Note: Descriptions are shown in the official language in which they were submitted.
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escription
AUTOMATIC DRAIN VAI,VE
Technical Field
This invention relates generally to
float-activated drain systems for liquid
reservoirs, and more particularly to an automatic
drain valve for traps used in the accumulation of
condensable materials and other contaminants from
pneumatic systems and the like.
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Backqround Art
It is conventional to use filters and
separators for removing foreign objects, and
condensing and removing water and other
condensable liquids, from pressurized air lines
and the like. Typically, such filters include an
air inlet~ an air outlet and a filtering element
mounted between these elements in the flow path.
Such filters also include a reservoir or filter
bowl through which the air flow is at least
partia~lly passed causing the moisture and other
condensate in the air to be collected and
condensed on the inside surface of the reservoir
or bowl.~ The force of gravity causes such
con~ensed materials to accumulate at the bottom of
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the reservoir together with any other forei~n
objects. Periodically, this acc~mulated materlal
and liquid ~ust be discharged when the reservoir
or filter bowl has become full of material.
Numerous drain systems have been devised for
the discharge of the accumulated material. Two
such devices are shown in U. S. Patent No.
3,980,457, issued to J. I. Smith on September 14,
1974, and in U. S. Patent No. 3,993,090, issued to
Paul M. Hankison on November 23, 1976. In the
first of these two patents, there are a pair of
valves, a pilot valve and a discharge va]ve. The
pilot valve is magnetically operated and includes
a float which moves in response to changes in the
liquid level within the reservoir to magnetically
open and close a fluid valv~e in response to that
li~uid level. Opening of the fluid valve may
thereafter cause the opening of the second valve
for other operations such as the drainage of the
reservoir. In the second of the patents, there
are also two valves, a pilot valve and a discharge
valve. In this device, a float is held in a
submerged condition for a time to create a
superbuoyancy condition. When a sufficient
superbuoyancy condition is achieved, the float
suddenly rises to the surface of the liquid
causing a snap action of the pilot valve. This
opening of the pilot valve then quickly opens the
discharge valve for the removal of material
~ contained within the reservoir. In both of these
patents, the pressure of the pneumatic system to
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which the trap is attached is the driving force
which opens the discharge valve.
Since the operating valves and the drain
valves are located within the reservoir, various
disadvantages exist in the devices described in
the above-identified patents. For example, the
discharge valve or its operator may be damaged by,
or may collect, dirt and other abrasive materials
during the discharge operation. Also, they may be
affected by corrosive action since they are in
contact with the collected material. ~hese
deleterious conditions affect the future correct
operation of the discharge valve. Further, since
the discharge valve is located within the
reservoir as part thereof, it is a difficult and
an expensive procedure to_replace components of
this discharge valve. Since the pilot valve also
is operated by the air pressure of the pneumatic
system to which the reservoir is connected, this
valve may become contaminated with some of the
impurities.
Still other of these known devices for
accumulating condensate and impurities from
pneumatic systems are described in the background
sections of the above-identified patents.
Accordingly, it is an object of the pxesent
invention to provide a drain system for a
reservoir utilized in the accumulation of
condensate, and impurities from pneumatic systems,
wherein the discharge valve is located externally
to the reservoir to facilitate replacement of
components, if necessary.
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It is another object of the present invention
to provide a discharge valve for the reservoir
which incorporates a self-cleaning feature whereby
dirt and other such impurities have neyligible
effect on valve operation and provides for a
positive shut~off of every cycle without leaks
therefrom.
Another object of the present invention is to
provide a pilot or control valve housed in a
separate chamber integral with, but separate from,
the main reservoir area where collected material
is stored whereby the control valve is not
affected by pressure, dlrt and other contaminants
which would cause most pilot valves to fail.
It is still another object of the present
invention to utilize a palr of magnets of normally
opposite polarity, one in a valve plug and one in
a float, that are magnetically coupled such that
one of the magnets effectively reverses polarity
when the float within a liquid reservoir reaches
the uppermost position, thereby providing a snap
opening of this valve. These magnets are so
positioned that at the lowest level of the float,
the magnet is again effectively reversed in
polarity causing the rapid closing of the
associated valve.
Other objects and advantages of the invention
will become apparent upon reading the hereinafter
detailed description with reference to the
drawings.
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Disclosure of the_Inventlon
In accordance with the invention, an
automatic drain valve system is provided for the
dischar~e of accumulated condensed materials and
other ~oreign matter from a reservoir when the
xeservoir is filled to a predetermined level. The
valve for the actual draining is positioned
externally to the reservoir. Filtered pressurized
air, from a separate source, is fed to the
operator of the device valve and to a control
valve isolated from, but within the reservoir
itself. This pilot or control valve is normally
maintained in a closed position by a pair of
magnetically-coupled magnets, one being in the
control valve plug and one in the float
surrounding the control valve within the
reservoir. The polarity of thes0 magnets is
chosen such that when the float is in the lowest
position or is rising within the reservoir, the
magnets oppose each other. This causes the
control valve plug to close against the control
valve seat. When the float reaches its uppermost
position, the relative polarity of one of the
magnets is effectively reversed causin~ the
control vaIve plug to move away from the control
valve seat thereby permitting pressurized air flow
to the drain valve operatox with the result that
the drain valve is suddenly opened. This
e~fective reversed polarity of one magnet persists
until the float reaches its lowest position at
whl~h tire the~polarity effectively reverses.
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This reversal causes the control valve plllg to
again move against the control valve seat and the
air pressure to the drain valve operator is
reversed and/or vented causing the drain valve to
suddenly close. The pressure at the control valve
determines when the drain valve operator is to be
moved from a closed to an open position and then
returned to a closed position.
Brief Description of the Drawinqs
Figure 1 is a schematic flow diagram of a
pneumatic system which can incorporate the present
invention.
Figure 2 is a vertical cross-sectional view
of a unit incorporating features of the present
invention showing the control valve, the magnets,
and the discharge or drain valve and an operator.
Figure 3 i~ a plan view of a unit constructed
in accordance with the present invention taken at
right angles to the view shown in Figure 2.
Figure 4 is a fragmentary view of the pilot
or control valve and the float of the present
invention when the float is in the most downward
position and is about to rise due to accumulation
of condensable liquid in the reservoir.
Figure 5 is a fragmentary cross-sectional
view of the present invention as the float reaches
the uppermost position causing the reversal of the
polarity of the magnet mounted within the valve
plug.
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Figure 6 is a fragmentary cross-sectional
view of a control valve and float after the
reversal of the maynetic polarity and during the
downward movement of the float due to discharge of
accumulated liquid from the reservoir.
Figure 7 is a framentary cross-sectional view
of another embodiment of the lower portion of the
reservoir of the subject drain valve system.
Figure 8 is a schematic drawing further
illustrating the operation of the control valve of
the subject drain valve system.
Figures 9A and 9B are diagrammatic sectional
views of a further embodiment of an automatic
drain valve system constructed in accordance with
various features of the present invention.
Best Mode for CarryinqL-out the Invention
Refexring now to Figure 1, a schematic flow
diagram is shown for a pneumatic system u~ed to
operate the present invention. Air from a
pressurized source 10 is fed through line 11 to a
conventional filter lubricator 12 and thence
through line 13 to a regulator 14. The output
(e.g., 5 psi) from the regulator 14 feeds through
line 15 to the interior of proximity sensor tube
16. The tube 16 texminates in a valve seat 22.
Filtered pressurized air is also fed to a
multi-ported valve 17 through line 18. A typical
low pressure valve for this application is
Clippard Instrument Laboratory Model R-405. This
valve 17 has an operator 19 which consists of a
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piston 20 and a piston rod 21. The volurrle above
the piston 20 is connected by a line 23 to the
center of the proximity sensor tube 16 adjacent
the valve seat 22. Proximate the valve seat 22 is
a valve plug 26. This valve plug 26 i~ either in
contact with or displaced from the valve seat 22
by the method described hereinafter. As will be
described below, the proximity sensor tube 16 and
its valve seat 22 together with the valve plug 26
are contained within a separate closure 25.
External to the reservoir, in one embod1ment,
is a pneumatic cylinder 28 containing an
axially-movable piston 30 This piston 30 is
provided with a piston rod 32 extending through an
lS end of the cylinder 28, and the outward end of the
rod 32 is pivotally connec~ed to a discharge valve
operator arm 33 of valve 34. An inlet line 36 to
valve 34 connects to a reservoir to be drained
(not shown), and an outlet line 37 connects to any
appropriate drain or catch basin. The cyllnder 28
is provided with pneumatic lines 38, 40, one on
either side of piston 30 which lines are connected
to appropriate ports of the valve 17. The valve
17 is provided with vent lines 42, 43,
respectively connectable to lines 38, 40. Also,
enclosure 25 on the proximity valve com~onents is
provided with a vent line 44.
A cross-sectional view of the present device
for accumulating condensable materials and other
foreign matter from a pneumatic system, together
with means for draining the reservoir of this
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device, is shown in Figure 2 A separator/
reservoir 45 of this embodiment has a top housing
46 which is provided with an inlet 48 for
connection to any pneumatic or other yas system
from which condensate and foreign materials are to
be removed. Formed within the lower face of the
housing 46 is an arcuate channel 50 which serves
as a moisture condenser/filter as condensable
collect on the surface thereof. Depending from
below, the housiny 46 is a cylindrical shell or
sleeve 52 which forms the wall of the reservoir.
The bottom of the reservoir is formed from base
plate 56, and seals 58, 60 are inserted between
the shell 52 and the top housing and bottom plate,
respectively. Axial bolts or other means are
provided (see Figure 7) fo~ maintaining the sleeve
52 firmly clamped between the header 46 and the
bottom plate 56. This structure creates a
reservoir volume 54 as shown. The aforementioned
channel 50 communicates with this reservoir volume
54 whereby the volume 54 is used to collect the
condensate and other material that are removed
from the pneumatic system. Mounted within the
reservoir is a hollow cylinder 62 (corresponding
to eIement 25 of Figure 1) which is sealed to the
upper housing 46 with an appropriate seal 64 and
to the bottom plate 56 with an additionai seal 66.
Generally surrounding the cylinder 62 is a buoyant
member 68 which is slidable along the cylinder 62
from a top position wherein the top of the buoyant
member or float 68 i9 in contact with the under
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surface 47 of the housing 46, to a bottonl ~osition
wherein the bottom surface of the float 68 rests
against a float stop 70. l'he annular opening,
which is sufficient to minimize the collection of
foreign materials, wlthin the float 68 can be
provided with guides (not shown) to assist in the
movement of the float between its most distant
positions. Mounted within the top of the float or
proximate thereto is an annular magnet 72 (e.y., 2
x 1.3 x 1 in.) which encircles the cylinder 62.
Within the upper portion of the sleeve 62 is
a proximity or control valve 73 which consists of
a valve seat 74 and a valve plug 76 (equivalent to
elements 22, 24 of Figure 1). The valve plug 76
in turn consists of a cylindrical magnet 78 (e.g.,
O.B7 x 1 in.) encased in a protective layer 80.
The top of the plug 76 is provided with a
resilient cap or plug 82 for contact with the
valve seat 74. Positioned beneath the valve plug
76 is a cylindrical stop in the form of a hollow
cylinder 84, the purpose of which will be
described hereinafter in connection with the
relationships of the magnet 72 and 78. The stop
84 is provided with a central passageway 86 which
communicates with an outlet passage 88 (vent 44 of
Figure 1) through the base plate 56. Filtered air
is supplied to the interior of the pilot valve
seat 74 through a tube 90 from regulator 92,
Coaxially mounted within the pilot valve 73 is a
capillary tube 94 which communicates through
passageway 96 to a four way valve 98 ~the valve 17
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of Figure 1). Air is supplied to th~ va1ve 9B and
to the regulator 92 by mean~ of an inlet 102 and a
passageway 100. Although not shown in this
fi~uxe, the valve 9B communicates with additional
passageways in the header 46 for the purposes
described hereinafter.
Shown at the right of the Figure 1 is a drain
valve 34 and an operator system 106. This
operator system 106 is made up of the
aforementioned cylinder 28 which is attached to
the top header 46 with a clevis bracket 108. The
clevis bracket is mounted to the top header with a
pivot pin 110. Extending from the ~ottom of the
cylinder 2B is the aforementioned piston rod 32
which is pivotally connected to a valve operator
33 of valve 34 with a pin 112. The valve 36, in
turn, is connected to the bottom header 56 by a
fitting in the inlet line 36. The fitting
communicates with passageway 107 within the base
plate 56, with this passageway communicating with
a sump 109. The outlet from valve 34 leads
through conduit 37 to an appropriate collection
- vessel for the products drained from the
reservoir. Although not shown, pneumatic lines
for the operation of the piston within the
cylinder 28 are attached to the cylinder at ports
114 and 116. The purpose of these lines will be
described hereinafter.
A side elevational view of features of the
subject invention is shown in Figure 3. It may be
seen that the inlet port 114 at the top of
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cylinder 28 is connected by a ~neumatic ].ine 11~
(same as line 38 of Figure 1) to a port 120 which
communicates with the aforementioned valve 98
(Figure 2~. In a similar manner, the second port
116 at the bottom of cylinder 28 communicates
through a pneumatic line 122 (same as line 40 of
Figure 1) to a port 124 in the top of header 46
which, in turn, ls likewise connected to the valve
98. This figure also shows an optional liquld
level indicator line 126 which communicates with
an internal passageway 128 to the internal volume
54 of the reservoir.
Referring again to Figure 1, the pneumatic
operation of the subject invention can be
described with reference to this schematic
drawing. No~mally, pressurized air is fed from
source 10 or other appropriate source to the
filter and lubricator 12 and then to the proximity
valve 17 through corresponding lines 13 and 18.
This low pressure air is also admitted through
line 13 and regulator 14 into the internal volume
of the pilot valve seat 22 through line 15. When
the valve plug 26 is firmly seated against the
valve seat 22, the pressure existing in line 15
also exists in line 23 whi~h is connected to the
va].ve operator 19 of control valve 17. This
pressure in line 23 causes the piston 20 and
piston rod 21 to move the control valve 17 so as
to provide a pressure through line 40 to the
volume in cylinder 28 below the piston 30. At the
same time, the volume above the piston 30 in the
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cylinder 28 is connected through line 3~ to the
exhaust line 42. This results in maintaining the
piston 30 in an elevated position within the
cylinder 28 and thus the piston rod 32 moves the
valve operator 33 such that valve 34 is in a
closed position. Thus, the line 36 from the
reservoir ~ closed from the conduit 37. When,
however, the valve pluy 26 is displaced from the
valve seat 22 in a manner to be described
hereinafter, the air through line 15 entering the
valve seat 22 is exhausted through line 44. Under
these conditions, the pressure in line 23 is
substan~ially reduced. Thls causes the valve 17
to reverse the air flow to the cylinder 28.
Accordingly, air pressure is admitted to the
cylinder 28 through line 38 and the volume below
the piston 33 is exhausted through lin~ 40 and
vent line 43. This causes a downward movement of
the piston 30 and the pi~ton rod 32 which in turn
moves the valve operator 33 to fully open the
valve 34 thereby permitting full flow through line
36 to line 37 and thereby draining the reservoir.
When the reservoir is almost drained, the pilot or
control valve plug 26 again contacts the valve
seat 22 and thereby the initial condition occurs
whereby drain valve 34 is aqain closed,
maintaining a water seal and preventing compressed
air from escaping.
The operation of the pilot valve to
accomplish the opening and closing of the valve 34
can be understood by referring to Figures 4
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through 6. Referring to Fiyure 4, taken togethex
with Figure 2, the pilot valve is shown when the
float 68 is in its lowest position as established
by the float stop 70 (see Figure 2) or is rising
in the reservoir. The spacing of the float stop
70 and the valve plug stop 84 are such that
magnets 72 and 78 are always magnetically coupled
such that their normal reverse polarity (as
indicated) causes the valve plug 76 to be raised
firmly against seat 74 (or seat 74A ln Figures 9A
and B). Thus, the sealing member 82 is firmly
forced against the valve seat 74. As discussed
above, this maintains the drain valve 34 (see
Figure 2) in a closed position. As indicated, the
magnetic force F is in an upward direction in this
position.
Referring now to Figure 5, this illustrates
the float 68 in the most upward position; that is,
against the under surface of the header 46. When
in this position, the magnets 72 and 7B are
substantially aligned in height. The magnetic
field generated within magnet 72 causes an
effective reversal in the polarity of the magnetic
field within magnet 78. This effective reversal
is not instantaneous due to the hysterisis of the
magnet 78. However, when polaxity of the magnetic
field within magnet force F is effectively
directed downwardly whereby the valve plug 76 is
removed from the valve seat 74 to rest against the
stop 84. Air pressure within the valve seat 74 is
thereby released around the periphery of the valve
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plug 76 and is permitted to exit throuc3h channel
86 and passageway 88. As discussed above, thls
permits an opening of drain valve 34 whereby the
float 68 is lowered to the initial position as
shown in Figure 4. At the lowest position of
float 68 within the reservoir, the polarity of
magnet 78 is again effectively reversed bringing
about conditions whereby the valve plug 76 is
again forced against the valve seat 74. The
intermediate condit~on wherein the float is in an
elevated position, but dropping as the pilot valve
is opened, is illustrated in Figure 6. This same
magnetic coupling and polarity reversal occurs in
the operation of the unit shown in Figure 9 which
incorporates magnets 72' and 78'.
It will be recognized that the magnet
polarity reversal whlch occurs at the top and
bottom extreme travel of the float 68, and the
delay imparted by the hysterisis during this
reversal, operates the pilot valve in a "snap on"
and "snap off" manner. It is essential that the
pilot valve operate reliably whenever the float 68
reaches an exact position within the reservoir.
The particular construction shown in Figure 2 has
been found to provide this reliable operation.
The specific operation thereof can be explained in
more detail b~ reference to Figure 8. As
discussed above with reference to Figure 1, when
the valve plug 26 is in position such that its cap
82 is against the valve seat 22, regulated air
pressure entering through line 15 creates an ~qual
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pressure in capillary 23. This pressure within
capillary ~3 causes the piston 20 in control valve
operator 19 and the piston rod 21 attached thereto
to move the aforementioned control valve 17 (see
S Figure 1) in a direction to provide the needed air
pressure to the drain valve operator to maintain
the drain valve in the closed position.
However, when the valve plug 26 is rapidly
removed downwardly away from the valve seat 22 by
the operation of the aforementioned magnets, the
air flowing through line 15 is vented through the
valve seat 22. This venting of the air creates a
venturi action about the capillary 23 which causes
a rapid decrease of the pressure thereln. This
reduction of internal pressure within the
capillary 23 causes the ~iston 20 and the piston
rod 21 of the control valve operator to move
axially (downwardly in this Figure 8) so as to
move the control valve and reverse the application
of pressure to the drain valve operator. When the
valve plug 26 rises to fully contact the valve
seat 22, the pressure in capillary tube 23 is
substantially increased giving a positive action
of valve 17 and thus to the draln valve 34. This
combined rapid operation of the pilot valve and
the control valve operator 19 occurs at precise
times for each operation of the pilot valve and
thereby assures that the reservoir will not
overfill nor drain at a time prior to : ;,stantial
filling.
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The rapid and complete manner of operation of
the components is important to the operation of
the present invention for several reasons. The
main ~enefit of the rapid operation is in the
corresponding rapid operation of the piston within
the cylinder 28. The air supply provided to the
volume above the piston 30 through port 114 is
multiplied by the area of the piston whereby
considerable force is available to move the piston
rod 32 axlally away from cylinder 28, and the
connecting rod 33 rapidly operates valve 34 for
the draining of the reservoir. Through rapid
operation of this valve, full flow condition
exists ~uickly whereby all contents of the
reservoir are forced through valve by the pressure
of the pneumatic system tQ which the subject
invention is attached. This assures a rapid
removal of the contents of the reservoir brought
about by the pressure in the pneumatic system.
Again, when the reservoir is almost empty, the
valve 34 is rapidly closed thereby minimizing any
erosion of its components or the accumulation of
residual material exiting from the reservoir and
maintaining a liquid seal at all times. Since the
valve 34 is a rotary valve and power assisted, any
foreign material that may be present is cleared
from the surfaces and thereby cannot pr~vent the
valve from closing as in the case of an axially
moving valve.
Another embodiment of the reservoir portion
of the present invention is illustrated in Figure
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7. In this embodiment, the cylindrical wall 52 of
the reservoir is shortened such that the float
stop 70 ~see Figure 2) is not required.
Alternat~ly, the float 68 may be lengthened
accordingly such that the bottom plate 56 forms
the bottom stop for the float. This particular
construction has the advantage that when the float
68 reaches its lowermost travel, that is, against
the top of the bottom plate 56, the float closes
the opening of the sump 109. ~his closure of sump
109 further enhances the shut off of the fluid
flow out through passageway 107 and connector 36
leading to the drain valve (not shown). This
construction principally prevents air pressure
from leaving the reservoir prior to the automatic
closing of the rotary vaLYe. Shown also in Figure
7 are the typical bolts 128, 130, and the
respective nuts 132, 134 that are utilized for
holding the reservoir together.
A further embodiment of the automatic drain
valve of the present invention is illustrated
diagrammatically at 191 in Figures 9A and 9B.
~ertain components of the drain valve 191 which
are similar or comparable to components previously
described will be referred to by a common numerial
followed by an alphabetic character "A" or "B".
The drain valve 191 comprises a
separator/reservoir 45A provided with a top
housing 46A. As in the previously described
embodiment, depending from below the housing 46A
is a cylindrial shell or sleeve 52A which forms
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the side walls of the reservoir, and a base plate
56A forms the bottom of the reservoir, such
components being sealed and secured as described
hereinabove so as to define a reservoir volume
54A. An inlet 48A is provided in the base plate
56A for connecting to any pneumatic or any other
gas system from which condensate or other foreign
materials are to be removed, with the inlet 48A
communicating with the reservoir volume 54A by way
of the channel 50A. It will also be noted that a
further inlet port 48B and channel 50B can be
provided in the top housing 46A, if desired, and
when not in use, can be threadably closed with a
suitable bolt 49.
Mounted within the reservoir 45A is a
cylinder 62A having an upper end portion defining
a cavity 193, the cylinder 62A sealably engaging
the upper housing 46A. A bouyant member of float
68A surrounds the cylinder 62A and is slidable
along the length of cylinder 62A within the
reservoir volume 54A. Mounted within the top of
the float 68A or proximate thereto is an annular
maynet 72A which encircles the cylinder 62A. It
will be noted that the float 62A is provided with
protrusions 184 to prevent the float 68A from
adhering to the top housing 46A or the base plate
56A due to impurities s-lch as oil which can cause
a surface-to-surface bonding that would impede or
prevent the proper operation of the unit.
The drain valve 191 is provided with a
proximity or control valve 73A ~equivalent to the
valve 73 of Figure 2). The valve 73A comprises a
valve seat 74A and a valve plug 76A. The valve
plug 76A consists of a cylindrlcal magnet 78A
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encased in a protective layer as in the embodiment
of Figure 4. As illustrated in Figures 9A and 9B,
the top housing g6A defines an inlet 192
communicating with the cavity 193 through air
supply conduit 194. It will be appreciated that
pressuri~ed air is fed through the filter 196 and
inlet 192 from a pressurized source (not shown).
Further, the top houslng 46A further defines a
second air supply conduit 198 which establishes
fluid communication between the valve seat 74A and
an outlet 200.
As with the previous embodiment, a valve 34A
and an operator system 1 06A are also provided, the
operator system 1 06A comprising a cylinder 28A
which is attached to the top housing 46A with a
yolk mem~er 1 08A. Fluid communication between the
outlet 200 of the top housing 45A and the cylinder
28A is established through pneumatic line 11 8A,
and in the embodiment of Figures 9A and 9B, the
cylinder 28A slidably houses a piston 202 carrying
a downwardly extending piston rod 32A which is
pivotably connected to a valve operator 33A of
valve 34A. It will be noted that' the piston 202
is upwardly spring biased with a spring member
204, thus biasing the valve 34A to a closed
position, The base plate 56A is provided with an
outlet 206 communicating with the reservoir volume
54A through passageway 1 07A, and the valve 34A iS
connected in fluid communication with,the outlet
206 with a line 36A.
In~order to demonstrate the operation of the
drain valve 191, Fi~ure gA illustrates the
dlscharge valve 34A, and thus the drain valve 191,
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in a closed position, whereas, Figure 9~
illustrates the valve 34A in an open position with
condensate and other foreign materials being
drained from the reservoir 35A. Thus, with regard
to the operation of valve 191, as water and
condensate enter the reservoir volume 54A through
the inlet 48A (and/or the inlet 48B) connected
with the pneumatic system, the float 68A Will rise
causing the cylindrical magnet 78A to drop
proximate the position shown in Figure 9B, the
movement and positioning of the cylindrical magnet
78A being a result of interaction with the annular
magnet 72A as described hereinabove. The movement
of the valve plug 76A from the valve seat 74A
allows pressurized air fed into the cavity 193 by
air supply conduit 194 to yent from the cavity 193
through air supply conduit 198 and through
pneumatic line 11 8A to the cylinder 28A. With the
pressurized air being fed into the cy].inder 28A,
the piston 202 i5 forced downwardly overcoming the
bias of spring member 204, the piston rod 32A
ser~ing to manipulate the valve operator 33A such
that the discharge valve 34A i5 opened to allow
the condensate and water to drain from the
reservoir 45A. Accordingly, as the water and
condensate level lowers within the reservoir 45A,
the float 68A i5 lowered, once again assuming the
position illustrated in Figure 9A, the interaction
of the annular magnet 72A and the cylindrical
magnet 78A force the valve plug 76A upwardly to
sealably engage the valve seat 74A. Since the
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pressurized air is no longer vented from the
cavity 193 to the cylinder 28A, the spring member
204 biases the piston 202 upwardly and resultantly
the valve 34A to a closed position.
It will thus be appreciated that, whereas,
the automatic drain valve 191 functions much like
the previously described embodiment, the drain
valve 191 eliminates the need for four-way valve
98, regulator 14, and lubricator 12 of the
previous embodiment. This simplification of the
mechanism enhances reliability of the unit and at
the same time decreases manufacturing and
maintenance cost without sacrificing efficiency of
operation.
It is of course understood that although a
preferred embodiment of ~he present invention has
been illustrated and described, various
modifications thereof will become apparent to
those skilled in the art. Accordingly, the scope
of the invention should only be defined by the
appended claims and the equivalents thereof. For
example, the drain valve has been illustrated as
having a substantially conical cross-sectional
outline. It will, of course, be recognized that
this valve can assume various geometric
configurations, such as a half spherical shape.
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