Sample Intake Screen Specification

  1. General
  2. : The intake screen shall be of all-welded, continuous slot profile wire construction to provide the maximum open area commensurate with the strength requirements as per section 3 below. The inlet slots shall widen inwardly from the screen surface so as to minimize the entrapment of debris in the screen openings. The design shall include low head loss flow field control.
  3. Capacity
  4. : The screen assembly capacity shall be 999 litres per second at a maximum approach velocity of 0.114 metres per second for subcarangiform fish protection or 0.038 metres per second for anguilliform fish protection. At this flow rate the pressure drop through the clean screen surface shall not exceed 0.7 kilopascals (0.1 psi). Pressure drop through the screen assembly shall be in the range of 0.75 kilopascals (0.11 psi) at rated flow.
  5. Strength
  6. : The screen shall withstand a differential hydrostatic collapse pressure in excess of 30 kilopascals. Maximum allowable design stress when determining strength shall be 1476 kilograms per square centimetre. Strength calculations verifying compliance with these criteria shall be provided upon request.
  7. Construction
  8. : The surface wire shall be profile wire of 1.8mm head width with a 5-10 relief angle for slots less than 635mm and profile wire of minimum 3mm head width with an 5-10 relief angle for slots of 6.35mm and larger. The surface wire, support rod, and stiffener structure shall be of all-welded construction designed to provide the specified strength with minimal interference with the through-screen flow pattern. All structural butt welds shall be full penetration; structural fillet weld size shall be the thickness of the thinner component. An internal flow field modulator shall distribute flow evenly across the entire screen area.
  9. Slot
  10. : The screen slot size shall be 2.54 mm. The open area for this slot opening shall be 58.5%. Slot size shall be controlled and continuously monitored during manufacture. No slot opening in the assembly shall exceed the designed slot opening by more than 0.15mm.
  11. Materials and Fittings
  12. : The screen assembly shall be manufactured of type 304 stainless steel throughout. The outlet flange shall mate with a 999 NB flange with a flange bolt pattern equal to ANSI Class 150.