US 2937009 A
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May 17, 1960 R. L. ANDERSON PIPE NON-FREEZE! PROTECTOR 2 Sheets-Sheet 1 Filed Nov. 28, 1958 INVENTOR.
ATTORNEYS May 17, 1960 R. L. ANDERSON PIPE NON-FREEZE PROTECTOR 2 Sheets-Sheet 2 Filed Nov. 28, 1958 Pober'f L Anderson INVENTOR.
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A 770/?N VS 2,937,009 PIPE NON-FREEZE PROTE CTOR Robertv L. Anderson, Houston, Tex. Application'November 28, 1958, Serial No. 777,003 6 Claims. (Cl. 257122)' The present invention relates to an apparatus for preventing pipes from freezing, and more particularly, relates to such apparatus for protecting from freezing water pipes that extend above the ground frost line by utilizing the heat from the ground below the frost line. The exposure of'water pipes to freezing temperatures above the ground frost line results in the freezingfof the water thereby rendering the water conductors inoperative and often results in expensive damage. Presently used methods for providing non-freeze protection consist of retarding the heat dissipation by means of insulation or by providing an expensive buried cut-off valve located below the frost line with a drain hole below the frost line at the valve seat to release the water from the riser when the valve is closed. Pipes using the insulating method will eventually freeze without the addition of heat and the buried cut-off method results in maintenance difliculties below the ground surface and still has thepossibility of freezing due to stoppage of the drain hole. It is'to overcome these disadvantages that the present invention is directed.
It is an object of this invention to provide an apparatus ,for preventing pipes from freezing by the utilization of heat from the ground.
A further object of the present invention is the .provision of an apparatus for continuously transferring heat from areas of high temperature to areas of low temperature.
Yet a still further object of the present invention is the provision of an apparatus for protecting from freezing water pipes that extend above the ground frost line that require no moving parts.
Yet a still further object of this invention is the provision of an apparatus for protecting water pipes from freezing by utilizing the ground heat to vaporize a liquid which will carry the heat above the frost line and there give up the heat, condense, and return by gravity to repeat the cycle.
Uniw State Pateflfo Other andfurther objects, features and advantages I will be apparent from the following description of a presently preferred embodiment of the'invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings, where like character references designate like parts throughout the several views, and where v Figure '1 is a sectional'elevational view illustrating an apparatus according to the invention,
Figure 2 is an enlarged sectional elevational view illustrating a method of supporting the heat transfer tube inside a water pipe,
Figure 3 is a cross-sectional view along the line 3-3 of Figure 1,
Figure 4 is a side elevational view, partly in cross-section, illustrating a modification of the present invention in which the heat transfer tube is extended within the horizontal water supply pipe,
Figure 5 is a side elevational view, in cross-section,
illustrating another modification of thepresent invention inwhich the heat transfer tube is on the outside of the water pipe,
Figure 6 modification of the present invention having the transfer tube on. the outside of the water pipe, 7
Figure 7 is an enlarged cross-section taken along the line 77 ofFigure 6. V
Referring now touthe drawings. and particularly Figures 1,2 and 3, the reference numeral 10 designates a conventional water pipe which extends underground, usually beneath the frost line 14, and provides an outlet above the ground level 16, here shown as a water hydrant 12 (Figure 1). The temperature below the frost line 14-is above freezing and the pipe 10 below this line needs no protection; however, when the pipe extension above the frost .line 14 is subject to freezing temperatures both below and above the groundit is in need of protection. j
Referring now to Figure 1, a heat transfer tube 18 is provided inside the water pipe 10 and extends from below the frostline where ground temperatures are higher to the top of the piperiser 11. The heat transfer tube 18 includes a hermetically sealed tube with a liquid 29 and saturated vapor .31 in equilibrium. The liquid 29 in the tube absorbs heat from the ground below the frost line which vaporizes the liquid, usually at the liquid surface 30, causing the heat to be transferred within the tube 18 to the top by the natural convection of the vapor where it gives up its heat of vaporization to the water. in
pipe riser 11 by conduction and thereby condenses and re turns to its starting positionin the cycle by gravity. By providing sufficient heat transfer surface on the tube 18 contacting. the warmer soil below the freezing line 14, heat lost to the atmosphere and to the frozen ground by the water in-the pipe riser 11 will be offset by heat flowing from. the ground where ground temperatures are higher than the temperature within the protected pipe and the average temperature of the water is maintained above freezing temperature.
The liquid and its vapor used within the heat transfer tube 18 is preferably a chemical compound or a mixture of chemicals that is stable, nontoxic, non-corrosive and has the desirable thermodynamic properties of low pressures, high latent heat of vaporization, and low specific volume of vapor.
used such as dichlorodifluoromethane, more commonly known as Freon 12.
One method of providing suflicient heat transfer service below the freezing line is to extend the heat transfer tube 18 vertictally down into the ground below normal ditching depth which both provides more heat transfer surface and reaches higher ground temperatures since the ground temperature increases with increasing depths. For example, as shown 'in Figure 1, a conventional pipe T 19 may be inserted between the pipe riser 11 and the underground water pipe 10 with the heat transfer tube 18 extending vertically through the T 19 down into the ground. As 'shown'a protective jacket 25 may be provided and attached to the conventional pipe T 19 to both protect and provide a driving point for ease of installation.
As best seen in Figure 2, the transfer tube 18 is held in the pipe riser 11 by means of a support 20 which rests on the end of riser 11. As seen in Figures 1 and 3, spacing supports 22 attached to the riser 11 may be provided if desired to center the transfer'tube 18 in the is a sectional elevational view of another For example, any of the refrigerants normally used in refrigerated drinking fountainscould be shown provide a means which facilitate the ease of removal'and insertion of the heat transfer tube 18 for inspection or replacement.
In extreme climates where heat losses would .be relae tively large, or where relatively large area of piping is exposed, an insulation 26'and outer cover 28 may be provided to prevent excessive heat loss and reduce the amount of heat transfer surface required of the transfer tube 18 below the freezing line 14. It is noted that the insulation 26 and outer cover 28 are not provided below the frost line 14 as they are only used to prevent the heat from escaping from the pipe riser and not to prevent heat below the frost line 14 from entering into the protection system.
Another method of providing sufficient heat transfer surface, as best seen in Figure 4, is by extending a transfer tube 18a in'the pipe riser 11 through the pipe and within the horizontal supply pipe 10 which is buried below the frost line. The tube 18a may be easily inserted and removed by pushing the flexible tube 18 into the pipe riser 11, around elbow 15 and into ground pipe 10. This method has the advantage of requiring no special construction other than the heat transfer tube and the insulation where the piping-is exposed to extreme freezing temperatures, but requires more heat transfer tubing 18 than the installation of Figure 1 because the ground temperatures are not as high as those encountered using the vertical installation of Figure 1.
As best seen in Figure 5 another modification shows a heat transfer tube 18b provided outside and around the pipe riser 11 instead of inside as shown in Figures 1-4. In Figure 5 the underground water supply pipe enters the heat transfer tube 18b through a sealed opening 34 and the pipe riser 11 is spaced concentrically in the transfer tube 32. The lower end of the tube 18b has a protective cap and driving point 33 so that it may be driven into the ground from normal ditching depths. If desired the heat loss from the pipe riser 11 may be reduced by providing insulation above the frost line 14. An internal insulation 38 may be provided within the heat transfer tube 18b so long as a sufficient space 36 is provided for the transfer of heat to the pipe riser 11.
Figures 6 and 7 is another modification which encloses the pipe riser concentrically with a heat transfer tube and is similar to Figure 5 except that a tube 180 extends beneath the ground in a horizontal direction around the supply pipe 10 to obtain sufficient heat transfer surface. If desired, insulation may be provided such as air spaces or vacuum spaces 40 and 42 internally in the heat transfer tube 180 above the frost line 14. These partitions for the air space may be made of aluminum to prevent excessive radiation losses.
In use, the heat transfer tubes 18, 18a, 18b and 180 which are thermodynamically associated with pipe risers 11 extend into the ground beneath the frost line 14 where the Warmer temperatures are found and where there is less seasonal variation of temperatures. The heat transfer tubes may be inside the water pipe risers 11 as shown in Figures 1-4 or outside and surrounding the pipe risers 11 as shown in Figures 5-7 and extend below the frost line 14 in any manner desired so as to provide sufficient heat transfer surface and soil volume below the freezing line. Thus, the heat lost by the water in the pipe riser 11 to the atmosphere and to the freezing ground is offset so that the average temperature of the water in'the' riser 11 is maintained above, freezing temperature. The sealed heat transfer tubes 18, 18a, 18b and contain a liquid 29 and saturated vapor 31 in equilibrium. A' decrease in temperature of .the water in the pipe riser 11 would cause condensation of the vapor 31 on the interior surface of the tubes 18, 1821,1817 and 180 causing a release of the heat of vaporization. The condensate will flow by gravity towards the base of the heat transfer tube where upon indirect contact with the higher temperatures in the ground, the condensate would again absorb heat, rise to the top 30 of the liquid 29 in the heat transfer tube by gravity and vaporize. Of course, if SllfllClIlt heat were available the vaporization process would occur below the liquid surface 30 or possibly the condensate would vaporize even before it returned to the base of the transfer tube. .Thus a continuous process is established where the heat is transferred from the ground to within the sealed tubes 18, 18a, 18b and 18c and the water in the pipe riser 11' is maintained above freezing temperature.
For purposes of illustration the invention shown herein is shown in this application to water pipe risers having water hydrants. This is intended by way of example only, and this invention is capable of use for all types of water service rising from the ground such as lawn hydrants, sprinkler heads, drinking fountains, box type wall hydrants, and other devices using a pipe riser which is subjected to freezing temperatures either in the ground or above the ground.
The present invention, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned as well as others inherent therein. While presently preferred embodiments of the invention are given for the purpose of disclosure, numerous changes in details of construction, arrangement. of parts may be made which will readily suggest themselves to those skilled in the art which are encompassed within the spirit of the invention and the scope of the appended claims.
What is claimed is:
1. An apparatus for protecting from freezing a water.
pipe that extends above the ground frost line comprising a hermetically sealed tube extending from below the frost line to a position above the frost line adjacent the Water pipe, and a mixture of liquid and saturated vapor in said tube whereby heat is transferred from below the frost line to the water pipe that extends above thefrost line.
2. The invention of claim 1 wherein the liquid has the thermodynamic properties of low pressures, high latent heat of vaporization, and low specific volume of vapor.
3. The invention of claim 1 wherein the tube is positioned inside the water pipe.
4. The invention of claim 2 wherein the tube is positioned inside the water pipe. I
5. The invention of claim 1 wherein thetube is positioned outside and around the water pipe.
6. The invention of claim 2 wherein the tube is positioned around and outside the water pipe.
References Cited in the file of this patent UNITED STATES PATENTS 2,164,677 Banke July 4, 1939