Electric Sauna Unit

Abstract

In an electric sauna unit there is a nozzle for sprinkling water over heated stones in a stone receiving chamber. The bottom of this chamber forms a trough collecting water which has not vaporized, and an electric heating element extends into this trough. The supply of water is controlled by a valve operatively connected with a thermostatic element exposed to the external heat radiation from the bottom of the trough. Instead of a thermostatic switch for controlling the water supply, this can be achieved by a bimetallic spring arranged adjacent the bottom of the cabinet and mechanically connected to a control valve. In the water conduit may be disposed a manually disposed throttle valve. The water control valve may be a solenoid valve which is periodically opened and closed.

Description

The present invention relates to electric sauna units having a chamber for heat accumulating bodies and heating elements for the heating of said bodies, and a nozzle connected through a valve to a water conduit disposed for sprinkling the heated bodies with water. Owing to this sprinkling of water -- the so-called bath-sprinkling, which in most cases is done by scooping water on the heated bodies -- there will be a damp saturated atmosphere in the sauna room. After the bath-sprinkling the humidification percentage falls relatively fast, which however, is not always desirable. Many people prefer to keep the humidification percentage in the sauna room at a constantly high level.

It is an object of this invention to keep by simple means a high damp humidification percentage in the sauna room by recurrent, automatic bath-sprinkling, and this is achieved by an electric sauna unit comprising a chamber for receiving heat accumulating bodies and forming a trough at the bottom thereof, a heating element for heating the bodies extending into the trough, a nozzle for sprinkling water over the heated bodies, a conduit for connecting the nozzle to a water supply, a valve in the conduit for controlling the flow of water therethrough, and thermostatic means for sensing heat radiation from the cavity and operatively connected with the valve for controlling the closing and opening thereof.

Means in the form of a bimetallic switch is provided for periodically opening and closing the water control solenoid valve. If desired, thermostatic valve control means may be mechanically connected to the water control valve. Furthermore, a manually adjustable throttle valve may be provided in the water supply conduit.

The invention will be described in detail below with reference to the accompanying drawings, in which

FIGS. 1 and 2 are two vertical sectional views perpendicular to each other, partly in diagrammatical side view, of an electric sauna unit according to the invention;

FIG. 3 is a circuit diagram for the arrangement according to the invention;

FIG. 4 is a side view, partly in vertical section, of the nozzle device;

FIGS. 5 and 6 are elevational views of the arrangement for fixing the nozzle in different operating positions;

FIG. 7 is a partial sectional view in accordance with FIG. 2 of a modified embodiment and

FIG. 8 is a view similar to FIG. 3 showing an adjustable throttle valve in the water supply conduit and eliminating the bimetallic switch.

The sauna unit shown in FIGS. 1 and 2 comprises a sheet casing 10, forming a vertical air passage 11 open at the bottom and at the top. In the passage there is disposed a chamber 12 for heat accumulating bodies, 12a for instance stones, and electric heating elements 13 -- one for each phase in a three-phase supply -- extending partly through the passage 11 to heat the air therein resulting in a flow of air from below and upwards through the passage, and partly through the chamber 12 to heat the bodies placed therein. By connections 14 the electric heating elements are connected to a thermostatic switch or other thermostatic means sensing the temperature in the sauna room. So far, the sauna unit shown is of a known embodiment.

According to the invention the bottom portion of the chamber 12 is formed as a watertight cavity such as a trough 15, and there is a nozzle 16 inserted into the chamber 11 through an opening 17 in the casing 10 and a corresponding opening 17a in the chamber. By a conduit 18 the nozzle 16 is connected to a water conduit 19 through a solenoid valve 20. When this solenoid valve 20 is open, water is supplied through nozzle 16 into the spaces between the bodies 12a which are heated by means of the heating elements 13 inside the chamber 12 and is vaporized to so that there will be a damp atmosphere in the sauna room. Water supplied which is not vaporized flows down into the trough 15. One of the heating elements 13 extends down into and along this chute for immediate vaporization of the water accumulating in the chute and this, element should be one that is constantly switched on. In case there are disposed three heating elements for a three-phase supply, one or two of these may be periodically switched off and on simultaneously or separately in dependence on the sensing of the temperature in the sauna room, while the third heating element -- that one extending into the chute -- is constantly switched on. For the control of valve 20 there is disposed a thermostatic switch 21, the sensing body of which is arranged at the underside of the bottom of the trough 15 in order to be exposed to heat radiation therefrom. If the trough does not contain any water, the heat radiation from its bottom is greater than when water is accumulated in the trough. The thermostatic switch 21 has connection conduits 22, and in the diagram according to FIG. 3 it is shown how it is connected to the solenoid valve 20.

According to FIG. 3 the thermostatic switch 21 is connected to an electric power source 23 in series with a switch 24, the solenoid of the solenoid valve 20 and a bimetallic switch 25. The unit is operative when switch 24 is closed. The thermostatic switch 21 is arranged in such a way that it is closed at a temperature above a predetermined value, and is open when it is at a temperature below said value. This value is chosen in such a way that the thermostatic switch 21 is open when there is water in trough 15 -- no water can be supplied provided that the solenoid valve 20 has to be energized to open -- and is closed when it is exposed to stronger heat radiation such as when there is no water in the trough 15. The bimetallic switch 25 is supposed to be normally closed but is opened when it has been closed for a predetermined period due to current flowing through the circuit connected to the power supply thereby breaking this circuit. Then it is closed again after a predetermined period. Thus, the bimetallic switch 25 closes and opens the circuit periodically.

Assuming that the heat radiation from trough 15 is sufficient to make the thermostatic switch 21 close, the circuit connected to the power supply 23 will be closed the solenoid valve 20 thereby being energized to open. Water is then sprayed into chamber 12 and is vaporized. After a certain period the bimetal switch 25 will open so that the solenoid valve 20 is reclosed, and after a new interval the bimetal switch 25 will close again so that the solenoid valve 20 will open for repeated supply of water. The water supply to the chamber 12 through the nozzle 16 is thus provided by impulses as long as the thermostatic switch 21 is closed. Owing to the bimetal switch 25 being adjustable in respect to the relation between the intervals of the closed and open conditions the flow of water may be controlled by such adjustment. Should not all of the water supplied be vaporized at once when in contact with the heated bodies in the chamber 12, water will run down into chute 15 and thus the heat radiation to which the thermostatic switch 21 is exposed, will be reduced resulting in a fall of the temperature sensed by the thermostatic switch. This switch is then opened so that the water supply ceases until the water in the trough 15 has been vaporized, whereupon the process is reiterated. Any overdose of the water sprinkling is prevented by this process.

Instead of the bimetallic switch 25 there may be arranged in the conduit 18 as shown on FIG. 8 an adjustable throttle valve 30, by means of which the flow through the nozzle 16 can be controlled. In such a case the solenoid valve 20 is constantly open as long as the thermostatic switch 21 is closed.

FIGS. 4 to 6 show how nozzle 16 is preferably arranged in the sauna unit. The latter may be intended for delivery without the device for the water supply, which may then be available as a separate auxiliary unit. The opening 17 is made in the sheet casing 10 but is covered by a closure plate 26, pivoted on the casing by means of a rivet 27. On delivery of the sauna unit, the plate 26 covers the opening 17, as is seen in FIG. 5, in order to prevent a jet of hot air being directed through this opening against the wall behind the sauna unit, to which the unit is mounted. The nozzle 16 has a flange 28 that is larger than the opening 17, and owing to the plate 26 being removed from the opening 17, the nozzle 16 may be inserted into the chamber 12 through the opening to bring the flange 28 into contact with the outer surface of the sheet casing such as is shown in FIGS. 4 and 6. Thereupon, the plate 26 is swung down into contact with the nozzle on the outside of flange 28, i.e. to the position illustrated by dashed and dotted lines in FIG. 6, thus keeping the nozzle in its position in the chamber 12. If desired, several alternative positions for fitting the nozzle 16 may be provided by arranging openings 17 at different levels in the casing 10 with corresponding openings in the chamber 11 so that the nozzle can be arranged at the level providing the best sprinkling effect. Of course, the nozzle 16 may be permanently mounted on the sauna unit. By an adequate choice of the opening area of the nozzle the desired adjustment of the humidification in the sauna room can be obtained.

The occurrence of water in the trough 15 may be sensed by other means than a thermostatic switch 21. According to FIG. 7 such sensing may be made by means of a thermostat 29 such as a bimetallic spring immediately adjacent or disposed on the underside of the bottom of the chute 15 and mechanically connected to the valve 20 in order to operate the valve member of the valve.

In certain cases, for instance in well insulated sauna rooms provided with an oversized electric sauna unit, the heating elements 13 may be deenergized for long periods. During these periods the humidification percentage in the sauna room may fall considerably. To eliminate this drawback, there may be disposed in the trough 15 a separate electric heating element that is continuously energized to vaporize the water accumulated in the chute but having such a low power that it does not have any noticeable effect on the temperature in the sauna room. The same arrangement may be used when there is disposed only a single heating element 13 or when several heating elements 13 are arranged but are simultaneously switched on and off.

Claims

What I claim is:

1. An electric sauna unit comprising

an upright tubular casing open at the top and bottom to provide a vertical air passage,

a housing within said air passage and around which an air stream flows, said housing forming a chamber for stone-like heat accumulating bodies,

a nozzle extending inside said chamber for sprinkling water over said heat accumulating bodies to create a vapor,

a water tight trough in the bottom of said chamber and in which unvaporized water collects,

an electric heating means within said chamber for heating said heat accumulating bodies,

said electric heating means including an element extending into said trough for vaporizing water accumulating therein,

a conduit for conducting water to said nozzle,

a valve for controlling the flow of water through said conduit,

temperature controlled means for effecting actuation of said valve in response to the temperature of said trough, so that said valve is closed when the trough temperature is below a predetermined value and opened when the trough temperature is above said predetermined value, such as when there is no water in said trough, and,

a source of electrical energy.

2. An electric sauna unit as claimed in claim 1, in which said valve is solenoid controlled, and a bimetallic switch in the line leading to said solenoid periodically operating to open and close said valve.