JPS5838313Y2 - Heat exchanger - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat exchanger, and particularly relates to an improvement of a gas-liquid or gas-air heat exchanger that utilizes exhaust gas from a boiler.

Normally, this type of heat exchanger uses exhaust gas from a boiler etc. as the heating gas, and the thermal energy contained in the exhaust gas is recovered as hot water, and the hot water obtained there is used in the manufacturing process or as boiler water supply. used for.

Furthermore, heat exchangers of this type are used for heating gases, for example for preheating air fed to boilers.

However, in this heat exchanger, dust such as fine dust and soot in the exhaust gas used, together with solidified moisture in the gas, may adhere to the heat transfer surfaces of heat exchange members such as fins and tubes, or become clogged between the fins. This not only significantly lowers the heat transfer performance but also increases the flow resistance of the exhaust gas in the heat exchanger, resulting in a large pressure loss, which has the disadvantage of adversely affecting combustion.

If such a situation occurs, it is necessary to detect the situation early and to clean or wash the heat transfer surface of the heat exchanger to remove the attached dust.

In order to deal with the above-mentioned problems, the present invention aims to provide a heat exchanger that can immediately detect and issue an alarm when the pressure loss in the heating gas heat exchanger becomes large. do.

In order to achieve the above object, the heat exchanger according to the present invention is characterized by a differential pressure detection device for detecting the pressure difference between the inlet side and the outlet side of the heating gas, and is activated by the output signal of the device. and an alarm device that automatically issues an alarm when the pressure difference exceeds a predetermined value.

More preferably, the abnormality can be detected by detecting the temperatures of the heating gas and the heated fluid.

Next, embodiments of the heat exchanger according to the present invention will be described with reference to the drawings.

As is clear from FIG. 1, the illustrated embodiment is a plate-fin type heat exchanger 1, the casing 2 of which is fitted with ducts 3.about.3' on both sides.

Each duct is connected to the exhaust gas passage by a flange 4.

Furthermore, an inlet pipe header 5 and an outlet pipe header 6 for a fluid to be heated, such as water, are installed in the casing 2, and each pipe header is connected to a pipe for supplying or discharging the fluid by a union joint 7, and a nozzle connector. 8 to the header of the heat exchanger body.

During operation, the exhaust gas passes through duct 1-3.3' to heat exchanger 1.
At the same time, the fluid to be heated enters the heat exchanger from the inlet pipe header 5, circulates through the tube, absorbs the heat of the exhaust gas, and is heated and taken out from the outlet pipe header 6.

As shown in the figure, the heat exchanger according to the present invention includes a differential pressure detection device 10 for detecting the pressure difference between the inlet side and the outlet side of exhaust gas, and this device 10 is connected to an alarm 12 by a lead wire 11. It is connected to the.

The differential pressure sensing device is preferably a differential pressure gauge connected to the inlet duct 3 and the outlet duct 3' as shown in FIG. It is converted into a signal, which is amplified and sent to the alarm device 12.

In addition, as a differential pressure detection device, pressure sensors 13 and 14 are installed in the inlet side duct 3 and the outlet side duct 3', respectively, as shown in Fig. 2, and these pressure sensors are connected to the differential pressure transducer 15. It may be something you have done.

Furthermore, as a preferred form of this heat exchanger, as shown in FIG. There is.

Preferably, these thermometers are of bimetallic type.

Since this heat exchanger has the above configuration, during operation, the pressure loss of the exhaust gas in the heat exchanger is detected by the differential pressure gauge 10 as a pressure difference between the exhaust gas on the inlet side and the outlet side of the heat exchanger.

Note that the standard pressure difference of the exhaust gas in the heat exchanger is adjusted during the trial run, and is 20 mm water column in one example.

As the operating period progresses, if dust adheres to or clogs the heat transfer surface, the flow resistance of exhaust gas increases and the pressure difference increases.

When the pressure difference exceeds a predetermined value, for example, twice the standard value, the alarm 12 is activated to issue an alarm, and it is possible to sense that the clogging due to dust has become severe.

If dirt due to dust is detected, the amount of exhaust gas blown can be increased slightly and cleaning can be carried out immediately when the system is not in operation.

Furthermore, if a thermometer 16 is provided, it is possible to detect the outlet temperature of the fluid to be heated, and if it is abnormally high, it may be possible that the pump is not operating or the flow rate is extremely small. Once you know that something is wrong, you can immediately return to normal operation.

Further, the inflow temperature of the exhaust gas can be detected by the thermometer 17.

Boiler exhaust gas is normally 180 to 250°C, but if the heat transfer surface has been treated with anti-corrosion treatment, abnormalities may occur if the temperature exceeds 300°C. It is advantageous to install

Note that if these thermometers are also connected to the alarm device 12, abnormal temperatures can be automatically detected.

Note that the alarm may be one that emits sound or light, or both, or any other type of alarm.

This type of heat exchanger often uses boiler exhaust gas, and since the boiler exhaust gas itself has a low pressure, adding excessive resistance will have a negative effect on combustion. It is advantageous in that there are few
Further, compared to unit type heat exchange elements, it is more advantageous in that maintenance and handling are easier.

As described above, according to the present invention, if dust adheres to and clogs the heat exchange member and the pressure loss of the exhaust gas increases, this can be immediately detected, and the problem can be immediately detected before any adverse effects occur. Measures such as cleaning can be taken.

[Brief explanation of drawings]

FIG. 1 is a perspective view of one embodiment of a heat exchanger according to the present invention, and FIG. 2 is a schematic side view of a heat exchanger showing another embodiment. In the figure, 1: heat exchanger, 3.3': duct, 10: differential pressure detection device, 12: alarm, 13.14: pressure sensor,
15: Differential pressure transducer.

Claims (4)

[Scope of utility model registration request] (1) Differential pressure detection for detecting the pressure difference between the inlet side and the outlet side of the heating gas of the heat exchanger in a gas-liquid or air-air heat exchanger that uses boiler exhaust gas, etc. and an alarm connected to the pressure difference detection device and activated by an output signal thereof when the pressure difference detected there exceeds a predetermined value. vessel. (2) The heat exchanger according to claim 1, wherein the differential pressure detection device is a differential pressure gauge connected to the artificial side duct and the outlet side duct of the heat exchanger. . (3) In the heat exchanger according to claim 1 of the above utility model registration claim, the differential pressure detection device includes a pressure sensor installed in the inlet side duct of the heat exchanger and an outlet side duct. A heat exchanger consisting of a pressure sensor and a differential pressure transducer connected to the pair of pressure sensors. (4) The heat exchanger according to claim 1 of the above utility model registration, wherein exhaust gas from a boiler is used as the heating gas, and the heat exchanger includes an appropriate number of plate fins depending on the output of the boiler. A heat exchanger consisting of type heat exchange elements.