JPH0820123B2 - Safety device for prevention of empty heating of water heater with bath kettle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water heater with a bath kettle, in which an exhaust gas prevention switch is provided on an exhaust guide plate which covers the bath heat exchanger.
The present invention relates to a safety control device for preventing air heating, which minimizes deformation of an exhaust guide plate due to thermal expansion of a bath heat exchanger and ensures operation of a water heating prevention switch.

2. Description of the Related Art In order to prevent the temperature rise of the synthetic resin part of the water heating prevention switch, the air heating prevention safety device of the water heater with a bath kettle of recent years is attached to the exhaust guide plate fitted around the bath heat exchanger, Only the heat sensitive part of the prevention switch is designed to contact the fin block of the bath heat exchanger.

An example of the above-described safety control device for preventing water heating in a water heater with a bathtub will be described below with reference to FIG. 5 of the drawings.

(18) has a circular tube (34) in the center and a number of fins 18 in the longitudinal direction.
A fin block with a. Reference numerals 19a and 19b are drum pipes having an elliptical cross section, which are in partial contact with the fin 18a in the longitudinal direction, and the fin block (18) and the drum pipe 19a,
Both ends of 19b are fixed so that they do not move. The safety device for preventing dry heating (31) is attached to the fin block (18) at the base in the longitudinal direction so that the heat-sensitive surface (28) of the dry heating prevention switch (27) contacts the fin 18a of the fin block (18).
And the fin block (18) forming the flange surface (24) having the same dimension as the width (23) of the short side of the elliptical drum pipe 19a and the outer circumference of the drum pipe 19a. An exhaust guide plate (33) and an empty-fire prevention switch (27) are fixed by two screw screws 30a and 30b.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, as described above, in the exhaust guide plate (33) forming the flange surface (24) having the same dimension as the dimension of the width portion (23) on the short side of the drum pipe 19a, the fin block ( 18)
Since both ends of the drum pipe 19a and the drum pipe 19a are fixed, the strain in the lateral direction due to thermal expansion cannot be absorbed, causing deformation, and the heat-sensitive surface (28) of the empty-water prevention switch (27) has fins 18
There was a problem that it became easy to get away from a, and the operation of the switch when it was empty was impaired.

In view of the above problems, the present invention forms a flange surface on the exhaust guide that is wider than the dimension of the width portion on the short side of the thin drum pipe, and is thin on the flange surface near the root-side water-fire prevention switch mounting portion. Spot welding the drum pipe and the fin block and the hook plate that fits in the gap,
Prevents the heating of the water heater with bath kettle, which prevents deformation of the flange surface and ensures the operation of the water heating prevention switch, by making it possible to absorb strain in the short direction due to thermal expansion of the thin drum pipe. A device is provided.

Means for Solving the Problems In order to solve the above problems, the safety device for preventing water heating of a water heater with a bath kettle of the present invention has one fin block, an air heating prevention switch, and both sides of the fin block. Fitted into a thin drum pipe and a fin block that are closely attached,
The flange surface that is wider than the width of the short side of the thin drum pipe contacts the entire length of the curved surface of the thin drum pipe, and the fin block is attached to the flange surface near the attachment part of the dry fire prevention switch on the side surface at the root side of the fin block. The exhaust guide plate is formed by spot welding a hook plate that is fitted into a gap with the thin drum pipe.

Effect In the present invention, the hook plate is sandwiched in the gap between the fin block and the thin drum pipe, and the flange surface of the exhaust guide plate is formed wider than the short side curved surface width of the thin drum pipe. It is possible to reliably operate the dry-water prevention switch regardless of the strain force due to the thermal expansion of the thin drum pipe.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

(1) is a water heater with a bath kettle, (2) is a gas block for feeding gas to the bath burner (3) and the hot water supply burner (4) through the bath gas pipe (5) and the hot water supply gas pipe (6) , (7) is a controller, 8a and 8b are hot water supply and ignition electrodes separately provided for bath, 9a and 9b are flame detectors provided for hot water supply and bath, and (10) is a hot water supply burner (4 ) Is an exhaust cover that joins the hot water supply heat exchanger (11) provided directly above and the bath heat exchanger (12) provided directly above the bath burner (3) as an exhaust gas passage together. The hot water supply heat exchanger (11) has an inlet and an outlet directly connected to the water supply joint (13) and the hot water supply joint (14). (15) is an air supply / exhaust fan connected to the exhaust cover (10), and (16) is an exhaust duct connecting the inlet to the air supply / exhaust fan (15) and sending out exhaust gas to the blowout louver (17).
The bath heat exchanger (12) consists of a single fin block (18) and thin drum pipes 19a, 19b closely attached to both sides of the fin block (18). Ends are upper and lower pipes 22 for circulation to the bathtub
It is configured by being connected to a drum (21) provided with a and 22b. The safety device for preventing empty heating fits into the fin block (18), and the flange surface (24) wider than the short side width portion (23) of the thin drum pipe 19a makes a surface contact with the entire length of the curved surface portion (25) of the thin drum pipe 19a. Alternatively, while making line contact, use the screws 30a, 30b to attach the dry-water prevention switch (27) so that the heat-sensitive surface (28) of the dry-water prevention switch (27) contacts the root side surface (26) of the fin block (18). A hook plate that fits into the gap between the fin block (18) and the thin drum pipe 19a on the flange surface (24) near the mounting portion (31) where two stepped holes (29) are provided for attachment. The exhaust guide plate (33) is formed by spot welding the (32). The exhaust guide plate (33) is connected to the exhaust cover (10).

In the above-described embodiment, the signal from the controller (7) causes discharge from the ignition electrodes 8a, 8b to the burner (3) for bath and the burner (4) for hot water supply, and the gas pipe for bath (5) passes through the gas block (2). ), The gas is sent to the bath burner (3) and the hot water supply burner (4) through the hot water supply gas pipe (6) and burned, whereby the flame detectors 9a and 9b operate and the combustion is continued. On the other hand, the air required for combustion is sent into the bath burner (3) and the hot water supply burner (4) by the air supply / exhaust fins (15), and the high-temperature exhaust gas enters the water supply joint (13) for cold water and hot water. While exchanging heat in the heat exchanger (11) and flowing out from the hot water inlet joint (14), the other bath heat exchanger (1
Also in 2), the cold water that has entered from the circulation lower pipe 22b is heat-exchanged through the fin block (18) and the thin drum pipes 19a and 19b to become hot water, and is sent out from the circulation upper pipe 22a as a natural circulation action. After the heat exchange, the exhaust gas passes through the exhaust cover (10), is sucked into the air supply / exhaust fan (15), passes through the exhaust duct (16), goes out from the louver (17) and goes out of the water heater with a bath kettle (1). Sent out. The fin block (18) and thin drum pipes 19a, 19b when the bath is empty
The temperature rises rapidly, and the thin drum pipes 19a, 19b whose both ends are connected to the drums (20) and (21) thermally expand outward. However, the flange surface (24) of the exhaust guide plate (33) is on the short side width portion (23) of the thin drum pipe 19a.
It is wider than it does not deform and it is a fin block (18)
Exhaust is performed by the hook plate (32) provided on the flange surface (24) near the mounting portion (31) where the heating prevention switch (27) is attached so that the heat-sensitive surface (28) contacts the root side surface (26). Since the positioning of the guide plate (33), the fin block (18), and the thin drum pipe 19a is established, the dry fire prevention switch reliably operates.

EFFECTS OF THE INVENTION As described above, according to the dry-burning prevention safety device of the present invention, the following effects can be obtained.

Since the flange surface of the exhaust guide plate is made wider than the width of the short side curved surface of the thin drum pipe, the fin block and the thin drum pipe are not directly subjected to the thermal expansion strain force when the thin drum pipe is heated. The deformation of the attached exhaust guide plate can be prevented, and the operation of the dry fire prevention switch can be reliably performed.

On the flange surface of the exhaust guide plate near the attachment part of the dry-fire prevention switch, there is a hook plate that fits in the minute gap between the fin block and the thin drum pipe. Also, since the exhaust guide plate at the attachment portion of the dry water prevention switch is prevented from being deformed and the positional relationship among the fin block, the thin drum pipe, and the exhaust guide plate can be established, the operation of the dry water prevention switch can be ensured.

Since the operation of the boil-prevention switch is reliable, it is possible to reliably prevent premature boiling off when using a normal bath.

[Brief description of drawings]

FIG. 1 is a layout view showing an internal structure of a water heater with a bath kettle in one embodiment of the present invention, FIG. 2 is a front view of a bath heat exchanger unit with an empty-burn prevention safety device in FIG. 2 is a plan view of FIG. 2, FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 5 is a cross-sectional view of a conventional bath heat exchanger with an air-burning prevention safety device. 18: Fin block, 19a, 19b: Thin drum pipe, 24: Flange surface, 25: Curved portion of thin drum pipe, 27: Dry fire prevention switch, 32: Hook plate, 33: Exhaust guide plate

Claims (1)

[Claims] 1. A fin block, an empty-fire prevention switch, a thin drum pipe that is provided in close contact with both sides of the fin block, and a width portion on the short side of the thin drum pipe fitted into the fin block. A gap between the fin block and the thin drum pipe on the flange surface in the vicinity of the attachment part of the dry-fire prevention switch on the side surface at the base side of the fin block while contacting the entire curved surface portion of the thin drum pipe with a wider flange surface. Safety device for preventing water heating of a water heater with a bath kettle, which is equipped with an exhaust guide plate obtained by spot welding a hook plate that fits into the.