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VCS flange Insulation Gasket

The VCS gasket is a high reliability gasket used for both insulating and general sealing purposes in very critical services. The gasket has a proven track record of integrity in aggressive sealing situations. The VCS is suitable in all services up to and including ANSI 2500 and API 15,000 classes.

Each VCS gasket can be supplied independently or part of a flange insulation set that comprises one central insulating gasket, one insulation sleeve per bolt and two insulating and two plated steel washers per bolt.

General Properties

  • Flange insulation in conjunction with cathodic protection
  • Mitigates galvanic corrosion in dissimilar metal flange joints
  • Mating mismatched ring-joint to raised-face flanges (VCS will seal in ring joint, raised-face and flat face/slip-on flanges)
  • Withstands corrosive environments including high CO2, H2S and produced water
  • Matched bore construction protects flange faces from media-induced corrosion and flow-induced erosion
  • Pressure energised seal reduces the flange makeup stress
  • Easy installation and removal
  • Reusable seal retainer and seals
  • Suitable for all ANSI and API rated flanges
  • High strength laminate material resists failure due to overcompression

Materials

Metallic Core316 Stainless Steel (Duplex & Inconel available)
Gasket Insulating MaterialG-10 Glass Reinforced Epoxy (GRE) as standard (G-11 available)
Seal MaterialSpring-energised Teflon as standard (Viton available)
Insulating Sleeve MaterialGRE as standard (Mylar available)
Insulating Washers MaterialGRE (standard)
Steel Washer MaterialZinc Plated Steel as standard (stainless steel available)

VCS Design

The unique and patented design of VCS gaskets incorporates high-strength, glass-reinforced epoxy laminate bonded to a stainless steel core. This provides the strength of a traditional metallic gasket while maintaining complete electrical insulation between the flange faces. Seal grooves are machined through the laminate insulating material and into the stainless steel core. This provides a strong base for the seal to sit into and breaks the potential leak/weep path that is inherent in glass laminate materials. Spring-energised Teflon internal face seals are installed in the dovetail-shaped seal grooves to provide the trademark pressure-activated sealing performance distinguishing the VCS from all other high pressure insulating gaskets.

Electrical Insulation

In addition to its superior sealing characteristics, the VCS distinguishes itself by providing electrical flange insulation in a high-strength gasket. The VCS significantly decreases electrical potential between two flange faces by providing a non-conducting, non-metallic interface. This effectively eliminates corrosion resulting from dissimilar metals contact or ground current induced corrosion of metal piping components. When used with insulating sleeves and washers, the VCS is particularly effective in breaking electrical conductivity in piping systems with cathodic protection systems.

What makes VCS unique among insulating gaskets is its strength and durability. Traditionally insulating gaskets have been fragile and prone to failure because they are often made from brittle non-metallic materials (e.g. phenolic resin) and are not capable of withstanding imperfect installation practices. The VCS’s steel core and patented construction enables the gasket to withstand much more system pressure, pressure cycling, bending moments, over torquing and overall abuse than conventional insulating gaskets with zero risk of product failure.

Sealing Characteristics

The primary job that any gasket must perform is to seal the pressure differential between the internal and external environment. The VCS performs this task through the use of its spring-energised, pressure- activated sealing elements. At low system pressure, the spring acts to deflect the lips of the seal, thus enabling low pressure sealing. As the pressure increases and comes in direct contact with the sealing element, the system pressure energises the lips of the seal against the flange face and stainless steel core. The greater the pressure, the more sealing force is applied against the flanges. This high pressure sealing is accomplished while maintaining complete electrical flange insulation. This high makes the VCS the gasket to use when failure cannot be tolerated.

The fact that the VCS uses pressure-activated sealing elements which are located inboard of the ring groove on RTJ flanges has the additional benefits of allowing the VCS to seal mismatched RTJ to raised face or flat faced flanges. This feature is very useful when replacing valves using stock inventory that may have a different flange face than the mating flanges.

VCS Flange Insulation Kit Components

The VCS gasket is a high reliability flange kit designed for electrical insulation & sealing in very critical service. The gasket comprises a composite seal retainer material bonded to a high integrity metal core. Spring energized radial face seal offers excellent salability at low loads.

Insulation Kit Contents

Insulating facingG-10 glass reinforced epoxy resin
SealSpring energised PTFE (Viton also available)
CoreStainless steel 316
Thickness1/2” to 5” 6.2mm, 6” to 72” 7.8mm, API 10,000 6.22mm.
Insulating WashersG-10 glass reinforced epoxy resin (other materials are available) 3.2mm thickness 2 washers per bolt
Steel WashersZinc-plated steel, 3.2mm thickness (stainless steel washers also available) 2 washers per bolt
Insulating SleevesG-10 glass reinforced epoxy resin, wall thickness 0.75mm (Mylar and Nomex also available) 1 insulating sleeve per bolt

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