VMLK

Circular volume flow rate measuring unit made of flame-resistant plastic for the measurement of volume flow rates in variable air volume systems and fume cupboards. Suitable for the permanent monitoring of the volume flow rate (actual value signal) of extract air containing aggressive media since all components coming into contact with the airflow are made of plastic (no interior metal parts). Measurement accuracy ± 5 % even with unfavourable upstream and downstream conditions. Suitable also for volume flow rate control by signalling to frequency converters.

Ready-to-commission unit which consists of the casing with either averaging effective pressure sensor and bluff body or with nozzle, and an electronic controller.

Differential pressure sensor with 3 mm measuring holes (resistant to dust and pollution)

Spigot, suitable for ducts according to DIN 8077.

Casing air leakage to EN 15727, class C.

Special features

• High measurement accuracy with any upstream conditions
• Effective pressure range: approx. 5 – 250 Pa

Materials and surfaces

• Casing made of flame-resistant polypropylene (PP), flame retardant (V-0) to UL 94
• Differential pressure sensor (with bluff body, or nozzle) and plain bearing made of polypropylene (PP)

Technical data

• Nominal sizes: 250 mm
• Volume flow rate range: 30 to 515 l/s or 108 to 1854 m³/h
• Measurement accuracy ± 5 % even with unfavourable upstream and downstream conditions.
• Effective pressure range: approx. 5 – 250 Pa
• Measuring unit differential pressure (pressure loss): 19 – 65 % of the measured effective pressure
• Operating temperature: 10 to 50 °C

Attachments

Volume flow rate control with electronic EASYLAB controller for fume cupboards.

• Supply voltage 24 V AC
• Static differential pressure measurement
• Easy commissioning due to plug and play communication system
• Controller is a modular system and can be expanded
• Volume flow rate monitoring

Sizing data

• V _______________________ [m³/h]

This specification text describes the general properties of the product. Texts for variants can be generated with our Easy Product Finder design programme.

VMLK, LABCONTROL differential pressure transducers

Principal dimensions

ØD [mm]

VAV terminal units made of stainless steel: Outer diameter of the spigot

VAV terminal units made of plastic: Inside diameter of the connecting spigot

ØD₁ [mm]

Pitch circle diameter of flanges

ØD₂ [mm]

Outer diameter of flanges

ØD₄ [mm]

Inside diameter of the screw holes of flanges

L [mm]

Length of unit including connecting spigot

L₁ [mm]

Length of casing or acoustic cladding

B [mm]

Duct width

B₁ [mm]

Screw hole pitch of flange (horizontal)

B₂ [mm]

Outside dimension of flange (width)

B₃ [mm]

Width of device

H [mm]

Duct height

H₁ [mm]

Screw hole pitch of flange (vertical)

H₂ [mm]

Outside dimension of flange (height)

H₃ [mm]

Unit height

n [ ]

Number of flange screw holes

T [mm]

Flange thickness

m [kg]

Weight including attachments for the automatic differential pressure measurement

Nomenclature

V_nom [m³/h] and [l/s]

Nominal volume flow rate (100 %)

V_min [m³/h] and [l/s]

Volume flow rate

ΔV [± %]

Volume flow rate accuracy

K value  [m³/h] and [l/s]

Unit-related constant for air density 1.2 kg/m³

Δp_w [Pa]

Effective pressure

Δp_st [%]

Static differential pressure in relation to the measured effective pressure