digital water propane flow meter

digital propane flow meter

Product overview of propane flowmeter
Vortex flowmeters are widely used in petroleum, chemical, metallurgical, thermal, textile, paper and other industries for superheated steam, saturated steam, compressed air and general gases (oxygen, nitrogen, hydrogen, natural gas, coal gas, etc.), water and liquids (such as: Water, gasoline, alcohol, benzene, etc.) measurement and control.
Flange standards: GB/T9119-2000 and GB/T9113.2-2000 flange standards and materials can also be determined according to the specific requirements of customers. Body material: 304 stainless steel. Detection sensor material: 316L.
Liquid crystal display: The flow meter is equipped with a high-precision liquid crystal display, double-row liquid crystal, 8-digit digital display, which can display the cumulative flow, the eye-shun time flow, the flow rate, the communication address and the large flow corresponding to the output 20mA (can be set arbitrarily ) And flow direction indication. Mileage ratio: 20:1.
The working principle of propane flowmeter
If a non-streamline vortex generator (bluff body) is installed in the fluid, two rows of regular vortices are alternately generated from both sides of the vortex generator. This type of vortex is called the Karman vortex street.
The vortex array is arranged asymmetrically downstream of the vortex generator. Suppose the frequency of the vortex is f, the average velocity of the measured medium's incoming flow is V, the width of the front face of the vortex generator is d, and the diameter of the surface body is D. According to the Karman vortex street principle, the relationship is as follows:
f=StV/d formula (1)
Where:
f－Carman vortex frequency generated on one side of the generator
St-Strohal number (dimensionless number)
V－The average flow velocity of the fluid
d-the width of the vortex generator
It can be seen that the instantaneous flow can be calculated by measuring the separation frequency of the Karman vortex street. Among them, the Stroghal number (St) is a dimensionless unknown number,
The figure shows the relationship between St Rohal number (St) and Reynolds number (Re).
In the straight part of the curve table with St=0.17, the release frequency of the vortex is proportional to the flow velocity, which is the measurement range of the vortex flow sensor. As long as the frequency f is detected, the flow velocity of the fluid in the tube can be obtained, and the volume flow rate can be obtained from the flow velocity V. The ratio of the measured pulse number to the volume is called the meter constant (K), see formula (2)
K = N/Q (1/m3) Formula (2)
In the formula: K = instrument constant (1/m3).
N = number of pulses
Q=Volume flow rate (m3)
Product features of propane flowmeter
1. The installation is simple and the maintenance is very convenient;
2. The structure is simple and firm, without moving parts, and it is very reliable for long-term operation;
3. Wide measuring range, the measuring range ratio can reach 1:15;
4. Small pressure loss, low operating cost, and more energy-saving significance;
5. Wide application range, liquid, gas and steam can be measured;
6. The verification cycle is long, generally two years;
7. Within a certain Reynolds number range, the output signal is not affected by changes in the physical properties and composition of the measured medium. The meter coefficients are only related to the shape and size of the vortex generator. Generally, there is no need to recalibrate the meter coefficients after changing accessories;
8. It can be displayed on site, can also be transmitted over a long distance, and can also be networked with a computer control system;
9. The detection probe does not directly touch the measured medium, and the performance is more stable.
The pressure loss is small, the measuring range is large, and the accuracy is high. When measuring the volume flow of the working condition, it is almost not affected by the fluid density, pressure, temperature, viscosity and other parameters. There are no movable mechanical parts, so the reliability is high and the maintenance is small. Using piezoelectric stress sensor, the instrument parameters can be stable for a long time, and it can work in the working temperature range of -20℃～+250℃. There are analog standard signals and digital pulse signal output, which is easy to use with digital systems such as computers. It is a relatively advanced and ideal flow meter
Main technical indicators of propane flowmeter
Nominal diameter (mm): 25, 40, 50, 65, 80, 100, 125, 150, 200, 250, 300, (300～1000 plug-in type)
Nominal pressure (MPa): DN25-DN200 4.0 (>4.0 agreement supply), DN250-DN300 1.6 (>1.6 agreement supply)
Medium temperature (℃): Piezoelectric type: -40～260, -40～320; Capacitive type: -40～300, -40～400, -40～450 (Order by agreement)
Body material: 1Cr18Ni9Ti, (other materials supplied by agreement)
Allowable vibration acceleration: piezoelectric type: 0.2g, capacitive type: 1.0～2.0g
Accuracy: ±1%R, ±1.5%R, ±1FS; plug-in: ±2.5%R, ±2.5%FS
Range: 1:6～1:30
Supply voltage: sensor: +12V DC, +24V DC; transmitter: +12V DC, +24V DC; battery-powered type: 3.6V battery
Output signal: square wave pulse (not including battery-powered type): high level≥5V, low level≤1V; current: 4～20mA
Pressure loss coefficient: in line with JB/T9249 standard 　Cd≤2.4
Explosion-proof mark: Intrinsically safe type: ExdⅡia CT2-CT5 Explosion-proof type: ExdⅡCT2-CT5
Protection level: common type IP65, submersible type IP68
Environmental conditions: temperature -20℃～55℃, relative humidity 5%～90%, atmospheric pressure 86～106kPa
Applicable medium: gas, liquid, steam
Transmission distance: three-wire pulse output type: ≤300m, two-wire standard current output type (4～20mA): load resistance ≤750Ω