DE3007524A1 - Pressurised storage tank - with gap between blow moulded plastic liner and glass fibre wrapping filled by resin - Google Patents

Abstract

A cylindrical pressurised storage tank esp for instantaneous water heaters, is made by preparing a blow moulded plastic liner which is fitted with reinforcing caps top and bottom and surrounded in a wrapping machine by a braiding of resin impregnated glass fibre strands. The gap, created by shrinkage during the subsequent curing between liner and braiding, is filled with a fluid resin by applying a suction at one and allowing it to set. The compensates for any shrinkage of the liner which is caused by the curing operation.

Description

Method of manufacture

of a pressure storage container The invention relates to a method for the production of a pressure storage tank, especially for a water heater with a blown inner container (liner) with a plastic-soaked fiberglass wrapping is provided and the wrapping is cured under heat.

A plastic container made by such a method is, is described in DE-GM 74 12 817. This container is on the polar caps Stiffening parts put on, which are covered by the wrapping. To a uniform support of the stiffening parts on the inner container is to be achieved a hardening filler layer between the stiffening part and the inner container, especially one Adhesive layer, provided. This is before the Placing the stiffening parts on the tops of the inner container.

The plastic-soaked fiberglass wrapping is after the application hardened on the inner container under the action of heat. It has been shown that the inner container shrinks in the process. So it forms a cavity between the Inner container and the wrapping.

Under the operating conditions to be invoiced for a hot water heater with pressure fluctuations and temperature changes, for example between i4 0c and 85%, the inner container will expand and shrink in the cavity. Such a freedom of movement for the inner container is unfavorable because it the fatigue strength of the inner container is reduced.

The object of the invention is to provide a method of the type mentioned at the beginning To propose kind, with which the storage container can be built so that the shrinkage inevitably occurring during the hardening of the wrapping during operation of the inner container does not have an adverse effect.

According to the invention, the above object in a method is that initially mentioned type solved in that after curing between the inner container and a flowable plastic compound is introduced into the wrapping. The flowable Plastic compound fills the cavity that is created during hardening. She works with it in operation as a buffer between the inner container and the fiberglass wrapping.

In a preferred embodiment of the invention, the plastic compound introduced in that a negative pressure in the cavity between the inner container and Wrapping is generated and the plastic mass under the influence of the negative pressure flows into the cavity.

Further advantageous refinements of the method emerge from the following description. The drawing shows a storage tank schematically on average.

A blown plastic inner container 1 is after putting on clamped by stiffening parts 3 and 4 in a winding machine. The one stiffening part 4 has a flange opening 5 into which an electric heater, for example, is located and a flange carrying a temperature sensor can be inserted.

In the winding machine 1 plastic-soaked on the inner container Wound glass fiber strands. The winding is done so that one of the inner container 1 wrapping encompassing radially to the circumferential direction and one the stiffening caps 3 and 4 overlapping diagonal cross wrapping is created.

After the wrapping 6 has been applied as a whole, the container 1 for hardening the plastic that impregnates the glass fibers in a drying oven drove. In the course of hardening the wrapping 6 shrinks due to the action of heat the inner container 1 inevitably.

It arises between the inner container 1 and the e.g.

Wrapping 6 a cavity 7. The cavity can be 2 mm high in the radial direction of the longitudinal axis of the container and a height of 5 mm in the crown area reach with nominal dimensions of approx. 90 cm height and approx. 40 cm after hardening of the Wrapping 6 is either in the area of the stiffening part 3 or the stiffening part 4 a suction bell is placed, via which a negative pressure is generated in the cavity 7. On the opposite stiffening part, a storage container with a flowable Plastic compound applied. Under the effect of the negative pressure it becomes flowable Plastic mass is sucked into the cavity 7 until it is practically completely filled is.

The flowable plastic compound could also be in bring in the cavity. In the process described, which works with negative pressure however, a more uniform distribution of the plastic compound in the cavity 7 is achieved.

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Claims (2)

Claims method for the production of a pressure storage container, especially for a water heater, with a blown inner container (liner) is provided with a plastic-soaked fiberglass wrapping and the wrapping is cured under the action of heat, characterized in that after curing A flowable plastic compound is introduced between the inner container and the wrapping will. 2. The method according to claim 1, characterized in that for introduction the plastic compound creates a negative pressure in the cavity between the inner container and the wrapping is generated and the plastic mass under the influence of the negative pressure in the cavity flows.