JPH04211780A - Hot and cold water mixing type hot water supply device - Google Patents

Abstract

PURPOSE:To provide a safe hot and cold water mixing type hot water supply device which uses a mixing valve for mixing hot and cold water so as to have a suitable temperature and which prevents supply of hot water having a temperature different from a set temperature and overshooting of mixed hot water. CONSTITUTION:A drive device for driving a mixing valve body is started and stopped in response to a start and a stop of supply of mixed hot water with the use of a hot water faucet 37, a thermistor 55 provided upstream of the hot water faucet 37 and a flow switch 59. Further, occurrence of supply of hot water from a mixing valve body can be prevented even upon resupply after stopping of hot water, and erroneous recognition of a detected temperature by the thermistor can be eliminated, thereby it is possible to prevent overshooting from increasing.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater equipped with a mixing valve for mixing hot water and water, and more particularly to a structure for safely supplying hot water.

0002

[Prior Art] Conventionally, this type of hot water mixing type water heater has the following features:
There were some as shown in Figures 3 and 4. That is, in FIG. 3, water supplied from a water supply 1 is heated by a heater 3 in an electric water heater 2, which is a hot water supply heat source, and is stored in a tank 4. A hot water supply pipe 5 is connected to the electric water heater 2, and manual hot water mixing taps 6 and 7 are provided at the ends of the hot water supply pipe 5 as hot water taps. This hot water mixing faucet 6,7
There are hot water supply branch pipes 8 and 9 that branch from the hot water supply pipes, respectively, and a water supply pipe 10 that branches from the water supply 1 in front of the electric water heater 2.
Water supply branch pipes 11 and 12 are connected to the water supply branch pipes 11 and 12. When the hot water mixing faucet 6 or 7 is opened, the electric water heater 2
The high temperature hot water stored in the tank 4 inside is pushed by the water pressure of the water supply 1 and passes through the hot water supply pipe 5 to reach the hot water mixing faucet 6 or 7. Here, the hot water is mixed with water from the water supply pipes, cooled down to a temperature suitable for use, and then supplied.

FIG. 4 shows a hot water mixing faucet 6 or 7, and the main body 13 has a hot water inlet 14 and a water inlet 15, and a hot water flow path 16 and a water flow path 17 are separated by valves. The opening degree is adjusted by a slit 18 provided in the body 19. The valve body 19 operates to slide vertically in the figure, and is driven by a wax pellet 20 that also serves as a mixed water temperature detection means, and when the mixed water temperature rises above the temperature set with the temperature control knob 21, When the wax pellet 20 expands, it moves the valve body 19 upward, and when it falls, it moves downward to adjust the opening degree of the flow path. Mixed hot water is mixed hot water flow path 2
2 or 22', for example, a hot water tap 23 to the bath.
Alternatively, hot water is supplied to the target by opening and closing the hot water tap 24 to the shower. When both the hot water taps 23 and 24 are closed and hot water supply stops, the water temperature decreases due to natural heat radiation, so the wax pellet 20 contracts and the valve body 19 is pushed by the spring 25 and moves downward, reducing the flow on the water side. The slit 18 gradually narrows the path 17. When the hot water has completely cooled down, the water side flow path 17 is completely closed and the hot water side flow path 16 is fully opened. In this conventional example, the valve body is driven by a wax pellet that also serves as a mixed water temperature detection means, but in recent years there has also been a method in which the valve body is driven by a motor and the mixed water temperature is detected and controlled using a thermistor. However, as the hot water cools after hot water supply is stopped, the phenomenon in which the valve body opens the hot water side flow path and closes the water side flow path is similar to the wax pellet type. I was awake.

0004

[Problems to be Solved by the Invention] Conventionally, this type of hot water mixing device has been constructed as described above, and has had the following problems.

(1) Because the valve body closes the water side flow path and opens the hot water side flow path due to natural heat radiation cooling after hot water supply is used, when hot water supply is restarted, hot water higher than the set value is supplied. There is a risk of burns. Especially after other hot and cold water mixing faucets nearby have been used, in a circulating hot water system, or in cases where the hot water piping distance to the hot water supply heat source is short, very hot water may come out because less heat is absorbed by the hot water piping. It is a danger.

(2) Since temperature control always starts with the hot water side flow path open and the water side flow path closed, it takes time to reach the set temperature.

(3) When the driving means is an electric type, electricity is supplied to move the valve body even during cooling after the hot water supply is stopped, which is contrary to energy saving.

[0008] The present invention is intended to solve these conventional problems, and aims to provide a safe hot water mixing type water heater that prevents the supply of hot water or hot water at a temperature different from the set temperature.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the hot and cold water mixing type water heater of the present invention has a valve body and adjusts the opening degrees of the hot water side flow path and the water side flow path within the valve body. a mixing valve body, a driving device that drives the mixing valve body, a temperature setting device for the mixed water temperature, a flow control valve provided in the mixing water flow path, and a temperature detection device provided upstream of the flow control valve. A flow detector, which is also provided on the upstream side and directly or indirectly detects the supply state of the mixed hot water, compares the signals from the temperature setting device and the temperature detector to control the drive device. , and a controller that starts and stops the drive device in response to the supply and stop state of mixed hot water.

0010

[Operation] According to the above-described structure, the mixing valve element drive device is stopped when hot water supply is stopped, and as the ambient temperature of the temperature sensor naturally radiates heat, the mixing valve element opens the hot water side and opens the water side. This prevents the phenomenon of closing and eliminates the need to supply hot water when refilling hot water.

[0011] Furthermore, by providing the temperature sensor upstream of the flow rate control valve, the temperature sensor is not exposed to air that enters the downstream side of the flow rate control valve when hot water supply is stopped, and the mixed hot water during reheating is prevented. This reduces errors in mixed water temperature detection due to temperature misrecognition and scale adhesion, and prevents transient overshoots of the mixed water.

Furthermore, by providing the flow detection means on the upstream side of the flow rate control valve or by using a method of indirect detection, malfunctions due to the presence of air or scale adhesion can be prevented, and when hot water supply is started or stopped, This is to reliably start and stop the drive device.

[0013]

[Embodiment] Next, an embodiment of the present invention will be explained based on FIGS. 1 and 2. In FIG. 1, water supplied from a water supply 31 is supplied to a heater 3 in an electric water heater 32, which is a hot water supply heat source.
3 and stored in a tank 34. A hot water supply pipe 35 is connected to the electric water heater 32, and hot water mixing devices 36, 36' and hot water taps 37, 37', which are flow rate control valves, are provided on the terminal side of the hot water pipe 35.

To explain the hot water mixing device 36 as a representative example, as shown in FIG.
Valve bodies 44 and 45 are provided to adjust the opening degree of the water side flow path 43.

The water side valve body 45 has a piston 46 for pressure balance, and although not shown in the drawings, the pressure in the mixing chamber 47 is guided to a chamber 48 on the back side of the piston 46. A shaft 49 passes through the valve bodies 44 and 45, and the valve bodies 44 and 45 can slide on the shaft 49.

The valve bodies 44 and 45 are urged outward by a spring 50, and their outermost ends are regulated by stop shafts 51 and 52 provided on the shafts. The shaft 49 is driven by a motor 53, which is an electrical drive device, via a conversion device 54 provided outside the valve body 41 that converts rotation into sliding. The mixed water temperature is detected by a thermistor 55, which is a temperature detector provided upstream of the hot water tap 37, and a controller 56 compares the signals of the thermistor 55 and the temperature setting device 57.
The amount of drive of the valve bodies 44, 45 by the motor 53 is determined according to the deviation, and the mixed water temperature is controlled. Mixing channel 58
A switch 59 is installed on the upstream side of the hot water tap 37 as a flow detector that directly detects the supply state of the mixed hot water. The motor 53 is started and stopped.

Next, the operation will be explained. Assume that hot water is being supplied by opening and closing the hot water tap 37. electric water heater 32
The hot water inside passes through the hot water supply pipe 35 at tap pressure and is supplied to the hot water mixing device 3.
Sent to 6. Water sent through the water supply pipe is also introduced into the hot water mixing device 36. The opening degrees of hot water and water passages 42 and 43 are adjusted by valve bodies 44 and 45, and the flow rates of the hot water and water coming in from the hot water inlet 38 and the water inlet 39 are determined. The valve bodies 44 and 45 are controlled by a signal deviation from a thermistor 55 and a temperature setting device 57, and when the mixed hot water temperature picked up by the thermistor 55 is higher than the set value, the motor 53 is driven via the controller 56. Push the shaft 49 to the right via the converter 54. This causes the valve bodies 44 and 45 to move in parallel, with the valve body 44 moving in the direction of closing the hot water side flow path 42 and the valve body 46 moving in the direction of opening the water side flow path. When the mixed hot water temperature is lower than the set value, the valve bodies 44 and 45 move to open the hot water side flow path 42 and close the water side flow path 43. While hot water is being supplied, since there is a flow in the mixed hot water channel 58, the flow rate switch 59 remains on to ensure that the motor 53 is energized. During hot water supply, if the flow rate changes due to fluctuations in hot water or water pressure, the mixed water temperature will change as a result, but this will be fed back to the motor 53 by the thermistor 55 and the controller, and the valve will be activated to return to the original set value. Bodies 44 and 45 are driven.

Since hot water supply becomes unnecessary and the flow stops when the hot water supply faucet 37 is closed, the flow rate switch 59 is turned off and at least the power to the motor 53 is cut off. Even if the water temperature around the thermistor 55 falls due to natural heat radiation, the motor 53 does not move, so power is not consumed as in the conventional system, and the valve bodies 44 and 45 are in the position immediately before hot water supply is stopped. It's coming. Next, it is assumed that hot water supply becomes necessary again and the hot water tap 37 is opened. Since the valve bodies 44 and 45 are in the position when the hot water supply was stopped last time, even if hot water flows in from the hot water side flow path 42, the previous hot water temperature setting does not indicate the maximum hot water temperature. As far as possible, the hot water side flow path 42 is in a constricted state, and mixed hot water equal to or lower than the previous time is supplied. In addition, even if the temperature setting is changed from the previous hot water supply to a higher or lower temperature, the valve bodies 44 and 45 do not have to start controlling the flow path to open and close the flow path from the fully open state of the hot water side, as in the conventional case. . Furthermore, since the hot water supply faucet 37 is provided in the mixing flow path, even if it should fail, only the hot water side would be opened and hot water would not be supplied, which would happen if they were provided independently on the hot water side and water side.

[0019] Normally, the temperature of the hot water supply will vary depending on the season and where it is used, such as the bath or kitchen, but it is rare to change the temperature setting each time with one hot water tap, and the temperature will be the same as the previous one. In many cases, the set temperature remains the same.

When hot water supply is stopped, the flow rate switch 59
Since both the thermistor 55 and the thermistor 55 are provided upstream of the hot water tap 37, which is a flow rate control valve, the mixed hot water from the hot water tap 37 onwards falls from the outlet and is filled with air, which removes the scale contained in the mixed hot water. Components do not dry, stick, or stack. This eliminates malfunction of the flow rate switch 59 and erroneous recognition of the temperature of the thermistor 55. In particular, if scale is stacked on the surface of the thermistor 55, even if the mixed water temperature overshoots due to disturbance, detection will be slow, and the operation of the mixing valve to return the mixed water to its original state will be delayed, resulting in dangerous high-temperature water. However, the configuration of the present invention can prevent this.

Furthermore, a thermistor 5 is installed downstream of the hot water tap 37.
5, the thermistor 55 would detect the temperature of the air that entered when hot water supply was stopped. Normally, the air temperature is mostly lower than the temperature of the mixed water used for hot water supply, and in the case of mixed hot water, the heat capacity is large, so the temperature drop due to natural heat radiation is slow, and the hot water in the hot water supply pipe 35 is It is related to cooling. Therefore, when the hot water supply is restarted in a relatively short time after the hot water supply is stopped, the thermistor 55
From the point where the temperature is lower than the temperature on the upstream side of the
Since the hot water side is temporarily opened and the water side is closed, there is a drawback that overshoot becomes large, but the configuration of the present invention can prevent this problem.

In the above embodiment, the flow of mixed hot water is detected by the flow rate switch provided upstream of the hot water tap 37, so the usage status of the hot water supply can be detected even if there are a plurality of hot water taps.

In addition to the flow rate switch, a flow detector for detecting the supply state of mixed hot water is, for example, integrated with a hot water tap, the switch is turned on and off in conjunction with the operation of the hot water tap, and this on/off signal is sent to a controller using an electric wire. indirect methods of communicating with
One possible method is to use a pressure switch to pick up pressure fluctuations caused by opening and closing the hot water tap.

[0024]

[Effects of the Invention] As explained above, the hot water/cold water mixing type water heater of the present invention uses a flow detector that directly or indirectly detects the supply state of mixed hot water, and responds to the supply/stop state of mixed hot water. At the same time, a temperature sensor is installed upstream of the flow control valve, and a flow sensor is installed upstream of the flow control valve as a type that can directly detect the supply status of mixed hot water, or it can be installed indirectly. Since the flow state can be detected visually, it has the following effects. (1) When the supply of mixed hot water is stopped, it is possible to prevent the phenomenon in which the mixing valve opens the hot water side and closes the water side due to natural cooling, so it is safe and prevents the phenomenon that hot water is supplied when the supply resumes. This also makes it possible to shorten the time it takes to reach the set temperature and save energy for the drive device. (2) Since the temperature sensor is installed upstream of the flow rate control valve, mixed hot water is always present around the temperature sensor when hot water supply is stopped, and air is present when the temperature sensor is installed downstream. It is safe because there is no need to supply hot water when restarting hot water supply due to misrecognition of the detected temperature that occurs, and no increase in overshoot due to response deterioration caused by accumulation of scale components in the mixed hot water on the temperature sensor. (3) A flow detector that directly detects the flow state of the mixed hot water is installed upstream of the flow control valve, or an indirect flow detector is installed, so the flow detector is installed downstream of the flow control valve. Unlike the conventional method, there is no false detection due to stacking of scale components or the presence of air, further increasing safety. (4) Since the flow rate control valve is installed in the mixing flow path, even in the unlikely event of a failure, only the hot water side will be opened and the hot water will be turned off, unlike when the hot water side flow path and the water side flow path are installed independently. It is safe and there is no danger that it may be supplied.

[Brief explanation of the drawing]

[Fig. 1] Diagram of a hot water supply system using a hot and cold water mixing type water heater according to an embodiment of the present invention.

[Figure 2] Cross-sectional view of the same example

[Figure 3] Diagram of a hot water supply system using a conventional hot water mixing type water heater

[Figure 4] Cross-sectional view of the conventional example

[Explanation of symbols]

37 Hot water tap (flow control valve) 38 Entrance of hot water 39 Water entrance 40　Mixed water outlet 41 Valve frame 42 Hot water side flow path 43 Water side flow path 44, 45 Valve body (mixed valve body) 53 Motor (drive device) 55 Thermistor (temperature detector) 56 Controller 57 Temperature setting device 58 Mixing channel 59 Flow rate switch (flow detector)

Claims (1)

[Claims] A valve body having an inlet for hot water and an outlet for mixed hot water, a mixing valve body that adjusts the opening degree of a hot water side flow path and a water side flow path in this valve body, and a driving valve body for driving this mixing valve body. A driving device such as a motor, a temperature setting device for setting the temperature of mixed hot water, a flow rate control valve provided in the mixing flow path connected to the outlet of the mixed hot water, and a temperature detection provided on the upstream side of this flow rate control valve. a flow detector installed on the upstream side of the flow rate control valve that directly or indirectly detects the supply state of the mixed hot water, and comparing the signals of the temperature setting device and the temperature detector. A hot water mixing type hot water supply device comprising a controller that controls the drive device and starts and stops the drive device in response to supply and stop states of mixed hot water.