Zhongyi Smart's Self-Developed Ultrasonic Metering Module

Zhongyi Smart's self-developed ultrasonic flow measurement module (referred to as the flow channel) employs the ultrasonic time-of-flight method to measure gas flow. The ultrasonic time-of-flight method utilizes the principle that the time difference between ultrasonic waves traveling in the same direction and opposite direction within the gas medium is proportional to the average gas flow velocity. By calculating the relationship between the ultrasonic propagation time difference and distance, the gas flow velocity is determined. The gas flow rate is then obtained by multiplying the flow velocity by the cross-sectional area of the gas meter pipeline.

1. Relationship Between Propagation Time and Flow Velocity

The propagation times for ultrasonic waves traveling with and against the flow in gas are respectively:

where:

tdown: Ultrasonic wave propagation time with flow (s)

tup: Ultrasonic wave propagation time against flow (s)

L: Channel length (m)

cf: Sound propagation velocity in gas (m/s)

vm: Average gas velocity (m/s)

ϕ: Channel angle (°)

The average gas velocity can be derived from (1) and (2):

vm = 2cosϕL (tdown1 − tup1) (3)

2. Instantaneous Flow Rate Calculation

The instantaneous flow rate can be obtained based on the average gas velocity vm and the channel cross-sectional area S:

q = 3600 × vm × S (4)

Where:

S: Channel cross-sectional area (m²)

q: Instantaneous flow rate (m³/h)

Core Advantages

Non-contact measurement: No moving parts, minimal pressure loss, high reliability.

Wide turndown ratio: Covers flow ranges from minute to substantial.

High precision: Nanosecond-level time measurement accuracy ensures precise velocity and flow rate calculations.

Strong adaptability: Suitable for gas media with varying compositions, pressures, and temperatures.

Configure a prepaid accessory device—an electric motor valve—on the base meter. During meter operation, corresponding communication signals are transmitted to the controller, enabling the LCD electronic counter to display gas measurements. When gas consumption reaches (or is about to reach) the preset remaining allowance, the controller closes the motor valve and displays a warning message on the LCD. After purchasing gas through a recharge, users can operate the meter button to open the motor valve, restoring gas supply for continued use.