The BTU meter is consisted of an ultrasonic flow sensor, a pair of PT1000 temperature sensors and a calculator (integrator). The microprocessor-based calculator controls the ultrasonic sensor to transmit and receive ultrasound in an orderly fashion so as to conduct precise flow measurement. It also has electronics dedicated to the PT1000 sensor to measure the temperature in the supply pipe as well as the return pipe. The calculator calculates the thermal energy based on the flow rate and the differential temperature between the supply and the return water. The figures below illustrate how the ultrasonic flow sensor works. Two ultrasonic transducers (A and B) are mounted on the flow cell body of the flow sensor, one is on the upstream and the other on the downstream. Two reflectors are used to direct the sound from one sensor to another. The integrator operates by alternately transmitting and receiving a burst of sound energy between the two transducers and measuring the transit-time it takes for sound to travel between the two transducers. The difference in the transit-time measured corresponds directly to the velocity of the liquid in the pipe.
Nominal Diameter | 15 | 20 | 25 | 32 | 40 | |
Dimension | L(mm) | 110 | 130 | 130 | 180 | 200 |
W(mm) | 85 | 85 | 85 | 85 | 85 | |
H(mm) | 105 | 105 | 115 | 125 | 130 | |
Max flow (m3/h) | 3 | 5 | 7 | 12 | 20 | |
Norm flow(m3/h) | 1.5 | 2.5 | 3.5 | 6 | 10 | |
Min flow(m3/h) | 0.03 | 0.05 | 0.07 | 0.12 | 0.2 | |
Power supply | 3.6VDC | |||||
Battery life | >6 years ( Lithium battery) | |||||
Accuracy class | Class 2 | |||||
Communication mode | M-BUS/RS485 Infrared interface | |||||
Working pressure | ≤ 1.6 Mpa | |||||
IP class | IP 68 | |||||
Temperature range | (4--95) ℃ | |||||
Temperature difference range | (3--70) k | |||||
Temperature sensor length | 1.5m | |||||
Data storage | Can store the past 24 months of historical data | |||||