JPH04184016A - Gas hot-water supply device - Google Patents

Abstract

PURPOSE:To enable a plurality of gas-fired water heaters to be divided into two groups which can be operated sequentially, by providing, between a solenoid-driven ON-OFF valve and a driving power supply, a pressure difference detection switch which connects the valve and the power supply to each other when water pressure becomes lower on the hot water supply side than on the feed water supply side and the pressure difference exceeds a set pressure. CONSTITUTION:When hot water is supplied by a gas-fired water heater 10, feed water supplied to the water heater 10 receives resistance while passing through the interior of the water heater 10, for example, through a heat exchanger 16. Therefore, water pressure becomes lower on the side of a hot water supply pipe 50 than on the side of a feed water supply pipe 40. The pressure difference increases as the opening of a faucet J is enlarged to increase the flow rate of water through the water heater 10. When the pressure difference reaches a predetermined level, a pressure difference detection switch 71 is turned ON, whereby a driving current is passed from a driving power supply 80 to a solenoid-driven ON-OFF valve 61, whereby the valve 61 is opened, and feed water is supplied also to a gas-fired water heater 20. As a result, hot water is supplied by operating the two water heaters 10, 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gas water heater that includes a plurality of gas water heaters connected in parallel.

[Prior Art] As a conventional gas water heater of this type, there is one shown in FIG. 4, for example. This gas water heater is composed of two gas water heaters 1 and 2, and each gas water heater 1 and 2 is
It is equipped with electromagnetic proportional control valves 1c, 2c for adjusting the amount of gas supplied to heat exchangers 1a, 2a, nozzles 1b, 2b, and burners 1b, 2b. In addition, each gas water heater 1,
2 are respectively connected to the water supply pipe 3 via branch pipes 3a and 3b, and are connected to the hot water supply pipe 4 via branch pipes 4a and 4b.
It is connected to the. Note that reference numeral 5 denotes a control unit having a microcomputer, and the control unit 5 calculates the necessary amount of heat based on the water supply amount, the water supply temperature, and the target hot water supply temperature, and operates the electromagnetic proportional control valve so that this amount of heat can be obtained. 1c,
This is to adjust the opening degree of 2c.

In the gas water heater with the above configuration, when the water supply amount reaches the minimum operating flow rate of the gas water heaters 1 and 2, the gas water heaters 1 and 2
operate at the same time. In other words, the amount of water supplied is 1
, 2, the respective gas water heaters 1 and 2 will not operate unless the amount reaches the sum of the minimum operating flow rates of the gas water heaters 1 and 2. For this reason, there is an inconvenience that only a small amount of hot water can be supplied.

Therefore, as shown in FIG. 4, a flow rate sensor 6 is installed in the water supply pipe 3, and an electromagnetic shut-off valve 7 is installed in the branch pipe 3b, whereby the gas water heater l is installed.

It has been proposed that 2 be operated sequentially. That is, at the beginning of water supply to the gas water heater, the electromagnetic on-off valve 7 is closed, and when the amount of water supplied reaches the minimum operating flow rate of the gas water heater 1, the control unit 5 first operates the gas water heater 1. When the amount of water supplied increases further and exceeds the sum of the minimum operating flow rates of the gas water heaters 1.2, the control unit 5 operates the gas water heater 2 in addition to the gas water heater 1 (Japanese Patent Laid-Open No. 63 -273757 Publication, JP-A-64-14524
(see publication).

[Problems to be Solved by the Invention] In a gas water heater that is configured to sequentially operate the gas water heaters 1 and 2 by installing a flow rate sensor 6 and an electromagnetic on-off valve 7, it is possible to operate the gas water heaters 1 and 2 at the same time. Compared to the one that is operated, the control unit 5 has a gas water heater 1,
A function is added to sequentially operate 2. For this reason, the circuit board constituting the microcomputer of the control unit 5 cannot be shared with a system that operates all gas water heaters at the same time, and there is a problem in that an expensive circuit board must be prepared separately. there were.

This invention was made to solve the above problem, and it goes without saying that a plurality of gas water heaters can be divided into some gas water heaters and other gas water heaters and operated sequentially. An object of the present invention is to provide a gas water heater in which a circuit board constituting a microcomputer can be used in common with a gas water heater configured to operate all gas water heaters at the same time.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a plurality of gas water heaters connected in parallel, and an electromagnetic shut-off valve is installed on the water supply side of at least one gas water heater. In the gas water heater, the pressure between the electromagnetic on-off valve and the drive power source that causes the valve to open by passing a drive current through it is lower than the pressure on the hot water supply side or the water supply side, and the differential pressure is greater than the set pressure. Accordingly, the present invention is characterized in that a differential pressure detection switch is provided to connect between the electromagnetic on-off valve and the drive power source.

For reasons described later, when the number of gas water heaters is n, an electromagnetic on-off valve is installed on the water supply side of (n-1) gas water heaters, and a differential pressure detection switch is installed on each electromagnetic on-off valve. (n-1) are installed corresponding to the valve, and 1
For the th differential pressure detection switch, the pressure on the upstream side of any electromagnetic on-off valve is introduced as the pressure on the water supply side, and m (m
=2.3°..., for the (n-1)th differential pressure detection switch, it is desirable to introduce the pressure on the downstream side of the (m-1)th electromagnetic on-off valve as the pressure on the water supply side.

In addition, the electromagnetic on-off valve and differential pressure detection switch (n-1)
When installing multiple pressure switches, the pressure on the upstream side of the electromagnetic on-off valve is introduced as the pressure on the water supply side of all (n-1) differential pressure detection switches, and each differential pressure detection switch opens the electromagnetic on-off valve. In some cases, the differential pressures to be caused are set to different magnitudes.

[Action] If the differential pressure between the water supply side pressure and the hot water supply side pressure is below a predetermined set pressure, the solenoid on-off valve closes, and some gas water heaters that do not have an electromagnetic on-off valve close. It only works.

When the differential pressure exceeds the set pressure, the differential pressure detection switch or electromagnetic on-off valve and the drive power source are connected. As a result, the electromagnetic on-off valve opens, and some other gas water heaters equipped with electromagnetic on-off valves also operate.

Here, when the number of gas water heaters is n, (n-1
) An electromagnetic on-off valve is installed for each of the gas water heaters, and (n-1) differential pressure detection switches are installed corresponding to each electromagnetic on-off valve, and the first differential pressure detection switch is used for water supply. The pressure on the upstream side of any electromagnetic on-off valve is introduced as the pressure on the side, m (m = 2.3..., n-1)
If the pressure on the downstream side of the (m-1)th electromagnetic on-off valve is introduced as the pressure on the water supply side to the differential pressure detection switch, n gas water heaters can be sequentially operated. In this point, the pressure on the upstream side of the electromagnetic on-off valve is introduced as the pressure on the water supply side of all (n-1) differential pressure detection switches, and each differential pressure detection switch has a differential pressure that causes the electromagnetic on-off valve to open. The same holds true when they are set to different sizes.

=Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a schematic configuration of the entire gas water heater according to the present invention, and this gas water heater includes three gas water heaters 10, 20, and 30.

In this embodiment, the gas water heaters 10, 20, and 30 have the same specifications, but gas water heaters with different specifications may be used. Further, the number of gas water heaters used may be two or four or more.

Each gas water heater 10, 20.30 has its water inlet 11.2
Sequentially from 1.31 to outlet 12, 22.32,
Feed water temperature sensors 13, 23, for detecting the feed water temperature
33, flow rate sensor 14, 24 for detecting water supply amount;
34, water governor 15°25.33, heat exchanger 16, 26
, 36, and a hot water outlet temperature sensor 17°27.37 for detecting the hot water temperature. Also,
Burners 18, 28.38 are also provided for heating the feed water via heat exchangers 16, 26.36 to 0.degree.

Each burner 18, 28.38 has an electromagnetic proportional control valve 19.2.
9.39 to a gas supply tA (not shown).

In addition, as described later, each burner 18, 28° 38 is
It is designed to be ignited when the amount of water supplied to the gas water heater exceeds the minimum operating flow rate.

Water supply port 11°21. of the gas water heater 10, 20.30.
31 are connected to the water supply pipe 40 via branch pipes 41, 42, and 43, respectively. On the other hand, gas water heaters 10, 20
．． 30 outlets 12, 22° 32 are connected to branch pipes 5, respectively.
1, 52, and 53 to the hot water supply pipe 50.

In addition, the code J is the faucet.

Normally closed electromagnetic on-off valves 61 and 62 are installed in the branch pipes 42 and 43, respectively. Each electromagnetic on-off valve 61.62 is
It is connected to the drive power source 80 via differential pressure detection switches 71 and 72, and opens when the differential pressure detection switches 71 and 72 are turned on.

The differential pressure detection switch 71 is configured as shown in FIG. That is, the differential pressure detection switch 71 consists of a differential pressure detection section 71A and a switch section 71B, and the differential pressure detection section 71A includes a detection section main body 7 in the shape of a hollow airtight container.
It is equipped with 11.

A diaphragm 712 is provided inside the detection section main body 711, and the inside of the detection section main body 711 is divided into a first pilot chamber 713 and a second pilot chamber 714 by this diaphragm 712. The first pilot chamber 713 is connected to the water supply pipe 40 so that supply water is introduced therein. On the other hand, the second pilot chamber 714 is connected to the branch pipe 51, and hot water discharged from the gas water heater 10 is introduced into the second pilot chamber 714. Further, a base end portion of a rod 715 is fixed to the center portion of the surface of the diaphragm 712 facing the second pilot chamber 714. This rod 715 is connected to the second pilot chamber 714 by a spring 716.
Diaphragm 712 from the side to the first pilot chamber 713 side
is energized via. The tip of the rod 715 penetrates the wall of the detection section main body 711 and projects to the outside.

The switch section 71B consists of a normally open switch 717 and a mounting bracket 718 for attaching the switch 717 to the detection section main body 711.
7 is attached with its switch piece 717a abutting against the tip of the rod 715. Switch piece 717
When contact a contacts contact 717b, switch 717 is closed (turned on).

In the differential pressure detection switch 71 configured as described above, the pressure in the second pilot chamber 714 becomes lower than the pressure in the first pilot chamber 713, and the differential pressure is the set pressure P.

In other words, the pressure on the hot water supply side becomes lower than the pressure on the water supply side, and the differential pressure becomes the set pressure P.

When the switch piece 717a becomes larger, the opening 71
5 and contacts the contact point 717b.

As a result, the switch 717 is turned on.

When the switch 717 is turned on, the drive power source 80 and the electromagnetic on-off valve 61 are connected, and the electromagnetic on-off valve 61 is opened. Note that the set pressure P1 can be changed by changing the urging force of the spring 716.

Here, when the differential pressure between the water supply side and the hot water supply side, for example, the differential pressure between the water supply pipe 40 and the hot water supply pipe 50, reaches the differential pressure P1 that turns on the switch 17, the gas water heater 10 .2
Let the minimum operating flow rate of 0 be Q, , Q, (Q, -02 in this example), and the flow rate in the water supply pipe 10 (-the water supply pipe 5
When Q is the flow rate within 0, Q>Ql+Qt is satisfied.

On the other hand, when the switch 717 is in the ON state, the switch 717 remains in the ON state even if the differential pressure becomes small (in case it becomes the set pressure P), the switch 717 remains in the ON state and
, (P, < P,), it becomes OFF state. In other words, this differential pressure detection switch 71 has hysteresis as shown in FIG.

Note that even when switching from the ON state to the FF state, Q > Q + + Q t holds true.

The differential pressure detection switch 72 is connected to the first pilot chamber or the downstream side of the electromagnetic on-off valve 61, and the pressure at which it switches from the ON state to the OFF state is set to a pressure P4, which is slightly higher than the pressure P. It differs from the differential pressure detection switch 7I in this respect, and has the same structure as the differential pressure detection switch 71 in other respects.

Note that the differential pressure detection switch 72 is formally different from the differential pressure detection switch 71 in that the second pilot chamber is connected to the branch pipe 52, but the pressures in the branch pipes 51 and 52 are almost the same. So there is no real difference.

Further, when the minimum operating flow rate of the gas water heater 30 is Q3, the differential pressure detection switch 72 is turned from the OFF state to the ON state,
And when switching from the ON state to the OFF state, Q>Q++Qt half Q3 holds true.

The gas water heater 10 includes a control section 100 for controlling the amount of gas supplied to the burner 18.

Note that the other gas water heaters 20 and 30 are also equipped with control units, but these control units are configured similarly to the control unit 100, so here, the control unit 1゛00 of the gas water heater 1° will be explained. The description and illustration of other control units will be omitted.

The control unit 100 is equipped with a microcomputer like a control unit installed in a normal gas water heater, and the control unit 1
The following signals are respectively input to 00. A supply temperature signal Tc1 indicating the temperature of water supplied to the gas water heater 10 is inputted from the water supply temperature sensor 13, and a flow rate signal wl indicating the amount of water supplied is inputted to the flow rate sensor 14. A hot water outlet temperature signal Th indicating the temperature of hot water discharged from the gas hot water supply lid 10 is input from the temperature sensor 17 . Furthermore, a target hot water supply temperature Th is input to the control unit 100 from a temperature setting unit (not shown) for setting the hot water supply temperature.

The control unit 100 controls the gas water heater 10 based on the various human power signals described above. That is, the amount of water supplied is calculated based on the flow rate signal Wl, and when the amount of water supplied to the gas water heater 10 reaches a predetermined minimum operating flow rate, the burner 18 is ignited.

Conversely, if the water supply amount is less than the minimum operating amount, burner 1
Extinguish 8.

The control unit 100 also controls the flow rate signal W1, the feed water temperature signal T
c, and the target temperature signal Tho, the gas water heater 1
Calculate the amount of heat required to reach 0, and calculate the amount of gas required to obtain that amount of heat. Then, the opening degree of the electromagnetic proportional control valve 19 is determined from the required gas amount, and the drive current A1 is output to the electromagnetic proportional control valve 19 so that the opening degree is obtained. Note that the hot water temperature signal Th.

is used as a feedback signal, and the drive current A is corrected as appropriate.

Of course, the control units of the other gas water heaters 20.30 also control the burner temperature based on the water supply temperature signals Tc, , Tc, the flow rate signals W, , W,, the water supply temperature signals Tc, , Tc, and the target water supply temperature Th. It controls the ignition and extinguishing of the valves 28 and 38, and outputs driving currents A, , A, to the respective electromagnetic proportional control valves 29 and 39.

Next, the operation of the gas water heater having the above configuration will be explained.

When the faucet J is opened, water is first supplied to the gas water heater 10 because the electromagnetic on-off valves 61 and 62 are closed.

When the amount of water supplied to the gas water heater 10 reaches the minimum operating flow rate, the burner 18 is ignited. As a result, hot water is first supplied by only one gas water heater 10.

When hot water is supplied by the gas water heater 10, the gas water heater 1
Since the water supplied to the gas water heater 10 encounters resistance when passing through the interior of the gas water heater 10, for example, the heat exchanger 16, the water supply pipe 50
The pressure on the water supply pipe 40 side is lower than that on the water supply pipe 40 side. This differential pressure is
The opening degree of the faucet J is increased and the flow rate flowing through the gas water heater 10 increases. Then, when the differential pressure reaches a predetermined set pressure Pl, the differential pressure detection switch 71 turns OFF.
N, and a driving current is passed from the drive type #80 to the electromagnetic on-off valve 61. As a result, the electromagnetic on-off valve 61 opens, and water is also supplied to the gas water heater 20. As a result, gas water heater t
Hot water is supplied by two units, o and 20.

In addition, assuming that the amount of water supplied is the same when hot water is supplied by only one gas water heater 10 and when it is supplied by two gas water heaters 10.20, the differential pressure in the latter is lower than the differential pressure in the former. Therefore, even if the set pressures of the differential pressure detection switches 71 and 72 are the same at Pl, the differential pressure detection switch 71 is
After entering the N state, the differential pressure detection switch 72 is turned to the O state.
It will never be N. Therefore, the gas water heater 30 and the gas water heater 20 will not operate at the same time. In this case, by setting the differential pressure at which the differential pressure detection switch 72 is turned on to be slightly higher than the pressure P, it is possible to reliably prevent the gas water heater 30 from operating at the same time as the gas water heater 20. .

Note that since the differential pressure detection switch 71 has hysteresis, it will not switch from the ON state to the OFF state due to a drop in the differential pressure immediately after the electromagnetic on-off valve 61 is opened.

Moreover, when the differential pressure detection switch 71 is switched to the ON state, Q>QI+Q! Therefore, the burner 17 of the gas water heater 10 will not be extinguished by opening the electromagnetic on-off valve 61.

When the faucet J is further opened, the differential pressure that has become lower than the set pressure P1 increases again. When the differential pressure reaches P, the differential pressure detection switch 72 is turned on and the electromagnetic on-off valve 62 is opened. As a result, the gas water heater 30 is activated, and hot water is supplied by the three gas water heaters 10, 20 and 30. Although the differential pressure decreases in this case as well, the differential pressure detection switches 71 and 72 do not turn off, and since Q>Q++Qt+Qs, the gas water heaters 10 and 20 continue to operate.

When the faucet J is closed to reduce the amount of water supplied while the three gas water heaters 10, 20, and 30 are supplying hot water, the differential pressure gradually decreases. Then, when the differential pressure becomes smaller than the pressure P, the differential pressure detection switch 72 is switched from the ON state to the OFF state. Then, the electromagnetic on-off valve 62 closes and the gas water heater 30 stops operating.

When the faucet J is further throttled and the differential pressure becomes smaller than the pressure P, the differential pressure detection switch 71 switches from the ON state to the OFF state, and the electromagnetic on-off valve 62 closes. As a result, the gas water heater 20 stops operating.

When the faucet J is closed, the gas water heater IO also stops operating.

In the above gas water heater, the gas water heater 10.20
．． The number of units used for 30 is switched using the differential pressure detection switch 71.
72, and the control unit 100 only controls the operating state of the gas water heater 10. therefore,
The microcomputer used in the control unit 100 can be the same as the microcomputer used in a conventional gas water heater that operates all gas water heaters at the same time without switching the number of units used. Therefore, the boards constituting the microcomputer can be shared.

This point also applies to the microcomputers used in the control units of the other gas water heaters 20 and 30.

Note that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the gist thereof.

For example, in the above embodiment, the differential pressure detection switch 7
1.72 on the hot water supply side, that is, as the pressure introduced into the second pilot chamber 714, the branch pipe 51.5
The branch pipes 51 and 52.5 are introduced from 2 respectively.
Since the pressures of pipe 5 and water supply pipe 50 are almost the same,
It may be introduced from any of the tubes 0, 51, and 52.53.

In the above embodiment, three gas water heaters 1.
0, 20.30 are operated one by one, but the electromagnetic on-off valve 61 and differential pressure detection switch 71 are omitted, and the two gas water heaters 10.20 are operated simultaneously.
Only the other gas water heaters 30 may be operated based on the differential pressure.

In addition, when using four gas water heaters and three electromagnetic on-off valves, if a differential pressure detection switch with the same configuration is installed on each electromagnetic on-off valve, install it on the fourth gas water heater. The first pilot chamber of the differential pressure detection switch is connected to the downstream side of the second electromagnetic on-off valve 62 installed in the third gas water heater 30. Generally, using n gas water heaters, (n-1) electromagnetic on-off valves and (n-1)
When installing differential pressure detection switches, the first pilot chamber of the first differential pressure detection switch is connected to the upstream side of any electromagnetic on-off valve, and
..., the first pilot chamber of the (n-1)th differential pressure detection switch is connected to the downstream side of the (m-1)th electromagnetic on-off valve.

Further, in the above embodiment, the differential pressure detection switch 72
The pressure on the downstream side of the electromagnetic on-off valve 61 is introduced as the pressure on the water supply side, but the pressure on the upstream side of the electromagnetic on-off valve 61, for example, the pressure in the water supply pipe 40 as shown by the imaginary line in FIG. You may also introduce it. However, in this case, the differential pressure detection switch, Chia 1, changes from ON to OFF.
The differential pressure when switching from FF to FF is P, the differential pressure when switching from OFF to ON is P, and the differential pressure of the differential pressure detection switch 72 is P3. When P4, P3>P,,
p, > p.

It is necessary to do so. Generally, the number of gas water heaters is n, and the number of electromagnetic on-off valves and differential pressure detection switches is (n-1
), each differential pressure detection switch changes from ON to OFF.
The differential pressure when switching to F is P, I+ P 3+ ”
'+ P tn-3, and each differential pressure detection switch or OF
The differential pressure when switching from F to ON is p,, P,, ll・ll, Ptn-.

Then, P , < P , <...< P tn-sp t<
p, <...<p,. −t (P z,, −2< P
+).

In addition, when (n-1) differential pressure detection switches are provided, and when the pressure on the downstream side of the electromagnetic on-off valve is introduced as the pressure on the water supply side of each differential pressure detection switch, like the differential pressure detection switch 72, Also, P 2 < P , < □−
<P! It is desirable to set it to n-2.

Furthermore, the differential pressure detection switch may have a different configuration from the differential pressure detection switch 71.72 used in this embodiment, and the electromagnetic on-off valve 61.62 may have the following configuration:
An electromagnetic proportional control valve may be used that can not only open and close, but also adjust the flow rate as necessary.

[Effects of the Invention] As explained above, in the gas water heater of the present invention, the pressure on the hot water supply side is changed from the pressure on the water supply side to This system is equipped with a differential pressure detection switch that connects the electromagnetic on-off valve and the drive power source when the differential pressure becomes higher than the set pressure. Not only can it be operated separately and sequentially with other gas water heaters, but the circuit board that makes up the microcomputer can also be shared with a gas water heater that operates all gas water heaters at the same time. Effects such as this can be obtained.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention; Figure 1 is a schematic configuration diagram thereof, Figure 2 is a sectional view showing a differential pressure detection switch, and Figure 3 is a cross-sectional view of a differential pressure detection switch. 0N-OF
FIG. 4, which is a diagram showing F characteristics, is a schematic configuration diagram showing an example of a conventional gas water heater. 10.20.30...Gas water heater, 40...Water supply pipe, 50...Hot water supply pipe, 61.62...Solenoid shut-off valve, 71
．． 72...Differential pressure detection switch.

Claims (3)

[Claims] (1) In a gas water heater that includes a plurality of gas water heaters connected in parallel and has an electromagnetic shut-off valve installed on the water supply side of at least one gas water heater, a driving current is passed through the solenoid shut-off valve and the solenoid shut-off valve. A differential pressure detection switch connects the electromagnetic opening/closing valve and the driving power source when the pressure on the hot water supply side becomes lower than the pressure on the water supply side and the differential pressure becomes larger than a set pressure between the driving power source and the driving power source that opens the valve. A gas water heater characterized by being provided with. (2) In the gas water heater according to claim 1, when the number of the gas water heaters is n, the electromagnetic on-off valve is (
n-1) each installed on the water supply side of the gas water heater,
The differential pressure detection switch corresponds to each electromagnetic on-off valve (n-
1) are installed, and the first differential pressure detection switch introduces the pressure on the upstream side of any electromagnetic on-off valve as the pressure on the water supply side, m (m = 2, 3, ..., n-1) A gas water heater characterized in that the pressure on the downstream side of the (m-1)th electromagnetic on-off valve is introduced into the th differential pressure detection switch as the pressure on the water supply side. (3) In the gas water heater according to claim 1, when the number of the gas water heaters is n, the electromagnetic on-off valve is (
n-1) each installed on the water supply side of the gas water heater,
The differential pressure switch corresponds to each electromagnetic on-off valve (n-1).
In addition, the pressure on the upstream side of the electromagnetic on-off valve is introduced as the pressure on the water supply side of all (n-1) differential pressure detection switches, and each differential pressure detection switch has a differential pressure that opens the electromagnetic on-off valve. A gas water heater characterized by having different pressures.