|Arrow Type Float Valve is normallyl installed in a standard bore-back of the bit sub,to provlde fluid flow control at the bottom of the friII stem. It also prevents backflow of cuttings from plugging the drilI bit jets while making connections Its 70Mpa(10 000psi)working pressure complements today. high pressure BOPstacks.
Where the flapper is held open by the built-in latch, the drill pipe fills form the bottom. This eliminates the mess and lost time of fiIling operations,running in with the flapper open also reduces the potentical of formation damage from pressure surges caused by the bit acting as a piston or ram as it is lowered into the hole. The flapper is latch is automatically released by initial circulation of drilling fluid through the valve.
During normal circulation,the flapper os fully open and out of the way,The large bore of the valve provides minimum flow restriction.
When circulation is stopped The flapper is closed by the flapper spring Preventing backflow through the bit.
When run in the closed position,the Valve allows the drilI pipe to be floated in while only partially filied with fluid.This lowers the effective weighI of the drilI string and reduces strain on rig equipment.
The Float Valve Sub is a bit sub in which a float valve is be installed.Its connections is ordered by usere. The Supplier put a Float Valve into the bore of the sub according to specification of standard API Spec 7.Mechanical property of material of sub conforms to the requirement of standard SY5200 2002 and API Spec 7.