Improvements in Steam Traps.
Year: 1898

page_text: Date of Application, 16th Feb., 1898
Complete Specification Left. 16th Nov. 1898-Accepted. 23rd Dec., 1898
Improvements in Steam Traps.
We, JOHN ISAAC THORNYCROFT, of Eyot Villa, The Mall, Chiswick, in the
County of Middlesex, F.R.S., and JoHN EDWARD THORNYCROFT, of the same
address, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to steam traps of the kind constructed with parts
of material which at a given temperature have a greater co-efficient of expan-
sion than other parts and in which the opening and closing of valves is due to
such differences. Our object is in apparatus of this class to provide for the
ready opening in the manner indicated of valves of larger area than has hereto-
fore been usual so that a large quantity of water, such as the priming water
collected in the separator or separators of main steam pipes, can be quickly
discharged. For this purpose we construct apparatus with a comparatively
large valve which we will call the main valve and with a supplementary or
smaller valve which we will call the controlling valve and which alone is or
may be opened and closed by the action of parts of the apparatus due to differ-
ences in expansion and contraction, the main valve being operated by fluid
pressure.
As will be obvious our invention can be applied in connection with various
forms of steam traps of the kind above referred to.
According to one construction the valve case is formed with two passages
and constitutes a junction piece between the adjacent ends of two tubes the
other ends of which are secured to a bracket or carrier and are provided with
connections by which they can be secured the one to a separator and the other
to an exhaust pipe. The tubes are arranged one above the other and at an
angle to one another being nearest together at the valve case, and are made
of metals having different co-efficients of expansion, the one having the greater
co-efficient and made say of solid drawn brass tubing, being arranged at the
bottom, and the other having the smaller co-efficient, made say of steel tubing,
being arranged at the top. The controlling valve consists of a spindle that
extends downward into the valve case through a stuffing box and is carried
by a lever that is pivoted to the bracket or carrier and is prevented from moving
in a direction to lower the valve by adjustable nuts on a stud that extends
through one arm of the lever. Between this arm and the bracket or carrier is
or may be a spring that will permit the lever to move in the opposite direction
and allow the controlling valve to rise and so prevent any undue straining of
the parts and damage of the valve seat by excessive expansion of the tubes.
The lever and spring also enable the controlling valve to be raised for the
purpose of blowing through the trap when desired. The main valve is made
in the form of a hollow plunger through the bottom of which is a central hole
controlled by the controlling valve. It is made a loose fit in the valve case so

page_text: that water and steam can flow past it and is coned at its lower side to fit against
a correspondingly formed seat on the projecting end of one of the passages in
the valve case.
Improvements in Steam Traps.
We, JOIN ISAAC THORNYCROFT, of Evot Villa, The Mall, Chiswick, in the
County of Middlesex, F.R.S., and Joux EDWARD THORNYCROFT, of the same
address, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention has reference to steam traps of the kind constructed with
parts of material which have a greater co-efficient of expansion than other
parts and in which the opening and closing of valves are due to such differ-
ences. Our object is in apparatus of this class to provide for the ready opening
in the manner indicated of valves of larger area than has heretofore been usual
so that a large quantity of water, such as the priming water collected in the
separator or separators of main steam pipes, can be quickly discharged. For
this purpose we construct apparatus with a comparatively large valve which we
will call the main valve and with a supplementary or smaller valve which we
will call the controlling valve and which alone is or may be opened and closed
by the action of parts of the apparatus due to differences in expansion and
contraction, the main valve being operated by fluid pressure.
As will be obvious our invention can be applied in connection with various
forms of steam traps of the kind above referred to.
Fig. 1 of the accompanying illustrative drawings shows partly in side eleva-
tion and partly in longitudinal vertical section, one construction of expansion
steam trap in which this invention has been applied. Figs. 2 and 3 are detail
views showing modified constructions.
1 is a valve case formed with two passages 1ª and 1b and an annular con-
necting passage 1° surrounding the upper end of the passage 1b. This valve
case is arranged to constitute a junction piece between the adjacent ends of two
pipes 3 and 4 which are screwed into it and the other ends of which are secured
to a bracket or carrier 5 and are provided with connections 6 and 7 respectively
by which they can be secured the one (3) to the steam pipe, separator or other
vessel which it is desired to drain and the other (4) to an exhaust pipe. The
pipes shown are arranged one above the other and at an angle to one another,
being nearest together at the valve case 1. They are made of metals having
different co-efficients of expansion, the one (3) having the greater co-efficient
and made say of solid drawn brass tubing, being arranged at the bottom, and
the other (4) having the smaller co-efficient, made say of steel tubing, being
arranged at the top. 8 is the controlling valve consisting of a spindle that
extends downward into the valve case 1 through a stuffing box 9.
10 is a.
lever that is pivoted to an extension 5 of the bracket or carrier 5. The valve 8

page_text: may, as shown in Fig. 1, be carried by the lever 10 which is then formed with
a forked end, but it is preferable to arrange the valve 8 as shown in Fig. 2,
wherein its outer end is kept in contact with the lever 10 by a coiled spring 8*
that encircles it and is located between a head S" on the valve and the gland
of the stuffing box 9 or as shown in Fig. 3, in which case, it is forced outward
by fluid pressure upon its inner end. The lever 10 is prevented from moving
in the direction of the arrow a, to depress the valve, by adjustable nuts 11
on a stud 12 which extends through one arm of the lever 10 and is pivoted
to the bracket 5.
In some cases one of the nuts is enlarged so as to form a hand wheel. It
is found convenient to graduate its edge and to so mark the graduations that an
index shows the best position for the nut (or wheel) to suit any desired working
pressure. Between this arm and the bracket 5 is or may be a spring 13 that
will permit the lever to move in the opposite direction, viz:-in the direction
of the arrow b, and allow the controlling valve 8 to rise and so prevent any
undue straining of the parts and damage of the valve seat by excessive ex-
pansion of the tubes. By depressing the long arm of the lever 10 in the
direction of the arrow 6 against the action of the spring 13, the controlling
valve 8 can be raised or allowed to rise for the purpose of blowing through
the trap when desired. 14 is the main valve made in the form of a hollow
plunger through the bottom of which is a central hole 14" controlled by the
controlling valve 8. This main valve is made a loose fit in the valve case 1 so
that water and steam can flow slowly between it and the valve case and enter
its interior, and is shaped at its lower side to fit against a correspondingly
formed seat 1 on the adjacent projecting end of the passage 1b.
The working of the steam trap is as follows:-
The tubes 3 and 4 before steam is supplied to the pipes to which the trap
is connected, occupy the position shown approximately in the drawing, the
valve case being in its lowermost position with the main valve 14 resting on
its seat 1 and away from the controlling valve 8 so that it is free to lift. Upon
steam being supplied to the pipes connected to the separator and trap any
water they may contain .or which is formel by condensation, upon flowing
into the lower pipe 3 of the trap, will, by acting against the lower side of the
main valve, lift this valve and thus open a large outlet passage through the
pipe 4 by which the water can be quickly discharged.
Upon steam entering the pipe 3 behind the water, it will cause this pipe to
expand in length whilst the pipe 4 will not expand to the same extent, the
result being that the connected movable ends of the pipes 3 and 4 with the
valve case I will be raised sufficiently to cause the main valve 14 to be seated
against the controlling valve 8, and also against the seat 1d thereby preventing
the escape of steam from the trap. Steam or water of condensation, by flowing
past the exterior of the main valve 14 and acting upon the upper side thereof
will keep this valve against its seat 1d until by the contraction of the pipe 3,
due to water accumulating therein, the valve case is moved downward and the
main valve 14 consequently moved away from the controlling valve 8 which
will consequently open the hole 14 through the larger or main valve 14 and
permit the water that will have collected above this valve to escape through
the said hole and by relieving its upper side of pressure will permit this valve
to be raised by the water pressure on that annular part of its lower surface that
is around the seat 1d. The main valve being thus opened, water will again
be quickly discharged from the pipe 3 through the large passage 1b and pipe 4
until by steam again entering the pipe 3 this pipe expands and again raises
the valve case 1 sufficiently to seat the main valve 14 against the controlling
valve 8 and close the opening 14 whereupon the main valve will become seated
upon the seat 1d and so close the opening 1b, the fluid pressure upon its upper
side then keeping the said valve upon its seat. The above described operation
will be repeated intermittently whilst the trap is in use.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that
what we claim is:
1. A steam trap having a comparatively large main valve which is adapted
to be operated by fluid pressure and is controlled by a supplementary valve
that is itself opened and closed by the differences in the expansion and contrac-
tion of parts of the trap that are acted upon by steam or water, substantially
as described.
2. In a steam trap, the combination with two water discharge pipes fixed
at one end and movable at the other, of a valve case connecting the movable
ends of said pipes together and formed with passages whereby the one pipe can
be placed in communication with the other, a main valve mounted to work in
said valve case and formed with a relief opening therethrough, said valve being
adapted to close one of the passages through said valve case and to be then
subjected over part of one of its sides to the pressure of water in the other
passage, another passage through which water can pass to the opposite side of
said main valve, and a normally stationary controlling valve adapted to open
and close the relief opening through said main valve when said valve is moved
from and towards said controlling valve by one of said pipes contracting and
expanding to a greater extent than the other, substantially as described.
3. Steam traps constructed, arranged and operating as described with refer-
ence to and shown in Fig. 1; or modified according to Fig. 2 or to Fig. 3 of
the drawings annexed
vember 1898.
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.
Dated this 16th day of November 1898.
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.