EP0981025A2 - Device and method for adjusting the rotational speed of a fan of a gas heater, especially a gas boiler - Google Patents

Abstract

Experimentally derived air flow rates for different exhaust hose lengths are stored in an electronic memory (28) and a temperature comparator (32) is fed with the reference value (33) and actual output value (39) from the heat exchanger (29), and the fan (40) is controlled by an output signal (43). The gas supply to the burner is controlled by a valve (30) and the fan speed by a regulator (41) and the comparator system matches the fan speed, hence the air flow, to the gas burning rate for the length of exhaust hose used.

Description

The invention relates to a gas heating device and a Procedure for adjusting the speed of a fan Gas heating device, in particular a gas boiler, according to the respective preamble of independent claims 1 and 11.

With modulating gas heaters, i.e. Gas heaters where the amount of heat to be given off by the thermal bath in the form of hot water can be set or regulated, it is necessary to the entire load range or the range adjustable Gas flows to set an optimal air ratio at which the Emissions are as low as possible. For fan-assisted Gas heaters can measure the air ratio, i.e. the amount of through the blower supplied air, be adjusted so that a Sets efficiency that is as high as possible. Here is, however note that the efficiency is not set too high as otherwise the exhaust gases will condense, causing damage due to corrosion in the gas boiler and / or in the connected air-exhaust system. This is done at known fan-assisted gas heaters the fan speed regulated in a suitable manner depending on the gas flow. In the laboratory, an optimized blower characteristic for the the maximum possible length of the air-exhaust system and the speed of the fan of the gas boiler is corresponding to this Characteristic curve depending on the specific gas flow set.

However, because the end customer has different lengths of the air-exhaust system with which the flue gas heater is installed the pressure loss of the air-exhaust system is not that with the delivery condition set maximum possible length of the Air exhaust system. So does the length of the air exhaust system that has been installed at the end customer, by the maximum possible length of the system, which is the rule the combustion air ratio is no longer optimal. Therefore, it is So far it was necessary for the end customer to take special measures for optimization taken for the specific air-exhaust system are to be observed, taking the aforementioned boundary conditions into account are.

Several methods are known for the optimization. So be For example, the kit of the air-exhaust system exhaust throttle orifices enclosed with the installer during installation must assemble. In practice, however, this is often forgotten. Checking whether the panels have been installed correctly, is complex after the installation of the thermal bath and the air-flue gas guide and only possible if the air-exhaust system partially dismantled.

In another method, the flow resistance of the Air exhaust system by means of an adjustable aperture, such as in the exhaust manifold of the gas boiler. An aperture whose Flow cross section is adjustable, is from DE 197 11 687 A1 known. Such an aperture is very expensive to construct and therefore expensive.

Another known procedure is the fan speed of a gas boiler fan slowly increase until a switching point of an air pressure switch is reached. The The speed at the switching point of the pressure switch is then in one Control is calculated and a speed characteristic is determined from this. This process is relatively complex because of the large number of influences such as Component tolerances, temperature influences or leaks in a vacuum chamber the result distort. Therefore, in practice it is often not the right one Air ratio set. In addition, the air ratio is corrected Local gas boiler hardly possible anymore.

The object of the present invention is a gas heating device and a method for operating such To provide a device that allows in a simple manner the air ratio, taking into account that specific to the end customer optimize the existing air-exhaust system.

The present object is achieved by the gas heating device according to the independent claim 1 and by the method according the independent process claim 11 solved.

Advantageous embodiments are in the independent claims assigned dependent claims.

An important aspect of the invention is in or on to provide the gas heating device with an electronic memory, the multiple target characteristics or some values of these target characteristics for the fan speed depending on the load and / or the gas flow of the gas heating device for Different lengths of the supply air and / or exhaust gas (pipe) line saves. These target characteristics or their values are determined in the laboratory and stored in the memory. After installation the gas heater and the associated supply air and / or Flue gas pipe through the installer at the end customer the installer determines the specific length of the Line or lines measured and in an input device provided in or on the gas heating device entered. Depending on the installer The length entered is the target characteristic curve stored in the memory for the corresponding length or one of the entered Length approximate length as the target characteristic for the concrete Installation used by the end customer. Based on this Target characteristic or the values of such a characteristic a comparison between the fan's actual fan speed Fan of the gas heating device installed at the customer and the target value according to this by entering the concrete Length of the selected target characteristic curve. Gives way to If the actual fan speed is lower than the target speed, this is recognized a comparison device and controls a regulation for the Fan in such a way that its speed is the target fan speed adapts and the optimal air ratio adjusts itself automatically. In the case of such a regulation, for example act as a thyristor actuator.

Another important aspect of the invention is in the memory several of the specified target characteristics or associated Store values, whereby in the delivery state of the gas heating device one of these target characteristics or the characteristic corresponding values as a benchmark for comparing the Actual fan speed with the target fan speed used becomes. This factory setting of a target characteristic for the delivery state of the gas heating device achieved that even if the installer after assembly the gas heater should forget the specific length of the supply air and / or exhaust gas (pipe) line available at the end customer enter damage to the gas heating device or the exhaust pipe is prevented. Forgets the installer Enter the specific length of the supply air and / or exhaust gas (pipe) line and thus the electronic pipe length adjustment, so the exhaust gas temperatures are lower than in the case where the installer forgets the known state of the art, the mechanical exhaust throttle orifices correct for short pipe lengths adjust because the speed of the exhaust fan or blower using a lower average value the target characteristic curve preset in the delivery state is set. Possible damage is then much less.

It is preferably the factory, in the delivery state preset target characteristic curve by a characteristic curve for a length of the supply air and / or exhaust gas (pipe) line, which has a length that is approximately in the middle between one permissible minimum length and a permissible maximum length lies. For example, the permissible minimum length is 1 m and the maximum allowable length is about 5 m, so would be preferred a target characteristic curve for the fan speed depending on the load or the gas flow of the gas heating device selected be that of the target characteristic for a supply air and / or Exhaust pipe corresponds to about 3 m. In the In practice, the deviation of the fan speed from this is according to the invention to the mean of a length for the supply air and / or Flue gas (pipe) line preset target characteristic about half as high, typically +/- 10%, as in the known Default setting at which the target fan speed for the maximum permissible length of the exhaust pipe in the factory in delivery condition is set, here typically + 20%, and the installer has no or an incorrect exhaust orifice assembled.

Fig. 1

fünf Soll-Gebläsekennlinien, d.h. die Soll-Gebläsedrehzahl einer Gasheizvorrichtung als Funktion des Gasdurchflusses für fünf verschiedene Längen der Abgas(rohr)-Leitung der Gasheizvorrichtung;

Fig. 2

ein Blockschaltbild einer erfindungsgemäßen Gasheizvorrichtung

The invention is explained in more detail below with the aid of two figures. Show it:

Fig. 1

five set fan characteristics, ie the set fan speed of a gas heating device as a function of the gas flow for five different lengths of the exhaust gas (pipe) line of the gas heating device;

Fig. 2

a block diagram of a gas heating device according to the invention

In Fig. 1 there are blower characteristics for the supply air blower (not a modulating gas heating device (not shown), a gas boiler. On the X axis is that Load or the gas flow through the gas heater in Percent applied. The fan speeds are on the Y axis of the gas heater per minute. In the corresponding Coordinate system 1 is a first characteristic curve 2, a second characteristic 3, a third characteristic 4, a fourth characteristic 5 and a fifth characteristic 6 indicated. The first characteristic 2 shows the target fan speed for the specific gas heating device as a function of the load or the gas flow through the gas heating device for gas flows or Loads from 0% to 110% and represents a determined in the laboratory optimal blower characteristic for the gas heating device in question and an exhaust pipe with a length of im. For optimal operation of the gas heating device in question with a supply air and / or exhaust pipe length of 1 m is corresponding provided the blower characteristics shown in Fig. 1, the fan of the gas heating device in question with a gas flow between 0% and 40% with a speed of about 1,300 To operate revolutions per minute. In the range from 40% to 65% of the gas flow should be the speed for optimal operation linear from about 1,300 revolutions per minute to about Rise 1,680 revolutions per minute. In the range of approx. 65% up to about 100% of the gas flow should be the speed of the fan increase to about 1,850 revolutions per minute and remains with an overload in the range of 100% to 110% of the gas flow largely constant. The target characteristic curve 3 shows a Laboratory-optimized characteristic curve for an exhaust pipe length of 2m Characteristic curve 4 applies to an exhaust pipe length of 3m, the characteristic curve 5 applies to an exhaust pipe length of 4m and characteristic 6 applies finally for an exhaust pipe length of 5m.

The target blower characteristics 3, 4, 5 and 6 are in the above Sequence from curve to curve along the Y-axis shifted upwards compared to characteristic curve 2. The course of the characteristic curves 3, 4, 5 and 6 corresponds however roughly the course of the characteristic curve 2 described.

The target fan speed for the target characteristic curve is 3 at a gas flow of 0%, about 1,400 revolutions per minute, and with a gas flow of 100% about 2,000 revolutions per minute. With the target characteristic curve 4, about 0% should 1,550 revolutions per minute, for 100% of the maximum gas flow about 2,200 revolutions per minute can be set. For target characteristic curve 5, about 1,680 revolutions apply at 0% per minute and for 100% about 2,400 revolutions per minute.

After all, there are about 1,800 for the target characteristic curve 6 at 0% Revolutions and for 100% about 2,600 revolutions per minute.

These characteristics or some or all of the values of these characteristics are stored in a memory (not shown) in or on the gas heating device is provided, stored. It understands that the fan characteristics shown in Fig. 1 are natural of the concrete gas heater, the cross section of the Exhaust pipe and the blower depend and here only as an example are shown.

Furthermore, a device for adjustment is in the gas heating device the gas flow through the gas heating device or a device for adjusting the load on the gas heating device (not shown), an electronic scheme (not shown), like a thyristor actuator, for adjustment the speed of the fan, a device for determining the Speed of the fan (not shown), and a device for comparison of the actual fan speed with the target characteristic for the relevant exhaust pipe length, corresponding to Fig. 1, provided.

During the operation of the gas heating device according to the invention determines the device for determining the speed of the fan the gas heater the current speed of the fan and provides information corresponding to this speed a target / actual value comparison device. The gas flow adjuster the gas heater provides the necessary Gas flow. The actual speed of the fan is in the Delivery state of the target speed according to the factory preset characteristic curve 4 for the specific load or adjusted the specific gas flow. The changes Load or the gas flow, the fan speed in the described manner of the corresponding target speed adapted to the characteristic curve 4.

2 is a block diagram of a gas heating device according to the invention shown. The block diagram of a gas heater 20 shows a temperature comparison device 32, a temperature controller 31 generating a modulation current, an electrically controllable gas fitting or gas valve 30, a burner / heat exchanger 29, a storage and comparison device 28, a speed comparison device 42, a Blower regulator 41 and a blower 40.

The target temperature is obtained via a target temperature input 33 set on the temperature comparison device 32. At the Burner / heat exchanger 29 is an actual value temperature measuring device (not shown) provided that the measured variable 39th the actual temperature at the burner / heat exchanger 29 an actual temperature input 34 of the temperature comparison device 32 supplies. Depending on the temperature comparison device 32 carried out comparison of the target temperature with the actual temperature is the temperature controller 31 via an output 35 of the temperature comparison device 32 a the temperature difference adequate differential signal supplied. At the exit 36 of the temperature controller 31 gives it a modulation current which increases if the actual temperature value is too low and reduced if the actual temperature value is too high becomes. The output 36 of the temperature regulator which emits the modulation current 31 is with the input of the electrically controllable Gas valve connected, which has a gas valve, which is in the In the event of an increasing modulation current, it opens further and in In the case of a decreasing modulation current accordingly closes or the amount of gas supplied to the burner / heat exchanger 29 increased or decreased. The temperature controller 31 at its output 36 also the modulation current Storage and comparison device 28 supplied. The Speicherund Comparison device 28 has an electronic memory, preferably an EEPROM. In the electronic memory are those of a first target characteristic curve 21 and a second Target characteristic curve 22, a third target characteristic curve 23, a fourth Desired characteristic curve 24 and a fifth desired characteristic curve 25 corresponding Value pairs saved. The target characteristic curves 21-25 give the target fan speed of the fan 40 as a function of from the temperature controller 31 to control the gas valve 30 emitted modulation current. So in the end also give the target characteristics shown in Fig. 2, the target fan speed as a function of gas flow to the burner of the gas heater on. The target characteristic curve 21 shows an optimized one in the laboratory Characteristic for an exhaust pipe length of 1m, the characteristic 22 applies to an exhaust pipe length of 2m, characteristic curve 23 applies for an exhaust pipe length of 3 m, characteristic curve 24 for an exhaust pipe length of 4m and the characteristic curve 25 finally for one Exhaust pipe length of 5m in analogy to that shown in Fig. 1 Set characteristic curves for the fan speed as a function of Gas flow to the burner of the gas heater.

The storage and comparison device 28 detects it the line 37 delivered at the output of the temperature controller 31 Modulation current and determined in the delivery state of the gas heating device based on the target characteristic curve 23 for an exhaust pipe length of 3m assigned value pairs that the recorded Modulation current corresponding target fan speed (see Y axis, which is the target fan speed in revolutions per minute and the X axis, which shows the modulation current in mA). The Storage and comparison device 28 performs a comparison of the detected or measured modulation current with the in it stored value pairs for the modulation current through, in Delivery condition of the gas heater based on the preset target characteristic curve 23 and gives a signal like a voltage or a current, starting at its output, that the setpoint fan speed corresponding to the modulation current actually recorded corresponds. That from the storage and comparison device 28 set target signal is a target fan speed input 43 of the speed comparison device 42 supplied as the target size. There is a measuring device on the blower 40 (not shown) provided the actual speed of the blower 40 detects or measures. Measured variable 47 of the actual speed of the fan 40 becomes the actual fan speed input 44 fed to the speed comparison device 42. Dependent on from the comparison result between target fan speed and The speed comparison device 42 gives the actual fan speed at its output 45 an output signal, such as a voltage or a current that represents the result of the comparison and controls the fan controller 41. With the blower regulator 41 it can be, for example, a thyristor actuator. The output 46 of the blower regulator 41 is connected to the blower 40 electrically connected and causes the fan 40 to rotate that determined by the storage and comparison device 28 Target speed based on the target characteristic curve used or corresponding pairs of values.

Again, it is understood that the values given in Fig. 2 for the target fan speed as a function of the modulation current to control the gas valve are only given as examples and of the specifically used components of the invention Detach gas heater.

It is contemplated that the gas heater and the exhaust pipe installer measures the length of the exhaust pipe and after installation in the gas heating device according to the invention via an input device (not shown) enters. Deviates the length of the exhaust pipe measured by the installer from the exhaust pipe length preset in the delivery condition from 3m, then the entered value of the exhaust pipe length approximate pipe length or the corresponding Target fan characteristic curve in an analogous manner to adapt the actual speed of the fan to the target speed of the fan.

Reference list

1

Coordinate system

2nd

first target characteristic curve in FIG. 1 for an exhaust gas (pipe) Cable length of 1m

3rd

second target characteristic curve in FIG. 1 for an exhaust gas (pipe) Cable length of 2m

4th

third target characteristic curve in FIG. 1 for an exhaust gas (pipe) Cable length of 3m

5

fourth nominal characteristic curve in FIG. 1 for an exhaust gas (pipe) Cable length of 4m

6

fifth target characteristic curve in FIG. 1 for an exhaust gas (pipe) Cable length of 5m

20th

Block diagram of a gas heater

21

first characteristic curve in FIG. 2 for an exhaust gas (pipe) Cable length of 1m

22

second characteristic curve in FIG. 2 for an exhaust gas (pipe) Cable length of 2m

23

third characteristic curve in FIG. 2 for an exhaust gas (pipe) Cable length of 3m

24th

fourth characteristic curve in FIG. 2 for an exhaust gas (pipe) Cable length of 4m

25th

fifth characteristic curve in FIG. 2 for an exhaust gas (pipe) Cable length of 5m

26

Gas heater blower control loop

27

Control loop of the burner of the gas heater

28

Storage and comparison device

29

Burner / heat exchanger

30th

electrically adjustable gas valve or valve

31

Temperature controller that generates a modulation current

32

Temperature comparison device

33

Setpoint temperature input of the temperature comparison device 32

34

Actual temperature input of the temperature comparison device 32

35

Output of the temperature comparison device 32

36

Output of the temperature controller 31

37

Line to the storage and comparison device 28

38

Pipe of the heating gas to the burner / heat exchanger 29

39

Measured variable of the actual temperature at the burner / heat exchanger 29

40

fan

41

Fan controller

42

Speed comparison device

43

Target fan speed input of the speed comparison device 42

44

Actual blower speed input of the speed comparison device 42

45

Output of the speed comparison device 42

46

Fan controller output 41

47

Measured variable of the actual speed of the fan 40

Claims (15)

Gas heating device, in particular a gas heater, with a blower for supplying (combustion) air depending on the gas flow, an electronic control for adjusting the speed of the blower, such as in particular a thyristor actuator, and a supply air and / or exhaust gas (pipe) -Management,
marked by an electronic memory for storing at least several values of at least one predetermined characteristic curve (FIG. 1) for the fan speed depending on the load condition and / or the gas flow of the gas heating device for a first length of the supply air and / or exhaust gas (pipe) line , a device for setting the current load condition or the gas flow of the gas heating device, a target / actual value comparison device which compares the actual value of the speed of the blower with the target value of the speed of the values of the stored target characteristic curve (Fig. 1) for the set load condition or gas flow, the comparison device emits an electrical signal and / or information which is fed to the electronic control system and the electronic control system adjusts the current speed to the target speed. Gas heating device according to claim 1,
characterized in that Values of several desired characteristic curves (FIG. 1) for different lengths of the supply air and / or the exhaust gas (pipe) line are stored in the electronic memory. Gas heating device according to claim 1 or 2,
characterized in that the length is 1m, 2m, 3m, 4m, 5m etc. (Fig. 1). Gas heating device according to one of claims 1 to 3,
marked by an input device, via which the actual length of the supply air and / or exhaust gas (pipe) line can be input, and which ensures that the comparison device the actual speed with values for the target speed of the target characteristic (Fig. 1st ) for the length in question. Gas heating device according to claim 4,
characterized in that the input device is an electrical switch or the like, which has a plurality of switch positions, each of which is assigned to a length. Gas heating device according to one of claims 1 to 5,
characterized in that the comparison device carries out a comparison on the basis of a target characteristic curve (FIG. 1) for a preset length (FIG. 1: characteristic curve 4) of a supply air and / or exhaust gas (pipe) line when the gas heating device is in the delivery state. Gas heating device according to claim 6,
characterized in that the preset length corresponds approximately to the middle between a permissible minimum and a permissible maximum length. Gas heating device according to claim 7,
characterized in that the permissible minimum length is approximately 1m, the permissible maximum length is approximately 5m and the preset length is approximately 3m. Gas heating device according to one of claims 4 to 8,
characterized in that the length entered via the input device is permanently stored in the memory, preferably an EEPROM, but can preferably be overwritten by a new entry. Gas heating device according to one of claims 6 to 8,
characterized in that the length preset in the delivery state of the gas heating device and / or preset values of a predetermined characteristic curve predetermined for this length are stored in a rewritable electronic memory, which is preferably also the EEPROM, which is used to store the length entered via the input device concrete supply air and / or exhaust gas (pipe) line is used. Method for adjusting the speed of a fan of a gas heating device, in particular a gas heater, which has a supply air and / or exhaust gas (pipe) line,
marked by a first step in which, in an electronic memory provided in or on the gas heating device, at least values of a first predetermined characteristic curve (FIG. 1) of the fan speed as a function of the load condition and / or the gas flow for a first length (FIG. 1 ) a supply air and / or exhaust gas (pipe) line are stored, a second step in which the load state and / or the gas flow is set, a third step in which the value of the fan speed of the target characteristic curve corresponding to the current load condition and / or the current gas flow is determined, a fourth step in which the actual fan speed is compared with the target fan speed, and a fifth step in which an electronic control adjusts the actual fan speed to the target fan speed. A method according to claim 11,
characterized in that the first target characteristic curve for a length (FIG. 1: characteristic curve 4) of the supply air and / or exhaust gas (pipe) line has been determined in advance and has been stored in the gas heating device in the delivery state, the length being approximately in the middle between a permissible one Minimum length and an allowable maximum length corresponds. Method according to claim 12,
characterized in that the permissible minimum length is approximately 1 m, the permissible maximum length is approximately 5 m and the target characteristic curve has been determined in advance for a length of approximately 3 m. Method according to one of claims 10 to 13,
characterized in that in a sixth step, the specific length of the supply air and / or exhaust gas (pipe) line is entered into an input device provided in or on the gas heating device, and In a seventh step, the values of a target characteristic of the fan speed as a function of the load and / or the gas flow of the gas heating device for the specific length or a length of the supply air and / or exhaust gas (pipe) line that comes close to this length for a comparison of the Actual fan speed is used with the target fan speed. Method according to one of claims 11 to 14,
characterized in that Integer multiples of a length, such as 1m, 2m, 3m, 4m, 5m etc., can be entered as a length specification in the input device and values for the target speed of the fan (FIG. 1) depending on the load and in the electronic memory / or the gas flow for each of these (permissible) lengths of the supply air and / or exhaust gas (pipe) line are stored.

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