Double Block and Bleed Valve

June 27, 2023

The increased activity in the offshore sector of the energy industry has led to additional factors that have to be taken into consideration when designing piping systems. Space in these modern locations is always at a premium and the design of piping systems and their associated components must therefore be more compact.

Features

Live Loaded Gland Packing

Graphite Packing are provided as standard taking care of Fire Safe Design Condition. Belleville Springs Washers are used to achieve live loading which protects Gland loosening under vibrations & shock conditions.

Antistatic Device

To ensure Electrical Continuity between the Stem and Ball and Body all Valves are provided with Antistatic device as an integral part of Floating Ball Valves.

Blow Out Proof Stem

Stem is Designed to include a collar to provide protection against Blow Outs.

Double ‘D’ Stem to Lever Connection

Stems are Designed to have Double ‘D’ Connection at the top for Lever Fixing. This feature eliminates possibility of Lever Assembly in the wrong direction as the Lever indicates the Valve Position once installed on the line.

Equalized Cavity Pressure

The Pressure equalization hole at the top of the Ball combined with Seat Design are Engineered to maintain the Pressure balance in the line & in the Body Cavity irrespective of Valve Position

Details

There are structural constraints that are also very important, such as keeping the structure as light as possible, and there are obvious benefits from making components smaller and lighter. Construction site job is also very expensive and any reduction in installation manpower is also beneficial. The above situation has led to the modification of the patterns of valve components to incorporate savings in space, weight, and labor costs where possible, while still retaining the original function of the valve.

The greatest savings are to be seen in the reduction of leak to atmosphere because the potential leak points are minimized compared to the conventional design. Process isolation philosophy has become more complex as safety issues have to be addressed and the requirement for double block and bleed isolation has become more commonly used. Double Block and Bleed isolation requires two in-line isolation valves and a bleed valve, used to drain or vent trapped fluid between the two closure elements

Design & Testing Standards

Design Standard:

ASME B16.34
API 6D
BS -5351
ISO 17292
ISO 5211 (Mounting Pad)

End Connection Standards

Face to Face : Manufactured & Standard
Flange Dimensions : ASME B16.5, EN 1092 , JIS B 2220
Butt weld End Dimensions : ASME B16.25,
Socketweld End Dimensions : ASME B16.11
Screwed End Dimensions : ASME B 16.11

Testing Standards

Pressure Testing : API 598, API 6D, ASME/FCI 70.2, EN 12266-1, ISO 5208
Fire Testing : API 607 / API 6FA
Nace Requirements : MR 01-75
Fuggitive Emission Testing : ISO 15848-2