JPH04177047A - Flow rate sensing method, flow rate controlling method and flow rate sensing device in additional boiling circulation circuit - Google Patents

Abstract

PURPOSE:To enable a circulating flow rate to be assumed by a method wherein a relation between a flow rate and a temperature difference is calculated in advance while the flow rate is being varied when a hot water is fed to a bath tub and a temperature difference across a heat exchanger when a pump is driven to perform an additional boiling and circulation is detected. CONSTITUTION:As water of more than a predetermined volume is flowed to an additional boiling heat exchanger 3, a water flow sensor 7 detects it, a combustion device 14 is ignited and then combustion is started. After waiting a predetermined period of time until a flow rate of hot water passing through an additional boiling heat exchanger 3 and an increased amount of temperature caused by the additional boiling heat exchanger is stabled, a flow rate Q is detected by a flow rate sensor 13 and at the same time a temperature difference of hot water before and after passing through the additional boiling heat exchanger 3 is detected by temperature sensors 10 and 11. Then, the flow rate just detected and the temperature difference are stored. The temperature difference across the addition boiling heat exchanger 3 is detected and the temperature difference is given to an address input of RAM storing the map of the relation between the temperature difference and the flow rate in reference to the data of the detected temperature difference and the data showing a relation between the previous stored temperature difference and the flow rate, thereby data of the circulating flow rate can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flow rate detection method, a flow rate control method, and a flow rate detection device in a reheating circulation circuit in a bathtub.

[Prior Art] Japanese Utility Model Application Publication No. 2-41053 discloses, as shown in FIG. 7, a pump 2 for forcibly circulating hot water in a bathtub 1 and a heat exchanger 3.
A technique has been disclosed in which a flow rate sensor 4 is installed in a reheating circulation circuit equipped with a reheating circuit, and the capacity of the pump 2 is limited based on the circulation flow rate directly detected by the flow rate sensor 4. The reason for this restriction is that the capacity of pump 2 is usually set to be large.
This is because if the pipe is operated at full capacity, the flow velocity in the circulation circuit will become too high, which may cause corrosion at bends in the pipe, at joints, and on the downstream side where the pipe diameter changes.

[Problems to be Solved by the Invention] By the way, if the reheating circulation circuit is equipped with a flow rate sensor as described above, there is a risk that the flow rate sensor will not operate correctly due to clogging.

Therefore, the present invention provides a flow rate detection method that can determine the circulating flow rate without installing a flow rate sensor in the reheating circulation circuit, a method of controlling the circulating flow rate according to the detection result, and a device that detects the flow rate. The purpose is to provide.

[Means for Solving the Problems] The method for detecting the flow rate of a reheating circulation circuit according to the invention of claim 1 is as follows: Water from a water supply pipe is supplied to a bathtub through a reheating heat exchanger that adds a constant amount of heat per hour. At that time, since the flow rate is not changed, the first step is to detect the temperature difference between the hot water before and after passing through the reheating heat exchanger to obtain data showing the relationship between the flow rate and the temperature difference, and Hot water is circulated through the reheating heat exchanger using a pump, and the temperature difference between the hot water before and after passing through the reheating heat exchanger, which is operated under the same conditions as above, is detected, and the detected temperature difference and the above-mentioned temperature difference are detected. A second step of determining the circulation flow rate by the pump based on the data obtained in the first step.

Further, the flow rate control method of the reheating circulation circuit according to the invention of claim 2 adjusts the flow rate of the reheating circulation circuit by controlling the pump based on the flow rate determined by the flow rate detection method according to claim 1. It is characterized by

Further, the flow rate detection device according to the invention of claim 3, as shown in FIG. and (b) a reheating heating device 52 that heats the reheating heat exchanger; a variable flow rate water supply valve 53 that communicates and cuts off the CC>reheating circulation circuit and the water supply pipe; and (d) in the closed position. an on-off valve 54 that controls water from the water supply pipe to flow into the bathtub through the reheating heat exchanger when operated; and (e) controlling the temperature difference between the hot water before and after passing through the reheating heat exchanger. (f) a flow rate detection means 56 installed in the water supply pipe; (g) opening the water supply valve 53 and closing the on-off valve 54; a hot water filling control section 57 that controls the water supply flow rate at a constant level and adjusts the opening degree of the water supply valve 53 to change the water supply flow rate; (h) detection by the flow rate detection means 56 during the control operation by the hot water filling control section 57; map creation means 58 for reading the value and the detection value of the temperature difference detection means 55 and storing the relationship between the two as a map;
(1) A prostitute control section 59 that closes the water supply valve 53 and opens the on-off valve 54 to drive the pump 51, and at this time manages the heating amount of the prostitute heating device 52 to a constant state similar to the above, (j ) A flow rate calculation means 60 that reads the detected value of the temperature difference detection means 55 during the control operation by the prostitute control section 59 and calculates the circulating flow rate from the detected value and the data stored in the map creation means 58; It is characterized by having the following.

[Function] When the amount of heat added to the prostitute heat exchanger is controlled to be constant per hour, there is a constant difference between the flow rate of hot water passing through the heat exchanger and the temperature difference (increase in temperature) of hot water before and after the heat exchanger. The relationship holds true. Therefore, by changing the flow rate and understanding the relationship between the flow rate and the temperature difference, conversely, if the temperature difference is known, the flow rate at that time can be estimated based on that value.

The present invention applies this principle, and since the flow rate is not changed when filling the bathtub with hot water, the relationship between the flow rate and the temperature difference is determined. Then, by detecting the temperature difference before and after the heat exchanger when the pump is driven to circulate the prostitute, the circulation flow rate at that time is estimated. By doing so, it is possible to know the circulation flow rate without providing a flow rate sensor in the prostitute circulation circuit.

[Example] Hereinafter, an example in which the flow rate detection device for a prostitute circulation circuit of the present invention is applied to a fully automatic bath pot will be described with reference to FIGS. 2 to 6. Note that the flow rate detection method and flow rate control method of the present invention will be implemented during the control operation of this device.

Figure 2 shows the schematic configuration of the bathtub, in which 1 is the bathtub, 2
is a pump, and 3 is a prostitute heat exchanger. Focusing on the pump 2, one circulation port 1a provided in the bathtub 1 is connected to the suction side of the pump 2 via a return pipe 5, and the other circulation port 1b of the bathtub 1 is connected via an outflow pipe 6. It is connected to the discharge side of the pump 2.

A prostitute heat exchanger 3 is inserted in the middle of the outgoing pipe 6, thereby forming a prostitute circulation circuit J that circulates hot water in the bathtub 1 via the prostitute heat exchanger 3. In addition, between the heat exchanger 3 and the pump 2, a flowing water sensor 7 and a prostitute return valve (opening/closing valve) 8 are inserted in order from the heat exchanger 3 side. The tip of a water supply pipe 9 is connected to the outgoing pipe 6 in between. The flowing water sensor 7 detects whether water is flowing through the heat exchanger 3 or not. Also,
The prostitute return valve 8 controls all water from the water supply pipe 9 to flow into the bathtub 1 through the heat exchanger 3 when in the closed position.

Furthermore, a human-side tolerance sensor 10 and an outlet-side temperature sensor 11 are provided at the inlet and outlet of the heat exchanger 3, respectively, and the water supply pipe 9
A water supply valve 12 with variable flow rate and a flow rate sensor 13 are provided. Note that the water supply valve 12 and the return valve 8 are composed of electromagnetic valves. Further, the prostitute heat exchanger 3 is attached with a combustion device 14 consisting of a heating burner.

Next, we will discuss the control system. As shown in FIG. 3, each detection signal of the flow rate sensor 13, flowing water sensor 7, inlet temperature sensor 10, and outlet temperature sensor 11 is input to the control device 20, and the automatic Operation signals from the switch 22, temperature setting device 23, and water amount setting device 24 are input. Then, the control device 20
Based on these input signals, the combustion device 14, the pump 2
, controls the operations of the prostitute return valve 8 and the water supply valve 12.

The control device 20 is mainly composed of a microcomputer, and also includes an input/output device, an A/D converter, a multiplexer, and a drive circuit for the combustion device 14, the pump 2, the prostitute return valve 8, and the water supply valve 12. etc.

This control device 12 is characterized in that a microcomputer executes processing in accordance with the procedure shown in FIG. The contents of automatic operation by the control device 20 will be explained below while referring to the flowchart of FIG.

When the power is turned on, the microcomputer performs initial settings and enters a standby position. From this state, the hot water filling temperature and hot water filling amount (water level) are controlled by the remote control device 21.
and turn on the automatic switch 22. Then,
The microconference process proceeds according to the flow shown in Figure 4.

First, in the first step 101, close the prostitute return valve 8,
In the next step 102, the water supply valve 12 is opened.

At this time, the opening degree θ of the water supply valve 12 is a predetermined initial value θ. (It does not need to be so small as long as it is at least enough to operate the combustion device 14).

Then, all the water from the water supply pipe 9 is connected to the prostitute heat exchanger 3.
It flows into the bathtub 1 through it.

Then, when more than a predetermined amount of water flows into the prostitute heat exchanger 3,
The flowing water sensor 7 detects this, and the combustion device 14 ignites based on the detection signal and starts combustion (step 10
3). At this time, the opening degree of the gas supply valve of the burner is kept constant to control the heating amount per time to be constant.

Then, wait for a predetermined time until the flow rate of the hot water passing through the prostitute heat exchanger 3 and the amount of temperature rise due to the heat exchanger 3 are stabilized (step 104), and detect the flow rate Q with the flow rate sensor 13 (step 104). 105), the temperature difference (T-T'') between the hot water before and after passing through the prostitute heat exchanger 3 is detected by the temperature sensor 10.11 (step 10).
6).

Next, the flow rate Q and the temperature difference (T-T'') that have just been detected are stored.For example, the temperature difference (T-T') can be stored.
) is used as an address, and the digitally converted value of the flow rate Q is stored in the contents of the RAM.

While the detected flow rate Q is smaller than the preset maximum flow rate QMAX (preferably a value somewhat larger than the allowable maximum flow rate QV, which will be described later), the determination in step 108 is NO, and the opening degree θ of the water supply valve 12 is changed. Gradually increase the thickness by Δθ (step 109), steps 104 to 1
Repeat the process of 07. As a result, data showing the relationship between the flow rate and the temperature difference is sequentially accumulated in the storage device according to changes in the flow rate, and a map is created.

The collected data is shown in FIG.

In other words, the larger the flow rate Q, the greater the temperature difference (T-
T') becomes small, and the relationship between the flow rate and the temperature difference becomes proportional. Then, when the detected flow rate Q becomes equal to or higher than the predetermined maximum flow rate QWAX, the determination in step 108 becomes YES, and the above-described data collection and storage work is completed.

Next, the process proceeds to step 110, and when the set amount of water has been supplied, the determination in step 110 becomes YES, the combustion is stopped (step 111), and the water supply valve 12 is closed (step 112). Up to this stage, hot water filling has been controlled, and at the end of this hot water filling, the bathtub water temperature is lower than the set temperature. In other words, the amount of heat generated by the burner is managed to achieve this. Next, we move on to prostitute control.

After closing the water supply valve 12, proceed to step 113 and open the prostitute return valve 8 (then turn on the pump 2 and proceed to step 1).
14) The hot water in the bathtub 1 is forced to circulate within the prostitute circulation circuit. At this time, the first applied voltage V to the pump 2 is set to a predetermined initial value V0 (a relatively small value). When hot water in the bathtub circulates in the circulation circuit, the flowing water sensor 7 detects this, and the combustion device 14 starts operating based on the detection signal (step 115). The amount of heat generated at this time is
Control so that it is exactly the same as when filling the hot water above.

Then, in step 116, the temperature difference (T-T') after cutting of the prostitute heat exchanger 3 is detected, and in step 117, the data of the temperature difference (T-T') just detected and the previously stored data are detected. The current circulating flow rate Q is calculated from data indicating the relationship between the temperature difference and the flow rate. Specifically, for example, by applying a temperature difference (T-T'') to the address input of a RAM that stores a map of the relationship between temperature difference and flow rate, the output of flow IQE data is obtained.

Next, in step 118, it is determined whether the calculated flow rate QE is greater than or equal to the maximum allowable flow rate 08. Here, the maximum allowable flow rate Q
Let's talk about K. As mentioned in the section on the prior art, if the flow velocity in the circulation circuit becomes too high, corrosion may occur in some places in the pipes. Therefore, the maximum flow rate without the risk of corrosion is determined from the maximum flow rate without the risk of corrosion and the cross-sectional area of the minimum diameter portion of the pipe. This is defined in advance as the allowable maximum flow rate Q.

The applied voltage V of the pump 2 is gradually increased by ΔV until the calculated flow rate Q2 reaches the maximum allowable flow rate Q8 (step
7p119). Then, each time, the temperature difference (T-T") before and after the prostitute heat exchanger 3 is detected, and the circulating flow rate Q2 is calculated. When the calculated flow rate QE reaches the allowable maximum flow rate Q1, the judgment in step 118 is YES. Therefore, the voltage of the pump 2 is left unchanged and the process proceeds to step 120.

In this step 120, the current pump voltage V is changed to VDN
Store as AX. The circulation flow rate is approximately proportional to the pump voltage, provided that the installation conditions do not change, that is, if the prostitute circulation is performed in the same bath pot and at approximately the same water level. Therefore, remember the pump voltage that will give you the maximum allowable flow rate (
(By doing so, the pump voltage will be set to VD from the next automatic operation)
Once set to IAI, hot water can be circulated at the maximum allowable flow rate. Therefore, this step 1
At step 20, VD□8 is stored. Note that this step 120 may be omitted depending on the method of processing from next time onwards.

Then, the prostitute continues without circulating the hot water in the bathtub 1 at the allowable maximum flow rate Q, and when the detected hot water temperature T' reaches the set temperature T0, the judgment in step 121 becomes YES and the process proceeds to step 122. Then, combustion by the combustion device 14 is stopped, the pump 2 is set to 0FF1 (step 123), the prostitute return valve 8 is closed (step 124), and the current process is ended.

The next automatic operation may be performed using the same process as described above. However, it may also be done as shown in FIG. FIG. 5 shows the flow of the second and subsequent processes when ^X is stored in vD in the first process.

In this case, when the automatic switch is turned on, the prostitute return valve 8 is closed in the first step 201, and the water supply valve 12 is opened in the next step 202. Q. If the value is less than or equal to Q, it may be fixed arbitrarily. When water flows into the prostitute heat exchanger 3, the water flow switch 7 detects this and starts combustion (switch 203). At this time, the combustion device 14 is controlled so that the outlet hot water temperature, that is, the detected value T of the outlet temperature sensor 11, is equal to the set temperature T0 set by the remote control device 21, and the temperature T is set. hot water is supplied to the bathtub 1.

When the set amount of water is reached, the determination in step 204 is YES, the combustion is stopped (step 205), and the water supply valve 12 is closed (step 206). This means that the hot water filling is completed. Next, in order to check the temperature of the water in the bathtub 1, the prostitute return valve 8 is opened (step 207), the pump 2 is turned on (step 208), the hot water in the bathtub 1 is forcibly circulated in the prostitute circulation circuit, and the state is The temperature of the water in bathtub l is detected (step 209). That is, the detected value T' of the inlet temperature sensor lO is read.

During this forced circulation, the voltage V applied to the pump 2 is set to the previously stored VDNAX. By doing so, forced circulation can be performed making maximum use of the pump capacity without causing corrosion.

As a result of detecting the bathtub water temperature T°, the water temperature T' is the set temperature T0.
If the value has not been reached, the determination in step 210 is YES.
Then, the process goes to steps 211 and 212, where the hot water temperature T' becomes the set temperature T. Perform prostitute combustion until When the set temperature is reached, the combustion is stopped (step 213), the pump 2 is turned off, the prostitute return valve 8 is closed, and the process ends.

Also, if the water temperature T' has reached the set temperature T0 at the time of filling the water, the judgment in step 210 will be No, and the process will proceed to step 214 without performing the prostitute operation, and the pump 2 will be turned off.
L, close the prostitute return valve 8 and end the process.

In this way, once the pump voltage VDMAX for obtaining the maximum allowable flow rate Q3 is known, the pump applied voltage will be set to that voltage V from the next time. By setting WAX, the circulation flow rate can be automatically controlled to the maximum allowable flow rate.

Therefore, automatic operation can be easily realized in a state where the pump capacity is utilized to the maximum without fear of corrosion.

Note that the control operation is of course not limited to the above embodiment.

In addition, in the above embodiment, the water supply valve 12 and the flow rate sensor 13r are provided separately, but if a water supply valve that can accurately control the flow rate according to the set flow rate is used, the set flow rate can be directly adjusted to the detected flow rate (actual flow rate). ) can also be treated as Therefore, in that case, there is no need to separately provide a flow rate detection means, and the set flow rate signal may simply be treated as the detected flow rate signal for control purposes.

Furthermore, in the above embodiments, a gas-type combustion device is shown as the heating device, but it is of course possible to use an oil-type combustion device or an electric heating device.

[Effects of the Invention] As explained above, according to the present invention, the flow rate in the prostitute circulation circuit can be detected without installing a flow rate sensor in the circulation circuit, and the flow rate can be adjusted to a predetermined value. can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a flow rate detection device according to the present invention, and FIGS. 2 to 6 are explanatory diagrams of an embodiment of the present invention.
Fig. 2 is a piping system diagram showing the configuration of a bathtub to which the present invention is applied, Fig. 3 is a control system diagram of the bathtub, Fig. 4 is a flowchart showing the details of automatic operation of the bathtub, and Fig. 5 6 is a flowchart showing the content of automatic operation from the second time onward, FIG. 6 is a diagram showing steps for determining the circulating flow rate of the bathtub, and FIG. 7 is a configuration diagram of a conventional bathtub. 1... Bathtub, 2,51... Pump, 3 - Prostitute heat exchanger, 7... Flowing water sensor, 8... Prostitute return valve (on/off valve), 9... Water supply pipe, 10... Inlet temperature sensor, 11... Outlet temperature sensor, 12.53...
... Water supply valve, 13 ... Flow rate sensor (flow rate detection means), 14 ... Combustion device (prostitute heating device), 2
0... Control device, 52... Prostitute heating device, 54
...Opening/closing valve, 55...Temperature difference detection means, 56
...Flow rate detection means, 57...Hot water filling control section,
58...Map creation means, 59...Prostitute control section, 60...Flow rate calculation means.

Claims (3)

[Claims] (1) Water from the water supply pipe is supplied to the bathtub through a reheating heat exchanger that adds a fixed amount of heat per hour, and the flow rate is varied before and after the hot water passes through the reheating heat exchanger. The first step is to detect the temperature difference and obtain data showing the relationship between the flow rate and the temperature difference, and the hot water in the bathtub is circulated by a pump via the reheating heat exchanger, which is operated under the same conditions as above. a second step of detecting the temperature difference between the hot water before and after passing through the reheating heat exchanger, and calculating the circulating flow rate by the pump based on the detected temperature difference and the data obtained in the first step; How to detect flow rate in reheating circulation circuit. (2) A flow rate control method for a reheating circulation circuit, which adjusts the flow rate of the reheating circulation circuit by controlling the pump based on the flow rate determined by the flow rate detection method according to claim 1. (3) (a) a pump provided in the reheating circulation circuit that circulates hot water in the bathtub via the reheating heat exchanger; (b) a reheating heating device that heats the reheating heat exchanger; (c) A variable flow rate water supply valve that communicates and shuts off the reheating circulation circuit and the water supply pipe; (d) When the water supply pipe is operated to the closed position, all water from the water supply pipe flows into the bathtub through the reheating heat exchanger. (e) a means for detecting the temperature difference between the hot water before and after passing through the reheating heat exchanger; (f) a flow rate detecting means installed in the water supply pipe; (g) the above. a hot water filling control unit that opens a water supply valve and closes an on-off valve, manages the heating amount of the additional heating device at a constant level, and adjusts the opening degree of the water supply valve to change the water supply flow rate; ) map creation means for reading the detection value of the flow rate detection means and the detection value of the temperature difference detection means during the control operation by the hot water filling control section and storing the relationship between the two as a map; (i) the water supply valve; a reheating control section that closes the on-off valve and drives the pump by opening the on-off valve, and at this time manages the heating amount of the reheating heating device to a constant state similar to the above; (j) control operation by this reheating control section; A flow rate calculating means for reading the detected value of the temperature difference detecting means and calculating the circulating flow rate from the detected value and the data stored in the map creating means. Flow rate detection device for firing circulation circuit.