Sheet-member containing a plurality of elongated enclosed electrodeposited channels and method

Abstract

A sheet member and a method for constructing the sheet member. The sheet member includes a plurality of elongated, enclosed channels formed by electrodeposition.

Description

patent application Ser. No. 904,358 filed Sep. 1986 and now abandoned Pat. No. 4,875,259 entitled "Intermeshable Fasteners", which is incorporated herein by reference. In this embodiment, projections 42 each include at least one side inclined relative to the base layer 40 at an angle sufficient to form a taper such that said projection may mesh with at least one corresponding projection when brought into contact with said corresponding projection and adhere thereto at least partially because of the frictional characteristics of the contacting sides. Further, the projection 42 of the sheet member 38 may be utilized to radiate or convey heat from fluids circulated through the channels, as hereinafter described.

However, in many applications, it is desirable to construct additional channels on the sheet member 38. In such a case, the sheet member is utilized as a first sheet portion 38a constituting a mandrel for generating a complementary second sheet portion 38b integrally joined to the first sheet portion, as shown in FIGS. 7-9. The method of this invention this may include further steps to accomplish this. The exterior surfaces of the first sheet portion is preferably activated, such as by rinsing with a solution of sulfamic acid. Activation of the surface of the first sheet portion 38a is desirable to facilitate bonding of additional material thereon by removing oxide or other contaminates from the surface of the first sheet portion 38a. The first sheet portion 38a is then immersed in a plating bath as hereinabove described. A second sheet portion 38b substantially identical to the first sheet portion 38a is then produced with as plurality of elongated enclosed channels formed in the projections of the base layer of the second sheet portion such that the projections of the first and second sheet portions are interdigitated and joined at boundary 52. Since the material of the second sheet portion 38b is elecrodeposited directly on the first sheet portion 38a, the first and second sheet portions form a unitary sheet member with a plurality of elongated enclosed channels. If desired, however, the second sheet portion may be formed as a solid member, without channels, such as to mechanically strengthen the sheet member.

It is to be understood that the rate of deposition of the material may be controlled to alter the size and shape of the channels. For instance, FIG. 7 illustrates the formation of a sheet member with an average current density of 40 amperes per square foot (ASF) applied. The average cross sectional area of the enclosed channels thus produced has been measured at 1.8×10-5 sq. inches (1.2×10-4 sq cm). FIG. 8 illustrates a sheet member formed with the application of an average current density of 80 AF, with an average measured channel cross sectional area of 4.0×10-5 sq. inches (2.5×10-4 sq. cm). FIG. 9 illustrates a sheet member formed with the application of a average current density of 160 ASF, with an average measured channel cross sectional area of 5.2×10-5 sq. inches (3.4×10⁴ sq. cm).

FIG. 10 illustrates an alternate embodiment of the invention in which the mandrel 12' includes projections 41 having conductive surfaces 18, inclined at a negative angle β and edges 15'. The undercut projections require that the mandrel be constructed of a flexible material, such as silicone rubber to facilitate removal, of of a material that may be destroyed during removal without damaging the sheet member. The mandrel shown in FIG. 10 produces a channel 36' having a generally triangular shape. As in FIG. 5, the exposed surface 39' of the sheet member may be ground, or otherwise modified as found convenient.

Of course, it is within the scope of this invention to produce sheet members having channels with any desired cross sectional shape, as predetermined by the shape of the ridge portions on the mandrel used to produce the sheet member as well as the rate of deposition of the material. For instance, the sides of the ridge portions of the mandrel may be perpendicular to the base portion. It is also one of the features and advantages of this invention that sheet members having elongated enclosed electroformed channels having a cross sectional area of any desired size. A sheet member of any desired thickness may be generated. Further, sheet members may be constructed that are flexible so as to be able to closely conform to the configurations of a supportive structure (not shown).

The sheet member of this invention is particularly advantageous if utilized for the circulation of fluids through the plurality of channels. For the purpose of this invention, the term "circulation" includes the transportation, mixing or regulating of fluids. For instance, fluid circulation may be used for heat transfer purposes, to or from an object or area adjacent to or in contact with the sheet member.

Table 1 below illustrates the results of a series of tests performed on a sheet member constructed according to this present invention used for the circulation of fluid for heat transfer purposes. The sheet member was 1 inch×1 inch (2.54 cm×2.54 cm) in dimension and 0.033 inches (0.084 cm) in thickness. The sheet member had 162 channels, each having a cross sectional area of between 5.2×10-5 sq inches (3.4×10-4 cm) and 6.9×10-5 sq inches (4.5×10⁴ sq. cm).

A silicon wafer 0.4" (1.0 cm)×0.6" (1.5 cm) and 0.020" (0.5 cm) thick was soldered to one side of the sheet member by an Indium solder layer 0.005 inches (0.012 cm) in thickness. The silcon wafer was centered alone one transverse edge of the silicone water.

In the tests, power was applied to the silicon wafer as shown in the right hand column in Table 1 below. Fluorinert∼43 (a fluorochemical marketed by Minnesota Mining & Manufacturing Co. of St. Paul, Minn.) was circulated through the channels of the sheet member for conducting heat away from the silicon wafer. The effectiveness of the heat transfer as the applied power is increased is shown in the column entitled "ΔT Chip to Fluid/°Celsius."

TABLE 1
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Flow     Press.
Fluid    Rate     Drop    ΔT Chip
Power
Test  Temp.    gr./sec. N/cm2
to Fluid
Density
No.   °Celsius
cm width cm length
°Celsius
W/cm2
______________________________________
1     22       0        0       65      4
2     25       1.4      2.8      4      7
3     25       1.5      2.8     18      25
4     25       1.6      2.8     24      36
5     26       1.8      2.8     42      64
6     29       1.8      2.8     46      81
7     32       2.0      2.8     56     100
8     32       2.1      2.8     65     121
9     35       2.2      2.8     78     142
10    34       4.2      6.0     64     144
______________________________________

Although not shown, the sheet member 38 of the present invention may be constructed with channels that are non-parallel or non-linear. The depth, angle of inclination, and spacing of the channels may be varied, as desired, and the cross sectional area can vary throughout the length of the channel. For instance, if the circulation of fluids through the channels is for heat transfer purposes, the channels may be concentrated at one or more points within the sheet member to more effectively convey the fluid for heat transfer. Different materials and different deposition rates may be used to construct the first and second sheet portions, if desired.

The present invention has now been described with reference to multiple embodiments thereof. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the present invention. Thus, the scope of the present invention should not be limited to the structures described in this application, but only by structures described by the language of the claims and the equivalents of those structures.

Claims

1. An article for circulating fluids, comprising:

(a) a sheet member having opposing major surfaces; and

(b) a plurality of elongated, enclosed electroformed channels extending through said sheet member between said opposing major surfaces for the circulation of fluids through each of said channels said channels having a predetermined cross sectional shape wherein each adjacent pair of said channels are joined at an undulating boundary extending through said sheet member.

2. The article of claim 1, wherein each adjacent pair of said channels are joined at an undulating

boundary extending through said sheet member. 3. The article of claim 1, wherein said channels are parallel and uniformly spaced with respect to each other within said sheet member.

4. The article of claim 1, wherein one of said major surfaces of said sheet member includes a plurality of projections, each projection containing one of said channels.

5. The article of claim 4, wherein said projections each include at least one side inclined relative to said major surface containing said projections at an angle sufficient to form a taper such that said projection may mesh with at least one corresponding projection when brought into contact with said corresponding projection amd adhere thereto at least partially because of the frictional characteristics of said contacting sides.

The article of claim 1, wherein said sheet member is constructed of an electroformable material selected from the group consisting of nickel,

copper, and alloys thereof. 7. The article of claim 1, wherein at least

one pair of said channels intersect within said sheet member. 8. A method for constructing a sheet member having a plurality of channels, said method comprising the steps of:

(a) providing a mandrel having a base portion and a plurality of elongated ridge portions projecting from the base portion and having elongated edges spaced above the base portion, the ridge portions defining elongated grooves between the ridge portions, and the ridge portions having conductive surfaces; and

(b) electrodepositing a conductive material on the conductive surfaces with the conductive material being deposited on the edges of the ridge portions at a faster rate than on the surfaces defining inner surfaces of the grooves until the conductive material bridges across between the ridge portions to envelope central portions of the grooves and form the sheet member having a base layer and a plurality of elongated projections extending from the sheet member base layer into each of the grooves, with each of the projections containing an elongated enclosed channel ;

(c) separating the mandrel from the sheet member; and

(d) electrodepositing a conductive material on the conductive surfaces of the projections with the conductive material being deposited on the edges of the projections at a faster rate than on the surfaces defining inner surfaces of the grooves until the conductive material bridges across between the projections to envelope central portions of the grooves and form additional elongated enclosed channels in the sheet member.

9. The method of claim 8, further comprising the step of: (c) separating the mandrel from the sheet member.

10. The method of claim 9, wherein the sheet member projections have elongated edges spaced above the base layer, the projections defining elongated grooves between the projections, and the method further comprises the step of:

(d) electrodepositing a conductive material on the conductive surfaces of the projections with the conductive material being deposited on the edges of the projections at a faster rate than on the surfaces defining inner surfaces of the grooves until the conductive material bridges across between the projections to envelope central portions of the grooves and

form additional elongated enclosed channels in the sheet member. 11. The method of claim 8, further including the step of:

passivating the surface of said elongated ridge portions of said mandrel

prior to step (b). 12. The method of claim 10, 8 further comprising the step of:

activating said first major surface of said first sheet portion prior to

step (d) in claim 10 8. 13. An article produced in

accordance with the method of claim 8. 14. An article produced in accordance with the method of claim 10 8.