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Locking Band | Internal Door Closures

S-3000 Locking Band | Internal Door Quick Opening Closures

The S-3000 is Stark’s Internal Door design which is manufactured in diameters ranging from 6” to 84” (DN150 to DN2100). The closure design concept relies on the proven method of a locking ring that slides into the closures outer hub. When expanded to the closed position, the locking ring assembly securely latches the door into place. Durable components are used to actuate the locking ring and are designed to withstand the demands of long-term operation.


  • Broad Size Range and Pressure Series 
  • O-Ring design with large cross section on horizontal and vertical closures, for 
  • positive seal, protection from light wear and corrosion, and cost efficiency
  • Lip seal design on horizontal and vertical closures 
  • Improved operation with load binder assist on horizontal sizes 24” (DN600) 
  • and larger 
  • Fail- safe Design

  • Internal Door Closure S 3000 1

    Internal Door Closure S 3000 1

  • Internal Door Closure S 3000 2

    Internal Door Closure S 3000 2

  • Internal Door Closure S 3000 3

    Internal Door Closure S 3000 3



  • Certified to ASME B31.3/B31.4/B31.8/CSA Z662 Cat. I / ASME SEC VIII DIV. 1
  • Pressure Alert Valve per UG-35.2 of ASME BPVC VIII DIV. 1 
  • Nace MR0175 compliant material 
  • -50° to + 400°F (-45° to 204°C) 
  • Viton O-Ring supplied with closure 


  • Flanged Closure – welded connection or one piece
  • ASME BPVC VIII DIV. 1 with U-Stamp for door only or whole closure (hub, 
  • door, locking ring) 
  • Stainless Steel, duplex, super-duplex
  • Inconel or Stainless-Steel weld overlay 
  • External hinge trim for Offshore uses 
  • Hydraulic lift on vertical closures
  • Special materials and O-Rings 
  • Horizontal or Vertical orientation