JPH07332657A - Gas volume detection device - Google Patents

Abstract

PURPOSE:To correct variations in the output of a pressure sensor and detect the amount of gas with accuracy. CONSTITUTION:This detection device comprises a pressure sensor 1 installed in a gas passage and a gas volume computation means 6 which computes the amount of gas based on the difference between an output value of a pressure sensor 1 directly before operating a gas hot water supply heater and an output value of the pressure sensor 1 when operating the gas water supply heater and temperature-corrects the amount of gas based on a temperature signal 7 installed near the pressure sensor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas amount detecting device for detecting the gas amount of a domestic gas combustor.

[0002]

2. Description of the Related Art Conventionally, in this type of gas amount detection, as shown in FIG. 1, the output value of the pressure sensor 1 is used as it is to calculate the gas amount. The configuration will be described with reference to the gas water heater of FIG. Reference numeral 2 is a known control device, and a microcomputer is used for its signal processing. The controller 2 controls the amount of gas supplied to the burner 4 by driving the electronic gas proportional valve 3. At this time, the control device 2 detects the gas pressure value with the pressure sensor 1 and drives the electronic gas proportional valve 3 so as to obtain a predetermined gas amount while calculating the gas amount. In addition, 5 is a heat exchanger which converts water into hot water by the high temperature combustion exhaust gas generated in the burner 4.

Further, the control device 2 uses the output value of the pressure sensor 1 as it is to calculate the gas amount.

[0004]

However, in such a conventional gas amount detecting device as described above, the pressure sensor 1 has the structure shown in FIG.
Since it has a large offset amount (the output value of the pressure sensor when the pressure is 0) and the change in the output characteristics due to temperature as shown in, the pressure sensor is selected and used to detect the accurate gas amount. Therefore, the pressure sensor becomes expensive, and an inexpensive and accurate gas amount detecting device cannot be obtained.

The present invention has been made to solve the above problems, and an object thereof is to provide an inexpensive and accurate gas amount detecting device.

[0006]

In order to achieve the above object, the first means of the present invention is to provide an output value of a pressure sensor immediately before operating a gas water heater and a pressure when the gas water heater is operating. A gas amount calculation means for calculating the gas amount from the difference from the output value of the sensor is provided.

The second means is that a temperature sensor is provided in the vicinity of the pressure sensor, and temperature correction means for correcting the gas amount by the signal of the temperature sensor is provided.

[0008]

According to the first aspect of the present invention, the amount of gas is calculated from the difference between the output value of the pressure sensor immediately before operating the gas water heater and the output value of the pressure sensor during operation. Therefore, the offset amount of each pressure sensor can be canceled.

According to the second means, the influence of the temperature can be reduced by detecting the temperature of the pressure sensor and correcting the output value of the pressure sensor according to the temperature.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 2 is a known control device, and a microcomputer or the like is used for its signal processing. The control device 2 is connected to drive the electronic gas proportional valve 3, and the burner 4 is connected to the electronic gas proportional valve 3. The gas amount calculation means 6 is connected to receive the signals from the pressure sensor 1 and the temperature sensor 7, detect the gas pressure value, calculate the gas amount, and send the result to the control device 2. The temperature sensor 7 may be provided inside the pressure sensor. In addition, 5 is an exchanger which changes water into hot water by high temperature combustion exhaust gas generated in the burner 4.

To explain the operation of the above structure, the gas amount calculating means 6 operates as follows according to the flow chart of FIG. Step 1 ... The temperature of the pressure sensor 1 is measured by the signal of the temperature sensor 7. Step 2 ... It is judged from the signal from the control device 2 whether the equipment is in operation. Step 3: The pressure is measured by the signal from the pressure sensor 1. When the temperature correction is calculated and the equipment is stopped, this pressure value is treated as zero. If the equipment is in operation, the pressure value calculated by the same operation is used as an effective value. By performing such a correction calculation, even a pressure sensor having a large variation has a small variation as shown in the corrected pressure sensor characteristic diagram of FIG. Step 4 ... Pressure = pressure value (present) -pressure value (0)

[0012]

[Equation 1]

K: A constant determined by the gas passage resistance of the equipment Step 5 ... Outputs the gas amount to the controller 2. The control device 2 judges whether or not the gas amount is appropriate by the gas amount signal of the gas amount calculating means 6, and if not, drives the electronic gas proportional valve 3 to increase or decrease the gas amount and supply the required gas to the burner 4. To do.

As described above, according to the gas amount detecting apparatus of the embodiment of the present invention, even if the pressure sensor 1 has a variation, the pressure detecting characteristic can be made a characteristic with little variation, and the gas amount can be detected with little variation.

[0015]

As is apparent from the above description, in the gas amount detecting device according to claim 1 of the present invention, even if there is a variation in the offset amount of the pressure sensor, it can be easily canceled by devising the arithmetic processing and is inexpensive. Therefore, an accurate gas amount detecting means can be provided.

Further, according to the second aspect of the present invention, it is possible to provide a gas amount detection device having a small temperature dependency in the characteristic by the temperature sensor and the arithmetic processing even if the characteristic of the pressure sensor has the temperature dependency.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas amount detection device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a corrected pressure sensor of the detection device.

FIG. 3 is a flowchart of the detection device.

FIG. 4 is a configuration diagram of a conventional gas amount detection device.

FIG. 5 is a characteristic diagram of a pressure sensor of the detection device.

[Explanation of symbols]

 1 Pressure sensor 2 Control device 6 Gas amount calculation means 7 Temperature sensor

Claims (2)

[Claims] 1. From the difference between the output value of the pressure sensor provided in the gas passage and the output value of the pressure sensor immediately before operating the gas water heater and the output value of the pressure sensor when operating the gas water heater. A gas amount detecting device comprising a gas amount calculating means for calculating a gas amount. 2. The gas amount detecting device according to claim 1, wherein a temperature sensor is provided in the vicinity of the pressure sensor, and the temperature of the gas amount is corrected by the signal of the temperature sensor.