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Assembly Process of 3151 Differential Pressure/Pressure Transmitter

Apr 24, 2019



      The 3151 differential pressure/pressure transmitter is equipped with two parts: sensor assembly and electronic assembly.


1. Sensor installation


      Read the task order model and requirements carefully, and check if the parts are correct according to the model.



      1.1. DP. HP (GP negative pressure type) uses two common methods. GP. AP pressure uses a one-piece blind flange and a common flange.


      1.2. Check the capacitance of the sensor's capacitance on the high and low voltage sides within the specified range, and check the sensor's capacitance symmetry and capacitance loss value parameters, see Process.


      1.3. Check the appearance of the flange and whether there are trachoma holes in the machined surface. Loose and other defects; whether to do bumps, scratches, corner defects, under-casting and other casting defects: the same batch of flange color contrast, can not see the big difference with the naked eye.


      1.4. Check the 1/4-18 NPT thread and check the 4 M10 threads on the 2 sides, in good condition. Put in the fixture and carry out the assembly operation, please refer to the process. Remove the parts from the fixture when finished. Note: Confirm that the torque wrench should be tightened diagonally.


     1.5. Check whether the model and the assembly match. Place the sensor on the horizontal surface, and shake the sensor with the hand to be stable, requiring no obvious shaking.


      1.6. Fatigue the assembled sensor and eliminate the aging stress.



2. Housing and circuit board installation:


      2.1. Five output lines of the sensor, red (H), black (L), white (G), yellow (T+) gray (T-). After adjusting the length of the output line, peel off the wire and tin the wire. In the corresponding line and the excitation plate welding, it is required to weld to the specified position, the welding is firm, and the hand is gently pulled to check whether it is rich. Secure the excitation plate to the sensor.


     2.2. Check the internal thread of 3151 bright body neck, whether it is stained with processed aluminum chips and castings, the external thread of the sensor neck is smooth, and the external thread of the sensor neck is coated with silicone grease.


      2.3. Check the feedthrough capacitance of the connector housing. The upper end is 24 positive and the lower end is 24 negative welding power supply line.


     2.4. Carefully thread the cable on the sensor into the screw hole of the electronic housing mounting sensor, and screw the sensor into the left and right of the electronic housing 8 so that the high-voltage chamber of the sensor is on the same side as the display head of the electronic housing. Note that the sensor cannot be twisted when it is screwed into the electron beam. Connect the cable to the electronic board and fix it on the positioning post with M3 screws. S.Z is on the lower side and M is on the upper side.


      Pay special attention to the height of the circuit board of the housing, the height of the mounting positioning post is different, and the three cover buttons cannot be squeezed by screwing the window cover. Install the exhaust pressure relief valve and the commissioning joint of the instrument to ensure that it will not leak.