Radial flow diaphragm valve

A valve arranged for radial fluid flow from its inlet to its outlet has a spring-loaded diaphragm covering a valve cage member having a central opening communicating with the valve inlet surrounded by a plurality of peripheral openings communicating with the valve outlet. The valve cage member is downwardly concave and a valve top member closing off the valve body has an upwardly concave surface which is substantially the inverse of the concave surface of the valve cage member. Accordingly, the diaphragm moves from a zero flow configuration against the valve cage member to a full flow configuration against the valve top member symmetrically without stretching.

BACKGROUND OF THE INVENTION 
This invention relates to valves and, more particularly, to an improved 
diaphragm valve for regulating gas flow, wherein movement of the flexible 
diaphragm between zero flow configuration and a full flow configuration is 
effected without stretching the diaphragm. 
Current devices for regulating fluid flow include throttling devices with 
orifices and valves actuated by lever mechanisms and pan-type rubber 
diaphragms to vary the orifice opening. These devices rely on the 
principle of equilibrium of forces to control pressure and suffer from 
elevated pressure effects, i.e., the outlet pressure varies as a function 
of the inlet pressure. Also, fluid flow capacities are restricted by the 
size of the orifice, which in turn is limited to the available shut off 
force. 
Other devices employ slotted cages and molded rubber sleeves (or boots) 
that peel from the cage slots to throttle fluid flow. Sleeve and boot-type 
valves each have limitations. These valves have poor stability at low 
fluid flow rates through the valve. The fluid stream usually impinges 
substantially on the sleeve and deflects the fluid stream, thereby 
subjecting the sleeve to erosion. Other difficulties encountered are 
stretching and extrusion of the rubber sleeves as well as difficulties in 
the assembly, operation and use of such prior valves. 
It is therefore apparent that a need exists for a fluid flow regulating 
valve which does not suffer from the above-enumerated deficiencies. A need 
also exists for such a valve which is easily serviced, without requiring 
removal of the entire valve from the pipeline in which it is installed. 
SUMMARY OF THE INVENTION 
The foregoing and additional objects are attained by providing a valve 
having a valve body with inlet and outlet ends, a top wall between the 
inlet and outlet ends and a valve chamber open to the top wall. An inlet 
passage, open to the inlet end and the valve chamber, and an outlet 
passage, open to the valve chamber and the outlet end, extend through the 
valve body. The outlet passage at least partially surrounds the inlet 
passage where the inlet and outlet passages open to the valve chamber. The 
valve also includes a generally disc-like valve cage member disposed in 
the valve chamber and overlying the openings of the inlet and outlet 
passages to the valve chamber. The valve cage member has a central opening 
in registration with the inlet passage opening and a plurality of 
peripheral openings surrounding the central opening and in registration 
with the outlet passage opening. A portion of the upper surface of the 
valve cage member opposite the openings of the inlet and outlet passages 
is generally concave and tapers upwardly from the central opening past the 
plurality of peripheral openings. A flexible diaphragm within the valve 
chamber overlies the valve cage member so as to cover the central opening 
and the plurality of peripheral openings. A valve top member is mounted to 
the valve body top wall over the valve chamber. The valve top member 
engages the periphery of the diaphragm to capture and sealingly engage the 
diaphragm periphery between the valve top member and the valve cage 
member. The valve top member is formed with an internal control chamber 
overlying the valve chamber. A spring is disposed in the control chamber 
and engages the valve top member and the diaphragm so as to yieldably bias 
the diaphragm into sealing contact with the valve cage member and prevent 
fluid flow from the inlet passage to the outlet passage through the 
central opening and the plurality of peripheral openings of the valve cage 
member. A channel through the valve top member provides fluid 
communication to the control chamber. 
In accordance with an aspect of this invention, the central opening of the 
valve cage member is circular and each of the plurality of peripheral 
openings of the valve cage member comprises an elongated slot extending 
along a radius of the central opening. 
In accordance with another aspect of this invention, the opening of the 
inlet passage to the valve chamber is circular and the opening of the 
output passage to the valve chamber is annular and concentric with the 
opening of the inlet passage to the valve chamber. 
In accordance with a further aspect of this invention, the control chamber 
of the valve top member includes a surface opposite the upper surface 
portion of the valve cage member which is substantially the inverse of the 
upper surface portion of the valve cage member. Accordingly, the diaphragm 
can move symmetrically without elongation from a zero flow configuration 
in contact with the upper surface portion of the valve cage member to a 
full flow configuration in contact with the control chamber surface.

DETAILED DESCRIPTION 
Referring now to the drawings, FIG. 1 shows an improved diaphragm valve, 
designated generally by the reference numeral 20, constructed according to 
the present invention. Major components of the valve 20 include the valve 
body 22, the valve cage member 24, the diaphragm 26, the valve top member 
28 and the spring 30. As shown, the valve body 22 has an inlet end 32 and 
an outlet end 34. Parallel flanges 36, 38 at the inlet and outlet ends, 
respectively, are used for installing the valve 20 in a pipeline, as is 
conventional. The valve body 22 also has a top wall 40 between the inlet 
and outlet ends 32, 34. A valve chamber 42 open to the top wall 40 is 
formed in the valve body 22. Preferably, the top wall 40 is planar and 
orthogonal to the flanges 36, 38 and the valve chamber 42 is circular in 
section parallel to the top wall 40. 
The valve body 22 is further formed with an internal inlet passage 44 
extending through the valve body 22 and open to the inlet end 32 and the 
valve chamber 42. As shown, between the inlet end 32 and the valve chamber 
42, the inlet passage 44 makes a 90.degree. turn with smooth area 
transitions to reduce the flow turbulence. Preferably, the inlet passage 
opening 46 to the valve chamber 42 is circular, as is the opening of the 
inlet passage 44 to the inlet end 32. Further, the inlet passage 44 is 
preferably circular in cross section along its length orthogonal to the 
flow line 48. The valve body 22 is also formed with an internal outlet 
passage 50 which is open to the outlet end 34 and the valve chamber 42. 
The opening of the outlet passage to the outlet end 34 is preferably 
circular and shares a common centerline 52 with the opening of the inlet 
passage 44 to the inlet end 32. The outlet passage 50 at least partially 
surrounds the inlet passage 44 where the inlet and outlet passages open to 
the valve chamber 42. Preferably, as best seen in FIG. 5, the opening 54 
of the outlet passage 50 to the valve chamber 42 is annular and concentric 
with the opening 46 of the inlet passage 44 to the valve chamber 42. The 
opening 46 of the inlet passage 44 to the valve chamber 42 and the opening 
54 of the outlet passage 50 to the valve chamber 42 share a common 
centerline 55 which is orthogonal to the centerline 52. 
The valve cage member 24 is disposed in the valve chamber 42 overlying the 
openings 46, 54 of the inlet and outlet passages, respectively, into the 
valve chamber. As shown, the valve cage member 24 is generally disc-like 
and is formed with a central opening 56 and a plurality of peripheral 
openings 58. The central opening 56 is in registration with the opening 46 
of the inlet passage 44 into the valve chamber 42 and preferably is 
generally circular. The peripheral openings 58 surround the central 
opening 56 and are in registration with the opening 54 of the outlet 
passage 50 into the valve chamber 42. Preferably, each of the peripheral 
openings 58 is an elongated slot extending along a radius of the central 
opening 56. For full flow, the total area of all of the plurality of 
peripheral openings 58 must be at least equal to the area of the central 
opening 56. 
As best shown in FIG. 7, the valve cage member 24 has a portion 60 of its 
upper surface which tapers upwardly from the central opening 56 past the 
plurality of peripheral openings 58 so as to be generally concave. The 
lower surface 62 of the valve cage member 24 is formed with a first 
annular groove 64 surrounding the central opening 56 and inward of the 
plurality of peripheral openings 58 and a second annular groove 66 
surrounding the peripheral openings 58. A first seal ring 68 is disposed 
in the groove 64 and a second seal ring 70 is disposed in the groove 66. 
As shown in FIG. 1, the seal ring 68 surrounds the opening 50 of the inlet 
passage 44 into the valve chamber 42 and is between the valve body 22 and 
the valve cage member 24, and the seal ring 70 surrounds the opening 54 of 
the outlet passage 50 into the valve chamber 42 and is between the valve 
body 22 and the valve cage member 24. 
The diaphragm 26 overlies the valve cage member 24 to cover the central 
opening 56 and the peripheral openings 58. In plan, the diaphragm 26 is 
circular, having a circumferential flange 72 sized to fit within the 
annular channel 74 at the periphery of the valve cage member 24. At its 
center, the diaphragm 26 is formed on its lower surface with a generally 
conical projection 76 which extends into the central opening 56 of the 
valve cage member 24. Moving outwardly from the central conical projection 
76, the lower surface 78 of the diaphragm 26 is complemental to the upper 
surface portion 60 of the valve cage member 24 in the region of the valve 
cage member 24 extending from the periphery of the central opening 56 past 
the plurality of peripheral openings 58. Accordingly, as best shown in 
FIGS. 1 and 2, when unstressed the lower surface 78 of the diaphragm 26 
engages the upper surface portion 60 of the valve cage member 24 
surrounding the plurality of peripheral openings 58 so as to seal the 
peripheral openings 58 as well as the central opening 56. Opposite the 
conical projection 76, the upper surface 80 of the diaphragm 26 is formed 
with a circular cavity 82 in which is disposed a rigid spring cup 84. The 
spring cup 84 has a central cavity 86 for containing therein the spring 
30, as will be described. 
The valve chamber 42 is sealed by the valve top member 28 which is mounted 
to the top wall 40, illustratively by bolts 88 which extend through 
suitable holes in the top member 28 and into threaded holes 90 in the 
valve body 22. The valve top member 28 is formed with a circumferential 
channel 92 which holds the circumferential flange 72 of the diaphragm 26. 
Thus, the valve top member 28 captures the periphery of the diaphragm 26 
between the valve top member 28 and the valve cage member 24 and effects a 
seal. The valve top member 28 is further formed with an internal control 
chamber 94 which overlies the valve chamber 42. The control chamber 94 is 
circular in section orthogonal to the centerline 55. At its lower end, the 
control chamber 94 is defined by a surface 96 which is substantially the 
inverse of the upper surface portion 60 of the valve cage member 24. The 
upper region 98 of the control chamber 94 is cylindrical, concentric with 
the centerline 55. The spring 30 is preferably a helical compression 
spring which is within the cylindrical upper region 98 of the control 
chamber 94. The upper end of the spring 30 engages the upper wall 100 of 
the control chamber 94 and the lower end of the spring 30 is contained 
within the spring cup 84. Accordingly, the spring 30 yieldably biases the 
diaphragm 26 downwardly into sealing contact with the valve cage member 
24. 
As is known, flow from the inlet passage 44 to the outlet passage 50 is 
controlled by regulating the pressure differential across the diaphragm 26 
between the inlet passage 44 and the control chamber 94, this pressure 
differential acting against the force of the spring 30 to unseat the 
diaphragm 26 from the valve cage member 24 when the inlet passage pressure 
is sufficiently greater than the control chamber pressure. Accordingly, a 
control channel 102 (FIG. 2) is formed through the valve top member 28 to 
provide fluid communication to the control chamber 94. Since the valve 20 
has been designed so that it can be serviced by removing the top member 28 
without removing the entire valve 20 from the pipeline, it is also desired 
that control loop connections be made to the valve body 22, rather than to 
the top member 28. Accordingly, the channel 102 is sealed with a plug 104 
and a vertical channel 106 intersecting the channel 102 is also formed in 
the top member 28. The channel 106 is aligned with the vertical channel 
108 formed in the valve body 22 when the top member 28 is installed 
thereon. Sealing of these channels is effected by the seal ring 110. A 
horizontal channel 112 is formed in the valve body 22 from its front wall 
114. The channel 112 intersects the channel 108. Accordingly, fluid 
communication to the control chamber 94 may be effected from the front 
wall 114 of the valve body 22. As shown in FIG. 5, a channel 116 is formed 
through the valve body 22 from the front wall 114 to the inlet passage 44, 
and a similar channel 118 is formed through the valve body 22 from the 
front wall 114 to the outlet passage 50. Accordingly, valve control may be 
effected by connections to the front wall 114 of the valve body 22 and the 
valve may be serviced without disturbing any of those control connections. 
In the event the valve 20 is used in an environment where there may be 
debris in the gas line, particularly in a new installation, an inlet 
strainer 120 may be installed in the inlet passage 44. The strainer 120 is 
preferably formed from stainless steel screen material attached to a 
circular metal ring 122. The ring 122 is sized to fit within the opening 
46 of the inlet passage 44 to the valve chamber 22, with a gasket spacer 
124 under the ring 122 securing a tight fit for the ring 122 between the 
valve body 22 and the valve cage member 24. 
FIG. 12 illustrates the valve 20 with an optional heavy duty diaphragm 
assembly 126 used in high pressure applications. As shown, the heavy duty 
diaphragm assembly 126 includes two layers 128, 130 of flexible diaphragm 
material and a fabric reinforcement, a spring cup 132 adjacent the upper 
layer 130, a diaphragm shaft 134 having a deflector 136, and a nut 138 
securing the heavy duty diaphragm assembly 126 together. 
There may be applications where it is desired to set an upper limit on the 
outlet flow as a percentage of the inlet flow. Therefore, modified valve 
cage members are provided wherein the total area of the peripheral 
openings is a percentage of the area of the central opening. Accordingly, 
FIG. 13 depicts a valve cage member 140 arranged to allow up to 75% of 
full flow; FIG. 14 depicts a valve cage member 142 arranged to allow up to 
50% of full flow; and FIG. 15 depicts a valve cage member 144 arranged to 
allow up to 25% of full flow. 
It would be desirable to control the opening and/or closing profile of the 
valve 20 in order to provide greater pressure stability. This is 
accomplished in the design of the valve cage member 24, by the selection 
of the peripheral openings 58 in a progressive manner having no common 
radius from the central opening 56, or in a pattern having peripheral 
opening starting points describing a fixed and repeating number of common 
radii from the central opening 56, so as to provide a more linear, 
logarithmic or tailored opening and closing characteristic. Further, the 
peripheral openings 58 may be selectively non-continuous (bridged) to 
alter the opening and closing characteristics. Illustratively, as shown in 
FIG. 6, the peripheral openings 58 are divided into two groups, with the 
number of peripheral openings in the first group being less than the 
number of peripheral openings in the second group. The peripheral openings 
in the first group, illustratively six in number, are all closer to the 
central opening 56 than are the peripheral openings in the second group, 
illustratively forty eight in number. Thus, as the diaphragm 26 lifts off 
the valve cage member 24, the relatively few peripheral openings in the 
first group are initially exposed, so that the flow through the valve 20 
increases gradually. If, on the other hand, it is desired to effect a 
gradual flow decrease as the diaphragm 26 reseats on the valve cage member 
24, the fewer peripheral openings in the first group would be farther from 
the central opening 56 than would be the peripheral openings in the second 
group. Thus, by arranging the peripheral openings 58 of the valve cage 
member 24 at selected relative distances from the central opening 56, a 
desired opening and/or closing profile can be attained. 
The valve 20 is what is known as a pilot unloading type regulator which 
responds to differential pressure between the control chamber 94 and the 
inlet passage 44. A manifold (not shown) is mounted to the front wall 114 
of the valve body 22. The manifold provides connections to the channels 
112, 116, 118 (FIG. 5) and also provides a connection, which may include a 
variable restrictor, between the channels 116 and 112. When the valve 20 
is configured as a single stage pressure reducer, a pilot valve is coupled 
between the channels 112 and 118 and has its sensing port connected 
downstream of the valve 20. When the downstream pressure decreases, the 
effective opening of the pilot valve is increased. This exhausts gas from 
the control chamber 94 to lower its pressure and allows the diaphragm 26 
to lift from the valve cage member 24 against the force of the spring 30, 
permitting gas to flow through the valve. FIG. 3 illustrates the full flow 
configuration of the valve 20, wherein the diaphragm 26 is against the 
surface 96 of the control chamber 94. Since the surface 96 is the inverse 
of the surface 60 of the valve cage member 24, there is no stretching of 
the diaphragm as it moves symmetrically without elongation from its zero 
flow configuration (FIG. 2) to its full flow configuration (FIG. 3). The 
conical projection 76 of the diaphragm 26 assists in directing the gas 
flow from the central opening 56 of the valve cage member 24 to the 
peripheral openings 58. 
When the downstream pressure increases, the pilot closes and the pressure 
in the control chamber 94 approaches the pressure in the inlet passage 44. 
Accordingly, as the differential pressure across the diaphragm 26 
decreases, the spring 30 moves the diaphragm 26 downwardly to provide a 
positive lockup of the valve 20 in the closed position. 
The valve 20 may be utilized in many different industry-standard 
applications in addition to the single stage pressure reduction described 
above. Thus, the valve 20 may be utilized in a two stage pressure 
reduction application; in a pressure reduction with monitor application; 
as a two stage regulator with monitor override; as a pressure relief 
valve; for on/off control; for underpressure shut off; and for pressure 
regulation with an instrument controller. Various other applications are 
possible. 
As disclosed, the valve 20 may be readily serviced without removing it from 
a pipeline in which it is installed. Thus, by unscrewing the bolts 88, the 
valve top member 28 may be removed without disturbing any of the control 
connections, which are effected through the valve body. After the valve 
top member 28 is removed, the spring 30, the diaphragm 26, the valve cage 
member 24, and the strainer 120 are all accessible for maintenance 
purposes. 
Accordingly, there has been disclosed an improved diaphragm valve for 
regulating gas flow. While several illustrative embodiments of the present 
invention have been disclosed herein, it will be apparent to one of skill 
in the art that various modifications to the disclosed embodiments are 
possible and it is intended that this invention be limited only by the 
scope of the appended claims.