rendered essentially non-existent when using the spray- may be as simple as removing plate 10 from chassis 60, and cooling plate 10 described herein. Plate 10 may be placed typically would not involve disconnecting and virtually as close to a surface of an electronic module as the re-positioning numerous fluid lines. Likewise, the system heights of components (not shown) attached to the module design provides for unobstructed access to individual sprayallow, resulting in compact module packaging because spac- 5 cooled electronic modules, further facilitating inspection ing within chassis 60 may be determined primarily by and repair of the modules.
component height, rather than by air volume requirements. it will be understood that while the embodiments
And unlike air cooling, which is most effective when heat is described show electronic modules being cooled during
spread over a large area, for example, over a large heat sink, normal operation, the present invention is not limited to
spray cooling encourages heat concentration, another factor 10 cooling during ordinary operation of the electronic modules,
contributing to reduced package volume and weight but may be adapted to, for example, testing and evaluation
Referring again to FIG. 5, one example of a closed-loop of the electronic modules or the electronic circuit devices
fluid flow for chassis 60 is illustrated. A fluid supply tube 52 included in the modules.
may be attached to fluid inlet port 23, to provide a flow of It will be further understood that wherever sealing and/or
coolant fluid to conduits formed by fluid distributing con- 15 fastening may be required, numerous methods and materials
duits 28 within plate 10. Alternatively, a fluid supply reser- may be used. For example, fasteners such as screws, com
voir (not shown) may be attached and sealed to a perimeter pliant gaskets, ultrasonic welding, brazing, soldering or
of exterior side 63 of top wall 62 to provide coolant fluid to swaging may be utilized.
plate 10. As a further alternative, a fluid backplane (not It will also be apparent that other and further forms of the
shown)'may be coupled to chassis 60 to supply coolant to 20 invention be devised without departing from the spirit
plate 10. and scope 0f the appended claims and their equivalents, and
A fluid discharge reservoir 48 is attached and sealed to it will be understood that this invention is not to be limited
exterior side 67 of bottom wall 66. Fluid discharge reservoir in any manner to the specific embodiments described above,
48 collects and drains fluid removed from chassis 60. Fluid but will only be governed by the following claims and their
preferably exits chassis 60 via openings (not shown) in 25 equivalents,
bottom wall 66, aided by gravity. Of course, it may be We claim:
desirable to further seal chassis 60, to reduce leakage of 1. An apparatus for spray-cooling an electronic module,
coolant fluid. the apparatus comprising:
A fluid pump 50, which is coupled to fluid supply tube 52, a plate having a first layer and a second layer opposed to
provides a fluid flow. A condenser 53, connected to pump 50 the first layer, the plate sized to be slidably mounted in
by tube 54 and to fluid discharge reservoir 48 by tube 56, a housing;
receives fluid from fluid discharge reservoir Condenser 53 a first fluid distributing conduit disposed in the second
rejects heat from the fluid, returning it to primarily a liquid layer;
phase. Fan 58 may be used to extend the cooling capacity of a second fluid distributing conduit disposed in the second
condenser 53. Cooled fluid is supplied from condenser 53 to layer;
fluid pump 50 Thus, a closed-loop flow of coolant fluid is a &st nozrie housi hayin a ^ er£ur ^ &st
formed. It will be appreciated that at any given pomt m the nozzle housi & d ^ ^ &st fluid distributing
system the coolant fluid may be a vapor, a liquid or a vapor conduit- and
and liquid mixture. ^ a second nozzle housing having a second aperture, the
It is contemplated that any conventional means for pro- Second nozzle housing disposed in the second fluid
viding flow of a coolant may be used in conjunction with the distributing conduit
described embodiments of the present invention. It is further 2 ^ apparatus according to claim 1, further comprising:
contemplated that more than one chassis 60 may be con- a fluM Met ^ d m ^ ^
nected to a smgle source of coolant, and that one or more 45 3 ^ ^us accordin to ^ % wherein me fluid
sources of coolant may be connected to a smgle chassis for ^ Ues a fluM tQ ±e ^ and ...
redundancy purposes, for example. 4 ^ ^stas according to claim 3, wherein the plate
Sizes of fluid pump 50, condenser 53 and fan 58 should is disposed between a first circuit board and a second circuit
be selected based on heat removal and flow-rate require- board.
ments. For example, a typical closed loop fluid flow is 500 50 5. jhe apparatus according to claim 4, wherein the plate
to 1000 milliUters per minute for 500 to 1000 Watts of heat is disposed in a Versa Module Europe (VME) cage,
dissipation. Pump and condenser assemblies in various sizes 6 The apparatus according to claim 4, wherein a first
are available from Isothermal Systems Research, Inc., and nozzle is disposed in the first nozzle housing,
acceptable tubing and fittings may be obtained from Cole- 7. apparatus according to claim 6, wherein the first
Parmer in Vernon Hills, HI. 55 n02zle comprises stainless steel.
The closed-loop fluid flow system described herein has 8. The apparatus according to claim 6, wherein the first
many advantages. For example, it is easily retrofitted to nozzle atomizes the fluid and discharges the atomized fluid
existing rack-type housings. And the system does not require through the first aperture.
managing a multitude of fluid lines or positioning individual 9. The apparatus according to claim 8, wherein the
spray nozzles. Consequently, despite the increase in heat 60 atomized fluid is discharged at a substantially perpendicular
density as circuits are further integrated and physical space angle to the first layer and onto the first circuit board,
on and between electronic modules on printed circuit boards 10. The apparatus according to claim 3, wherein the fluid
is reduced, the fluid delivery and discharge system associ- comprises a dielectric fluid.
ated with the apparatus described herein should not increase 11. The apparatus according to claim 1, wherein the
in complexity. 65 electronic module is selected from the group consisting
The system has also been designed for convenient ser- essentially of: a passive component, a multi-chip module,
viceability. For example, repairing the spray cooling system and an electronic hybrid assembly.