COVER FOR AN OUTDOOR TANK

Abstract

The invention relates to a cover for an outdoor tank, the cover being made of a plate that can be treaded on and shifted between an open and a closed position, wherein the cover is guided displaceably on rails for opening and closing purposes in an at least approximately parallel fashion to the opening surface of the tank. A seal acting between the cover and the edge surface of the tank is brought into contact with the corresponding surface during the closing motion by such a relative movement that has a clear directional component, said directional component being normal on and directed toward said surface. The temperature of the surface from which the seal is removed when the cover is opened is automatically monitored and automatically raised by a heating element when the temperature falls below the freezing point.

Description

The invention relates to a movable rigid cover for an outdoor tank, for example a swimming pool.

DE 297 09 674 U1 discloses a cover, in particular for swimming pools, formed from at least one rigid, flat board which is designed to be moved via rollers on rails. In the form described therein, the board consists of Plexiglas; between the edge of the swimming pool and the board there extends a brush seal. When the swimming pool is open, the board is retracted under a cover arranged next to the swimming pool. This cover protects and covers the board and the rail region on which it is moved.

A disadvantage of this type of construction is that, primarily in cool, sunless weather, a great deal of heat can be lost even from the covered swimming pool, because in that case the amount of heat introduced through the Plexiglas is much less than the amount of heat lost through heat flux. The brush seal is highly mechanically loaded by the relative tangential movement of the board with respect to the edge of the swimming pool and when it is detached at sub-zero temperatures, and is rapidly destroyed. All kinds of leaves, earth and pests rapidly gather in the cavity beneath the cover. It is difficult and time-consuming to keep this cavity clean.

DE 2005 009 842 U1 discloses a swimming pool cover which is made of a flat board, can be walked on and can be moved on rails. The cover is preferably arranged in a plane with a surrounding terrace area and covered with the same covering. The rails are arranged in depressions in or on the terrace area. The proposed design appears optimized such that the swimming pool is emptied and covered over in the colder half of the year but the terrace area can still be used. There is no discussion regarding the problem of heat loss from the swimming pool and the movability of the cover even in snowy conditions.

The object of the invention is to improve the cover according to the described prior art for an outdoor tank, typically a swimming pool, which cover consists of a flat board which can be walked on and can be moved on rails, such that even when it is snowy and cold it can be opened and closed easily and without damage and such that the heat loss from the tank is minimized.

One or more of the following improvements are carried out in order to achieve the object with respect to the type of construction in accordance with the prior art:

• • The seals which act, when the cover is completely closed, between the latter and the edge of the tank are moved, with that part (tank edge or cover) against which they come to bear during the closing process, by such a relative movement toward this part, which movement has a large normal component to the surface of this part against which the seals are brought into abutment. When the cover is opened the reverse sequence takes place. That is to say, first the seals are disengaged by a movement with a large normal component to the sealing surface to be opened and only then is the cover pushed away.
  • The advantage achieved thereby is that damaging sliding movement between the seal and the surface toward which the seal must be brought during the closing process or from which it must be separated during the opening process is avoided.
  • The surfaces from which the seals must be detached when the cover is opened are automatically heated by a frost monitor.
  • This prevents the seals from freezing solid. Seals that seal very well but are otherwise mechanically sensitive and made of flexible plastics can thus be used.
  • Rails on which the movement of the cover is guided during opening and closing and also the surface region between the rails which is located next to the tank are freed of ice and snow or are permanently kept free thereof, as required, by integrated heating.
  • The result of this is that the cover can also be opened and closed as required in winter without problems.

The invention, further details relating thereto and practical developments are described with the aid of drawings which show an advantageous embodiment of the invention in somewhat stylized form:

FIG. 1: is a vertical sectional view of an embodiment of the invention in the application as a whirlpool. The cover has been opened about half way. For reasons of clarity the earth is assumed to be transparent and not, as is otherwise conventional for sectional planes, shown as hatched.

FIG. 2: shows the arrangement in FIG. 1 from above.

The cover 1 is a rigid, flat and horizontally arranged board. In an advantageous embodiment it is formed from a stainless steel frame which is filled or lined with a thermally insulating material. On its top it is provided with a ground covering in line with the customer's wishes, for example with wooden planking. On its underside the cover 1 is provided with wheels 3 which roll on a pair of stationary rails 4. The two rails 4 run parallel to one another on either side of the tank to be covered 5, over its entire length.

The movement of the board can be driven in a very convenient embodiment by way of electric motors, which drive the wheels 3 and can be switched on and off remotely. By omitting components, simpler embodiments of this embodiment can be created, right down to the one in which the cover 1 is simply pushed by hand. In embodiments driven by a motor, for safety reasons a stop sensor should be provided which, starting at a particular resistance, either switches off the drive or switches to movement in the opposite direction when an obstacle is encountered.

A seal 2 is mounted at the edge of the lower surface of the cover 1, which seal bears with its side facing away from the cover 1 against the edge 5.1 of the tank to be covered when the cover is closed. According to the invention, there is provision to make the edge 5.1 heatable, in the region of that surface part against which the seal 2 bears, by means of a heating device, for example an electric heating wire arranged just under the surface, and to monitor the temperature at this surface region using sensors. By means of the heating device, the temperature of this surface part is then kept at least just above freezing point.

In order that the seal 2 is not stressed at the surface 5.1 by being pulled in a direction tangential to the surface 5.1, it is only moved toward the surface 5.1 at the end of the closing movement of the cover by a relative movement with respect to the surface 5.1, which movement has a substantial component normal to the surface 5.1. In the illustrated example, this is brought about by the stepped design of the rails 4. In most of the longitudinal region of the rails the rolling surface for the wheels 3 of the cover 1 is aligned parallel to the surface 5.1 and arranged at such a level that the seal 2 attached to the cover is raised so far above the surface 5.1 that it does not touch the latter. Only in that longitudinal region of the rails 4 at which the wheels 3 are located when the cover 1 is closed is the rolling surface of the rails lowered with respect to the surface 5.1 to such an extent that the seal 2 bears against the surface 5.1. The transitions between the raised and the lowered parts of the rolling surface on the rails are formed as relatively short, that is to say steep ramps 4.1. When the cover is closed, the cover only drops down in the very last part of the closing movement, that is to say a movement of the cover toward the surface 5.1, which movement has a substantial component in the direction normal to the surface 5.1.

The approaching movement of the seal to the surface 5.1 with a substantial directional component normal to the surface 5.1 can of course also be brought about by means other than a curved rolling surface on the rails. The seal itself can be moved relative to the cover toward the countersurface on the tank edge once the cover has been pushed over the tank into the closed position. By way of example, the seal may for this purpose be attached to a profiled bar mounted on the cover such that it can rotate in its profile plane. For closing, the profiled rod is rotated such that the seal bears against the edge surface of the tank. For opening, the profiled bar is moved away from said surface again. It is of course also possible to attach the seal to a bar which is moved normal to its longitudinal direction linearly toward the corresponding surface of the tank edge.

In order that the opening and closing movements of the cover are not impeded by ice or snow, the rails 4 and the surface region 10 between the two rails that is located next to the tank are also provided with a heating device by means of which ice and snow can be melted as required. For the rails, this heating device may in turn consist, for example, of an electric heating wire or of an electric heating film arranged thereon. For the surface region 10, conventional undersoil heating systems based on hose loops through which a heat-transfer medium flows can be provided.

A typical whirlpool is a tank filled with water, the wall surfaces of which are formed such that the users are provided with seating formed such that, when they sit on it, only their head protrudes from the water and they are massaged by jets of water and/or blown-in air from a multiplicity of nozzles. The water is heated to a comfortable temperature. It is conventional to treat the water by means of filters and chemical treatment, for example by means of ozone, continuously such that it does not need to be changed for a relatively long time, for example a year.

The structure according to FIG. 1 and FIG. 2 is advantageous primarily for heated outdoor whirlpools that can be used throughout the year.

An outer tank 5 is mounted supported on a foundation and surrounded by earth. In an embodiment which is advantageous because it is durable, its surfaces are constructed in the manner of a sandwich from in each case one external stainless steel sheet and an insulating layer spanning the interspace, made for example of PU foam. The actual whirlpool 6 is installed in this tank 5. The whirlpool does not cover the entire inner area of the tank, rather free space 7 remains in the tank 5, from which space necessary maintenance work on the whirlpool 6 or on additional appliances mounted thereon can be carried out if appropriate. In addition, the tank 5 still has the very important function of thermal insulation between the outside of the whirlpool 6 and the surrounding earth. When the cover is closed the space in the tank 5 is closed off in an airtight manner from the external air by the seal 3, which then bears against the edge 5.1 of the tank. The tank 5 considerably simplifies the installation sequence compared to the conventional type of construction in which the walls of the depression required for sinking the whirlpool have to be concreted in the earth.

In order that the whirlpool can be used at any time without a long lead time, the water contained therein is kept warm constantly. In order that the heat loss during those times in which the whirlpool is not being used and the cover 1 is closed is kept as low as possible, an additional thermally insulating layer 8 is arranged on the underside of the cover 1 in that region located directly over the whirlpool, which layer, when the cover is closed, bears either directly or by way of a circumferential soft seal against the upper edge of the whirlpool. When the insulating layer 8 bears directly against the whirlpool, it should be made from a flexibly resilient material, for example a resilient plastic foam, at least in the region where it touches the whirlpool. The same considerations as above for the seal 2 between the cover and the edge 5.1 of the outer tank 5 apply for the movement of the cover during closing and opening with respect to this seal arrangement.

In order to enable simple visual monitoring of the whirlpool, in an advantageous embodiment the cover 1 and the insulating layer 8 located thereunder are provided with an opening penetrating both surfaces, which opening is closed by a highly thermally insulating tread-resistant insulating glass panel 9.

Claims

1. A cover for an outdoor tank, which cover consists of a board, can be walked on and can be moved between an open and a closed position, wherein, in order to open or close the cover, the latter can be moved guided on rails at least approximately parallel to the opening surface of the tank, wherein a seal is attached to one of the two parts, cover or edge surface, of the tank, irrespective of whether the cover is open or closed, and comes into contact with a sealing surface at the second part when the cover is closed and is released therefrom when the cover is opened, characterized in that, during the closing process, the seal is brought into contact at said second part by such a relative movement with respect to the surface, which movement has a clear directional component which is normal to this surface and is directed toward the latter, and in that the temperature of that surface from which the seal is released when the cover is opened is monitored automatically by a temperature sensor and is raised automatically by a heating device arranged in the vicinity if the temperature falls below freezing point.

2. The cover as claimed in claim 1, characterized in that the rails on which the movement of the cover is guided during opening and closing are heated by a heating device arranged in their vicinity.

3. The cover as claimed in claim 1, characterized in that the surface region between the rails which is located next to the tank is heated by a heating device arranged thereabove or therebelow.

4. The cover as claimed in claim 1, characterized in that the cover is provided with rotatable rollers by means of which it rests on stationary rails such that it can travel, wherein those longitudinal regions of the rails on which the rollers lie when the cover is closed are lower than the adjacent longitudinal regions of the rails, directed toward the tank bottom, in the direction of the opening movement.

5. The cover as claimed in claim 1, characterized in that the seal is attached to a profiled bar which is mounted such that it can rotate about an axis parallel to its longitudinal direction.

6. The cover s claimed in claim 1, characterized in that the seal is attached to a profiled bar mounted such that it can move linearly parallel to its profile plane.

7. The cover as claimed in claim 1, characterized in that it extends over an outer tank in which a smaller inner tank is arranged, wherein only the inner tank is filled with water, wherein the surfaces of the outer tank are designed to be thermally insulating and wherein at least one horizontal external dimension of the inner tank is much smaller than the horizontal internal dimension of the outer tank in the same direction.

8. The cover as claimed in claim 7, characterized in that it is provided on its underside, in that surface region which is over the inner tank when the cover is closed, with an additional thermally insulating layer compared with other surface regions of the cover, which additional layer rests on the edge of the inner tank directly or by way of a seal when the cover is closed.

9. The cover as claimed in claim 7, characterized in that it is provided, in the region of that surface which is over the inner tank when the cover is closed, with an opening closed by a tread-resistant insulating glass panel.

10. The cover as claimed in claim 7, characterized in that the inner tank is a whirlpool.