GB2243925A

GB2243925A - Ventilation means for a sauna

Info

Publication number: GB2243925A
Application number: GB9103941A
Authority: GB
Inventors: Antti Kivimaa
Original assignee: SAUNATEC Ltd Oy
Current assignee: SAUNATEC Ltd Oy
Priority date: 1990-03-07
Filing date: 1991-02-26
Publication date: 1991-11-13
Also published as: GB9103941D0; FI901151A; FI90723B; FI901151A0; SE9100643L; DE4105099C2; FI90723C; DE4105099A1; SE503811C2; SE9100643D0

Abstract

An electrically heated sauna wherein the level of ventilation is controlled for the comfort of a bather, the ventilation means including an inlet 8 and an exhaust duct 8 fitted with means for effecting the ventilation e.g. a fan or blower, the ventilation being increased from its normal level when the sauna is in use and then returned to the normal level after use. The increase is effected if the temperature rises to a set level or once the heater 9 has been switched on for a certain time, and the reduction is effected when the temperature falls below a set level or once the heater 9 has been switched off for a set time thus allowing rapid warm up of the room upon switching on and adequate drying upon switching off. <IMAGE>

Description

An electric sauna heater This invention relates to an electric sauna heater comprising one or more electric resistors for generating heat in a space where the heater is positioned, i.e. in a sauna room, the sauna room comprising a fresh air inlet; an exhaust air opening; and means for effecting the ventilation of the sauna room, such as a blower fitted in connection with the fresh air inlet of the sauna room, an adjustable valve fitted in connection with the fresh air inlet of the sauna room, the exhaust air of the sauna room being removed through a duct system provided with an extractor for exhaust air, or an extractor fitted in connection with the exhaust air opening of the sauna room.

One of the most important factors affecting the bathing comfort is the quality and amount of the air to be breathed in the sauna room. Appropriate ventilation is of vital importance in maintaining adequate freshness and oxygen content of the sauna room air. According to the most recent studies it is to be recommended that fresh air is introduced into the sauna room at least 50 cm above the heater both when using mechanical ventilation and when the air is removed freely through a flue leading to the roof.

The exhaust air valve in turn should be positioned as far from the heater as possible and relatively low, e.g., under sauna benches. In this way, temperature differences between the upper and lower portion of the sauna room are reduced to a minimum.

Even though the significance of the ventilation of the sauna room has been recognized, there does not exist any practical equipment which would enable the ventilation to be carried out in an optimal way. The object of the present invention is thus to provide an electric sauna heater which offers a solution to this problem. The electric sauna heater of the invention is characterized in that it comprises means for controlling the means effecting the ventilation, said control means comprising time-controlled and/or temperature-controlled switching means which adjust the ventilation to a level required by the bathing a desired time after the starting of the heater or at a desired bathing temperature of the sauna room, and return the ventilation to a normal level a desired time after the heater has been turned off or at another temperature lower than the above-mentioned temperature.In other words, the ventilation or ventilation level of the sauna room is controlled by means associated with the heater, so that the different modes of operation of the heater and the resulting different conditions in the sauna room can be taken into account simply and efficiently.

Preferably, said means comprise a blower fitted in connection with the fresh air inlet of the sauna room, and means for controlling the blower. In cases where the exhaust air is removed from the sauna room through a duct system provided with an extractor, said means preferably comprise an adjustable valve fitted in connection with the fresh air inlet of the sauna room, and means for controlling the valve. It is also possible that said means comprise an extractor fitted in connection with the exhaust air opening of the sauna room, and means for controlling the extractor.

In separate sauna rooms, a blower fitted in connection with the fresh air inlet is the simplest and most efficient alternative. In this way, efficient introduction of air into the sauna room is en sured, and possible leakage points of the sauna room do not affect the operation of the ventilation system. In apartment saunas, where the ventilation of the sauna room is connected with a ventilation duct system provided with a roof-installed extractor, efficient ventilation can be accomplished by the extractor by providing the fresh air inlet of the sauna room with a valve controlled by the sauna heater.In place of the blower fitted in the fresh air inlet, an extractor fitted in the exhaust air opening can be used, in which case, however, the construction of the sauna room has to be sufficiently air-tight in order that the air could be sucked from the desired point, that is, from the fresh air inlet.

On the other hand, it should be noted that the blowing creates a slight overpressure in the sauna room, which may result in the penetration of moisture into the structures of the sauna room.

The means for controlling the mechanical ventilation can be time-controlled switching means or temperature-controlled switching means or combinations thereof. When the switching means are controlled in this way, the ventilation can, for instance, be adjusted to a level suitable for bathing a desired time after the starting of the sauna heater and correspondingly returned to a normal level a desired time after the heater has been switched off, thus ensuring adequate drying of the sauna room.

Alternatively, the same operation can be achieved by means of temperature-controlled switching means which adjust the ventilation to a suitable level at a desired temperature, which may correspond to a low bathing temperature. However, the ventilation is not returned to a normal level until the temperature of the sauna room has dropped substantially below this bathing temperature. It is also possible that the ventilation is switched on in.response to temperature while the switching off is effected on a time-control basis.

In the following the electric sauna heater of the invention will be described in greater detail with reference to the attached drawings, where Figure 1 is a cross-sectional view of a sauna room; and Figure 2 shows an exemplifying circuit diagram for means comprised in the sauna heater for controlling the ventilation of the sauna room.

Figure 1 shows a cross-section of a sauna room in which the ventilation is realized in the most advantageous way in view of the present knowledge. In the figure, a fresh air inlet 6 is positioned at least about 50 cm above a sauna heater 9, and an exhaust air opening 10 is positioned at a maximum distance from the heater in the lower portion of the sauna room. In Figure 1, the fresh air inlet 6 is provided with an adjustable valve 7, and the exhaust air opening 10 communicates with a ventilation duct system 8 provided with air extraction means, such as a roof-installed extractor. As the fresh air inlet 6 is positioned sufficiently high above the sauna heater, the mixing of fresh air with the sauna room air in a space above sauna benches (not shown) is maximized while minimizing temperature differences between the upper and lower portions of the sauna room.The position of the 'exhaust air opening 10 in turn is as low as possible, in order that the air to be exhausted would be as cold as possible so as to minimize thermal losses caused by the exhaust air.

The sauna room shown in Figure 1 is further provided with an exhaust air valve 11 positioned in the upper portion of the sauna room. The purpose of the valve 11, which is normally closed during bathing, is to help to cool and dry the sauna room after bathing.

When using the electric sauna heater of the invention, however, this ventilation valve 11 is of considerably less importance than previously.

Figure 2 shows by way of example a circuit diagram for means comprised in the electric sauna heater 9 for controlling the ventilation of the sauna room in response to the mode of operation of the heater 9. The means shown in Figure 2 comprise an electric motor M for a blower or an extractor. The motor M is fitted either in connection with the fresh air inlet 6 so as to blow air into the sauna room or in connection with the exhaust air opening 10 so as to suck air from the sauna room. Said means further comprise relays 2 and 3 controlled by the heater for the control of the motor M.

In the arrangement shown, the motor M is provided with two coils so that it can be operated at two different powers. When the sauna room is not used for bathing, the motor M operates on a low power level, being supplied from a stage L of the electrical network through a switch 4, an overload protector 5, and a contact 3A of the relay 3. The contact 3A of the relay 3 is closed when the relay 3 is in rest state, as shown in Figure 2. In this way, appropriate ventilation of the sauna room between sauna baths can be realized by the motor M.

When the sauna heater 9 is connected in operation by closing a control switch 1, it is supplied with control current through a line K from the stage L of the electrical network through a control fuse S1, and at the same time the relay 2 is energized.

One pole of the control coil of this relay is con nected to a neutral wire N of the electrical network.

The relay 2 is a relay of delayed pick-up, so its contact 2A is closed a predetermined time after the closing of the switch 1. So the temperature of the sauna room has time to rise considerably, preferably relatively close to the desired bathing temperature, before the contact 2A of the relay 2 is closed, thus causing the relay 3 to be energized so that its contact 3B is closed and its contact 3A is opened.

Opening of the contact 3A means that power supply to the low-power coil of the motor M is disconnected, and closing of the contact 3B means that power is connected to the high-power coil of the motor M, so that the capacity of the motor M is increased.

When power supply to the sauna heater 9 is disconnected by opening the control switch 1, the relays 2 and 3 are also deenergized. The relay 3, however, is a relay of delayed drop-out, which means that its contact 3B opens a predetermined time after the control coil of the relay 3 has been deenergized. In this way, the blower keeps operating at its higher power some time after the sauna heater has been switched off. This time, e.g., about 2 hours, ensures efficient cooling and drying of the sauna room.

Figure 2 shows only one specific arrangement for the means comprised in the electric sauna heater for controlling the ventilation of the sauna room. In this example, the ventilation control means are timecontrolled. In place of these time-controlled relays, it is, of course, possible to use time-controlled switches, whereby their operating times too could be adjusted in a simple way. The time-controlled switching means could be replaced with temperaturecontrolled switching means which adjust the ventilation of the sauna room to a bathing level when the temperature of the sauna room approaches a desired bathing temperature but return it to normal at a temperature considerably below the bathing temperature. For example, the more efficient ventilation could be switched on at 60"C and returned to normal at about 30"C.

Naturally, it is possible to use a combination of time-controlled and temperature-controlled switching means. A viable arrangement would be to adjust the ventilation to the bathing level in response to the temperature of the sauna room and to return it to a normal level a desired time after the heater has been turned off.

As described above, the ventilation can be adjusted to bathing level, which means ventilation which is more efficient than conventional ventilation, i.e. the normal level, by increasing the power of the extractor or blower intended for the ventilation of the sauna room, or by widening the opening of the valve fitted in the fresh air inlet of the sauna room. In the latter case, it is necessary that the exhaust air opening of the sauna room communicates with a ventilation duct system provided with a roofinstalled extractor or other similar air extraction means. The exemplifying embodiments described above illustrate only one specific arrangement and it is to be understood that this arrangement can be modified considerably without deviating from the scope of protection defined in the attached claims.

Claims

Claims:

1. An electric sauna heater comprising one or more electric resistors for generating heat in a space where the heater is positioned, i.e. in a sauna room, the sauna room comprising a fresh air inlet (6); an exhaust air opening (10); and means for effecting the ventilation of the sauna room, such as a blower (M) fitted in connection with the fresh air inlet (6) of the sauna room, an adjustable valve (7) fitted in connection with the fresh air inlet (6) of the sauna room, the exhaust air of the sauna room being removed through a duct system (8) provided with an extractor for exhaust air, or an extractor (M) fitted in connection with the exhaust air opening (10) of the sauna room, c h a r a c t e r i z e d in that the sauna heater comprises means for controlling the means effecting the ventilation, said control means comprising time-controlled and/or temperaturecontrolled switching means (2, 3) which adjust the ventilation to a level required by the bathing a desired time after the starting of the heater (9) or at a desired bathing temperature of the sauna room, and return the ventilation to a normal level a desired time after the heater has been turned off or at another temperature lower than the above-mentioned temperature.

2. An electric sauna heater according to claim 1, c h a r a c t e r i z e d in that the timecontrolled switching means comprise a relay (2) of delayed pick-up for bringing the ventilation to the bathing level and a relay (3) of delayed drop-out for returning the ventilation to a normal level.

3. An electric sauna heater, substantially as herein described with reference to, and as shown in, the accompanying drawings.