Alicat MW-500SLPM WHISPER Low Pressure Drop Mass Flow Meter

The Alicat MW-500SLPM is a WHISPER low-pressure-drop mass flow meter with a 500 SLPM full scale. Its range-specific entry in the Alicat sheet lists a pressure drop of only 0.39 PSID at full scale, 3/4 inch NPT female ports, a body of 5.20 x 2.90 x 5.29 inches and a weight of about 4.5 lb (2.0 kg).

Measuring big flows without choking the line

Most flow meters trade pressure drop for accuracy. The WHISPER MW range is designed for systems with little pressure to spare, such as blower-fed or vacuum-assisted lines; the same 500 SLPM size in the standard M-Series meter drops 4.0 PSID, ten times more according to the M-Series sheet.

The sensor still holds the Alicat specification of 0.8 % of reading plus 0.2 % of full scale, or 0.4 % plus 0.2 % with the high-accuracy option available up to 1000 SLPM, over a 0.01 to 100 % range. The meter shows mass flow, volumetric flow, temperature and pressure and holds 98 gases plus 20 user mixes.

Key features as printed in the datasheet

• Pressure drop 0.39 PSID at 500 SLPM; operating pressure 11.5 to 60 PSIA.
• Accuracy 0.8 % of reading + 0.2 % of full scale; high-accuracy 0.4 % + 0.2 %.
• Pressure accuracy 0.75 % of reading above 1 atm, 0.1 PSIA below 1 atm.
• Totalizer volume uncertainty 0.5 % of reading; temperature sensitivity 0.03 % of full scale per degC.
• Portable MWB version adds Bluetooth Low Energy and a rechargeable battery.

Technical specification

Performance data (WHISPER MW/MWB, 250 to 1000 SLPM sheet)

Mechanical and electrical data

Selection and ordering guide

The WHISPER MW sheet covers 250, 500 and 1000 SLPM (0.60, 0.39 and 0.24 PSID); smaller MW sizes from 0.5 SCCM upward are on separate low and mid sheets. The MWB code is the battery-powered portable version of the same meters.

Because the maximum common-mode pressure is 80 PSIA and differential pressure above 10 PSID can damage the device, WHISPER meters are for low-pressure lines; for higher pressures use the standard M-Series.

For a first installation on a blower line, measure the line pressure at the meter location and compare it to the 11.5 to 60 PSIA operating window before ordering, since the WHISPER body is not intended for the higher pressures that the standard M-Series meters accept. Where the pressure drop budget allows, a straight and clean line with a sintered filter upstream will keep the 3/4 inch ports from collecting debris, and the totalizer can log delivered volume between service intervals.

Installation and operation notes

The Alicat manual for M-series meters states that no straight pipe runs are required and that the meter can mount in any position; only MS and MBS media-isolated sensors need re-taring after an orientation change. For flow ranges of 1 SLPM and above the suggested maximum filter particle size is 50 microns, when pressure drop allows a filter.

Wire the analog output you ordered and confirm the supply range before applying power.

Applications in Oman and the GCC

Low-pressure-drop metering is useful on blower discharge lines, ventilation and combustion-air test rigs, biogas and landfill-gas monitoring, and vacuum-assisted processes. Check that your gas and temperature fall within the sheet limits.

Compatible accessories and related items

Related Alicat items on this site include the MC-100SLPM controller and the M-2000SLPM standard meter, which suits higher line pressures.

Frequently asked questions

What is special about the MW-500SLPM?

It is a WHISPER meter with only 0.39 PSID pressure drop at 500 SLPM full scale.

What is its pressure limit?

Operating range 11.5 to 60 PSIA; damage is possible above 80 PSIA common mode or 10 PSID differential.

What accuracy applies?

0.8 % of reading plus 0.2 % of full scale, or 0.4 % plus 0.2 % with the high-accuracy option.

Is there a portable version?

Yes, the MWB series with battery and Bluetooth Low Energy.

Does Seven Star LLC act as an ALICAT distributor?

No, we are an independent supplier in Muscat and supply ALICAT items on request rather than acting as a ALICAT channel partner.

Documents and quotation

Download the official ALICAT datasheet for MW-500SLPM from this page. As an independent supplier based in Muscat, Seven Star LLC supplies ALICAT items on request: use the quote form with the quantity you need. Check every value in the document against your own specification before you order. Browse similar items in the category.