Rotatable pipe coupling structure

The specification describes a rotatable multiple pipe coupling structure employing a labyrinth seal between each stationary pipe and its respective rotatable pipe. Because of no protruding parts from inner pipes into the channels, there will be minimized turbulence in the fluids to be transferred through the rotatable multiple pipe coupling structure. There is also described a rotatable pipe coupling structure having a stationary pipe and a corresponding rotatable pipe. The pipes are rotatably sealed with a labyrinth seal. The coupling structures according to this invention may be further provided with a driving shaft longitudinally and centrally extending therethrough. The coupling structures of this invention are applicable for a revolving floor such as tower restaurants, for changing the surface area of vehicle tires while in motion, for moving cranes, for remote handling of materials such as radio-active materials, for gun turrets, helicopters, heavy mining machinery, and wherever there is required to transfer at least one fluid from a stationary element to a rotatable element.

This invention relates to a pipe coupling structure and in particular to a 
rotatable pipe coupling structure adapted to transfer a fluid under 
pressure between a stationary conduit and a rotatable conduit. This 
invention also relates to a rotatable multiple pipe coupling structure 
adapted to separately transfer a plurality of fluid under pressure between 
stationary conduits and the corresponding rotatable conduits wherein each 
stationary conduit and the corresponding rotatable conduit are adapted for 
a different fluid. 
There have been known many rotatable multiple pipe coupling structures. 
U.S. Pat. No. 464,707 issued on Dec. 8, 1891 to Burns discloses a 
cylinder-in-sleeve or telescoping tubular connector for a plurality of 
isolated fluids. U.S. Pat. No. 2,825,463 issued Mar. 4, 1958 to Thomas 
discloses another cylinder-in-sleeve type arrangement. U.S. Pat. No. 
485,596 issued on Nov. 1, 1892 to Morgan discloses a concentric steam 
joint casing provided with a pair of concentric stationary chambers and 
matching concentric rotatable chambers. Each chamber is provided with an 
opening. Canadian Pat. No. 919,212 issued Jan. 16, 1973 to Maurer et al 
discloses a quick disconnect rotary joint comprising a pair of concentric 
cylindrical channels formed by an inner stationary cylinder and the 
combination of an outer stationary cylinder and an outer rotatable 
cylinder. The outer cylinders are detachably and rotatably connected 
together by extending the proximal end wall of the stationary outer 
cylinder over the proximal end wall of the rotatable outer cylinder, 
forming an annular recess in the outer surface of the end wall of the 
rotatable outer cylinder and a matching annular recess in the inner 
surface of thus extended end wall of the stationary outer cylinder and 
disposing an O-ring within the cavity formed by the recesses. 
The rotatable multiple coupling according to each of the Burns, Thomas and 
Morgan patents includes highly complicated flow paths for liquids to be 
transferred between the stationary conduits and their corresponding 
rotatable conduits. Such flow paths are considered to be undesirable for 
transferring fluids therethrough because they cause considerable 
turbulence of the fluids therein. This drawback becomes more apparent when 
fluids are transferred under pressure. Such turbulence will result in 
reduction of flowing velocity which may be compensated for by increasing 
the pressure. However, as easily envisaged, it is necessary to employ a 
rotatable seal with a very high sealing ability for such 
highly-pressurized fluid which can be a very real problem. The rotatable 
multiple coupling of the Morgan patent, furthermore, is limited to 
oscillation and does not permit full rotation. The quick disconnect rotary 
joint of the Maurer patent also uses complicated flow paths, especially 
for the outer conduit. The rotatable seal of the Maurer patent may be 
useable for an outermost stationary pipe and its corresponding outermost 
rotatable pipe. However, it is inadequate to use for an inner stationary 
pipe and its corresponding inner rotatable pipe as the seal has some 
elements projecting from the outer surfaces of the pipes at the place 
where they meet. Such projection causes undesired turbulence in the fluid 
being transferred therealong. 
The object of this invention is to provide a rotatable pipe coupled 
structure adapted to transfer a fluid under pressure between a stationary 
conduit and a rotatable conduit, while minimizing undesired turbulence of 
the fluid. 
Another object of this invention is to provide a rotatable multiple pipe 
coupling structure adapted to separately transfer a plurality of fluid 
under pressure between stationary conduits and the corresponding rotatable 
conduits, while minimizing undesired turbulence of fluid. 
A further object of this invention is to provide a rotatable multiple 
coupling structure as described above employing labyrinth seals. 
Still further object of this invention is to provide a rotatable multiple 
pipe coupling structure as described above having means for driving the 
rotatable element to which said rotatable conduits are secured. 
Such a rotatable multiple pipe coupling structure with a driving shaft 
about which a plurality of pipes are concentrically provided may be 
applied, for example, for a revolving floor such as tower restaurants, for 
changing the surface area of vehicle tires while in motion, for moving 
cranes, for remote handling of materials such as radio-active materials, 
for gun turrets; helicopters, heavy mining machinery, and wherever there 
is required to transfer at least one fluid from a stationary element to a 
rotatable element. 
In one aspect of this invention there is provided a rotatable pipe coupling 
structure adapted to transfer a fluid between a stationary conduit and a 
rotatable conduit, comprising a combination of a stationary pipe and a 
rotatable pipe rotatably sealed together at the proximal end surfaces 
thereof by means of a labyrinth seal, said pipes being rotatably coupled 
at the proximal wall surfaces thereof with an annular hugger ring. 
In another aspect of the invention there is provided a rotatable multiple 
pipe coupling structure separately comprising a combination of a 
stationary outer pipe and a rotatable outer pipe rotatably sealed together 
at the proximal end surface thereof by means of a labyrinth seal, said 
outer pipes being rotatably coupled at the proximal end wall surfaces 
thereof with an annular hugger ring; at least one combination of a 
stationary inner pipe and a rotatable inner pipe rotatably sealed together 
at the proximal end surfaces thereof by forming at least one annular 
groove in the proximal end surface of one of the inner pipes and a 
matching annular groove in the proximal end surface of the other inner 
pipe and by slidably disposing an annular sealing ring within the annular 
cavity formed with the grooves; said stationary outer and inner pipes 
being secured with a stationary wall at the distal ends thereof and the 
rotatable outer and inner pipes being secured at the distal ends thereof 
with a rotatable wall; and the stationary and rotatable walls being 
provided therethrough with at least one opening communicating with each of 
the passages formed with the pipes. 
In still another aspect of this invention, there is provided such a 
rotatable multiple pipe coupling structure as described above wherein the 
structure further comprises a pair of shaft openings. Each of the shaft 
openings is provided through each of the stationary and rotatable walls. 
The pair of shaft openings communicate with an innermost passage formed 
within the innermost stationary and rotatable pipes. The structure is 
further provided with a shaft extending through the innermost passage and 
the pair of shaft openings. The shaft is adapted to rotate the rotatable 
pipes, wall and conduits. In a preferred embodiment, the rotatable wall is 
mounted on a chassis in such a manner that any shock which may be exerted 
onto the rotatable element may be transmitted therebetween via the shaft 
and the chassis without exerting stress onto the rotatable sealing 
structure. 
The advantages derived from the present invention are numerous. The outer 
stationary pipe and the outer rotatable pipe are rotatably sealed by the 
labyrinth seals and they are further rotatably coupled with a hugger ring. 
The inner stationary pipes and the corresponding inner rotatable pipes are 
also rotatably sealed together by forming a rather complicated and longer 
path between the proximal ends of the pipes. Because no part protrudes 
from the proximal ends of the pipes, there is substantially eliminated 
undesired turbulence of fluid at the place where both the stationary and 
rotatable pipes are rotatably sealed.

In FIG. 1 concentric stationary pipes 1, 2, 3, 4, 5 are fixedly secured to 
the chassis 6. The pipe 1 is the stationary outer pipe and the other 
stationary pipes are inner pipes. The concentric separate channels formed 
by the concentric stationary channels communicate with the stationary 
conduits 10, 11, 12, 13. The rotatable outer pipe 14 encloses 
concentrically rotatable inner pipes (not shown) which engage the 
stationary inner pipes 2, 3, 4, 5 respectively. The concentric rotatable 
outer and inner pipes are secured to the rotatable wall 15 through which 
rotatable conduits 20, 21, 22, 23 are provided. The rotatable conduits 
respectively communicate with the concentric rotatable channels formed by 
the concentric rotatable inner and outer pipes. There is provided through 
the innermost pipes a shaft 24 which is adapted to be driven by the pulley 
25. Instead of the pulley, a conventional force transmission mechanism can 
be used. For example, a ring gear may be fixedly secured about the shaft 
24 and said ring gear can be driven by a pinion which is driven by any 
suitable driving means. Alternatively the shaft 24 may be driven by a 
motor mounted on the rotatable element including the rotatable pipes, 
rotatable conduits 20, 21, 22, 23 and rotatable end wall 15. 
The stationary conduits and the rotatable conduits may respectively be used 
as supply conduits for fluid under pressure such as water and hydraulic 
fluid and as receiving conduits therefor. It is possible to employ more or 
less than four inner pipes as illustrated. It is also possible to employ 
one concentric channel for a fluid and the adjacent concentric channels as 
vent channels to prevent the fluid from being mixed with different fluids 
which are transferred through the adjacent channels. When fluids under 
pressure are transferred through the rotatable multiple coupling 
structure, the vent channels may be filled with a pressurized fluid which 
is inert to the fluids to be transferred. 
In FIGS. 2A and 2B, there are shown coupling and sealing structures for the 
outer stationary pipe 1 and the outer rotatable pipe 14. In the structure 
shown in FIG. 2A, the proximal end walls of both outer pipes are provided 
with annular collars 30, 31. A male hugger ring 32 is secured to the outer 
wall of the outer rotatable pipe, adjacent to the distal wall of the 
collar 31. A female hugger ring 33 is rotatably provided over the collar 
30 and is engaged with the male hugger ring 32. The hugger rings 32, 33 
are secured together by means of a lock screw 34. The proximal end surface 
of the stationary outer pipe is precision-worked to provide an annular 
groove 35 and a concentric annular tooth 36. The proximal end surface of 
the rotatable outer pipe is also precision-worked to form an annular tooth 
37 and a concentric annular groove 38 which rotatably and sealingly engage 
the groove 35 and the tooth 36 of the stationary outer pipe, thereby 
forming a labyrinth seal between the outer pipes. When a highly 
pressurized fluid is transferred through the channel formed by the outer 
pipes and the adjacent inner pipes, the sealing tends to open. This will, 
however, be compensated by the hugger ring structure as the sealing 
between the hugger ring 33 and the collar 30 at the distal wall of the 
collar 30 will be enhanced. Another type of sealing and coupling structure 
for the outer stationary and rotatable pipes is illustrated in FIG. 2B. As 
in the embodiment of FIG. 2A, the proximal end walls of both outer pipes 
are provided with annular collars 40 and 41. A female hugger ring 42 and a 
male hugger ring 43 are engaged together and secured together by means of 
a lock screw 44. The hugger rings rotatably embrace the collars 40 and 41. 
There are provided a pair of spring-loaded ball bearing rings 45, 45 
between the collars and the hugger rings at the distal wall of each of the 
collars. The proximal end of the rotatable outer pipe 14 is provided with 
an annular groove 46 and a matching annular concentric groove 47 is formed 
in the proximal end of the stationary outer pipe 1. Both grooves 46, 47 
form an annular cavity within which a sealing ring 48 is slidably 
disposed. 
In FIG. 3, there is illustrated a sealing structure for the stationary 
inner pipe 2 and the corresponding rotatable inner pipe 50. The same 
structures can be used for the other stationary inner pipes 3, 4, 5 and 
the corresponding rotatable inner pipes. The proximal end of the 
stationary inner pipe 2 is provided with three spaced concentric annular 
grooves 51, 52, 53 which respectively correspond to the matching grooves 
54, 55, 56 in the proximal end of the rotatable inner pipe 50. The grooves 
51, 54 form an outermost annular cavity within which a sealing ring 48 is 
slidably disposed. The grooves 53, 56 form an innermost annular cavity 
within which a sealing ring 48 is slidably disposed. The central annular 
cavity formed by the grooves 52 and 55 may be used as a collector recess 
which communicates through vent channels 57 and 58 with a vent opening 
provided through each of the chassis 6 and the rotatable wall 15, where 
any leakage is either recovered or discarded. When a high degree of 
sealing is not required, it may be possible to employ only one groove in 
each of the proximal ends of the inner pipes 2, 50. On the other hand, 
when an extremely high degree of sealing is required, it is preferred to 
employ more than two sealing rings, and each adjacent two rings having a 
collector recess therebetween. It may be preferred to have a small amount 
of leakage into each sealing arrangement as such leakage may serve as 
lubricant for the sealing arrangement. 
Referring to FIG. 4, the stationary pipes are terminated in a stationary 
end wall 60. The stationary end wall 60 is provided with at least two 
claws 61 extending outwardly from the peripheral edge of the end wall 61. 
The claws 61 engage their respective posts 62 which extend perpendicularly 
from the chassis 6. Each claw and its respective post must have 
longitudinal tolerance greater than that between a main bearing of the 
shaft (not shown) and the chassis 6, thereby allowing any shock to the 
rotary element which is rigidly fastened to the shaft to be transmitted to 
the chassis via the shaft and main bearing without exerting stress onto 
the coupling arrangement between the stationary pipes and the rotatable 
pipes. The same arrangement may be used for the rotatable pipes. 
The stationary pipes and rotatable pipes of the present invention may be 
made from cast iron or forged steel depending upon pressures of the fluids 
to be transferred and heat to be generated. Such cast iron or forged steel 
must pertain a very small co-efficient of expansion against pressure 
and/or temperature. Furthermore, design of sealing arrangement must be 
determined not only from the viewpoint of rotatable sealing but also from 
the viewpoint of heat and/or pressure expansion or shrinkage of the 
sealing arrangement. It is also obvious that any additional sealing and/or 
lubricating elements can be employed in conjunction with the hugger ring 
and the labyrinth seals.