JPH0330755Y2 - - Google Patents

Description

[Detailed description of the invention] (Application field and overview of the invention) The present invention has a structure that prevents the generation of condensate when performing small-capacity heat exchange in a heat exchanger, especially a small-sized, large-capacity heat exchanger. The heat absorption pipe is equipped with a heat absorption section with a large number of fins and a bypass circuit located outside the combustion chamber to bypass this, and the flow rate on the heat absorption section side is limited according to the heat exchange. This is to maintain the temperature of the part at a temperature at which condensate does not occur and to prevent the boiling phenomenon in the endothermic part during initial heating.

(Prior art and its problems) Japanese Patent Application No. 61-95985 (Japanese Unexamined Patent Publication No. 61-95985) has already been proposed as a method for preventing drainage generated in the heat absorption part of a heat exchanger.
-252848) was proposed.

This proposal has the configuration shown in Figure 3,
A heat absorption tube 11 equipped with a large number of fins 10,
11 are connected in parallel to form a heat absorption section, and a bypass circuit 2 is arranged in parallel to the heated circuit 1 including this heat absorption section.
The temperature at the outlet of the heated circuit 1 side is detected by the detection means 30, and the flow ratio adjustment valve 3 is inserted at the junction of the bypass circuit 2 and the heated circuit 1, and the temperature of the heated circuit 1 side is detected by the detection means 30. In order to maintain the temperature above a certain level, the flow rate ratio adjusting valve 3 is operated according to the temperature detected by the detection means 30 to limit the flow rate on the heated circuit 1 side.

In this one, a sensor 51 detects the temperature of hot water.
A proportional control device 5 is provided which compares the output from the hot water temperature setting device 52 and operates a control valve 53 inserted into the gas circuit, and the outlet hot water temperature can be arbitrarily set by this proportional control device 5. can.

In this type of water heater, when the water temperature set by the proportional control device 5 is low, drainage is likely to occur in the heat absorption part of the heated circuit 1, especially under the condition of the lowest set temperature. In this case, since the outlet temperature on the endothermic part side is maintained at a constant temperature or higher by the flow rate ratio adjusting valve 3, the generation of drain can thereby be prevented.

However, in this prior example, boiling may occur within the heat absorption tube 11 at the start of heating.

At the start of heating, the temperature at the outlet of the heated circuit 1 is low, and the flow rate on the heated circuit 1 side is in a restricted state. However, at this time, since the tapped water temperature is also lower than the set temperature, the combustion amount of the burner 50 is set to be large by the proportional control device 5. That is, even though the combustion amount of the proportional control device 5 is large, the flow rate of the heated circuit 1 is restricted to an excessively small amount.

(Technical Issues) The present invention is equipped with a proportional control device 5 that controls the combustion amount of the burner 50 by comparing the hot water temperature from the water heater and the hot water set temperature, and connects the heat exchanger to the heated circuit. A bypass circuit 2 is provided in parallel with the heated circuit 1, and a flow rate ratio adjustment valve 3 is provided to adjust the flow rate ratio between the heated circuit 1 and the bypass circuit 2. By comparison, the flow ratio adjustment valve 3 is operated to control the flow rate of the heated circuit 1, thereby maintaining the surface temperature of the heat absorption part of the heated circuit 1 above a certain temperature. In order to prevent the boiling phenomenon in the heated circuit 1 at the initial stage of heating, the object is to prevent the flow rate of the heated circuit 1 from being reduced more than necessary at the early stage of heating.

(Technical Means) The technical means of the present invention taken to solve the above-mentioned technical problems are as follows: Inserting a normally closed valve 4 on the upstream side of the junction of the bypass circuit 2 with the heated circuit 1; , hot water temperature detection means 4 on the outlet side of the heated circuit 1
0 is inserted, and when the hot water temperature detecting means 40 reaches the initial set temperature or higher, the output device 41 opens the valve 4.
and the initial set temperature is set to a temperature lower than and close to the outlet temperature of the heated circuit 1 corresponding to the lowest outlet temperature set by the proportional control device 5. be.

(Operation) The above technical means of the present invention operates as follows.

In the early stage of ignition, the temperature of the outlet water is low, so the combustion amount of the burner 50 is set to be large by the operation of the proportional control device 5.

At this point, the temperature at the outlet of the heated circuit 1 is significantly lower than the set temperature for high temperature maintenance, so the flow rate ratio at the confluence of the heated circuit 1 and the bypass circuit 2 is The flow rate from the heated circuit 1 set by the regulating valve 3 is set to a minimum throttle state. On the other hand, at this point, the temperature at the outlet of the heated circuit 1 is lower than the initial setting temperature, that is, the outlet temperature of the heated circuit 1 corresponding to the lowest hot water temperature set by the proportional control device 5, and Since the temperature is lower than the approximate temperature, the valve 4 is in a closed state by the output of the output device 41. Since the sum of the flow rates in the heated circuit 1 and the bypass circuit 2 is approximately constant, in the above state, the flow rate on the heated circuit 1 side is greater than the flow rate in the minimum throttle state.

Therefore, at the initial stage of ignition when the combustion amount of the burner 50 is set to be large, that is, until the heat exchanger reaches a steady state, a sufficient flow rate on the heated circuit 1 side is ensured.

After that, when the water temperature on the heated circuit 1 side rises,
When the temperature detected by the hot water temperature detection means 40 exceeds the initial setting temperature, the output device 41 enters the output state and opens the valve 4. As a result, both the heated circuit 1 and the bypass circuit 2 are brought into communication.

Thereafter, the flow ratio adjustment valve 3 is operated according to the change in the outlet temperature of the heated circuit 1 to control the flow rate ratio of the heated circuit 1, so that the temperature of the heated circuit 1 reaches the high temperature maintenance setting temperature, that is, the heated circuit 1. The temperature is maintained at such a level that no condensation occurs in the heat absorbing portion of the heating circuit 1.

In addition, the temperature of hot water from the water heater is controlled by a proportional control device 5.
The hot water temperature is maintained at the set temperature by
The above operation will proceed under this condition. Therefore, it is possible to prevent drain from occurring throughout the control range of the proportional control device 5.

(Effects) Since the present invention has the above configuration, it has unique effects.

At the initial stage of heating the heated circuit 1 of the heat exchanger,
The flow rate in the heated circuit 1 is temporarily set to a large flow rate state regardless of the flow ratio adjustment valve 3, and this flow rate state is maintained until the outlet temperature reaches the set temperature. The disadvantage that the circuit 1 to be heated becomes overheated can be prevented.

(Example) An example of the above-described present invention will be described based on FIG. 2.

In this embodiment, the heat absorption part of the heat exchanger is connected to the burner 5.
The heat absorption part 1a on the exhaust side and the heat absorption part 1b on the burner 50 side are arranged in parallel in two stages on the downstream side of the exhaust flow of the burner 50, and are located on the downstream side of the exhaust flow of the burner 50. The heat absorbing portion 1a corresponds to the heated circuit 1 described above.

Further, in this embodiment, the detection means 30 and the hot water temperature detection means 40 are so-called temperature-sensitive pellets that expand in volume according to the ambient temperature, and the valve stem is made to protrude from the heat-sensing portion containing the temperature-sensitive pellets. This realizes a valve drive mechanism.

That is, the flow rate ratio adjusting valve 3 has a valve stem 32 protruding from a heat-sensitive part 31 provided at the outlet of the heated circuit 1, and an output valve 34 connected to the valve stem 32, so that the ambient temperature of the heat-sensitive part 31 can be adjusted. When the temperature reaches or exceeds the set temperature, the valve stem 32 is advanced and moved, thereby adjusting the flow rate ratio between the heated circuit 1 and the bypass circuit 2. For this reason, the output valve 34 is provided at the confluence of the heated circuit 1 and the bypass circuit 2, and the valve port 12 on the heated circuit 1 side and the valve port 21 on the bypass circuit 2 side, which are opened at this confluence point, are mutually connected. An output valve 34 is located between the valve ports 12 and 21 facing each other,
Tapered surfaces at both ends face each valve port. Therefore, the heat sensitive part 31 and the valve shaft 32 as well as the valve port 12,
21 is located coaxially.

Next, a combination of the hot water temperature detection means 40 and the output device 41 is used as a heat sensing section 42, and this heat sensing section 42
is inserted into the auxiliary circuit 43 which is branched from the upstream side of the flow ratio adjustment valve 3 and detoured to the above-mentioned confluence point in the heated circuit 1, and the tip of the valve shaft 44 which becomes the output shaft of the heat sensitive section 42 is bypassed. It faces a normally closed valve 4 provided upstream of the flow ratio adjustment valve 3 of the circuit 2. Further, a normally open valve body 45 attached to the valve shaft 44 is inserted in the middle of the auxiliary circuit 43, and after the valve 4 opens, the valve body 45 closes with a certain time delay. These interlocking relationships are set in .

Note that the temperature sensing output of the heat sensing section 31 is controlled by the proportional control device 5.
When the outlet temperature is set to the lowest temperature by The mouth 12 is in the minimum aperture state. In this embodiment, the minimum hot water temperature is set to 37°C, and at this time, the heat-sensitive portion 3
In order to set a temperature-sensing output of 1 and ensure the hot water temperature, the output valve 34 is provided with an orifice 33 that communicates the outlet of the heat absorption section 1a with the downstream side of the output valve 34.

Therefore, when the outlet temperature of the heat absorbing section 1a shifts to a higher temperature side than the above state, the output valve 34 is moved toward the valve body 21 by the output of the heat sensing section 31. For this reason, in this embodiment, the set temperature of the heat sensitive part 31 that starts the movement of the flow ratio adjustment valve 3 is 70°C.
It is set to .

Further, the set temperature at the start of thermal output of the other heat sensitive section 42 is set to a temperature lower than that of the heat sensitive section 31 (for example, 30° C.).

Therefore, in the initial stage of ignition of the burner 50, the heat sensing part 42 and the heat sensing part 31 are in a non-output state, and the heat absorption part 1 is in a state where the bypass circuit 2 is cut off.
Only part a is placed in communication, and overheating of the heat absorbing part 1a can be prevented by the above-mentioned conditions.

In this embodiment, since both ends of the output valve 34 are tapered, the hot water on the side of the heat absorption part 1a and the hot water on the side of the bypass circuit 2 are easily mixed.

Furthermore, in the above embodiment, since the valve shaft 44 that operates in synchronization with the valve 4 is arranged in parallel, the valve shaft 44 is closed when hot water at a normal temperature is being drawn, and the output is The flow rate ratio adjustment by the valve 34 becomes effective.

Further, in the above embodiment, a temperature-sensitive pellet is used to operate the valve 4 and the output valve 34, but this may be used in combination with an electric drive means and a sensor.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the principle of the present invention, Fig. 2 is an explanatory diagram of an embodiment of the present invention, and Fig. 3 is an explanatory diagram of a prior example. ...Finn, 11...
Heat absorption pipe, 1a... heat absorption part, 2... bypass circuit,
3...Flow rate ratio adjustment valve, 31...Heat sensitive section, 32...
... Valve shaft, 34 ... Output valve, 4 ... Valve, 40 ... Hot water temperature detection means, 41 ... Output device, 42 ... Heat-sensitive section.

Claims (1)

[Scope of utility model registration request] A proportional control device 5 that controls the combustion amount of the burner 50 by comparing the hot water temperature from the water heater and the hot water set temperature.
The heat exchanger is equipped with a bypass circuit 2 in parallel with the heated circuit 1, and a flow ratio adjustment valve 3 for adjusting the flow rate ratio between the heated circuit 1 and the bypass circuit 2 is provided, and the heated circuit 1 and the set temperature for high temperature maintenance, the flow rate ratio adjustment valve 3 is operated to control the flow rate of the heated circuit 1, thereby raising the surface temperature of the heat absorption part of the heated circuit 1 to a certain temperature or higher. A normally closed valve 4 is inserted at the upstream side of the junction of the bypass circuit 2 with the heated circuit 1, and a hot water temperature detection means 40 is inserted at the outlet side of the heated circuit 1. The hot water temperature detecting means 40 and the output device 41 are interlocked so that the output device 41 opens the valve 4 when the hot water temperature detecting means 40 becomes equal to or higher than the initial set temperature.
A heat exchanger in which the initial set temperature is set to a temperature lower than and close to the outlet temperature of the heated circuit 1 corresponding to the lowest outlet temperature set by the proportional control device 5.