JPH0145011Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a safety device for water heaters.

(Prior Art) Conventionally, as shown in Fig. 4, a water heater is equipped with a water supply pipe B on the upstream side of a heat exchanger A, a hot water supply pipe C on the downstream side, and a heat source D such as a gas burner. , A type with a pressure relief valve F to prevent the pressure in the pipe from increasing due to residual fire from the heat source D and damaging the connecting part E etc. is known, for example, from Utility Model Application No. 114349/1983. ing.

In this case, if a pressure relief valve F is installed in the water supply pipe B, which is upstream of the heat exchanger A, when the internal pressure becomes high and the pressure relief valve F is activated, high-temperature steam will flow back to the flow switch G, water governor H, etc. A pressure relief valve F is installed in the water supply pipe C to prevent damage to the functional parts of the
It was installed outside the vessel box J in consideration of steam disposal.

(Problem that the invention attempts to solve) As mentioned above, when the internal pressure increases due to the residual fire of the heat source D, the pressure relief valve G prevents damage to the connecting part E, etc.
In order to prevent damage to functional parts due to backflow, steam can also be discharged outside the container box J, but in cold weather, the pressure relief valve F outside the container box J becomes connected, making it impossible to achieve the above purpose. There was a problem.

(Means for solving the problem) The present invention includes a water supply pipe on the upstream side of the heat exchanger, a hot water supply pipe on the downstream side, and a heat source such as a gas burner, and a heat source such as a gas burner. In a water heater that is equipped with a pressure relief valve with an air charge plug, and is further provided with a drain plug inside the container box at the lower end of the water supply pipe, the drain plug is provided with the drainage channel facing outside the container box. is provided with a pressure relief valve, and the operating pressure of the pressure relief valve is higher than the operating pressure of the pressure relief valve with air cage plug.

(Example) Reference numeral 1 denotes a heat exchanger, to which a water supply pipe 2 is connected to the upstream side, and a hot water supply pipe 3 is connected to the downstream side thereof.

4 is a heat source such as a gas burner that heats the water that has passed through the heat exchanger 1.

Reference numeral 6 denotes a pressure relief valve with an air charge plug provided outside the container box 5 in the hot water pipe 3 downstream of the heat exchanger 1. As shown in FIG.
2, and an air charge plug 66 that opens and closes the opening 65 with a knob 64. When the pressure inside the pipe increases, the pressure relief valve 63 opens the opening 62 against the force of the spring 61. . Also, when the knob 64 is loosened, the air charge plug 66 opens the opening 65.

Reference numeral 7 denotes a pressure relief valve with a drain plug, which is provided in the vessel box 5 at the lower end of the water supply pipe 2 upstream of the heat exchanger 1. As shown in FIG. 3, this pressure relief valve 7 with drain plug includes a pressure relief valve 73 that closes an opening 72 with a spring 71, and a drain plug 76 that opens and closes the opening 75 with a knob 74. A tip 78 of the knob 74, which has a drainage channel 77 inside, protrudes from the container box 5.

When the pressure inside the pipe increases, the pressure relief valve 73 opens the opening 72 against the force of the spring 71, and the knob 74 opens.
When loosened, the drain valve 76 opens the opening 75. The operating pressure of this pressure relief valve 73 is higher than the operating pressure of said pressure relief valve 63, for example the setting 14 of the pressure relief valve 63.
Kg/cm ² and pressure relief valve 73 setting is 30Kg/cm ² ,
It's summery.

A flow switch 8 opens a gas valve 9 to supply gas when the heat source 4 is a gas burner when it senses the flow of water. 10 is a water governor, and 11 is a pipe connection portion. Further, reference numeral 12 denotes a freeze prevention heater, which prevents freezing inside the container body 5 in cold weather by means of a control member (not shown).

13 is an external pipe, 14 is a hot water outlet, 15 is a hot water tap, and 16 is a water tap.

(Function) When the water supply tap 16 and hot water supply tap 15 are opened now, the flow switch 8 is activated to supply gas to the gas burner as the heat source 4. At this time, the gas burner serving as the heat source 4 is ignited by an ignition device (not shown), and hot water is supplied from the outlet 14. Hot water tap 1
When 5 is closed, the flow of water is stopped and the gas supply to the heat source 4 is stopped by the flow switch 8, so that the heat source 4 is extinguished.

If the hot water tap 15 is closed and there is no water flow, but for some reason a residual fire hits the heat source 4, the pressure inside the pipe increases, but the operating pressure of the pressure relief valve 6 is lower than that of the pressure relief valve 73. The pressure relief valve 63 moves against the spring 61 to open the opening 62 and the steam is discharged from the opening 62, so that the pipe connecting portion 11 and the like are not damaged. Further, since the opening 62 is located outside the vessel 5, the inside of the vessel 5 is not affected by high temperature steam. Furthermore, functional parts such as the flow switch 8 and the water governor 10 are not damaged by high-temperature steam.

Next, during cold weather, freezing inside the container box 5 can be prevented to some extent by, for example, operating the heater 12, but if freezing occurs in the external piping 13, high pressure is applied to the non-frozen parts inside the container. In addition, the pressure relief valve 6 with air charge plug is also often frozen because it is located outside the vessel. At this time, the other pressure relief valve 73 acts to open the opening 72 without freezing, thereby preventing damage to the pipe connection 11, etc.

The water drain plug 76 is useful for draining water when the water heater is not in use or when it is so cold that the heater 12 etc. cannot prevent freezing inside the container.
6 is opened for draining water.

(Function) According to the present invention, when the pressure inside the pipe increases due to residual fire, etc., the pressure relief valve 63 on the downstream side of the heat exchanger acts to release the pressure. When the external piping 13 freezes in cold weather, the pressure relief valve 63 may also freeze, but the other pressure relief valve 73 is located inside the vessel and does not freeze. This works effectively and eliminates the problems of the conventional method.
Furthermore, since it is only necessary to provide a pressure relief valve to the drain valve provided for draining water when not in use or during cold weather that cannot be prevented by a heater, etc., the structure is extremely simple and has a good effect.

[Brief explanation of drawings]

Figure 1 is an overall configuration diagram of the present invention, Figures 2 and 3
The figure is an explanatory diagram of the main part thereof, and FIG. 4 is a diagram showing a conventional example. 1...Heat exchanger, 2...Water supply pipe, 3...Hot water pipe, 4...Heat source, 5...Equipment box, 6...Pressure relief valve with air charge plug, 6...Pressure relief valve, 66
... Air charge plug, 7 ... Pressure relief valve with water drain plug, 73 ... Pressure relief valve, 76 ... Water drain plug, 77
...Drainage channel.

Claims (1)

[Scope of utility model registration request] The heat exchanger includes a water supply pipe on the upstream side, a hot water supply pipe on the downstream side, and a heat source such as a gas burner, and a pressure relief valve with an air charge plug is provided outside the body box of the hot water supply pipe, and furthermore, the lower end of the water supply pipe In water heaters in which a drain plug is provided inside the container box and its drainage channel is exposed to the outside of the container box, a pressure relief valve is installed in the drain plug and the operating pressure of the pressure relief valve is controlled. A safety device for a water heater, characterized in that the operating pressure is higher than the operating pressure of the pressure relief valve with air cage plug.