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Chemical Process Technology

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Monday, November 12, 2007

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Dbl_Butterfly_valve


I would think it is not proper to provide butterfly valve downstream of Pressure relief valve.

i) Isolation : This valve will shut close during Pressure relief valve inspection & testing. Wear-n-tear on butterfly valve seat will generally caused the valve can not be properly tie shut-off. Leakage and back-flow from downstream facilities i.e. flare poses potential hazard to operator and maintenance crew.

ii) Full passage area : Butterfly valve with valve disk in the middle can not provides 100% full area for relief flow passage. Full bore ball valve is generally can provide full area for relief flow passage.

iii) Internal blockage : Butterfly valve disk may be disconnected from the valve body without awareness of operator. It potential create partial or total blockage of the relief flow path which shall be avoided.

iv) Additional pressure drop : Even though the butterfly valve is full opened, as it can not provides 100% full passage area, additional pressure drop is observed on the line. It will crucial for inlet line with low set pressure system.

v) Solid accumulation : If the process fluid contains particle or solid, there is potential particle & solid settle at the valve disc, slow accumulation may increase partial blockage of the relief path.

vi) High potential of valve damage : As the valve disc is located in the center, large relief flow is impacting the disc. This increase the potential of valve disc disconnect from the valve body. Compare to full bore ball valve, this possibility is close to nil.

Ball valve is commonly used for Pressure Relief Valve isolation.

What do you think ?



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posted by Webworm, 7:49 AM

2 Comments:

Anonymous industrial equipment said...

Complex control systems using valves requires an automatic control based input of an actuator. The actuator strokes the valve allowing the valve to be positioned accurately and allowing control over a variety of requirements.

September 4, 2009 at 12:55 AM  
Blogger Sude said...

Industrial Butterfly Valve with Electrical Actuators
Dilution Valve for Paper Industry | Sluice / Gate Valve with Pneumatic, Hydraulic and Electrical Actuators | Industrial Plastic Butterfly & Ball Valves with Pneumatic and Electrical Actuators | Flush Bottom Valves with Pneumatic and Electrical Actuators | Plug Valve with Pneumatic and Electrical Actuators

For more details please visit http://www.sudeengg.com/index.php?option=com_content&view=article&id=397&Itemid=431

January 20, 2012 at 10:21 PM  

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