Improvements in Metallic Rod Packing.
Year: 1891

page_text: Date of Application, 6th Jan., 1891-Accepted, 7th Mar., 1891
COMPLETE SPECIFICATION.
Improvements in Metallic Rod Packing.
I, EDWIN PEAR MONROE, of No. 133, South Fourth Street, Philadelphia, in the
County of Philadelphia and State of Pennsylvania, United States of America,
Mechanical Engineer, 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 improvements relate to what is known as segmental metallic rod packing (of
the general character shewn in the Patent No. 4890 in the year 1880). Such
packings are self-adjusting, that is to say, adapted to move within a packing case
laterally to accommodate the lateral movements of piston rods etc. in motion. In
such packings as heretofore made, much frictional resistance has been experienced,
owing to the fact that the pressure of steam has been brought to bear altogether
upon one side, so that the exact fitting parts, moving in contact to accommodate the
changing lines of reciprocation of rods have been subjected to undue wear, and have
not, under high pressure of steam been movable with sufficient freedom.
By my improved construction I admit steam upon both sides of plates and
packings, so that the frictional resistance of moving parts is largely reduced by the
balancing of steam pressure upon opposite sides I also provide for making some of
the parts in sections, which is advantageous for reasons set forth below.
In the drawings
Figure is a diametrical section of a packing case, and its packing showing
a part of a rod in elevation.
Figure 2 is a side elevation of the packing detached from its casing.
Figure 3 is a plan view to a smaller scale of one set of segmental packings, and
its supporting ring detached.
Figure 4 is a similar view, showing the other set of segmental packings in position
at right angles to that shown in Figure 3.
Figure 5 is a diametrical section of the packing case showing bolts which secure
it to its end plate.
Figure 6 is a side elevation of the annular spherical bearing piece.
Figure 7 is a bottom plan view of the same.
Figure 8 is a side elevation; and
Figure 9 is a plan view of one face of a cap plate for one end of the segmental
packing.
Figure 10 is a side elevation of the packing rings, and a part of a rod which is
shown in plan in Figures 3 and 4.
Figure 11 is a side elevation; and
Figure 12 a plan view of another cap plate for the packing which I call a
follower.
Figure 13 is a diametrical section of the end plate of the casing, showing springs,
which are located between it and the follower as shewn in Figure 1.
Figure 14 is a diametrical section of a packing case and its packing showing a
part of a rod in elevation, the cap plate and the follower being respectively composed
of two parts bolted together.
Figure 15 is a side elevation to a smaller scale showing the two parts of the cap
plate bolted together.
Figure 16 is a plan view of the same.
Figure 17 is a side elevation of the cap plate showing the cars or lugs employed
for bolting its parts together.
Figure 18 is a plan view of the follower made in two parts.
Figure 19 is a side elevation of the same, and

page_text: Figure 20 is another side elevation viewed at right angles to that shown in
Figure 19.
Referring to the letters upon the drawings, A indicates the case, and B its end
plate, which are secured together by the screw bolts C. The case and the end
plate are as usual provided with openings for a rod D, of a diameter considerably
larger than that of the rod in order to allow variation in the lines of reciprocation
of the rod without bringing it in contact with the casing or its end plate.
E indicates ordinary segmental metallic packings secured in rings F and held in
place by springs G.
There are two sets of these packings as usual the construction and operation of
which are well known and need not be described.
H indicates an annular bearing piece fitted steam tight at I to the case, so as to
be capable of tilting in any direction in the manner of a ball and socket joint.
K indicates a cap plate bearing against the bearing piece H, see Figure 1, on one
side and against one of its packing rings on its other side. This cap plate is
provided with an annular bushing & of Babbitt metal, which fits substantially steam
tight around the rod and reduces the friction incident to the reciprocation of
the rod.
The packing rings and their segmental metallic packings being well illustrated
in Figures 1, 3 and 4 and being of ordinary construction I will not describe them in
detail.
M indicates the follower, which bears upon one side against one of the packing
rings and upon the other side upon springs N and is provided with a Babbitt metal
bushing m.
The rod packing case is in practice secured to a steam chest, and steam is of
course admitted into the case through its end plate. By the ordinary construction
of segmental packing for rods, the steam pressure is brought wholly to bear upon
one side of each of the parts whose contact with an adjacent part is intended to
form a steam tight joint and at the same time to provide for movement of the joined
parts. The result is that as the cap plate and follower are moved by the rod
laterally, great friction and wear occur between the movable parts forming the
steam tight joints. To reduce this friction and wear to the minimum I provide
steam ports between these moving parts leading to steam chambers, whereby steam
is introduced between the movable parts on the opposite side from that where it has
ordinarily solely pressed. The result is that it balances part cf its friction inducing
pressure, and thus reduces the friction leaving still a sufficient preponderance of
pressure to form steam tight joints.
O in Figures 6 and 7 indicates steam ports leading to the annular steam
chamber P, in that surface of the bearing piece H against which the cap plate K
bears. Q, Figures 8 and 9 indicates ports formed in a surface of the cap plate K
leading to the annular steam chambers R in the plate. In this instance instead of
having one large steam chamber several small ones are provided, but that is merely
a formal change.
In Figures 11 and 12, S indicates ports in the follower leading to annular steain
chambers T. The ports and steam chambers in the cap plate and follower, it will
be seen reduce the friction between those parts and the segmental packings, and
packing rings by balancing steam pressure as above described.
By providing the ports and steam chambers described, in segmental metallic rod
packings about 50 per cent. more or less of the ordinary frictional resistance and
resultant wear and destruction of parts can be obviated.
In Figures 14 to 20 inclusive is illustrated that part of my invention relating to
forming some of the elements of the rod packing in two parts which are bolted
together. The elements thus constructed are the cup plate and the follower.
These are formed each of two equal parts provided with lugs or ears a having
tapered holes through them in which tapered pins & fit. These tapered holes and
pins are made with great nicety, so that when the nuts care screwed up the parts
will be drawn together exactly to place. The reason for forming these elements in

page_text: two parts is generally stated that of convenience and economy in renewing the
packings within a case after they become worn. In practice a case for a rod
packing will usually wear much longer than the moving parts within it because the
case can be made thick enough to endure for a long period without being too large
or cumbrous, but the moving parts within the case will ultimately become worn, so
as to need replacing, especially when used to pack rods, having very extensive
reciprocating and vibratory motion, as for example in the case of large marine
engines.
By making the element described in two equal parts they can be removed and
replaced by new ones without detaching the rod from its cross-head at one end or
its piston at the other, which is a great saving.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that
what I claim is :-
1. In a metallic rod packing, the combination with a main casing and the movable
parts adapted to accommodate the lateral movements of the rod, joined steam tight
and subject to steam pressure, and ports and chambers arranged between these
movable parts, as shown, so as to counterbalance the steam pressure, substantially
as set forth.
2. In a metallic rod packing the combination with the cap plate K and the
follower M each made in two parts bolted together and the rod D of the Babbitt
metal bushings L and m substantially as set forth.
3. In a metallic rod packing, the combination with the rod and packing rings, of
a cap plate made in two parts bolted together and a follower made in two parts and
bolted together with tapering pins substantially as set forth.
4. In a metallic rod packing, the combination of the casing and the packing
contained within the casing, and a plate through which the rod passes, composed of
separable parts united together by tapering pins, substantially as set forth.
Dated this 6th day of January 1891.
CARPMAEL & Co.,
Agents.