Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates to a steam trap
fitted to steam utilizing machines and instruments or
steam pipe arrangements for discharging steam condensate
generated therein out of said machines and instruments or
said pipe arrangements.
The present invention relates in particular
to improvements upon a free float type steam trap for
directly opening and closing a valve port arranged at the
lower part of said sump by means of a spherical float which
is disposed under a free state within said steam condensate
sump communicated with said steam utilizing machine and
instrument and which is actuated the raising and descending
motion due to buoyancy given by the condensate accumulated
within said sump.
One object of the present invention is to provide
a free float type steam trap which is improved on easy
operation with least decrease of the outflowing quantity
of liquid as compared with that in conventional trap,
in which the pressure gradient at a valve port is gently
tapered and a float is actuated stably accompanying no
violent seating on said valve port as well as followed by
no deformation and rupture of said float, thus no ripple
is occurred on the surface of the condensate and no leakage
of steam is taken place, and thus erosion problem at a
valve seat is minimized.
A construction in accordance with the present
invention includes a free float type steamed trap in which a
spherical float is accommodated under a free state within
a steam condensate sump provided with an inlet for introducing
O the condensate into the sump. A valve port is arranged
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to be disposed at the lower part of the steam condensate
sump and is adapted to be opened and closed by the spherical
surface of the float in which is subjected to ascending and
descending actions given with buoyancy imparted from the
condensate accumulated in the steam condensate sump. The
steam trap comprises an orifice positioned between and
communicating with the valve port and an outlet for the
condensate. There is a passage providing communication
between the orifice and the valve port and the passage has
an aperture area larger than the opening of the valve port
while the orifice has an aperture of 50 to 100% of the
opening of the valve port.
Further object of the present invention will be
understood on the basis of the description and the scope of
patent claim mentioned hereinafter with reference to the
accompanying drawings by way of example in a form of em-
bodiments of the invention.
Having thus generally described the nature of
the invention, reference will now be made to the accompanying
drawings, showing by way of illustration, a preferred em-
bodiment thereof, and in which:
Figure 1 is a sectional view of a free float
type steam trap according to the present
invention showing an example in a form
of an embodiment of the invention,
Figure 2 is a sectional view of a conventional
free float type steam trap showing a
lower half part thereof,
Figure 3 is a sectional view of a valve port
member illustrated in Figure 1 showing
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the same in an enlarged scale,
Figure 4 is an enlarged sectional view of avalve seat membex according to the
present invention similar to that illus-
~rated in Figure 3, showing the same in
a form of another embodiment of the
invention,
Figure 5 is a perspective view of a float cover
shown in Figure 1,
Figure 6 is a perspective view of an exhaust valve ;
shown in Figure 1, and
Figure 7 is an enlarged sectional view of a float
seat member shown in Figure 1.
Conventional free float type steam traps have been
constructed at the lower half part thereof to such a struc-
ture as shown in Fig. 2, while at the upper half portion
thereof, excluding a float cover, to a structure similar
to that shown in Fig. 1.
In Fig. 2, the valve port 10 is opened in the
steam condensate sump 12 at the lower part thereof. The
valve port 10 has a circular opening and i5 subjected to
be directly opened and closed by the spherical surface
of a spherical float 14 which is accommodated within said
sump 12 under a free state and is actuated to be raised
and descended corresponding to the liquid level A in said
sump. Said steam condensate sump 12 is communicated with
an outlet passage-way 18 through the valve port 10 and an
orifice formed at the downstream of said valve port 10.
With conventional prior art, in case of the
passage-way provided on the downstream side of said valve
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port 10 having hitherto been formed as large as possible
and employed a valve seat member 20 as shown in Fig. 2
for the purpose of obtaining a large capacity of outflowing
liquid, the aperture area of said orifice 16 has been so
large as four times or more than that of the valve port 10.
According to the foregoing conventional traps,
when the valve port 10 being opened, the pressure gradient
at the valve port 10 was turned out to be extremely large
and the pressure at the side of the valve port 10 in the
steam condensate sump 12 was figured out to be remarkably
reduced, thus the condensate accumulated within said steam
condensate sump 12 was subjected to be re-evaporated
actively at the side of the valve port 10 to cause volume
increase and to pass through said valve port 10 at high
velocity to be discharged to the outside of said trap.
Due to the reaction mentioned above, the float
14 was adapted to be given, at the vicinity of said
valve port 10, with heavy suction force in the direction
toward said valve port 10 along the outflowing stream.
So that, said float 14 had to be raised against the suction
force exerting to draw said float back in the direction
toward said valve port 10, thus having resulted in playing
a part of an obstacle as well as a resistant to be located
near said valve port 10 in the way of the outflowing stream,
while at the time of descent, said float 1~ was violently
seated on a valve seat 22 which has formed in said valve
port 10 due to said follow-up suction force, and had bumps
on the spherical surface of said float causing bruise in
the configuration thereof.
In case, consecutive flowing of condensate by
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a small quantity into said steam condensate sump 12, not
only undesirable operation set forth hereinbefore had
frequently been repeated, but also the condensate accumulated
within the stearn condensate sump 12 has been rippled on the
surface thereof due to furious fluctuation of the float 14
taken place frequently, the surface of said condensate has
been dimpled locally, and the dimple formed thereon was
continued to reach the valve port 10, whereby steam retaining
on the condensate at the upper part of its surface was
discharged out of said sump together with the outflowing
liquid.
Moreover, since the fluid flowing through the
valve port 10 was the condensate having relatively small
specific gravity and including re-evaporated steam, the
outflowing quantity was not so great as having been expected,
and the such outflowing fluid caused erosion problem at the
valve seat 22.
As shown in Fig. 1, a trap housing is primarily
composed of a main body 30 and a cover 32. The main body
30 is formed nearly in a cup-shape, and the cover 32 is fitted
through an annular gasket 34 to said main body 30 by means
of bolts 36.
The trap housing accommodates therein a substantially
cylindrical space having a semi-spherical lower part thereof,
an inlet 38 opened at the upper part of said cylindrical
space, and an outlet passage-way 40 provided at the terminal
end thereof with an outlet 42. Said inlet 38 is subjected to
be communicated with a steam utilizing machine or instrument,
etc. by a pipe arrangement.
Said main body 30 is provided therein with an
inwardly facing flange 44 for fitting thereto the float
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cover 46, under which is formed a steam condensate sump 48.
A hollow and actually spherical float 50 made of
rnetal spherical shell is disposed within said steam
condensate sump 48 under a free state. Said float 50 is
given with buoyance by the condensate accumulated within
said sump 48 to be raised and descended corresponding
to the condensate level B.
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The float cover 46, as shown in Fig. 5, is fitted to
said main body 30 at the inner peripheral wall thereof in such
a manner that an annular shoulder 54 and a protuberance 56
respectively formed on the peripheral wall at the lower end of
said cover 46 are adapted to be engaged with said inwardly
facing flange 44 and a notched groove formed on said flange at
the side of the inlet 38 correlatively to each other. so as
plurality of through-holes 52 perforated on the outer peripheral
edge of the ceiling wall of said cover are subjected to be
located at the half portion of the periphery facing the side
of said inlet 38. With such arra-ngement as set forth above,
an inflowing condensate from said inlet 38 is adapted to stream
downward along the inner wall of said main body 30 into the
steam condensate sump 48 after passing said through-holes 52
perforated.on the half portion of the outer peripheral edge
at the side of said inlet. So that, in case of prouiding a
valve port at the opposite side of the inlet 38 as will be
elucidated hereinafter, fluctuation of the condensate level
at.the spot adjacent to said inlet as well as of the f]oat 50
caused by the flowing-down.condensate can be reduced to the
minimum.
On the ceiling wall of the float cover 46 is formed a
buffer surface 58 having a radius of curvature substantially
equal to that of said float 50 so as to alleviate the impact
load imparted by quick ascent of said float 50 which comes into
collision with said cover 46. Further, the center on the
ceiling wall of said float cover is protruded upright and is
provided with a throughhole 60 for effecting with facility the
ventilation of gas staying in the upper and the lower spaces of.
the float cover 46.
A cylindrical filter 62 is arranged to be interposed
between said inlet 38 and said cylindrical space. .. -
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An exhaust valve chamber 66 is formed on the upper
part of said cylindrical space partitioned by said filter 64
ancl is provided therewithin an exhaust valve 70 shown in Fig. 6
which effects to open and close an exhaust valve port 68 formed
on the ceiling of said chamber 66. Said exhaust valve 70
comprised, as shown in Figs. 1 and 6 respectively, a bimetal
72 which is adapted to be deformed to a convex shape in the
upward direction at a high ambient temperature, while at a low
ambient temperature is curved to be a convex shape in the down-
ward direction and an-exhaust valve body 74 fitted to said
bimetal 72 to be protruded upward at the center thereof.
A valve port 68 is communicated with the outlet passage-way
40 through an exhaust passage-way 76. With such a structure
as mentioned above, when the trap is subjected to be cooled
due to radiation caused by hindrance against inflow of the
condensate under such conditions as of low temperature at the
initial starting stage in operation as well as that the trap is
filled with air in the interior thereof, said exhaust valve
body 74 effects to open the valve port 68 for discharging low
temperature condensate and air, while the trap being at a high
temperature, said exhaust valve body 74 effects to close the
valve port 68 as shown in the drawings.
The lower-limit location of the float 50 is defined
by a float seat member 80, as shown in Fig. 7, provided in a
float seat 7-8. Said bottom seat member 80 is composed of a
substantially cylindrical member airtightly engaged within
the bottom wall of said main body 30 through an 0-ring 82 and
a screw member 84 screwed in said main body 30. Said screw
member 84 is screwed in and out by a tool which is adapted to
be engaged at the tip thereof within a notched groove, that is
a slot of the screw formed on the lower end surface thereof
for minutely adjusting the location of the upper end plane 88.
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There~ore, the lower limit location of the float 50 can be
defined accurately so as to block the foregoing valve port 10
completely. The reference numeral 90 designates a protective
shield.
A valve seat member 92 is fixed to the lower side wall
opposite to the side of the inlet 38 of said steam condensate
sump 48. With reference to Fig. 3 showing the valve seat
portion in an enlarged scale, said valve seat member 92 is formed
in a substantially cylindrical shape and is engaged airtightly
within an engagement port 94 of the main body 30 through an
0-ring 96, and a shoulder 98 formed on the outer periphery of
said valve seat member 92 comes into contact with the side
edge of the outlet passage-way 40 opened in said engagement
hole 94, and the outer end 100 of said valve seat member 92
comes into contact with the inner edge of a plug 104 screwed in
a hole 102 for fitting the valve seat member, thus the valve
seat member is fixed to a predetermined position.
The inner end of said valve seat member 92 is protruded
into said steam condensate sump 48 to be positioned therewithin
so as to be turned out an annular valve seat 108 which forms a
valve port 106. Said valve seat 108 is formed with plane
surfaces, while said valve port 106 is formed in a circular
opening, and both of which are adapted to be blocked completely
with a spherical surface of said float 50. The aperture area of
said valve port 106 is defined, as similar to that of conventional
trap, due to the following two factors, one of which is an
actually effective buoyancy figured out in such a manner as
multiplying the maximum effective buoyancy exerting on the float
at 50 to be utilized as a valve opening force by the safety
factor ranging from 0.8 to 0.9, and the other of which is a
differential pressure of fluid at said valve port 106 exerting
on the float 50 as a valve closing force.
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A passage-way 110 formed with the valve seat member
disposed on the downstream of said valve port 106 is possessed
with an aperture area larger than the opening area of said valve
port 106 and is communicated with the outlet passage-way 40
through an orifice 112 provided on the peripheral wall of said
valve seat member 92. Said orifice 112 is perforated to be
arranged co-axially with said outlet passage-way 40 for the sake
of avoiding an erosion exerted on the inner peripheral wall of
said outlet passage-way 40 by drainage flowing out through said
orifice llZ.
The aperture area of said orifice 112 is designed to
be larger by 0.5 to 1.0 times than that of the valve port 106.
In case of the aperture area of said orifice i12 being designed
to be srnaller than the opening area of the valve port 106, the
internal pressure of said passage 110 formed in the valve seat
member is adapted to be increased at the operation for opening
the valve poxt and the pressure gradient at the valve port 106
can be tapered gently. So that re-evaporation at the side of
said steam condensate sump 48 of the valve port 106 can be
restrained, and the flow passed through the valve port 106
contains mostly the condensate to become a slowly running stream
minimizing erosion problem at the valve seat 108, thereby the
suction force in the direction toward the valve port 106 with
respect to the float 50 is weakened, thus resulted in stable
operation of the float 50 in the upward and downward movement,
which operation accompanies no violent seating of the float 50
on the valve seat 108 as well as no deformation nor rupture of
the float, furthermore, no ripple brought forth on the surface
of the condensate nor any live steam discharge out of the
valve port 106 originated from formation of dimples on the
condensate-level at the upper surface above said valve port 106.
The smaller is made the aperture area of the orifice 112, the
more distinguished becomes the effect enumerated above, moreover,
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the greater is decreased the outflowing quantity. However, with
the aid of reduction in the aperture area of the orifice 112,
the contents of re-evaporation steam in the condensate passed
through the valve port can be reduced, therefore, the decrease
in l,he outflowing quantity can be effected in the less amount
with the aid of reducing the aperture area of the orifice 112
than a conventional process with the opening area of the valve
port 106. According to the result of various experiments, the
outflowing quantity, when the aperture area of the orifice 112
being defined to the dimensions by 83% of the valve port 106, is
found to be reduced by only 2% than that in the normal aperture
area. Even though the outflowing quantity depends upon the
conditions of the condensate such as, for instance, pressure,
temperature, the configuration of the valve seat portion, etc.,
such effects as stabilization in the operation of the floatland
the like can be achieved within the range of satisfactory decrease
in the outflowing quantity provided that the dimensions of the
orifice 112 is defined larger than the opening area of the valve
port 106 to the range between 0.5 and 1.0 times.
Fig. 4 shows another embodiment of the present invention.
A valve seat member 292 provided with a valve port 306 formed in
an annular valve seat 308 is screwed in a main body 230 to be
secured thereto through a metal gasket 296 at the side of a steam
condensate sump 248. The inner wall of a passage-way 310 formed
within the valve seat member disposed on the downstream of said
valve port 306 is of a hexagonal shape to be suitable for engaging
with a tool which is serviceable to a screw-in operation. At the
outer end of said passage-way 310 is disposed a member 400 for
- forming an orifice 312, both of said member 400 and the outer
end of said valve seat member 292 are connected by welding with
the main body 230 at the weld 402 as shown in the drawing.
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The aperture area of the orifice 312 is designed to
be such a dimension similar to that of the foregoing embodiment
by 0.5 to 1.0 times as large as the opening area of the valve
port 306, wherefore effects similar to those of the initially
mentioned embodiment can be obtained.
The above-mentioned structural arrangement in this
embodiment brings about efficient airtight sealing between
constitutional elements which is more reliably and securely
effected than in the initially mentioned embodiment, thereby
the constitution in this embodiment is effectively applicable
to high temperature traps.
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