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
  • Air flow transmitter installation allows 50 mm insulation

PRODUCT ACCESSORIES

  • Integrated electronic air flow 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.

Overview

Halton MSD

Airflow measurement unit for round 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
  • Air flow transmitter installation allows 50 mm insulation
     

Accessories

  • Integrated electronic air flow transmitter
     


 

Weight and Dimensions


DIMENSIONS

MSD-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-B (with electronic airflow controller VRD3)



Weight

NS  Weight( kg )  Weight( kg ) 
  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


MATERIAL

PART  MATERIAL 
Casing Galvanised steel
Measurement probe pipes Aluminium : Measurement tubes PVC and PP plastic
Duct gaskets 1C-polyurethane hybrid


Function


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


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


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.


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 air flow rates of the MSD are presented in the table below.
 

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




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


SUGGESTED SPECIFICATIONS


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.

Product Code


PRODUCT CODE


MSD-D-MU

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

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


Code example

   MSD-160-B

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