Flange level transmitter
First, the product introduction
The level transmitter is a field transmitter that is mounted directly on the vessel or pipe. The isolating diaphragm is in direct contact with the liquid medium, and the positive pressure side conduit is not required to be taken out, so the liquid level, pressure and density of the medium such as high temperature, high viscosity, easy crystallization, easy precipitation and strong corrosion can be measured and then converted into 4-20mA·DC signal output.
The liquid level transmitter has ST type hygienic liquid level transmitter and LT type flange type liquid level transmitter. Combined with intelligent magnifying plate, it is intelligent liquid level transmitter and co-operator (according to HART). Protocol) can be used for communication, setting and monitoring.
The LT-type liquid level transmitters are mounted according to standard flanges; the ST-type sanitary level transmitters are quick-coupled using clamps. After the surface in contact with the medium is processed and treated, the finish and cleanliness meet the hygienic standard, and the filling liquid is selected and injected with the non-contaminating medium as a standard, so it is widely used in the pharmaceutical, beverage and food industries. department.
Second, the working principle
Capacitive pressure and differential pressure transmitters are mainly composed of chamber-sensitive components that implement pressure/capacitance conversion and convert the capacitor into a two-wire 4-20 mA DC electronic circuit board. (See the figure below)
When the process pressure is applied to the isolating diaphragm from both sides (or one side) of the measuring chamber, it is transferred to the central diaphragm of the & chamber through the silicone oil filling solution, and the central diaphragm is an edge-tensioned diaphragm. Under the action of pressure, a corresponding displacement (up to about 0.1 mm) is generated, which forms a differential capacitance change, and is converted into a two-wire 4-20 mA·DC signal output through adjustment, vibration and amplification of the electronic circuit board. The output current is proportional to the process pressure.
Third, the installation diagram
Fourth, technical parameters and performance
1, the output signal: 4-20mA · DC two-wire system;
2, power supply; 12-45V · DC;
3, power supply impact: <0.05%>0.05%>
4, load impact: when the power supply voltage is stable, no load impact;
5. Migration characteristics: the maximum positive migration amount is 500%, and the minimum negative migration amount is 600%;
● The absolute value of the negative migration is not more than one engineering atmospheric pressure;
● The absolute values of the upper and lower limits after migration should not exceed the upper limit of the maximum measurement range;
● Migration of differential pressure flow transmitter will destroy the square root characteristics, so migration cannot be performed;
● Absolute pressure transmitters cannot perform negative migration;
6, damping: usually adjustable between 0.2 ~ 1.67 seconds, when filling the inert liquid or with a remote transmission device, the time constant will increase;
7, start-up time: <2 seconds,="" no="" need="" to="">2>
8, explosion-proof type: explosion-proof ExdIIBT4-6 intrinsically safe type ExiaII CT5;
9, indicator table (%); ammeter, scale length 44.5mm, accuracy ± 2%, liquid crystal display, accuracy ± 0.2%;
10. Vibration effect: ±0.005%/g when vibrating in 200HZ in any direction;
11, installation position: the diaphragm is not installed vertically, can produce less than 0.24KPa;
12, temperature effect: ± 0.2%;
13. Static pressure effect: ±0.5%;
14. Accuracy: 0.25%, 0.5%, 1.0%
15, weight: 5.4Kg (excluding accessories);
Five, capacitive differential pressure transmitter selection