SK92394A3 - Switching device for instantaneous water heater - Google Patents

Abstract

Described is a switching device (1) for instantaneous water heaters, which switches the water-heating device (2) on and off as a function of water throughput. The switching device has a cylindrical switch element (11, 11'; 111, 111'), made for instance of metal, movably mounted in a vertical section of the flow line (10, 10'; 141, 141'), the switch element being moved, at a given water flow rate, by the water flowing through, from a lower (rest) position to an upper (switching) position. The switching device also has a position sensor (16, 16') which detects the change in position of the moving switch element (11, 11'; 111, 111'), the position sensor preferably taking the form of a light-barrier switch with a light source (17; 147, 147') and a photo-detector (18; 146, 146') and which is connected to a switch (19) controlling the heating device (2).

Description

BACKGROUND OF THE INVENTION The present invention relates to a switching device for a instantaneous water heater having a flow-through sensor installed in an overflow water conduit to which a switching unit is connected, a heating device adapted to heat water, the sensor device comprising a switching body disposed movably flow of water both before and after the heating device in one section of the flow line, which is movable by the flowing water at a predetermined flow from the rest position to the switching position _T 8 from the position sensor detecting the position change of the movable switching body connected to the switching heating unit.

PS ^ erajší_stav_techniky

In practice, they are currently commonly used; instantaneous water heaters whose switching device monitors and utilizes the pressure drop in the water flow pipe caused by the opening of the tap water tap / to activate the switch or, in general, the switching unit of the water heater. For this purpose, there is provided a diaphragm, for example made of rubber or even a metal sheet, on which a tappet is placed, which switches, for example, a microswitch, the control current circuit or the pairs of contacts in the power current circuit. The diaphragm is loaded with static pressure on both sides by the return line in the rest position (with the discharge valve closed). In this idle position: the switching unit is in a position in which it is inactive for the heating device, so that the heating device ⁷ is not in operation. When the discharge valve is opened, the static pressure on one side of the diaphragm drops and a pressure difference occurs on the diaphragm so that the diaphragm is deflected and the tappet attached to it is displaced. This will cause the desired switch-on.

Such control of the diaphragm is advantageous to the extent that a relatively high mechanical force is available for switching, so that several pairs of contacts can be switched on, but the disadvantage of this solution is that the diaphragm arrangement is expensive because the diaphragm must have. of considerable magnitude and therefore the pressures exerted on it must be absorbed in the body in which it is placed. It is also problematic to seal and clamp the diaphragm in this body, and there is also the disadvantage that the diaphragm is constantly in contact with water, the direct contact of the liquid to be heated with the mechanical components causing corrosion, premature aging and the like. In addition, the permanently elastic deflection movements cause fatigue of the material, so that the membrane has a limited life. Switching devices of this kind are therefore disadvantageous from the point of view of design, manufacture and assembly, due to the many components precisely manufactured.

Similarly, in terms of their function, known switching devices have different disadvantages because they are switched depending on the difference! pressure, the difference in pressure used for switching occurs only above a certain minimum pressure. The water pressure in the network is different in different places, so there is already a danger that the switch-on does not always take place properly. In particular, there is a danger that the pressure difference sufficient to switch on occurs only when the flow rates are only relatively small than at the high network pressure, so that: overheating - 8 ° until the formation of steam bubbles - while still no more water flows. Furthermore, the existing air bubbles are not recognizable by the pressure-responsive switching device, and when switched off, i.e. when the discharge valve is closed, hysteresis phenomena occur because the flow is constricted and yet there is a sufficient differential pressure across the membrane to the switch was further maintained. In this way it can also cause overheating »

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a switching device of this kind which is virtually pressure-independent in operation, does not cause overheating, such as the known switching device, and guarantees a high degree of switching reliability.

A further object of the invention is to provide a simple construction of a switching device which makes it easy to manufacture and install.

Podsteta_vynálezu

The instantaneous water heater switching device having a flow-through sensor associated with the overflow water line to which the switching unit of a heating device adapted for heating water is connected, the sensor-comprising device having a switching element arranged movably in the direction of water flow both upstream and downstream of the heating device in one section of the flow line which is movable by the flowing water at a predetermined flow from the rest position to the switching position and from a position sensor detecting the position change of the movable switching body connected to the switching unit of the heating device according to the invention, wherein each section of the overflow line with the switching body is a bypass line to the main line for water flow, consisting of a line section connected to the main lines by connecting lines, with both ends In both areas of this conduit section, the two positions of the switch body, namely the rest position and the switch position, are determined, and that both position sensors and the two movable switch bodies are arranged in a one-piece plastic block in which the overflow conduit sections .

This is achieved by making the switching dependent on the flow rather than on the difference

metal, which also achieves independence from the amount of network pressure. It is furthermore advantageous that instead of a resiliently deflectable mechanical component (membrane), a movable switch body is provided which causes the switch to be switched on, the switch body being easily protected on its surface or formed so that when it is arranged in the flow line, i.e. the water to be heated has a virtually unlimited service life without affecting its function. There is also significant that the position sensor, which is associated with the switch body can be arranged outside pretek8n.e ^x leadership, so then comes into contact with water. The position sensor is in the closing position, so long as there is no or only a small amount of water flowing through and the switching body virtually leaves its idling position, so that the switching unit is idle, i.e. the heating device is switched off. Upon reaching a predetermined flow rate, the switching body is carried by water far enough to its switching position, whereby the position sensor now responds to this change in position of the switching body so that the switching unit of the heating device is activated and the heating device is switched on. If, for example, by throttling the drain valve, the water flow decreases again, the switching body moves back from its switching position and, for example, even in the intermediate position, it affects the position sensor by opening the control current circuit again (activating the switching unit) so that the heating device turns on again.

The dimensions of the switch body and the flow line section in which the switch body is located are matched to the respective requirements, such as the heating capacity, the required switching flow rate and, where appropriate, the mean water temperature and other viscosity-affecting variables. required switching at the predetermined flow rate. In general, it can be provided that the flow cross section of the flow line section is only slightly larger than that of the switching body.

In addition to the functional advantages mentioned above, the construction according to the invention achieves a design improvement as well as an improvement in production and assembly in that only a simple movable switch body is provided in the flow line, thus avoiding problems. sealing as well as complicated assembly and manufacturing procedures.

Overall, therefore, the switching device according to the invention has a simple, robust construction with a long service life and, in addition to the known switching devices, also has an improved switching function.

In this case, it is possible to achieve a very substantial additional improvement or a considerably higher switching certainty by means of a particularly advantageous embodiment of the switching device according to the invention, characterized in that movable switching switches are always provided in the water flow section both upstream and downstream. body to which the respective position sensor is assigned. In this way, a particularly high degree of certainty is achieved when the heating device is switched on and off, namely when a predetermined flow reaches or falls below a predetermined flow rate, and also virtually no malfunction of the switching device can occur. periods warmer or cooler, wherein, with the water supply temperature, its viscosity _{r also} changes, and these viscosity changes could in certain circumstances lead to movement of the switching body at slightly changed flow values.

To the two position sensors to mohol.byť the above described preferred embodiment is connected as a logic circuit stabilizing medium flow rate, wherein the switching causes to fund any fluctuations also carried on the hot or cold ^1? · Portions of the flow conduit to the switching element. However, it has been shown that a simple design, while at the same time achieving a particularly high degree of operating reliability, is possible if the heating device is activated by the switching unit only when both position sensors detect a change in position of the movable switching body from idle to switching position. In this further embodiment according to the invention, therefore, the output signals of the two position sensors in the switching unit are combined with one another in the logic AND, and only when there are switching signals from both position sensors the switching unit activates the heating device. The same applies to the shutdown when the flow is swelling, for example by closing the water tap. Especially when switched off, this design has an increased reliability of operation, since possible too long heating of the water due to the occurrence of hysteresis phenomena is prevented.

As an additional safeguard against excessive water heating, a temperature sensor can be associated with a switching unit as a safety switch against overheating on several sections of the flow line downstream of the heating device for recording the temperature of the heated water. In this case, a simple design can be achieved in that this temperature sensor is formed by a temperature-dependent electrical resistance, preferably an NTC resistance, i.e. a resistance having a negative temperature coefficient.

That was not possible when the water flow is not affected, it turned out to be advantageous also to _r. when the section or each section of the flow line with the switching body is formed as a bypass line which is connected in parallel to the main water flow line. In this way, the water flow is split and only a part of the water flow, in parallel connection, is used for switching, in which way a particularly precise switching can be achieved. A particular advantage here is that the bypass line has only a smaller flow cross-section than the main line. In this way, the ratios in the main line and the ratios in the bypass line, i.e. the switching line, are virtually independent of one another.

To achieve for. unambiguously switching on the desired laminar flow without vortices, it is also advantageous if the bypass line from a straight line section connected to the main line through the connecting lines, in which both positions of the switching body 4, namely the resting position and the switching position, are determined. In this embodiment, a linear path of movement of the switching body is also produced, so that its precise switching movement is ensured, not affected by the impact on the side walls of the guide.

In order to achieve a robust, compact and small assembly unit, it is particularly advantageous if one or two position sensors, as well as one or two movable switching bodies, are arranged in a single block comprising the section (s) of the flow line and possibly main e connecting line. All essential components of the switching device are therefore arranged in this block. This block is made for production reasons as a one-piece, preferably acrylic glass (plexiglass). This material is both sufficiently impact and temperature resistant and also allows the use of: optical position sensors, as will be explained in more detail below.

For manufacturing reasons, it is also advantageous if the section or sections of the overflow conduit and, if appropriate, the main and connecting conduits are formed in the form of holes provided with connecting fittings or plugs on the surface of the block.

In this connection, it is advantageous to use as a heating device of an electric resistance heating device, even if, for example, a gas heating device can be switched on and off by means of the existing switching device. It is particularly advantageous if the resistance heating device is located directly inside the conduit flowing through the water to be heated. Such resistive heating device ² allows the hot water with high efficiency, thereby preventing overheating, which otherwise possibly occurred ,, and by said error-free switching of the switch device of the invention with sufficient certainty.

As mentioned above, an optical sensor is preferably used as the position sensor. it is also advantageous for the position sensor to be a light source and a photoelement arranged opposite to the light source, which together form a so-called light barrier. In this case, the path of the light beam from the light source to the photoelement has a path of movement of the switching switch. wherein the light beam or light barrier is interrupted by the movable switch body in its rest position, and that the light beam strikes the photoelement when the movable switch body has left its rest position and moved to its switch position. A light beam striking the photoelement then generates an electrical signal which is used in the switching unit to activate the switch-on, i.e. to switch on the heating device. Preferably, a phototransistor or photodiode is used as the photoelement. These construction elements are inexpensive and have a high functional reliability as well as a small construction size, so that they are easy to place in the required place.

Instead of an optical position sensor, however, any known otherwise known position sensor can also be used. It is particularly preferred that the position sensor or each position sensor is formed by an inductive switch, or that the position sensor or each position sensor is formed by a capacitive position switch. These inductive or capacitive position sensors are commonly available on the market and are advantageous when, for various reasons, it is not possible to use transparent material on the line walls, and in addition the position sensor can be placed outside the flow line section to position electronic components. out of reach of water.

Especially in the latter cases, i.e. when the position sensor is designed as an inductive or capacitive position sensor, it is advantageous if the movable switch body or movable switch bodies are made of metal. In addition, by virtue of this design, it is quite generally possible to achieve the advantage that the switching body can be manufactured in a very precise manner, so that the determination of the switching flow rate can also be carried out quite accurately. It is also important here that there is a relatively large difference between the specific masses of the switching body and the water, which facilitates the calculation of the dimensions of the switching body.

In order to achieve an accurate, calm and uniform switching, it is also advantageous if the switching body or each switching body is in the form of a rod and the respective section of the flow line is straight. In order to facilitate the adaptation of the cross-section of the switching body to the usual cross-section of the flow lines, it is further preferred that the switching body has the shape of a circular cylinder.

In the switching device according to the invention, the arrangement can be carried out in such a way that the switching movement of the switching body is carried out independently of the alignment, and a return device is provided for the switching body, in particular in the form of a traction spring, for example a coil spring or a rubber spring. Since this return device is an embodiment of additional components which can shorten the life of the switching device in general, the return of the switching body from the switching or operating position to the keyed position is preferably performed only by the weight. Therefore, it is particularly advantageous if the section or each section of the flow line comprising the movable switch body is designed as a straight line and arranged vertically. The switch body then has a lower rest position and an upper switch position from which, if little or no water is flowing, it falls down again under the influence of gravity; Here too, the metal body of the switchgear is advantageous, as already mentioned above.

To precisely determine the different positions of the switching body or each switching body, it has finally proved advantageous if the extreme rest position and the extreme switching position of the movable switching body or each movable switching body are defined by end stops.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which: FIG. 1 shows a schematic diagram of a basic embodiment of a switching device, FIG. 2 shows a similar schematic diagram of a switching device with a double switching function, FIG. 3 in an exploded configuration, a block with bolts and connection fittings for carrying out a dual function switching device in one switching block; FIG. 4 shows a plan view of such a switching block.

Fig. 5 is a front view of such a switching block, FIG. 6 is a vertical section on an enlarged scale. such a switching block along line VI-VI of FIG. 4, for showing both sections of a flow line comprising one switching body, FIG. 7 is also an enlarged horizontal cross-section of such a switching block along line VII-VII in FIG. 5, to show: the arrangement of the optical position sensors, FIG. 8 shows a front view of the switching block of FIG. 3 to 5 seen from the left in the direction of arrow VIII in FIG. 4, FIG. 9 is a front elevational view of this switching block in the direction of arrow IX in FIG. 4, FIG. 10 is a block diagram of a switching unit with thyristor control of a three-phase heating device.

? £ Íki2dy_prevedenia_vynálezu

In FIG. 1 shows a flow heater switching device 1, wherein the heating device 2, for example in the form of an electric resistance heater, is shown only schematically. This heating device 2 is located, for example, inside the vessel from which it traces the outlet pipe 4 to the discharge valve 4, i.e. the water tap of the valve, and from there leads to the outlet.

The switching device 1 consists of a switching block 7, made of a one-piece block 8, in which the sensing elements necessary for initiating the switching on and off of the heating device 2 are arranged, as will be described in more detail below. The block 8 is preferably designed as a one-piece block of plastic material, in particular of acrylic glass, but it can of course also be made of another material.

The block 8 is provided with holes, i.e. on the one hand, a main conduit 9 for water flow and, on the other hand, a parallel connection to this main conduit 9. forming a bypass conduit, representing a section 10 of the overflow conduit in which the switch body II is freely movable. The main line 9 and the flow line section 10 are connected to a cold water inlet, i.e. to a water supply line 13 by a so-called hole 12, and at the outlet side of the switching block 7 an outlet line 15 is connected to a common outlet opening 14 2 »

The switch body 11 in the overflow duct section 10, i.e. in the bypass duct, is generally designed as a metal bar-shaped bar body and may, for example, be provided with a plastic coating to ensure sufficient corrosion resistance. The switch body 11 is shown in FIG. 1 is shown in its lower rest position, while the dotted is shown in its upper switch position. The arrangement of the bypass line is here vertical, with the water flowing in the direction of the arrow inside the block 8 from the bottom up.

The switch body 11 is in its lower rest position when the discharge valve 5 is closed and the water is not flowing. When the drain valve 2 is opened, water flows through the supply line 13 to the switching block 7 and the switching block 2 proceeds to the outlet 2. The water flows inside the switching block 7, in particular: through the main line 9 upwards _r . wherein the proportional part of the water also flows up the bypass line and at reaching a predetermined flow, the water will be carried by the switch body 11 and lifted. When the discharge valve 2 is now only slightly open, little water flows through the main line 9e bypassing the underwater line and the switch body 11 is lifted: little, if any, but does not rise to its upper switch position; essentially remains in its rest position. The optical position sensor 16 in the form of a light barrier switch, consisting of a light bulb as a light source 17 and a phototransistor as a light-sensitive element, in short, photoelement 18, remains inactive because the switch body 11 does not interfere with the light beam anyway. in this situation, photoelement 18 / no control signal; so that the resistance heating device 2 is not connected to the el. network? and the water does not heat up. However, as has already been stated, however, this has been achieved immediately after a predetermined flow, the switching body moves. 11 by the effect of the flowing water in the section of the flow line or in the bypass line 10, the dotted surface in FIG. 1 / _r, whereby the light beam from the light source 17 now falls on the photoelement 18, on which it generates an electrical control signal, which occurs in the light source. the switching unit 19 shown in FIG. 1 only schematically is used to turn on the electric current for the resistance heating device 2 so that the water is heated. With the discharge valve 6 open, this switching position does not change, that is to say that the water is still heated.

If the water outlet 6 is again throttled, i.e. the drain valve

5, partially and later, completely closed, the metal switch body 11 drops below the set flow in the bypass line or the overflow line section 10 as a result of both the gravity and the downward travel so that it exits again into the light barrier, i.e. a light source 17 and a photoelement 18, so that the control signal emitted by the photoelement 18 is again interrupted; _; thereby, the switching unit 19 switches off the electric current to the heating device 2 and the heating device 2 no longer heats the water.

The directions of water flow are quite general in FIG. 1, as shown in FIG. 2 e 3 to 9 shown by arrow 1.

It should be noted that FIG. 1 is intended only to illustrate the general principle of dilution according to the invention, wherein the individual components e, in particular the switching block 7, are not drawn to scale but only schematically.

Next, FIG. 3 to 9 show the switching device 1 according to the invention in the present particularly advantageous embodiment, the principle of the dual switching function 1 having already been briefly described according to the principle diagram in FIG. 2, the view in FIG. 2 is also merely schematic and, in particular for ease of understanding, two switching blocks 7, 7 * with respective switching bodies 11, 11, are shown. which are freely movable - similar to FIG.

in the respective sections of the flow line, while in practice, as will be explained in accordance with FIG. 3 to 9, preferably provides a single common unit switching block 107 with both switching bodies 111, 111 '.

For the individual components of FIG. 2, which correspond to the same components in FIG. 1 ,. the same reference numerals shall be used, supplemented by an apostrophe.

Referring to FIG. 2 is not just in the cold water inlet before you-? a switching block 7 with a movable switch body 111 arranged in the flow line section 10 by means of a heating device 2, but in addition, a respective section is arranged in the outlet pipe 6 after the heating device 2. 10 of the flow line, also with the freely movable switch body 11. on the outlet side of which the water tap or the discharge valve 6 with the outlet 1 is then disposed. The position sensors shown in FIG. 2 only schematically assigned to the two switching bodies 11, 1Γ and which are also preferably optical position sensors, are connected with the respective signal lines 20, 21 to the switching unit 19 associated with the heating device 2. Further, it is in the region of the section 10, a temperature sensor 22 is provided, preferably in the form of a temperature-dependent resistance, namely an NTC resistor, i.e. a resistance with a negative temperature coefficient, which is also connected to the respective signal line 23 with the switching unit 19. These three the signal lines 20, 21 and 23 are logically associated with each other in the switching unit 19 such that the activation of the heating device / for this activation is schematically shown in FIG. 2, the switch 24 in the power supply 25 to the heating device 2 / is shown then and ib8 when the respective control signals occur on all three signal lines 20, 21 and 23, that is to say when the two switching bodies 11, 1Γ have been moved. from the idle position to the switch position, which means that the flow rate is greater than the predetermined smallest flow rate, and when the NTC resistance forming the temperature sensor 22 senses the temperature of the heated water below the upper limit value. Therefore, the logic connection of the three control signals in the signal lines 20, 21 and 23 in the logic AND is performed, schematically in FIG. Of course, this logical product can, of course, be achieved by any known, especially analogue switching technique, as is generally known to those skilled in the art.

In the embodiment of FIG. 3-9 adapted for only a single switching unit 7 _r which consists of a one-piece block 108 of acrylic glass, which are governed by different holes, which will be further described in more detail, and which form the various water the flow is leadership, as well as storage space for elements of position sensors. These holes are provided on the outside of the surface of the block 108 where different inlet and outlet pipes are connected, provided with screwed connection fittings 127 (for cold water supply). 128 / for the outlet duct 15 leading t to the heating device 2 in FIG. L and 2, which in FIG. 3 to 9, not shown (129) for the outlet pipe 4 extending from the heating device 2, but FIG. 1 and 2 (and 130) for the outlet pipe. 4 leading to the discharge valve 9 in FIGS. 1 and 2); otherwise, the holes to which no ducts are connected on the outside of the block 108 are provided with locking screws 131 to 138 »The connecting fittings 127 to 110 and the locking screws 131 to 138 are screwed into the respective holes, the seal being O-rings 139 «

In block 108 they are then on the cold side / as in block 7 in FIG. 2) provided two holes 140-141 of which one hole 140 forms the main conduit (as the main conduit 9 in FIG. 1) for the water flow, while the other hole 141 forms a section (corresponding to the section 10 in FIG. 1) of the flow line or by-pass line, respectively, as mentioned above, in which the movable switch body 111 is located (see in particular, FIG. 6 and 7 /. The hole 141 ' which forms the by-pass line is connected to the hole 140 forming the main conduit and further to the outlet hole 114 in which it is connected by means of the transverse connecting lines 142 ' screwed output connection fitting 128.

On the cold side of the block 108, mounting holes 144, 145 'are provided perpendicular to each other and perpendicular to the holes 140, 14X, the mounting hole 144 serving to receive the photodiode 146 (see also FIG. 6 and 7 / and the second hole 145 serves to accommodate the light source in the form of a bulb 147 / see. also FIG. 6 and 7, the light bulb 147 and the photodiode 146 are opposite to each other, having a bypass conduit 141 disposed therein, in which the switch body 111 is movably mounted, so that the photodiode 146 and the bulb 147 together form an optical position sensor for the photocell. The current and signal lines 148 and 149 are connected to these components of the position sensor, i.e. to the photodiode 146 and the lamp 147, as schematically shown in FIG. 7th

Similarly, they are on the hot side of block 108 (corresponding to FIG. 2 the elemental unit such as switching unit _T T_ portion 10 'and the switch body 11 *. shown behind the heater 2 /, provided holes 140, 14P to form a main conduit and a bypass conduit, or a section of overflow conduit in which the movable switch body X1 '* is housed.

The difference from the cold side here is only that the heating device 2 _r . which in FIG. 3 is not shown in detail, it is connected by connecting fittings 128, 129 to the upper side of the block 108, so that the hot water supply is provided not from below, as from the cold side, but from above from the heating device 2. a third vertical hole 150, which forms a feed line for the hole 14 '' forming the bypass line. The main flow of water is led from above through the connecting fitting 129 to each other by means of perpendicular, horizontal connecting holes 151, 152 to the hole 140 ~ * forming the main conduit, and from there to the lower connecting fitting 130. 6 and 7), which in FIG. 3 is not shown, raised correspondingly as the switching body 111 on the cold side of the switching block 107 when reaching a predetermined flow against the gravity effect, fed from above the connection fitting 129 through a hole 150 forming the supply line downwards and through another horizontal connecting hole 153 into the hole 141 * ♦ forming the bypass line from below in parallel connection, water honor.

Further, a lower horizontal alignment hole 154 is provided between the parallel, but countercurrent, holes 140 ', 141 * for connecting them, the alignment hole 154 having a reduced cross section against the other hole cross sections to cause water retention from the connecting hole 153 to be retained. , thereby causing the switch body 1111 to move in the hole 14Γ. representing the bypass line when the predetermined flow rate is reached, upwards.

To determine the end positions of the switching bodies 111, 111 *, on the one hand? In the lower rest position and in the upper uppermost switching position, the locking screws 131, 136 and 132, 135 respectively serve as stops, these locking screws 131,

136, 132, 135 of the screwed-in state extend into respective holes 141, 14Γ to a corresponding depth. Their stop function is not shown in detail in the figures, but results indirectly znáσ of the illustration, for example in FIG. 6, wherein the switch bodies 111, 111 'are shown in their respective lowest rest position, in alignment with respective transverse holes 142, 154, the respective bolts 131, 136 being axially aligned with the transverse holes 142, 154 and corresponding to their circumferences . The same applies to the upper stops in conjunction with the transverse holes 143. 152.

Finally, on the hot side, similarly to the cold side, the storage or mounting holes 144 ', 145' for receiving the photodiode 146 'and the lamp 147' are provided to form an optical position sensor on the hot side of the switching block 107. See also FIG. 3 shows, in particular, the representation of FIG. 6 and 7.

It should be noted that FIG. 4, 5, as well as 8 and 9, only block 108 without pins and bolts is shown, the figures only schematically indicating at the mouth of the holes the corresponding reference numerals in brackets indicating these connecting fitting and bolts respectively.

FIG. 3, 4 and 8, it is finally apparent that on the rear side of the bloktx 108 mounting holes 156, 157 and 158 are provided for fastening the switching block 107 to a structure (not shown).

The various connection fittings 127 to 130 and the lock screws 13i to 138 may be made of brass, for example.

For example, a temperature sensor 122 in the form of a resistance having a negative temperature coefficient lying on the front wall, for example, is embedded in the abbreviation 134 associated with the lower connection hole 153 on the left side. 6, wherein the temperature sensor 122 is connected by a line 123 corresponding to the signal line 23 in FIG. 2 connected to an electrical switching unit (as in FIG. 10), which is not closer to FIG. 3 to 9.

FIG. 10 is a block diagram for schematically illustrating an exemplary embodiment of a switching unit 19 to be used. switching on and off of heating system 2 _f as well as for output control. For example, it may be a three-phase system with three phases L1, L2, L3. One neutral conductor N as well as protective ground 160, whereby three electric heating resistors 161, 162, 163 are connected to the three phases L1, L2, L3. These three electric heating resistors 161, 162, 163 are connected by switches / corresponding to e.g. FIG. 2), formed by thyristors 164, 165, 166, associated with respective phases LL, LL, L3. The control electrodes of the three thyristors 164, 165, 166 are connected to the output of the zero crossing detector 167, which is connected with three inputs to the three phases L1, L2, L3, and then when the heater 2 is to be switched on! or switch off, the switching signal is transmitted to the control electrodes of the thyristors 164, 165 at the respective passage of the individual phases. In this way, no voltage jumps occur during operation or interference voltages are prevented.

The heating power or the power of the three-phase current in this embodiment is adjusted by the percentage of switching time of the thyristors 164, 165, 166, to which a power actuator 168 is provided, for example with a not adjustable step potentiometer. The supply of the output control or switching signals from both the position sensors (photodiodes 146, 146 ') and the temperature sensor 122 is shown in FIG. XO is shown schematically, with the respective control electronics 169, which can be converted in a variety of forms, to which the zero crossing detector 167 is connected.

In operation, a corresponding control signal is supplied to the zero crossing detector 167 only when both position sensors, i.e. both photodiodes 146, 146 *, have detected a change in the respective switching body 111 or 11V from idle to the upper switching position, i.e. when they receive light, and at the same time the NTC resistance forming the temperature sensor 122 detects a drop in the water temperature below a predetermined upper limit value. In this case, the control electronics 169 supply respective control pulses to the zero-crossing detector 167 which energize the thyristors 164, 165, 166, so that the load current is occasionally released by thyristors 164, 165 and 166. According to the setting of the power actuator 168. a clock pulse transmitter (not shown in more detail) adapted to the dilution electronics 169. In this case, the zero-crossing detector 167 causes the thyristors 164, 165, 166 to pass through the entire half wave.

As soon as only one of the switching bodies 111, 11Γ falls again down to its rest position, or as soon as the temperature sensor 122 detects a temperature rise beyond the predetermined limit value, thyristors 164 ,. 165, 166 are closed by the zero crossing detector 167, i.e. the heater 2 is switched off. This is done, for example, by throttling the flow rate by means of the fitting / exhaust valve 8 in FIG. 1 and 2 /.

Otherwise, the above explanations can be pointed out in terms of mode of operation.

In one practical case for the purpose of carrying out the tests, a 9 kW heater having a different diameter of the holes constituting the main conduit, the bypass conduits and the connecting conduits of 6.5 mm, and the diameter of the rod switches m, 11Γ, was provided. 6 mm. The length of the holes 140, 140 'forming the main conduit and the holes 141, 141 * forming the bypass conduits were approximately 34 mm and the length of the switch bodies

111, 11Γ was about 20 mm. The diameter of the alignment hole 154 was the same as the diameter of the mounting holes 145, 145 * for filament lamps 147, 147 *, and 3.3 mnr, while the diameter of the mounting holes 144, 144 * for photodiodes 146, 146 * was 5.5 mm. The thickness of the acrylic resin material remaining between the individual holes. 141 *, forming bypass lines, and mounting holes 144, 144 * 145, 145 * for photodiodes 146, 146 *, and bulbs 147, 147 * were approximately 2, respectively. 2.5 mm.

While the invention has been elucidated in more detail by way of particularly advantageous embodiments, it is, of course, possible to make other modifications and modifications within the scope of the invention. Thus, for example, inductive switches or capacitive positioners can be arranged in correspondingly provided holes, instead of the optical positioning leads tormented by photoiodes and light sources. It would also be possible in principle to separate the cold and hot side of the switching block 107, i.e. to form two separate blocks. 2, or it would also be possible to connect the hot side of the switching block downside to the heating device, that is to say that hot water from the heating device 2 would be supplied to the lower side of the switching block, like on the cold side. on the underside, and the pipe leading to the drain valve then connect to the top of the switch block. In this way, it would be possible to save a separate supply line formed by a hole 150. However, for the assembly reasons to form a compact densified construction of the switching block together with the heating device, the embodiment illustrated in FIG. 3 to 9.

Claims (8)

PATENT CLAIMS Switching device (1) for a instantaneous water heater with a device with a flow-through sensor associated with a flowing water line to which a switching unit (19) of a heater (2) adapted to heat water is connected, the sensor-comprising device comprising (11, 11 ', 111, 111') arranged movably in the direction of water flow both upstream and downstream of the heating device (2) in one section (10, 10 ', 141, 141') of the overflow line which is movable as a result of the flowing water at a predetermined flow from the idle position to the switch position, and a position sensor (16, 16 ') detecting the position change of the movable switch body (11, 11', 111, 111 ') connected to the switch unit 19) of a heating device (2), characterized in that each section (10, 10 ', 141, 141') of the overflow line with the switching body (11, 11 ', 111, 111') is a bypass line to the main line (9). , 140, 140 '/ diam e a flow of water consisting of a conduit section connected by connecting conduits (142, 143, 152, 154) to the main conduit (140, 140 '), wherein both end positions of the switch body (111, 111') are defined in both end regions of this conduit section and that both position sensors (16, 16 ') and the two movable switch bodies (11, 11', 111, 111 ') are arranged in one piece. block (8, 108) of plastic, in which the sections (10, 10 ', 141, 14 pret) of the overflow line and the main and connecting lines (9, 140, 140', 142, 143-, 152, 154) are formed. Switching device according to claim 2, characterized in that each bypass line (10, 10 ', 141, 141') as well as the main and connecting lines (9, 140, 140 ', 142, 143, 152, 154) are formed by holes provided on the surface of the block with connecting fitting (127, 128, 129, 130) or by closing abbreviations (131 to 138). Switching device according to claim 1 or 2, characterized in that each bypass line (10) has a smaller flow cross-section than the main line (9). Switching device according to one of Claims 1 to 3, characterized in that the block (8, 108) is made of transparent plastic and each position sensor is formed by a switch sc with a light barrier with a light source (17, 147, 147 ') and photoelement / 18, 146, 146 '/, facing this light source / 17, 147, 147' / * Switching device according to claim 4, characterized in that the block (8, 108) is made of acrylic glass. Switching device according to claim 3 or 4, characterized in that the photoelement (18) is a phototransistor. Switching device according to claim 4 or 5, characterized in that the photoelement (146, 146 ') is a photodiode. Switching device according to one of Claims 1 to 7, characterized in that each switching body (11). 11 ', 111', 111 '/ has the shape of a cylinder and the respective bypass line (10, 10', 141, 141 ') is straight.