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

Table C4. Pressure loss and air flows through Bosch vacuum Cleaner 9/14/2007 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 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

10.8

-1.4

-4.3

 2.9

 13.874

13.539

11:40am

11:41am

86.24

A

5.2

-0.6

-31.4

30.8

13.015

12.787

60.05

B

5

6.6

-1.5

-25.8

24.3

13.201

12.963

11:49am

11:49am

67.64

A

 3.3

-0.4

-31.2

30.8

12.67

12.495

47.75

B

5

6.5

-0.8

-26.8

26

13.175

12.904

11:56am

11:57am

67.13

A

2.5

-0.3

-45.9

45.6

12.527

12.344

41.46

B

5

3.6

-0.5

-40.5

40

12.704

12.545

12:03am

12:04am

49.90

A

2

-0.2

-48.7

48.5

12.426

12.278

37.00

B

5

2.9

-0.4

-42.9

42.5

12.628

12.461

12:10am

12:11am

44.71

A

1.6

-0.2

-51.5

51.3

12.325

12.194

33.00

B

5

2.2

-0.3

-47.5

47.2

12.476

12.328

12:18am

12:20am

38.84

A

1.2

-0.1

-54

53.9

12.241

12.127

28.48

B

5.4

4.7

-0.5

-33.5

33

13.268

12.746

12:27am

12:28am

57.08

A

1.6

-0.2

-51.3

51.1

12.325

12.211

33.00

Final

3.1

-0.4

-41.4

41

12.687

12.503

12:34am

46.25

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