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| 7/24/2008 7:54 AM | |
Joined: 6/10/2008 Last visit: 10/28/2024 Posts: 193 Rating:
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Hello to all, I'm haveing a hard time fully understanding how to perform "zero check" with Sitrans P DS III differential pressure transmitter which measures water flow.I have found manual and part which is interesting to me is in attachment. However, this is rather complicated procedure and it is aimed for first time installation. Furthermore, there are some mistakes, for example step 8 says "close the active pressure valve(2)", while valve 2 is compensationvalve. Basically I have impulse pipes as shown in second picture "Transmitter below active pressure taps". I have orifice plate in pipe that have connections that leads to two transmitters. Both transmitters are calibrated in the same way, but there is significant difference in deltaP. Now I want to check zeros for both transmitters andsolve this problem. Since this measure water flow, I thought toperform following procedure: 1. Shut off both active pressure valves aswell as comp. valve remains closed(3A, 3B and 2) 2. Open slightly 7A and 7B (blowout valves) to make sure there is no air in the water. 3. Close blowout valves (7A and 7 B) 4. Open active pressure pressure valves 3A and 3 B 5. Open comp valve 2 in order to make equal pressure on both - and + chamber. 6. Correct zero with tranmitters calibration step (7 in operation instructions) 7. Shut off comp valve 2. Is this procedure correct, or I need to make this different? There is one alternative: 1. Shut off both active pressure valves aswell as comp. valve remains closed(3A, 3B and 2) 2. Open 7A slightly until sure that only water and no air is present, then shut off 7A 3. Open 7B slightly until sure that only water and no air is present 4. While 7 B is opened, open 3A, 2 and 3B so higher pressure will remove air if existsfrom + impulse pipe through 3B and lower impulse pipe. 5. Close 7B and 2 AttachmentValve manipulation.pdf (481 Downloads) |
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