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DBB Dual Expanding Plug Valves

Double Block and Bleed (DBB) Dual Expanding Plug Valves are a specialized type of valve widely used in the oil and gas industry. Its design incorporates two expanding plugs that create robust isolation barriers in both the upstream and downstream flow direction, and a bleed mechanism that allows for pressure relief or seal verification.


Working Mechanism:


Dual Expanding Plug: This valve contains two plugs that can be mechanically expanded against the body of the valve. When in the closed position, the plugs form a positive, mechanical seal on both the upstream and downstream sides of the valve, ensuring a tight seal even under low pressure or vacuum conditions.


Double Block: The term “double block” refers to the valve’s ability to create two isolation barriers in a single unit. This important safety feature ensures secure containment of process media.


Bleed Function: The “bleed” function allows for venting or draining the cavity between the two plugs. This feature helps to relieve pressure or verify the integrity of the seals, ensuring safe operation and maintenance of the valve.


Application features:

  • Superior Isolation: The dual expanding plug design provides two isolation points, offering enhanced safety and preventing potential cross-contamination of fluids.
  • Pressure Control: The bleed function allows pressure relief, which can be crucial in preventing overpressure scenarios and in verifying the integrity of the seals.
  • Safety Assurance: The double block and bleed feature provides redundancy and safety assurance, especially important in critical applications such as the oil and gas industry.
  • Versatility: Despite being primarily used in the oil and gas industry, these valves can also be useful in other industries requiring stringent isolation and pressure control measures.
  • Robust Design: The mechanical expansion of the plugs ensures a tight seal, making these valves suitable for a wide range of pressure conditions, including low-pressure or vacuum environments.
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Karma Instrumentation & Control is a specialist supplier of process control and automation equipment and SI systems, as well as a manufacturer and designer of process and electrical control panels.

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