Improvements in Double Bеat valves.
Year: 1899

page_text: Improvements in Double Bеat valves.
We, The Honourable CHARLES ALGERNON PARSONS, Engineer, and ARCHIBALD
DOUGLAS WASS, Engineer, both of Heaton Works, Newcastle-on-Tyne, do hereby
declare the nature of this invention to be as follows:
Our invention relates to double beat valves and its object is to produce a double
beat valve in which the difficulty of keeping both seats tight is effectively over-
come.
In double beat valves of the ordinary construction there is considerable diffi-
culty in securing and maintaining pressure tightness, owing to several causes
including:
--
1. Elasticity of the valve casing under pressure exceeding the elasticity of the
valves.
2. The difference of the coefficient of expansion of the valve case and valve from
irregularities in the composition of the metals.
3. Differences of temperature in parts of valve and casing (when used for steam
or gas) due to the difference of pressure.
4. Stresses thrown on the valve body by the pipes to which it is attached.
Our invention provides a means for remedying this defect and consists in intro-
ducing into one or both of the valves, or one or both of the valve seats constituting
the double beat or equilibrium valve a certain amount of elasticity which shall
greatly exceed any of the causes of leakage.
To carry out our invention in the case of a double beat valve of ordinary type,
we prefer to provide elasticity on the larger of the two valves, and to place the
valve body so that the pressure side is on the back of the larger valve. But this
arrangement may be reversed and the smaller valve may be elastic and the pressure
act on its back.
We also prefer to construct this valve of a moderately thin disc of hard elastic
phosphor bronze sheet or other suitable material, this disc is securely held on the
valve stem by nuts and washers or other suitable means, and so shaped as to
allow the edge of the disc a small amount of freedom or elasticity or both in the
direction of the valve stem, the object being that when the valves are ground on
to their seats to allow both to be seated at the same time, then the pressure of the
fluid on the back of the elastic valve keeps it perfectly tight, while the pressure
of the valve screw assisted by the pressure of the fluid on the central portions
of the larger valve keeps it tight as in the case of an ordinary single screw down
valve, but the power required to shut it is practically the same as in the case of
an ordinary double beat valve. In opening, the force required is practically the
same as with an ordinary double beat valve."
We prefer to grind the valves so that one or other and preferably the elastic
valve seats itself first.
The washers and stem are so shaped as to prevent the elastic washer from

page_text: becoming unduly deformed by fluid or mechanical pressure. Sometimes we make
both valves elastic.
We provide stops or so shape the washers and valve stem holding the elastic discs
as to prevent the deformation of the discs by undue pressure in screwing down.
Sometimes we make the valve seats themselves elastic preferably by forming
them of annular discs of elastic material secured to the valve body.
Though we have only referred to single elastic discs in some cases we form the
elastic part of a compound of thinner elastic discs.
In some cases this compound disc is turned on its edge so as to fit into a
conical seat and thus secure a multiple steam tight joint by the several component
laminae. Sometimes we spin out or cup the edges of the discs, so as to secure
a multiple tight joint on a flat seat. Sometimes we corrugate the central portions
of the discs to increase their elasticity.
In some cases we prefer instead of forming the valve or seat of an elastic dise
or discs to provide the desired amount of freedom by allowing one of the valves
a slight freedom to slide on the valve stem the valve being provided with a
gland or packing, elastic or not, in which the stem can slide. This freedom may
or may not be controlled by a spring or springs.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester,
Agents.
We, The Honourable CHARLES ALGERNON PARSONS, Engineer, and ARCHIBALD
DOUGLAS WASS, Engineer, both of Heaton Works, Newcastle-on-Tyne, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
Our invention relates to double beat valves and its object is to produce a double
beat valve in which the difficulty of keeping both seats tight is effectively over-
come.
In double beat valves of the ordinary construction there is considerable diffi-
culty in securing and maintaining pressure tightness, owing to several causes
including:-
1. Elasticity of the valve casing under pressure exceeding the elasticity of the
valves.
2. The difference of the coefficient of expansion of the valve case and valve from
irregularities in the composition of the metals.
3. Differences of temperature in parts of valve and casing (when used for steam
or gas) due to the difference of pressure.
4. Stresses thrown on the valve body by the pipes to which it is attached.
Our invention provides a means for remedying this defect and consists in intro-
cing into one or both of the valves or one or both of the valve seats constituting
double or equilibrium valve a certain amount of play or elasticity which shall
atly exceed any of the causes of leakage. Where one valve is larger than the
er as is usually the case, we prefer to provide the elasticity on the larger
Ive and to place the valve body so that the pressure side is on the outside of

page_text: the larger valve. But this arrangement may be reversed and the smaller valve
he elastic with the pressure acting on its back.
The accompanying drawing illustrates one modification of our invention as
applied to a double beat valve of ordinary type.
The lower and smaller valve a is of ordinary construction; but the upper and
larger valve is formed of a moderately thin disc b of hard elastic phosphor bronze
sheet or other suitable material situated between a washer e and a plate c which
carries the guiding webs d. The disc b is so shaped and held as to allow its edge
a small amount of motion in the direction of and relatively to the valve stem f
due to the elasticity of the disc.
We arrange the valves on the stem and grind them so that the elastic valve
seats itself first but yields till the lower valve is also seated. The fluid pressure
on top of the elastic valve keeps it perfectly tight while the lower valve is held
down chiefly by the pressure of the spindle as in the case of an ordinary single
screw down valve. The forces required to shut and open this double beat valve
are practically the same as in an ordinary double beat valve.
The elastic disc is so constructed and held as to prevent it becoming unduly
deformed by fluid or mechanical pressure. Sometimes we make both valves with
elastic discs. In this case we may provide stops to prevent damaging the discs
by undue deformation in screwing down.
Sometimes we make the valves rigid and form the valve seats with elastic plates
such as b of annular form.
Though we have only referred to single clastic discs, in some cases we form
the elastic part of a compound structure composed of thinner elastic discs. In
some cases this compound disc is turned on its edge so as to fit into a conical seat
and thus secure a multiple steam tight joint by the several component laminae.
Sometimes we spin out or cup the edges of the discs so as to secure a multiple
tight joint on a flat seat. Sometimes we corrugate the central portions of the
discs to increase their elasticity.
.
In some cases we prefer instead of forming the valve or seat of an elastic disc
we provide the desired amount of freedom by allowing one of the valves
a slight amount of play by sliding on the valve stem, the valve being provided
with a gland or packing in which the stem can slide. This freedom may or
may not be controlled by a spring or springs.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. A. double beat valve in which one or both of the valves or one or both of the
valve seats have a certain amount of play or elasticity for the purpose of enabling
both valves to be accurately seated, substantially as hereinbefore described.
2. A double beat valve in which one of the valves such as a is rigid with the
valve stem and the other is formed of an elastic disc such as 6 for the purpose
of enabling both valves to be accurately seated, substantially as described and
as illustrated in the accompanying drawing.
T
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1000
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MARKS & CLERK,
18. Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester,
Agents.
MARKS & CLERK,
18. Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester,
Agents.