Apparatus for fastening flanged tubular members

A method and apparatus for aligning and fastening open ended tubular members, such as pipes, tanks, and other cylindrically shaped fluid enclosures, which have radially outwardly protruding flanges extending around the circumference of the open ends. The flanges have flat mating faces and tapered back sides defining conical surfaces which converge radially outwardly when the flanges of two tubular members are abutted. The fastening device comprises a ring, a plurality of rotatable and radially movable clamping spools retained on the ring, and a like plurality of bolts on the ring for moving the clamping spools radially inward. The rotatable clamping spools have a cylindrical shank and rim segments at the shank ends which extend around only a portion of the shank circumference. The rim segments, which define opposing clamping faces, are dimensioned so as to accommodate the shape of the flange back sides and to apply axial clamping forces to the mated flanges when the spools are forced radially inward by the bolts. Any three generally equally spaced apart clamping spools may be rotated so their respective rim segments point radially outward and may then be forced radially inward so that the shanks of the three spools initially axially align the abutted flanges prior to clamping.

BACKGROUND OF THE INVENTION 
This invention relates to closure devices and fastening means for pipes, 
tanks and various other tubular shaped fluid enclosures, which are 
generally subjected to high internal pressure. 
A common device for fastening such tubular members to one another empolys a 
plurality of bolts which pass through radially extending flat flanges 
provided on the ends of the tubular members. One problem inherent in such 
a device is that it is often difficult to accurately align the end flanges 
with one another in order that the bolts may be placed through the holes. 
This problem is accentuated when relatively heavy tubular members, such as 
pipeline segments, are required to be secured to one another. A further 
disadvantage of the use of bolts to secure the flat end flanges is that 
due to the diameter of the bolt head and the need for engaging the bolt 
heads with wrenches that fit over them the flanges must extend a 
considerable distance from the pipe or vessel wall. Consequently, the 
axial forces produced by the bolts are applied at a substantial distance 
from the pipe or vessel wall, thereby resulting in bending moments and 
adverse stresses about the ends of the pipe or vessel segments. 
Most recently, tubular members have been secured to one another with 
radially protruding, tapered end flanges extending around the 
circumference of the open ends of the tubular members. Like the flat 
flanges, these flanges also have flat mating faces. However, the back 
sides of the flanges are tapered, i.e. they define a conical surface which 
diverges in a radially outward direction towards the open end of the 
tubular member. Thus when the mating faces of two pipes or vessels are 
abutted against one another, the backs of the mated flanges converge 
radially outwardly from the pipes or vessels. A yoke or split ring device 
having a groove shaped so as to generally match the mated flanges is then 
used to clamp the pipe or vessel segments together. The split ring 
comprises two semi-circular segments. The two segments of the ring are 
placed over the mated flanges and the ends of the two ring segments are 
secured together with bolts which are oriented tangentially to the 
completed ring. As the bolts are tightened the grooves of the ring apply 
axial clamping forces to the tapered back sides of the mated flanges. A 
split ring fastening device of this type is described in U.S. Pat. No. 
3,077,360. 
Although such an arrangement is a substantial improvement over the earlier 
discussed bolted flange connection, it has several disadvantages. The 
flanges are difficult to align, especially when the pipe or vessel 
segments are heavy, e.g. when the segments are adapted for high pressure 
application. Because the flanges are machined in various sizes and shapes, 
a separate split ring is required to accommodate each specific flange 
size. Additionally, the tapered back sides of the flanges have various 
irregularities around their circumference either because of normal 
machining tolerances or because of galling and wear caused by frequent 
use. Accordingly, the axial thickness of the mated flanges may vary 
considerably around the circumference. Thus when the split ring segments 
are attached and bolted together, the axial clamping forces are not always 
equally distributed around the circumference of the mated flanges and 
adverse bending moments and stresses result. A further disadvantage of the 
split ring connection occurs because the ring normally contacts the 
flanges around the entire circumference, and thus the ring is often 
extremely difficult to remove because of rust or corrosion which may have 
developed after exposure to the atmosphere for an extended time period. 
SUMMARY OF THE INVENTION 
The present invention provides a method and apparatus for fastening 
generally open ended tubular members, such as pipes, tanks and vessels, 
which eliminates at least some of the disadvantages inherent in prior art 
connectors. 
The tubular members which are fastened together by the invention include 
pipes, tanks, pressure vessels, cover plates and any type of cylindrically 
shaped fluid enclosure which is open ended and has a radially outwardly 
protruding flange extending around its open end. These types of tubular 
members, hereinafter collectively referred to as "pipes", are fastened to 
one another at their respective open ends by applying axial forces to 
these protruding flanges so that the pipes are thus held together at their 
open ends. 
A typical flange is either rigidly secured to the open end of the pipe, as 
by a weld, or is an integral part of the pipe, and extends radially 
outward from the pipe wall over the entire pipe circumference. The flange 
has a flat mating face oriented axially outward from the open pipe end for 
abutting with a corresponding mating face of another pipe and a back side 
pointing generally in the opposite direction of the mating face. The back 
side is either flat and thus generally parallel with the mating face, or, 
preferably, it is tapered so as to define a conical surface which diverges 
radially outward in the direction of the open pipe end. The flange has a 
radially outermost periphery which is between the mating face and back 
side and which defines the axial thickness of the flange. 
The present invention provides a connector for two pipes of the above 
discussed type and specifically of the type having flanges with tapered 
back sides. The connector comprises a ring having an inner diameter 
greater than the outer diameter of the peripheries of the flanges. The 
open ends of the two pipes are brought together so that the mating faces 
of their respective flanges abut. The ring is placed over the mated pipes 
and axially aligned with the plane of the abutted mating faces of the 
flanges. Provided on the ring and spaced circumferentially around the ring 
are a plurality of rotatable clamping members which are movable in a 
radial direction. A plurality of radially oriented bolts, each associated 
with a respective clamping member, are also provided on the ring, and 
serve to move the clamping members radially inward. 
Each of the clamping members is normally defined by a rotatable spool which 
has a generally cylindrical central shank or hub and rims on the ends of 
the central shank. The rims define at least one pair of opposing clamping 
faces which diverge outwardly from the shank at generally the same angle 
at which the tapered back sides of the flanges diverge from the wall of 
the pipe. Further, the distance between the opposing clamping faces is 
sufficient to permit the rims of the spool to overlap the back sides of 
the mated flanges. The rims extend around only a portion of the 
circumference of the shank. Thus, that portion of the rim perimeters which 
do not have clamping faces essentially define planar surfaces which are 
tangential to the shank. At the point of tangency, the shank effectively 
extends the entire axial length of the spool. 
After the ring is placed over the pipes whose open ends are abutted, any 
three of the spools, selected at approximately 120 degree increments 
around the ring so as to define a generally triangular pattern, are 
rotated so that the clamping faces are oriented radially outward. These 
three spools are then moved radially inward by tightening their respective 
bolts so that the shanks force the two flange peripheries and thereby the 
two pipes to axially align with one another. 
The remaining spools are then rotated so that a proper sized pair of 
clamping faces, selected to accommodate the particular size of flanges, is 
oriented radially inward. These remaining spools are then moved radially 
inward by tightening their respective bolts. Tightening the bolts moves 
the spools towards the mated flanges so that the clamping faces on the 
spools overlap the back sides of the mated flanges. Once the clamping 
faces overlap the back sides of the mated flanges, an additional radial 
force is applied by further tightening the bolts. These radial forces 
applied to the spools are transferred from the clamping faces of the 
spools to the back sides of the flanges. Because the back sides of the 
mated flanges are tapered so that they converge radially outward, the 
radial forces applied by the bolts to the clamping faces of the spools are 
translated into axial forces which clamp the pipe ends together. 
The first three spools used to axially align the pipes are withdrawn 
radially outward by loosening their respective bolts. These three spools 
are rotated so that the proper sized pair of clamping faces are oriented 
radially inward and the three spools are then moved radially inward by 
their respective bolts in the manner discussed, thereby completing the 
pipe connecting process. 
When the connector is to be used to clamp pipes having flanges with flat 
back sides, wedge segments are secured to the flat back sides to thereby 
convert them into tapered back sides. 
Irregularities in flange thickness because of galling or machining 
tolerances do not create a problem with the present invention since each 
of the spools is independently movable in a radial direction. Thus for 
example, if the flanges are irregularly thin at a point where a particular 
pair of clamping faces overlaps the flanges the spool is merely moved 
further inward with an additional radial force until the clamping faces 
apply sufficient axial clamping forces to the back sides of the mated 
flanges. 
Furthermore, since the total bearing surface contacting the flanges is 
relatively minimal with the present invention, as compared to the prior 
art split ring, there is much less likelihood that the clamping faces will 
become stuck to the back sides of the flanges by rust or corrosion. To 
further alleviate this problem, the spools are constructed of corrosion 
resistant material and grooves are cut on the back sides of the flanges to 
define a "waffle" pattern of depressions in which lubricating grease may 
be stored. The durability and strength of the connector are increased by 
constructing the spools of high strength material, such as carbon steel. 
It should be apparent that the present invention provides a connector for 
pipes which not only securely clamps open ended pipes to one another, but 
also conveniently axially aligns those pipes prior to fastening. The 
invention provides a fastening device which is capable of accommodating 
various sizes and shapes of flanges as well as flanges having surface 
irregularities. The present invention provides a fastening means which may 
be quickly disconnected, even after exposure to the atmosphere for an 
extended time period. 
The novel features which are believed to be characteristic of the 
invention, together with objects and advantages thereof, will be better 
understood from the following description considered in connection with 
the accompanying drawings in which preferred embodiments of the invention 
are illustrated by way of example. It is to be expressly understood, 
however, that the drawings are for the purpose of illustration and 
description only and are not intended as a definition of the limits of the 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring first to FIGS. 1 and 2, two pipes 10 and 12 to be secured and 
sealed to each other are fitted with circumferential end flanges 14 and 16 
which have flat mating surfaces 18 and 20, one of which may include an "O" 
ring 22 for sealing the flanges to each other. Back sides 24 and 26 of the 
flanges face away from each other and are tapered so that they converge in 
a radially outward direction, normally in the plane of the mating faces 18 
and 20. Thus, the back sides of the flanges define conical surfaces. The 
flanges and therewith the pipes are secured to each other in accordance 
with the present invention with connector 30 defined by a ring 32 having 
an inner diameter which exceeds the outer diameter of flanges 14 and 16 
and which is placed thereover. Attached to an inside of the ring are a 
multiplicity of clamping spools 34 which are disposed between the 
peripheries 36 and 38 of pipe flanges 14 and 16 and the ring. Each spool 
is defined by a generally cylindrical shank 56 and pair of spaced apart 
rims 58 and 60 which protrude radially from the shank. The rims define 
opposing clamping faces 68 and 70 which have a taper complementary to that 
of the pipe flange back sides 24 and 26. 
In use, the ring together with the spools retained thereto is placed over 
the flanges 14 and 16 so that the tapered clamping faces 68 and 70 of the 
spools are disposed radially outward of the flange peripheries 36 and 38. 
Thereafter the spools are moved so that the tapered clamping faces overlap 
the tapered flange back sides 24 and 26 until the clamping faces and the 
flange back sides are in mutual engagement. Additional radially inward 
acting forces are applied to each spool which generate axial force 
components between the clamping faces and the flange back sides 24 and 26 
which bias the flanges and force the pipes towards each other to secure 
the flange mating faces 18 and 20 and establish a seal therebetween. A 
sufficient radial force is applied to each of the spools until the 
combined generated axial force exceeds the force generated by the pressure 
within the enclosure. 
Referring now to FIGS. 1 through 4, ring 32 may be constructed as a unitary 
ring or two rings halves 40 and 42. On its inner side, the ring includes a 
multiplicity of generally semi-circular cutouts or recesses 44 for 
receiving and nesting the multiplicity of clamping spools 34. As is best 
shown in FIG. 3, the ring 32 has an axial thickness about equal to the 
axial length of the spools and includes cutouts 44 to receive the spools. 
Further, the ring includes a multiplicity of radially oriented threaded 
holes 45 for receiving bolts 46 which have heads 48 accessible from the 
outer periphery of the ring and another end 50 which extends into the 
corresponding ring cutout 44. Further, spring clips 52 are secured, e.g. 
bolted, to the ring between adjacent cutouts. Each spring clip 52 has a 
sufficient length so that its ends extend into the adjoining cutouts. 
A typical clamping spool 54 is illustrated in FIGS. 2 and 3. The central 
shank or hub portion 56 has a diameter smaller than the circumferential 
width of the cutouts so that the shank portion of the clamping spool may 
reside within the cutout 44. The clamping spool 54 comprises in addition 
to the central shank 56, rim portions 58 and 60 at opposite ends of the 
shank. The perimeter of the rims of the spool 54 extend generally around 
an arc of less than 360.degree. so that at least one portion of each rim 
perimeter is a generally flat surface, such as surfaces 62 and 64. The 
flat surfaces 62 and 64 of the rims are tangential to the shank so that 
there exists a straight edge 66 which extends the entire axial length of 
the spool. The rims 58 and 60 of the clamping spool 54 defind opposing 
clamping faces 68 and 70 which diverge radially outward from the shank 56 
and which are tapered complementary to the flange back sides 24 and 26. 
The clamping spool 54 has a bolt head 59 secured thereto to facilitate 
rotation of the clamping spool within the cutout. In order to improve the 
durability and strength of the connector, especially when it is used to 
fasten pipes which must be frequently and disconnected, the clamping 
spools are preferably constructed of carbon steel. 
Connector 32 is assembled as follows. The spools 34 are placed in their 
respective cutouts on the ring by nesting the spool shank of each spool in 
the assigned cutout. When the shank is fully disposed within the cutout 
the ends of the two spring clips which protrude into the particular cutout 
bias the shank and therewith the spool as a whole in a radially outward 
direction against the semi-circular bottom of the cutout. In this manner 
the spools are retained to the ring, yet they can be moved radially inward 
by tightening the bolts to the desired extent. However, when the bolts are 
backed up or loosened the spring clips bias the spools back into the 
cutout. 
Connector 32 constructed in accordance with the present invention is used 
as follows. Initially all spools are rotated so the flat surfaces 62 and 
64 and therewith straight edge 66 face radially inward. It will be 
observed that with the spools so oriented both the shank 56 of the spool 
and the flat surfaces 62 and 64 are radially outward of the inner wall 74 
of the ring so that the ring can be slipped over the pipe flanges 14 and 
16 by moving the connector in an axial direction along the pipes. 
Next the pipe flanges are axially aligned by tightening at least three 
bolts which are equally spaced around the ring, e.g. by approximately 
120.degree., so as to produce generally triangulated forces. The 
tightening of these three bolts causes a radially inward movement of the 
three spools so that the spool shanks of those spools, and specifically 
their straight edges 66, engage the pipe flange peripheries 36 and 38. The 
tightening of these three bolts is continued until the pipe flange 
peripheries and therewith the pipes are in axial alignment. 
Next the remaining spools are rotated until the clamping faces of the 
spools, such clamping faces 68 and 70 of spool 54, are oriented radially 
inward, i.e. towards the flanges 14 and 16. These remaining spools, having 
been so oriented, are then moved radially inward by means of the bolts 
associated with each of them. The bolts are tightened so that the spools 
are moved radially inward and the clamping faces 68 and 70 overlap the 
back sides 24 and 26 of the axially aligned flanges. Because the flange 
back sides are tapered to converge radially outward, the radial forces 
produced by the bolts and transferred to the clamping faces of the spools 
generate axial forces on the back sides of the flanges. Referring to FIG. 
2, clamping faces 68 and 70 generate oppositely directed axial forces 
which urge the flanges 14 and 16 into secure contact with one another at 
their mating faces 18 and 20. Because the spools are independently movable 
by their respective bolts, each spool can be moved radially a greater or 
lesser distance than corresponding spools, depending upon the axial 
thickness of the flanges and surface irregularities of the flange back 
sides at the point where the clamping faces overlap the flange back sides. 
After the remaining spools have been moved radially inward to clamp the 
flanges, the first three clamping spools which were used to align the 
pipes are withdrawn radially outward. This is accomplished by loosening 
the bolts associated with the three spools, thereby permitting the spring 
clips associated with those spools to return the spools radially outward 
within their cutouts. These three spools are then rotated until the 
clamping faces are pointed toward the flanges, after which the three bolts 
are again tightened, thus moving the three clamping spools towards the 
flanges to complete the clamping process. 
As a final step, a torque wrench may be used to assure that equal radial 
forces are applied to the spools, thereby assuring that generally equal 
axial clamping forces are applied around the circumference of the mated 
flanges. Thus adverse bending moments and stresses about the ends of the 
pipes are avoided. 
When it is desired to remove the connector, all of the bolts are backed 
off. The spring clips 52 secured to the radially inner wall 74 of the ring 
32 intermediate adjacent cutouts 44 now bias the spools radially outward 
until the shanks rest in the semi-circular bottoms of the cutouts. Each of 
the spools is then rotated, e.g. by using a wrench to grip the bolt head 
59 on the clamping spool, until flat surfaces 62 and 64 of the clamping 
spools are again oriented radially inward. With the spools in such an 
arrangement and recessed within the cutouts, the connector may be moved 
axially away from the pipe flanges 14 and 16 without obstruction. 
The simplest construction of the connector is a unitary ring. Since the 
spools are rotatable so that the rims 58 and 60 may be oriented radially 
outwardly, and since the spool shanks 56 may be made to reside against the 
semi-circular bottoms of the cutouts 44, the single-piece ring is easily 
slipped over the flanges 14 and 16. An alternative construction of the 
ring 32 is as a split ring comprising two semi-circular ring halves 40 and 
42 which are hingedly connected. This embodiment of the connector is 
especially suitable for use with long pipes since the two ring halves 40 
and 42 may be opened about the hinge and then closed directly over the 
flanges 14 and 16, without the necessity of slipping the connector over 
one end of a pipe. The ring 32 is constructed of two ring halves 40 and 
42, as shown in FIG. 1. In such a construction, first ends of the ring 
halves 40 and 42 are hingedly connected with a pin 76 while the other ends 
of the ring halves are releasably secured to each other with a bolt 78, a 
clamp (not shown), or the like. In this embodiment the ring is used by 
opening the two halves, placing them over the pipe flanges and thereafter 
closing them by pivoting the halves about pin 76 and bolting the other 
ends of the ring halves to each other. The further steps of aligning the 
pipe ends and securing them to each other with the clamping spools is as 
above described. 
Because the connector may be subjected to the atmosphere for an extended 
time period, it is desirable to provide means for preventing the corrosion 
of the connector, and especially the movable parts, such as the spools and 
bolts. Thus each of the bolts 46 has associated with it a sealed space 80 
between the bolt head 48 and the threaded portion of the bolt for 
retaining a lubricant. Referring to FIG. 4, the space 80 contains a 
lubricant such as grease. The lubricant is sealed therein by means of an 
"O" ring 82 which is secured to the bolt head 48. The "O" ring seal and 
the grease prevent entry of water and other contamiants into the threaded 
hole, thereby preventing the bolts from becoming stuck within the holes. 
When the bolts are loosened the threads of the bolts will pick up a 
portion of the grease or lubricant in the space and carry that grease back 
into the threaded holes of the ring when the bolts are subsequently 
tightened. 
While the invention as thus described comprises clamping spools which have 
opposing clamping faces separated by a constant distance around the entire 
rim perimeter and in which the taper of these opposing clamping faces is 
also relatively constant, other embodiments of the invention permit the 
connector to accommodate flanges of varying size and thickness. 
In one such embodiment a clamping spool 84 has three pairs of opposing 
clamping faces arranged in sectors around the rim perimeters, as shown in 
FIG. 5. Each pair of clamping faces, such as opposing clamping faces 86 
and 88, are machined in such a manner so as to accommodate pipe flanges of 
a particular axial thickness. The sector adjacent the clamping faces 86 
and 88, namely the sector comprising clamping faces 90 and 92, is capable 
of accommodating flanges thicker than those for which faces 86 and 88 are 
designed. Similarly, at the next adjacent sector, the rims of spool 84 
define opposing clamping faces 94 and 96 which are capable of 
accommodating pipe flanges even thicker than those for which the clamping 
faces 90 and 92 are designed. The spool 84 is thus capable of accomodating 
three different thicknesses of flanges. While the taper of all of the six 
clamping faces of spool 84 are shown in FIG. 5 as diverging from the spool 
shank at the same angle, it should be apparent that the clamping faces 
could diverge at any desired angle so as to accommodate flange back sides 
of different angular tapers. By providing a plurality of clamping spools 
such as spool 84 on the ring, a single ring is thus capable of clamping 
flanges of different axial thickness and back side angular taper. While 
three specific pairs of clamping faces are shown on spool 84, more or less 
than three pairs of clamping faces could be provided as desired. If the 
connector 32 is provided with a multiplicity of spools, such as spool 84, 
it operates in generally the same manner as above described. Prior to 
moving the spools radially inward for clamping the flanges, however, the 
spools must be rotated so that the proper rim sector, and thus the proper 
pair of clamping faces, is oriented toward the flanges. 
Referring to FIG. 6, another embodiment of the invention comprises a 
tapered spool 98 in which the rims at the opposite ends of the shank 
define opposing clamping faces which vary in axial separation with 
position on the rim perimeter. The tapered spool 98 has rims 100 and 102 
which define opposing clamping faces 104 and 106. The tapered spool 98 
provides continuous opposing clamping faces 104 and 106 which gradually 
change in axial separation with the angular location on the perimeter of 
the spool. The tapered spool is preferably designed so that the clamping 
faces 104 and 106 diverge from the shank at the same angle regardless of 
the position on the shank perimeter where that angle is measured. Thus the 
only variation with the clamping faces is the axial distance between them. 
Such a tapered spool is designed to accommodate flanges of one specific 
back side angular taper but different axial thicknesses. When the 
connector is provided with a multiplicity of tapered clamping spools, such 
as spool 98. the operation of the connector is essentially as above 
described. However, prior to moving the tapered spools radially inward, 
the spools are rotated so that the portion of the rim perimeters oriented 
towards the flanges is that portion where the clamping faces are axially 
separated by a distance generally equal to the axial thickness of the 
mated flanges. 
The invention as thus described and shown in the drawings is directed to 
clamping pipes, tanks and vessels having flanges with tapered back sides, 
such as back sides 24 and 26. With only slight modifications the present 
invention is also capable of clamping pipes having flanges with flat back 
sides. Referring to FIG. 8, the clamping of pipes having flanges with flat 
back sides 108 and 110 is accomplished by providing wedge segments 112 and 
114 for the respective flat back sides. The wedges 112 and 114, which are 
angularly shaped so as to complement the shape of the opposing clamping 
faces of the spools, are rigidly secured, e.g. welded, to the flat flange 
back sides at points around the circumference where the spools are to 
overlap the mated flanges. Wedge 112 and 114 are required for each 
clamping spool of the connector. The wedges are angularly spaced around 
the flange circumference the same as the angular spacing of the spools 34 
on the ring 32. The use of the connector for clamping flat flanges with 
wedges 112 and 114 secured to the back sides is as above described, with 
one exception. After the connector has been placed over the flanges and 
axially located so as to lie generally in the plane of the mating faces 
111 and 113, the connector is rotated until each of the clamping spools is 
angularly aligned with a corresponding pair of wedges. 
The connector with the multiplicity of clamping spools retained thereon 
provides axial clamping forces to the flanges at a discrete number of 
points around the circumference of the flanges, i.e. at those specific 
points where the clamping faces of the spools overlap the back sides of 
the flanges. Accordingly, the amount of total clamping surface contacting 
the back sides of the mated flanges is minimized, thereby reducing the 
likelihood that the clamping spools and thereby the ring will become stuck 
to the flanges because of rust or corrosion. To further reduce this 
likelihood grooves may be cut in the flange back sides in an intersecting 
pattern and lubricant placed in the grooves prior to clamping. Referring 
to FIG. 7, the lubricant is retained in the intersecting grooves 116 and 
will be generally permanently retained therein when the flange back sides 
are overlapped by the clamping faces of the spools. In order to further 
prevent corrosion and to increase the durability of the connector, the 
spools may be constructed of high-strength material such as carbon steel, 
and may be made corrosion resistant. 
While the present invention has thus far been described in use with pipes, 
such as pipes 10 and 12, the connector may be adapted for use with any 
type of vessel, such as tanks or fluid enclosures having removable covers 
in which the cover is hinged relative to the tank portion to facilitate 
opening and closing the cover. Referring to FIGS. 9 and 10, in an 
alternative embodiment the connector securely fastens a generally flat 
cover 120 to a tank 118. Both the cover 120 and the tank 118 are pipes of 
the type above discussed in that they have outwardly protruding flanges 
135 and 129 with mating faces 119 and 121 and tapered back sides 123 and 
125. The connector is essentially identical to the above-discussed 
invention and comprises a ring 124 and a plurality of rotatable clamping 
spools 127. An annular mounting plate 122 is oriented in a plane generally 
parallel to the flange 129 of the tank 118 and rigidly secured, e.g. 
welded, to the tank 118 at an axial position behind the flange 129. The 
ring 124 of the connector is preferably rigidly secured, such as by welds, 
to the mounting plate 122, but may merely rest on the mounting plate 122, 
e.g. when the tank axis is oriented vertically. The annular mounting plate 
122 is axially positioned on the tank 118 so that the ring 124 and thus 
the connector lies generally in the plane of the flange mating faces 119 
and 121. 
The ring 124 and the cover 120 are hingedly connected to one another so 
that the cover 120 may be easily opened and closed over the open end of 
the tank 118. The ring 124 which is preferably rigidly secured to the 
annular mounting plate 122 has radial extensions 131 and 132 with openings 
for the receipt of a hinge pin 130. The cover 120 has brackets 126 and 128 
welded to the upper surface which extend beyond the flange 135 of the 
cover and which also have openings for the receipt of a hinge pin 130. 
Thus the alignment of the openings in the brackets 126 and 128 of the 
cover 120 with the openings in the radial extensions 131 and 132 of the 
ring 124 and placement of the hinge pin 130 through these aligned openings 
permits hinged movement of the cover 120 with respect to the ring 124 and 
thus the open end of the tank 118. When the cover 120 is moved about the 
hinge pin 130 so as to close the cover 120 over the tank 118, the 
peripheries of the flanges 135 and 129 are in axial alignment, thereby 
eliminating the necessity of initially axially aligning the flanges. Of 
course, if the ring 124 and the hingedly connected cover 120 merely rest 
on the annular mounting plate, e.g. when the tank axis is vertical, the 
flanges 135 and 129 would be initially axially aligned by means of three 
of the clamping spools 127 in the manner previously discussed. 
In use, this embodiment of the invention operates essentially in the manner 
as previously described. That is, if the cover 120 is open and it is 
desired to securely fasten the cover 120 to the tank 118, the bolts 137 
are backed off, thereby permitting the spring clips (not shown) to force 
the spools 127 against the bottoms of the cutouts (not shown). The spools 
127 are then rotated so that the rims 139 are oriented radially outward. 
The cover 120 is then moved about the hinge pin 130 axis to close the 
cover. Because all portions of the spools 127 reside radially outward of 
the periphery of the flange 135 on the cover 120, the cover passes over 
the connector without obstruction. The mating faces 119 and 121 of the 
flanges 135 and 129 are now abutted. The spools 127 are rotated to orient 
the rims 139 radially inward and the bolts 137 are tightened to force the 
rim clamping faces radially inward to thereby generate axial clamping 
forces to the flanges. When it is desired to open the cover the bolts 137 
are backed off and the spools 127 are rotated so that the rim clamping 
faces are again oriented radially outward, thereby permitting the flange 
135 and the cover 120 to pass over the spools 137 and the connector 
without obstruction when the cover 120 is rotated about the hinge pin 130 
axis. This embodiment of the invention thus permits frequent making and 
breaking of pipe flange connections to be accomplished with ease. 
While the preferred embodiments of the present invention have been 
illustrated in detail, it should be apparent that modifications and 
adaptations of those embodiments will occur to those skilled in the art. 
However, it is to be expressly understood that such modifications and 
adaptations are within the sphere and scope of the present invention as 
set forth in the following claims.