Metering valve

A valve body includes a chamber for the flow of fluid between an inlet and an outlet thereto. The chamber includes an upper portion with an opening therethrough and a lower portion including a valve seat between the inlet and outlet. A bonnet is positioned in the chamber upper portion and is connected to the valve body and extends upwardly therefrom. The bonnet includes a passageway, and a stem is positioned in the passageway for longitudinal movement into and out of sealing engagement with the valve seat. An actuator is rotatably positioned in the bonnet passageway above the stem. A micrometer operating handle is nonrotatably connected to the upper end portion of the actuator to facilitate fine adjustment of the stem position to provide incremental adjustments in the flow rate of fluid between the inlet and outlet. The stem upper end is spaced from the actuator lower end in the bonnet passageway, and a coupling assembly rigidly connects the actuator to the stem for conversion of longitudinal rotational movement of the actuator to nonrotational longitudinal movement of the stem. The coupling assembly includes a housing into which both the actuator and stem extend. The housing is retained on the end of the actuator, and a pin connects the housing to the stem. A bushing is positioned between the adjacent ends of the actuator and stem where one surface of the bushing abuts the actuator and an opposite surface abuts the stem. The stem is sealed in a bellows which exerts an upward compressive force upon the stem to maintain the actuator and stem in contact with the bushing so that, as the actuator rotates, the stem moves longitudinally relative to the valve seat.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a metering valve and, more particularly, to a 
valve for providing measurable fine flow control by nonrotational 
longitudinal movement of a valve stem sealed in a bellows and connected by 
a coupling to an actuator that is rotatably mounted for axial movement in 
a bonnet of the valve. 
2. Description of the Prior Art 
Metering bellows valves for precisely controlling the flow of toxic, 
corrosive, or expensive liquids or gases through a piping system are well 
known in the art. U.S. Pat. No. 3,428,291 is an example of a bellows 
metering valve having a nonrotating stem that is incrementally movable to 
assume accurate sealing of a valve member relative to a valve seat. In 
view of the fact that a bellows surrounds part of the stem and is 
connected to the upper end of the stem, the stem must be prevented from 
rotating and exerting torsional loads on the bellows when the actuator is 
threadedly rotated within a bonnet. 
As disclosed in the above-identified patent, rotation of the stem upon 
rotation of the actuator is prevented by guiding the stem at its lower end 
by a washer and at its upper end by a bore in the bonnet where rotation of 
the stem is prevented by interaction of a flat on the washer with a 
corresponding flat on the stem. Fine adjustments of the flow rate through 
the valve are obtained by a differential thread mechanism that includes 
relatively coarse threads on the exterior of the bonnet and finer threads 
on the end of the valve stem with an actuator threadedly engaging with a 
first threaded portion the coarse threads on the bonnet and with a second 
threaded portion the fine threads on the valve stem. As the actuator is 
rotated relative to the bonnet and the stem, the stem advances a net 
amount equal to the difference in the pitch between the bonnet and the 
stem threads to provide accurate setting for the flow through the valve. 
U.S. Pat. Nos. 3,278,156 and 3,428,291 disclose bellows metering valves in 
which the actuator is threadedly retained in the bonnet and includes a 
socket end portion having a conical recess for receiving a dome-shaped end 
portion of the valve stem. The end of the stem is retained in the conical 
recess by a pin extending through the conical recess and engaging a radial 
groove on the end of the stem within the recess. Longitudinal rotational 
advancement of the actuator generates non-rotational longitudinal movement 
of the valve stem as a result of the connection of the valve stem to the 
actuator. 
U.S. Pat. Nos. 3,679,169 and 3,751,053 disclose high pressure needle valves 
in which a valve needle is non-rotatably retained in a valve body. An 
actuating stem is longitudinally rotationally mounted in the valve body 
and includes a socket-like end portion that receives an enlarged spherical 
end portion of the valve needle. A positive contact of the spherical end 
portion is maintained in the socket of the actuating stem so that 
rotational, longitudinal movement of the actuating stem is converted to 
non-rotational movement of the valve needle. U.S. Pat. No. 3,356,335 is 
another example of a metering valve that provides interconnecting means 
between a handle or actuator with the stem whereby rotational movement of 
the handle generates longitudinal movement of the stem without rotation of 
the stem. 
While it has been suggested to provide metering valves with non-rotational 
longitudinally movable valve stems, some of the known mechanisms for 
connecting the rotational actuator to the stem include direct contact of 
the actuator with the stem. This means of connection, while effective to 
prevent rotation of the valve stem, is subject to wear at the point of 
contact of the stem with the actuator. The wear at this point between the 
actuator and the stem is undesirable, particularly in a metering valve 
where precise flow control is required. Consequently, the contacting parts 
must be frequently inspected to insure positive response of the valve stem 
to rotation of the actuator. The other known arrangements which provide 
for interconnecting means between the actuator and the stem in which the 
stem and the actuator do not contact each other require complex machining 
to assure that the desired accuracy of the flow control is maintained. 
Therefore there is need in a metering valve, and particularly in a bellows 
metering valve, for an arrangement that connects the actuator to the valve 
stem in a manner that does not require complex machining and prevents wear 
of the connected parts where solid contact is maintained between the 
connection of the actuator to the valve stem in order to obtain precise, 
repeatable flow settings. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a valve that 
includes a valve body having a chamber therein. The chamber includes an 
upper portion with an opening therethrough and a lower portion having a 
valve seat. Inlet and outlet openings extend through the valve body and 
communicate with the valve seat. A bonnet is positioned in the chamber 
upper portion and is connected to the valve body. The bonnet has a 
passageway therethrough aligned with the chamber. A stem is positioned for 
longitudinal movement in the bonnet passageway. The stem includes a lower 
end portion extending into the chamber lower end portion and is adapted to 
sealingly engage the valve seat. The stem includes an upper end portion 
positioned in the bonnet passageway. An actuator is rotatably supported in 
the bonnet passageway above the stem. The actuator includes an upper end 
portion and a lower end portion. Coupling means is positioned in the 
bonnet passageway for connecting the actuator lower end portion to the 
valve stem upper end portion to convert rotation of the actuator to 
non-rotational longitudinal movement of the valve stem in the bonnet 
passageway to move the valve stem lower end portion into and out of 
engagement with the valve seat. The coupling means includes a housing with 
a bore therethrough. The actuator is positioned in the upper portion of 
the bore and is provided with means for retaining the actuator in the 
housing bore. The valve stem upper end portion is positioned in the lower 
portion of the housing bore in spaced relation with the actuator. The 
coupling means further includes means for rigidly connecting the valve 
stem upper end portion to the housing and a member positioned in the 
housing bore between the actuator and the valve stem upper end portion. 
The member has one surface abutting the actuator and an opposite surface 
abutting the valve stem upper end portion to maintain positive contact 
between the actuator and the valve stem through the member. 
In one embodiment the member includes a bushing having opposed concave or 
arcuate surfaces. The actuator has an arcuately shaped end portion that 
complementary engages the upper surface of the bushing. The valve stem 
upper end portion also has an arcuately shaped end portion for 
complementary engagement with the opposite surface of the bushing. 
A portion of the valve stem is enclosed by a bellows, which is connected at 
an upper end portion to the valve stem below the connection of the valve 
stem to the actuator. The bellows is installed around the valve stem in a 
precompressed state so as to apply an upward biasing force on the valve 
stem and provide positive contact between the valve stem and the actuator. 
This assures that rotation of the actuator is converted to longitudinal 
displacement of the valve stem for precise settings of the valve. 
Another feature of the present invention includes the coupling housing 
having an internal shoulder positioned oppositely of a shoulder on the end 
portion of the actuator adjacent the bushing. The shoulder of the housing 
is maintained in close adjacency to the shoulder of the actuator by a pin 
extending through aligned bores in the valve stem and the housing so as to 
integrally connect the stem to the coupling means. In this manner, the 
coupling means serves as a tension member to exert an upward force upon 
the stem to maintain direct contact with the actuator in the event the 
compressive effect of the bellows is lost. 
Accordingly, the principal object of the present invention is to provide a 
metering valve having a valve stem sealed in a bellows and connected to an 
actuator in a manner to assure positive contact between the actuator and 
the valve stem so that the valve stem is responsive to minute rotation of 
the actuator to precisely control the setting of the valve stem and flow 
through the valve. 
Another object of the present invention is to provide a bellows sealed 
metering valve having an actuator to stem wear resistant connection to 
assure precise non-rotational longitudinal movement of the valve stem in 
response to minute rotation of the actuator. 
A further object of the present invention is to provide in a metering valve 
a bellows for sealing a portion of the valve stem and exerting an upward 
compressive force to maintain the stem in positive contact through a 
coupling assembly to an actuator. 
Another object of the present invention is to provide an actuator to stem 
connection for a metering valve in which positive contact is maintained 
between the actuator and the stem in a manner to reduce wear of the 
interconnecting parts and eliminate complexity of the connection between 
the stem and the actuator. 
These and other objects of the present invention will be more completely 
disclosed and described in the following specification, the accompanying 
drawings and the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the FIGURE, there is illustrated a metering valve generally 
designated by the numeral 10 for precisely controlling the flow of fluid, 
such as a toxic, corrosive, or expensive liquid or gas through a piping 
system. The valve 10 includes a body portion 12 having a pair of conduit 
portions 14 and 16 communicating with ports 18 and 20 in the valve body 
12. The ports 18 and 20 are adaptable to receive suitable compression 
couplings for connection to the conduits of a piping system. 
The valve body 12 includes a chamber 22 having an upper portion 24 with an 
opening 26 therethrough and a lower portion 28 having a valve seat 30 
therein. The conduit portions 14 and 16 include openings 32 and 34 
respectively communicating with the chamber 22 for fluid flow between the 
ports 18 and 20 through the valve seat 30. 
A bonnet 36 is positioned in the chamber upper portion 24 and closes the 
opening 26 in the chamber upper portion 24. The chamber upper portion 24 
forms a counterbore in the valve body 12 and is adapted to receive on a 
shoulder 38 of the valve body 12 a bellows plate 40 and a gasket 42. Both 
the bellows plate 40 and the gasket 42 are supported by the valve body 12 
surrounding the chamber upper portion 24 and include bores therethrough 
having a diameter greater than the diameter of the chamber 22 above the 
valve seat 30. The bonnet 36 has a lower end portion 44 that bears 
downwardly on the bellows plate 40. The lower end portion 44 includes an 
external shoulder 46 positioned above the valve body 12. The valve body 12 
includes an externally threaded portion 48 positioned below the bonnet 
shoulder 46. 
The bonnet 36 also includes an externally threaded portion 35 positioned 
above a union nut 50 and is adapted to receive a jam nut 37. The jam nut 
37 is operable to permit panel mounting of the valve 10. In the 
alternative, the base 39 of the valve body 12 can be provided with tapped 
holes (not shown) to facilitate bottom mounting of the valve 10. 
The union nut 50 includes an internally threaded bore 52 and an internal 
shoulder 54 surrounding a bore 56. The union nut 50 is advanced downwardly 
in surrounding relation with the bonnet 36 to a position where the bore 56 
surrounds the bonnet 36 above the shoulder 46 and the nut internally 
threaded bore 52 engages the valve body externally threaded portion 48. 
The union nut 50 is threadedly advanced downwardly onto the valve body 12 
so that the nut shoulder 54 bears against the bonnet shoulder 46 to urge 
the bonnet lower end portion 44 into bearing engagement with the bellows 
plate 40. Continued tightening of the nut 50 on the valve body 12 
compresses the gasket 42 on the valve body shoulder 38. Thus, compression 
of the gasket 42 provides a fluid tight seal between the bonnet 36 and the 
valve body 12 around the valve chamber opening 26. 
The bonnet 36 has a passageway 58 aligned with the valve body chamber 22. A 
valve stem 60 is positioned in the bonnet passageway 58 and includes a 
needle end portion 62 positioned in the chamber lower end portion 28. In 
the closed position of the valve 10, the needle end portion 62 sealingly 
engages the valve seat to prevent flow of fluid through the valve body 12 
between the ports 18 and 20. In the open position of the valve 10, the 
needle end portion 62 is raised out of sealing engagement with the valve 
seat 30 to a selected position relative to the valve seat 30 corresponding 
to a preselected flow rate through the valve 10. With this arrangement, 
the needle end portion 62 is precisely positioned relative to the valve 
seat 30 to permit fine adjustments of the flow rate through the valve. 
A fluid impervious bellows 70 surrounds a portion of the valve stem 60 in 
the bonnet passageway 58. The bellows 70 is preferably fabricated of 
metallic material, such as stainless steel, and includes an upper end 
portion 72 welded to an integral flange 74 of the stem 60 and a lower end 
portion 76 which extends into the bore of the bellows 70 and is welded to 
the bellows plate 40. With this arrangement, the bellows 70 hermetically 
seals the lower portion of the stem 60 within a primary pressure boundary 
and contains the fluid flowing throgh the valve 10 within the bellows 70 
around the stem 60. Thus, in the event that fluid leaks upwardly through 
the valve seat 30 and around the stem 60 into the valve chamber upper 
portion 24, the fluid is contained in the bellows 70. 
As will be explained later in greater detail, the stem 60 is nonrotatably, 
longitudinally movable in the bonnet passageway 58. As the stem needle end 
portion 62 is raised and lowered relative to the valve seat 30 
corresponding to a preselected flow rate, the bellows 70 is longitudinally 
expandable and retractable to maintain a hermetic seal around the lower 
portion of the stem 60. By preventing rotational movement of the stem 60 
as the needle end portion 62 is raised and lowered, torsional loading of 
the bellows 70 is prevented. Also, as will be explained later in greater 
detail, the bellows 70 is installed in a precompressed state on the stem 
60 to normally exert an upward force such as a compression coil spring, 
upon the valve stem 60. 
The bonnet passageway 58 includes a lower end portion 78 for receiving the 
bellows 70 and an upper end portion 79. The stem 60 is positioned in the 
bellows 70. An upper end portion 80 of the stem 60 extends out of the 
bellows 70. The bonnet passageway upper end portion 79 includes a conical 
recess 82, and an internally threaded bore 84 extends from the recess 82 
upwardly through an upper end portion 86 of the bonnet 36. 
Operation of the valve 10 for a preselected flow rate is controlled by 
rotation of a cup-shaped operating handle 88 that includes a bore 90 for 
receiving an actuator 92. The handle 88 is nonrotatably connected to the 
upper end of the actuator 92 by a set screw 94. The handle 88 includes a 
lower end portion 96 that is received over a sleeve 98 that is positioned 
around and abuts a shoulder 100 of the bonnet upper end portion 86. The 
sleeve 98 is nonrotatably connected to the bonnet upper end portion 86 by 
a set screw 102. The sleeve 98 includes a vernier scale, which is 
preferably graduated in 0.001 inch increments for metering minute flow 
rates through the valve 10. The vernier scale cooperates with the 
appropriate indicia on the handle lower end portion 96 to accurately 
indicate the flow rate through the valve 10. 
The actuator 92 includes a portion 104 having a very fine thread pitch. The 
threaded portion 104 is threadedly received within the threaded bore 84 of 
the bonnet 36. The bonnet 36 also includes a transverse threaded bore 106 
positioned below the threaded bore 84 for receiving a set screw 108 that 
is operable to engage the actuator 92 to prevent rotation of the actuator 
92 and thereby lock the valve stem 60 in a desired position corresponding 
to a preselected flow rate. 
The actuator 92 includes a lower end portion 110 that extends into the 
bonnet passageway 58 and includes an arcuately shaped head 112 having a 
peripheral shoulder 114. The actuator end portion 110 is connected to the 
stem upper end portion 80 by a coupling assembly, generally designated by 
the numeral 116. The coupling assembly 116 is positioned in the bonnet 
passageway 58 and is operable to connect the valve stem 60 to the actuator 
92 in a manner to convert rotation of the actuator 92 to nonrotational, 
longitudinal movement of the valve stem 60. Longitudinal movement of the 
valve stem 60 moves the valve stem needle end portion 62 into and out of 
engagement with the valve seat 30. The coupling assembly 116 also serves 
to prevent the application of torsional loads on the bellows 70 when the 
actuator 92 is threadedly rotated within the bonnet 36. 
The coupling assembly 116 includes a sleeve-like housing 118, a member 128 
and a coupling pin 132. The housing 118 has a bore therethrough that 
includes an enlarged diameter portion 120 separated from a reduced 
diameter portion 122 by an internal shoulder 124 that is positioned 
opposite the shoulder 114 on the actuator head 112. The housing 118 also 
includes a conical shaped upper end portion 126 that is adaptable to be 
received within the conical recess 82 of the bonnet 36 and thereby limit 
the extent of upward movement of the valve stem 60 in tne bonnet 36. 
The valve stem upper end portion 80 extends into the housing enlarged bore 
120 and is maintained in spaced relation with the actuator head 112 by a 
member generally designated by the numeral 128. The stem upper end portion 
80 is connected to the housing 118 by the provision of a coupling pin 130 
that extends through aligned bores in the valve stem upper end portion 80 
and the lower end portion of the housing 118. The coupling pin 130 
maintains the housing 118 and the stem 60 as an integral unit. Thus, the 
coupling assembly 116 is operable as a compression device to maintain 
contact between the actuator 92 and the stem 60 through the member 128. 
The member 128 includes in one embodiment a bushing 132 maintained in 
abutting contact with the actuator head 112 and the stem upper end portion 
80. To accomplish a solid connection between the stem 60 and the actuator 
92 without providing for direct contact of the valve stem upper end 
portion 80 with the actuator head 112, the bushing 132 is provided with 
complementary surfaces which coact with the arcuate surfaces on the stem 
end portion 80 and the actuator head 112. With this arrangement, the 
bellows 70, acting as a compression spring, applies an upward compressive 
force upon the stem 60 to maintain contact between the stem 60 and the 
actuator 92 through the bushing 132. 
The bushing 132 is provided with an upper concave surface 134 that is 
complementary with the convex surface of the actuator head 112. Similarly, 
the bushing 132 is provided with a lower concave surface 136 that is 
complementary with the convex surface on the stem upper end portion 80. 
With this arrangement, the bushing 132 is compressed by the upward 
compressive force exerted by the bellows 70 between the adjacent end 
portions of the actuator 92 and the valve stem 80. 
The connection of the coupling housing 116 at one end to the valve stem 60 
and at the opposite end to the actuator 92 maintains solid contact between 
the actuator 92 and the valve stem 60 through the bushing 132. With the 
housing 118 being pinned to the valve stem 60, the upward compressive 
force exerted by the bellows 70 upon the stem 60 is transmitted to the 
housing 118 to maintain the valve stem 60 in contact with the bushing 132. 
This in turn maintains the bushing 132 in solid contact with the actuator 
head 112. 
The bushing 132 is maintained compressed between the adjacent ends of the 
actuator 92 and the valve stem 60. However, in the event the compressive 
effect of the bellows 70 against the coupling assembly 116 is lost when 
the valve 10 is being opened, the coupling assembly 116 is operable, as a 
tension device, to maintain a rigid connection between the actuator 92 and 
the stem 60 where rotational movement of the actuator 92 is converted to 
nonrotational, longitudinal movement of the valve stem 60. Thus, in the 
event the compressive effect of the bellows 70 is lost when the valve is 
opened, the actuator shoulder 114 will engage the shoulder 124 of the 
housing 118 to lift the housing 118 upwardly and carry with it the valve 
stem 60 which is maintained coupled to the housing 118 by the pin 130. 
With the metering valve 10 of the present invention, precise repeatable 
settings in minute flow rates through the valve 10 are obtained. A 
positive connection between the actuator 92 and the valve stem 60 is 
maintained during the operation of the valve 10. The connection provided 
by the coupling assembly 116 eliminates the problems of wear encountered 
when the actuator 92 and stem 60 are in direct contact. This connection 
avoids the problems heretobefore encountered with complex machining and 
provides a coupling that maintains the actuator 92 and stem 60 in spaced 
relation but connected as an integral unit in a manner to provide accurate 
movement of the valve needle end portion 62 in response to incremental 
rotational movement of the operating handle 88. 
According to the provisions of the patent statutes, we have explained the 
principle, preferred construction and mode of operation of our invention 
and have illustrated and described what we now consider to represent its 
best embodiments. However, it should be understood that, within the scope 
of the appended claims, the invention may be practiced otherwise than as 
specifically illustrated and described.