System for attaching a tubular device to a planar device

A fluid connector system for connecting a tubular device such as a conduit having a fluid-bearing capability to a channel port having a fluid-bearing capability in a planar surface, thereby providing a substantially leak-free fluid communication between the conduit and the channel port. The conduit bore communicates with a conduit outlet located in a surface region on the outlet end of the conduit. Located within the outlet end surface region is a weld projection. The channel port is located in a receiver portion of a planar surface and communicates with a channel . A port surface region on the exterior of the planar surface encompasses the channel port. The outlet end surface region and the port surface region are complementary in that they may be superimposed so as to co-locate the conduit outlet and the channel port. The leading edge of the conduit outlet is oriented to contact the port surface region so as to define a line of contact. The weld projection and the material that underlies the line of contact are both formed of electrically resistive material suited to melting and subsequent fusion via resistive heating due to a brief application of an electric current. Accordingly, upon application of a current pulse that is sufficient to cause resistive heating at the weld projection, the weld projection and the material that underlies the line of contact are heated and fused. Upon cooling, the outlet end and the port surface region joined such that a hermetic seal is imposed about the juncture of the superimposed conduit outlet and channel port. A preferred embodiment of the fluid connector system is effective for connecting a conduit to a planar surface in a planar manifold assembly.

FIELD OF THE INVENTION 
The present invention relates to methods and apparatus for effecting 
fluid-tight connection of a tubular device to a planar surface in a planar 
device, and more particularly with a fluid connector system for use in 
connecting apparatus such as tubing to a port in planar manifold assembly 
operable in an analytical instrument. 
BACKGROUND OF THE INVENTION 
Instruments which rely upon regulated fluid flow are commonly employed in a 
wide variety of applications, such as sample purification, chemical 
analysis, clinical assay, and industrial processing. For many instruments, 
an extensive and complex array of tubular devices in the form of tubing, 
fittings, connectors, and the like are employed to provide the many flow 
paths that are necessary for optimum operation, and to effect the 
attachment of other devices such as sensors, valves, and the like. 
Very often, such instruments devices require a complex arrangement of 
devices in a flow system having multiple flow paths. Generally, efficient 
operation of a flow system requires a combination of flow-through 
components, such as valves, sensors, columns, and connective tubing, with 
terminal components, such as needles, pumps, and drains. Different flow 
paths are frequently required to, for example, isolate a component from 
the flow system, include a component into the flow system, or rearrange 
the order of the components in the flow system. Further, there is the need 
to sense certain characteristics of the fluid flow at differing points in 
the flow paths. Examples of such sensed characteristics include the 
pressure, flow rate, and temperature of the fluid. Other characteristics 
related to the particular fluid flow include the presence or absence of a 
fluid component, such as an analyte or contaminant. Such needs are 
typically addressed by the use of fluid connectors for attachment of 
differing devices. Combinations of fluid connectors are sometimes 
necessary to provide flow paths among the flow-through components and 
terminal components employed in a flow system. 
There exists the practical problem, therefore, of connecting an array of 
tubular devices that are required for the multitude of flow path 
combinations in a modern instrument. Another practical problem remains in 
connecting quite a large number of devices in a multitude of flow path 
combinations in a confined spaced within an instrument. The complexity of 
such systems also introduces reliability concerns. Because the instruments 
having these flow systems are sometimes mass-produced for automated or 
unattended operation, the cost and reliability of the fluid connection are 
features critical to successful operation of the instrument. 
Another problem involves the proper orientation of all of the tubing, 
valves, sensors, and the like so as to allow the designer to achieve the 
desired combinations of flow paths, yet also provide an assembly that is 
compact, easily-manufactured, inexpensive, and reliable. The provision of 
fluid-tight connections in a complex fluid-handling assembly has become 
exceedingly problematic as the assembly is reduced in size. 
In response to these problems, U.S. Pat. No. 5,567,868, issued to Craig et 
al., disclosed an instrument, preferably in the form of a chromatograph, 
that includes a computer, a pneumatic controller responsive to the 
computer, and planar manifold assembly. The planar manifold assembly 
includes one or more fluid-handling functional devices attached to a 
planar manifold. Multiple fluid-handling functional devices may then be 
coordinated and assembled so as to connect to pneumatic channels that are 
integrated in the planar manifold, and thus many of the fluid flow paths 
are integral to the planar manifold, which is itself quite compact and 
amenable to construction in a variety of shapes and configurations. The 
advantages of the planar manifold assembly include the reduction of 
external connections between fluid-handling functional devices (such as 
fittings, valves, sensors, and the like) by use of a single planar 
manifold for the provision of a plurality of flow paths. The 
fluid-handling functional devices that connect to the planar manifold are 
constructed to be surface-mounted to offer reliable, fluid-tight 
connection without the complexity and difficulty of previously-known 
pneumatic connections. 
Nonetheless, there still remains a difficulty in effecting such simple, 
reliable, and inexpensive fluid connections between a tubular device and a 
port situated in a planar surface on a planar device. Such planar surfaces 
may be found on a machined part designed for use with the planar manifold 
assembly, such as a microminiature valve, or, in particular, on the 
above-described planar manifold. Conventional fluid connectors have 
several significant disadvantages that make them unsuitable for this task. 
Firstly, they require some type of fitting to be machined, brazed, or 
otherwise attached to the port, thus requiring a substantial fabrication 
cost and effort; secondly, they typically exhibit a dead space 
communicating with the ends of the fluid channels being coupled. A portion 
of the fluid emerging from the end of one channel quickly finds its way 
into the dead space but a relatively long time is required for it to enter 
the other channel. For example, in a tube connected by conventional 
compression fitting connector to a receiving fitting on a detector in a 
chromatograph, the concentration of a sample fluid emerging from one end 
of the tube must increase rapidly to a maximum value and then rapidly 
decay to zero to be detected as a chromatographic peak. When this high 
concentration enters the unswept dead space, it only leaves by diffusion 
which, as it is slow, causes the concentration peak to decay slowly . This 
undesirable phenomenon is known as tailing. As those skilled in the art 
are aware, such a phenomenon can make it difficult to detect separate 
components of the sample. Another significant disadvantage of conventional 
fluid connectors is that the fluid flowing through the fluid connector can 
be degraded by contact with large areas of less-than-inert surfaces of the 
device. Still another significant disadvantage of conventional fluid 
connectors is that planar fluid handling devices, such as the planar 
manifold assembly described hereinabove, are becoming even smaller and are 
designed to be assembled to form a compact, densely-populated arrangement 
of parts. Conventional fluid connectors, in contrast, remain undesirably 
large and bulky. 
There is accordingly a need in many applications for a fluid connector 
system for use in effecting a fluid connection between a tubular device 
and a port on a planar surface in a planar device, wherein such a system 
would offer such attributes as: miniaturization, reliability, simplicity, 
robustness, ease in assembly and maintenance, and low cost. 
SUMMARY OF THE INVENTION 
The present invention provides a fluid connector system for connecting a 
tubular device, preferably provided in the form of a conduit having a 
fluid-bearing capability, to a port having a fluid-bearing capability 
located within a planar surface on a planar device, thereby providing a 
system for effecting a substantially leak-free fluid communication between 
the conduit and the tubular device. 
A preferred method for coupling a tubular device to a channel port situated 
in the planar surface of planar device includes: a) providing the tubular 
device in the form of a conduit having an conduit outlet and a conduit 
outlet surface region that includes a weld projection; b) mounting the 
conduit outlet surface region onto a channel port surface region to engage 
the leading edge of the weld projection against the channel port surface 
region and to superimpose a conduit outlet and the channel port; c) urging 
the planar device and the conduit together to cause a line contact of the 
channel port surface region by the leading edge of the weld projection; 
and d) subjecting the conduit outlet surface region and the channel port 
surface region to a current flow therebetween sufficient to cause 
localized, intense heating at the leading edge of the weld projection and 
at the line of contact. Preferably, the weld projection is provided in an 
annular or similar closed geometric form when viewed along the central 
axis of the conduit, such that the desired configuration of the line 
contact will provide a complete seal about the conduit outlet and the 
channel port. 
A first preferred embodiment of a fluid connector system may accordingly be 
constructed according to the present invention for coupling a tubular 
device to a channel port situated in the planar surface of planar device. 
The bore of the conduit communicates with a conduit outlet located at an 
outlet end of the conduit. Located at the outermost portion of the outlet 
end of the conduit, and encircling the conduit outlet, is a weld 
projection. Preferably, the outlet end of the conduit is flared such that 
an interior bore wall terminates at the weld projection. The channel is 
located in a receiving portion of a planar device and communicates with a 
channel port. A channel port surface region on the exterior of the planar 
assembly encompasses the channel port. The conduit outlet end and the 
channel port surface region are complementary in that they may be 
superimposed so as to co-locate the conduit outlet and the channel port. 
The leading edge of the weld projection is preferably shaped for circular 
line contact with the channel port surface region as the conduit outlet 
surface region is urged against the channel port surface region by a 
biasing force. The leading edge of the weld projection contacts the 
channel port surface region on the planar manifold in a fashion that 
defines a line of contact. The weld projection and the material that 
underlies the line of contact are both formed of electrically resistive 
material suited to melting and subsequent fusion via resistive heating due 
to a brief application of an electric current. Accordingly, upon 
application of a current pulse that flows between the weld projection and 
the channel port surface region, the current density of the pulse is 
concentrated at the line of contact and is sufficient to cause resistive 
heating of the weld projection and the material that underlies the line of 
contact. The weld projection and the material that underlies the line of 
contact are melted, thereby becoming fused together. Upon cooling, the 
channel port surface region and the outlet end of the conduit are found to 
be merged, and the weld projection and the line of contact are fused and 
thus no longer distinguishable, thus attaching the outlet end of the 
conduit to the channel port surface region such that a hermetic seal is 
imposed fabricated the juncture of the interior bore wall and channel 
port. 
In a second preferred embodiment, the outlet end of the conduit need not be 
flared, and preferably forms a sharp, cylindrical peripheral edge. A first 
weld projection is located about the peripheral edge of the conduit 
outlet. The channel port is fabricated to include a second weld projection 
located at the uppermost peripheral edge of the channel port . This second 
weld projection is sized to receive an intermediary conical fitting that 
is placed between the first and second weld projections. That is, the 
interior side wall of the conical fitting is angled and sized so as to 
abut the sharp edge of the first weld projection. The exterior side wall 
of the conical fitting is similarly angled and sized so as to abut the 
sharp edge of the second weld projection. The conduit outlet surface 
region and the channel port surface regions are then superimposed so as to 
co-locate the conduit outlet, the conical fitting, and the channel port. 
The conical shape of the conical fitting causes the conical fitting to be 
self-aligned between the first and second weld projections to aid such 
co-location. 
The leading edges of the first and second weld projections are respectively 
urged against the interior and exterior side walls of the conical fitting 
by a biasing force. The leading edge of each weld projection contacts the 
conical fitting in an opposing fashion that defines respective first and 
second circular lines of contact. Each weld projection and the material in 
the conical fitting that underlies each line of contact are formed of 
electrically resistive material suited to melting and subsequent fusion 
via resistive heating due to a brief application of an electric current. 
Accordingly, upon application of a current pulse that flows between the 
weld projections and the conical fitting, the current density of the pulse 
is concentrated at the first and second lines of contact and is sufficient 
to cause resistive heating of the first and second weld projections and of 
the material that underlies the lines of contact. The weld projections and 
the material that underlies the lines of contact are melted, thereby 
becoming fused together. Upon cooling, the first and second weld 
projections are fused to the conical fitting and thus are generally 
indistinguishable, thus rigidly joining the outlet end of the conduit, the 
conical fitting, and the channel port surface region such that a hermetic 
seal is imposed at the interfaces of the outlet end of the conduit, the 
conical fitting, and the channel port surface region. The conical fitting 
includes a central aperture so as to allow unimpeded fluid communication 
between the conduit bore and the channel port. 
In a third preferred embodiment, the outlet end of the conduit need not be 
flared, and preferably forms a sharp, cylindrical peripheral edge. A first 
weld projection is located about the peripheral edge of the conduit 
outlet. The bore of the conduit communicates with a conduit outlet located 
at the outlet end of the conduit. The channel is located in a receiving 
portion of a planar device and communicates with a channel port. A channel 
port surface region on the exterior of the planar surface encompasses the 
channel port. A portion of the channel port surface region includes a 
conical recess which defines, at its bottom, the channel port. The outlet 
end of the conduit and the channel port surface regions are complementary 
in that they may be superimposed so as to co-locate the conduit outlet and 
the channel port. The leading edge of the weld projection is adapted for 
contact with the interior wall of the conical recess as the outlet end of 
the conduit is urged against the conical recess by a biasing force. The 
leading edge of the weld projection contacts the interior wall of the 
conical recess in a fashion that defines a circular line of contact. The 
weld projection, and the material in the interior wall of the conical 
recess that underlies the line of contact, are both formed of electrically 
resistive material suited to melting and subsequent fusion via resistive 
heating due to a brief application of an electric current. Accordingly, 
upon application of a current pulse that flows between the weld projection 
and the interior wall of the conical recess, the current density of the 
pulse is concentrated at the line of contact and is sufficient to cause 
resistive heating of the weld projection and the material that underlies 
the line of contact. The weld projection and the material that underlies 
the line of contact are melted, thereby becoming fused together. Upon 
cooling, the outlet end of the conduit and the interior wall of the 
conical recess are found to be fused, and the weld projection and the line 
of contact are merged and thus no longer distinguishable, thus joining the 
outlet end of the conduit and the channel port surface region such that a 
hermetic seal is imposed at the juncture of the superimposed conduit 
outlet and channel port. 
Preferred embodiments of a fluid connector system constructed according to 
the present invention may be employed to attach a tubular fitting to a 
planar surface in a planar chromatographic assembly constructed for use in 
an analytical instrument. The planar chromatographic assembly includes a 
planar manifold, a heater assembly for establishing a 
temperature-controlled zone, an injector section, a separation column 
having inlet and outlet ends attached to selected internal fluid-bearing 
conduits in the pneumatic manifold and which is located within the 
temperature-controlled zone, and one or more fluid-handling functional 
devices attached to the pneumatic manifold. Channel ports are provided to 
offer fluid communication with respective etched channels in the planar 
manifold. One or more of the fluid-handling functional devices are 
connected to one or more ports on the planar manifold by way of a fluid 
connector system as described herein to thereby establish fluid 
communication with one or more respective channels. 
The preferred embodiments of the fluid connector system are amenable to 
effect fluid coupling between a planar manifold and tubular device found 
on a variety of fluid-handling functional devices, including: a) passive 
devices such as a fluid coupler or a vent for coupling a fluid stream to 
or from a selected fluid-bearing conduit; b) active devices such as a 
valve, a fluid regulator, or a fluid flow input device (connectable to a 
fluid source) operable in response to a control signal from the control 
system for controlling fluid flow in one or more selected etched channels 
in the planar manifold, or c) signal generating devices such as a sensor 
or detector operable so as to provide sense or detection signal indicative 
of a characteristic of the fluid flow in an etched channel or in the 
separation column. Other preferred tubular devices include narrow bore 
metal tubing, metal capillary separation columns, and the like. 
Fluid connections provided by the preferred embodiments are robust (i.e., 
the hermetic seal withstands operation in an adverse environment, e.g., an 
environment subject to rapid temperature changes or vibration), 
substantially free of dead volume, and offer excellent reliability and a 
long life. Such fluid connections allow an instrument such as a 
chromatograph to be provided in a compact assembly, thus enabling its use 
as a portable unit, or for easy attachment in a confined space with 
respect to a flow system to be analyzed, thus enabling an analysis of a 
chemical process in an "on-line", "at-line", or similarly oriented type of 
chemical process analysis. 
Fluid connections that would previously be impossible or impractical to 
establish between a tubular device and a planar device may now be 
provided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention will find use in a variety of applications that 
benefit from effective connection of one or more fluid streams in 
respective fluid-bearing conduit to a planar device. 
The apparatus and methods of the present invention are especially 
applicable to provide fluid connections between a port on a planar surface 
and a tubular device in a fluid system that effects the initiation, 
distribution, redirection, termination, control, sensing, and other types 
of fluid handling functions with respect to one or more of fluid streams 
(and such functions thus collectively defined herein as fluid handling 
functions); Liquids and gases are the preferred fluids according to the 
practice of the present invention, and the following description of the 
invention will describe the construction and operation of certain portions 
of an analytical instrument, and in particular of the fluid-tight 
connections of a gaseous stream in a gas chromatographic analytical system 
(hereinafter, a chromatograph). However, for the purposes of the following 
description, the term "fluid" will be considered to refer to all liquids, 
gases, mixtures of gases and liquids, supercritical fluids, and fluidized 
materials or mixtures, e.g., slurries, dispersions, etc.; in short, the 
term "fluid" refers to all types of fluids. 
In the Figures and the description to follow, like nomenclature and numeric 
identifiers will refer to like components; signal lines are drawn 
schematically by single solid lines; fluid flow lines or channels are 
drawn schematically as double solid lines. 
An analytical instrument is shown in FIG. 1 and is generally designated as 
chromatograph 110 having a planar manifold assembly 120 and a control 
section 130. The planar manifold assembly 120 is provided in a compact 
configuration such that, in comparison to a conventional gas 
chromatograph, the planar manifold assembly 120 occupies less volume, has 
a smaller footprint, is amenable to configuration as a portable unit, is 
less complex and costly to manufacture, and consumes less operating power. 
In order to perform a chromatographic separation of a given sample 
compound, a sample is injected into the planar manifold assembly 120 with 
a pressurized carrier gas by means of a sample inlet 111. The carrier gas 
supplied to inlet 111 is provided from a source 124A through one or more 
fluid connectors 112A into a planar manifold 113, which incorporates 
internal channels capable of bearing fluid flow, each of which serve in 
part to control or redirect a plurality of gas flows. The detector gases 
are provided from respective sources (one such source 112B is shown) 
through respective fluid connectors 112B to the planar manifold 113. A 
separation column (not shown) may be attached to a portion of the planar 
manifold 113 at its inlet and outlet ends to selected channels 125 in the 
planar manifold 113 by respective fluid connectors 112C, 112D. The carrier 
gas/sample combination passing through column is exposed to a temperature 
profile by known means. During this profile of changing temperatures, the 
sample will separate into its components primarily due to differences in 
the interaction of each component with the column 114 at a given 
temperature. As the separated components exit the column, they are 
detected by a detector 124. 
In a first feature of the present invention, at least some of the 
fluid-handling functional devices in the planar manifold assembly 120 are 
contemplated as being connected to the planar manifold 113 by way of 
preferred embodiments of a fluid connector system described herein. The 
contemplated fluid-handling functional devices include passive devices 
such as the aforementioned tubing, inlet 111, fluid connectors 112A, 112B, 
112C, 112D; active devices such as valves 115, regulators (not shown in 
FIG. 1), and the like; and signal generating devices such as sensors 108, 
detector 124, and so on. The active devices and the signal generating 
devices are contemplated as being operated under control signals generated 
by the control section 130 on data and control lines 123A, 123B, and 128 
connected to computer 122 and pneumatic controller 126. Accordingly, the 
computer 122, pneumatic controller 126, and planar manifold 113 may be 
operated to effect a variety of fluid handling functions. The planar 
manifold assembly 110 preferably includes one or more electronic signal 
connectors 109 and associated cabling (shown in simplified form as line 
123B for clarity) for control, data, and power signals as may be needed. 
It is contemplated that for some applications an optional interface in the 
form of an electronic control panel 150 having a keypad 158 and a display 
160 may be included. 
Turning now to FIGS. 2-5, a preferred embodiment of a planar manifold 210 
contemplated by the present invention includes a front plate 210A having 
front surface 210C and a back plate 210B having back surface 210D; these 
plates are sized and constructed to be superimposed and bonded together 
during the manufacturing process to form the planar manifold 210. 
Preferably, the front plate 210A and back plate 210B are machined from 
nickel-plated stainless steel and etched to provide an arrangement of 
etched channels 210E each capable of sustaining fluid flow. That is, the 
etched channels 210E form a predetermined array of internal channels when 
the front plate 210A and back plate 210B are bonded together to form the 
planar manifold 210. 
In contrast to the conventional approach, wherein the task of forming 
complex interconnected flow paths usually involves the use of many 
discrete pieces of tubing and fittings through which the pieces of tubing 
can be attached, the planar manifold 210 replaces conventional manifolds 
at a fraction of the cost and with minimal labor. The planar manifold 210 
is robust, rigid, shock proof, and unaffected by operation in a high 
temperature environment. Hence, the planar manifold 210 is intended as a 
primary structural support member of the embodiment 200, in addition to 
serving as a flow manifold for receiving fluid connections to fluid 
handling functional devices, and for managing a complex arrangement of 
fluid flows. Further details on the design and manufacturing of a planar 
manifold having etched channels therein may be found in commonly-assigned 
U.S. Pat. No. 5,567,868, issued to Craig et. al., the disclosure of which 
is included herein by reference. 
As will now be described, certain ones of the etched channels such as 
channels 203A, 210E in one or both of the front and back plates 210A, 210B 
are connected, via one or more of the preferred embodiments of the present 
invention, to a selected fluid-handling functional device. 
As illustrated in FIGS. 2A-2B, planar manifold 210 includes the front 
surface 210C having therein a variety of ports 203P and etched channels 
210. Certain ones of the etched channels 210E may be directed to 
respective ones of the channel port surface regions 203S, each having a 
port 203P, being suitable for effecting fluid communication with a 
complementary conduit outlet in a selected one of three preferred 
embodiments of a fluid connector system 220. In particular, the etched 
channels 210E extend to the portion of the planar manifold 210 (preferably 
in the immediate vicinity of the port 203P) where an interface surface 
210F is located. 
As illustrated in FIGS. 3A-3B, a first preferred embodiment of a fluid 
connector system includes a flared conduit 221 for establishing fluid 
communication between a channel 210E in the planar manifold 210 and a bore 
221R in the conduit 221. The fluid connector system is designed to provide 
fluid communication between the internal bore 221R of the conduit 221 to 
the port 203P and hence to the etched channel 210E. The conduit 221 is 
constructed to include a flared outlet end 221P and generally cylindrical, 
parallel interior and exterior walls 222, 224. Impressing the conduit 221 
onto the manifold 210 superimposes the leading edge of a flared interface 
surface 221F onto the interface surface 210F on the planar manifold 210. 
The bore 221R is thus superimposed over the port 203P. It is important to 
insure integrity and freedom from leakage in the fluid communication 
between the bore 221R and interface surfaces 222F and 210F. Accordingly, 
the flared outlet end 221P of the conduit 221 is sharply cut, thus 
allowing the leading-edge of the flared interface surface 221F to function 
as a circular weld projection 221W that encompasses the terminal end of 
the bore 222R. The conduit 221 is aligned coaxially with port 203P while 
being oriented perpendicularly to the interface surface 210F. By biasing 
the weld projection 221W against the interface surface 210F and upon 
application (by suitable electrode means not shown) of an electrical 
current pulse between the conduit 221 and the interface 210F, the line of 
contact between the weld projection 222W and the interface surface 210F is 
subject to a brief period of extremely high current density, whereupon the 
interface surface 221F is fused to the interface surface 210F. The conduit 
221 is thereafter found to be rigidly fixed to the planar manifold 210 in 
an upright position, as illustrated in FIG. 4B, and the interface surfaces 
210F, 221F are welded together. Accordingly, the bore 221R is unified in a 
fluid-tight connection with the etched channel 210E. 
As illustrated in FIGS. 4A-4B, a second preferred embodiment of a fluid 
connector system includes a straight conduit 321 for establishing fluid 
communication between the channel 210E in the planar manifold 210 and a 
bore 321R in the conduit 321. Bore 321R is designed to provide fluid 
communication with the port 203P and hence to the etched channel 210E. The 
conduit 321 includes straight cylindrical parallel interior and exterior 
walls 322, 324. The conduit 321 is aligned coaxially with port 203P while 
being oriented perpendicularly to the surface 210C. The outlet end 321P of 
the conduit 321 is centered and impressed upon an interior surface 323 of 
a conical fitting 321B which in turn is centered and impressed upon an 
interface surface 210F in the manifold 210. The bore 421R is thus 
superimposed over a central opening 326 in the conical fitting 321B, so as 
allow it to communicate with the port 203P when superimposed. It is 
important to insure integrity and freedom from leakage in the fluid 
communication between the bore 321R and channel 210E at the junction of 
interface surface 321F with the interior surface 323, and at the junction 
of exterior surface 321B and the interface surface 210F. Accordingly, the 
outlet end 321P of the conduit 321 is sharply cut, thus allowing the 
interface surface 321F to include, at its peripheral edge, a weld 
projection 321W. The port 203P is also sharply cut in the surface 210C, 
thus affording, at its uppermost periphery, an inner edge that serves as a 
weld projection 203W. By biasing the weld projection 321W against the 
interior surface 323 and the exterior surface 321B against the weld 
projection 203W, and upon application (by suitable electrode means not 
shown) of an electrical current pulse between the conduit 421, conical 
fitting 321B, and the interface surface 210F, the two circular lines of 
contact between the weld projections 321W and 203W and the conical fitting 
321B are subject to a brief period of extremely high current density, 
whereupon the interface surface 321F is fused to the interior surface 323 
and the exterior surface 321B is fused to the interface surface 210F. The 
conduit 421 and conical fitting 321B are thereafter found to be rigidly 
fixed in the positions illustrated in FIG. 4B with respect to the planar 
manifold 210. Accordingly, the bore 321R is unified in fluid communication 
with the etched channel 210E. 
As illustrated in FIGS. 5A-5B, a third preferred embodiment of a fluid 
connector system includes a straight conduit 421 for establishing fluid 
communication between the channel 210E in the planar manifold 210 and a 
bore 421R in the conduit 421. Bore 421R is designed to provide fluid 
communication to the port 203P and hence to the etched channel 210E. The 
conduit 421 includes straight, cylindrical, parallel interior and exterior 
walls 422, 424. Impressing the conduit 421 onto the manifold 210 
superimposes the leading edge of an interface surface 421F onto an 
interface surface 410F especially prepared to include a conical recess in 
the planar manifold 210. The bore 421R is thus superimposed over the port 
203P. It is important to insure integrity and freedom from leakage in the 
fluid communication between the conduit 421 at the junction of interface 
surfaces 421F and 410F. Accordingly, the outlet end 421P of the conduit 
221 is sharply cut, thus allowing the interface surface 221F to include, 
at its outermost peripheral edge, a weld projection 221W. The conduit 421 
is aligned coaxially with port 203P while being oriented perpendicularly 
to the surface 210C. By biasing the weld projection 421W against the 
interface surface 410F and upon application (by suitable electrode means 
not shown) of an electrical current pulse between the conduit 421 and the 
interface surface 410F, the circular line of contact between the weld 
projection 421W and the interface surface 410F is subject to a brief 
period of extremely high current density, whereupon the interface surface 
421F is fused to the interface surface 410F. The conduit 421 is thereafter 
found to be rigidly fixed in an upright position with respect to the 
planar manifold 210, and the interface surfaces 410F, 421F are welded 
together. Accordingly, the bore 421R is unified in fluid communication 
with the etched channel 210E. 
Preferred embodiments of the weld projections 221W, 321W, 421W, 203W are, 
as already described, each provided in the form of a sharply cut circular 
edge. For example, and as illustrated and FIGS. 6 and 7, the weld 
projection 221W is respectively formed by the interior peripheral edge of 
the outlet end of conduit 221; the weld projection 421W is respectively 
formed by the exterior peripheral edge of the outlet end of conduit 421. 
The illustrated embodiments of a fluid connector system are useful in 
establishing a fluid connection between a tubular device and a planar 
surface on a fluid handling functional device, such as a valve, Inlet 
block, and the like, or between a tubular device and a planar surface on a 
planar device, such as a planar manifold assembly, and afford the 
following benefits and advantages. The overall system is compact and uses 
fewer conventional fluid connections, which would otherwise undesirably 
increase the overall volume of the system. Reliable fluid connections 
between fluid-handling functional devices (such as fittings, valves, 
sensors, and the like) may be provided in a plurality of flow paths in the 
illustrated planar manifold. More miniaturized fluid-handling functional 
devices may be connected to the planar surface. 
A large number of fluid-handling functional paths may thus be integrated 
into a planar device having a compact, low-profile form factor in a 
fashion that heretofore would be difficult if not impossible to assemble 
using traditional tubular pipe, ferrules, and manual fittings. Also, 
considerable cost savings and improved reliability are realized by 
reduction of the number of connections necessary to achieve multiple flow 
paths. The fluid connections provided by the invention also reduce the 
complexity of an assembly that includes fluid connections to a planar 
surface on a planar device, which is desirable during the stages of 
manufacturing, assembly, repair, or modification of, e.g., an analytical 
instrument in which the planar device may be situated. 
Another advantage is that a planar device may be constructed to include 
connections to certain conventional fluid-handling devices, such as a 
capillary separation column, that otherwise are difficult to connect to a 
planar surface, thus saving cost and providing for simpler manufacturing. 
While the invention has been described and illustrated with reference to 
specific embodiments, those skilled in the art will recognize that 
modification and variations may be made without departing from the 
principles of the invention as described herein above and set forth in the 
following claims.