Patent Application
20220364794
The present invention relates generally to a heat pipe structure, and more particularly to a heat pipe structure having an ice molecule force releasing space for a frozen working fluid.
A conventional heat pipe has a hollow case (tube) body. A capillary wick is disposed in the case (tube) body. A working fluid (such as water, coolant, methanol, acetone and liquid ammonia) is filled in the case (tube) body. In the current market, the hollow case (tube) body is generally made of copper, aluminum or the like material. The working fluid in the hollow case (tube) body will change between different phases to release latent heat so as to transfer heat.
The heat pipes currently applied to electronic products for dissipating heat are all made of copper tube with pure water therein. The copper has better heat conductivity and the working fluid has better latent heat so that such heat pipe meets the use requirements of most of normal environments. However, the application of the heat pipe is still limited by the application conditions, for example, outdoor heat dissipation application (such as 5G, 6G base station, outdoor photovoltaic power supply IGBT heat dissipation and vehicle heat dissipation). Also, the freezing problem of the working liquid in a zero-degree environment and the affection of the ice molecule force to the structural strength will limit the application of the heat pipe.
When the heat pipe is horizontally arranged and the working fluid is frozen, the ice molecules will expand to pressurize and expand the tube wall of the heat pipe. This will lead to deformation of the heat pipe. On the other hand, in the case that the heat pipe is vertically arranged, the working liquid will accumulate on the bottom of the lower end of the heat pipe due to gravity. When the environmental temperature is lower than zero degree, the working liquid in the heat pipe will freeze and the ice molecules will expand to expand the wall face of the heat pipe. In some more serious situations, the heat pipe will be expanded and broken to lose the vacuum state and leas to leakage of the working fluid.
It is therefore tried by the applicant to provide a heat pipe structure having an ice molecule force releasing space for a frozen working fluid so as to solve the above problem of the conventional heat pipe that the working liquid in the heat pipe will freeze at low temperature to destroy the vapor-liquid circulation in the heat pipe.
It is therefore a primary object of the present invention to provide a heat pipe structure having an ice molecule force releasing space for a frozen working fluid. In the case that the heat pipe is vertically arranged, the working liquid will accumulate on the bottom of the lower end of the heat pipe due to gravity. The working liquid filled in the heat pipe will freeze at zero degree. At this time, the releasing force of the ice molecules of the frozen working liquid on the lowermost portion of the heat pipe will expand the bottommost portion of the tube body. In this situation, the ice molecule force releasing space of the heat pipe provides a space for the frozen working fluid so as to prevent the heat pipe from breaking.
To achieve the above and other objects, the heat pipe structure of the present invention includes a tubular body. The tubular body has a first end and a second end and an airtight chamber. At least one capillary structure layer is disposed on a wall face of the tubular body. A working fluid is filled in the airtight chamber. Any of the first and second ends of the tubular body is such arranged as to be normal to a horizontal face. The first and second ends are respectively positioned at upper and lower ends of the tubular body. One end of the tubular body in contact with the horizontal face has a bulged space as an ice molecule releasing space after the working fluid is frozen.
In the case that the heat pipe is vertically arranged, the working fluid will accumulate at the lower end of the heat pipe due to gravity. The environmental temperature of the actual working site ranges from 40˜100 degrees. When the environmental temperature is lower than zero degree, the working liquid filled in the heat pipe will freeze. The water and ice have different physical densities so that the molecule releasing force of the ice at the lower end (or the heat pipe) in the vertical direction will expand the tube wall of the bottommost portion of the heat pipe. The heat pipe structure of the present invention is formed with the bulged space as an ice molecule releasing space after the working fluid is frozen so as to prevent the tube body of the heat pipe from breaking.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein:
Please refer to
The tubular body 1 has a first end 11 and a second end 12 and an airtight chamber 13. At least one capillary structure layer 2 is disposed on a wall face of the tubular body 1. A working fluid 3 is filled in the airtight chamber 13. The working fluid 3 is selected from a group consisting of water, coolant, methanol and acetone. The capillary structure layer 2 is selected from a group consisting of sintered powders, channels, woven meshes and any combination thereof. The tubular body 1 is selected from a group consisting of circular tube, flat tube and square tube. The tubular body 1 is made of a material selected from a group consisting of aluminum, copper, stainless steel and titanium. Any of the first and second ends 11, 12 of the tubular body 1 is such arranged as to be normal to a horizontal face. That is, the tubular body 1 is vertically disposed. The first and second ends 11, 12 are respectively positioned at upper and lower ends of the tubular body 1. One end of the tubular body 1 in contact with the horizontal face has a bulged space 14 as an ice molecule releasing space after the working fluid 3 is frozen.
The bulged space 14 of the tubular body 1 has a capacity larger than that of any other portion of the tubular body 1. The bulged space 14 is formed in such a manner that the tubular wall of the tubular body 1 upright upward protrudes to form an expanded space. Alternatively, the bulged space 14 is formed in such a manner that the tubular wall of the tubular body 1 horizontally leftward or rightward protrudes to form an expanded space.
The problem solved by the present invention is that when the heat pipe is vertically used, the working fluid will accumulate at the lower end. At this time, in the case that the environmental temperature is lower than zero degree, the working fluid in the heat pipe at the lower end will be frozen so that the portion of the heat pipe in which the working fluid is frozen will be expanded or even exploded and broken. Therefore, in the present invention, when the heat pipe is vertically used, the bulged space 14 is formed at the lower end of the heat pipe as an ice molecule releasing space after the working fluid is frozen. Alternatively, both of two ends of the heat pipe can be formed with the bulged spaces 14. Still alternatively, the bulged space 14 can be formed on any portion of the heat pipe in accordance with the use state of the heat pipe.
The present invention has been described with the above embodiments thereof and it is understood that many changes and modifications in such as the form or layout pattern or practicing step of the above embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.
