COUPLING PIPE FOR WATER HEATING AND/OR CONDITIONING SYSTEMS AND MAKING METHOD THEREOF

Abstract: The invention relates to a coupling pipe for water heating and/or conditioning systems, of the type having one or more braided layets (2, 3). The main feature of the invention is that the pipe comprises, in the inside of the braided coating thereof, a first and a second tubular layer (4, 5), the first tubular layer being made of a halogenated thermopolymeric material (EPDM), and the second layer being made of a halogen-butylelastomeric material. The present invention also relates to a method for making the pipe.

Description: COUPLING PIPE FOR WATER HEATING AND/OR CONDITIONING SYSTEMS AND MAKING METHOD THEREOF BACKGROUND OF THE INVENTION The present invention relates to a coupling pipe for water heating and/or conditioning systems. The invention further relates to a method for making this pipe. As is known, main requirements for components to be used in heating systems, according to the most recent technical standards, provide that the mentioned components have sealing properties with respect to oxygen, thereby preventing the heating system from being undesirably oxidated. Moreover is also known that the pipe used in the above mentioned applications must have very good strength and flexibility characteristics. In this connection it should be pointed out that at present no rubber pipe having the above properties and a good quality/cost ratio is available. SUMMARY OF THE INVENTION Accordingly, the aim of the present invention is to provide such a coupling pipe for thermohydraulic system which is provided with good physical-mechanical and ageing properties of a EPDM pipe, as well as with the chemical characteristics of a pipe made of a halo-butyl material. Within the scope of the above mentioned aim, a main object of the present invention is to provide such a pipe which has both the properties of the EPDM rubber pipes and those of the pipes made of halo-butyl materials, in particular their tightness to gases. The above aim and objects, as well as yet other objects, are achieved by the present invention which specifically relates to a coupling pipe for thermohydraulic systems, said pipe being of a type including one or more braided coating layers, characterized in that said pipe further comprises, inside said braided coating, a first and second tubular layers, said first tubular layer being made of an EPDM halogenated thermopolymeric material, and said second tubular layer being made of a halo-butyl elasto eric composite material. According to a preferred embodiment of the present invention, the first tubular layer of an EPDM halogenated thermopolymeric material is arranged inside of the second elastomeric layer of an elastomeric halo-butyl composite material. According to a modified preferred embodiment of the present invention, the first tubular layer made of an EPDM halogenated thermopolymeric material is arranged outside of the second elastomeric layer made of a halo-butyl elastomeric material. The pipe of the invention, depending on the mutual arrangement of the two mentioned tubular layers, can be made according to two variations of the same making method. Actually, the present invention also relates, in the case in which the first tubular layer is arranged inside said second tubular layer, to a method for making a pipe for thermohydraulic systems, characterized in that said method comprises at least the following steps: extruding an EPDM halogenated mixture, curing said extruded mixture, cooling and washing the extruded product, concentrically extruding a halo-butyl mixture on the pre-processed EPDM pipe, as well as a first and second coating steps which are respectively performed by braiding a cotton material and further braiding a metal material. According to a preferred embodiment of the present invention, in the case in which the first tubular layer is arranged outside of said second elastomeric tubular layer, the method for making said pipe for thermohydraulic systems, is characterized in that said method comprises at least the following steps: coextruding two elastomeric materials, respectively an EPDM halogenated material and a halo- butyl material in order to provide a first tubular inner layer of a halo-butyl material and a second outer tubular layer of an EPDM halogenated material, curing the thus obtained product in an air oven having controlled temperature and processing time in order to cross-link the elastomeric material, cooling in a vat the extruded product, and performing a first and second coating steps which are respectively carried out by braiding a cotton material and braiding a metal material. The invention provides the following advantages with respect to the prior art status . The pipe of the invention provides very good sealing properties for oxygen, thereby preventing the system from being undesirably oxidated. Moreover, the inventive pipe preserves all of the physical and mechanical properties of the flexible rubber pipes. Thus, the inventive pipe can be assimilated to a single extruded pipe element having a metal coating, which can be easily installed in thermohydraulic system, heating system, conditioning system and the like. BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and characteristics of the present invention will become more apparent from the following disclosure, given by way of an illustrative but not limitative example, with reference to the accompanying drawings, where: Figure 1 is a side view of the pipe specifically designed for thermohydraulic systems according to the present invention; Figure 2 is a further side view of a detail of the pipe according to the invention, clearly showing the inner construction of said pipe, according to a first embodiment of the invention; Figure 3 is a further side view of a further detail of the pipe according to the invention, clearly showing the inner construction thereof, according to a modified embodiment of the invention; and Figure 4 is a further side view of a further detail of the pipe according to the invention, clearly showing the coupling of the two elastomeric tubular layers of said pipe. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following disclosure reference will be made to some preferred embodiments of the present invention, which have been illustrated by way of a not limitative example of several possible variations of the invention. Figure 1 shows the pipe specifically designed for application in thermohydraulic systems, for example heating and conditioning systems, according to the present invention, which has been 5 generally indicated by the reference number 1 and is provided, at the end portions thereof, with pipe fittings 6 and 7. The pipe 1, as shown, comprises and outer braided coating layer 2, made of a stainless steel '0 material and, inside said outer layer, an inner braided coating layer 3 made of a cotton material being further provided. Inside the braided coating layer 3, the pipe 1 comprises a first and second tubular layers, 5 respectively indicated by the reference numbers 4 and 5. More specifically, the first tubular layer 4 is made of an EPDM halogenated thermopolymeric material, whereas the second tubular layer 5 is made 0 of a halo-butyl elastomeric composite material. According to a preferred embodiment of the invention, the first tubular layer 4, made of an EPDM halogenated thermopolymeric material, is arranged inside of the second tubular layer 5 made of a halo- 5 butyl elastomeric material. According to a modified embodiment of the present invention, the first tubular layer 4 is arranged outside of the second tubular layer 5. In particular, the first tubular layer 4 has 30 the following indicative composition: 29.5% elastomeric material, 16% plasticizing material, 34% carbon black, 19& mineral fillings, 1.5% crosslinking or curing agents. This layer has very good hardness, breaking, elongation, wearing, compression set, atmospheric agent ageing, cold and hot water resistance, as well as diluted acid and base resistance properties. The second elastomeric tubular layer 5 has the following indicative composition: 43% elastomeric material, 18% plasticizing material, 23% carbon black, 14.5% mineral fillings, 1.5% crosslinking or curing agents . Moreover, said second elastomeric layer 5 comprises moreover at least 1% bromine. The second layer, as stated, is a halo-butyl elastomeric composite material, providing the pipe with very good oxygen sealing or tightness properties. In this connection it should be apparent that both materials used for forming the pipe do not contain any anti-flaming or anti-firing agents. A perfect binding of the two layers is obtained by a covalent chemical binding, formed with the bromine (Br) component which is present both in the first and in the second tubular layers 4 and 5. Thus , the pipe is very homogeneous and devoid of any binding failures of the two layers which would be susceptible to generate air pockets. Moreover, the AISI 304 stainless steel coating provides the pipe with a very good abrasion, hydraulic pressure resistance as well as with a very good flexibility. The inventive pipe 1, depending on the mutual positions of the two tubular layers 4 and 5, which can be respectively arranged one on the outside of the other or one inside the other, can be made according to two variations of the following making method. In the case in which the first tubular layer is arranged inside the second tubular layer 5, as shown in Figure 4, the method will comprise the following operating steps. The EPDM halogenated mixture is extruded in order to provide the innermost tubular layer, indicated by the reference number 4 in Figure 4. By a drawing operation, under controlled temperature and speed conditions, the tubular layer 4 will be brought to any desired mechanical property arrangement . A conveyor belt will convey the extruded material through a curing or crosslinking oven, of the melt salt type, under controlled temperature and time conditions, thereby allowing the elastomeric material to properly cure, and providing the cured product with the above disclosed mechanical properties. The extruded material will be then brought to a curing and washing vat or tank. The size features of the article of manufacture will be continuously monitored by a laser control equipment, which can control the process according to any suitable fed back procedure. Then, the pipe will be rolled up to form suitable size rolls and conveyed to following processing steps. Then, a concentrical extruding step will be performed on the mixture of the pipe 4 , by a following drawing equipment, operating under temperature and speed controlled conditions, thereby providing the pipe 1 including the two tubular layers 4 and 5. Owing to the specifically designed temperature, pressure and chemical binding conditions used in the making method, the two layers will be perfectly bound to one another. Upon and anti-adhesive process, the pipe will be packaged into rolls, and sent to following possible processing steps. In particular, the first coating is performed by braiding a cotton material 3, while controlling the number, diameter and tension of the threads, as well as the braiding angle and pitch. The thus coated pipe will be then cured in an autoclave under controlled temperature and time conditions. As a following processing step of the method, the pipe will be coated by a metal braid 2, using stainless steel threads or wires, and controlling the number, diameter and tension of the wires, as well as the braiding angle and pitch. As a last processing step, cutting operations will be performed and fittings will be assembled in order to allow the formed pipe 1 to be easily installed in the system provided for its application. On the contrary, in the case in which the first tubular EPDM layer 4 is arranged outside, of the second elastomeric tubular layer 5, as shown in Figure 2, the operating steps will be as follows. The two elastomeric materials are co- extruded by an extruding die, under controlled temperature and speed or rate conditions, thereby providing a pipe 1 having any desired size. Thus, the pipe will be simultaneously provided with an inner layer formed of the halo-butyl polymeric material and an outer layer formed by an EPDM halogenated material. A conveyor belt will convey the extruded pipe to a curing oven, preferably of the air circulating type, under controlled temperature and time conditions, thereby providing a cured pipe having the above disclosed desired physical-mechanical properties . The extruded pipe will be then sent to a cooling vat or tank. In this operation, the size of the pipe will be continuously monitored by any suitable monitoring equipment, i.e. a laser control equipment, which can operate according to any known feedback procedure. Then, the pipe 1 will be packaged into rolls and sent to possible following processing steps. As a following processing step of the method, the pipe will be provided with a metal braid 2 made of stainless steel wires, while controlling the number, diameter and tension of the wires, as well as the braiding angle and pitch. As a last processing step, the pipe will be cut to any desired length, and fittings 6 and 7 will be assembled for allowing the finished pipe to be easily installed. From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects.

Claims: CLAIMS 1. A coupling pipe for vater heating and/or conditioning systems, of a type including one or more braided coating layers, characterized in that said pipe comprises, inside said braided coating, a first and second tubular layers, said first tubular layer being made of an EPDM halogenated thermopolymeric material and said second tubular layer being made of a halo-butyl elastomeric composite material. 2. A coupling pipe for water heating and/or conditioning systems, according to Claim 1, characterized in that said first tubular layer is arranged inside of said second tubular layer. 3. A coupling pipe for water heating and/or conditioning systems, according to Claim 1, characterized in that said first tubular layer is arranged outside of said second tubular layer. 4. A coupling pipe for water heating and/or conditioning systems, according to one or more of the preceding claims, characterized in that said first tubular layer has the following composition: 29.5% elastomeric material, 16% plasticizing material, 34% carbon black, 19% filling materials, 1.5% cross- linking materials. 5. A coupling pipe for water heating and/or conditioning systems, according to one or more of the preceding claims, characterized in that said second layer has the following composition: 43% elastomeric material, 18% plasticizing material, 23% carbon black, 14.5% mineral fillings, 1.5% crosslinking materials. 6. A coupling pipe for water heating and/or conditioning systems, according to Claim 5, characterized in that said second layer further comprises at least 1% bromine. 7. A coupling pipe for water heating and/or conditioning systems, according to one or more of the preceding claims, characterized in that said pipe comprises moreover, outside said tubular layers, a first braided layer made of a cotton braided material. 8. A coupling pipe for water heating and/or conditioning systems, according to one or more of the preceding claims, characterized in that said pipe comprises moreover, outside of said tubular layers, a second braided coating layer made of a metal braided material. 9. A method for making a coupling pipe for water heating and/or conditioning systems, said method being characterized in that it comprises at least the following steps: extruding an EPDM halogenated mixture, curing the extruded product, cooling and washing in a vat the extruded product, and concentrically extruding a halo-butyl mixture on the previously processed EPDM-halogenated material pipe, and a first and second coating steps being respectively carried out by braiding a cotton material and braiding a metal material. 10. A method for making a coupling pipe for water heating and/or conditioning systems, according to Claim 9, characterized in that said EPDM halogenated mixture extruding step provides to use an extruding die operating under controlled temperature and rate conditions, for providing an inner tubular layer having set mechanical dimensions. 11. A method for making a coupling pipe for water heating and/or conditioning systems, according to Claim 9 or 10, characterized in that said concentrical extruding step of said halo-butyl mixture on said EPDM-halogenated material pipe is carried by a further extruding die operating under controlled temperature and rate conditions . 12. A method for making a coupling pipe for water heating and/or conditioning systems, according to one or more of Claims 9 to 11, characterized in that said curing step is carried out in molten salts and under temperature and time controlled conditions in order to allow said elastomeric material to properly crosslink. 13. A method for making a coupling pipe for water heating and/or conditioning systems, according to Claim 9, characterized in that said method comprises at least the following steps: coextruding two elastomeric materials, . respectively an EPDM halogenated material and a halo-butyl material to provide a first inner tubular layer made of a halo- butyl material and a second outer tubular layer made of an EPDM halogenated material, curing the thus obtained product in an air oven under controlled temperature and time conditions to allow the elastomeric material to cure, cooling in a cooling vat or tank the extruded product, as well as a first and second coating steps being respectively carried out by braiding a cotton material and a metal material. 14. A method for making a coupling pipe for water heating and/or conditioning systems, according to Claim 13, characterized in that said coextruding step is carried out by an extruding die operating under controlled temperature and rate conditions, to provide an extruded pipe having any set mechanical dimension. 15. A method for making a coupling pipe for water heating and/or conditioning systems, according to one or more of Claims 9 to 14, characterized in that in one or more of said steps, the size of said pipe is continuously monitored by a laser monitoring apparatus, operating on a feedback procedure. 16. A method for making a coupling pipe for water heating and/or conditioning systems, according to one or more of Claims 9 to 15, characterized in that in one or more of said coating braiding steps, the number, diameter, tension of the braiding threads and/or wires, as well as the braiding angle and pitch are continuously monitored. 17. A method for making a coupling pipe for water heating and/or conditioning systems, according to one or more of Claims 9 to 16, characterized in that, following said first coating braiding step, said pipe is cured in an autoclave, under controlled temperature and time conditions .

Inventors: PRESSI ANGELO, PRESSI, ANGELO
Applicants: HYDROGOMMA S R L, PRESSI ANGELO, HYDROGOMMA S.R.L., PRESSI, ANGELO
Application year: 1999
Main classification: F16L11
IPC codes: F16L11