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B400 PV Emergency Relief Manway with Vacuum Relief

The B400 Series ensures that tanks and vessels are kept safe during periods of excessive pressure due to external fire sources and also allows access to the tank for inspection / cleaning purposes.

  • Weight Loaded Pressure Only
  • Standard Pressure settings + 4 mbarg to 140 mbarg
  • Size range 8″ (200 mm) – 36″ (900 mm)
  • Weight Loaded Pressure / Spring Loaded Vacuum
  • Standard Pressure settings + 4 mbarg to 140 mbarg
  • Standard Vacuum settings -2 mbarg to – 50 mbarg
  • Size range 18″ (450 mm) – 36″ (900 mm)
  • Standard body materials – Aluminium, Carbon steel, Stainless steel
  • Standard trim material – Stainless steel
  • Diaphragm material – PTFE
  • Flanges – Drilled only API / ANSI / DIN / JIS / Specials
  • Hinged cover ensures automatic re seat
  • Steam Jackets
  • Proximity Switches to indicate pallet lift
  • Alternative materials for hazardous applications
  • Non standard applications consult factory


Low cost maintenance
Lightweight design provides easy handling whilst interchangeable components ensure standard parts are easily replaced

Testing / Quality
All products are factory tested and fully certified.

Self Draining
All products are designed so that any condensate drains away from seating areas.

Low leakage
Standard seating design ensures minimum leakage of less than 1 scfh at 90% of set pressure.

Internal Parts
Internal parts are stainless steel as standard. Non standard materials available upon request.

All valves are supplied with drilled flanges to meet individual requirements.

Non Standard Applications
There are numerous options available for special applications. Exotic materials such as Hastelloy and various plastics can be offered to suit the most hazardous of environments. Special coatings can be applied for extreme service. For low temperature duties, internal parts can be PTFE coated to prevent seizure.
See separate section in catalogue.
* All products are subject to continuous development and subsequently 3B Controls reserve the right to change specifications outlined in this catalogue without notification.

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