JP2013204885A - Main stop system water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a water hammer phenomenon in a region in which primary supply water supply pressure supplied to a water supply path is high without using a pressure buffer in a main stop system water heater that includes a burner 4 and a heat exchanger 5 heated by the burner, and has a water stop valve 7 and a water governor 8 interposed in a water supply path 5a to the heat exchanger and that also has a hydraulic driven gas valve 11 which is opened through operation of the water governor when water is supplied to the water supply path with the water stop valve open and which is interposed in a gas supply path 4a to the burner.SOLUTION: A water stop valve 7 is constituted into a motor-driven type which is opened and closed by a motor 7a. A hydraulic sensor 17 is provided which detects primary water supply pressure. Then valve opening operation speeds of the water stop valve 7 are changed according to the primary water supply pressure.

Description

  The present invention relates to an original water heater having a burner and a heat exchanger heated by the burner, and having a water stop valve and a water governor interposed in a water supply path to the heat exchanger.

  In this type of water heater, the gas supply path to the burner is provided with a water pressure responsive gas valve that is opened by the operation of the water governor when water is passed through the water supply path by opening the stop valve. It is installed. Then, by opening the water stop valve, the water pressure responsive gas valve is opened, the burner is ignited, and hot water is supplied to the hot water outlet pipe downstream of the heat exchanger.

  The water governor has a function of adjusting the secondary supply water pressure supplied to the heat exchanger to a constant pressure lower than the primary supply water pressure supplied to the water supply channel. Further, conventionally, a water-stop type water heater that uses an electric water-stop valve that is opened and closed by a motor is also known (see, for example, Patent Document 1).

  By the way, depending on the region, the water supply pressure (primary water supply pressure) of the water supply may become very high. In such an area, when the water stop valve is opened, before the water governor's pressure regulating function is exerted, a high water supply pressure acts on the outlet pipe downstream of the heat exchanger, so-called water hammer phenomenon. This causes problems such as the tapping pipe vibrating.

  In order to solve such a problem, there is conventionally known a pressure buffer that includes a diaphragm between an inlet pipe and an outlet pipe of a heat exchanger (see, for example, Patent Document 2). However, in a small water heater, the size of the pressure buffer that can be installed is limited, and the water hammer phenomenon cannot be sufficiently suppressed.

JP 2009-24751 A Japanese Examined Patent Publication No. 58-17381

  In view of the above points, an object of the present invention is to provide a primary water heater capable of suppressing the water hammer phenomenon in an area where the primary feed water pressure is high without using a pressure buffer.

  In order to solve the above-described problems, the present invention includes a burner and a heat exchanger heated by the burner, and a water stop valve and a water governor are interposed in a water supply path to the heat exchanger. In a water-stop type water heater in which a water pressure responsive gas valve is opened by the operation of the water governor when water is passed through the water supply channel by opening the water stop valve The valve is configured to be an electric type that is opened and closed by a motor, and includes a switching unit that can switch a valve opening operation speed of the water stop valve according to a primary water supply pressure supplied to a water supply passage. .

  According to the present invention, in an area where the primary supply water pressure is high, the opening speed of the stop valve can be reduced by the switching means. According to this, the water stop valve is slowly opened, and the pressure regulating function of the water governor is exhibited while the water stop valve is being opened. Therefore, even in a region where the primary feed water pressure is high, the secondary feed water pressure does not increase rapidly when the stop valve is opened, and the water hammer phenomenon can be suppressed.

The front view of the former stop-type water heater of embodiment of this invention. Explanatory drawing which shows the structure of the water heater of embodiment. The flowchart which shows the content of the speed switching control of the water stop valve which the controller of the water heater of embodiment performs. (A) The graph which shows the change of the secondary feed water pressure when the valve opening operation speed of a water stop valve is fast, (b) The graph which shows the change of the secondary feed water pressure when the valve opening operation speed of a stop water valve is slow.

  Referring to FIG. 1, reference numeral 1 denotes a main body of a main-stop type water heater according to an embodiment of the present invention. An operation button 2 and a capability switching lever 3 are arranged on the front surface of the container body 1. In the vessel 1, as shown in FIG. 2, a burner 4, a heat exchanger 5 heated by the burner 4, and a controller 6 are arranged.

  The operation button 2 is locked at the push-in position by the first push operation, and returns to the non-push-down position by the second push operation. An operation switch 2 a that is turned on at the push position of the operation button 2 is connected to the controller 6. It is connected. The operation button 2 is rotatable to a predetermined hot water temperature adjustment range between “low” and “high” and a “water” position outside the hot water temperature adjustment range. A selection switch 2 b that is turned off in the “water” position is connected to the controller 6.

  The water supply path 5a to the heat exchanger 5 is supplied to the heat exchanger 5 and the electric water stop valve 7 that is opened and closed by a motor 7a via a mechanical interlocking mechanism such as a cam in order from the upstream side. A water governor 8 having a function of adjusting the secondary water supply pressure to a constant pressure lower than the primary water supply pressure supplied to the water supply path 5a, and a water amount adjusting valve 9 whose opening degree changes in conjunction with the rotation of the operation button 2. And are installed. A hot water discharge head 5c is connected to the downstream side of the heat exchanger 5 via a hot water discharge pipe 5b.

  The gas supply path 4a to the burner 4 is opened by the operation of the water governor 8 when water is passed through the water supply path 5a by opening the gas solenoid valve 10 and the stop valve 7 in order from the upstream side. A water pressure responsive gas valve 11, a gas governor 12 for adjusting the gas pressure to a constant value, and a gas amount adjusting valve 13 whose opening degree changes in conjunction with the swing of the capacity switching lever 3 are interposed. A water flow switch 14 that is turned on when the water pressure responsive gas valve 11 is opened is connected to the controller 6.

  The burner 4 is provided with an ignition electrode 15a that generates a spark by the operation of an igniter 15 that is controlled by a controller 6 and a flame rod 16 that is a flame detection element.

  When the operation switch 2a is turned on, the controller 6 performs hot water supply operation control if the selection switch 2b is turned on, and performs water supply operation control if the selection switch 2b is turned off. In the hot water supply operation control, first, the igniter 15 is operated simultaneously with the operation switch 2a being turned on, and the water stop valve 7 is opened to allow water to flow through the water supply passage 5a. At this time, the water pressure responsive gas valve 11 is opened by the operation of the water governor 8 and the water flow switch 14 is turned on. When the water flow switch 14 is turned on, the gas electromagnetic valve 10 is opened to ignite the burner 4. Thus, water is supplied to the heat exchanger 5 with the burner 4 burned, and a hot water supply operation for supplying hot water to the hot water discharge pipe 5b is performed. On the other hand, in the water supply operation control, when the operation switch 2a is turned on, the igniter 15 is not operated only by opening the water stop valve 7, and the gas electromagnetic valve 10 is not opened even when the water flow switch 14 is turned on. . Therefore, a water supply operation is performed in which the burner 4 is not burned and supplied to the heat exchanger 5 and cold water is supplied to the hot water outlet pipe 5b.

  By the way, the primary water supply pressure is generally about 0.2 MPa, but there are also regions where the primary water supply pressure becomes 0.4 MPa or more. In an area where the primary water supply pressure is high, when the stop valve 7 is opened, the secondary water supply pressure is greatly overshooted as shown in FIG. 4A before the pressure regulating function of the water governor 8 is exhibited. To do. As a result, the high feed water pressure acts on the hot water discharge pipe 5b on the downstream side of the heat exchanger 5 to cause a so-called water hammer phenomenon, causing problems such as vibration of the hot water discharge pipe 5b.

  Therefore, in the present embodiment, the water pressure sensor 17 is connected to the portion of the water supply passage 5a on the upstream side of the water stop valve 7. And the controller 6 is provided with the switching means 6a which switches the valve opening operation speed of the water stop valve 7 according to the primary feed water pressure detected by the water pressure sensor 17 as a functional means comprised by a program. Since the valve opening operation speed of the water stop valve 7 is determined by the rotation speed of the motor 7a for the water stop valve 7, the rotation speed of the motor 7a is switched according to the primary water supply pressure.

  The contents of control by the switching means 6a, that is, the contents of the speed switching control of the water stop valve 7 are as shown in FIG. First, when it is determined in STEP1 that the operation switch 2a is turned on, the process proceeds to STEP2, and it is determined to which level the primary water supply pressure detected by the water pressure sensor 17 is. If the primary feed water pressure is at a low level (for example, the primary feed water pressure <0.2 MPa), the process proceeds to STEP 3 where the rotation set speed NS of the motor 7a is set to a relatively fast first speed Nh. On the other hand, if the primary water supply pressure is at a medium level (for example, 0.2 MPa ≦ primary water supply pressure <0.4 MPa), the routine proceeds to STEP 4 where the rotation setting speed NS of the motor 7a is set to a medium second speed Nm. . If the primary feed water pressure P is at a high level (for example, 0.4 MPa <primary feed water pressure), the process proceeds to STEP 5 to set the rotation set speed NS of the motor 7a to a relatively slow third speed Nl. Next, proceeding to STEP 6, the motor 7 a is rotated at the rotation set speed NS to open the water stop valve 7. The time required for the water stop valve 7 to be fully opened from the closed state is defined as a valve opening time t. The first speed Nh, the second speed Nm, and the third speed Nl are each set to, for example, 1 second. The rotation speed is 1.5 seconds and 2 seconds.

  According to this, when the primary supply water pressure is high, the valve opening operation speed of the water stop valve 7 becomes slow, and the water stop valve 7 opens slowly. Therefore, the pressure regulating function of the water governor 8 is exhibited during the opening of the water stop valve 7, and the overshoot of the secondary water supply pressure is reduced as shown in FIG. 4 (b). Accordingly, even in a region where the primary feed water pressure is high, the water hammer phenomenon can be suppressed without causing a sudden rise in the secondary feed water pressure when the stop valve 7 is opened.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above embodiment, the valve opening operation speed of the water stop valve 7 is switched to three stages according to the primary feed water pressure, but the number of switching stages may be two stages or four or more stages. It is also possible to switch the valve opening operation speed steplessly according to the primary feed water pressure.

  In the above embodiment, the valve opening speed of the water stop valve 7 is automatically switched according to the primary feed water pressure detected by the water pressure sensor 17, but a dip switch for switching the valve opening speed is provided. The installer of the boiler may operate the dip switch based on the measurement result of the primary feed water pressure to manually switch the valve opening operation speed of the water stop valve 7. In this case, the switching means is constituted by a dip switch.

  DESCRIPTION OF SYMBOLS 4 ... Burner, 4a ... Gas supply path, 5 ... Heat exchanger, 5a ... Water supply path, 6 ... Controller, 6a ... Switching means, 7 ... Stop valve, 7a ... Motor, 8 ... Water governor, 11 ... Water pressure responsive gas Valve, 17 ... Water pressure sensor.

Claims (1)

A burner and a heat exchanger heated by the burner are provided. A water stop valve and a water governor are provided in the water supply path to the heat exchanger, and the water stop valve is opened in the gas supply path to the burner. In the water-stop type water heater provided with a water pressure responsive gas valve that is opened by the operation of the water governor when the water is passed through the water supply channel,
The water stop valve is configured to be an electric type that is opened and closed by a motor, and includes a switching means that can switch the valve opening operation speed according to the primary water supply pressure supplied to the water supply passage. A non-stop water heater.

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