U.S. patent number RE37,617 [Application Number 09/120,590] was granted by the patent office on 2002-04-02 for ball valve with integrated removable flow venturi, flow balancing means, and pipe union means.
Invention is credited to John C. Sherman.
United States Patent |
RE37,617 |
Sherman |
April 2, 2002 |
Ball valve with integrated removable flow venturi, flow balancing
means, and pipe union means
Abstract
A valve assembly for use in heating, ventilating and air
conditioning systems. The valve assembly includes a valve body
having a chamber in which is rotatably mounted a quarter-turn flow
control ball valve. A valve body nut having an outlet port is
threadably mounted on the valve body adjacent the outlet end of the
valve body chamber. A flow venturi is removably mounted in the
inlet end of the valve body. A pipe union tailpiece is detachably
mounted on the inlet end of the valve body. A pair of
pressure/temperature readout ports are mounted on the valve body
for use in determining the rate of fluid flow through the venturi.
A vent plug is mounted on the valve body for venting air from the
ball valve chamber.
Inventors: |
Sherman; John C. (Highland,
MI) |
Family
ID: |
23494508 |
Appl.
No.: |
09/120,590 |
Filed: |
July 9, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
378776 |
Jan 26, 1995 |
05533549 |
Jul 9, 1996 |
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Current U.S.
Class: |
137/557;
137/556.6; 251/118; 251/315.14; 73/861.63 |
Current CPC
Class: |
F16K
27/067 (20130101); G01F 1/44 (20130101); G01F
15/005 (20130101); Y10T 137/8326 (20150401); Y10T
137/8309 (20150401) |
Current International
Class: |
F16K
27/06 (20060101); G01F 1/34 (20060101); G01F
1/44 (20060101); G01F 15/00 (20060101); G01F
001/44 () |
Field of
Search: |
;251/315.14,118,288
;73/861.63 ;137/556,556.3,556.6,551,557 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chambers; A. Michael
Claims
What is claimed is:
1. In a valve assembly, the combination comprising:
(a) an elongated valve body (12) having an inlet end and an
elongated inlet bore (40,42);
(b) a flow venturi (62) removably mounted in said elongated inlet
bore (40,42), and having an inlet end with an entrance throat
passage (106) and an outlet end with an exit passage 108;
(c) a union tailpiece (44) detachably mounted on the inlet end of
the valve body (12), by a union nut (56), and having an inlet port
(58) formed therein;
(d) said elongated valve body (12) having a ball valve chamber (26)
formed therein, adjacent the venturi exit passage (108);
(e) a quarter-turn ball valve (22) rotatably mounted in said ball
valve chamber (26) for controlling the flow of fluid through the
valve body (12);
(f) a valve body nut (14) detachably mounted on the valve body
(12), adjacent the ball valve chamber (26), and having an outlet
port (20) formed therein;
(g) a first pressure/temperature readout port (82) detachably
mounted on said valve body (12);
(h) a first readout passage (80) formed in the valve body (12) and
communicating said first pressure/ temperature readout port (82)
with said elongated inlet bore (42) adjacent the inlet end of the
venturi (62);
(i) a second pressure/temperature readout port (82a) detachably
mounted on said valve body (12);
(j) a second readout passage (80a) formed in the valve body (12)
and communicating said second pressure/temperature readout port
(82a) with passage means (102,104) in the venturi (62) which
communicate with the venturi entrance throat passage (106);
(k) control lever means (124) attached to said ball valve (22) for
rotating the ball valve (22) between open and closed positions;
and,
(l) said pressure/temperature readout ports (82,82a) being adapted
to allow pressure and temperature detecting instruments to be
inserted throughout to provide the pressure and temperature
differences of fluid flowing into the venturi (62) and the fluid
flowing through the entrance throat passage (106) of the venturi
(62), for determining the rate of flow of fluid through the ball
valve (22) for setting the ball valve (22) in a selected open
position.
2. In a valve assembly, the combination as defined in claim 1,
comprising:
(a) a memory position stop (148) integrally formed on the valve
body (12); and,
(b) control lever memory position means (142,144, 150) adjustably
mounted on said valve stem (110) and including a stop leg (146)
engagable with the memory position stop (148) to restrict rotary
movement of the ball valve (22) to a selected open position.
3. In a valve assembly, the combination as defined in claim 2,
comprising:
(a) a position indicator plate (134) carried by said control lever
means (124); and,
(b) a position indicator means (152) on said control lever memory
position means (142,144,150) for indicating the adjusted open
position of the control lever means (124) when the stop leg (146)
engages the memory position stop (148).
4. In a valve assembly, the combination as defined in claim 3,
comprising:
(a) a vent plug hub (32) formed on the valve body (12) and having a
threaded vent plug bore (34) formed therein;
(b) a vent passage formed in the valve body (12) and communicating
the valve body chamber (26) with the vent plug bore (34); and,
(c) a removable vent plug (36) threadably mounted in said vent plug
bore (34) for venting air from said valve body chamber (26).
.Iadd.
5. In a valve assembly, the combination comprising:
an elongated valve body having an inlet end and an elongated inlet
bore;
a flow venturi removably mounted in said elongated inlet bore, and
having an inlet end with an entrance throat passage and an outlet
end with an exit passage;
said elongated valve body having a ball valve chamber formed
therein, adjacent the venturi exit passage;
a quarter-turn ball valve rotatably mounted in said ball valve
chamber for controlling the flow of fluid through the valve
body;
a first pressure/temperature readout port detachably mounted on
said valve body;
a first readout-passage formed in the valve body and communicating
said first pressure/temperature readout port with said elongated
inlet bore adjacent the inlet end of the venturi;
a second pressure/temperature readout port detachably mounted on
said valve body;
a second readout passage formed in the valve body and communicating
said second pressure/temperature readout port with passage means in
the venturi which communicate with the venturi entrance throat
passage;
control lever means attached to said ball valve for rotating the
ball valve between open and closed positions; and
said pressure/temperature readout ports being adapted to allow
pressure and temperature detecting instruments to be inserted
throughout to provide the pressure and temperature differences of
fluid flowing into the venturi and the fluid flowing through the
entrance throat passage of the venturi, for determining the rate of
flow of fluid through the ball valve for setting the ball valve in
a selected open position. .Iaddend..Iadd.
6. In a valve assembly, the combination as defined in claim 5,
comprising:
a memory position stop integrally formed on the valve body;
said control lever means comprising a rotary valve stem; and
control lever memory position means adjustably mounted on said
valve stem and including a stop leg engageable with said memory
position stop to restrict rotary movement of said ball valve to a
selected open position. .Iaddend..Iadd.
7. In a valve assembly, the combination as defined in claim 6,
comprising:
a position indicator plate carried by said control lever means;
and
a position indicator means on said control lever memory position
means for indicating the adjusted open position of the control
lever means when said stop leg engages said memory position stop.
.Iaddend..Iadd.
8. In a valve assembly, the combination as defined in claim 7,
comprising:
a vent plug hub formed on the valve body and having a threaded vent
plug bore formed therein;
a vent passage formed in the valve body and communicating said
valve body chamber with said vent plug bore; and
a removable vent plug threadably mounted in said vent plug bore for
venting air from said valve body chamber. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of art to which this invention pertains may be generally
located in the class of devices relating to valves. Class 137,
Fluid Handling, United States Patent Office Classification, appears
to be the applicable general area of art to which the subject
matter similar to this invention has been classified in the
past.
2. Description of the Prior Art
This invention relates to a flow control ball valve with an
integrated removable venturi, a flow balancing means, and a pipe
union means for use in a heating, ventilating and air conditioning
system. The integrated structure of the present invention combines
the most sought after components used in piping fan coils and air
handling units into a single compact, easy to install product.
Heating and cooling systems have widely varying flow rates
requiring different sized venturis to properly measure the flow
through the systems. Whenever a heating, ventilating and air
conditioning chilled water or hot water system is installed in a
facility, it employs terminal units such as fan coils, heat pumps,
air handlers or ventilating air coils to heat or cool the
individual spaces within the facility. To allow each coil to be
insulated, serviced, checked and balanced, a number of components
are used. These components include isolation valves, balance
valves, unions and pressure/temperature readout ports. Components
can, and are, used in virtually any combination. A typical job will
use a number of each of these components around every coil to
satisfy the requirements as stated on the plans for a system.
Unfortunately, these component combinations can become very
complex. A typical two-way coil piping schematic for a large
facility, for example, can contain over eight components and
fifteen pipe fittings which require over 26 piping connections to
complete. At ten minutes per piping connection, this works out to
over four hours to pipe up one coil. Multiply this by the fifty or
so coils on a normal job, and a labor requirement quickly runs up
into the hundreds of hours, and thousands of dollars of labor
costs.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a ball
valve which has integrated therewith a removable flow venturi, a
flow balancing means, a pipe union means, and an air vent tapping
plug, whereby the air collected in the body cavity of the valve can
be removed easily if the valve is employed in a fluid stream such
as a water stream.
It is another object of the present invention, to provide a ball
valve provided with a valve position indicator plate and an
adjustable memory position indicator stop member, and with an
integrated removable flow venturi and two associated pressure
temperature readout ports, whereby it is possible to satisfy the
requirements of a heating, ventilating and air conditioning system
with a minimum of valve bodies, at reduced installation labor costs
and provide a capability to customize each system by using various
combinations of venturis to effect a prebalancing of such a
system.
The flow venturi allows flow measurements to be taken through the
two pressure/temperature readout ports as fluid travels through the
valve, with the ball valve in an open position. Once the flow
measurement through the venturi is determined the ball valve can be
throttled, that is partially closed. Successive
pressure/temperature readings are then taken and the ball valve is
further throttled until the desired flow through the ball valve is
obtained. At that point the adjustable memory position indicator
stop member is set permit the ball valve to be closed and then be
reopened to the position of desired flow. The adjusted position of
the memory position indicator stop member relative to the valve
position the memory stop indicator plate is recorded for record
purposes.
Each one of the functions described hereinabove is typically
performed by a separate device in heating, ventilating, and air
conditioning systems. Each one of the functions requires at least
two piping connections, and every heat transfer coil installed to
heat and cool a given space within a building requires all these
devices to perform its function correctly. By combining all of
these separate devices into a single valve, considerable time is
saved in the installation of a heat transfer coil. In addition,
approximately ten piping connections are eliminated, thus removing
ten potential leak points. Also, the integrated ball valve of the
present invention is one fifth the installed length of the
components it replaces, making the installation of a heat transfer
coil much easier in what is typically a very cramped installation
space.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a ball valve with an integrated
removable venturi, a flow balancing means, a pipe union means, and
an air vent means, made in accordance with the principles of the
present invention.
FIG. 2 is a vertical section view of the ball valve illustrated in
FIG. 1, taken along the line 2--2 thereof, and looking in the
direction of the arrows.
FIG. 3 is a horizontal section view of the ball valve structure
illustrated in FIG. 2, taken along the line 3--3 thereof, and
looking in the direction of the arrows.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and in particular to FIGS. 1 and 2,
the numeral 10 generally designates a ball valve assembly including
a integrated removable venturi, a flow balancing means, and a pipe
union means. The integrated ball valve assembly 10 comprises a
valve body 12 that is provided on the exit end thereof with a valve
body nut 14. The inner end of the valve body nut 14 is circular in
shape and is provided with a peripheral threaded portion 16. The
peripheral threaded inner end 16 of the valve body nut 14 is
threadably mounted in the internally threaded valve body outlet end
18 of the valve body 12. The valve body nut 14 is provided with a
threaded outlet port 20. A flow control quarter-turn ball valve 22
is rotatably mounted in a ball valve chamber 26 in the valve body
12 on a pair of ball seals 24. The flow control quarter-turn ball
valve 22 is rotatably mounted about an axis perpendicular to the
longitudinal axis of the valve body 12. The valve body nut 14 is
provided with an inlet opening 28 on the inner end thereof, which
communicates with a passage 30 formed through the flow control ball
valve 22.
As shown in FIG. 3, the valve body 12 is provided with a
transverse, outwardly extended integral hub 32 which is positioned
centrally relative to the ball valve chamber 26. The hub 32 is
provided with an internal threaded plug bore 34 in which is
threadably mounted an air vent tapping plug 36. The inner end of
the vent plug bore 34 communicates with the ball valve chamber 26
by a transverse vent passage 38. The last described vent passage 38
and vent plug bore 34, provide an air removal passage. When the
valve ball 22 is in a partially open position, the valve ball
chamber 26 or cavity, between the ball valve 22 and the valve body
12 is open to fluid flow through the ball valve 22. Air traveling
in a water stream through the ball valve 22 will seek the point of
low velocity, which is the valve body chamber 26. The air collected
in the valve body chamber 26 may be removed easily by loosening the
air vent tapping plug 36.
The valve body 12 is provided with a stepped diameter, cylindrical
inlet passage which is aligned with the passage 30 formed through
the ball valve 22. The outer end of said stepped diameter,
cylindrical inlet passage is indicated by the numeral 42 and it is
formed to a diameter larger than the exit end thereof, which is
indicated by the numeral 40 and which is aligned with and
communicates with the passage 30 formed through the ball valve 22.
A union tailpiece 44 is detachably mounted on the inlet end of the
valve body 12. The inner end face 46 of the union tailpiece 44
seats against the face 48 of the inlet end of the valve body 12. An
O-ring seal 50 is operatively mounted in the face 48 of the inlet
end of the valve body 12, and it seats against the inner end face
46 of the union tailpiece 44. The union tailpiece 44 is provided
with a peripheral thread 52 on the inner end thereof around which
is threadably mounted the internal threaded portion 54 of a union
nut 56, for securing the union tailpiece 44 to the valve body 12.
The union tailpiece 44 is provided with an inlet port 58 which
communicates through an opening 60 in the inner end thereof with
the inlet end of the stepped diameter, cylindrical inlet passage
bore 42.
A venturi, generally indicated by the numeral 62 is slidably and
removably mounted in the stepped diameter, cylindrical inlet
passage 40,42. The inner end of the venturi 62 is formed with a
circular periphery 64 which is of a smaller diameter than the
diameter of the venturi outer end 66. An annular shoulder 68 is
formed around the periphery of the venturi 62 at the junction point
between the venturi outer peripheries 64,66. The venturi annular
shoulder 68 is seated against a mating shoulder 70 formed at the
junction point between the peripheries of the stepped cylindrical
passage inlet portions 40,42. The venturi 62 is releasably retained
in the valve body 12 by a removable retainer clip 74. The venturi
62 is provided around the periphery thereof, adjacent the entrance
end thereof, with a pair of longitudinally spaced apart O-ring
seals 72.
As shown in FIG. 1, an integral, cylindrical hub 76 is formed on
the valve body 12, in a position adjacent the inlet end of the
venturi 62, and on a transverse axis which is perpendicular to the
axis of the air vent hub 32. As shown in FIG. 2, the integral hub
76 is provided with a threaded bore 78 which extends inwardly from
the outer end thereof and which communicates at its inner end with
a transverse cylindrical passage 80 that is connected to the bore
42 of the stepped diameter, cylindrical inlet passage in the valve
body 12. The transverse cylindrical passage 80 is positioned to
communicate with the last mentioned passage bore 42 in a position
adjacent to the inlet end of the venturi 62.
Mounted in the threaded bore 78 of the integral hub 76 is a
conventional pressure/temperature readout port, which is identified
generally by the numeral 82. The conventional pressure/temperature
readout port 82 is available from Sisco, Inc. of 1700-B Industrial
Highway, Cinnaminson, N.J., 08077-2547, under Model Number BNO-250.
The pressure/ temperature readout port 82 includes an elongated
body 84 which has a threaded lower end 86 that is threadably seated
in the threaded bore 78 in the integral hub 76. An enlarged,
longitudinally extended bore or chamber 88 is formed in the
pressure/temperature readout port body 84 and it is open on the
lower end and communicates through a transverse cylindrical passage
80 with the inlet bore 42 in the valve body 12. An elastomeric
member 90, which is cylindrical in shape, is operatively mounted in
the bore 88, and its upper end is seated against the shoulder in
the readout body 84 formed by the upper end of the bore 88. The
lower end of the elastomeric cylindrical member 90 is seated on a
metal retainer tube 92 that is operatively seated in the lower end
of the readout port bore 88 and is retained in position by any
suitable means, as by a pressfit. The metal retainer tube 92
communicates at its lower end with the transverse cylindrical
passage 80 in the valve body 12. The body 84 of the pressure/
temperature readout port 82 is provided on the upper end thereof
with an integral reduced diameter extension 94, through which is
formed an axial, cylindrical passage 96 that communicates with the
upper end of the enlarged bore or chamber 88 in the readout port
body 84. The outer or upper end of the cylindrical passage 96, in
the upper end 94 of the readout body 84 of the readout port body
84, is enclosed by a seal 98 and a cap 100 threadably mounted on
the threaded upper end 94 of the readout body 84 when the readout
port 82 is inactive.
As shown in FIG. 1, a second pressure/temperature readout port is
mounted on the valve body 12, on a transverse axis which is
disposed 90 degrees to the transverse axis of the first readout
port 82, and it is indicated by the numeral 82a. As shown in FIG.
3, the second pressure/temperature readout port 82a is mounted in a
position for communication with a passage 80a which communicates
with the bore 42 of the stepped passage through the valve body 12,
and in a position which is perpendicular to the throat of the
venturi 62. As shown in FIG. 3, the parts of the second
pressure/temperature readout port 82a, which are the same as the
parts of the first pressure/temperature port 82, are marked with
the same reference numerals followed by the small letter "a". The
two pressure/temperature readout ports 82 and 82a are identical in
structure and use.
As shown in FIG. 3, the passage 80a that communicates with the
second pressure/temperature readout port 82, communicates at its
inner end with an annular or peripheral groove 102 that is formed
around the periphery of the throat of the venturi 62. The annular
or peripheral groove 102 formed around the venturi 62 communicates
at its inner end with a transverse cylindrical bore 104 that
communicates with the entrance or throat passage 106 of the venturi
62. As shown in FIG. 3, the venturi 62 is provided with a divergent
exit passage 108 that communicates with the cylindrical passage 40
in the valve body 12.
As shown in FIG. 2, the ball valve 22 is provided with a valve stem
or shaft 110 which has a lower integral rectangular end 112 that is
seated in a rectangular slot 114 that is formed in the upper end of
the ball valve 22. The valve stem or shaft 110 is rotatably mounted
in a valve stem hub 116 that is integrally formed on the valve body
12. The valve stem hub 116 is internally threaded and seated in the
inner end of the valve stem hub 116 is a conventional packing gland
118 which is held in an operative position in the valve stem hub
116 by a conventional packing gland nut 120. A pair of axially
spaced apart O-ring seals 122 are mounted around the periphery of
the valve stem or shaft 110 in sealing in engagement with the inner
bore of the packing gland nut 120.
As shown in FIGS. 1 and 2, a control lever, generally indicated by
the numeral 124, is provided for rotating the ball valve 22 between
a closed and an open position. As shown in FIG. 2, the control
lever 124 includes a handle portion 126 which is integrally
connected to a downwardly angled portion 128 that is integral with
a flat portion 130. The handle flat portion has an opening
therethrough for seating it around the threaded integral upper end
132 of the valve stem or shaft 110. A control lever position
indicator plate 134 has an opening therethrough to position it over
the integral threaded upper end 132 of the valve stem or shaft 110.
A control lever nut 136 is threadably mounted on the integral
threaded upper end 132 of the valve stem or shaft 110 and
releasably retains the flat portion 130 of the control lever 124
and the position indicator plate 134 in place. As shown in FIG. 2,
the flat portion 130 of the control lever 124 is provided on a free
end thereof, with an integral downwardly extended lip 138, which
engages an integral stop protrusion 140 on the hub 116, when the
control lever 124 is in the open position shown in FIGS. 1 and 2,
and the ball valve 22 is in a full flow position.
As shown in FIG. 1, the ball valve 22 is provided with a memory
position indicator circular cap member 142 which is provided with
an outwardly integral extension 144 on one side thereof. An
integral downwardly extended memory position stop leg 146 (FIG. 2)
is integrally formed on the memory position cap extension 144. A
vertical, integral stop 148 (FIG. 1) is formed on the valve body
12, and it extends upwardly therefrom, and is adapted to be engaged
by the memory position stop leg 146, as described hereinafter. A
retainer bolt 150 is mounted through an opening in the top wall of
the memory position cap member 142, and it extends downwardly into
a threaded hole in the upper end of the valve stem 132 for securing
the memory position cap member 142 in a rotated position relative
to the valve stem 110. As shown in FIG. 1, the memory position cap
member 142 is provided with an integral protrusion 152 on the side
thereof to show the position of the memory position cap 142 in an
adjusted position relative to the percentage degree of valve
opening on the position indicator plate 134.
In use, the ball valve, with the integrated removable flow venturi,
with the flow balancing means is operatively mounted in a fluid
flow line of a heating, ventilating and air conditioning system by
means of the valve body nut 14 and the union tailpiece 44 and union
nut 56. The flow ball valve flow control handle 124 for the ball
valve 22 is shown in FIGS. 1 and 2 in an open valve position. The
ball valve 22 may be turned to a fully closed position by rotating
the control handle 124 through a 90 degree turn, in a clockwise
direction, as view in FIG. 1.
Heating and cooling systems in large buildings have a plurality of
circuits with widely varying flow rates, that require different
size venturis to properly measure the flow through a fluid flow
control valve. By providing a removable venturi it is possible to
satisfy the requirements of the heating and cooling industry with a
minimum of valve bodies. Furthermore, it is possible to customize
each installation by using various sizes of flow venturis for the
various flow valves incorporated in a heating and cooling system,
and thus provide a means for prebalancing the flow of fluid through
a plurality of valves in a heating and cooling system.
As shown in FIG. 1, when the ball valve control lever 124 is in the
full flow or 100% flow position, the memory position stop leg 146
and the memory position indicator circular cap member 142 are
releasably secured on the valve stem 110 in a position shown in
FIG. 1, so that the stop leg 146 abuts the stop member 148. In this
condition, the ball valve control lever 124 may be rotated 90
degrees between the open position shown in FIG. 1 and a closed
position. However, in a heating and cooling system it is necessary
to regulate the flow of fluid through the ball valve 22. For
example, in a water flow line it may be desirable to provide a
certain volume flow, as for example, four gallons of fluid per
minute.
In order to set the control lever 124 for a desired flow, the caps
100 and 100a on the pressure/temperature readout ports 82 and 82a
are removed. Conventional pressure and temperature needle type
instruments are then used to determine the pressure drop across the
throat of the venturi 82. The pressure and temperature needle type
instruments are provided with the pressure/temperature readout
ports 82 and 82a, by the manufacturer of the same, who is listed
hereinbefore. A needle type pressure instrument is inserted
downwardly through each of the passages 96 and 96a, in the readout
ports 82 and 82a, respectively, and through the elastomeric members
90 and 90a, and into the bores 42 and the throat portion 106 of the
venturi 62. Such instruments have pressure indicating instruments
attached thereto as for example, manometers. Temperature difference
readings of the fluid flowing through the venturi 62 are also
obtained by temperature needle instruments inserted downwardly
through the readout ports 82 and 82a. The pressure and temperature
differences between the pressure and temperature readings obtained
through the readout ports 82 and 82a are then compared to a flow
calibration chart for the particular venturi 62 which is being used
and the calibration chart for such a venturi 62 employed. If the
calibration chart for the particular venturi indicates that a four
inch pressure differential, and the temperature difference
obtained, results in seven gallons of fluid per minute through the
particular venturi 62, the user will throttle the ball valve
control lever 124, that is move it in a clockwise direction as
viewed in FIG. 1 to reduce the flow of fluid through the ball valve
22.
Successive pressure and temperature differential readings are taken
together with successive throttling movements of the ball valve
control lever 124 until the desired flow through the venturi is
reached, as for example, the aforestated four gallons per minute.
At that point, the retainer bolt 150 is loosened, and the memory
position cap member 142 is rotated counter clockwise, as viewed in
FIG. 1, to bring the memory position stop leg 146 into engagement
with the integral vertical stop 148. The retainer bolt 150 is then
secured in place, to lock the position of the memory position stop
leg 146 in its adjusted position. The differential pressure and
temperature which provides the desired volume of fluid flow through
the venturi 62 is recorded, and the setting of the position
indicator protrusion 152 on the memory position cap 142, relative
to the percentage valve open position it is adjacent to on the
position indicator plate 134 is also recorded. It will be seen,
that after the aforedescribed balancing steps have been carried
out, it is possible to move the ball valve control lever 124
clockwise, as viewed in FIG. 1, to a fully closed position, and it
may thereafter be turned counterclockwise back to the desired and
preset flow position, because the stop leg 146 will engage the stop
148 and prevent the control lever 124 from being moved further in a
counterclockwise direction.
* * * * *