The present invention is for a shower floor grating with flow preheating for raising of the temperature of the cold water inflow.

At showering inflowing hot and cold water is mixed so that the desired temperature is obtained of the water which flows out from the nozzle of the shower. The amount of hot water which is consumed is directly depending upon the temperature of the inflowing cold water which therefor also decides the amount of heat which is consumed och the cost for this. The inflowing cold water may be heated by heat exchange with the outflowing used shower water so the that the consumption of heat is reduced and the cost is lowered. It is then essential that the heat transfer to the inflowing water is as efficient as possible. In order to make the heat recovery profitable also at small units such as individual showers it is also required that the costs for the necessary equipment is low in absolute figures as also the costs of installation. The device must also be easy to clean as this is of importance from hygienic points of view and also for the function of the device.

Showers often have a low shower basin which means that a small volume of water is collected in the basin during the showering. Means for heat recovery are known at which tube meanders a put into the shower basin and during the showering become immersed into the used water before it flows out over an outflow brim. However, such devices have turned out to be unsatisfactory for heat recovery and they have important hygenic disadvantages as skin flakes, hair etc. easily collects on the tubes.

The present invention is for a shower grating having flow preheating by which the above mentioned disadvantages may be avoided and an efficient preheating of the inflowing cold water is achieved. The invention has the characterizing features which are apparent from the first claim. Embodiments of the invention has those characteristics which are apparent from the other claims.

The invention will below be described more in detail with reference to the not limiting example of an embodiment which is shown in the enclosed figures.

Figure 1 is a top view of a shower grating according to the invention.

Figure 2 is a bottom view of the shower grating.

Figures 3 and 4 are cross-sections of parts of the shower grating.

The shower grating 1 has a standing floor 7 and a downward outer border 6. The outer dimensions of the shower grating are adapted to the space which is available, this often means a square or rectangular shape with a side length of 600-1000 mm. The grating may also have legs 2 which extend themselves further down than the border 6 so that water which occurs outside the shower grating may flow in underneath it to a draining gutter. The standing floor 7 has a number of long slit openings 4 and is otherwise closed. The outer border 6 preferably extends itself both upwards to prevent flow of water over the sides and downward somewhat below the standing floor 7.

A meandering tubular coil 3 is mounted at the underside of the shower grating. The tubular coil is held by mounting means so that it is a short distance underneath the underside of the standing floor 7 and at least so far above the flooring that the tubular coil is not in direct contact with the water which collects or flows on the flooring. By the tube connection 5 the tubular coil is so connected that inflowing cold water is fed to it and after heat exchange is fed to the shower device to be mixed with inflowing hot water. The tube connection 5 and the mounting means for the tubular coilare designed so that the entire tubular coil may be released from the mounting means and turned around at the connection 5 so that the tubular coil and the underside of the shower grating become accessible for cleaning. In order to further facilitate cleaning the connection between the shower grating and the in-and outflowing water preferably is a pressure resisting hose so that the shower grating as a whole may be lifted up from the flooring.

The slit openings 4 of the standing floor form the same pattern as the meandering tubular coil which is positioned directly underneath the slit openings. Between them the standing floor is shaped as a domed surface or in cross section, as shown in figures 3 and 4, upward curved surface the top point of which is between two adjacent, parallel slit openings. This means that all water is controlled so that it after a short dwell time at the standing floor rapidly is transferred to the tubular coil and flow around it so that the tubular coil is continuously washed by the flowing water. As the used shower water immediately flows on to the slits and through these down at the tubular coil it is further achieved that the dwell time of the water at the standing board will be short and heat losses to the surroundings will be small. The curving of the surface may vary within

wide limits, also a small curving will sufficiently influence the flow of water to ensure the proper function of the device.

For hygienic and other reasons the standing floor 7 and the borders 6 of the shower grating 1 are made as one piece with soft bending of corners and edges so that dirt and bacteria not can cumulate.

Inflowing cold water usually has a temperature of 4-8 °C, using a shower grating according to the invention this may be raised to more than 20°C, which means a reduction of the consumption of hot water by up to 30%. This in turn means that the cost for the shower grating for an average family may correspond to reduced costs for hot water during a period as short as one year.

Other embodiments of the shower grating are possible within the frame of the inventive idea. The sections between the slit openings may be of different cross section conditional to that it meets the requirements of directing the flow of water on the standing floor as desired. The tubular coils may have another shape than that described above where the slit openings and the tubular coil shall be adapted to one another as described above. The tubular coil may also in other ways be mounted to and releasable from the standing floor. The shape of the standing floor may be circular, triangular or irregular and the shape of the tubular coil is to be adapted to the standing floor in a suitable way. The cross sections of the tubes may differ from the circular shown in the figures, for example drop-shaped when the point of the drop preferably is pointing down. These and other embodiments are also included in the invention.