Triple Offset Valve is A Premium Process Valve Made to the Highest Standards

Triple Offset Valve Technology

Enhance operations with a design that eliminates any rubbing action of the sealing elements during the 90 degrees of rotation

Our Triple Offset Valve is A Premium Process Valve Made to the Highest Standards

Triple offset valves with minimum/zero maintenance requirements, represent the definitive solution for countless piping, process and instrumentation engineers around the world.

A virtually maintenance free valve that not only delivers uncompromising performance, but can provide a more efficient solution compared to ball, gate and plug valve designs.

How Triple Offset Valve Works

Triple Offset Design

The Vanessa Series 30,000 valve shares the same cone-to-cone principle with a globe valve, but sealing is performed by quarter turn rotation. TOVs use a sealing system consisting of a stationary seat and a rotating sealing surface sharing an identical shape: an inclined conic section. When these cones overlap, closed position is reached and sealing occurs. Such 'quarter turn globe' concept is made possible by the use of three 'offsets' meant to completely eliminate rubbing. Optimized seating angles and rotational characteristics guarantee superior tightness via an ingenious combination of the triple offset design and a flexible metal seal ring across all basic, cryogenic and high temperature configurations.

Offset 1

The shaft is placed behind the plane of the sealing surface to provide a continuous seat path.

Offset 2

The shaft is placed to one side of the pipe/valve centerline to allow the displacement of the seal from the seat during the 90° opening.

Offset 3

The seat and seal cone centerlines are inclined in respect to the pipe/valve centerline. This third offset completely eliminates rubbing.

Torque Seated

Vanessa's seating force is generated by externally applied torque rather than by mechanical interference as in position-seated ball, butterfly and plug valves. This means that the cone-to-cone sealing occurs by contact pressure and not by friction generated by the elastic deformation of the seat. This feature allows our valve to handle high pressure classes and provide reliable and highly controlled operating torque. Our trim design, seating angles and surface finish all contribute to a very low, consistent and predictable torque demand which is unaffected by fluid temperatures and pressures throughout the valve life. The non-rubbing rotation ensures low and constant running torque across the 90 degree rotation so that the operating torque calculated and tested on a newly manufactured product is equal to a comparable fully operational valve.

Metal-to-Metal Seating

Metal-to-metal sealing ultimately ensures that the valve can handle virtually all possible temperatures, pressure levels and fluid types. We use a Stellite® grade 21 seat and a resilient seal ring in Duplex as a minimum with high mechanical resistance. Stellite® 21 is a cobalt alloy that coats the body seat to provide hardness, resistance to fluid abrasion, corrosion and general wear. Due to its unique design, the metal seal ring has elastic properties which allow for radial compression to be uniformly distributed around the seating surface. These are key contributors to the zero leakage performance of the valve.

Stellite® is a registered trade name of Deloro

Quarter Turn Rotation

A quarter turn rotation means significantly lower and more consistent running torque compared to any rising stem design, ensuring that Vanessa TOVs can achieve extremely quick stroke times. This also eliminates any negative effects on packing caused by rising stems, such as extrusion and abrasion, and ultimately provides for a more compact valve design.

Non-Rubbing Rotation

Eliminating contact between seat and seal during opening-closing means extending the life of the sealing elements and the valve altogether. This also combines with the main feature of quarter turn rotation, i.e. low and consistent running torque, for which valve operation remains quick and easy over time and modulating is possible even at extremely low angles. The ability of handling quick stroke time requirements and a high number of cycles is also correlated to the valve non-rubbing feature. Users can ultimately reap the critical benefit of longer lifecycle of the sealing elements compared to other valve designs.

Available Configuration

Valves construction

Series 30,000 is a robust valve capable of performing bidirectional zero leakage notwithstanding extreme temperature conditions. Indeed, its all-metal construction, inherently fire resistant, is unaffected by temperature changes and a fully integrated long bonnet keeps packing protected from extreme service temperatures (from -60 °C to 450 °C - from -76 °F to +842 °F).
Furthermore, the flange spot facing ensures flange bolting nut and washer planarity, increases reliability and safety of flanged joints with long term tightness and no re-tightening requirements.

Sealing components

The materials chosen for sealing, coupled with precise machining, significantly contribute to extending the life of the valve. Every Vanessa Series 30,000 valve in basic configuration features a smoothly grinded seat with Stellite^® grade 21 weld overlay highly resistant to galling, abrasion, erosion and corrosion.

The Vanessa seal ring is the key flexible component necessary to perform sealing and may be laminated in Duplex (as a minimum) or manufactured as a one-piece solid. Seal rings are easily interchangeable thanks to their self-centering ability and the presence of reference pins that simplify assembly. In addition, a dynamic spiral wound gasket ensures an adequate expansion and contraction of the seal ring during opening and closing.

Trim

Vanessa valves all share the same trim – a combination of optimized angles, and robust bearings and shafts. Our engineers have developed over four decades each and every component to maximize safety while keeping an extremely streamlined and functional design:

The one-piece shaft maximizes robustness to a level which is not reachable with stub shafts commonly used with low pressure butterfly valves.
Two-piece packing glands enhance safety and reliability in terms of fugitive emissions over time.
The shaft to disc connection is secured by keys (no pins) to optimize torque transmission without compromising shaft integrity.
The disc is not a sealing element, only a carrier. Being consistent with body material, the disc can be exposed to the same level of abrasion and corrosion of the valve body without negative effects on tightness and operability.
Heavy duty bearings and thrust bearing are designed to withstand high pressure loads and wear.
- Standard reinforced, braided and flexible graphite bearing protectors eliminate the risk of particle intrusion, ensure constant torque demand and increase overall reliability.
Internal and external retaining devices ensure Vanessa blowout-proof one-piece shaft is safe to operate and provide complete compliance with API 609.
Open/closed disc references and an external disc position indicator simplify installation/removal procedures and are in compliance with API 609.

Optional features

Series 30,000 basic configuration is available with several options:

A packing flushing device is usually added whenever the fluid involves high health & safety risks – through this connection a pressure chamber and/or a suction point can be created to eliminate or intercept any leakage.
A live loaded mechanism minimizes the need to tighten the packing whenever the valve is used in heavy duty applications (including thermal cycling) or packing maintenance is not practical.
Top and bottom bearings can be protected from dirty or polymerizing/crystallizing medium by flushing devices which create a barrier by means of a clean fluid injection, providing additional operational safety and reliability.
A one-piece metal Solid Seal Ring (SSR) is chosen whenever the application may negatively affect the life of the standard laminated seal ring. SSRs are a standard feature in high pressure, cryogenic and high temperature configuration.

Stellite^® is a registered trade name of Deloro

Cryogenic configuration

Our cryogenic configuration has been designed in order to operate with temperatures down to -254 °C (-425.2 °F). The following features differentiate Vanessa Cryogenic Series 30,000 from the basic configuration:

Vanessa seal ring is always a one-piece solid in Nitronic^® 50 (Solid Seal Ring) - a material highly resistant to corrosion able to preserve important mechanical features at low temperatures. Nitronic^® 50 also has exceptional yield strength, approximately double that of other series 300 stainless steels at ambient temperature.
An extended bonnet keeps packing protected from cryogenic service temperatures down to -254 °C (-425.2 °F), meeting the requirements of BS6364 for non-cold box applications and major end user specifications.
Cryogenic valves are available in Double flanged, lug, buttweld and buttweld top entry body styles:
- Double flanged body
  The most widely used pipe connection - it enables the best gasket load distribution and short bolting reduces the risk of stretching. The standardized flange design also ensures safe pipe jointing and ease of assembly/disassembly from the line. Vanessa provides ASME and EN flanges including designs to ASME VIII sect 2 div.1.
- Buttweld body
  The ideal choice whenever flanged connections need to be reduced, this design provides significant initial cost savings. The buttweld body completely eliminates the possibility of fugitive emissions through flanged joints induced by the adjacent pipe stresses. As for all Vanessa valves, ongoing maintenance is not required.
- Lug body
  A single flange design and more economical than Double flanged, as it requires less material. With threaded inserts on both sides, it is installed using two sets of bolts and no nuts. According to common industry practices, operators tend to avoid using this body style for diameters higher than NPS 36 due to operational difficulties in installing the valve.
- Buttwed top entry body
  When an inline maintenance capability is mandatory, this design allows for access without removing the valve body from the line. The entire valve trim can be removed from the body and individual valve parts can be accessed in total safety. This feature allows for any unpredictable and extraordinary valve repair, which would be impossible, impractical or unsafe with different valve designs. Overall, the maintenance of a Vanessa valve remains largely unnecessary throughout the product lifecycle.

Nitronic^® is a registered trade name of AK Steel

High Temperature configuration

Our high temperature configuration has been designed to operate with temperatures up to 815 °C (1,500 °F). The following features differentiate Vanessa High Temperature Series 30,000 from the basic configuration:

Vanessa seal ring is always a one-piece solid in different materials depending on the valve body - this ensures no graphite oxidation and weakening, while allowing for various hard facing technologies to be applied in order to respond to application risks.
A bolted extended bonnet keeps packing protected from high service temperatures up to 815 °C (1,500 °F).
Bearings and thrust bearing can be hard faced with Stellite® or other overlays ensuring high mechanical properties and responding to application risks.
All materials, including disc bolting, are selected to guarantee suitable mechanical properties in high temperatures and consistent thermal expansion rates.

Stellite^® is a registered trade name of Deloro