MAXREFDES70#: High Accuracy, Long Battery Life Heat/Flow Meter

Overview

Accuracy, cost-effective, ultrasonic flowmeter brings a key change to liquid and gas flow measurement. Flow meters are critical for bill collection, leak detection and the protection of critical natural resources. They are core equipment in utility and industrial distribution systems such as water, gas and heat. The most widely used mechanical flow meters today use moving parts to measure the velocity of liquids in pipes. These moving parts are prone to wear and tear over time, reducing accuracy, and often require replacement within 10 years. Maxim Integrated's MAXREFDES70# ultrasonic transit time flow meter sends and receives signals between piezoelectric sensors in both the upstream and downstream directions of the pipe. By measuring the TOF difference between uplink and downlink ultrasonic transmission, and using mature digital signal processing technology, a flow value with very high accuracy can be calculated.

The MAX35101 is the heart of a heat/flow meter system. The MAX35101 integrates all the functions required for automatic TOF measurements, including ultrasonic pulse emission and detection, TOF calculation, temperature measurement, and real-time clock (RTC) . The MAX35101 can operate in a configurable automatic event timing mode that requires minimal host microcontroller intervention, thereby reducing overall system power consumption.

The MAXREFDES70# reference design (Figure 1) demonstrates a typical application of the MAX35101 TOF converter. Please note that the flow meter is not calibrated and is intended only as a high performance platform for developing custom heat/flow meters. For details on calibration, please contact the manufacturer. 

System Block Diagram

Figure 1. MAXREFDES70# reference design block diagram.

characteristic

• High precision

• Large range

• Ultra-low power consumption (battery life of 20 years)

• Compact structure and low cost

application

• Ultrasonic heat meter

• Ultrasonic air conditioner meter

• Ultrasonic water meter