Thursday 24 December 2020

Plug Valve API 6D Explained

Programming interface 6D plug valve includes a barrel-shaped or conic circle, with one or various flat empty paths, that can be turned to open, close, or control the progression of the liquid through the valve. The most utilized sort is the two-port lubricated sort with an open and shut position. 


This valve includes a round and hollow or conic circle that controls the progression of the liquid, opening and shutting the path between the contrary ports. The switch to control the valve is put at the highest point of the body. 

These valves can be utilized for fluids or gases, for example, 

  • Unbiased fluids, similar to oil and water 

  • Acidic and Alkaline (destructive) fluids 

  • Slurry 

  • Unbiased gases, for example, steam and air 

  • Destructive gases, including chlorine and corrosive fumes 

A plug valve can be arranged with a flanged, center point or butt weld closes and with a cast (> inches) or a manufactured body material (< 2 inches breadth). 

The two key reference particulars covering this sort of valve, for petrochemical applications, are the API 6D (downstream) and API 6A (upstream). 

Plug valves might be physically worked, with a wrench or stuff or incited with Electric, Electro-Hydraulic, Pneumatic-Hydraulic and, Gas Over Oil Actuators. 


There are four primary sorts of plug valves, each with explicit highlights and advantages. 

Lubricated Plug Valve 

A lubricated plug valve utilizes an ointment to diminish the rubbing and seal the ports firmly. The grease is regularly a base oil that improves the consistency of the moving parts, as undefined or raged silica, which is infused between the plug face and the body seat at high weight. 

Makers suggest a sort of grease that coordinates the cycle liquid, and to reseal the valve after a specific number of cycles (or after each cycle for certain applications). 

Because of these support necessities, lubricated valves are utilized in applications that have non-consistent activities. This kind of valve suits measures with somewhat rough particles suspended in the liquid, for example, upstream applications, gas pipelines that require sidestep valves, and as blow-down valves on valve stations and kicker valves. 

This sort of plug gadget has, for the most part, metal seats. 


This valve includes a tightened or funnels shaped circle that goes about as a wedge and presses a delicate material sleeve against the body depression (the sleeve decreases the erosion between the plug component and body). 

Non-lubricated valves are liked to the lubricated sort when low upkeep is required, as in administrations for sulfur, hydrogen fluoride, or in situations where the liquids could set and hinder the valve. 

The disadvantage of non-lubricated valves is that they suit just explicit applications as far as temperature, weight, and type fo passed on liquids (synthetic opposition) because of the non-metallic seat they use. 

The three primary sorts of non-lubricated valves are: completely lined, elastomer sleeve and, lift-type plug valve. 

Twofold Expanding (Double Block and Bleed – DBB)

This is the most intricate plug valve plan, as it includes various segments that permit a mechanical development of the valve to give it a genuine twofold hinder and drain work. 

They are frequently used to forestall item defilement in applications that don't need twofold confinement. 

The extending valve utilizes a component that turns between the open and shut position and shields the two seals from the stream way. During the turn, the body and seals don't get in contact, and slips grow onto the body seat when the valve is shut to forestall wear or scraped area to the seals. 

Short versus Long Pattern 

There are three distinct plans of plug valves. 

  • The short example configuration type has reduced vis-à-vis measurements and port zones representing 40% to 60% of a pedal to the metal kind 

  • The customary example has more drawn-out eye to eye measurements and a port territory of 50-70% of the pedal to the metal plug valves and is intended to give negligible loss of stream. 

  • Pedal to the metal plan has gloomy look to confront measurements and around the port (Venturi). 

  • This last arrangement gives unlimited stream and permits pigging activities of the pipeline. Present-day plug valves are the advancement of an essential plan that was created back in the Roman domain. 


As a rule, a plug valve and a ball valve may clear a similar capacity (liquid shut-off). The primary contrasts are: 

  • plug valves are more affordable than ball valves, for the most part, because of their less complex plan 

  • plug valves are less inclined to defilement by trash, and collection of soil in the interstitial spaces, contrasted with ball valves (an issue that is as often as possible looked at by ball valves, because of the spaces existing between the circle and the body of the valve) 

  • ball valves require more upkeep than plug valves, particularly after arranged or impromptu plant shut-downs 

  • plug valves have a full port plan, without pressure drops, ball valves might be decreased or full port (a full port ball valve would be heavier and bulkier than a plug valve of a similar size) 

All in all, plug valves are acceptable choices to ball valves, regardless of whether ball valves are as yet considered the business standard for shut-off tasks at any rate in the oil and gas industry.

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