Showing posts with label triple offset valve. Show all posts
Showing posts with label triple offset valve. Show all posts

Friday, November 16, 2018

What is a Triple Offset Valve (TOV)?

Triple Offset Valve
Click for larger view.
As the name implies, there are three separate offsets designed into the triple offset valve. Two of the offsets apply to the location of the shaft with respect to the center line of the bore and the center line of the disc/seat sealing surfaces.

The third offset in the design is the axis of the seat cone angle that is inclined from the center line of the valve bore. This eliminates rubbing of the seat/seal contact surfaces during operation and preserves sealing integrity over the cycle life of the valve.

The contact is made in only the final point of closure, acting as a mechanical travel stop which prohibits over-travel of the disc.

Applications and Method of Control

A triple eccentric or triple offset butterfly valve should be used when the application requires bubble tight shut-off, but does not allow the use of a rubber-lined butterfly valve due to low/high temperatures and high pressure. The triple offset design can be used for on/off services, throttling services and modulating services.

On/Off Service
Like the name suggests, on/off valves are designed to shutoff and to open fully but lack the ability to to regulate effectively through the range of travel.

Throttling Service
Throttling service (sometimes referred to as inching) is in general flow control through the system where the valve is set and held in an intermediate position.

Modulating Service
Modulating service (known also as regulating service) is used to drive the valve frequently to any position between fully open and fully closed to control the flow. It uses feedback from the field, and valve disc position is adjusted almost continuously.

Quarter turn valves are usually limited to a throttling range of ~25° to ~75° open (25% to 85%). In case of throttling the manufacturer should be consulted in order to predict whether the control valve was installed accurately.

For more information, contact Mountain States Engineering and Controls. Visit their web site at https://mnteng.com or call 303-232-4100

Thursday, January 25, 2018

Krombach Brand Valves for Rugged Service Conditions

metal seated butterfly valve with actuator
Metal seated butterfly valves for aggressive process
applications are a hallmark of the Krombach brand.
Image courtesy Crane CPE
The Krombach branded valves, part of the Crane CPE product offering, target challenging applications in industrial settings that benefit from the use of valves specially designed for severe service. The brand also includes a standard product offering of valves and specialties for a broad range of common industrial applications.

The Krombach line includes:

  • Butterfly Valves - High performance, resilient seated, double-eccentric, triple offset and special purpose butterfly valves.
  • Ball Valves - Process one-piece, two-piece and three-piece, metal seated, soft seated and compact ball valves.
  • Globe and Angle Valves - Bronze, cast iron, cast steel and stainless steel globe and angle valves.
  • Gate Valves - Bronze, cast iron, cast steel and stainless steel gate valves.
  • Check Valves - Ball, dual-plate, foot, full body swing, steam stop, tilting disc, wafer style swing, nozzle-type and pressure seal check valves.
  • Vacuum Relief Valves - Available with flanged or threaded connections.
  • Aerating and Deaerating Valves - Essential for trouble-free operation of pipeline systems handling liquids.
  • Float Valves - Single seated and double seated versions for a variety of applications.
  • Throttle Valves - Available with flange connection, wafer- or weld-in type.
  • Bottom Drain Valves - Available manually operated or with a diaphragm actuator.

Below is a cutsheet providing an overview of the company's standard product categories. Whatever your fluid control application, share your challenges with the valve specialists at MSEC. Leverage your own process knowledge and experience with their product application expertise to develop effective valve and automation solutions.


Friday, April 15, 2016

New Triple Offset Valve From Crane

Triple offset butterfly valve for industrial process control
FKX 9000 Triple Offset Butterfly Valve
Courtesy of Crane CPE
Crane ChemPharma Energy, a globally recognized manufacturer of industrial process control valves for an extensive range of industries and applications, has developed and released a new addition to its line of triple offset butterfly valves. The FKX 9000 series incorporates innovative design features to bring longer valve life, cost reduction, and superior performance in industrial applications where high temperature, high pressure, and severe service are present.

The new valve series is available in sizes ranging from 3" to 24", with three body configurations and a host of special options for tailoring to specific applications. A flyer is included below that highlights the features of the new valve. More detailed information, as well as help with meeting all your fluid process control challenges, is available from the product knowledge and application support specialists at Mountain States Engineering.


Tuesday, November 17, 2015

Mountain States Engineering and Crane Expand Their Relationship

Triple Offset Butterfly Valve
Krombach Triple Offset Metal Seated Valve
Courtesy Crane CPE


Mountain States Engineering and Controls has been selected as the new distributor of the Krombach branded valves from Crane CPE. MSEC has been a master distributor for various brands in the Crane family for fifteen years, and will be capitalizing on knowledge and experience gained from their many years of providing solutions in the industrial process control and valve fields. The Krombach branded valves complement the applications range of other industrial valves handled by MSEC.

The Krombach line includes:
  • Butterfly Valves - High performance, resilient seated, double-eccentric, triple offset and special purpose butterfly valves.
  • Ball Valves - Process one-piece, two-piece and three-piece, metal seated, soft seated and compact ball valves.
  • Globe and Angle Valves - Bronze, cast iron, cast steel and stainless steel globe and angle valves.
  • Gate Valves - Bronze, cast iron, cast steel and stainless steel gate valves.
  • Check Valves - Ball, dual-plate, foot, full body swing, steam stop, tilting disc, wafer style swing, nozzle-type and pressure seal check valves.
  • Vacuum Relief Valves - Available with flanged or threaded connections.
  • Aerating and Deaerating Valves - Essential for trouble-free operation of pipeline systems handling liquids.
  • Float Valves - Single seated and double seated versions for a variety of applications.
  • Throttle Valves - Available with flange connection, wafer- or weld-in type.
  • Bottom Drain Valves - Available manually operated or with a diaphragm actuator.
I have included below one of the many comprehensive data sheets available. More information on any application or product is available from the process control specialists at MSEC. Combining their product knowledge with your process mastery is the key to positive outcomes.

Monday, September 28, 2015

Triple Offset Valves - Some Advantages and Considerations

Flowseal brand triple offset butterfly valve
Triple Offset Butterfly Valve
Courtesy Flowseal, Crane CPE
Industrial process control often involves the control of fluid flow, ranging from slurries or petroleum to highly refined liquids and gases. The enormous variety of application specifics has given rise to a wide range of valves with performance characteristics to match those requirements. One common valve type is the butterfly valve. In it's simplest form, it is a disc located in the path of fluid flow that is connected to a shaft. The disc rotates through a 90 degree arc to present either its face (valve closed) or its edge (valve open) to the fluid flow path. I wrote about some advantages and disadvantages of butterfly valves a couple months ago under the title "Is a Butterfly Valve Right for Your Application?".

There is a variant of the simple version of the butterfly valve that provides distinct advantages for many applications. Referred to somewhat officially as a triple offset butterfly valve, it can also be more commonly called simply a triple offset valve.

How is a triple offset butterfly valve different from a basic butterfly valve?


The triple offset valve does away with the centric alignment of the shaft and disc, using instead a shaft mounting arrangement that relocates the shaft axis off both the center of the disc and the center of the bore. This shaft positioning, while creating a larger flow obstruction in the fully open position, sets the disc movement path in the proper alignment to take advantage of the third offset, which is the sealing surface. Triple offset valves have a different seals than other butterfly valve variants. There is an angular sealing surface, the angle of which is determined by sectioning an imaginary right angle cone shape that extends along the bore. However, the apex of the cone does not lie on the center of the bore. This inclination of the seal cone constitutes the third offset. You can see an illustration of this description in the document included below.

What advantages might those differences bring to your application?


  • Triple offset valves have discs that do not contact the sealing surface until the valve is closed. This is in contrast to other butterfly valve designs, which have contact between the disc and resilient seals for part or all of the disc travel, along with the associated friction and wear.
  • Elastomer or other similarly resilient materials are not needed to provide a zero-leakage, bubble tight shutoff. Sealing is generally accomplished with metal-to-metal contact.
  • Friction free stroking of the valve disc. Actuator power requirements may be reduced.
  • All metal construction provides elements of corrosion and heat resistance not found in other butterfly valve designs with resilient seals.
  • This valve is torque sealed, not position sealed like other butterfly variants. Actuator torque forces the seal of the machined metal surfaces to produce tight shutoff.
  • No breakaway torque requirement, since the disc is not contacting resilient seals. 
  • Seating arrangement prevents overstroking of the valve, a potential problem with other butterfly valves.
Different manufacturers may have slightly different feature sets, but this should help you consider the benefits of this butterfly valve variant. Though its initial cost may be higher, the expected lower maintenance requirement, longer service life, and better performance may be well worth it. Talk to a valve product specialist about your application. I've written many times that combining your process expertise with the up to date product knowledge of a professional sales engineer will produce a positive outcome.