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  • Users: CostasV
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  1. CostasV

    Battery monitoring system with ATEX certified sensors ?

    Hello, We have a separate battery room for our [6 x 45 kW] UPS systems, housing around 250 VRLA lead-acid and NiCd batteries, with ATEX-certified lighting and ventilation. We want to install a battery monitoring system (BMS), with the main unit located in an adjacent, non-ATEX room. However...
  2. CostasV

    Screw terminal burnt

    Hi all, During an annually check we have found that inside an ESD marshalling cabinet, one of the two parallel PSU 230VAC/24VDC-40A was not working because the 230 VAC feeder screw terminals and cables (6 mm2) were burnt. The terminal plastic insulation melted, phase and neutral came to...
  3. CostasV

    Compressor vent gas injected to lower pressure network

    Hi, We have a compressor station where the process vent gas is 1000 normal m3 for each stop. This gas quantity is now released into the atmosphere. The total number of venting actions is about 20-60 per year. If we inject this quantity into a lower pressure network (city distribution network)...
  4. CostasV

    Discrepancy in the pressure

    Hi all, Could someone explain the discrepancy in the pressure, in the tag of photo? Is it possible to have a #600 valve, and the MOP to be 264 psi at 80 degC and 285 psi at -24 degC? https://res.cloudinary.com/engineering-com/image/upload/v1617037124/tips/valve_tag_pveaye.pdf...
  5. CostasV

    Pemex Reynosa September 2012 explosion

    Hi all, During a safety seminar the safety engineer presented the video of Pemex Reynosa September 2012 explosion. But without any further information. As I understand, in 0:32, the above ground pipe (or maybe a valve or metering unit ? ) is totally ruptured and then the pipe rotates, almost...
  6. CostasV

    Gas filter differential pressure

    We had a natural gas filter differential pressure reading that we can not explain. Maybe someone could help. The equipment is a filter OD 1320mm horizontal pressure vessel, design pressure 80 bar. It contains 37 cartridges D192mm X d90mm X 878mm. Design flow 500.000 Nm3/h at line pressure 40...
  7. CostasV

    Pylos combat agate - Miniature drawing

    Without magnifying glass, what other way is there to scribe this drawing on a 36 mm sealstone?
  8. CostasV

    Battery poles connencting strip repair

    We found that our second hand battery operated vehicle (made in 2001) had some heavily corroded connecting strips. Luckily the corroded part is in the middle of the strips, leaving the ends relatively in good condition. The corrosion is such that only the half of the cross section of the strip...
  9. CostasV

    Water level in NiCd batteries

    I never gave it much thought until a colleague of mine asked me why the water level increases. To refill water in a NiCd battery that has a low water level I have to unscrew the cap. Then gas is released to atmosphere. During this release, before I totally remove the cap, the water level seen...
  10. CostasV

    Pipeline failure (through hole) due to lightning

    According to the article "Pipeline Failure Results from Lightning Strike: Act of Mother Nature?" , a through hole in a 4.8 mm wall thickness, underground pipe, can be attributed to lightning strike. Is it only me who finds this explanation groundless? If a lightning hits a metallic object, it...
  11. CostasV

    Black sticky mud from diesel tank bottom

    A few weeks ago, we found that in the bottom of the backup diesel generator diesel tank (5000 lit), there was about 2cm of dark brown (almost black) sticky sediment, with viscosity like toothpaste, maybe even thicker. The diesel was inside the tank for about 4 years, no new fuel added. It had...
  12. CostasV

    Pyrami

    Having read this http://cse.fraunhofer.org/Default.aspx?app=LeadgenDownload&shortpath=docs%2FEUPVSEC_2010_Light_Transmission.pdf I understand that there are two ways that increase the yield of the solar module: the increased light transmission and the decreased temperature of the cell...
  13. CostasV

    Pressure adjustment in city distribution network

    In a typical city distribution network, the pressure is kept almost constant at the pressure set point, lets say at 8 bar(g). I have recently heard that if the pressure set point is adjusted (and thus the pressure in the network), for example it is increased to 12 bar(g), or decreased to 6...
  14. CostasV

    Gas temperature increase during filling

    I am trying to explain (or even better to find a relationship describing) the gas temperature increase in the scraper-trap of a natural gas pipeline system, when it is filled with gas (from 0 bar to 50 bar) wich is supllied from a 50 bar underground (at steady temperature of aprox. 8 deg C)...
  15. CostasV

    Two cables' connection in explosive area

    This is not my area of expertise. I want to connect two cables of the same type in order to add two more meters to the already 20-25 meters of the existing one. This cable is used to supply 230 V AC to a motor, and it has 11 wires in it. The explosion protection is of the "Intrisicaly Safe"...
  16. CostasV

    Ancient Greece: science, technology, arts

    If you are interested in ancient greek technology you can search in http://www.mlahanas.de/Greeks/Greeks.htm Regards Costas
  17. CostasV

    Battery question: (254 X 1.5V) vs (32 X 12V)

    Hello, we have a UPS system that uses 254 batteries if 1.5V in order to give 380V DC. My question is why not 32 batteries of 12V. Thanks in advance Costas
  18. CostasV

    Grease as sealant in gas valves

    Good morning I am interested in the use of grease as sealant in high pressure (60 bar / 900 psi) gas valves with diameter 4” to 36” for transportation pipelines. We have been working with Cristensens PR lubricant No 711 and were able to reduce leaks in buried plug valves of 8”. I have read...
  19. CostasV

    To close or not to close?

    I work in the gas distribution and transmission for 7 years. I have learned that continuous supply to the customers is one of the major requirments of the job. In this sense, we always try to minimise any possibility of stopping the supply to the customer. As a result, for example, we avoid to...
  20. CostasV

    Access to a device at the ceiling

    Hello all, I am facing a problem and I think I can use some good advice. We have natural gas detectors installed at the ceiling of the building and not near the walls. The height of the ceiling varies from 6 to approx. 9 m. In order to have access to these detectors for periodic maintenance...

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