Explosion proof pressure transmitter Shanghai Automation Instrument Factory 1151 intelligent pressure transmitter with Hart pressure transmitter

1、 Instrument Overview:

Explosion proof pressure transmitterIt is a new type of transmitter produced by introducing advanced foreign technology and equipment. The key raw materials, components, and parts are all imported. The entire machine has undergone strict assembly and testing. This product has the characteristics of advanced design principles, complete varieties and specifications, and easy installation and use. Due to the complete integration of the structural advantages of the two widely used transmitters (Rosemount 3051 and Yokogawa EJA), which are currently popular in China, this model provides users with a refreshing feeling. At the same time, it can be directly replaced with traditional series products during installation, with strong universality and substitutability.

2、 Measurement principle:

Explosion proof pressure transmitterThe principle is to form a capacitor by measuring the diaphragm and the electrodes on both sides of the insulation sheet. When the pressure on both sides is not equal, it causes displacement of the measuring diaphragm. The displacement is proportional to the pressure difference, so the capacitance on both sides is not equal. Through oscillation and demodulation, it is converted into a signal proportional to the pressure, and then through temperature compensation and linear correction, it is converted into a standard electrical signal.

3、 Applicable occasions:

The main structure of the diaphragm pressure transmitter is the same as that of the pressure transmitter. In order to adapt to different installation needs, this series of transmitters has various forms of remote transmission devices for users to choose from. This product is widely used in industries such as petroleum, chemical, power, food, papermaking, and municipal engineering.

1. Viscous medium at high temperature;

2. A medium that is easy to crystallize;

3. Sedimentary media with solid particles or suspended solids;

4. Highly corrosive or highly toxic media;

It can eliminate the occurrence of pressure pipe leakage polluting the surrounding environment; It can avoid the tedious work of frequently supplementing the isolation liquid due to the unstable measurement signal when using isolation liquid.

5. Continuous measurement of interface and density;

The remote transmission device can avoid the mixing of different instantaneous media, so that the measurement results truly reflect the actual situation of process changes.

6. Places with high hygiene and cleanliness requirements;

In the production of food, beverage, and pharmaceutical industries, it is not only required that the contact area of the transmitter with the medium comply with hygiene standards, but also be easy to rinse to prevent cross contamination of different batches of media.

4、 Performance characteristics:

1. The indication is novel, the reading is intuitive, eye-catching, and the direction of the observation indicator can be changed according to the user's needs.

2. Simple structure: Without any movable or elastic components, it has high reliability and minimal maintenance.

3. Easy installation: The built-in structure particularly demonstrates this feature, without the need for any tools.

4. Convenient adjustment: the zero and range Potentiometer can move the zero or change the range at will within the effective range of liquid level detection, and the two adjustments will not affect each other.

5. Widely used; Suitable for liquid level measurement in media such as high temperature, high pressure, and strong corrosion.

6. The measurement range is large and not limited by the height of the storage tank.

7. The indicating mechanism is completely isolated from the tested medium, with good sealing performance, high reliability, and safe use.

8. Equipped with intrinsic safety explosion-proof and isolation explosion-proof capabilities, it can be applied to various hazardous locations.

9. Equipped with anti blocking design, it can measure the liquid level of paste media.

10. Fine and unique zero point, full range, and nonlinear compensation ensure the accuracy of the instrument within the range of operating conditions, and good long-term stability.

5、 Technical indicators:

1. Output signal: 4-20mA DC two wire system (analog) Two wire system 4~20mA DC signal superimposed with a digital signal, with linear or square output selected by the user. (Intelligent)

2. Power supply: 12-45V.DC.

3. Load characteristics:

Power supply impact:<0.005% output range/V;

Load impact: When the power supply is stable, there is no load impact;

Measurement accuracy: ± 0.1% of the calibrated range, with a standard accuracy of ± 0.2%. If other accuracies are selected, please indicate them when ordering and selecting;

Range ratio: 10:1 or 100 to 1;

Damping: Usually adjustable between 0.1 to 16 seconds, the time constant will increase when inert liquid is filled or with a remote transmission device;

Start time:<2 seconds, no preheating required.

4. Working environment: ambient temperature -29~93 ℃ (analog amplifier);

-29~75 ℃ (digital/intelligent amplifier);

-29~65 ℃ (with display head);

The ambient humidity is 0-95%.

5. Protection characteristics: Protection ability IP65;

6. Explosion proof type: Explosion proof Exd II BT4-6;

Intrinsically safe Exia II CT5.

7. Static pressure effect: Zero position error: ± 0.5%. Large range limit value, corrected by zero adjustment under pipeline pressure of 32MPa.

8. Electromagnetic radiation impact: 0.05% of the range value, with a radiation frequency of 27-500MHz and a test field strength of 3V/m.

9. Indicator (%): LCD digital display accuracy ± 0.2%.

10. Vibration impact: ± 0.05%/g when vibrating at 200Hz in any direction.

11. Installation position: The diaphragm is not installed vertically, which may result in a zero point error of less than 0.24KPa, but can be corrected by zero adjustment.

12. Weight: 3.9Kg (excluding accessories).

6、 Maintenance procedures:

1. Structural composition:

A single flange liquid level transmitter consists of a differential pressure transmitter, a capillary tube, and a flange with a sealing diaphragm. The function of a sealing diaphragm is to prevent the medium in the pipeline from directly entering the differential pressure transmitter. It is connected to the transmitter by a capillary filled with liquid (usually silicone oil). When the diaphragm is compressed, it undergoes small deformation, displacement or frequency, which is transmitted to the transmitter through the liquid in the capillary. After processing by the transmitter, it is converted into an output signal.

2. Appearance inspection:

a. Flange inspection: Check whether the sealing between the flange and the equipment connection is good; Check if there is any liquid leakage between the flange and the capillary, the connection between the capillary and the transmitter, and the capillary itself; Check if the flange diaphragm has any deformation, damage, corrosion, scaling or other adverse conditions.

b. Transmitter inspection: Check the transmitter casing for damage, corrosion, and other faults, and promptly handle any problems found.

3. Acceptance:

a. Open the outer cover of the transmitter and first check if the sealing ring is damaged. If it is damaged, replace it in a timely manner; Check if the circuit board and other components are in good condition.

b. Check if the transmitter wiring is in good condition.

c. Disconnect the power supply, remove the wiring, conduct insulation resistance inspection, and use a 500V megohmmeter to check the insulation resistance between the transmitter terminal and the casing. The resistance value should be greater than 20M.

4. Debugging and calibration of single flange liquid level transmitter

In order to ensure the measurement accuracy of the single flange liquid level transmitter, the capillary tube cannot be disassembled, so when calibrating the transmitter, it should be calibrated together with the flange; Before installation, a pneumatic analog signal can be used to verify with a HART communicator.

b. Zero and span adjustment steps: Adjust the zero and span outputs to within the allowable error range. Continuous pressurization, use the pressure of 0%, 25%, 50%, 75% and 150% of the measuring range for calibration. When the pressure is stable, record the current value displayed on the standard Ammeter and perform the return error calibration. If the calibration error exceeds the allowable error range, the calibration should be readjusted. When adjusting, use HART operation, and the adjustment method can be found in the corresponding HART instructions.

4. Installation:

a. Installation of remote transmission flange:

The flanges on both high and low pressure sides should be installed correctly and cannot be reversed; To reduce the impact of environmental temperature difference, the capillaries on the high and low pressure sides can be bunched together and fixed to prevent the influence of wind and vibration (the capillaries on the ultra long part should be rolled together and fixed); Be careful not to damage the surface of the liquid receiving diaphragm. Do not twist or squeeze the capillary tube, nor apply excessive pressure to it.

b. Installation of the transmitter body: Use a mounting bracket to install the transmitter body on a pipeline with a diameter of 50mm. Horizontal and vertical piping installation can be carried out.

5. Precautions:

a. Tighten the four bolts of the measuring chamber, and the fixing screws connecting the capillary tube and the chamber part must not be loose to prevent leakage of the sealing liquid and damage to the instrument.

b. When wiring, interference sources such as large capacity transformers, motors, or power supplies should be avoided; When wiring, the dust plug of the power interface should be removed; The threaded part should undergo waterproofing treatment (non hardening silicone resin series sealant should be used during waterproofing treatment); To prevent interference, signal cables should avoid penetrating the same cable protection tube as other power cables; For explosion-proof instruments, to ensure explosion-proof performance, wiring must be carried out in accordance with relevant regulations.

8、 Application process precautions:

1. When measuring liquid pressure, the installation position of the flange level transmitter should avoid liquid impact (i.e. water hammer phenomenon) to avoid damage to the sensor due to overpressure.

2. When a single flange liquid level transmitter freezes in winter, anti freezing measures must be taken for the transmitter installed outdoors to prevent the liquid in the pressure inlet from expanding due to freezing volume, which may cause damage to the sensor.

3. When wiring, thread the cable through the waterproof joint (accessory) or flexible tube and tighten the sealing nut to prevent rainwater and other leakage into the transmitter housing through the cable.

4. When measuring liquid pressure, the pressure tap should be opened on the side of the process pipeline to avoid sediment accumulation.

5. To prevent the flange liquid transmitter from coming into contact with corrosive or overheated media, and also to prevent sediment from depositing in the conduit;

6. When measuring the pressure of gas, the pressure tap should be located at the top of the process pipeline, and the flange level transmitter should also be installed at the top of the process pipeline to quickly inject the deposited liquid into the process pipeline.

7. Pay attention to installing the pressure pipe of the sensor in a place with low temperature fluctuations;

8. When measuring steam or other high-temperature media, it is necessary to connect a condenser such as a buffer tube (coil), and the working temperature of the transmitter should not exceed the limit.