the difference in pressure from atmospheric pressure. Negative static pressure indicates that pressure is less than atmospheric pressure.