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  • Users: BRIS
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  1. BRIS

    Do we need accumulators on compress

    Do we need accumulators on compressors serving surge vessels. I assume without accumulators we will have a lot of banging around in the air line and it will be difficult to control the air injection ?
  2. BRIS

    Standard Construction Specifications

    We have a project in the Middle East preparing design and specifications - the client has requested that the technical specifications are to be as published by CSI (construction Specification Institute. As far as we are aware the CSI provides a numbering system only - do the CSI publish...
  3. BRIS

    Disinfection CLO2 electrical power demand

    The client wishes to change from CL to CLO2 to be manufactured on site from sodium Chlorite and HCL. water is desalinated water at 48 degree C volume is 50 Million gallons per day - dosing at 2 ppm, I am trying to prepare a budget estimate for the supporting infrastructure works. Question is...
  4. BRIS

    Pump System Curve Symantics

    We have a complex distribution system which is expected to experience a demand growth of some 50% over the next 10 years. The system has several sources of supply all from desalination plants which pump directly into the system through ground storage tanks. There are also a number of evaluated...
  5. BRIS

    VFD Voltage

    We have a design with 12 motors each 3.3 kV (power ratings from 300 Kw to 1000 Kw) 9 motors have VSD drives the other 3 have soft start. Incoming power supply is 11 kV. My question is why do we not transform the incoming supply to 3.3 kV instead of having one 3.3 kV transformer on each drive (12...
  6. BRIS

    Oversizing pumps and motors

    In the old days we often used to oversize water supply pumps - and then ended up adding orifice plates to bring them onto their duty curve - over the past 20 years I have instead evaluated worst case hydraulic scenarios (maximum and minimum) and ensured that the selected pumps best meet the duty...
  7. BRIS

    VFD Reliability

    I have inherited a water pump station design that has adopted two duty one stand-by pump sets. The pumps each rated at 1.8 MW are designed with VSD drive. The pumps are a sole source of supply to a distribution zone of a major city. The station must operate 24/7, Reliability is paramount for...
  8. BRIS

    VSD Reliability - We have 2 duty 1

    VSD Reliability - We have 2 duty 1 stand-by pumps supplying direct into water supply distribution each pump rated at 1800 kW. We have proposed 3.3 kV - VSD drives. The system must have continuous operation and near 100% reliability. The client is concerned over the reliability of the VSD drives...
  9. BRIS

    Hec-ras weir coefficients

    I have received results of hec-ras river modelling showing impacts of adding 1.0m high weirs designed to improve aeration in a river. I am surprised to find that the provision of a 1.0m high weir with a length equal to the full width of the river has created a 1.0m rise in water level. The...
  10. BRIS

    Comparison of ASTM D1693 and D 5397 NCTL ESCR

    We have a specification for HDPE which calls for the material to meet 10,000 hours when tested in accordance with ASTM D1693 F50 The material has been tested to ASTM 5397 NCTL at 50 degree c and failed after 200 to 600 hours. Is there any way that I can correlate the different tests?
  11. BRIS

    EPDM Valve Seals - Water service - Chlorine Dioxide

    We have recently changed from water disinfection by chlorine gas to chlorine dioxide. Previously specified seals and gaskets to be manufactured from EPDM. It has been suggested by one manufacturer that EPDM is no longer suitable for use with chlorine dioxide disinfectant and that we should...
  12. BRIS

    Butterfly Valve Bi-directional valve installation

    We have a twin 1600mm ductile iron water pipeline that can flow in either direction. Pressure is 11 bar. The pipeline is 100 km long with butterfly isolation valves at 5km intervals The butterfly valves are installed on flanged spigots cast into the valve chamber wall with a flange adaptor on...
  13. BRIS

    Switching VFD

    We have a potable water pumping station which will be equipped with 13 identical pumps. For the majority of the time only 3 of the pumps operate. The remaining pumps are for emergency transfer of water. The 3 pumps used in normal operation are required to meet variable flow conditions and will...
  14. BRIS

    World's largest service Reservoirs

    We have a client in the ME who want's to build the World's largest potable water service reservoirs; each 100 million gallon capacity. He want's to know what are the largest service reservoirs built anywhere in the world to date ?
  15. BRIS

    Motor starting frequency

    What is the meaning of the following in relation to pump starting: Motors shall withstand at least:  3 consecutive starts, at 80% Un, with load inertia according to IEC60034-12.
  16. BRIS

    Large Deep potable water service Reservoirs

    I am looking at options for large covered potable water storage reservoir. Apart from the standard rectangular RC and circular pre stressed options, I am considering the possibility of secant pile or diaphragme walls. I am searching for examples of where they may have been used before.
  17. BRIS

    Cable Support Systems IEC 61537 v Nema VE 1

    Our specification calls for cable support systems to IEC 61537. The Contractor is proposing systems to NEMA VE 1. Are these two standards equivalent?
  18. BRIS

    B31.4 Elastic Bend Stress Allowance

    We are laying a buried 72' diameter CS grade x65 with 15.48 mm wall thickness with Cement Mortar Lining for water supply. Contractor proposes to pull elastic bends to follow the horizontal alignment. I am not familiar with B31.4. Does the standard permit the use f elastic bends, is there any...
  19. BRIS

    CP for steel pipe in Steel casing

    We have a 72in diameter buried CS welded steel pipe with CP protection. Specification called for road crossings by thrust boring with an 80 inch ID concrete casing. Steel line pipe was to pass through casing with annulus between the pipe and casing grouted with cement grout. Contractor has...
  20. BRIS

    Air cooled v Water Cooled Motor

    we have 2.5 MW pumps (13.8 Kv) that have been specified with air cooled motors. The client has now instructed that the motors shall be water cooled. This is a desert environment - air temperature 25 to 50 degree C, water temp 25 to 60 degree C. I would be interested to know what the pros and...

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