The 'bean' is the restriction in a choke valve. A choke is a constant pressure control valve, so that down stream pressure is separated form upstream pressure. Bean size is traditionally measured in 64ths of an inch, so if someone talks of a 32 choke, the hole is 32/64" in diameter, ie half an inch. Usinally the maximum bean size is limited by the size of the choke valve- if you have a 1 inch choke valve, you can't have more than a 64 bean in it!
Bigger bean, means bigger hole, means more production, (provided the flow through the choke is still in critical flow, ie the flow velocity through the choke is still greater than the sonic velocity).
Try the manufacturer's websites: Anson, Masterflo, for picture of choke valves etc.
Other manufacturers include Varco, Cameron, Cor-Val, etc. Some manufacturers will give you free sizing software, others will calculate the size. Let them know if you speak of a fixed or variable choke.
There are many standard choke and bean patterns based upon expired patents from 70 years ago. Many oilfield supply houses stock the common beans.
The choke is used to drop lot's of pressure through a replaceble part, the bean, that errodes over time. I have used fixed chokes downstream of blowdown valves on an offshore gas processing platform. They are commonly used near the wellhead.
Friends,
Many thanks for all ur feedback. One step ahead, unlike normal choke valves, what are specialities of Mokveld valves used in offshore industry? I have been trying to gather more info....But would like to know the internal parts and how accessible internals are for an inspection?
I have seen Mokveld proposed for liquid pipeline surge valves. Nothing special comes to mind for offshore applications where Mokveld would be advantageous. Perhaps advantages exist on a Royal Dutch Shell platform, perhaps.
