EP2057416A1 - Gas regulating and safety valve for burners of a modulatable gas heating device - Google Patents

Abstract

The invention relates to an integrated gas regulating and safety valve for burners of a modulatable gas heating device. According to the invention, the gas regulating and safety valve comprises a housing (1) with two controllable closing elements, the axes of which are spaced apart from each other and extend one behind the other in series in the direction of gas flow between an inlet channel (2) and an outlet channel (4) of the housing. In the de-energized state, the two closing elements abruptly close the gas regulating and safety valve independently of each other, in each case by means of an associated spring element (7, 12). The first closing element, additionally serving for the modulation of the gas stream, has a drive spindle (15.1), which is formed as a spindle of a stepping motor (15), is surrounded by an excitation winding (16) and has placed on its end a restrictor component (8) and, at a distance from that, the first spring element (7). The second closing element, on the other hand, has a closure component (8) connected to an armature (9), wherein the armature (9) is arranged in a cylindrical cavity (18) and operates against the force of the second spring element (12) acting on the armature (9). This cavity (18) is surrounded by an excitation winding (17) of the armature (9) that is formed as part of an electromagnet.

Description

 Gas control and safety valve for burners of a modulable gas heater

The invention relates to an integrated gas control and safety valve for burners of a modulatable gas heater, which is used to adapt to a variable heat load and the abrupt shutdown of the fuel gas flow, especially when used for domestic heating and hot water supply gas boiler.

Generic gas control and safety valves have by default two electrically controllable actuator units, namely a quick-acting valve and a modulation valve. The two independently acting actuator units are actuated by means of electromagnets and closed in the de-energized state by return springs. The modulation valve is additionally sensitively adjusted by a proportional magnet or a stepping motor for the purpose of modulating the gas flow, so that two quick-action functions and a modulating function can be realized by means of two actuator units.

From DE 103 18 569 B3 a gas control and safety valve for burners of a modulated gas heater is previously known, which has two in a housing between an inlet channel and an outlet channel coaxially positioned closing elements. The first, outer closing element comprises a drive axle, a throttle body arranged at the lower end of the drive axle and a first pretensioned spring element acting on the first closing element, which is arranged in the upper region of the drive axle. The second, inner closing element arranged between the first spring element and the throttle body has a closure body connected to a hollow armature, which is designed to close one with the outlet channel connected annular gap is seated on a valve seat. The hollow armature is movable in a cylinder-like, surrounded by the drive winding of the hollow armature cavity and working against the force of a second prestressed spring element working.

In DE 101 14 175 C1 coaxial solenoid valve is described, wherein the magnetic drive comprises two axially superposed and each having a coil having independent magnetic circuits, which cooperate with two axially superposed anchors, one of which with the inner valve disc and the other with the outer valve plate is connected, wherein the armature of the outer valve plate is penetrated by a connecting the inner valve plate with its armature push rod.

In the invention disclosed in DE 198 26 076 C1 a double safety valve is described. In this case, the first (outer) valve disk in the direction of flow of the double safety valve surrounds the second (inner) valve disk, so that both valve seats are combined to form a common valve seat and this valve seat surrounds the single valve opening. In this double safety valve, a coil is further provided, which acts on a connected to the inner valve disc anchor. The outer valve disc engages behind the inner valve disc in the closing direction and is therefore taken along by the opening of the inner valve disc. A disadvantage of this invention is that the two valve disks are thus only opened together, and an independent operation of the two actuators is not given.

Furthermore, a double safety magnetic valve with two actuators is known from DE 195 25 384 C2 and from the almost identical EP 0 757 200 B1. The two actuators are arranged on a common axis, preferably one above the other, wherein the first actuator as a magnet armature has a hollow armature in which the armature of the second Actuator longitudinally projecting along the common axis and wherein only a single magnetic drive is provided for both actuators, in which the hollow armature and the armature protrude. Although a relatively compact construction is already achieved with this double safety valve, the axial height is high due to the axially displaceable as well as successively arranged valve plate or actuators.

In DE 103 61 918 A1 a gas-tight valve drive with motor and safety closing function is described, wherein the stepper motor used for the valve drive consists of a rotating rotor with integrated spindle nut system for converting the rotational into a translational movement and as a spindle with an actuating rod coupled to a valve cone. During a rotational movement of the rotor, the actuating rod slides along the motor axis in the hub by an integrated anti-rotation device in the valve body. To ensure the function of the safety adjustment, a return spring is provided. Characteristic of this invention is that the valve drive consists of a motor part and a valve member with a continuous actuator rod and formed as a helical spring return spring is placed on the drive side of the engine and as the first element of the valve member to the coupling element with the receiving valve body and the coupling element is coupled to the rotor of the motor part.

Particularly disadvantageous in the known gas valves is the fact that due to the many items required large tolerance chains or a superposition of the travel paths are recorded, on the one hand require a complex assembly and on the other increase the susceptibility.

Another significant disadvantage of the gas valves known from the prior art is that the sealing sleeve required to achieve the outer gas tightness limit the mechanical performance of the actuators of the gas valves. The object of the invention is now to propose a gas control and safety valve for burners a modulated gas heater, which is simpler to ensure two quick-closing functions and a Modulierfunktion, and in which the designated two closing elements are mechanically completely decoupled.

According to the invention, the gas regulating and safety valve for burners of a modulatable gas heater comprises at least one housing with two controllable closing elements whose axes are spaced apart and extend in a line in the gas flow direction one behind the other between an inlet channel and an outlet channel of the housing, wherein the first closing element in the direction of Inlet channel and the second closing element acts in the direction of the outlet channel. The two closing elements close in the de-energized state independently of each other by means of an associated spring element abruptly the gas control and safety valve. The first closing element serving in addition to the modulation of the gas flow comprises a throttle body and, spaced therefrom, the first spring element. The first closing element is driven by a spindle-nut system coupled to an electric motor with at least one exciter winding. The second closing element, however, has a closure body connected to an armature, wherein the armature is arranged to operate in a cylinder-like cavity and against the force of the second spring element acting on the armature. The cavity is surrounded by a trained as part of an electromagnet excitation winding of the armature.

The essential advantage of the invention over the prior art is that the two closing elements are completely mechanically decoupled from each other. In addition, waiving a gas-tight sealing sleeve in the air gap of the linear drive and / or Electromagnets larger actuating forces can be realized. By dispensing with the gas-tight insulating sleeve, the current-carrying components, in particular the excitation winding of the motor designed as a stepping motor of the first closing element and the field winding of the armature of the second closing element, placed in the gas stream. Practical tests have shown that the gas control and safety valve according to the invention can operate with up to 30% greater actuating forces, which leads to increased operational safety. This means that with the same force a more economical dimensioning of the gas control and safety valve according to the invention can be carried out.

In a particularly advantageous embodiment of the invention, the housing is formed in two parts with a first housing part and a second housing part, wherein the first closing element is placed in the first housing part and the second closing element in the second housing part. The housing preferably has a cylindrical shape, wherein the inlet channel and the inlet chamber are placed at a first end side and the outlet channel at the other end side. The two housing parts are usually connected to produce the gas control and safety valve in such a way that the frontal walls of the two housing parts lie on each other and seal against each other using a sealing element.

The anchor of the second closing element can be made both as a solid anchor and as a hollow anchor. A trained as a hollow anchor anchor is arranged working in the cylinder-like cavity against the force of the second spring element placed within the hollow armature. When using a full anchor, however, the second spring element attacks the outside of the solid anchor.

The spindle-nut system according to the invention can be arranged both within the electric motor and outside of the electric motor. in the In the first case, the nut or the rotor is driven by the field winding of the motor, wherein the spindle is designed as a drive axle. In the second case, the nut is driven by the motor shaft.

The spaced-apart axes of the two controllable closing elements can be placed anywhere in the housing, but preferably orthogonally as an angle valve, parallel or axially in a straight line one behind the other.

In the formation of the gas control and safety valve with axially in a straight line successively arranged closing elements, a corrugated spring plate is additionally provided for the purpose of balancing the axial tolerances and to ensure a required contact pressure of the two closing elements on the housing wall sandwiched between the facing end faces of the placed on both closing elements.

According to the conception of the invention, the inlet channel is arranged downstream of the inlet channel in the gas flow direction, wherein in the closed position of the gas regulating and safety valve the throttle body is gas-tight by means of its sealing surface on a valve seat arranged at the end of the inlet chamber and the closure body by means of its sealing surface on a valve seat arranged at the beginning of the outlet channel seated. The throttle body is in this case designed to be axially movable between an open position and a closed position in the inlet chamber.

The commonality of both closing elements is that both closing elements are each acted upon by an associated prestressed spring element. The significant difference in the function of both closing elements, however, is that the first closing element is a regulating function for adapting the gas flow to a variable heat load takes over and the second closing element is used exclusively as a safety shut-off device. The first closing element is moved by means of a linear drive from its closed position into its open position against a spring force. The second closing element, however, is held in its open position by means of an electromagnet.

Due to the independent function and operation of the two closing elements a complete blockage of the gas control and safety valve according to the invention in case of accident or failure is reliably excluded.

The throttle body of the first closing element may have any shape and valve characteristic for modulating the gas flow required to supply the burner of the gas heater. Preferably, however, a progressive valve characteristic is selected, as this variable supply pressures can be better stabilized and thus the risk of a swinging control loop is prevented.

The closure body of the second closing element then assumes the function of a safety shut-off device, when the gas control and safety valve is switched de-energized. In the event of power failure, the outlet channel is closed in a gas-tight manner by means of the closure body, in that the second spring element placed inside the hollow armature or the second spring element engaging externally in the case of a full armature relaxes.

In a preferred embodiment of the invention, the valve seat and the sealing surface of the throttle body are each annular, wherein formed in the open position of the throttle body between the valve seat and the throttle body, an annular gap for the incoming gas.

Another advantage of the invention is that the gas control and safety valve according to the invention is constructed of only a few components, which on the one hand increases the degree of prefabrication and on the other reduces the susceptibility to failure.

In the longitudinally extending gas control and safety valve, the gas flows substantially in the direction of the longitudinal axis of the housing without major directional deflections, so that in the open position of the gas control and safety valve or its closing elements, the pressure loss occurring is relatively low. For this purpose, a channel through which the gas flows is provided within the housing, which extends annularly from the inlet channel to the outlet channel around the two closing elements.

The significant advantages and features of the invention over the prior art are essentially:

■ by the spaced-apart arrangement of the axes of the two closing elements in a straight line one behind the other, the gas control and safety valve can realize waiving a sealing sleeve higher actuating forces and better efficiency,

■ the electronics can easily be integrated into the valve structure to control and regulate the valve, since the connecting line from the motor and electromagnet can be routed through a single gastight bushing placed in the housing wall of the valve,

^■ reduced manufacturing costs by using only a few components,

^■ the completely mechanical decoupling of the two closing elements increases the reliability,

■ both closing elements are each acted upon by a prestressed spring element and thus both have a quick-closing function, ^■ The throttle body of the first closing element also assumes a control or modulation function to adapt the gas flow to variable heat loads and

^■ The drive of the first closing element is designed as a linear drive and the drive of the second closing element is designed as an electromagnet.

The objectives and advantages of this invention will become better understood and appreciated after a careful study of the following detailed description of the preferred non-limiting example embodiments of the invention herein, together with the accompanying drawings, in which:

1 shows a sectional view of the gas control and safety valve with an arranged inside the engine spindle-nut system in the open position of the two closing elements,

Fig. 2 is a sectional view of the gas control and safety valve with a spindle-nut system disposed within the engine in the closed position of the two closing elements and

3 shows a sectional view of the gas control and safety valve with a spindle-nut system arranged outside the engine in the closed position of the two closing elements.

Figures 1 and 2 show one and the same gas control and safety valve according to the invention with a spindle-nut system arranged within the engine in each case in a sectional view in the closed position and in the open position. The gas control and safety valve consists of a two-part housing with a first housing part 1.1 and a second housing part 1.2. Both housing parts 1.1 and 1.2 are bolted together in their coupling region on their outer sides and sealed. At the end of the first housing part 1.1, the inlet channel 2 with the in Flow direction of the gas adjoining inlet chamber 3 placed. At the end of the second housing part is the outlet chamber. Within the housing, the first, acting in the direction of the inlet channel 2 closing element and the second, acting in the direction of the outlet channel closing element are placed as central components whose axes are spaced apart and in a straight line one behind the other between the inlet channel 2 and the outlet channel 4 extend , The electrically controllable first closing element extends in the first housing part 1.1, starting from the coupling region 19 to the inlet chamber 3 and the electrically controllable second closing element extends in the second housing part 1.2, starting from the coupling region 19 to the outlet chamber 4. Within the gas control and safety valve, the gas flows in a substantially annular channel 5, which extends from the inlet chamber 3 to the outlet channel 4, wherein the current-carrying components are placed in the gas flow without the use of a gas-tight sealing sleeve. The first closing element has a spindle 15 of a linear drive 15 formed drive axle 15.1, at the end of a throttle body 8 and at the opposite end, respectively, in the coupling region of the two housing parts 1.1, 1.2, the first spring element 7 is placed. The stepping motor further comprises the windings 16 of the electric motor 15 with the unspecified rotor, which is coupled to the translationally moving drive axle 15.1. The conversion of the rotational movement of the rotor in a translational movement of the drive axle 15.1 is thus carried out within the electric motor 15 by means of the spindle-nut system. The second closing element, in contrast, comprises a closure body 10 connected to a hollow armature 9, the hollow armature 9 being located in a cylinder-like cavity 18 surrounding a field winding 17 of the hollow armature 9 formed as part of an electromagnet and against the force of the second spring element 12 placed inside the hollow armature 9 is arranged working. By means of their associated spring elements 7, 12 close the two closing elements independently in the de-energized state abruptly the gas control and safety valve. However, the first closing element is used in addition to the modulation of the gas flow using the linear drive. The throttle body 8 of the first closing element is designed to be axially movable between an open position and a closed position in the inlet chamber 3. In the closed position of the gas control and safety valve according to FIG. 1, the throttle body 8 sits by means of its sealing surface 8.1 on a valve seat 13 arranged at the end of the inlet chamber 3. The closure body 10 closes in the closed position, the outlet chamber by means of its sealing surface 11 which is seated in a gas-tight manner on a valve seat 14 arranged at the beginning of the outlet channel 4. The valve seat 13 and the sealing surface 8.1 of the throttle body 8 are each formed annularly. In the open position of the throttle body 8 according to FIG. 2, an annular gap for the inflowing gas is formed between the valve seat 13 and the throttle body 8. The throttle body 8 preferably has a conical shape. In the coupling region 19 of the first housing part 1.1 and the second housing part 1.2 a partially extending over the cross section of the gas control and safety valve wave washer 6 is provided, which is sandwiched between the mutually facing end faces of the two closing elements. The corrugated spring washer 6 thus partially contacts both closing elements and primarily ensures the compensation of the axial tolerances of the two closing elements. Secondary, it generates the required contact pressure, respectively the bias, of the two closing elements on the associated housing inner wall.

Fig. 3 shows a sectional view of the gas control and safety valve with a arranged outside the electric motor 15 spindle nut system in the closed position of the two closing elements using the reference numerals of Figures 1 and 2. The basic structure of the gas control and safety valve corresponds to 2, but with the difference that the electric motor 15 has a motor shaft 15.2, at the end of the spindle-nut system outside of the electric motor 15th is placed. The conversion of the rotational movement of the motor shaft 15.2 in a translational movement of the throttle body 8 is thus carried out outside the electric motor 15 by means of the spindle-nut system.

LIST OF REFERENCE SIGNS

1 housing

1.1 first housing part

1.2 second housing part

2 inlet channel

3 inlet chamber

4 exhaust duct

5 channel

6 wave washer

7 first spring element

8 throttle body

8.1 sealing surface of the throttle body

9 anchors

10 closure bodies

11 sealing surface of the closure body

12 second spring element

13 valve seat of the throttle body

14 valve seat of the closure body

15 linear drive, electric motor

15.1 drive axle

15.2 Motor shaft

16 windings of the motor

17 excitation winding of the armature

18 cavity

19 coupling area

20 annular gap

Claims

A gas control and safety valve for burners of a modulatable gas heater, at least comprising a housing (1) with two controllable closing elements whose axes are spaced apart and extend serially in gas flow direction one behind the other between an inlet channel (2) and an outlet channel (4) of the housing , and both closing elements independently of each other by means of an associated spring element (7, 12) in the de-energized state abruptly close the gas control and safety valve, and in addition to the modulation of the gas flow serving first closing element a throttle body (8) and spaced therefrom the first spring element (7 ), wherein the first closing element is driven by a spindle-nut system coupled to an electric motor (15) with at least one excitation winding (16), and in that the second closing element has a closure body (10) connected to an armature (9), wherein the armature (9) in a cylinder-like cavity (18) and working against the force of the armature (9) acting second spring element (12) is arranged, and this cavity is surrounded by a formed as part of an electromagnet exciter winding (17) of the armature (9). 2. Gas control and safety valve according to claim 1, characterized in that the current-carrying components are placed in the gas flow without using a gas-tight sealing sleeve. 3. Gas control and safety valve according to claim 2, characterized in that as current-carrying components, the exciter winding (16) of the stepping motor (15) of the first closing element and the field winding (17) of the armature (9) of the second closing element are provided. 4. Gas control and safety valve according to one of claims 1 to 3, characterized in that the armature (9) is designed as a hollow armature, wherein the hollow armature (9) in the cylinder-like cavity (18) against the force of within the hollow armature (9 Placed second spring element (12) is arranged to operate. 5. Gas control and safety valve according to one of claims 1 to 4, characterized in that the spaced-apart axes of the two controllable closing elements are arbitrarily placed in the housing (1). 6. Gas control and safety valve according to claim 5, characterized in that the spaced-apart axes of the two controllable closing elements orthogonal, parallel or axially in a straight line one behind the other in the housing (1) are placed. 7. Gas control and safety valve according to claim 6, characterized in that in the formation of the gas control and safety valve with axially in a straight line behind one another arranged closure elements, a wave washer (6) is provided for the purpose of balancing the axial tolerances and to ensure a required contact pressure of the two closing elements on the housing wall is sandwiched between the mutually facing end faces of the two closing elements. 8. Gas control and safety valve according to one of claims 1 to 7, characterized in that in the gas flow direction of the inlet channel (2) is arranged downstream of an inlet chamber (3), wherein in the closed position of the gas control and safety valve of the throttle body (8) by means of its sealing surface ( 8.1) on one at the end of Inlet chamber (3) arranged valve seat (13) and the closure body (10) by means of its sealing surface (11) on a arranged at the beginning of the outlet channel (4) valve seat (14) gas-tight manner. 9. Gas control and safety valve according to one of claims 1 to 8, characterized in that the throttle body (8) between an open position and a closed position in the inlet chamber (3) is axially movable. 10. Gas control and safety valve according to one of claims 1 to 9, characterized in that the valve seat (13) and the sealing surface (8.1) of the throttle body (8) are each annular, wherein in the open position of the throttle body (8) is between the valve seat (13) and the throttle body (8) forms an annular gap for the incoming gas. 11. Gas control and safety valve according to one of claims 1 to 10, characterized in that the housing (1) in two parts with a first housing part (1.1) and a second housing part (1.2) is formed, wherein the first closing element in the first housing part (1.1 ) and the second closing element in the second housing part (1.2) is placed. 12. Gas control and safety valve according to one of claims 1 to 11, characterized in that the spindle-nut system is disposed either within the electric motor using a drive axle (15.1) or outside of the electric motor using a motor shaft (15.2).