Year: 1887

page_text: Date of Application, 3rd May, 1887.
Specification Accepted, 3rd June, 1887.
I, EDMUND COGGSWELL CONVERSE, residing at 223, Ridge Avenue in the City of
Allegheny, and County of Allegheny and State of Pennsylvania, one of the United
States of America, Manufacturer, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
My invention relates to the joints employed in connecting the sections of pipe or
tubing and especially to that class of tubing employed as mains or conduits for natural
gas or similar gaseous material. This gas is exceedingly thin and subtle and great
difficulty has been experienced in providing a perfect joint for the sections of tubing
forming the mains or conduits through which it passes as it is liable to leak between
the threads of the ordinary threaded tubing, and it has been practically demonstrated
that the ordinary threaded sockets cannot always be made sufficiently tight for holding
this gas in large mains or pipes. After large experience in the laying of these gas
mains it has been found that the lock joint couplings for tubing such as are shown in
Specification accompanying application for Letters Patent of even date herewith, in
which the pipe is held from longitudinal strain, and means are provided for calking
the tubing and forming tight joints after the line is laid, give better results for large
pipe or tubing than any other construction of joint heretofore employed, and also have
the further advantage that as the pipe is not weakened by threading, a lighter and
cheaper pipe may be employed. Considerable difficulty has, however, been experienced
with these joints when employed on high pressure gas mains near the gas wells or
source of supply on account of the porosity of the cast iron of which these sleeves
or collars have been made, this not being the fault of the joint but of the materials of
which it is formed, as it is found that under very heavy pressure the gas will leak
through the pores of the cast metal and even though the cast metal sleeve does in
most cases form a tight joint at a moderately high pressure yet at a very heavy
pressure, such as from one hundred and fifty to two hundred pounds, the leakage of
gas when it occurs through the pores of the cast metal is perceptible when the
hand is placed close thereto, and therefore the ordinary cast metal coupling collar is
not quite perfect for mains carrying this gas under very heavy pressure. For this
reason it is desirable to obtain a perfect joint of this character in which there is no
the

page_text: liability of the gas leaking through the pores of the metal, and the object of my
invention is to so improve the class of couplings above referred to as to overcome
these objections to them, and to preclude the leaking of the gas through the pores of
the metal of which the coupling is formed.
To this end it consists generally in a coupling sleeve or collar having a cast iron
inner shell provided with locking seats or other suitable means for engaging with the
tube sections, and an outer wrought metal shell fitting around the inner shell and
extending beyond the ends thereof to form annular calking recesses at the ends of the
combined sleeve, the inner cast metal shell being entirely enclosed within the outer
.shell and the calking material when the coupling is in use and the dense texture of
the outer wrought metal shell precluding leakage through the same, while the calking
material precludes leakage at the ends of the coupling.
It also consists in such coupling sleeve having the inner shell first cast to shape and
the outer wrought metal shell shrunken around it, the outer shell binding upon the
inner shell and forming a strong union between them; as well as in certain other
details of construction hereinafter referred to.
To enable others skilled in the art to make and use my Invention I will describe its
construction and manner of use, referring to the accompanying drawing in which
Figure, 1, is a longitudinal central section of this coupling sleeve or collar showing
one tube connected therein and the other tube in position to enter and engage
therewith.
Figure, 2, is a sectional perspective view of the inner shell.
Figure, 3, is a like view of the outer shell, and
Figure, 4, is a cross section on the line, x-x, of figure, 1 of a detached portion of
the coupling and tube connected thereto.
Like letters of reference indicate like parts in each.
In forming my improved coupling, the inner shell, a, is first cast to shape, being
formed of cast metal in the ordinary manner and having therein suitable locking
recosses, b, or other devices for engaging with the sections of tubing to be connected,
the form of locking device preferred by me being the recesses, b, in the shell, with
which the lugs or rivets, c, on the tube section engage, though other forms of locking
or engaging devices by means of which the inner shell and the section of tubing can
be connected, may be employed. The inner face of the shell, a, has preferably formed
thereon the central ring, d, against which the ends of the tube sections butt or bear
so forming a smooth interior to the joint, and on each side of this ring the inner
face, I, within which the body of the tube sections fit, the locking seats or recesses, b,
being formed in these inner faces, and the ends of the shell being formed beveled to
direct the tube to place within the inner shell, these beveled faces also forming the
inner faces of the annular calking recesses at the ends of the collar.
This inner shell, a is made somewhat shorter than the finished coupling sleeve, and
over the inner shell fits the outer shell, f, which is made of wrought metal being forged
to shape in any suitable manner, and being of sufficient length to extend beyond the
inner shell, a, at each end of the finished collar as at, g, so as to form the calking
recess, h, at the end of the finished collars and beyond the inner shell, a. The ends of
the outer shell,, are preferably formed inwardly flaring or inclined as shown at, k, so
that when fitting over the inner shell they form the inwardly flaring annular calking
recesses by means of which the lead or other calking material employed will be held
to place after the joint is formed. Where the two shells are formed separately and
then connected the outer face of the inner cast metal shell, a and the interior of the
outer wrought metal shell, f, are formed accurately so that when the outer shell is
heated and expanded it can be placed over the inner shell and upon cooling will contract
and shrink upon the same, thus forming a solid combined cast metal and wrought
metal coupling sleeve or collar which can be employed in the same manner as the
coupling sleeve or collar shown in the application for patent made by me of even
date herewith.
As the locking seats are formed entirely within the inner faces, l, instead of between
said faces and the calking recesses the calking recesses may be made much smaller

page_text: and consequently require less lead or calking material and can be more rapidly and
easily calked.
In forming the joint the pipe sections are inserted within the coupling sleeve, and
engage with the recesses, b, or other suitable connections in the inner shell of the
coupling sleeve by means of the lugs, c, thereon or other suitable device and the lead
or other calking material is then poured into the calking recess, h, and calked in the
ordinary manner, thus forming the joint. The inner shell is thus entirely enclosed
by the outer shell formed of dense wrought metal and by the calking material at the
ends enclosed between the wrought metal shell and the body of the tube sections, and
the gas in passing through the coupling, though it may leak between the ends of the
tube sections and the inner central ring and between the interior of the cast metal
body and the exterior of the tube section, is prevented from escaping by means of the
lead or other suitable calking material within the calking recesses at the ends of the
collar, and even though the inner shell may be porous, so that the gas under very
heavy pressure might leak through the same, yet the outer wrought metal shell fitting
over the inner cast metal shell is of such density that it will prevent the escape of gas,
the texture of wrought metal being close and fine, so precluding the escape of gas,
and in case the gas should leak through the body of the inner shell it could only pass
along until it came against the calking material at the ends of the coupling collar by
which it would be prevented from escape. It is therefore evident that by my improved
coupling collar I am enabled to provide a practically perfect joint for gas mains
through which there is no liability whatever of gas escaping, as the texture of the
outer sleeve is so close and fine that it will prevent all escape of gas, and the only
objection to my patent for high gas or air pressures is thus overcome.
By the formation of the locking seats entirely within the inner faces I am also by
reducing the size of the calking recesses enabled to save a large amount of lead and
the labor and time of calking so large a mass of calking material.
The cost of my improved coupling is but little above that of the ordinary cast metal
collar, as the amount of cast metal employed is reduced, and after the ordinary forging
of the outer shell there is but little work required thereon.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed I declare that what I claim is :-
1. In joints for gas and similar mains, the combination of a cast metal inner.shell
provided with locking seats for engaging with the tube sections, and an outer wrought
metal shell fitting around and extending beyond the inner shell to form calking recesses,
substantially as and for the purposes set forth.
2. In joints for gas and similar mains, the combination of a cast metal inner shell
provided with means for engaging with the tube sections, and an outer wrought metal
shell fitting around and shrunken upon the inner shell, and extending beyond the same
to form calking recesses, substantially as and for the purposes set forth.
3. In joints for gas and similar mains, the combination of the inner cast metal shell
having the locking recesses, b, for engaging with the tube sections and the beveled
ends, e, and the outer wrought metal shell fitting around the inner shell and having the
inwardly flaring portions, k, extending beyond the same substantially as and for the
purposes set forth.
4. In tube joints, the combination with tubing having one or more lugs or other
connecting devices at or near the ends thereof, or a coupling collar having an inner
central face or faces, locking seats formed entirely within said face or faces and calking
recesses beyond said inner faces, substantially as and for the purposes set forth.