JPH0777313A - Gas mixing device - Google Patents

Abstract

PURPOSE: To provide a gas mixer which can mix gases easily, economically and accurately at a constant mixing ratio even if the flow rate fluctuates considerably. CONSTITUTION: A gas mixer comprises a flow duct being coupled with a fan and having inlet and outlet ends for main gas flow wherein the flow duct is an enlarging duct 25 containing a valve element 27 for the air spreading in the lateral direction and the element 27 is guided to move coaxially with the enlarging duct. The air valve element 27 is arranged reversely to the flow direction and coupled with an enlarging duct 30 which is coupled with a mixture gas supply pipe 8 so that the mixture gas can be supplied depending on the position of the air valve element 27 in the enlarging duct 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow duct connected to a flow generator such as a fan and having an inlet end for a main gas flow, and a mixed gas for supplying a predetermined amount of the mixed gas to the main gas. And a gas blending device having a blending unit.

[0002]

2. Description of the Related Art Heretofore, such a gas blending device is generally known and used for adding flammable gas such as natural gas to air for combustion in a burner of a heating system, for example. Here, the mixed gas mixing unit is formed by, for example, a gas injector connected to a gas supply pipe to which the flammable gas is supplied at a predetermined pressure. Then, an accurate mixing ratio of the main gas and the mixed gas can be adjusted.

[0003]

However, special applications call for the ability to vary the amount of gas mixed. For heating systems, it is already known to use burners that can operate at lower or higher capacities depending on the conditions. A complex control system is required to obtain a precisely defined gas-air mixture at both low capacity and maximum load. In many cases, the associated costs are an obstacle to the use of such variable gas blenders.

The object of the present invention is therefore to provide a gas blending device of the above-mentioned type, which makes it possible to mix gases simply and economically with an exactly constant mixing ratio, even if the flow rates vary considerably. That is.

[0005]

The above-mentioned object is achieved by the gas blending device according to the first aspect of the present invention. That is, the main gas valve element is positioned in the divergent flow duct depending on the flow rate of the gas flow in the flow duct resulting from the operation of the flow generator. When a large amount of gas flows into the duct, the main gas valve element is located in a wider portion of the flow duct. The position of the valve element for the main gas is a measurement of the flow rate of the flowing gas, so that the mixed gas preparation unit supplies the mixed gas in an amount adapted to the flow rate of the gas. Thus, an optimum mixing ratio is obtained over a very wide flow range of the main gas.

The features of claim 2 result in a very simple device. When a large amount of main gas flows, the main gas valve element is located in a wider part of the main gas duct,
At the same time, since the mixing valve element is located in the wider part of the mixed gas duct, a proportionally large amount of mixed gas can flow.

According to the third aspect of the present invention, transportation and sealing which require frequent maintenance are unnecessary.

[0008] Claim 4 characterizes a very favorable further development. Due to the integrally connected valve element for the mixed gas and the valve element for the main gas, their movement is not disturbed by friction. Therefore, there is no risk that an incorrect mixing ratio will occur due to malfunction of the valve element.

With the arrangement according to claim 5, further simplification is achieved with increased reliability. With this configuration, the mixed gas valve element and the main gas valve element can move freely. This element forms the only moving part of the gas dispensing device.

The present invention further comprises means for forming a flow duct connected to the fan, and the gas blending device, the burner and the heat transport medium according to any one of claims 1 to 5 are arranged in order along the flow direction. The present invention relates to a heating device having at least a heat exchanger that can flow through, and provides such a heating device. The inlet end of the gas blender communicates with the atmosphere, and the mixed gas supply pipe is connected to a flammable gas source.
This heating device can be operated with low capacity or high capacity depending on the conditions, and high efficiency is achieved under all set conditions.
At the same time, this heating device can be manufactured economically.

[0011]

The gas blending device of the present invention used in a heating device will be described in detail below with reference to the illustrated embodiment.

The apparatus 1 shown in FIG. 1 is a so-called high-efficiency boiler having a flow duct 2 in which gas is transported by a built-in fan 6 in the flow duct. A gas blending device 3, a burner 4 of a complete premix type in this embodiment, a heat exchanger 5 and the fan 6 are sequentially arranged along the flow duct 2 in the flow direction. Fan 6
The supplied combustion gas is discharged from the suction pipe 7. In another embodiment, the fan 6 may be mounted in the flow duct before the burner 4. In this case, the fan is not exposed to high temperatures and condensate.

A heating water supply pipe 11 and a heating water discharge pipe 12 are connected to the heat exchanger 5.
A radiator and a convection radiator are connected to these pipes by a known method in order to send the heat supplied to the heating water in the heat exchanger 5 to a desired location.

In the gas blending device 3, the air sucked by the drive of the fan 6 is mixed with the gas from the gas supply pipe 8 at a predetermined desired mixing ratio so that optimum combustion occurs.

An electrically operated gas valve 9 for opening and closing the gas supply is attached to the gas supply pipe 8. Further, a pressure reducing valve 10 that keeps the gas pressure in the gas supply pipe 8 at a constant value is attached to the gas supply pipe 8.

The device 1 as a whole is controlled by a control device 15, in which only a few connecting lines are shown schematically. The control device 15 includes a flow rate sensor 16, an ignition device 19, the above-described electric valve 9 for gas, and a fan 6.
Are connected. Flow sensor 16 may be a pressure difference sensor responsive to a pressure difference between lines 17 and 18. These lines 17, 18 are connected to the flow ducts 2 on opposite sides of the burner and heat exchanger assembly. As soon as the fan 6 is switched on by the control device 15, the flow in the duct 2 starts. This flow creates a pressure difference through the burner 4 and the heat exchanger 5, and thus a pressure difference between the lines 17,18. This pressure difference is detected by a sensor 16, which produces an associated output signal to the controller 15. Then, the control device 15 activates the valve 9 for gas and the ignition device 19 so that the gas is added to the flow of air and the mixture of air and gas is ignited on the surface of the burner 4. The hot combustion gas flows through the heat exchanger 5 and heat is transferred to the heating water in the heat exchanger in a known manner. The cooled combustion gas is carried to the suction pipe 7 by the fan 6.

If a detector (not shown) instructs the control device 15 to generate, for example, a very small amount of heat, the control device 15 operates the fan 6 at a low speed. On the contrary, when a large amount of heat is required, the fan 6 is switched to the high speed operation side. In these extreme situations of low speed and high speed, and in the situation between them, a constant mixing ratio of air and gas is always obtained in the gas blending device 3, which is an air mixer.

As can be seen from FIG. 2, which shows a preferred embodiment of the gas blending device according to the invention, the object of the invention is achieved in a very simple, effective and reliable manner.

The gas blending device 3 comprises a housing 24 forming a divergent duct 25. This Suehiro duct 25
Is connected at its wide end to the flow duct 2 and forms part thereof. The narrow end of the divergent duct 25 is connected to an air supply opening 26 that communicates freely with the atmosphere. In the divergent duct 25 an air valve element 27 is housed which extends laterally of this duct. This air valve element 27 is coaxial with the duct 25,
That is, it can be moved vertically as can be seen from FIG. The air valve element 27 includes a rod-shaped gas valve element 28.
This gas valve element projects into a similar divergent duct 30 of a gas regulator housing 29 fixed to the gas blender housing 24. The gas supply pipe 8 is connected to the narrow end of the divergent duct 30.

The gas blending device 3 shown in FIG. 2 operates as follows.

Thanks to the vertical arrangement of the gas blending device as shown in FIG. 2, the integrally connected air valve element 28 and gas valve element 28 are downward, ie the divergent duct 2.
5 and 30 are moved in the direction toward the narrow ends. When there is no flow through the duct 25, the valve elements are each in their lowest position shown in broken lines, where the air duct 25 and the gas duct 30 are both closed.

Now, as soon as the fan is switched on to a predetermined speed, air begins to flow in the air duct 2. Depending on the strength of this flow, the air valve element 27 is forced upwards within the divergent duct 25 against the gravity acting on its valve assembly. Air valve 27
The higher the distance is, the larger the gap between the periphery of the air valve and the wall of the duct 25 is, so that the upward force is reduced, so that, for a given air flow rate, At a certain height of the air valve element 27 in the duct 25, the equilibrium state is adjusted. Since the air valve element 27 is directly connected to the gas valve element 28, the corresponding position of the gas valve element 28 in the gas duct 30 is adjusted so that the lower end of the gas valve element 28 is adjusted. The gap between the and the wall of the gas duct 30 is adjusted. The flow rate of the gas flowing through the gap between the lower end of the gas valve element 28 and the wall of the divergent duct 30 depends on the width of this gap,
It therefore depends on the vertical position of the gas valve element 28. By choosing the apex angle of the cone of the gas duct 30 in combination with that of the air duct 25,
At each position of the air valve element 27, which is determined by the air flow in the duct 25, it is possible to achieve supplying the correct amount of gas to the divergent duct 25 so as to obtain the desired mixing ratio. In this way, exact mixing ratios can be achieved even with very wide variations in air velocity. As can be clearly seen in FIG. 2, the gas blending device is of a particularly simple construction in that it has only one moving element which is free to move freely into a proper position in the unhindered state of use. Therefore, the gas blending device described above can be manufactured economically and reliably operates for a long period of time.

The dimensions of the cones of the air duct 25 and the gas duct 30 can be determined by testing and depend to some extent on the implementation of the heating system. The control range of the gas blender must of course be adapted to the desired control range of the heating device.

The desired mixing ratio setting can be obtained by adjusting the pressure reducing valve 10.

The depicted apparatus is a preferred embodiment and the invention is not limited to this embodiment. For example,
The gas blending device need not be placed vertically, but can be placed horizontally or at another location. However, in this case, it will be necessary to mount a spring for urging the air valve toward the narrow end of the divergent duct 25. Also, the direct connection of the air valve element 27 to the gas valve element 28 is a preferred embodiment and an indirect connection may be used.

The gas blending device according to the invention is particularly, but not exclusively, suitable for use in heating devices. INDUSTRIAL APPLICABILITY The present invention can be applied to all situations in which a mixed gas must be added to a main gas at a constant ratio while the flow rate of the main gas greatly changes.

[Brief description of drawings]

FIG. 1 is a schematic view of a heating device using an embodiment of a gas blending device according to the present invention.

FIG. 2 is an enlarged perspective view in which the gas blending device is partially broken.

[Explanation of symbols]

1 ... Heating device, 2 ... Flow duct, 3 ... Gas blending device,
4 ... Burner, 5 ... Heat exchanger, 6 ... Fan, 7 ... Suction tube,
8 ... Gas supply pipe, 9 ... Valve, 10 ... Pressure reducing valve,
11 ... Supply pipe, 12 ... Discharge pipe, 15 ... Control device, 16 ... Flow rate sensor, 17, 18 ... Line, 19 ... Ignition device, 24, 29 ... Housing, 25, 30 ... Suehiro duct, 26 ... Air supply opening , 27 ... Air valve element,
28 ... Gas valve element.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ralph Voltering, Federal Republic of Germany Day-4422 Ahaus, Schlesienstraße No. 2 (72) Inventor Frank Voltering Federal Republic of Germany Day-4422 Ahaus, Schü Rage Enstraße No. 2

Claims (7)

[Claims] 1. A gas blending device comprising a flow duct connected to a flow generator such as a fan and having an inlet end and an outlet end for the main gas flow, the flow duct diverging toward the flow direction. The main gas valve element that extends in the lateral direction is accommodated in the flow duct, and the main gas valve element is
Guided to move coaxially with the flow duct, the main gas valve element is arranged in a direction opposite to the flow direction and connected to the mixed gas blending unit,
This mixed gas mixing unit is connected to a mixed gas supply pipe, and is capable of supplying a mixed gas in an amount corresponding to the position of the main gas valve element in the duct. A gas blending device. 2. The mixed gas blending unit is fixed to the mixed gas duct, which widens toward the direction parallel to the flow direction, and the main gas valve element, and is coaxial with the main gas valve element. A mixed gas valve element that is guided so as to move, wherein the mixed gas duct has one end with a small diameter connected to a gas source at a constant pressure and the other end connected to the flow duct. The gas blending device according to claim 1. 3. The gas blending device according to claim 2, wherein the mixed gas duct is arranged coaxially with the flow duct and flows directly into the flow duct. 4. The mixed gas valve element is rod-shaped, the main gas valve element is a disc fixed to the mixed gas valve element, and the rod-shaped mixed gas valve element is The gas blending device according to claim 3, wherein the gas blending device is guided so as to move freely in the duct for mixed gas. 5. The flow direction is oriented vertically upwards and the main gas valve element is arranged to be gravity loaded in a direction opposite to the flow direction. 4. The gas blending device according to any one of 4 above. 6. A means for forming a flow duct connected to a fan, comprising: means for forming a flow duct in the flow direction in order.
In the heating device having at least the gas blending device according to any one of claims 1 to 3, a burner, and a heat exchanger through which a heat transport medium can flow, the inlet end of the gas blending device communicates with the atmosphere, and the mixed gas supply pipe. Is a heating device characterized in that it is connected to a flammable gas source. 7. A control in which an electrically operated gas valve attached to the mixed gas supply pipe, an ignition device of the burner, and a flow sensor for detecting a flow in the flow duct are connected. The heating device according to claim 6, further comprising a device, wherein the control device activates the gas valve and the ignition device in response to an output signal of the flow sensor.