MSD - Measurement unit

Airflow measurement unit for circular ducts

This circular airflow measurement unit is available in many sizes.  Accurate measurement based on differential pressure created by measurement probe pipes.

  • Airflow measurement unit based on differential pressure created by measurement probe pipes 
  • Classification of casing leakage EN 1751 class C
  • Inlet and outlet spigots have integral rubber gaskets
  • Airflow transmitter installation allows 50 mm insulation

Accessories

  • Integrated electronic airflow transmitter

The casing of the measurement unit shall be made of galvanised steel.
The measurement probe pipes shall be made of aluminium.
The measurement unit shall have integral gaskets.

Halton MSD

Airflow measurement unit for circle ducts

  • Airflow measurement unit based on differential pressure created by measurement probe pipes 
  • Very accurate measurement, inaccuracy less than ± 10%
  • Classification of casing leakage EN 1751 class C
  • Inlet and outlet spigots have integral rubber gaskets
  • Airflow transmitter installation allows 50 mm insulation
     

Accessories

  • Integrated electronic airflow transmitter
     

Dimensions and Weight

MSD without electronic airflow controller  (MU=NA)

NS  L  L1  ØD 
100  142 75 99
125  142 75 124
160  142 75 159
200  142 75 199
250  142 75 249
315  142 75 314
400  195 125 399
500  195 125 499

 

MSD with electronic airflow controller VRD3 (MU=B)

 

Weight (kg)

NS  MSD-NA MSD-B
100  0.28 0.88
125  0.40 0.95
160  0.46 1.04
200  0.57 1.13
250  0.70 1.27
315  0.87 1.44
400  1.11 1.68
500  1.40 1.97

Material

 Part  Material
 Casing  Galvanised steel
 Measurement probe pipes  Aluminium
 Measurement tubes  PVC and PP plastic
 Duct gaskets  1C-polyurethane hybrid

Function

Airflow in a duct creates a pressure difference between the front and rear probes.

The corresponding airflow rate can be defined by measuring the pressure difference sensed by the two crossing sets of averaging probes.

Installation

In order to ensure the accuracy of the airflow measurement the safety distances between the measurement unit and flow disturbances (e.g. bends, T-branches) have to be respected. The necessary safety distances before and after different disturbances are presented in figures below.

The figure below describes also the recommended axial orientation of measurement probes related to bends and T-branches.

Measurement

Connect the measurement tubes to the manometer and read the pressure difference. The airflow rate is calculated using the formula below or by reading the airflow rate directly from the diagram:

NS k factor
100 5.7
125 9.4
160 17.2
200 27.8
250 43.9
315 72.3
400 127.0
500 200.0

 

Defining flow measurement with electronic transmitter

With model MSD-B air flow can be defined using integrated air flow transmitter VRD3. The actual measured airflow rate (qv) can be defined by the controller feedback signal (U5) and air flow measurement unit's nominal airflow (qv_nom).
 

 Signal  Formula  Controller type and mode  Terminals
 system
 neutral
 Terminals
 signal
  0...10 VDC
 
 qv = qv_nom*U5 / 10  MSD-B
 Mode 0...10V
1(GND)  5 (U5)
  2...10 VDC
 (default set)
 qv = qv_nom*(U5-2) / 8  MSD-B
 Mode 2...10V
1(GND)  5 (U5)

 

Nominal airflow rates of Halton MSD are presented in the table below;Delete Rows

NS qv_nom
100 70 l/s (252 m3/h)
125 115 l/s (414 m3/h)
160 210 l/s (756 m3/h)
200 340 l/s (1224 m3/h)
250 538 l/s (1937 m3/h)
315 885 l/s (3186 m3/h)
400 1555 l/s (5598 m3/h)
500 2449 l/s (8816 m3/h)

 

Wiring

Key:
1 (-)      24 VAC/DC system neutral
2 (+)     24 VAC/DC live
5 (U5)   0...10 / 2…10 VDC actual volumetric flow (
            switchable with ZTH-VAV, 0…100 % Vnom)

Flow controller VRD3

  • Degree of protection: IP40
  • Nominal supply voltage: AC 24 V, 50 / 60 Hz / DC 24 V
  • Nominal supply voltage range: AC 19.2…28.8V / DC 21.6…28.8 V
  • Power consumption: 2 W / 3.5 VA

Specification

The casing of the measurement unit shall be made of galvanised steel.
The measurement probe pipes shall be made of aluminium.

The measurement unit shall have integral gaskets.

Order Code

MSD-D-MU-ZT
 

D   = Connection size
   
     100, 125, 160, 200, 250, 315, 400, 500
 

Other options and Accessories

MU = Electronic controller unit
          NA    Not assigned
          B       Electronic air flow controller unit (VRD3)

ZT = Tailored product
         N        No
         Y        Yes
 

Code example

            MSD-160, MU=NA, ZT=N

Downloads & Media

Halton MSD - fr
Type
Datasheet
Language
French (France)
Size
1.3 MB
Halton MSD - se
Type
Datasheet
Language
Swedish (Sweden)
Size
295.3 kB