JPH033805Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for automatically adjusting the maximum opening degree of a gas proportional valve used in a gas water heater having a function of proportionally controlling the temperature of hot water.

[Conventional technology]

In recent years, there has been a demand for gas water heaters that can provide a constant amount of hot water regardless of changes in the amount of hot water, and proportional control of gas has become necessary.

A gas proportional valve is generally used as a means of achieving proportional gas control. Here, the gas proportional valve is a valve whose opening degree, that is, the amount of gas, can be made variable in accordance with an input signal. but,
Gas proportional valves have large individual differences in the characteristics of valve opening relative to input signals, and the input signal for obtaining the same valve opening differs from gas proportional valve to gas proportional valve. On the other hand, the maximum hot water output number of gas water heaters must be kept to a certain value.
For this reason, in order to keep the maximum hot water output number constant for gas water heaters equipped with a gas proportional valve, it was necessary to adjust the maximum opening degree of the gas proportional valve for each machine. In other words, the conventional method for adjusting the maximum opening of the gas proportional valve was to operate a trimmer, etc. installed on the water heater's control circuit while monitoring the secondary pressure of the gas flowing into the burner, to obtain the maximum hot water output number. The maximum opening of the proportional valve was adjusted so that the amount of gas could be achieved.

[Problem that the invention attempts to solve]

Conventional gas proportional control type water heaters require a mechanism such as a trimmer to be provided on the circuit board to adjust the gas proportional valve, which increases the size of the circuit board and is disadvantageous in terms of cost. For adjustment work, measuring instruments and equipment are used to monitor the secondary pressure of the gas flowing into the burner.
Special equipment such as jigs was required. Furthermore, if the adjustment work is not carried out correctly, problems may occur in the combustion characteristics, which requires the operator's skill and takes a long time, resulting in problems in terms of cost and reliability.

[Means and examples for solving problems]

Hereinafter, the contents of the present invention will be explained using examples. FIG. 2 is an example of a control flowchart for realizing the present invention, and FIG. 1 is an example of a system for implementing the invention. This system consists of a gas passage consisting of a gas shutoff valve 8, a gas proportional valve 7, and a burner 9, a water passage consisting of a flow rate sensor 10, an inlet water temperature thermistor 5, an outlet water temperature thermistor 4, and a heat exchanger 6, and signals from each of the above sensors. from a control circuit 2 that processes actuators such as the gas proportional valve 7 and gas shutoff valve 8, and displays information on the remote controller 3, and a memory circuit 1 that stores the maximum opening degree of the gas proportional valve, etc. configured.

Next, a method for automatically adjusting the gas proportional valve 7 will be described. Immediately before the start of combustion, the control circuit 2 reads data from the memory circuit 1 and checks whether automatic adjustment of the gas proportional valve 7 has been completed. If the automatic adjustment has been completed at this time, the normal combustion operation is performed based on the upper and lower limit values of the opening degree signal of the gas proportional valve 7 stored in the memory circuit 1. However, if the automatic adjustment has not been completed yet, the gas proportional valve 7 enters automatic adjustment mode. gas proportional valve 7
When the adjustment mode is reached, the remote controller 3
Displays that automatic adjustment is in progress. When the combustion in the automatic adjustment mode of the gas proportional valve 7 starts, the control circuit 2 sets the initial opening degree of the gas proportional valve 7 to an opening degree that is smaller than the opening degree corresponding to the target maximum hot water output number in anticipation of the dispersion of the gas proportional valve 7. Set the input signal so that When the combustion system is stabilized, the signals from the incoming water temperature thermistor 5, outgoing hot water temperature thermistor 4, and flow rate sensor 10 are processed and converted into incoming water temperature, outgoing water temperature, and flow rate, and the difference between the outgoing water temperature and incoming water temperature is multiplied by the flow rate to determine the actual outgoing hot water. Calculate the number. The deviation between the actual number of hot water dispensed and the target maximum number of hot water dispensed is processed, and fed back to the input signal of the gas proportional valve 7, the opening degree of the gas proportional valve 7 is changed and the next hot water dispensed state is monitored. By applying feedback one after another in this way, the deviation between the target maximum number of hot water taps and the actual number of hot water taps becomes smaller. If this deviation becomes zero, the opening degree of the gas proportional valve 7 has reached the target maximum opening degree, and the value input to the gas proportional valve 7 at this time is the upper limit of the signal input to the gas proportional valve 7. It has become a value. On the other hand, a message indicating the completion of automatic adjustment is displayed on the remote controller 3. When combustion is stopped in this state, the control circuit 2 stores the input signal input to the gas proportional valve 7 in the memory circuit 1 as the upper limit value of the gas proportional valve 7. Also, from this upper limit value, the lower limit value of the input signal of the gas proportional valve 7 is calculated and stored in the memory circuit 1 in the same way as the upper limit value.
Exit automatic adjustment mode.

[Effect]

As mentioned above, in the gas proportional valve automatic adjustment mode, the maximum opening of the gas proportional valve can be adjusted by the control circuit itself without the need for trimmers or other parts, jigs, measuring instruments, etc. is possible.

[Effect of idea]

By applying the automatic adjustment mode of the present invention, special jigs, instruments, techniques, etc. are not required to adjust the gas proportional valve, making it possible to provide a low-cost and highly reliable gas water heater. can. In addition, since the gas proportional valve is adjusted while monitoring the actual number of hot water dispensed by the control circuit, the maximum number of hot water dispensed is stable and independent of the effects of the primary pressure, calorific value, thermal efficiency, etc. of the supplied gas at locations where gas water heaters are installed. is obtained.

Note that the present invention is not limited to gas water heaters, and similar effects can be obtained with water heaters that use other fuels.

[Brief explanation of drawings]

FIG. 1 shows an example of a system configuration of the present invention, and FIG. 2 shows an example of a control flow for realizing the present invention. Explanation of symbols, 1... Memory circuit, 2... Control circuit, 3... Remote controller, 4... Outgoing hot water temperature thermistor, 5... Incoming water temperature thermistor, 6... Heat exchanger, 7... Gas proportional valve, 8...Gas shutoff valve,
9... Burner, 10... Flow rate sensor, 11...
Hot water tap.

Claims (1)

[Scope of claim for utility model registration] (1) An inlet water temperature thermistor that detects the inlet water temperature at the inlet of the heat exchanger, an outlet water temperature thermistor that detects the outlet water temperature at the outlet of the heat exchanger, and the amount of water flowing into the heat exchanger. a water flow sensor that detects the gas flowing into the combustion chamber, a gas shutoff valve that opens and closes the gas flowing into the combustion chamber, a gas proportional valve that can control the gas amount, a control circuit that controls the sensor and the actuator, and a control circuit that controls the gas proportional valve. Consisting of a memory circuit that stores data and a remote controller, it processes the signals from each of the sensors mentioned above to calculate the actual hot water output number, and adjusts the opening degree of the gas proportional valve based on the deviation from the target maximum hot water output number. A gas water heater characterized by having a mechanism for learning and storing the maximum opening degree of a proportional valve. (2) The gas water heater according to claim 1, further comprising a mechanism for calculating and storing the minimum opening degree of the gas proportional valve from the maximum opening degree.