VALVES, VALVE SEATS ETC., MADE OF MICA
Year: 1887

page_text: I, ROBERT WASHINGTON TRAYLOR of No. 20 South 15th Street, Richmond, Virginia,
U.S.A., Brass founder, do hereby declare the nature of my invention for VALVES, VALVE
SEATS ETC., MADE OF MICA, to be particularly described and ascertained in and by the
following statement :-
This invention relates to valves organized to control the flow of steam, water, etc.
The object of my invention is to provide a valve, or valve seat, or both, which is im-
pervious to moisture, will resist acids, is not affected by heat, and possesses sufficient
elasticity to enable a steam tight fit to be made even though the valve or valve seat
be not exactly true. To this end the invention consists in constructing the working
or bearing surface of either the valve or the valve seat of a body of Mica. It is well
known that pure mica is found in the mines in slabs or sheets, and whatever their thick-
ness may be they are still, strictly speaking, sheets; each composed of an infinite
number of thinner sheets. A sheet of nica, however, as that termed is usually em-
ployed is of about the thickness of Bristol-board, or card-board; and to prevent mis-
understanding, I shall in the following description use the term sheets of mica
according to its general acceptation, referring to thicker sheets or pieces, as blocks of
mica. It will be understood that in carrying out my invention either sheets or blocks
of mica may be used with the same effect and result, for, so long as a sufficiently thick
body or mass of mica is obtained it is immaterial whether the laminae composing the
body are bound together or caused to adhere through natural agencies, or by mechanical
means. It will be understood that the practical difficulty in the use of mica for
valves, valve seats and like purposes, arises from the tendency of the laminae to dis-
integrate at the upper and lower flat surfaces, from slight abrasions, and to separate
from the other laminae by abrasions at the edges. In the structures hereinafter
described, where blocks or sheets of mica are employed, the tendency of the flat
surface to disintegrate is overcome by employing mainly the edges of the laminae
for wearing surfaces, and the tendency of the laminae towards separation under
abrasion of the edges, is prevented by the clamping hereinafter described.

page_text: Fig. 1 is a perspective view, in section, of a globe-valve, the valve and valve-seat
being constructed of sheets or laminae of mica.
Fig. 2 represents the mica-faced valve in elevation and plan view.
Fig. 3 represents the vica valve in section and plan view.
Fig. 4 is a perspective view, in section, of mica cock-case and turning plug.
Fig. 5 illustrates the plug in top plan, elevation and bottom plan.
Fig. 6 is a plan view of the case.
It will be understood that my invention is applicable to all classes of valves in which
the valve opening is closed by a solid valve disk or plug, and to cocks and faucets, and to
all classes of steam engine valves. In fact to any device the purpose of which is to check
or stop the flow of a liquor or vapor. In practicing my invention I clamp a block, or
number of sheets of mica tightly to prevent the fraying or splitting thereof, and work
said mica into the desired form by suitable means. The mica when suitably shaped,
or previous to such shaping, is fixed securely at the point where it is to be used,
whether on the end of a valve stem, as shown at V, Figs. 1 and 2, or within a valve
scat, as shown at S, Figs. and 3. A, Fig. 1, is the body or case of an ordinary
globe-valve, and B, the valve stem. The end b, of the stem is finished smooth, and
may be tapped centrally to receive a screw, but I prefer to use a downwardly extend-
ing threaded stud 61, made integral with the end b, of the stem.
I perforate the mica blocks or sheets, to permit of the passage of the screw or stud b',
and seat the body of mica upon the end b of the stem. A nut of less diameter than
the valve seat is then screwed upon the stud to compress the mica tightly between said
nut and the end of the stem, when the mica may be turned down to the proper shape
and size by the means usually employed for dressing or grinding valves.
In making a valve seat of the character shown in Figs. 1 and 3, I prefer, for con-
venience of construction, to line an exteriorly threaded thimble a with mica, and after-
wards secure said thimble within the case A. This thimble a, is provided at the bottom
with an inwardly projecting annular flange forming a shoulder upon which the mica
may be seated; and at the top with a female throad to engage the peripheral thread of
a metal ring or follower a¹. The mica may be cut into rings before insertion in the
thimble or placed therein, in sheets and bored out after being so secured. In either
case the ring a should be screwed down very tightly to compress the mica and the
latter dressed by suitable means to the desired shape and dimensions. It will be
understood of course, that the ring a¹ will be of a size to permit the valve to be seated
directly upon the mica.
The mica valve and valve seat may be used together, or the former may be used in
connection with a valve seat of metal or other substances, and the latter with any
preferred valve.
In the cock-case A¹ shown in Figs. 4 and 6, the entire plug chamber is formed
of mica. The construction may be as shown, the central portion of the case being
composed entirely of mica-sheets clamped tightly together by means of the end
plates A and tie bolts, or the outer portion of the case may be made of metal with
a central cavity of sufficient extent to adinit of compressing laminae of mica within it,
in a manner somewhat similar to that illustrated in Fig. 3, so that the cock-plug B, or
the working part of it, will rotate in a mica bearing. The cock-plug B is composed of
disks of mica clamped tightly between the top and the bottom plates 6 and 6 by
means of the two screw bolts passing on either side of the through way or opening.
It will be understood that I do not in this application wish to confine myself to mere
details of construction, as the principle involved in my invention admits of many
modifications in mechanical structure which would at once suggest themselves to
skilled mechanics.
A facing of mica for valves, valve seats, cock-plugs, plug-chambers, and similar
structures, possesses advantages over any other material known to me, as it is im-
pervious, not liable to fracture, will resist wear, is not corroded by contact of acids of
alkalies, is sufficiently yielding or elastic to permit of a very tight joint being made
without the necessity of the accurate grinding or fitting required in facings of metal,

page_text: stone, or glass, and can be subjected to extreme changes of temperature without
appreciable expansion or contraction.
I am aware that a flap-valve or gate of mica has been illustrated and described on
page 166, of a publication entitled, "The Plumber and Sanitary Houses," edited by
S. S. Hellyer, and published in 1880; but the described valve is composed of a thin
sheet of mica adapted only to resist a light pressure, and were the sheets thick enough
to resist a heavy pressure the mica would split or fray, as no means has been shown
or described by Hellyer to resist this natural tendency. My invention on the other
band, relates to those valves which have a solid, rigid disc or plug adapted to fit upon
or within a rigid seat, and I wish it understood that I do not claim that the device
illustrated and described in the before mentioned publication. I am also aware that
has been proposed to make a valve disc for hydrants of a number of discs of leather,
but this I do not claim.
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. A facing or bearing surface for valves, valve-seats and similar structures, the
same consisting of a body of mica clamped tightly to form a solid mass substantially
as before set forth.
2. A valve, the bearing surface of which is composed of a body of mica clamped
tightly to form a solid unbending mass, substantially as described.
3. A valve seat, the bearing surface of which is composed of mica substantially as
described.
Thi
LT1007