Wednesday, 3 July 2013

What is the distinction between a Double Block and Bleed and Double Isolation and Bleed valve?

Recent developments in API standards now allow the distinction between Double Block and Bleed and Double Isolation and Bleed valves.  Check out this interview and transcript with Fred Turco from Omni Valve, at Valve World.

Tuesday, 2 July 2013

Chevron packing for severe service valves in demanding petrochemical applications

Chevron packing is a valuable resource for industrial valves owing to its specific features like durability, high elasticity, tough resistive power and above all the ability to withstand high/low pressures.

Crane’s Xomox Tufline severe service valves, for example, use Chevron packing, particularly in valves designed for alkylation service.  These particular valves are made of carbon steel or monel body and monel trim which are required to withstand the corrosive nature of hydrofluoric acid (HF acid). Given the highly corrosive nature of HF acid service, alkylation valves require reliable packing making Chevron packing a reliable choice.
Xomox Tufline sleeved plug valve. Source:
Designing the seal

The Chevron packing seal consists of a base ring, V-ring and a pressure ring. All three rings are come together to form a seal that reacts to the pressure changes. The base ring is made of a cotton fabric mixed with nitrile rubber that ensures complete safety from the extrusion problems. This ring is then backed up by the V-rings which are also made from the cotton fabric as well as the nitrile elastomers, combined as per industry standards. The overall purpose of the packing is to increase the sealing efficiency and balance the load which is crucial for better performance. The third and last element of the packing are the pressure rings whose function is to distribute the pressure equally among the rings and protect its different, integral elements from disproportionate wear and tear.

Usually one base rings is combined with one or three V-rings followed by one pressure ring. The Chevron seals find their use in industrial applications as well as other robust and high-alloy valves.

Benefits of using Chevron seals

There are several advantages of using Chevron seals in monel valves or other packing solutions:

  • It has the ability to adjust to a broad range of demanding industrial applications.
  • Durability and lasting performance reduces down-time, cost-of-ownership and increases worker safety.
  • Despite wear and tear, the Chevron sealing and packing system will work well without adversely affecting performance.
  • Flexible to bear even the severe temperature and pressure conditions.

Chevron packing can be found in many different types of valves, but are of particular use in corrosion resistant valves designed for alkylation service and made of monel. Other industrial purposes of such seals include pumps, marine hydraulics, and injection molding machines. 

Tuesday, 16 April 2013

Hearts and thoughs going out to all those affected by the tragic events at the #bostonmarathon.

Sunday, 24 March 2013

Monel valves in petrochemical applications and... trumpets?

Monel valves in petrochemical and trumpets?

Did you know that the main two end uses of monel valves are world apart?  One of the main uses of valves made of monel is in the petrochemical industry.  Monel valves are particularly useful in oxygen service, as well as marine service in combination with aluminium bronze.  This corrosion resistant alloy is of particular use in alkylation processes where hydrofluoric acid eats through most metals, bar monel and hastelloy.

Monel valves are also used in.... trumpets!  Monel valves don't require being oiled frequently since oil evaporates faster on stainless steel compared to monel.  The drawback: price!

Saturday, 23 March 2013

Titanium valves: the link between the petrochemical and motorsports industries

Did you know that titanium valves are used both in petrochemical applications as well as in motorsports and aviation?  Valves made of titanium are ideal for certain acid applications in petrochemical processes; titanium is inert in some acid environments and the use of titanium valves ensures that the material doesn't react to the medium flowing through the valve.

Valve in titanium alloy
Valve made of titanium for nitric acid application
Weight is not an issue in the petrochemical industry, though titanium valves tend to weigh around half the weight of their stainless steel counterparts.  Weight, on the other hand, is a key issue in both motorsports as well as aviaion, though reaction to acid content isn't a concern here.  Titanium is great for motorsports, since less weight means more flexibility for manufacturers.  This, too, is true in aviation, with an added bonus: titanium has a very high tensile strength compared to stainless steels, and it also very brittle.  Fissures are therefore easier to detect before they become a serious problem.

Wednesday, 20 March 2013

Valves in duplex alloy

Valves made of duplex alloy are taken front and center stage at desalination plants.  We've noted a particular upswing in orders from Central and South-America, particularly in the development of new desalination plants and processes.

Valve made of duplex alloy; swing check configuration.

 We welcome this development and continue to serve our customers in this booming market!

Monday, 18 March 2013

Valves in Alloy 20 for corrosive petrochemical media

Valves in Alloy 20 for corrosive acid processes

The use of valves made of Alloy 20, such as A351 CN7M or B462 N08020, has shot up over the past few years. New applications have been found for Alloy 20 - sometimes identified as Carpenter 20 - which has proven relatively inert against high concentrations of nitric acid up to 60ºC, as well as heated though diluted oxide.  Alloy 20 valves can also be used in acetic acid alkali and diluted hydrochloric acid; they are also found in hydrofluoric acid applications (HF acid) at alkylation plants.

Valves made of Alloy 20
Alloy 20 gate valves from The Alloy Valve Stockist (Barcelona)

The Alloy Valve Stockist, headquartered in Barcelona, Spain,  is constantly expanding its inventory of Alloy 20 valves to include a wide range of gate, globe, check, ball and butterfly valves.  Plug valves are also available in Alloy 20 material.

Wednesday, 13 March 2013

Barça moves on to Champions League quarter finals after subduing Milan

What a spectacular game last night, and a priviledge to watch together with friends and industry colleagues!

Last night, Barça came back from a 2-goal away-field disadvantage to clinch a solid 4-0 homegame victory over Milan.  The two teams were playing the second leg of the final-sixteen-team Champions League.

Game was mesmerising!

Wednesday, 27 February 2013

Substantial valve order on its way!

Just closed a substantial order for some metal-seated titanium ball valves for South American plant.  Delivery is tight: 7 weeks; it will be done!

Metal-seated titanium ball valves

Thursday, 21 February 2013

HF Acid Valves for corrosive alkylation service

HF acid valves designed for alkylation service at plantes designed according to UOP and ConocoPhilips licenses are one of the most corrosion-resistant category of valves available on the market.

Only a handful of manufacturers have been approved by UOP and ConocoPhillips for use under their license.  End users are obliged to use hf acid valves made by these manufacturers alone, and otherwise risk to loose the licensor's guarantees for the safety of the plant and the integrity of the alkylation process.

Although alkylation valves are made of relatively common steel -- they either come in carbon steel body and monel trim, or monel body and trim -- they also come with a series of safety and performance features that are unique to these valves. For the time being, only gate, globe, check and plug valves are approved for UOP and ConocoPhillips alkylation plants.

Other materials used at alkylation plants often follow NACE norm 5A-171 "Materials for Storing and Handling Commercial Grades of Aqueous Hyrofluoric Acid and Anhydrous Hydrogen Fluoride". This norm os one of the most demanding ones in the process industry.


Wednesday, 20 February 2013

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