DE102006043688A1 - Process for producing a hot water storage tank - Google Patents

Abstract

The invention relates to a method for producing a hot water tank (1). According to the invention, this method comprises the following steps: wrapping a possibly preformed plastic body (2) with a fibrous reinforcing material (3), introducing the coated plastic body (2) into a supporting mold (4), closing the supporting mold (4), tempering the supporting mold (4 ), so that the plastic melts, applying a pressure in the interior of the plastic body (2), so that the molten plastic is pressed outwards, and with the surrounding fiber fabric (3) forms a hot water tank (1), curing the resulting hot water tank ( 1) and removal of the resulting hot water tank (1). The inventive method allows a cost-effective, fast and environmentally friendly production of a hot water tank 1, which has a high compressive strength.

Description

The The invention relates to a method for producing a hot water tank.

For certain Purposes, in particular the production of hot water tanks, is the Use of pressure-resistant bodies required. These are preferably made of metal or plastic. Process for the production of pressure-resistant plastic bodies are in Known in the art. Usually becomes a plastic body with a fiber framework surrounded, which solidifies with a resin under the action of heat becomes. The fiber skeleton serves to stabilize the serving as a hot water tank Composite molding and ensures that the composite molding is pressure stable, e.g. if he with liquids filled becomes.

For example, describes the DE 100 07 373 C1 a method for producing sandwich components, in which a resin is first injected into a reinforcing fabric, then melted, and finally cured under pressure.

The DE 196 47 922 C2 describes in this context a method for heating viscous masses, in particular cast resins, by microwave energy.

The Use of resin for stabilizing a fiber composite points However, a number of disadvantages. Thus have plastic containers, the hardened with resin, usually a high weight on. The processing of resins involves a number of problematic substances which make both the production and the recycling less environmentally friendly. About that lets out the resin often difficult to process.

Consequently It is an object of the present invention to provide a process for the preparation a hot water storage to provide, which at avoids problems associated with the use of resins, and at the same time simple, inexpensive and is environmentally friendly.

Is solved the task by a method for producing a hot water tank with the features of claim 1. Advantageous training and further education the inven tion, which used individually and in combination with each other can be Subject of the dependent claims.

The inventive method has the following steps: wrapping, Especially wrap around and / or spanning, possibly a preformed plastic body with a fibrous reinforcing material; Bringing in the wrapped Plastic body in a support form; Shut down the support form; Tempering the support form, so that the plastic melts; Applying a pressure inside the plastic body, so that the molten plastic is pressed outward, and with the fibrous tissue surrounding it forms the hot water reservoir; Curing the resulting hot water storage tank; and removal of the resulting Hot water tank.

In the molding of the plastic body can be chosen between many different shapes. If a plastic body for a tank, for example, desired for a hot water tank, the plastic body is preferably cylindrical. In a preferred embodiment, the plastic body is made of polypropylene, but other materials can be chosen. In a next step, the plastic body is surrounded with the fibrous reinforcing material. The fiber reinforcement is wound around the plastic body or a network of fibers or the like is stretched over it. Continuous fibers can also be used as fiber reinforcement. In a next step, the plastic mold surrounded by the fibrous reinforcing material is introduced into a support mold. This support form is in a preferred embodiment made of steel, but other heat and pressure resistant materials of metallic or non-metallic nature may be used. The introduction of the plastic body is particularly facilitated by the support form is in two parts, but it can also have more parts or be one-piece. In a next step, the support mold is now tempered, that is heated so far that the plastic begins to melt on its outside. It has proved to be particularly advantageous if the temperature is selected such that the plastic becomes soft but not liquid. This allows the plastic to penetrate into the fibers of the fibrous reinforcing material, but it is prevented from liquefying and, following gravity, to accumulate in the lower part of the support form. Now, a pressure is applied inside the plastic body. This can be done by introducing compressed air via a supply line. In this case, various gases or gas mixtures can be used which contain nitrogen, oxygen, carbon dioxide or noble gases. The application of a pressure can take place before, after or simultaneously with the heating. It is particularly advantageous if it takes place simultaneously. As a result, the softened by the temperature plastic material is pressed to the outside. The outer reinforcing fibers remain stable due to their properties and are wrapped and embedded with the outwardly urging plastic. By lowering the temperature curing of the plastic body can now be achieved. Subsequently, the finished plastic body, which is now a composite molding of fiber material and contained therein plastic, are removed. The plastic body now has a pure plastic inner surface and a reinforced area in the outer wall. Thus, the reinforcing fibers can optimally absorb the stress across the plastic matrix. Another way to push the plastic outward into the fibers is to use a centrifugal force to force the plastic material into the reinforcing fibers using a spinning process. It can be dispensed with the application of pressure, but it can also be used simultaneously or successively pressure and centrifugal force to urge the plastic material to the outside in the reinforcing fibers. By means of the process according to the invention, it is possible to produce composite shaped bodies which preferably withstand a pressure load with nominal pressures between 6 and 9 bar.

By the inventive method is opposite achieved a significant improvement in the prior art. Compared to the usual Processes using resin are accomplished by the process of this invention gained much lighter plastic containers. The surface of the Hot water tank has a more homogeneous texture than that of a container that was solidified by means of a resin. This is because of that in the solidification according to the invention of the plastic container by variations of the applied pressure or the temperature curing can be controlled and influenced in a very targeted manner. By renouncing a resin in the production of the plastic container, the plastic container can be easily recycle. In addition, a preparation according to the inventive method cost-effective as is the case in the prior art.

When it has proved advantageous, if in a preferred embodiment as a fibrous reinforcing material a material comprising glass fiber and / or plastic fiber and / or carbon fiber and / or Natural fiber and / or metal fiber is used. These materials are characterized by a particularly high stability and good processability out.

there it is of particular advantage if a material, the silicon carbide fiber and / or aramid fiber and / or polyallylate fiber and / or polyolefin fiber and / or nylon fiber and / or polyester fiber contains is used.

When has particularly advantageous in a very particularly preferred embodiment the use of sisal fibers proved.

In a preferred embodiment is called a fibrous reinforcing material a material comprising at least one fiber selected from a group woven fabrics, knitted fabrics, fabrics, paper, metallic mesh fabrics and porous membranes contains used.

In a particularly preferred embodiment is the plastic body made of polypropylene.

From particular advantage in the production of the hot water tank is it, when tempering the support form a temperature of 150 to 250 ° C, preferably 180 to 220 ° C, more preferably 190 to 210 ° C, and most preferably 200 ° C is used. In these chosen Temperatures of the plastic is soft but not liquid, so that he is in the fibrous reinforcing material can penetrate.

It has proved to be particularly advantageous when the application of the Pressure and / or tempering over a period of 60 to 180 sec, preferably 90 to 150 sec, and particularly preferably one Period of 120 sec is done.

The inventive method allows a cost effective, fast and environmentally friendly production of a composite molding, which has a high compressive strength.

Further Advantages and embodiments of the invention will be described below various embodiments, to which, however, the present invention is not limited, and with reference to the accompanying drawings.

In this show schematically:

1 a representation of a plastic container before the start of the process;

2 an illustration of a plastic container surrounded by fibers;

3 an illustration of a plastic container when inserted into a support mold;

4 an illustration of a plastic container when closing the support mold; such as

5 an illustration of a hot water storage according to the invention after completion of the method.

at the following description of the preferred embodiments In the present invention, like reference characters designate like or comparable components.

1 shows a preformed plastic container 2 before starting the procedure for the production of a hot water tank 1 , Because the container 2 When applying a pressure must be tight, it is advantageous if the plastic container 2 has only one opening. Through this, a compressed air 5 be fed, and in later use, the desired good, such as water filled or removed. The plastic container 2 should have as uniform a wall thickness as possible. In a preferred embodiment, the plastic container contains 2 Polypropylene.

2 shows a plastic container surrounded by fibers 2 , A fibrous reinforcing material 3 was around the plastic body 2 wound. Preferably, a fiber from the group comprising glass fiber, plastic fiber, carbon fiber, natural fiber or metal fiber is used for this purpose.

3 shows a plastic container 2 which is introduced into a support mold. This support form 4 is in a preferred embodiment of steel. The introduction of the plastic body 2 is particularly relieved by the support shape 4 is two-piece.

4 shows a plastic container 2 in a support form 4 after it has been closed. This support form 4 can now be tempered, ie heated so far that the plastic begins to melt on its outside. It has proved to be particularly advantageous if the temperature is selected such that the plastic becomes soft but not liquid. This allows the plastic in the fibers of the fibrous reinforcing material 3 but it is avoided that it liquefies, and following the gravity, in the lower part of the support form 4 reinforced accumulates. Now a pressure is inside the plastic body 2 created. This can be done by introducing compressed air 5 via a supply line 6 respectively. The application of a pressure can take place before, after or simultaneously with the heating. It is particularly advantageous if it takes place simultaneously. As a result, the softened by the temperature plastic material is pressed to the outside. The outside reinforcing fibers 3 stay stable due to their properties and are wrapped and embedded with the plastic that pushes outward. It is particularly advantageous if when tempering the support mold 4 a temperature of 150 to 250 ° C, preferably 180 to 220 ° C, more preferably 190 to 210 ° C, and most preferably 200 ° C is used, and applying the pressure and / or the tempering for a period of 60 to 180 sec, preferably 90 to 150 sec, and more preferably over a period of 120 sec.

5 shows a finished hot water tank 1 after completion of the procedure. The outside reinforcing fibers 3 remain stable due to their properties and are enveloped and embedded by the outward-pressing plastic. On the right side of the 5 is a detail shown. It can be seen that the fibers 3 in the outer area of the container wall 2 are embedded.

The inventive method allows a cost-effective, fast and environmentally friendly production of a hot water tank 1 which has a high compressive strength.

1

Hot water storage

2

Plastic body

3

Reinforcing material, reinforcing fibers

4.a. 4.b

support mold

5

compressed air

6

supply

Claims (8)

Method for producing a hot water storage tank ( 1 ), characterized by the steps: - enveloping a plastic body ( 2 ) with a fibrous reinforcing material ( 3 ); - introducing the coated plastic body ( 2 ) into a support form ( 4 ); - closing the support form ( 4 ); - tempering the support form ( 4 ), so that the plastic melts; - applying a pressure inside the plastic body ( 2 ), so that the molten plastic is pressed outwards, and with the surrounding fiber fabric the hot water tank ( 1 ) forms; - curing the resulting hot water storage ( 1 ); and - removal of the resulting hot water storage tank ( 1 ). Method according to claim 1, characterized in that as a fibrous reinforcing material ( 3 ) a material containing at least one fiber selected from a group comprising glass fiber, plastic fiber, carbon fiber, natural fiber and metal fiber is used. Method according to claim 2, characterized in that as a fibrous reinforcing material ( 3 ) a material containing at least one fiber selected from a group comprising silicon carbide fiber, aramid fiber, polyallylate fiber, polyolefin fiber, nylon fiber and polyester fiber. Method according to one of the preceding claims, characterized in that as a fibrous reinforcing material ( 3 ) Sisal fibers are used. Method according to one of the preceding claims, characterized in that as a fibrous reinforcing material ( 3 ) a material comprising at least one fiber selected from the group consisting of woven fabrics, knitted fabrics, woven fabrics, paper, metallic meshes and porous membranes. Method according to one of the preceding claims, characterized in that a plastic body ( 2 ) containing polypropylene is used. Method according to one of the preceding claims, characterized in that during the tempering of the support form ( 4 ) a temperature of 150 to 250 ° C, preferably 180 to 220 ° C, more preferably 190 to 210 ° C, and most preferably 200 ° C is used. Method according to one of the preceding claims, characterized characterized in that the application of the pressure and / or the tempering over a Period of 60 to 180 seconds, preferably 90 to 150 seconds, and especially preferably over a period of 120 sec takes place.