Abstract The two preferred and illustrated embodiments set forth downhole tool cooling systems. In a downhole oil well tool exposed to extremely high working temperatures, a cooling system is provided for the printed circuit boards and various electronic components thereon. In one embodiment, the cooling system incorporates a closed container having a bottom located sump, a pump for picking up and pumping liquid refrigerant from the sump, and a distribution line extending from the pump to spray the PC boards with refrigerant. Cooling is accomplished on vaporization, and refrigerant flows back to the bottom as it condenses. In the alternate embodiment, no pump is included. Rather, a heat sink is included at the top of a closed and thermally isolated chamber. The bottom includes a sump for refrigerant. In between, a mesh distributes droplets of condensing liquid over the surfaces of the PC boards to accomplish cooling.
A method of cooling electronic components in a downhole tool comprising the steps of: (a) initially filling a sump within a downhole tool with liquid refrigerant; (b) moving a portion of the refrigerant from the sump to be applied directly to the surfaces of electronic components in a chamber above the sump by vaporizing said refrigerant in said sump by contacting said liquid refrigerant in said sump directly with at least some of said electronic components; (c) constraining the flow of vapor from the liquid refrigerant vaporized by absorbing heat from said electronic components, and directing the vapor against a cooling surface means to be converted into droplets of condensed refrigerant; and (d) flowing said condensed refrigerant droplets across said electronic components and vaporizing the liquid refrigerant to cool said components.
Claim 2
Independent Claim
131 words
A method of cooling electronic components in a downhole tool comprising the steps of: (a) initially filling a sump within a downhole tool with liquid refrigerant; (b) moving a portion of the refrigerant from the sump to be applied directly to the surfaces of electronic components in a chamber above the sump by vaporizing said refrigerant in said sump by contacting said liquid refrigerant in said sump directly with at least some of said electronic components; (c) constraining the flow of vapor from the liquid refrigerant vaporized by absorbing heat from said electronic components, and directing the vapor against a cooling surface means to be converted into droplets of condensed refrigerant; and (d) flowing said condensed refrigerant droplets across said electronic components and vaporizing the liquid refrigerant to cool said components.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said cooling surface is an electrically operated cooling surface as a thermoelectric device.
Claim 4
Dependent Claim
50 words
The method of claim 1 wherein the step of cooling said electronic components by vaporizing the liquid refrigerant to be applied directly to the surface of said components includes flowing liquid refrigerant under the influence of gravity flow along surfaces of an open weave mesh directly contacting said electronic components.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein said cooling surface means comprises a closed housing containing a material absorbing heat on achieving a change of state from solid to liquid.
Claim 6
Dependent Claim
26 words
The method of claim 4 wherein said absorbing material comprises a eutectic alloy having a melting temperature cooler than the temperature of vaporization of said refrigerant.