PWM Paddle Wheel Meter

Product catalog summary

Specifications
The paddle wheel flow meters have an accuracy of ±1% FS, a maximum temperature of 60°C (140°F), and a maximum pressure of 10 barg (150 psig). They require a power supply of 5 to 24 Vdc at 2 mA and provide an NPN open collector output signal with a load capacity of 30 mA max. The dimensions are 56H x 108L x 53D mm (2.2 x 4.25 x 2.2 inches) without RTD and flow sensors. The flow signal cable is 1.8 m (6 ft) or optionally 3.7 m (12 ft), and the RTD cable is 12 inches long. The RTD is a platinum type with a 0.00385 TCR, compliant with EN 60751, Class B.

Materials
The wetted materials for the flow meters include a polypropylene or PVDF body, an acrylic or PVDF lid, a PVDF paddle wheel, a nickel tungsten carbide or zirconia ceramic shaft, sapphire jewel bearings, and EPDM or PTFE O-rings. The platinum RTD is encased in 316 stainless steel.

Flow Rate
The flow meters are available in different sizes with varying flow rates and pressure drops. For example, the PWM4 model has a flow rate of 0.15-18.9 L/min (0.04-5 gal/min) with a 3/8" inlet/outlet port and a maximum pressure drop of 1 bar (15 PSI).

Model Numbers
The model numbers vary based on the material and the inclusion of an RTD. For instance, the PWM4P is a polypropylene model, while the PWM4PR includes an RTD.

Principles of Operation
The flow meters operate by having fluid flow through the unit, causing the paddle wheel to spin. Magnets embedded in the paddle generate electrical pulses as they pass the sensor, with the frequency of these pulses being proportional to the flow rate. The flow rate and volume can be calculated using the number of pulses and the K-factor.

Design Features
These flow meters are designed for liquid flow applications and feature jewel bearings for low minimum flow rates, easy installation and operation, horizontal or vertical mounting, and a single moving part. They provide flow indication via a transparent acrylic cover and a versatile square wave flow output signal. The meters have female NPT ports and offer multiparameter outputs for flow and temperature, with a four-wire platinum RTD option. Note that PWM provides only raw pulse output signals, requiring additional signal processing for actual flow and temperature readings.

Catalog excerpts

PADDLE WHEEL FLOW METERS Flow meters for liquid flow applications. Jewel bearings allow for very low minimum flow rates. Easy to install and operate. Mounted horizontally or vertically. Only one moving part. Flow indication via transparent acrylic cover. Versatile square wave flow output signal. Female NPT ports. Multiparameter: flow and temperature *outputs. Four wires platinum RTD option. Polypropylene and chemically resistant PVDF models. * PWM provides only raw pulse output signals. In order to get actual flow and temperature readings, user has to implement additional signal processing. Fluid flowing through the unit causes the paddle wheel to spin. As the magnets embedded in the paddle spin past the sensor, electrical pulses are produced in which frequency is proportional to the flow rate. The number of pulses per desired time interval and the K-factor (number of pulses/gallon) make it is possible to calculate the flow rate and volume passing through the unit. TABLE 30 - FLOW RATE FOR PWM TABLE 32 - PADDLE WHEEL MODEL NUMBERS METER SIZES Inlet/Outlet Ports Female NPT Max Pressure Drop POLYPROPYLENE TABLE 33- WETTED MATERIALS OUTPUT SIGNAL NPN open collector (load 30 mA max). PADDLE WHEEL PVDF 56H x 108L x 53D [mm] (2.2 x 4.25 x 2.2") Without RTD and flow sensors. Nickel Tungsten Carbide Zirconia Ceramic Sapphire Jewels Sapphire Jewels Flow signal 1.8 m (6') or optional 3.7m (12') [ft.] RTD 12 [in.] long cable. Platinum 0.00385 TCR, meets EN 60751, Class B. POLYPROPYLENE MODELS PVDF UNITS MODELS 55 www.aalborg.com - e-mail ౧ [email protected] - ( 845.770.3000 - fax 845.770.3010 - Toll Free in U.S.A. and Canada 1.800.866.3837

Open the catalog to page 1

PWM Paddle Wheel Meter

PWM Paddle Wheel Meter

Catalog excerpts

All Aalborg Instruments catalogs and technical brochures