GB2241053A

GB2241053A - Electrical continuous-flow water heater

Info

Publication number: GB2241053A
Application number: GB9102827A
Authority: GB
Inventors: Rolf Kurz
Original assignee: Forbach GmbH and Co KG
Current assignee: Forbach GmbH and Co KG
Priority date: 1990-02-10
Filing date: 1991-02-11
Publication date: 1991-08-21
Also published as: PT96695A; NO910502D0; GB9102827D0; EP0442085A1; NO910502L; DE4004169A1; DE9017849U1; JPH0755256A

Description

j A ELECTRICAL CONTINUOUSFLOW WATER HEATER This invention relates to an

electric continuous-flow heater with a heated channel body and with a power switch.

A continuous-flow heater is a self-contained water heater with a high heating capacity in which the water is heated while flowing through it. The increase in temperature during that time depends on the volume of water flowing through the heater and on the heating capacity. As the heating capacity of an apparatus is constant, a certain outlet temperature occurs according to the volume of flow and the supply temperature.

Certain types of apparatus are fitted externally with means of setting the volume of flow and thus the outlet temperature within a certain temperature region. The higher the heating capacity of an apparatus, the greater the volume of flow obtainable for a given outlet temperature. Continuous-flow heaters of this kind are used for the central hot-water supply of an entire dwelling or for tap points situated close together, such as a shower and a wash basin. In one well known type of hydraulically controlled continuous-flow heater the heating capacity is switched in accordance with the volume of water flowing through it. This is done with a differential-pressure switch actuated by the flowing water when the hot-water valve (tap fitting) is opened. A certain minimum flow is necessary ifthe system is to function satisfactorily.

The ontinuous-flow heaters are designed to ensure that if there is only a slight flow the heating capacity switched on willbe automatically confined to only part of the total capacity, the full heating capacity not being switched on until a greater quantity is flowing through. Wit.h continuous-flow heaters it is usual to 4 instal an additional switch as a power selector in order to shut off the higher heating capacity when necessary, e.g. when the shower is being used or the hands are being washed. The heating device in such continuous- flow heaters may consist, for example, of heating coils installed in the actual flow of water inside a pressure-proof heating block of non- conductive material, such as plastic or ceramic. The dispenser fitting (tap fitting) is separate from the continuous-flow heater and associated with the particular tapping point concerned (bath, wash basin, shower) and is connected to the continuous-flow heater by a tapping pipe.

The object of the invention is to provide a continuous-flow heater especially for supplying a single tapping point and which will prove simple in its technical construction and therefore economical to manufacture and will involve only the minimum of labour and expense when being installed and connected up.

The invention solves this problem by providing the continuous-flow heater with a water flow release fitting integrated in its housing, the said fitting and also the power switch for the heating being operable by means of a common actuating device.

A continuous-flow heater of this kind is characterised by the fact that there can be tapped through it either varying quantities of cold water, or warm or hot water in varying quantities and at varying temperatures. The operation of connecting this continuous-flow heater to a water tap or cold water supply pipe is extremely simple. This:_. heater can be guaranteed to function completely even when the water is flowing at the minimum pressure, so that it is also eminently suitable i 1 A for cistern operation in holiday cottages and gardens.

A further object of the invention is to provide an advantageous method of operating a continuous-flow heater of this kind.

The solution to this problem resides in the fact that the rotation of the actuating device out of its zero position first of all releases the flow of cold water through the channel body, further rotation of the said device in the same direction resulting in an increase in the quantity of water flowing through, the electric power switch and thus the heating being switched on when the maximum flow is reached, and then when the actuating device is rotated still further the quantity of water flowing through the heated channel body is once more continuously reduced.

This method of operation enables cold water to be used for washing hands or for rinsing while also enabling dishes to be washed either with moderately hot or with very hot water. As the continuous-flow heater is first of all rinsed out with cold water after its heating system has been switched off, the residual heat still given off by the said heating system is absorbed by the said water and removed, so that the small volume of water in the channel system of the heater cannot reach the critical temperature which causes furring.

The invention is illustrated by way of example in the drawings, in which:

Fig.1 is an overall view continuous-flow heater; Fig. lb is of a small-size a view of the interior of this 4 small-size continuous-flow heater with the components required for its operation, and Figs.3-5 illustrate various operating settings available for this small- size continuous-flow heater.

The small-size continous-flow heater shown in the drawing consists of a housing 10 accommodating all components required for its operation. This small-size continuous-flow heater includes a cold water connection or cold water feed socket 13, a swivel-mounted outlet 12 with a fine-spray shower head 12' and a rotatable selector or actuating device 11 with graduated adjustment sections 1 and 2. The graduated adjustment section 1 represents the cold water tapping zone and the graduated adjustment section 2 the warm or hot water tapping zone.

The components essential to the operation of the small-size continuousflow heater are a bent or coiled tubular water conduit 3, a tubular electrical heating element 4, a temperature limiting safety device 5 associated with the said tubular heating element 4, an electric power switch 6 with a cam disc 6' and an integrated water flow release fitting 7 which controls the flow of water through the heated conduit 3. The water flow release fitting 7 and the electric power switch 6 with the asssociated cam disc 6' for its operation are connected to the selector or actuating device 11 via coupling elements not shown in the drawing and are actuated solely by the said device 11.

The small-size continuous-flow heater described operates as follows:

If the actuating device 11 belonging to the water flow i- j release fitting 7 occupies the zero position (Fig.2), the contact 6'' of the power switch 6 is open and the tubular electric heating element 4 is disconnected. The supply of cold water to the tubular water conduit 3 is shut off. By rotating the actuating device 11 in the direction shown by the arrow (Fig. 2) into the zone of the graduated adjustment section 1, cold water is first of all enabled to flow, via the water flow release fitting 7, through the tubular water conduit 3, the rate of flow increasing with the extent to which the said actuating device 11 is rotated (Fig.3). The maximum flow of cold water is reduced after a rotation through an angle of about 900. At the same time the contact V' of the electric power switch for the tubular heating element 4 is closed via the cam disc 6e, which is coupled to the said actuating device 11 in a manner not shown in the drawing, and the heating element 4 is switched on. When the actuating device 11 occupies this position (Fig.4), the quantity of heat now given off by the said tubular electrical heating element 4 is absorbed by a comparatively great quantity of water flowing through. This water thus only undergoes moderate heating. By a further rotation of the actuating device 11 into the graduated adjustment section 2 the quantity of water flowing through the conduit 3 is continuously reduced. Since, however, the electrical heating capacity remains constanti this determines the temperature of the water at the swivel mounted outlet 12, 12', by regulating the quantity of water flowing through. The rotation range of the actuating device 11 is limited to 1800 (Fig.5). The rate of flow is thus reduced to such an extent that the water emerging from the swivel mounted outlet 12 has a temperature of about 50-550C. By adjusting the end stop for the actuating device 11 the maximum water outlet temperature could be correspondingly adapted to the different connected loads of the continuous-flow heater. Such an adjustment of the end stop should preferably be effected at the works.

If the hot water tapping process is to be terminated the actuating device 11 is turned anti-clockwise (turned back) into the zero position in order to stop the flow of water through the conduit 3. When the actuating device 11 passes the 900 position in this process (when the graduated section 2 assumes the position shown in Fig.4) the electric power switch 6 is first moved into the "off" position by its cam disc 6', as a result of the opening of the contact 6'', i.e. the tubular electric heating element 4 likewise is first of all disconnected from the power supply, while the flow of water through the tubular element 3 has nevertheless still not been shut off. The flow is then only stopped when the actuating device 11 reaches the zero position shown in Fig.2 (idle or initial position).

A particular advantage of this method of operation resides in the fact that each time hot water has been tapped off the electric power is first of all switched off but that for a short period up to the final arrival of the actuating device 11 in the zero position cold water can still flow through the tubular water conduit 3. Residual heat still being given off by the tubular element 4 is thus absorbed without any difficulty by the water flowing through and furring of the heated tube 3 is avoided.

For washing dishes, for example, the continuous-flow heater described consumes 1.Z litres of water per minute at 550C, the power consumed amounting to 0.06kWh. This continuous-flow heater involves no power losses when being made ready for use and no line 1- 1 i 1 il T.

A losses, as water is only heated when actually needed and the connecting line from the heated conduit 3 to the swivel-mounted outlet 12, 12' is comparatively short. The apparatus is also independent of the water pressure in the water supply pipe, as the pressure losses in the flow system are negligible.

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Claims

I. An electric continuous-flow heater comprising a channel body, an electric heating system for the said channel body, an electric power switch for said heating system, a cold water connection for the channel body, a water outlet! a flow control means contained in a housing of the water and an actuating means, the arrangement being such that both the flow control means and the power switch are operable by means of the actuating means.
2. A continuous-flow heater in accordance with Claim 1, wherein the actuating device includes a rotary selector knob provided with graduated adjustment sections for a cold water tapping process and a hot water tapping process.
3. A continuous-flow heater in accordance with Claim 1 or 2, wherein the actuating device is associated with the housing of the heater.
4. A continuous-flow heater as claimed in any one of Claims 1-3, wherein said actuating means includes a manually operable member movable, from an idle position, through a first range of movement, an intermediate position and a second range of movement, the arrangement, in use, being such that during movement of said actuating means from said idle position through said first range of movement to said intermediate position said flow control means is caused to increase the volume of flow of water through said channel body to said water outlet from zero to a maximum, and vice versa, that during movement of said actuating means from said intermediate position c- 1 through said second range of movement said flow control means is caused to reduce the said volume of flow from the maximum to a predetermined value, and vice versa. and that upon movement of said actuating means through said intermediate position from said first range to said second range. said power switch is caused to switch on said heating system, and vice versa.
5. A continuous-flow heater according to Claim 4, wherein said predetermined value is adjustable in manufacture
6. An electric continuous-flow water heater, substantially as described herein with reference to the accompanying drawings.
7. A process for operating a continuous-flow heater in accordance with any one of Claims 1-6, wherein the rotation of the actuating device out of its zero position first of all releases the flow of cold water through the channel body, further rotation of the said device in the same direction resulting in an increase in the quantity of water flowing through, the electric power switch and thus the heating being switched on when the maximum flow is reached. and then when the actuating device is rotated still further the quantity of water flowing through the heated channel body is once more continuously reduced.

Published 1991 at The Patent Office. State House. 66171 High Holborn. London WC1R41P. Further coplesmay be obtained from Sales Branch. Unit 6. Nine Mile Point Cwmfelinfach. Cross Keys. Newport. NPI 711Z. Printed by Multiplex techniques ltd, St Mary Cray. Kent.