JPH04344064A - Confirming method for running water of water supply type heat exchanger - Google Patents

Abstract

PURPOSE:To effectively confirm running water without using a mechanical structure by detecting a hot water temperature of upstream and downstream water of a water supply type heat exchanger, calculating a hot water temperature rising rate, comparing it with a set value, and judging presence or absence of water passage by the compared result. CONSTITUTION:When a water supply unit such as a pump 1, etc., is operated by closing an additional combustion switch in the case of operating a bathtub having a bath boiler with a hot water supplying unit, a microcomputer 6 first detects whether outputs of inlet, outlet thermistors 3, 4 are substantially equal or not. If the thermistors 3, 4 are normal and YES is decided, a burner 5 is operated to perform an additional combustion. Then, after a predetermined time elapses, a hot water temperature rising rate is calculated based on hot water temperature and time detected by the thermistors 3, 4, and compared with a set hot water temperature rising rate. When it is the set rate or lower, a danger of no-water burning is judged, while when it is the set rate or higher, a danger of boiling of hot water is judged to stop operation of implements.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for checking the flow of water in a water-flow type heat exchanger such as a bathtub that circulates and reheats bathwater, a water heater, or a bathtub with a water heater.

0002

2. Description of the Related Art Bathtubs or water heaters that reheat bathtub water by circulation are constructed so that the equipment is operated only after confirming that water is flowing into a heat exchanger. In conventional water flow confirmation means, a magnet is attached to a door that opens and closes depending on the presence or absence of water flow, and when the door opens due to water flow, the magnet approaches a proximity switch installed outside the water flow path, causing the proximity switch to switch. A so-called water flow switch has a mechanical structure that operates the water flow, and a magnet is attached to an impeller that rotates when water flows through it.When the impeller rotates due to water flow, its rotation speed is detected by a Hall IC placed outside the flow channel. However, there is a so-called flow sensor consisting of a microcomputer and a mechanical structure that recognizes the amount of water flowing through calculation by a microcomputer control unit that also controls the heating device.

0003

[Problems to be Solved by the Invention] In the water flow switch, foreign matter may adhere to the opening/closing part of the door and cause the opening/closing part to become stuck, or foreign matter may adhere between the proximity switch and the magnet, causing water flow to be interrupted. There is a problem in that on-failures and off-failures occur in which the power remains on or off regardless of the presence or absence of the power. Further, in the flow sensor, it may become impossible to accurately detect the amount of water flowing due to a decrease in rotation due to foreign matter becoming entangled with the impeller or sticking to the impeller.

[0004] The present invention provides a method for checking water flow in a water flow type heat exchanger, which can detect the presence or absence of water flow without using any mechanical structure, in order to eliminate mechanical failures caused by foreign substances as described above. The purpose is to

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention detects the hot water temperatures on the upstream and downstream sides of a flow-through type heat exchanger, and Calculate the rate of increase in hot water temperature based on the difference in temperature and time, compare the rate of increase in hot water temperature with a preset temperature increase rate, and if the rate of increase in hot water temperature is within a certain range of set temperature increase rate. It is characterized by determining that water is flowing.

[0006]

[Function] The water temperature increase rate based on the difference between the downstream and upstream hot water temperatures and the time of the water flow heat exchanger is a nearly constant temperature determined by the equipment when there is a normal amount of water flow. Indicates the rate of increase. The present invention focuses on this point, calculates the hot water temperature increase rate based on the difference between the downstream hot water temperature and the upstream hot water temperature of the heat exchanger, and time, and compares the hot water temperature increase rate with the preset temperature increase rate. By comparison, if the hot water temperature increase rate is within a certain range of the set temperature increase rate, it is determined that water is flowing. When the hot water temperature rise rate is lower than the set temperature rise rate, it is determined that the water is not flowing and is being heated dry, and when the hot water temperature rise rate is higher than the set temperature rise rate, the flow rate has decreased due to debris clogging, etc. It is determined that there is a risk of boiling, and in either case, equipment operation is stopped.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a flowchart showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the relationship between the set temperature increase rate and the detected hot water temperature increase rate, and FIG. 3 is an example of a device to which the present invention is applied. FIG.

In FIG. 3, 1 is a pump installed in the forced circulation reheating pipe for bath water, 2 is a heat exchanger, 3 is an upstream water temperature detection sensor (hereinafter referred to as an inlet thermistor), and 4 is a heat exchanger.
is the downstream water temperature detection sensor (hereinafter referred to as the outlet thermistor)
, 5 is a combustion device, 6 is a microcomputer control unit, and 7 is a remote control. When the desired boiling water temperature is set on the remote control 7 and the reheating switch is turned on, the microcomputer control unit 6 drives the pump 1 to start the bathtub. Water is circulated, the bathtub water temperature is detected by an inlet thermistor 3, and when the bathtub water temperature is lower than the set water temperature, the combustion device 5 is combusted by the microcomputer control unit 6 to operate until the set water temperature is reached. It is composed of In the present invention, an outlet thermistor 4 is also provided on the downstream side of the heat exchanger, and the inlet thermistor 3 and outlet thermistor 4 detect the upstream and downstream hot water temperatures, respectively, as described below. Check the running water.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[0011] The rate of increase in hot water temperature based on the difference between the downstream and upstream hot water temperatures of a water flow type heat exchanger and time is a nearly constant temperature rise determined by the equipment when there is a normal amount of water flow. Show rate. In the present invention, this normal temperature increase rate (shown in FIG. 2) is stored in the microcomputer control section 6. A specific method is, for example, to detect the rate of temperature rise during the first operation when the appliance is installed, and to store the temperature increase rate with a certain range in the microcomputer control unit. Alternatively, when mass producing a specific device, a temperature rise rate within a certain range is stored from the time of shipment.

As shown in FIG. 1, when the reheating switch is turned on, the water flow equipment such as the pump 1 is activated, and then,
Confirm that there is no open short circuit between the inlet thermistor 3 and the outlet thermistor 4, and then
It is detected whether the output of the output thermistor 4 and the output of the outlet thermistor 4 are substantially equal. This is an initial check to see if the thermistor is normal, and if it is abnormal, the abnormality is displayed on the remote controller 7 without performing a heating operation. If normal,
After confirming that the output of the inlet thermistor 3 is lower than the set temperature set on the remote control, the combustion device 5 is activated to perform reheating operation, and x seconds (for example, 5 to 10
seconds), the water temperature detected by the inlet thermistor 3 and the outlet thermistor 4 and the water temperature rise rate based on the time are calculated by the microcomputer control unit 6, and the water temperature rise rate is stored in the microcomputer control unit. Compared to the temperature rise rate,
If it is normal, the reheating operation continues, and when it is detected that the set hot water temperature has been reached, the pump 1 and the combustion device 5 are stopped to end the reheating operation.

[0013] If the detected hot water temperature increase rate is lower than the set temperature increase rate and is in the area A of Fig. 2, the temperature will not increase in a certain period of time despite heating, so the It is determined that the fire is on, the operation of the appliance is stopped, and this state is displayed on the remote control 7. In addition, if the detected water temperature increase rate is higher than the set temperature increase rate and falls in area B in Figure 2, it is determined that there is a risk of boiling due to a decrease in flow rate due to debris clogging or pump failure, and the equipment is stopped. and displays this state on the remote control 7.

[0014] In the above embodiment, the present invention is applied to a forced circulation type reheating device, but the present invention is not limited to this embodiment. It can be applied directly to the bath kettle.

[0015]

[Effects of the Invention] As described above, according to the present invention, it is possible to check flowing water without using any mechanical structures, so cost reduction is achieved by eliminating the need for mechanical structures. In addition, there is an effect that mechanical failures caused by foreign objects or the like can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the relationship between a set temperature increase rate and a detected hot water temperature increase rate.

FIG. 3 is a configuration diagram showing an example of a device to which the present invention is applied.

[Explanation of symbols]

1...Pump, 2...Heat exchanger, 3...Inlet thermistor, 4...
Outlet thermistor, 5... combustion device, 6... microcomputer control unit,
7...Remote control.

Claims (2)

[Claims] 1. Detecting the hot water temperatures on the upstream and downstream sides of a flow-through heat exchanger, and calculating the rate of increase in hot water temperature based on the difference between the downstream and upstream hot water temperatures and time, A flow-through type heat exchanger that compares the hot water temperature increase rate with a preset temperature increase rate, and determines that water is flowing if the hot water temperature increase rate is within a certain range of the set temperature increase rate. How to check running water. 2. Detecting the hot water temperatures on the upstream and downstream sides of the water flow heat exchanger, and calculating the rate of increase in hot water temperature based on the difference between the downstream and upstream hot water temperatures and time, The rate of increase in hot water temperature is compared with the preset rate of increase in temperature, and if the rate of increase in hot water temperature is within a certain range of the set temperature increase rate, it is determined that water is flowing and the appliance continues to operate, causing the hot water temperature to rise. When the water temperature rise rate is below a certain range of set temperature rise rate, it is judged as dry heating, and when the water temperature rise rate is above a certain range of set temperature rise rate, it is judged that there is a risk of boiling due to a decrease in flow rate due to garbage clogging etc. , a method for controlling the operation of a water heating device, characterized in that the operation of the device is stopped in either case.