U.S. patent number 3,624,753 [Application Number 05/032,267] was granted by the patent office on 1971-11-30 for two-stage opening valve.
This patent grant is currently assigned to Grove Valve and Regulator Company. Invention is credited to Richard S. Brumm.
United States Patent |
3,624,753 |
Brumm |
November 30, 1971 |
TWO-STAGE OPENING VALVE
Abstract
A two-stage opening globe valve including the main valve member
with a chamber therein receiving the valve stem to permit limited
relative axial movement between them. Coaxial and lateral primer
ducts connect the chamber to the upstream and downstream flow
passages, and on the end of the stem is a primer valve that opens
and closes the coaxial duct. When the stem is moved to open the
valve it opens the primer valve first while an imbalance in
opposing areas of the main valve closure which are exposed to
upstream pressure produces a force differential biasing the valve
toward closed position.
Inventors: |
Brumm; Richard S. (Orinda,
CA) |
Assignee: |
Grove Valve and Regulator
Company (Oakland, CA)
|
Family
ID: |
21864010 |
Appl.
No.: |
05/032,267 |
Filed: |
April 27, 1970 |
Current U.S.
Class: |
137/630.14 |
Current CPC
Class: |
F16K
39/024 (20130101); Y10T 137/86976 (20150401) |
Current International
Class: |
F16K
39/00 (20060101); F16K 39/02 (20060101); F16k
001/02 () |
Field of
Search: |
;137/630.13,630.14,630.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nilson; Robert G.
Claims
What is claimed is:
1. In a valve construction comprising:
a valve body,
inlet and outlet flow passages in said valve body,
a valve seat surface around one of said flow passages,
a valve closure movable axially into sealing engagement with said
seat surface, and
a stem movable axially for operating said valve closure,
the improvement comprising:
a closed fluid chamber in said valve closure,
a coaxial primer port in said valve closure connecting said chamber
with said one flow passage,
a second port connecting said chamber with the other flow
passage,
a primer valve member on said stem and received in said chamber for
limited axial movement relative to said valve closure to close and
open said coaxial port,
a coaxial bore in said valve closure opening to said chamber,
said stem being slidably received in said coaxial bore, and
means sealing said bore around said stem,
said bore being opposite to and larger than said coaxial primer
port whereby there is a larger area within said chamber exposed to
pressure therein in a direction toward said port.
2. The valve construction defined by claim 1 including:
a bore in said valve body receiving said valve closure,
said other flow passage opening into said bore at one end thereof
adjacent said valve seat,
means sealing around said stem at the other end of said bore,
means sealing around said valve closure intermediate said other
flow passage and said other end, and
a balancing duct connecting said other end of the bore and said one
flow passage.
3. The valve construction defined by claim 2 including:
a larger counterbore at said one end of the bore,
said valve closure being of complementary, stepped cylindrical
configuration slidably received in said bore and counterbore,
said bore and valve closure presenting opposing radial shoulders,
and
a seal ring received in said space to seal between the small
diameter portion of said cylindrical closure and the wall of the
large counterbore.
4. The valve construction defined by claim 3 wherein:
said valve closure seals against said valve seat on a diameter
intermediate that of said small diameter portion and said
counterbore.
5. The valve construction defined by claim 2 including:
a radial shoulder and stepped cylindrical surfaces on said valve
closure,
complementary stepped cylindrical stationary surfaces forming with
the valve closure an annular chamber between concentric cylindrical
surfaces,
a seal ring sealing between said concentric surfaces,
the diameters of said concentric surfaces being selected relative
to the sealing diameter of the valve closure sealing engagement
with said seat surface that the net area acted on by fluid biasing
said valve closure toward said seat surface is greater than the net
area acted on in a direction biasing the valve closure away from
said seat surface irrespective of the direction of pressure
differential.
Description
BACKGROUND OF THE INVENTION
This invention relates to a two-stage opening valve and more
particularly to a valve in which full capacity flow is normally
delayed until upstream and downstream pressures are substantially
equalized through a primer duct.
When a valve is opened to high-pressure differentials, the
resultant sudden surge of high-velocity flow can cause severe
erosion damage to the valve and may score or blow out a resilient
seal ring. Moreover, when air or some other gas containing oxygen
is being transmitted, the sudden rapid compression of the gas in
the downstream line when the valve is opened may cause the gas to
reach a dangerously high temperature level before heat can be
dissipated. In the event a combustible is in the line or in the
seal material, the sudden heat rise may cause a fire, or even an
explosion.
Certain fluid systems have been designed to overcome this problem
by providing a low capacity bypass line with a small valve which
may be opened first to allow a low capacity flow around the main
valve which causes downstream pressure to build up gradually. Then
when upstream and downstream pressures are nearly equal, the main
valve may be opened for full flow. However, such systems suffer the
infirmities of the human factor, in that they are dependent upon
the operator remembering the sequence of operation. Under certain
hazardous circumstances, a single neglectful operation could
produce devastating results.
OBJECTS OF THE INVENTION
It is, therefore, an object of this invention to provide a
two-stage opening valve wherein the main valve remains closed if
desired until throttled flow through a primer valve equalizes
pressure.
It is a further object of this invention to provide a two-stage
opening valve wherein opening of the main valve is resisted until a
primer valve has equalized pressure.
It is a further object of this invention to provide a two-stage
opening valve wherein the main valve is biased closed until a
primer valve equalizes pressure.
It is a further object of this invention to provide a two-stage
operating valve wherein a primer valve operates to equalize
pressure before operation of the main valve regardless of the
direction of pressure differential.
Other objects and advantages of this invention will become apparent
from the detailed description to follow.
BRIEF SUMMARY OF THE INVENTION
In carrying out this invention, I provide a cylindrical globe valve
member in a complementary bore. There is a chamber in the valve
plug into which the valve operating stem extends with a limited
amount of relative axial movement permitted between the stem and
the valve member. A primer valve on the end of the stem uncovers a
coaxial primer duct, connecting the chamber to a flow passage
during initial operation of the valve stem. A second primer duct
connects the chamber with the other flow passage so that fluid from
the upstream passage flows at throttled rate to the downstream. In
one embodiment of the invention, the bore in the main valve through
which the stem extends is much larger than the coaxial outlet
primer duct so that with a seal around the stem there is a greater
area on the outlet side of the chamber exposed to upstream
pressure, whereby the resultant force urges the valve closure
toward its seat. Hence, the main valve is biased closed as the
primer valve is opened by initial movement of the valve stem.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view of a valve embodying features of this
invention mounted in a housing; and
FIGS. 2, 3 and 4 are partial section views showing other
embodiments of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The Embodiment of FIG. 1
Referring now more particularly to FIG. 1, the valve 10 of this
invention is shown on a housing block 12 which is bored to provide
inlet and outlet flow passage 14 and 16. A subassembly sleeve 18
forming part of the valve is received in a bore 20 in the housing
block 12 with an O-ring 22 sealing around the upper portion thereof
to prevent leakage.
A pin 24 locates the sleeve 18 with respect to the body block 26
and a second pin 28 locates the body block 26 with respect to the
housing block 12 to insure alignment of the inlet port 30 with the
upstream flow passage 14. When so retained, the body block is
secured in place, as by means of capscrews 32.
Threadedly received in an upright cylindrical extension 33 of the
body block 26 is stem screw 34 to which is fixed as by means of a
setscrew 36 engaging a flat portion thereon is a handwheel 40
rotatably received on the upstanding cylinder portion 33. Formed on
the lower end of the stem screw 34 is a receptacle 42 which
receives the head portion 44 of a valve stem 46. A bearing member
48 having low friction characteristics is interposed between the
receptacle 42 and the head 44 of the valve stem to minimize
transmission of rotation from the threaded stem. A snapring 50 may
be provided to retain the head 44 of the lower stem 46 in the
receptacle 42. The lower stem 46 is slidably received in a bearing
member 52 with an O-ring 54 sealing around it. The O-ring may be
retained as by means of a low friction bearing ring 56 and a
snapring 58, with an O-ring 60 being provided to seal around the
bearing member 52.
Carried on a shoulder 62 formed at the lower end of a counterbore
64 is a seat ring retainer 66 of fairly rigid material
substantially enclosing a seat ring of suitable plastic material,
to prevent extrusion of the seat ring material into the flow line
16. An O-ring 70 is provided to insure against leakage around the
seat ring 68. An annular lip 72 around the lower end of the main
valve plug 74 seals against the seat ring 68 when the main valve is
in its closed position as shown in FIG. 1.
Secured to the lower end of the valve stem 46 is an enlarged head
76 forming the primer plug, with an O-ring 78 sealing a trailing
portion thereof 80 within a slide-bearing member 82 that is
threaded into the main valve plug 74. A coil spring 84 may be
provided to bias the main valve plug 74 away from the primer valve
76 and into its closed position, and a shoulder 86 will transmit
upward movement of the primer valve 76 to the main valve plug 74
after limited relative movement of the primer valve away from its
seat 88. A ring 89 of Teflon or the like, backed up by an O-ring 90
seals around the main valve plug 74.
The primer valve 76 when in the closed position shown in FIG. 1
engages the pilot valve seat to shut off an outlet primer duct 91
opening into the downstream flow passage. A second primer duct 92
brings the chamber 94 in communication with the upstream flow
passage 14. The upstream pressure within the chamber 94 acts on the
bottom surface thereof over the full area, i.e., the area of a
circle of the bore diameter less the area of the primer duct 91.
That same pressure acts against the top of the chamber only to the
extent permitted by the O-ring seal 78 around the trailing portion
88 of the primer plug 76, i.e., the area of the annular lower end
of the slide bearing 82. Hence, There is a substantially greater
area which is exposed to upstream pressure in a direction forcing
the main valve plug 74 toward the seat ring 68, and there is
considerable resistance to opening the main valve.
In operation, the handwheel 40 is turned just enough to lift the
primer valve 76 from its seat 88 with the shoulder 86 out of
engagement with the slide bearing 82. The upstream pressure in the
chamber 94 will hold the main valve plug 74 against its seat 68 as
the upstream pressure passing through the restricted primer valve
passage 91 builds up pressure in the downstream line 16. Then, when
the upstream and downstream pressures are substantially balanced,
the operator may again turn the handwheel 40 to lift the stem 46
whereby the shoulder 86 on the primer valve 76 will engage and open
the main valve plug 76 for full capacity upstream flow. A bypass
passage 96 through the main valve plug 74 maintains the cavity 98
above the main valve 74 at the level of the downstream pressure in
order to prevent a high-pressure drop across the main valve which
would generate high forces against the valve stem 46, and to
prevent the entrapment and build up of pressure as the valve is
opened.
The Embodiment of FIG. 2
Referring now to FIG. 2, the primer valve 100 may be provided with
a bypass passageway 102 which permits venting of the cavity 98 by
flowing through the threads 104 around the stem 46. In this case,
the primer valve 100 is preferably provided with a nose 106
extending into the primer duct 108 so that a low-pressure area will
not be created in front of the primer valve 100 as a result of the
vacuum caused by high velocity flow past the bypass duct 102.
The Embodiment of FIG. 3
Referring now to the embodiment of FIG. 3, the main valve plug 110
is biased toward the seat 68 regardless of the direction of
pressure differential. For this purpose, the subassembly 112 is
provided with a counterbore 114 and the main valve plug has a
reduced diameter trailing portion 116, forming a stepped
configuration. Between opposed shoulder 118 and 120 on the
subassembly sleeve 112 and on the main valve plug 110 is an O-ring
122 sealing between the concentric cylindrical surfaces 114 and
116. The sealing lip 124 on the main valve plug is of a sealing
diameter intermediate that of the two cylindrical surfaces 114 and
116.
Assuming that passage on the left is the upstream passage, pressure
acts around the main valve plug 110 to force the O-ring 122 up
toward the shoulder 118 on the subassembly and asserts a downward
force against the valve plug shoulder 120 over its full annular
area. On the bottom of the plug it asserts an upward force, but
does not act inward beyond the seal diameter, somewhere on the face
of the seal lip 124 which is of a diameter greater than that of the
smaller cylindrical surface 116. Within the chamber, the area of
the bottom surface thereof 119 is greater than that of the top 121,
so that, again, there is a difference in force. Therefore, with the
upstream pressure coming from the left passage 14 the net force
will tend to bias the main valve plug 110 against the seat 68.
If the lower passage is made the upstream passageway, pressure
forces asserted through the bypass duct 125 and back around the
valve plug, act downward to force the O-ring 122 and the primer
valve tail O-ring 126 down in their recesses so that the pressure
acts over an annular area between the inner O-ring recess, i.e.,
the diameter of the primer valve engaged by the O-ring 126 and the
diameter of the larger bore 114. On the bottom of the valve, the
pressure acts upward over the annular area between the primer port
91 and the main seal circular lip. Hence, downward force is
unopposed between the bore diameter 114 and the main seal 124 while
upward force is unopposed between the inner diameter of primer
valve O-ring 126 and the primer port diameter. Hence, the diameters
are established so that the first annular area described is the
greater. This can be done without difficulty because the larger
diameters produce greater differences in area per unit of diameter
variance.
In either instance, without regard to the direction of pressure
differential, the net force biases the plug 110 in its closed
position until line pressure has been substantially equalized
following opening of the pilot valve. Thereafter, the operator may
continue rotation of the handwheel to open the main valve 110.
The Embodiment of FIG. 4
Referring now to FIG. 4, the main valve plug 130 is biased against
its seat by means of a powerful spring 132. In this instance
operation of the valve stem 46 is not opposed until the shoulder
134 on the primer valve 136 engages against the bearing member 138.
Thereafter, operation will be more difficult, and the resistance to
operation will serve as a signal to the operator to postpone
operation until pressure has had an opportunity to equalize.
While this invention has been described in conjunction with
preferred embodiments thereof, it is obvious that modifications and
changes may be made by those skilled in the art without departing
from the spirit and scope of this invention.
* * * * *