Double Block & Bleed Valves

Double block and bleed (DBB) valves are a compact solution for an arrangement which traditionally requires multiple valves. This compact solution results in savings relating to cost, weight and space. All of which are very appealing to pipeline designers.

DBB valves can be defined by two cases. The first case being a single valve with two seats that when closed, seals against pressure and flow in both directions, allowing the cavity/vent to be drained. The second case is where the valve body consists of two isolation valves and a needle valve located between the two isolation valves. This needle valve allows draining to occur when the isolations are utilised.

DBB valves can be used in a variety of applications including:

  • Chemical injection (if the injection quill design is used)
  • Sampling
  • Maintenance
  • Flow diversion

PAC valves can be designed with end conditions to meet your specific piping and instrumentation requirements. Whether this is a flanged valve or flanged by threaded or any other unique combination. Working with our manufacturer’s we are able to ensure that your design requirements are met.

Double block & bleed valves are widely used throughout the Oil & Gas industry as the need for reliability and quality is key. PAC works very closely with its South Korean and European manufacturer’s to ensure the correct valve is selected and designed for the customers application, rather than just supplying a “commodity” item. In this way, PAC is able to ensure the suitability of the valve for the customer’s application, whilst also ensure a high level of quality is maintained throughout the manufacturing process.

Types:

Injection quill, ball-needle-ball, needle-needle-needle and ball-ball-ball

Materials:

Forged and cast materials including cast/ductile iron, carbon steel (including low temperature service), stainless steel, duplex stainless steels, alloys (ie. bronze, brass), exotic alloys (ie. Monel, Hastelloy, titanium)

Rating:

ASME Class 150 to 2500lbs and API 6A 5,000 to 15,000psi