single assembly, they provide weight and space savings, along with other benefits including reduced potential leak points and safer hook-up. This more compact and efficient arrangement reduces not only pipework vibration and associated stress but also installation and maintenance

costs.

Process Monoflanges:

They are designed to replace the traditional primary isolation valve. The primary isolate valve is of outside screw and yoke construction (OS&Y bolted bonnet) and is designed to ASME VIII and ASME B16.34 specifications.

The most frequently used DBB configuration is combining a primary isolate piping valve with the instrument block and bleed functions in one body. Bleed and secondary isolate valve are typically standard needle valve designs (screwed bonnet).

Instrument Monoflanges:

They are close coupled to a pre-installed primary isolation valve to provide a compact Instrument Double Block and Bleed Valve or are used when primary isolation valves with an OS&Y bolted bonnet are not required. Instrument Monoflanges are provided with the standard needle valves (screwed bonnet).