Down-pumping heat pipes

• US 4,050,509 A
• Filed: 10/28/1976
• Issued: 09/27/1977
• Est. Priority Date: 10/28/1976
• Status: Expired due to Term

• Current Assignee: Dynatherm Corp (Northrop Grumman Corporation)
• Original Assignee: Dynatherm Corp (Northrop Grumman Corporation)
• Inventors: Pravda, Milton F., Bienert, Walter B.
• Primary Examiner(s): Davis, Jr., Albert W.
• Application Number:
  US05/736,548
• Time in Patent Office: 334 Days
• Field of Search: 165/45, 165/105
• US Class Current: 165/45
• CPC Class Codes: F24T 10/30 using underground reservoirs for accumulating working fluids or intermediate fluids
• CPC Class Codes: F28D 15/0266 with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers F28D15/043 takes precedence
• CPC Class Codes: F28F 2200/005 Testing heat pipes
• CPC Class Codes: Y02E 10/10 Geothermal energy

Abstract

Down-pumping heat pipes are provided to augment natural earth heat when used in association with conventional or up-pumping heat pipes for the purpose of maintaining an area such as a roadway free of ice and snow.

Claims

1. A down-pumping heat pipe comprising a pair of angularly disposed upper and lower vessels, an elongated tube enclosed in the lower vessel and providing communication between the vessels, a working agent in the lower vessel able to flow through said tube to the upper vessel, a non-condensible gas in the lower vessel above the level of working agent therein but prevented by said agent from flowing into said tube and upper vessel, and said tube and vessels being substantially evacuated prior to introduction of said agent and gas.

2. A down-pumping heat pipe comprising two angularly disposed vessels one of which is disposable substantially vertically in the ground associated with an area and the other of which is disposable substantially horizontally just below the surface of said area,

a tube enclosed in said ground vessel and at the lower end portion thereof being in communication with such vessel, said tube at the upper end portion thereof being in communication with said area vessel, said tube providing communication between the vessels,

a working agent in the bottom portion of the ground vessel and in said area vessel, an inert non-condensible gas in the ground vessel above the level of said agent, a seal in the ground vessel confining said gas between itself and said agent level,

and said vessels and tube being substantially evacuated prior to introduction of said agent and gas.

3. A down-pumping heat pipe for use in association with an uppumping heat pipe in an area travelled by wheeled vehicles including aircraft, said area in winter time owing to the presence of the up-pumping pipe being capable of maintaining itself free of ice and snow accumulations by utilizing natural earth heat to melt the same and in summer time owing to the presence of the down-pumping pipe being capable of replenishing earth heat by adding thereto heat from the atmosphere and from solar radiation,

said down-pumping pipe comprising two angularly disposed vessels one of which is insertable substantially vertically in the ground below and/or adjacent said area and the other of which is disposable substantially horizontally in the area just below the surface thereof,

an inner tube enclosed by said ground vessel and having an open lower end portion by means of which the tube is in communication with the ground vessel, said tube at its upper end portion being in communication with said area vessel, a quantity of non-condensible gas in the ground vessel,

an amount of working agent in the down-pumping which in summer time is vaporizable in the area vessel by atmospheric and solar heat and is condensible in the ground vessel by the lower temperatures prevailing in the ground, the vaporized agent being able to flow from the area vessel through said tube to the ground vessel where it encounters said non-condensible gas, at least part of the vaporized agent being condensed in said ground vessel, thereby releasing heat of condensation to walls of the vessel and to the surrounding earth, and part of the vaporized agent mixing with said gas in the ground vessel, thereby increasing the pressure of the resulting mixture therein, said gaseous mixture eventually receiving so much vaporized agent as to attain a pressure large enough to force condensed agent back through said tube to the area vessel where it may again be vaporized by the higher temperatures prevailing on the area surface, and said down-pumping pipe being evacuated prior to introduction of said agent and gas.

4. Down-pumping heat pipe of claim 3 wherein the area vessel comprises a chamber in which condensed agent may collect.

5. A combination heat pipe comprising a down-pumping heat pipe having an up-pumping heat pipe incorporated therewith,

said down-pumping pipe having two angularly disposed vessels one of which is disposable in the ground associated with an area and the other of which is disposable just below the surface of said area, an internal seal at an intermediate place in the ground vessel which divides the latter into upper and lower compartments,

an inner tube enclosed in said ground vessel and extending through said upper compartment and seal and into said lower compartment, said tube at its lower end being in communication with the lower compartment and at its upper end in communication with the area vessel,

a first working agent in the bottom of the lower compartment and also in the area vessel, an inert non-condensible gas in the lower compartment above the level of working agent therein, a second working agent in the upper compartment supported on said seal, a vessel extension disposed below said area surface for receiving agent vapors from the upper compartment, and condensate distributing means in the upper compartment having a free unobstructed channel therein,

and said combination pipe being evacuated prior to introduction of said agents and gas.

6. Combination pipe of claim 5 wherein said vessel extension encloses said area vessel.

7. Combination pipe of claim 5 wherein said vessel extension extends angularly of said area vessel.

8. Combination pipe of claim 5 wherein said vessel extension is elongated and said area vessel is disposed at the end thereof.

9. Combination pipe of claim 5 wherein heat-dissipating fins are present in the upper compartment and are supported on said inner tube.

10. In an improved roadway having means for melting ice and snow thereon comprising at least one paving slab supported on a foundation of earth, and wherein said means comprise a plurality of up-pumping heat pipes operatively associated with the roadway,

the improvement comprising a plurality of down-pumping heat pipes operatively associated with the roadway which in warm weather are capable of replenishing earth heat by adding thereto heat from the atmosphere and from solar radiation,

each said down-pumping pipe comprising two vessels one of which is disposable in the grond below and/or adjacent to the roadway and the other of which is disposable in the roadway just below the surface thereof,

an inner tube enclosed by said ground vessel and in communication therewith and also with said roadway vessel, a quantity of noncondensible gas in the ground vessel,

an amount of working agent in the down-pumping pipe which in warm weather is vaporizable in the roadway vessel by atmosheric and solar heat and is condensible in the ground vessel by the lower temperatures prevailing in the ground, the vaporized agent flowing from the roadway vessel through the tube to the ground vessel where it encounters said gas, at least part of the vaporized agent being condensed in the ground vessel, thereby releasing heat of condensation to walls of the ground vessel and the surrounding earth, and part of the vaporized agent mixing with said gas, therby increasing the pressure of the resulting mixture, said mixture eventually receiving so much vaporized agent as to attain a pressure large enough to force condensed agent back to the roadway vessel where it may again be vaporized by the higher temperatures on the roadway surface, and said pipes being evacuated prior to introduction of said agent and gas.