FR2478161A1 - Frost-resistant pipe for domestic water feed - contains e.g. tube of compressible sealed cellular material which contracts when ice forms - Google Patents

Abstract

The pipe (11) is used to convey fluid esp. water and may be incorporated in central-heating systems. It houses intermittent or continuous compressible packings (12). The volumetric relationship between the pipe and packings (12) is such that, should the water freeze, the expanding ice will compress packings with pipe damage obviated. Packings (12) have a multi-cellular closed and sealed structure containing a compressible flux e.g air. Packings may have a round cross section and may contact (12a) pipe bore to leave a crescent shaped area (13) for the water, or may have radial ribs defining an annular gap. Core cords (16) may connect packings at intervals, and alternative packings may have an annular or a spoked wheel cross-section.

Description

 The invention relates to conduits, enclosures or containers for fluids, in particular liquids, and more particularly those with a function of protection against freezing and heat exchanger.

 Before approaching the main provisions of the invention, it is necessary to recall the difficulties encountered with containers or conduits for liquids, when they contain or convey liquids which can freeze, and in particular water.

 Degradation of containers, and mainly water lines, by freezing, poses problems that have been attempted in various ways.

 In the case of water supply pipes, circulating outdoors, or even central heating installation pipes, external insulation of the pipes is used and, if the installation is not used, it is emptying.

 In some cases, antifreeze products are also used which are mixed with water, for example glycol, which lowers its freezing point.

 In other cases, the water is heated with an energy supply, which is always a solution containing water.

 These antifreeze protection methods, more or less adapted to different conditions of use, all have drawbacks.

 Thus, if the insulation is effective, it requires a down payment in material and manpower. Furthermore, this protection method is totally unsuitable for conduits with a heat exchanger function such as conduits for solar collectors, radiator conduits.

 In addition, the emptying prior to a temporary deactivation of the circuit of an installation must not be forgotten because, when a partial or total return to service, damage occurs.

It is known in fact that an undrained central heating installation runs, on the one hand significant risks from freezing, and on the other hand, that a drained circuit is strongly attacked by the internal oxidation of the circuit.

 In other types of installation, automatic emptying of the circuits is sometimes provided, in particular in the solar collectors.

 The automation requires expensive thermostatic equipment, error-free adjustment and the absence of an electrical failure which would have the effect of draining the circuit, even if it was at its highest temperature.

 The antifreeze-water mixture can only be used in a closed circuit (flooded primary circuit), which heats up exchange losses and the use of additional equipment. This process is therefore a fairly limited use.

 Finally, heating a liquid from a critical temperature goes against energy savings.

 The present invention is based on the observation of a phenomenon known per se. Everyone knows that a corked bottle containing water does not explode if it is not completely full, provided that the amount of air left inside is greater than the expansion of the freezing water. However, an amount of air in a container or a free duct poses many problems because, on the one hand, the air can besides hindered with the current of @ au, on the other hand, its presence in circuits is undesirable since many installations must be purged of air under penalty of malfunction and performance.

 One could also consider on the conduits, the installation of air bells, of the kind against ram strokes, but their installation and heavy number eréoraiont of significant costs to which are grafted @ iont problems of size and aesthetics .

 We tried to make several antifreeze devices based on the presence of a compressible fi nm fi nir arranged in a duct. We refer in particular to French patent application No. 78. 08218 of March 13, 1978 in which we design a prot @ction @refrost, for @@ p @ eur s @ l @ ire, @ ara @ lérlsée en @@ that a small tube in rubber @ or in semi-rigid plastic, filled with air and hermetically sealed at its two ends with a length close to that of the tubes to be protected against frost, is placed inside each of the tubes to be protected.

 In this arrangement, the compressible tube has a much smaller section than the passage section of the tube to be protected, which does not make it possible to produce a heat exchanger with low inertia and high efficiency.

 Furthermore, it is practically impossible to maintain the sealing of such air chambers over time, so that the antifreeze function is quickly neutralized.

 The present invention therefore has for its object a duct, an enclosure or a container which cancels the harmful effects of the gel and is, in addition, a heat exchanger with low inertia and with improved efficiency, and whose antifreeze function remains constant over time.

 Another object of the invention is to provide a container or conduit of simple construction, of low cost, no longer requiring emptying in the freezing period and which can, at any time, be put back into operation quickly, even in the event of freezing of the liquid contained or conveyed.

 The invention relates for this purpose a conduit or container for fluids and in particular liquids, such as water, internally comprising one or more bodies capable of withstanding compression, and absorbing the expansions generated by the gel, characterized in that these compressible bodies consist of a structure comprising a plurality of sealed closed cells, containing a compressible wire, and in that the free passage section for the circulation of the liquid is at least equal but preferably less than the section occupied by the body compressible.

 By this arrangement, the liquid undergoing the effect of the gel, can expand by decreasing the volume of the body in compressible material, this ice to which, the duct or container no longer absorbs the expansion forces generated during the gel, the air occluded in the cells cannot escape, and it is possible to constitute a heat exchanger of the water blade type with very low thermal inertia.

 According to an arrangement of the invention, in its exchanger function, the profile of the body of compressible material is produced so as to leave at least one blade of liquid between the internal wall of the duct and this body.

 According to another arrangement, the compressible body is concentric with the internal wall of said conduit.

 In another case, the compressible body partially or entirely lines the internal wall of the container or conduit.

Other characteristics and advantages of the invention will emerge from the following detailed description of an embodiment of the invention given here by way of example, and represented by the accompanying drawings in which
Figure I is a perspective view with parts broken away showing an embodiment of the invention.

 Figure 2 is a perspective view with parts broken away showing another embodiment.

 Figure 3 is an axial sectional view of a pipe showing another embodiment.

 Figure 4 is a perspective view showing another arrangement of the invention.

 Figure 5 is a perspective view showing a container equipped with a compressible body in particular for the release of a solidified liquid.

 FIG. 6 is a perspective view showing an example of a compressible body applied to an enclosure with flat walls, of the exchanger or flat sensor type.

 As shown in Figures 1 to 4, there is shown the embodiment in which the invention is applied more particularly to pipes or enclosures for frost protection, or to pipes or exchanger enclosures, the protection function against freezing and the exchanger function which can also be combined in the same pipe.

 These different types of pipes are designated by the general reference 10.

 In the embodiment of FIG. 1, the rigid rigid pipe li has in its internal passage a body of compressible material 12, arranged so as to leave a space between this body and the internal wall 11a of this pipe. 13 with liquid circulation.

 According to one arrangement, the compressible body 12, which is here in the form of a log, is arranged eccentrically with respect to the axis of the conduit II, so that one of its generators 12a, is at contact of the internal wall of the duct 11. In this case, a lamellar space is created between the compressible body and the wall ila of the duct for the passage of a sheet of water whose cross section is in the form of a crescent, this whereby the passage of water on a sector of the conduit is deliberately limited, which makes it possible to obtain in a simple manner, an exchanger which finds an advantageous application in the constitution of a circuit capable of being integrated into a solar collector.

 The body of compressible material may further be wrapped in a flexible or elastic skin, and waterproof 12b, not degrading with water, and non-toxic, natural or synthetic, and which may include closed air cells.

 The core of this body can be constituted for example by a gas, by a more or less honeycombed foam, with closed cells, if it is not enveloped by the waterproof skin 12b.

 In the embodiment of Figure 2, the compressible body 12 is arranged concentrically with the inner wall 11a of the conduit.

The compressible body is centered in the duct 11, by means of edges or grooves 14; distributed around the periphery of this body, so as to come into contact with the corresponding generatrices of the wall 11a of the conduit II
Los ridges or cannoluros delimit between it back
lamellar passages 13n. Co modo do realization finds an application
main to the constitution of water pipes equipped against frost,
but can also find an application to the realization of elements
exchangers, of the type leaf radiator.

In the embodiment of Figure 3, we have shown a
embodiment in which the compressible body 12 is constituted
of a succession of segments 15a, 15b, 15c, which can vary in shape
and in dimensions. Whatever the embodiment adopted, an axial reinforcement 16 is provided with the compressible body, an armature which serves both to stiffen the compressible body, to facilitate its introduction into a duct, or to serve to center the segments of compressible material. in the tube, as shown in Figure 3.

 In general, the material of the compressible body must be sufficiently rigid, on the one hand to avoid its compaction, especially at the elbows of the conduits, in order to avoid obturation by deformation, on the other hand, so that the pressure of the liquid itself does not compress this compressible body to the point that an ice formation, for example, leaves no room for the expansion caused by the freezing of the liquid.

This compressible material must also keep a stability of consistency sufficient to adapt to the applications envisaged.

 To avoid the compaction of these compressible elements by the sole action of the conveyed liquid, the compressible material can be retained upstream of the current by any process, for example an extensible clip 17. It is also possible, as has been said, to equip the interior of the material compressible by a rigid or semi-rigid reinforcement. At the elbows of the pipes, an extension of this frame will not be wrapped in compressible material. it goes without saying that the section of the compressible body and that of the tubes will be calculated as a function of the flow rate and of the pressure of the liquid, of the compressibility coefficient of the material introduced into the pipe, and also, as a function of the temperatures of use.

 On the other hand, in an exchanger, if the profile of the compressible bead can have different shapes, it will be designed in any case, so that it ensures a maximum exchange surface along the internal wall of the tube, such as by example, a solar collector absorber tube; it should then have a flow section placed on the exposed side as shown in figure I.

 In the case of an exchanger tube, as shown in Figure 2, the bead must allow a film of fluid to slide between the compressible material and the metal. Thus, exchanges will be facilitated, and in the event of frost, the film of ice formed will be much more quickly melted than a cylinder filling this tube, and also much more easily reheated than a liquid filling it.

 In the embodiment of FIG. 4, the compressible body 12 lines the internal wall of the conduit II, leaving a free axial passage 18.

 In the embodiment of Figure 5, the compressible body 12, which lines the internal wall 19 of a container 20 is divided by several radial partitions 21. Thanks to this arrangement, the compressible body can be used in particular for demolding a solidified liquid in the free sectors of the compressible body.

 Likewise, as shown in FIG. 6, it is possible to design a heat exchanger, or a solar collector with a flat enclosure 22, equipped with compressible material 23, distributed by points or uniformly inside this enclosure.

 In this case, the flexible material 24 may consist of two deformable waterproof sheets, glued to each other, trapping in place gas or compressible air cells.

Among the main applications of this kind of conduits or containers, we will note in particular:
domestic, industrial or agricultural drinking water installations exposed to frost,
central heating installations,
heat, heat and frigorlfiquos exchangers,
] solar etiptours,
transport of cold or solidified liquids.

Blen @ n @@ ndu, the invention n '@ st. not @@ mitée to the examples of execution @ l above deerlts and représontés, for losquels one could envisage other variants, without cola going beyond the framework of the appended claims, thus in the preceding examples, the compressible bodies can obviously be formed not only of spongy materials, but also of flexible membranes containing gas or air, delimiting the lamellar passage as shown in FIG. 2.

 No compressible materials suspended in the liquid can be used, these materials will absorb expansion during freezing.

Claims (9)

 1) Conduit or container for fluids, and in particular liquids such as water, internally comprising one or more bodies capable of withstanding compression and absorbing the expansions generated by the gel, characterized in that these compressible bodies consist of a structure comprising a plurality of sealed closed cells, containing a compressible flow, and in that the free passage section for the circulation of the liquid is at least equal, but preferably less than the section occupied by the compressible body.  2) Duct or container according to claim I, character  laughed at in that in its exchanger function, the body profile in matter  compressible is made so as to leave between the wall  internal of the conduit and this body, at least one blade of liquid.  3) Duct or container according to any one of  Claims 1 and 2, characterized in that the compressible body is  concentric with the internal wall of said duct.  4) Duct or container according to any one of  claims I and 2, characterized in that the compressible body is  eccentric so that part of its surface is in contact with  the inner wall of the duct.  5) Duct or container according to any one of  Claims I to 4, characterized in that the compressible body comprises  a continuous axial reinforcement.  6) Duct or container according to any one of  claims 1 to 5, characterized in that the compressible body is  consisting of segments carried by the axial reinforcement.  7) Duct or container according to claim 6  characterized in that the compressible body covers all or part  the inner wall of the conduit or container.  8) Duct or container according to claim 7, characterized in that the peripheral part of the compressible body which lines the internal wall of the duct to the container is divided by one or more radial partitions.  9) Duct or container according to claim 1, characterized in that it is in the form of a flat enclosure in which the compressible body consists of a sealed alveolate envelope capable of containing a gas in its alveoli.