HK1171067B - Switch of a gas valve unit - Google Patents

Description

Switching of gas valve units

The invention relates to a gas valve unit for regulating a gas volume flow supplied to a gas burner of a gas appliance, in particular a gas cooking appliance, wherein the gas valve unit has a gas inlet, at least two open/close valves, at least two throttle points and a gas outlet.

Gas valve units of the type described are described, for example, in publications EP 0818655 a2 and WO 2004063629 a 1. The gas valve unit allows the gas volume flow to be controlled in a plurality of stages to a gas burner of a gas appliance. The gas volume flow here has a reproducible magnitude at any stage. The effective throughflow cross section of the gas valve unit is adjusted overall, and thus the size of the gas volume flow, in that certain opening/closing valves of the gas valve unit are opened or closed, so that the gas flow through certain throttle openings is opened or interrupted.

The gas valve units known from EP 0818655 a2 and WO 2004063629 a1 branch out after the gas inlet a plurality of parallel branch gas lines, which each have an open-close valve and a throttle point. All branch gas lines lead into a common gas outlet. In another embodiment of EP 0818655 a2, a plurality of throttle points are connected in series and are each provided with a bypass line. An open/close valve is additionally provided on each bypass line. Known embodiments are used to adjust the throughflow cross section of the entire gas valve unit in a plurality of stages in such a way that the open-close valves each open and close independently of one another. Switching processes are specified in which one open/close valve must be open, while at the same time exactly the other open/close valve is closed. In practice, this switching operation leads to a reduction or increase in the gas volume flow to an undesirable value in a short time, so that the flame at the gas burner is reduced or increased in a short time.

The object of the invention is to provide a gas valve unit of the type mentioned in the introduction with improved switching properties.

According to the invention, this object is achieved in that: the gas valve unit includes a throttle section on which a plurality of throttles are serially disposed, the throttle section having a connection portion between two adjacent throttle points, respectively; at least two open-close valves are connected to the gas inlet at the inlet end and at least one open-close valve opens at the outlet end into a connecting section of the throttle section. The throttle section comprises a plurality of throttle points, which are connected in series and to one another with the connecting part. An open-close valve opens into each connection, which is connected at the input to the output of the gas valve unit. Opening the opening/closing valve allows bypassing all throttle points, which are located upstream of the connection in the series of throttle points, to which the opening/closing valve opens. The gas flow then only passes through the throttle points arranged downstream of the connection on the way to the gas outlet of the gas valve unit, and the open/close valves open into these throttle points. When the gas volume flow is set, the throttle points are bypassed in turn in such a way that at least one open/close valve is always open. It is not necessary here to simultaneously open one open-close valve and close the other open-close valve. This makes it possible to reliably avoid undesirable switching transients in the gas volume flow.

Preferably, the throttle section has a plurality of preferably at least four throttle points, each throttle section has a connection between two adjacent throttle points, and an open/close valve opens into each connection. The number of throttle points and open-close valves is exactly equal to the number of switching stages for the gas volume flow to the gas burner. The more open-close valves and throttle points are provided, the more finely the gas volume flow and thus the combustion output of the gas burner can be adjusted.

Furthermore, the throttle section-viewed in the gas flow direction-has an inlet section upstream of the first throttle point, and an open-close valve is connected at the inlet end to the gas inlet and opens at the outlet end into the inlet section of the throttle section. The pipe section of the throttle section preceding the first throttle point is referred to as the inlet section. In addition to the connection, the inlet part can also be connected to the gas inlet of the gas valve unit via exactly one open/close valve. The open-close-valve forms the only connection of the inlet section to the gas inlet.

Advantageously, the throttle point-viewed in the gas flow direction-has an increased flow cross section. The first throttle point with the smallest flow cross section defines the minimum combustion power of the gas burner. When only the first open-close valve, which opens onto the inlet section of the throttle section, is opened, the gas burner is operated at this minimum combustion power. The gas flow then also flows through all other throttle points of the throttle section on the way to the gas outlet of the gas valve unit. These further throttle points have a larger flow cross section and only a smaller flow resistance for the smaller minimum gas flow defined by the first throttle point. The second open/close valve is now opened, thereby bypassing the first throttle point, so that the second throttle point now defines a flow cross section which is decisive for regulating the gas volume flow. Since the second throttle point has a larger flow cross section than the first throttle point, the gas volume flow is also set to a larger value. Similarly, when the third open-close valve is opened, the first and second throttle points are bypassed. The effective flow cross section of the other throttle points left on the way to the outlet is then decisive for the gas volume flow. This operation is likewise continued for the other throttle points with their open/close valves.

Each throttle point is formed by at least one single throttle element, which is preferably a throttle orifice with a defined flow cross section.

It is particularly advantageous if each throttle point is formed by exactly two individual throttle elements arranged one behind the other. The two throttle elements together form a throttle point and have preferably the same flow cross section. In order to achieve a comparable throttling effect, two single throttle elements arranged one behind the other can each have a larger cross section than a throttle point with only one single throttle element. Practice has shown that particularly small chokes are difficult to manufacture. For this reason, according to an embodiment which is easy to manufacture, each throttle point is formed by two individual throttle elements.

The gas valve unit is designed such that the gas volume flow through the gas valve unit is equal to zero when all open-close valves are closed. The gas valve unit is thus also suitable for completely interrupting the gas feed to the gas burner.

When only the first open-close valve, which opens onto the inlet section of the throttle section, is opened, the gas volume flow through the gas valve unit is set to a minimum value, with the gas burners associated with the gas valve unit being operated at minimum power. As described above, with such an adjustment of the open/close valve, all throttle points of the throttle section are flowed through sequentially by the gas volume flow.

When at least the last open-close valve on the last connection, viewed in the gas flow direction, opening into the throttle section is opened, the gas volume flow through the gas valve unit is set to a maximum value, at which the gas burner corresponding to the gas valve unit is operated at maximum power. The gas volume flow then flows only through the last throttle point of the throttle section on the path of the gas valve unit from the gas inlet to the gas outlet. The last throttle point has a flow cross section such that the gas volume flow is not throttled or is throttled only slightly.

If at least one open-close valve opening onto an intermediate connection arranged between the inlet section and the last connection is open and at least one open-close valve opening onto a connection downstream of the intermediate connection is closed, the gas volume flow through the gas valve unit is adjusted to an intermediate value, in which case the gas burners associated with the gas valve unit are operated at a power between a minimum power and a maximum power. When opening the plurality of open-close valves, the gas volume flow is determined by the most downstream throttle point directly connected to the gas inlet of the gas valve unit and by the downstream subsequent throttle point. The other throttle points upstream in the flow direction of the throttle point located furthest downstream, which are likewise connected directly to the gas inlet, do not contribute to the gas volume flow at the gas outlet of the gas valve unit.

It is particularly advantageous to provide an actuating device for the open/close valves, which is designed such that either all open/close valves are closed, or exactly one open/close valve is open, or exactly two open/close valves are open, which are connected to two adjacent connecting sections or to the inlet section and to the adjacent connecting section. These open-close valves are switched substantially one after the other when the gas valve unit is actuated. In each switching stage, in the normal case exactly one open-close valve is open and the other open-close valves are closed, it being ensured that during the switching from one switching position of the gas valve unit to the next, not all open-close valves are closed at any time. Alternatively, the switching process is designed such that in the intermediate position between the two switching positions, there are always two adjacent open-close valves open. In this intermediate position, the gas volume flow is exactly equal to the greater gas volume flow of the two adjacent switch positions.

According to a particularly advantageous embodiment of the invention, the opening/closing valve can be actuated by means of a permanent magnet. The magnetic force of the permanent magnet is used here to open or close the open-close valve.

For this purpose, each open-close valve has a movable blocking body which, when the open-close valve is closed, rests against the valve seat and thereby closes the valve opening in the valve seat.

A spring is provided which presses the blocking body against the valve seat when the open-close valve is closed. When the open-close valve is opened, the force of the permanent magnet can be used to disengage the blocking body from the valve seat. In this way, a closing force of each open-close valve is generated by the spring, which closes the open-close valve independently of the installation position of the gas valve unit. The force of the permanent magnet can make the blocking body overcome the spring force and separate from the valve seat. When the open-close valve is actuated, the position of the permanent magnet relative to the blocking body of the open-close valve can be changed. In order to switch the gas valve unit, the permanent magnet is moved past the blocking body of the open-close valve. The blocking body, which is located directly adjacent to the permanent magnet, is attracted by the permanent magnet, thereby causing the open-close-valve to open. The open-close valve is then opened until the permanent magnet is moved away again from the area of the blocking body.

According to a special design of the invention-from the closed position, in which all open-close-valves are closed-the last open-close-valve on the last connection-seen in the gas flow direction-opening into the throttling section is first opened when opening the gas valve unit. This means that when the gas valve unit is actuated, it can be opened completely immediately, and the gas flow can then be throttled stepwise. The advantage of the gas valve unit being completely opened immediately is that the lines and the gas burner after the gas valve unit are filled with gas quickly. Furthermore, after opening the gas valve unit, the gas burner which is switched on immediately after the gas flow has been maximized can be ignited.

Further advantages and details of the invention will be described in more detail with the aid of the embodiments shown in the schematic drawings. The figures show that:

fig. 1 shows a schematic switching arrangement of a gas valve unit, in which a first open-close valve is open;

fig. 2 shows a schematic switch arrangement in which two open-close-valves are open;

fig. 3 shows a schematic switch arrangement in which the last open-close-valve is open;

fig. 4 shows a schematic structure of the air valve device in which the open-close-valve is closed;

FIG. 5 shows a schematic configuration in which there is one open-close-valve open;

fig. 6 shows a schematic configuration in which the first two open-close-valves are open;

FIG. 7 shows a schematic configuration in which there is one open-close-valve open;

fig. 8 shows a schematic configuration in which the last open-close-valve is open;

fig. 9 shows a schematic structure of a modification of the gas valve unit;

fig. 10 is a perspective view of the air valve unit viewed from obliquely above;

fig. 11 is a perspective view of an open-close-valve;

fig. 12 is a perspective view of the air valve unit viewed obliquely from below;

FIG. 13 is a perspective view of the lower gas distribution plate;

fig. 14 is an exploded view of the air valve unit viewed obliquely from below;

fig. 15 shows a variant of the switch arrangement according to fig. 1 to 3 in the fully closed state;

fig. 16 shows a variant of the switch arrangement in the fully open state, in which one open-close-valve is open;

fig. 17 shows a variant of the switch arrangement in the fully open state, in which two open-close-valves are open;

fig. 18 shows a variant of the switch arrangement in a partially open state;

fig. 19 shows a variant of the switch arrangement in the minimally open state.

Fig. 1 shows a switch arrangement of a gas valve unit of the present invention. A gas inlet 1 is visible, through which the gas valve unit is connected, for example, to the main gas line of the gas cooking appliance. At the gas inlet 1 there is gas for combustion, which is at a constant pressure, for example 20 mbar or 50 mbar. A gas line, for example, leading to a gas burner of a gas cooking appliance, is connected to the gas outlet 2. The gas inlet 1 is connected via the gas inlet chamber 9 of the gas valve unit to the inputs of the five open-close valves 3 (3.1 to 3.5) in the present exemplary embodiment. By opening the open/close valve 3, the gas inlet 1 is connected in each case to a part of the throttle section 5 into which gas flows via the open/close valve 3. The throttle section 5 comprises an inlet section 7 into which the first open/close valve 3.1 opens. The other open-close valves 3.2 to 3.5 open into a connecting section 6 (6.1 to 6.4) of the throttle section 5. The transition between the inlet portion 7 and the first connection portion 6.1 and the transition between two adjacent ones of the connection portions 6.1 to 6.4 are both formed by the throttle points 4 (4.1 to 4.5). The last throttle point 4.5 connects the last connecting part 6.4 to the gas outlet 2. The throttle points 4.1 to 4.5 have successively larger opening cross sections. The flow cross section of the last throttle point 4.5 can be dimensioned such that the last throttle point 4.5 has practically no throttle function.

The open-close valves 3 are actuated by means of permanent magnets 8, which are movable along the row of open-close valves 3. The force for opening the respective open-close valve 3 is formed here directly by the magnetic force of the permanent magnet 8. This magnetic force opens the corresponding open-close valve 3 against the elastic force.

In the switching position according to fig. 1, only the first on/off valve 3.1 is open. Via this open-close valve 3.1, the gas flows from the gas inlet chamber 9 into the inlet section 7 and from there on its way to the gas outlet 2 through the entire throttle point 4 and the entire connecting section 6. The gas flow through the valve unit determines the minimum power of the gas burner connected to the valve unit.

Fig. 2 shows a schematic switch arrangement in which the permanent magnet 8 is moved appropriately to the right in the drawing, so that both the first open-close valve 3.1 and the second open-close valve 3.2 are open.

Via the open second open/close valve 3.2, the gas flows directly from the gas inlet chamber 9 into the first connecting section 6.1 and from there along the throttle points 4.2 to 4.5 to the gas outlet 2. The gas flowing to the gas outlet 2 bypasses the first throttle point 4.1 as a result of the opening of the open/close valve 3.2. The gas volume flow in the switching position according to fig. 2 is therefore greater than the gas volume flow in the switching position according to fig. 1. In fact, gas flows only via the second open-close valve 3.2 to the first connection portion 6.1. Since the open-close valves 3.1 and 3.2 remain open, the same pressure level is generated in the inlet section 7 as in the first connecting section 6.1. No further gas therefore flows from the inlet section 7 via the first throttle point 4.1 into the first connection section 6.1. Thus, if the permanent magnet 8 is moved further to the right in the drawing and thus the first open-close valve 3.1 is closed with the second open-close valve 3.2 open, the overall gas volume flow through the gas valve unit is virtually unchanged.

The permanent magnet 8 is moved to the right in the drawing, whereby the open-close valves 3.2 to 3.5 are successively opened, thereby gradually increasing the gas volume flow through the gas valve unit.

Fig. 3 schematically shows the switching arrangement of the gas valve unit, which is in the maximum switching position. The permanent magnet 8 is here in its end position on the right side of the drawing. The gas flows here directly from the gas inlet chamber 9 into the last connecting section 6.4 and on its way to the gas outlet 2 only passes through the last throttle point 4.5. The last throttle point 4.5 can have a large flow cross section, so that in practice no throttling of the gas flow takes place, so that the gas can flow through the gas valve unit virtually without throttling.

Fig. 4 to 8 schematically show the structure of the gas valve unit in terms of configuration, and the switching arrangement thereof is as shown in fig. 1 to 3. A valve body 20 is visible, in which the gas inlet 1 of the gas valve unit protrudes. Inside the valve body 20 there is a gas inlet chamber 9 connected to the gas inlet 1. The blocking body 10 of the open-close valve 3 is guided in the valve body 20 such that it can move up and down in the drawing. Each blocking body 10 is pre-stressed downwards in the drawing by means of a spring 11. Each blocking body 10 can be moved upwards in the figure against the force of the spring 11 by means of the force of the permanent magnet 8. The spring 11 presses the blocking body against the valve sealing plate 12, so that the blocking body 10 closes the opening 12a in the valve sealing plate 12 in an air-tight manner. A pressure plate 13 is provided under the valve sealing plate 12, and an opening 13a of the pressure plate corresponds to the opening 12a of the valve sealing plate 12. The openings 13a in the pressure plate 13 open into the openings 14a in the first gas distribution plate 14. In the figure, below the first gas distribution plate 14 there is a throttle plate 15 with a plurality of throttle orifices 18. Each throttle point 4.1 to 4.4 is formed here by two throttle openings 18. The two throttle openings 18 belonging to one throttle point 4.1 to 4.4 are connected to each other via an opening 16a in the second gas distributor plate 16. While the openings 14a of the first gas distributor plate connect the two adjacent chokes 18 of the chokes 4.1 to 4.4 arranged side by side. The last throttle point 4.5 is formed by only one throttle opening 18, which opens into the gas outlet 2 of the gas valve unit via a corresponding opening 16a in the second gas distributor plate 16.

In the switching position according to fig. 4, the permanent magnet 8 is in the end position, in which all open-close valves 3 are closed. The gas valve unit is thus closed as a whole. The gas volume flow is equal to zero.

Fig. 5 shows a schematic structure of the gas valve unit, in which the first open-close valve 3.1 is open. Gas flows from the gas inlet 1 into the gas inlet chamber 9 and from there flows via the valve sealing plate 12, the pressure plate 13 and the first opening of the first gas distribution plate 14 to the throttle plate 15. On the way to the gas outlet 2, the gas flows through all the chokes 18 of the choke plate 15 and all the openings 14a of the first gas distribution plate 14 and all the openings 16a of the second gas distribution plate 16.

Fig. 6 shows a schematic configuration, in which the first open-close valve 3.1 is open and the second open-close valve 3.2 is open. Since the second open/close valve 3.2 is open, the throttle opening 18 of the first throttle point 4.1 is bypassed, so that the gas reaches the second throttle point 4.2 directly and flows through the further throttle points 4.3 to 4.5 on its way to the gas outlet 2. Since the first open/close valve 3.1 is open, the gas path through the first throttle point 4.1 opens. Since the pressure level is equal on both sides of the first throttle point 4.1, virtually no gas flows through the first throttle point 4.1.

Fig. 7 shows a schematic configuration in which the second open/close valve 3.2 is open. All remaining open-close valves 3.1 and 3.3 to 3.5 are closed. The gas volume flow through the gas valve unit is practically the same as the gas volume flow according to the valve positions of fig. 6.

The permanent magnet 8 and the components of the open-close valve 3 are coordinated with one another such that either exactly one open-close valve 3 or exactly two open-close valves 3 are open when the gas valve unit is open. During the switching from one open-close valve 3 to an adjacent open-close valve 3, two adjacent open-close valves 3 are always open for a short period of time. This ensures that the switchover does not result in a brief interruption of the gas supplied to the gas burner, which would result in a flashover or extinction of the gas flame. The adoption of the connection method also ensures that the phenomenon that the volume flow of the coal gas is temporarily increased in the switching process can not occur. Flashovers of the gas flame during the switching process are thus also reliably prevented.

Finally, fig. 8 shows a schematic representation of the gas valve unit, with only the last open-close valve 3.5 open. In this case, the gas flows virtually unimpeded from the gas inlet via the gas inlet chamber, the open on-off valve 3.5 and the last throttle opening 18 associated with it to the gas outlet.

Fig. 9 shows a schematic structure of a variant of the gas valve unit. In contrast to the design according to fig. 4 to 8, the gas outlet 2 here branches off directly from the first gas distribution plate 14. When the open-close valve 3.5 is open, gas flows without throttling via the gas inlet 1, the gas inlet chamber 9, the open-close valve 3.5, the last opening 12a in the valve sealing plate 12, the last opening 13a in the pressure plate 13 and the last opening 14a in the first gas distribution plate 14 to the gas outlet 2. The last throttle point 4.5 (see fig. 4 to 8) is not present in the variant according to fig. 9.

A perspective view of one embodiment of the gas valve unit from obliquely above is shown in fig. 10. A valve body 20 is visible, in which a switching shaft 21 of the valve unit is rotatably mounted. Coupled to the switching shaft 21 is a transmission 22 which transmits the rotational movement of the switching shaft 21 to the permanent magnet 8, so that the permanent magnet is guided on a circular path during the rotational movement of the switching shaft 21. The cover 27 forms a sliding surface of the permanent magnet 8 and creates a prescribed spacing between the permanent magnet 8 and the open-close valve 3. The gas outlet 2 and an actuating lever 23 for a not shown magnetic valve unit, which is arranged in the gas inlet 1, are also visible. The operating lever 23 is coupled to the switching shaft such that the operating lever 23 projects from the valve body 20 under the axial pressing action of the switching shaft. So that pressing the switching shaft 21 opens the magnetic valve unit. The bore 24 serves to fix the magnetic valve unit to the valve body.

Fig. 11 shows the view according to fig. 10, wherein the transmission piece 22, the permanent magnet 8, is omitted. Fig. 11 shows, in particular, the annularly arranged blocking body 10 of the open/close valve 3. Each blocking body 10 is provided with a spring 11 which presses the blocking body 10 downwards in the drawing. One of these springs 11 is exemplarily shown in fig. 11.

Fig. 12 is a perspective view of the air valve unit viewed obliquely from below. Here, in particular, a cover plate 17 is visible, which presses together the remaining plates not shown in the drawing, namely the valve sealing plate 12, the pressure plate 13, the first gas distributor plate 14, the throttle plate 15 and the second gas distributor plate 16. The force required for this purpose is generated by means of the screw 25.

Fig. 13 shows the view according to fig. 12 with the cover plate 17 removed. Here, a second gas distribution plate 16 with openings 16a can be seen. Through these openings 16a parts of the throttle screen 15 and the throttle openings 18 located thereon are visible. It can also be seen that every two chokes 18 are connected by an opening 16a of the second gas distribution plate 16.

The exploded view 14 shows the layered structure of the air valve unit. Here, a valve body 20 is visible, which has a guide bore 26 for the shut-off body 10, not shown in this view, of the on/off valve 3. The following plates are inserted into the valve body 20 in the following order: valve sealing plate 12, pressure plate 13, first gas distribution plate 14, throttle plate 15, second gas distribution plate 16 and cover plate 17. The bolts 25 press the plates 12, 13, 14, 15, 16, 17 supported on the valve body 20 together.

In the present embodiment, the plates 12, 13, 14, 15, 16, 17 are individually inserted into the valve body 20, respectively. However, it is also possible to pre-manufacture the plates 12, 13, 14, 15, 16, 17 in groups such that they can only be jointly inserted into the valve body 20 and removed again. Depending on the design, either only the throttle plate 15 has to be replaced or the entire group of plates 12, 13, 14, 15, 16, 17 has to be replaced in order to retrofit the gas valve unit with another gas type.

Fig. 15 shows a variant of the switch arrangement according to fig. 1 to 3. The arrangement of the throttle section 5 with the throttle points 4 (4.1 to 4.5) corresponds exactly to the arrangement according to fig. 1 to 3. The arrangement of the gas inlet chamber 9 and the open/close valve 3 (3.1 to 3.5) also corresponds to the exemplary embodiment according to fig. 1 to 3. In contrast to the exemplary embodiments according to fig. 1 to 3, the gas inlet 1 is located on the right side of the gas inlet chamber 9 in the drawing. However, the position of the gas inlet 1 relative to the gas inlet chamber 9 and the gas flow direction inside the gas inlet chamber 9 are not very important for the function of the gas valve unit. In the throttle section 5, the gas flows in a direction from left to right, similar to the arrangement according to fig. 1 to 3. The throttle point 4.1 on the left in the drawing is therefore referred to as the first throttle point. The throttle point 4.5 on the right in the drawing is referred to as the last throttle point. According to this nomenclature, the open-close valve 3.1 on the left in the drawing is referred to below, and in the exemplary embodiment according to fig. 1 to 3, as the first open-close valve, and the open-close valve 3.5 on the right in the drawing is referred to as the last open-close valve.

In the switching position shown in fig. 15, the permanent magnet 8 is located to the right of the last open-close valve 3.5. The permanent magnet 8 thus does not exert a magnetic force on the open-close valve 3, so that none of the open-close valves 3.1 to 3.5 is open. This causes the valve unit to be completely closed and the connection between the gas inlet 1 and the gas outlet 2 to be completely blocked.

To open the gas valve unit from this switching position, the permanent magnet 8 is moved to the left into the region of the last open-close valve 3.5.

This switch position is shown in fig. 16, when the gas valve unit is maximally open. In this case, the gas flows directly from the gas inlet 1 via the last open/close valve 3.5 and the last throttle point 4.5 which are open to the gas outlet 2. The last throttle point 4.5 can have a large opening cross section, so that the gas flow is virtually unthrottled. In this case, the gas flows through the gas valve unit virtually without hindrance.

Since the permanent magnet 8 is moved to the left in the drawing, the gas flow can now be throttled in stages by means of the gas valve unit. Fig. 17 shows the intermediate position of the permanent magnet 8, in which it opens the two open-close valves 3.4 and 3.5. However, the gas volume flow to the gas outlet 2 is practically the same here as the gas volume flow according to the switching position of fig. 16.

In the switching position according to fig. 18, the permanent magnet merely opens the open-close valve 3.4. On the way to the gas outlet 2, the gas flow passes through both the throttle point 4.4 and the throttle point 4.5. The opening cross section of the throttle point 4.4 is smaller than the opening cross section of the throttle point 4.5, so that the gas flow is slightly throttled.

Fig. 19 shows the gas valve unit in the minimum open position, in which only the open-close valve 3.1 is open. On the way to the gas outlet 2, the gas flows through all throttle points 4.1 to 4.5. The throttle point 4 has an increasing cross section, as seen in the gas flow direction, in the throttle section 5. The resulting gas volume flow is thus determined primarily by the throttle point 4.1 with the smallest opening cross section. The flow resistance, which also influences the gas volume flow, caused by the remaining throttle points 4.2 to 4.5 is taken into account in the design of the open cross section.

In the case of the switch arrangements according to fig. 15 to 19, the gas valve unit is in the maximum open position immediately when it is actuated from its closed position. This has the positive effect that the gas-conducting lines and the gas burners downstream of the gas valve unit are filled with gas particularly rapidly. Furthermore, the gas burner can be ignited immediately after opening the gas valve unit when the gas volume flow is at a maximum, whereby the ignition process is easily carried out.

List of reference numerals

1 gas inlet

2 gas outlet

3 (3.1 to 3.5) open-close valve

4 (4.1 to 4.5) throttle point

5 throttle section

6 (6.1 to 6.4) connecting part

7 inlet part

8 permanent magnet

9 gas input chamber

10 blocking body

11 spring

12 valve sealing plate

12a opening

13 pressing plate

13a opening

14 first gas distribution plate

14a opening

15 throttle plate

16 second gas distribution plate

16a opening

17 cover plate

18 orifice

20 valve body

21 switching shaft

22 drive element

23 operating lever

24 holes

25 bolt

26 guide hole

27 cover member

Claims (18)

1. Gas valve unit for regulating the gas volume flow to a gas burner of a gas appliance, wherein the gas valve unit has a gas inlet (1), at least two open-close valves (3), at least two throttle points (4) and a gas outlet (2), characterized in that the gas valve unit comprises a throttle section (5) on which the throttle points (4) are arranged in series, the throttle section having a connection (6) between two adjacent throttle points (4); at least two open-close valves (3) are connected at the input to the gas inlet (1), and at least one open-close valve (3) opens at the output to a connection (6) of the throttle section (5).

2. A gas valve unit as claimed in claim 1, characterized in that the throttle section (5) has a plurality of throttle points (4); the throttle segments (5) each have a connecting section (6) between two adjacent throttle points (4); an open-close valve (3) opens into each connecting section (6).

3. A gas valve unit as claimed in claim 1 or 2, characterized in that the throttle section (5), viewed in the gas flow direction, has an inlet portion (7) before the first throttle point (4.1); an open/close valve (3.1) is connected at the input end to the gas inlet (1) and opens at the output end into the inlet section (7) of the throttle section (5).

4. Gas valve unit according to claim 1, characterized in that the throttle point (4), viewed in the gas flow direction, has an increased flow cross-section.

5. An air valve unit as claimed in claim 1, characterized in that each throttle point (4) is formed by at least one single throttle element, which is a throttle orifice (18) with a defined flow cross section.

6. An air valve unit as claimed in claim 5, characterized in that each throttle point (4) consists of exactly two single throttle elements arranged one after the other.

7. A gas valve unit as claimed in claim 1, characterized in that the volumetric flow of gas through the gas valve unit is equal to zero when all open-close valves (3) are closed.

8. A gas valve unit as claimed in claim 3, characterized in that when only the first open-close valve (3.1) opening onto the inlet section (7) of the throttle section (5) is opened, the gas volume flow through the gas valve unit is regulated to a minimum value, at which the gas burners corresponding to the gas valve unit operate at minimum power.

9. A gas valve unit as claimed in claim 3, characterized in that the gas volume flow through the gas valve unit is regulated to a maximum value when at least the last open-close valve (3.5) on the last connection (6.4) leading to the throttle section (5) viewed in the gas flow direction is opened, when the gas burner corresponding to the gas valve unit is operated at maximum power.

10. Gas valve unit according to claim 9, characterized in that the gas volume flow through the gas valve unit is adjusted to an intermediate value if at least one open-close-valve (3.2, 3.3, 3.4) opening onto an intermediate connection (6.1, 6.2, 6.3) arranged between the inlet section (7) and the last connection (6.4) is open and at least an open-close-valve (3) opening onto a connection (6) downstream of the intermediate connection (6.1, 6.2, 6.3) is closed, when the gas burner corresponding to the gas valve unit is operated at a power between a minimum power and a maximum power.

11. Gas valve unit according to claim 3, characterized in that an actuating mechanism for the open-close valves (3) is provided, which actuating mechanism is designed such that either all open-close valves (3) are closed, or just one open-close valve (3) is open, or just two open-close valves (3) are open, which are connected to one another by two adjacent connecting sections (6), or by an inlet section (7) and an adjacent connecting section (6.1).

12. A gas valve unit as claimed in claim 1, characterized in that the open-close valve (3) is operated by means of a permanent magnet (8).

13. A gas valve unit as claimed in claim 1, characterized in that each open-close valve (3) has a movable blocking body (10) which, when the open-close valve (3) is closed, rests against a valve seat, thereby closing a valve opening (12 a) in the valve seat.

14. A gas valve unit as claimed in claim 13, characterized in that a spring (11) is provided which presses the blocking body (10) against the valve seat when the open-close valve (3) is closed; when the open-close valve (3) is opened, the blocking body (10) is disengaged from the valve seat by the force of the permanent magnet (8).

15. A gas valve unit as claimed in claim 14, characterized in that the position of the permanent magnet (8) relative to the blocking body (10) of the open-close valve (3) is changed when the open-close valve (3) is actuated.

16. Gas valve unit according to claim 9, characterized in that-from a closed position in which all open-close-valves (3) are closed-the last open-close-valve (3.5) opening into the throttling section (5) -seen in the gas flow direction-on the last connecting part (6.4) is opened first when opening the gas valve unit.

17. The gas valve unit as recited in claim 1 wherein the gas appliance is a gas cooking appliance.

18. A gas valve unit as claimed in claim 2, characterized in that the throttle section (5) has at least four throttle points (4).