AN IMPROVED ARRANGEMENT OF PISTON PACKING, PRINCIPALLY APPLICABLE TO HYDRAULIC APPARATUS
Year: 1859

page_text: LETTERS PATENT to Marc Antoine François Mennous, of the British
and Foreign Patent Offices, 39, Rue de l'Echiquier, Paris, in the
Empire of Erance, for the Invention of "AN IMPROVED ARRANGEMENT OF
PISTON PACKING, PRINCIPALLY APPLICABLE TO HYDRAULIC APPARATUS."—A
communication from Casimir and Celestin Dabbène, residing at Verduno,
Sardinian States.
COMPLETE SPECIFICATION filed by the said Marc Antoine François
Mennons at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 12th September 1859, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARK
ANTOINE FRANÇOIS MENNONS, of the British and Foreign Patent Offices
39, Rue de l'Echiquier, Paris, in the Empire of France, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED ARRANGE-
MENT OF PISTON PACKING, PRINCIPALLY APPLICABLE TO HYDRAULIC APPARATUS,'
(communicated to me by Messrs. Casimir and Celestin Dabbène, of Verduno,
in the Sardinian States,) and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent for the
same, and have made solemn declaration that it is a communication.
C

page_text: NOW KNOW YE, that I, the said Marc Antoine François Mennons, do
hereby declare that the following Complete Specification, under my hand and
seal, fully describes the nature of the Invention, and the manner in which the
same is to be performed, reference being had to the accompanying Drawing
and to the letters marked thereon, that is to say :-
The packings generally employed in the pistons of pumps and other
hydraulic or analogous apparatus are subject to the disadvantage of exercising
a continuous pressure in the calibre of the cylinders in which they work, thus
giving rise to a considerable amount of wear and tear and to a needless
expenditure of force. The object of the Invention communicated to me is to
obviate this disadvantage by an improved arrangement of packing, the
pressure of which is exerted on the outer circumference of the piston (instead
of on the inner circumference of the cylinder) and only during the stroke by
which the vacuum is produced, the return or waste stroke being free from
friction. In a word the action is only exercised when indispensable to the
working of the apparatus, and is suspended when no longer of use.
Figure 1 of the accompanying Drawing represents a plunger or piston of
the same diameter throughout; Figure 2 is a pump body or outer cylinder
enclosing this piston; Figure 3 is a collar forming the improved packing;
Figure 4 is a modification of the collar, Figure 3. The packing, Figure 3, is
formed of two bands (of leather, caoutchouc, or other suitable matter) the
length and breadth of which vary according to the diameter of the piston.
These bands are bevelled off at each extremity, the under edge of each is
turned over so as to form a rim, and the two being coiled and brought
together with the bevelled extremities overlapped, a complete collar or circle is
obtained. The collar thus formed is placed rim downwards on a metallic or
other suitable circle a, corresponding with the shoulder plates b, b, cast on the
centre of the pump body, between which plates it is firmly clamped down by
bolts or screws. The plunger, Figure 1, the outer circumference of which is
exactly equal to the inner circumference of the collar, being then placed in
position, the apparatus is complete. It is obvious from the above that the
collar or packing, while fitting closely to the piston, is entirely independent of
it, as also of the inner surface of the main cylinder to which it is only attached
at the point b, b. The apparatus thus mounted, its action will be readily
understood. When at rest the packing, as above, noted, surrounds the piston
with little or no adherence, while a certain space remains free between its
outer circumference and the inner sides of the main cylinder. On the upward
stroke the air contained in the upper part of the pump body, and in the blank
space, tends naturally to fill the vacuum formed beneath, and in so doing

page_text: presses the packing against the outer circumference of the piston or plunger.
When the latter has reached its highest range the equilibrium is re-established
by the entry of the liquid, the atmospheric pressure on the packing ceases and
the piston returns to its place with little or no effort, the friction on its surface
being entirely suspended. Instead of forming the collar of two bands over-
lapped at the extremities, a number of sections may be employed in following
the same arrangement, or a continuous collar may be formed of a single band
or circle as shewn in Figure 4. Among the advantages inherent to this
system of packing may be noted,-
1stly, absence of pressure on the downward or waste stroke of the piston,
consequent absence of wear and tear and increase of power with economy of
force in working.
2dly, uniformity of action and non-liability to injury or deterioration.
3dly, facility and economy of application to apparatus of the largest diameter,
the necessity of dressing and polishing the interior of the cylinders being
entirely obviated.
Having thus described the nature of the said Invention and the manner of
carrying it into effect, I would remark that although an ordinary vertical
hydraulic pump body has been chosen to illustrate the application of the
improved packing, the same principle may be as readily adapted to all the
known systems of pumps and other analogous apparatus at present known, I
do not therefore confine myself to any of the minor details above laid down,
but claim largely the formation and arrangement, substantially as above des-
cribed and represented in the Drawing, of a packing for the pistons of pumps
and similar apparatus, which packing, mounted between the piston and its
cylinder, exerts its action during the effective or working stroke only, the
return or waste stroke being free from pressure.
In witness whereof, I, the said Marc Antoine François Mennons, have
hereunto set my hand and seal, this Tenth day of September, in the
year of our Lord One thousand eight hundred and fifty-nine.
M F MENNONS
MF
MENNONS (L.S.)