JPH0134052Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive control device for a pump in a water heater.

BACKGROUND ART Conventionally, there is a hot water supply system for home use in which hot water is supplied from a hot water supply source such as a boiler to a hot water storage tank, and the hot water stored in the hot water storage tank is then forcefully delivered to a plurality of faucets such as hot water mixing faucets using a pump. In such water heaters, there are various usage conditions such as opening all the faucets or selectively opening some of the faucets, and the hot water to each faucet is adjusted according to the usage conditions. In order to appropriately manage the supply amount, a control means for controlling the drive of the pump is provided.

Conventionally, this control means uses a pressure switch that detects the pressure in the hot water supply path from the pump to each faucet and starts and stops the pump. The pressure switch is inserted into the pump's power circuit, and closes to start the pump when the pressure in the hot water supply path falls below the lower limit of the set pressure, and opens when the pressure in the hot water supply path rises above the upper limit of the set pressure. This stops the pump.

By the way, when some of the plurality of faucets are closed, the pressure in the hot water supply path may exceed the upper limit of the pressure switch, and in this case, the pressure switch opens and stops the pump. However, since hot water continues to be supplied from the faucet even after the pump has stopped, the pressure in the hot water supply path drops rapidly and becomes lower than the lower limit of the pressure switch, so the pump is restarted. In other words, the pump repeatedly starts and stops, which impairs the durability of the pump and makes the supply of hot water to the faucet unstable.

The present invention was developed with the aim of solving these technical problems, and when the amount of hot water required is small compared to the pump's discharge capacity, it reduces the number of times the pump starts and stops repeatedly and improves the durability of the pump. The present invention provides a pump drive control device that can stably supply a necessary amount of hot water to a faucet.

That is, in addition to the pressure switch, the present invention is equipped with a flow rate switch that detects the flow rate of hot water flowing through the hot water supply path, closes when the flow rate is higher than the set flow rate, and opens when the flow rate is lower than the set flow rate, and these flow rate switches and pressure switches are connected in parallel to the power supply circuit of the pump. It was inserted into.

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the water heater of this embodiment supplies hot water from a hot water supply source A such as a boiler to a hot water storage tank B, temporarily stores hot water there, and connects a plurality of hot water mixing faucets, for example two, from the hot water storage tank B. Hot water is supplied to C ₁ and C ₂ . The hot water storage tank B has a heat insulating structure, and a hot water supply pipe 3 facing upwardly inside thereof is connected to a hot water supply source A. A lead-out pipe 4 is connected to the lower part of the hot water storage tank B.
Hot water in the hot water tank B is supplied from this lead-out pipe 4 to the hot water mixing taps C ₁ and C ₂ via a pump P and pipes 6, 7a, and 7b installed in the machine room 5 at the bottom of the hot water tank B. .

The hot water mixing faucets C ₁ and C ₂ are connected to the water supply source, ie, the water supply, via pipes 8a and 8b, respectively, and supply hot water directly or via the shower heads 9a and 9b.

In such a water heater, there is a hot water supply path from the pump P to the hot water mixing taps C ₁ and C ₂ , such as a pressure switch 1 that detects the pressure in the pipe 6 and operates it, and a pressure switch 1 that operates by detecting the pressure inside the pipe 6 . A sensing and actuating flow rate switch 2 is provided. The pressure switch 1 is connected via a conduit 12 to a connecting pipe 11 that connects the pipe 6 and the accumulator 10, and closes when the pressure inside the pipe 6 drops below the lower limit of the set pressure, for example, 0.8 kg/cm ² . It opens when the pressure inside the pipe 6 rises above the upper limit of the set pressure, for example 1.1 kg/cm ² . The flow rate switch 2 is provided between the discharge pipe 13 connected to the discharge port of the pump P and the piping 6, and is configured to switch when the flow rate of hot water discharged from the pump P and passing through the piping 6 exceeds a set flow rate of, for example, 2/min. Similarly, it closes when the flow rate falls below the set flow rate of 2/min.

These pressure switch 1 and flow rate switch 2 are connected to a pump P and an AC power source E as shown in FIG.
It is inserted in parallel to the power supply circuit F that connects the Therefore, when one of the pressure switch 1 and the flow rate switch 2 is closed, the power supply circuit F is closed and the pump P is started, and when both switches 1 and 2 are opened, the power supply circuit F is opened and the pump P is started. is stopped.

In the water heater of this embodiment as described above, when the two mixing taps C ₁ and C ₂ are open and one of them, for example, C ₂ is closed, the pressure inside the pipe 6 increases and the flow rate decreases. . As shown in FIG. 4, the pressure in the pipe 6 rises rapidly with respect to the change in flow rate, and instantaneously exceeds the upper limit set value of the pressure switch 1, causing the pressure switch 1 to open. On the other hand, the flow rate switch 2 is closed until the flow rate in the pipe 12 drops to the set flow rate, and the pump P continues to be driven. When the flow rate in the pipe 12 falls below the set flow rate, the flow rate switch 2
opens to open the power supply circuit F and stop the pump P. A flow rate lower than the set value of the flow rate switch 2 is not actually used, and is generated temporarily when the faucet, that is, the hot water mixing faucet C ₁ and C ₂ is closed. In other words, when the hot and cold water mixing taps C ₁ and C ₂ are opened and the pressure in the pipe 12 drops below the lower limit setting value of the pressure switch 1, and once the pump P is started, the hot and cold water mixing taps C _{1 and} C 2 are opened.
Pump P continues to operate until C ₂ is closed, and the required amount of hot water is stably supplied to hot water mixing taps C ₁ and C ₂ .

As described above, the present invention detects the pressure in the hot water supply path from the pump to the faucet, closes it when the set pressure is below the lower limit, and opens when it exceeds the upper limit, and detects the flow rate of hot water flowing through the hot water supply path. Equipped with a flow rate switch that closes when the flow rate is higher than the set flow rate and opens when the flow rate is lower than the set flow rate.
These pressure switches and flow rate switches are inserted in parallel into the pump's power supply circuit. In other words, when the required amount of hot water is less than the discharge capacity of the pump, even if the pressure switch opens due to a sudden rise in pressure in the hot water supply path, the flow rate switch remains closed until the flow rate in the hot water supply path falls below the set flow rate. The pump continues to drive until this flow rate switch is opened, extending the pump driving time compared to conventional systems, reducing the number of times the pump is started and stopped, and improving the durability of the pump. It is possible to appropriately manage the flow rate over a wide range and stably supply the required amount of hot water to the faucet.

In addition, according to the configuration that uses the pressure switch and flow rate switch in combination, even if the discharge capacity of the pump changes due to differences in the frequency of the AC power supply, the flow rate can be managed as in the case of controlling only with a conventional pressure switch. The range does not change, the flow rate can be appropriately managed within the range of the set value of the flow rate switch, and the pump can be made substantially versatile.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of a water heater equipped with the device of the present invention, Figure 2 is a sectional view taken along the - line in Figure 1, Figure 3 is a circuit diagram, and Figure 4 shows the relationship between pressure and flow rate in the hot water supply path. This is a graph showing. In the figure, B...Hot water tank, _C1 , _C2 ...Hot water mixing faucet, P...Pump, 1...Pressure switch, 2...
Flow rate switch, F...Power circuit.

Claims (1)

[Scope of utility model registration request] In a water heater that includes a hot water storage tank and a pump that pressure-feeds hot water from the water storage tank to multiple faucets, the pressure in the hot water supply route from the pump to the faucets is detected and the pressure is closed when the set pressure is below the lower limit value, and the upper limit value is closed. A pressure switch that opens when the hot water flow rate exceeds a value, and a flow rate switch that detects the flow rate of hot water flowing through the hot water supply path, closes when the flow rate is higher than a set flow rate that is set lower than the flow rate corresponding to the upper limit value of the pressure switch, and opens when the flow rate is lower than the set flow rate. , a pump drive control device in which a pressure switch and a flow rate switch are inserted in parallel into the pump's power supply circuit.