A self-flushing subsea hydraulic coupling having a pair of interconnectable male and female and members and a flushing port for flushing the hydraulic line connected to one of the members. Each of the members includes a poppet valve, the poppet valve of the member not designated for flushing being sealed during the flushing operation. During the flushing operation, the male member is partially withdrawn from the female member receiving chamber so that its leading face passes the flushing port. Flushing fluid passes through the hydraulic line connected to the member, through the poppet valve, into the receiving chamber and out through the flushing port. An o-ring seals the receiving chamber and prevents sea water from entering the receiving chamber when the male member is partially withdrawn from the female member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates in general, to hydraulic couplings, and specifically 
to hydraulic couplings used in undersea drilling and production 
applications. More particularly, the invention involves a self-flushing 
hydraulic coupling for flushing bacteria and other contaminants from the 
hydraulic lines and other subsea equipment while both members of the 
coupling remain subsea. 
2. Description of the Related Art 
Subsea hydraulic couplings are old in the art. The couplings generally 
consist of a male and female member with sealed fluid passageways 
connecting therebetween. The female member generally is a cylindrical body 
with a relative large diameter longitudinal bore at one end and a 
relatively small diameter longitudinal bore at the other. The small bore 
facilitates connections to hydraulic lines, while the large bore seals and 
slidingly engages the male member of the coupling. The male member 
includes a cylindrical portion at one end having an outer diameter 
approximately equal to the diameter of the large bore in the female member 
of the coupling. The male member also includes a connection at its other 
end to facilitate connection to hydraulic lines. When the cylindrical 
portion of the male member is inserted into the large bore of the female 
member, according to various embodiments of the device, fluid flow is 
established between the male and female members. 
The male member and female member are generally connected to opposing 
plates of a manifold and are held together by bolts or hydraulic members 
attached to the plates of the manifolds. The male member is commonly 
attached to one plate, while the female member is attached to an opposing 
plate so as to face the male member and align with it. The male member and 
female member may be attached to the manifold plates using various means, 
such as set screws or threads. Techniques for attaching the members to 
such manifold plates are well known to those skilled in the art. 
A problem with most subsea hydraulic systems used in drilling and 
production operations utilizing water and soluble oil as hydraulic fluid, 
is the stagnation and growth of bacteria, as well as the accumulation of 
other contaminants, in the hydraulic lines and other subsea equipment. 
Periodically, the hydraulic lines must be flushed out to prevent the lines 
from stopping up. Typically, the flushing operation involves special 
flushing equipment that is sent subsea and utilized manually with divers, 
or, alternatively with a special diverless system. Both the automatic and 
manual system are very costly in terms of additional equipment needed and 
time lost during the flushing operation. Typically, it is desirable to 
flush out the hydraulic line connected to one member of the hydraulic 
coupling while that member is disconnected from the other member of the 
coupling. The biodegradable flushing fluid may be expelled from the 
disconnected coupling member into the sea water surrounding the coupling. 
SUMMARY OF INVENTION 
The present invention resides in a hydraulic undersea coupling of the 
foregoing type, including male and female members for fluid communication 
therebetween such that the hydraulic lines and equipment connected to one 
of the coupling members may be flushed out while the male member is 
partially withdrawn from the female member receiving chamber. During the 
flushing operation, the male member remains in sealed relation with the 
female member as the coupling is subsea. One or more flushing ports are 
included in the female member, communicating between the receiving chamber 
and the outside surface of the female member body. Each flushing port 
includes a one way check valve, such as an o-ring, to prevent entrapping 
sea water in the receiving chamber while the male ember is partially 
withdrawn from the female member. 
The male and female member each include a poppet valve to control fluid 
flow therethrough. During the flushing operation, the poppet valve of the 
member designated for flushing remains open while the poppet valve of the 
member not designated for flushing is closed. When the male member is 
partially withdrawn from the female member receiving chamber, the poppet 
valve spring in the member not designated for flushing exerts a stronger 
force to close the poppet valve of that member. A weaker poppet valve 
spring on the member designated for flushing allows that poppet valve to 
remain open during the flushing operation. Both poppet valve noses remain 
in contact while only the poppet valve of the member designated for 
flushing is open. 
According to the present invention, to commence the flushing operation the 
leading face of the male member must pass the flushing port. The flushing 
fluid, which is under pressure, flows through the hydraulic line connected 
to the member designated for flushing, through the coupling member and 
into the receiving chamber, and out the flushing port past the o-ring 
check valve. 
The flushing ports enable the flushing operation to take place with only 
partial separation of the coupling members, and the members remain in 
sealed relation. The present invention solves the problems of additional 
equipment and time normally required for the flushing operation of a 
subsea hydraulic coupling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment of the present invention comprises a male member 
20, a female member 40 and fluid passages establishing fluid communication 
between the male member and female member when the male member is inserted 
into the female member receiving chamber 41. The fluid communication 
between the members is established when the tips 37 and 57 of the poppet 
valves 30 and 50 are mutually engaged during the connection of the body 
members. The axial movement required to connect the body members unseats 
the poppet valves and opens the bores of the body members to establish 
communication therebetween. Each poppet valve in a self-sealing coupling 
usually relies upon in part the fluid forces within the body member bore 
to maintain the poppet valve in engagement with the valve seat. 
FIG. 1 is an elevational view of a manifold 10 which is commonly used with 
undersea hydraulic couplings. The couplings 11 are generally connected to 
opposing plates of the manifold and are held together by bolts or 
hydraulic members attached to the plates. As shown in FIG. 2, the male 
member 20 is commonly attached to one plate while the female member 40 is 
attached to the second plate so as to face the male member 20 and align 
with it. 
FIG. 3 is an exploded perspective view of the coupling of the present 
invention. As shown, the main components of the coupling include a female 
member 40 and a male member 20. The female member 40 and the male member 
20 each comprise subcomponents which will be more fully described below. 
As shown in FIG. 3, according to the present invention the male member 20 
comprises a body having a handle 22, a shoulder 21 and a cylindrical outer 
wall 28. A longitudinal bore 24 extends from the handle end of the male 
member to the leading face 23 of the male member. A poppet valve 30 is 
slideably received within the longitudinal bore 24. 
The poppet valve 30 of the male member comprises a first hollow cylindrical 
body section 31 with outer dimensions corresponding to the longitudinal 
bore 24. Adjacent the first body section of the poppet valve is a second 
hollow body section 32 having apertures 33 for fluid flow therethrough 
when the poppet valve is in the open position. Adjacent the second body 
section is a conical valve face 34 which mates with valve seat 35 near the 
leading face 23 of the male member to seal off fluid flow through the male 
member. At the apex of the conical valve face 34 is a nose section 36 
extending longitudinally to tip 37. Normally the male member poppet valve 
30 is urged towards the closed position by poppet valve spring 25. The 
other end of the poppet valve spring 25 is held in place with retainer 26 
and retainer clip 27. 
The female member 40 comprises a handle end 42, a body section 43, and a 
receiving chamber 41 dimensioned to match the cylindrical outer wall 28 of 
the male member and for slideably receiving the male member therein. The 
female member further comprises a longitudinal bore 44 for slideably 
receiving a poppet valve 50. The poppet valve 50 of the female member 
comprises a first cylindrical hollow body section 51, a second hollow body 
section 52 having apertures 53 extending therethrough, and a conical valve 
face 54 which seals against valve seat 55 at one end of the female member 
bore 44. Extending from the conical valve face 54 is nose section 56 which 
terminates at tip 57. The female member poppet valve is biased into the 
closed position with a poppet valve spring 45. One end of the poppet valve 
spring 45 is anchored by retainer 46 and retainer clip 47. 
The receiving chamber of the female member includes a pair of annular 
elastomeric seals for sealing against the outer wall 28 of the male member 
during interconnection of the coupling members. Preferably, a first outer 
seal 71 is included in outer groove 70 of the receiving chamber, and an 
inner seal 73 is included within an inner groove 72 of the receiving 
chamber. As the male member is inserted into the female member receiving 
chamber, the leading face 23 of the male member first passes the outer 
seal, and then passes the inner seal when the members are fully connected. 
As can be seen in FIG. 4, the tips 37 and 57 of the male member poppet 
valve 30 and the female poppet valve 50, respectively, are mutually 
engaged before the male member is fully inserted into the female member. 
Typically, the tips are mutually engaged after the leading face 23 of the 
male member passes the outer seal 71. It also should be noted that the 
poppet valve of one of the members opens before the poppet valve of the 
other member, because of a differential between the force constant of the 
male member poppet valve spring 25 and the female member poppet valve 
spring 45. One of the poppet valve springs has a stronger force constant 
than the other poppet valve spring, so that upon initial engagement of the 
nose section tips 37 and 57, one of the poppet valves slides into the open 
position before the other poppet valve. 
The differential between the force constant of the poppet valve springs of 
each member is critical to the present invention. It is not critical, 
however, whether the male member or the female member has the stronger 
spring. In the embodiment shown in FIG. 4, the stronger spring is shown in 
the female member, which is in the closed position. The poppet valve 
spring of the male member is the weaker of the two so the male member 
poppet valve is open. Thus, in FIG. 4 the male member is connected to the 
hydraulic line designated for flushing. The flushing operation will be 
described in more detail below. 
The female receiving chamber includes one or more flushing ports 60 and 60A 
which extend between the receiving chamber 41 and the outer body 43 of the 
female member. Preferably the flushing ports are positioned between the 
inner seal 73 and the outer seal 71 of the receiving chamber. The flushing 
ports further comprise an o-ring seat 61 and an o-ring 62 which surround 
the circumference of the female member body. 
During the flushing operation, the male member is withdrawn partially from 
the female member receiving chamber so that the leading face 23 of the 
male member passes the flushing ports 60, 60A. At that time the male 
member outer wall 28 remains sealed against the outer seal 71 of the 
receiving chamber. Also during partial withdrawal the tips 37 and 57 of 
the poppet valves remain engaged. In the embodiment shown in FIG. 4, the 
poppet valve spring 45 of the female member has a stronger force constant 
so that it forces the female member poppet valve closed, while the poppet 
valve of the member which is designated for flushing remains open. 
In order to flush the hydraulic line connected to the male member while the 
members remain in sealed relation, the male member is partially withdrawn 
from the female member until the leading face 23 passes both the inner 
seal 73 and the flushing ports 60 and 60A. At this point the poppet valve 
in the female member has closed. Of course the springs could be reversed 
if the female member were designated for flushing rather than the male 
member. 
As shown in FIG. 4, wherein the male member is connected to the hydraulic 
line to be flushed, the male poppet valve remains open so that flushing 
fluid can be introduced through the corresponding hydraulic line. The 
flushing fluid is biodegradable, so that it is forced out under pressure 
through the hydraulic line, through the male member, into the receiving 
chamber, and out the flushing ports 60 and 60A past the o-ring 62. 
When flushing is completed, the flow of flushing fluid and pressure is 
stopped. After flushing is stopped, the o-ring check valve closes against 
the o-ring seat 61 due to hydraulic pressure of the outside sea water. The 
o-ring seal thus prevents entrapment of sea water in the receiving chamber 
adjacent the leading face 23 of the male member. After flushing, the male 
member then may be fully inserted to reestablish fluid flow between the 
male and female members, as shown in FIG. 5. 
The advantages of the present invention include elimination of the need for 
additional equipment during flushing of the hydraulic lines connected to 
one of the members of a subsea hydraulic coupling. According to the 
present invention, the hydraulic lines connected to one member may be 
flushed out while the coupling remains intact and sealed. The member not 
designated for flushing is sealed while the flushing operation takes 
place. 
Another advantage of the present invention is elimination of time lost 
while the flushing operation progresses. In order to flush a subsea 
hydraulic line according to the present invention, the members are 
partially disconnected while remaining in sealed relation to one another. 
Thus, because flushing will cause only a minimal delay, the hydraulic 
lines and equipment can be better maintained without being stopped up by 
bacteria and other contaminants. 
Although variations in the embodiment of the present invention may not each 
realize all of the advantages of the invention, certain features may 
become more important than others in various applications of the device. 
The invention, accordingly, should be understood to be limited only by the 
scope of the appended claims.