2 - Air flow measuring sensors FloXact -Stick

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1 FloXact Stick

2 2.1 - FloXact -Stick Application The FloXact Stick is used to measure air velocity / air volume in HVAC systems. The design allows for easy installation in existing air duct or terminals. The FloXact Stick operates on the pitot tube principle and measures the total and static pressure components of airflow. The sensor determines the average air velocity, measured over 6, 8 or 10 measuring points, depending on the size. The unique shape of the measuring profile creates a linear amplification of at least 2.5x P dyn making accurate measurements from 1,0 m/s possible. Design features Operation of the FloXact Easy installation in existing air ducts or terminals Multi point averaging according to the Log- Tchebycheff method 2% accuracy starting from 1,0 m/s air velocity The unique shape (patent pending) creates a linear amplification of at least 2.5x P dyn. Chamfered entrances to eliminate air direction effects make the FloXact Stick insensitive to approaching multi-directional, rotating airflow with yaw and pitch up to 30º from straight flow. 8 standard sizes ø100, ø125, ø160, ø200, ø250, ø315, ø355 and ø400, other dimensions or sensors for rectangular duct are available upon request. Operating temperature +5 to +95 C Dimensions FloXact -Rxxx L B FloXact - 2

3 2.1 - FloXact -Stick Operation The FloXact -Stick operates on the pitot tube principle and measures the total and static pressure components of airflow. The pressure ports located on the leading surface are sensing the total pressure (Pt) and sensing ports positioned at the rear, sense the static pressure (Ps). The difference between the total pressure and the static pressure is the dynamic pressure (Pd) which relates to the squared air velocity as: P d = ½ x ρ x v 2 P d = dynamic pressure in Pa ρ = density of the gas (air) in kg/m 3 v = velocity in m/s Kv values are based on D nom. = D - 3 mm. The table above is for air with 1.20 kg/m 3 density (20 C, 50% r.h. and 1013 mbar). To simplify mathematics and include the amplification and duct area, the FloXact -Sticks are provided with a K v value. The air volume can be determined with the following formula: Q = K v x P fs Q = air volume in l/s K v = K v value in l/s/pa P fs = pressure difference measured by the FloXact Stick in Pa Model Kv 5,60 9,17 15,62 25,06 38,43 62,85 80,83 103,76 P fs in Pa Air volume in l/s The correction for different densities is determined with the following formula : Corr = (ρ/1.20) FloXact - 3

4 Mounting instructions rectangular units 2 - Air flow measuring sensors FloXact -Stick Duct height H Max 300 Max 150 Duct or unit width W Duct N off H FloXact K v value in l/s/pa ,0 28,8 34,5 40,3 46,0 51,8 57,5 69,1 80,6 92, ,1 41,4 49,7 58,0 66,3 74,6 82,9 99, ,4 51,8 62,1 72,5 82,9 93, ,0 58,7 70,4 82, ,2 69,1 82,9 96, ,4 81,7 98, ,7 92, , The air volume can be determined with the following formula: Q = K v x P fs Q = air volume in l/s K v = K v value in l/s/pa P fs = pressure difference measured by the FloXact Stick in Pa The table above is for air with 1.20 kg/m 3 density (20 C, 50% r.h. and 1013 mbar). The correction for different densities is determined with the following formula : Corr = (ρ/1.20) For intermediate sizes, please contact our office FloXact - 4

5 Mounting instructions Check that the FloXact Stick size corresponds with the duct or terminal were it is installed. The FloXact Stick is mounted in the duct by drilling a ø25mm hole. Check that the air flow direction in the duct corresponds with the arrow on the FloXact Stick. For round ducts, we recommend to install the FloXact Stick diagonally in the duct. This equalises both horizontal and vertical irregular air approach. For non standard applications, please contact our office 2 - Air flow measuring sensors FloXact -Stick Minimum straight duct approach α = <15 Round ducts : D = duct diameter Rectangular ducts : D = 2 x (H x W) / (H + W) Example: W = 600, H = 300 D = 2 x (600 x 300) / ( ) = 400 mm FloXact - 5

6 2.1 - DPT-Flow pressure transmitter FloXact - 6

7 2.1 - DPT-Flow pressure transmitter FloXact - 7

8 2.1 - DPT-Flow pressure transmitter FloXact - 8

9 2.1 - DPT-Flow pressure transmitter FloXact - 9

10 2.1 - FloXact -Stick Type Designation FloXact Stick - R Type size model 100 Round ducts - R to Rectangular ducts - L 1200 Delivery The FloXact Stick is supplied complete with: Gasket 50 cm red and blue PU-tubing ø4/ø6 FloXact - 10