JPS5818076Y2 - Purification device for heat exchange tube in heat exchanger - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for purifying the inner wall of a multi-row tube for heat exchange used in a heat exchange section of a heat exchanger.

In various heating furnaces, the heat of exhaust gas is recovered for the purpose of increasing thermal efficiency, and a heat exchanger is often used as a recovery means. For example, heat is transferred to combustion air.

By the way, generally speaking, exhaust gas contains a large amount of dust, so in order to maintain good heat transfer inside the heat exchanger, it is necessary to prevent dust from adhering to the inner wall of the exhaust gas heat radiation passage. Is required.

For this reason, rotary heat exchangers having a dust removal function are often used in heat exchangers such as heating furnaces, and are commonly called rotary heaters.

However, in conventional rotary heaters, it is difficult to completely seal the rotating movable parts, and furthermore, there is a problem in that the thermal efficiency inevitably decreases due to leakage in the parts.

On the other hand, in a shell-and-tube heat exchanger that has no moving parts in its structure, when the above-mentioned exhaust gas is passed through the heat exchange tubes, there is no known means for removing dust in the prior art. As the operating time of the heat exchanger accumulates, the heat transfer effect decreases, and therefore, the shell-and-tube heat exchanger has not yet been put into practical use as a system using the above-mentioned exhaust gas.

The present invention was developed in view of the current situation, and the purpose of the present invention is to clean the exhaust gas dust adhering to the inner wall surface at any time without interrupting the heat transfer operation. An object of the present invention is to provide a purification device for the above-mentioned multi-row tubes for heat exchange.

Hereinafter, the present invention will be explained based on an illustrated embodiment.

1 to 3 show a heat exchanger equipped with multiple rows of heat exchange tubes with an exemplary purifying device, in which hoods 2, 3 are placed on both sides of a box-shaped shell 1. The combustion air blown to the heating combustor enters through the hood 2 and flows through the shell 1.

Therefore, multiple rows of heat exchange tubes 4 are installed vertically inside the shell 1, penetrating from the top surface to the bottom surface, and these tubes 4 are interposed in the middle of the exhaust gas flue, and the exhaust gas flows from above to below shell 1, during which
Combustion air is heated by heat radiation from the exhaust gas.

By the way, on the tube sheet 5 forming the upper plate of the shell 1, a flat purifying fluid supply chamber 6 is formed in the shape of a compartment, and the upper end of the tube 4 is opened at the lower part of the chamber 6. Hereinafter, the formation of the purification fluid supply chamber 6 to which the purification fluid is supplied will be explained with reference to FIGS. 4 to 6.

An inner tube 7 made of a short tube with a small diameter is inserted into the upper end opening of the tube 4, and the inner circumferential wall of the tube 4 and
A slight gap 8 is left between the inner tube 7 and the outer periphery thereof.

Thus, the upper end of the inner tube 7 passes through the outer wall 9 of the purification fluid supply chamber 6, and then expands into a dish shape and opens.

The interior space of the purified fluid supply chamber 6 is divided into a plurality of rows of small chambers 6a by a large number of partition plates 10 in a direction perpendicular to the flow direction of combustion air (hereinafter referred to as the width direction of the shell 1). However, the partition plates 10 are provided in every second row of the inner tubes 7.

Incidentally, between the inner tubes 7 in each small chamber 6a, purification fluid introduction pipes 11.12 and 13.14 in two stages, upper and lower, are arranged on both sides of the purification fluid supply chamber 6 with the center line in the width direction of the shell 1 as the border. Each of the introduction pipes 11 to 14 passes through the side plate 15 of the purified fluid supply chamber 6, and flanges 11a and 12a are formed at the opening thereof.
The inner ends of the shells 1 to 14 are closed near the center line in the width direction of the shell 1, and there are a number of blow-off holes 11b,
12b are opened at appropriate intervals.

Note that a suitable position between the container tubes 11 to 14 is supported by a bracket 16 hanging from the outer wall 9.

In addition, the flange openings of the container tubes 11 to 14 are connected to a purification fluid supply tube (not shown).

Here, the operation of the purifying apparatus of the embodiment configured as described above will be described in the case where steam is used as the purifying fluid.

First, during normal operation of the heat exchanger, the purified fluid introduction pipe 1
With the supply openings 1 to 14 closed, combustion air and exhaust gas are supplied from the hood 2 and the inner tube 7, respectively.

In this state, since the purified fluid supply chamber 6 is a closed chamber, the exhaust gas that has flowed into the inner tube 7 passes through the heat exchange tube 4 as it is, and the operation is similar to that in a general multi-tube heat exchanger. The combustion air is heated by the heat of the exhaust gas.

However, as the operation time accumulates, exhaust gas dust adheres to the inner wall of the tube 4. In this case, steam at a predetermined pressure is supplied to the purified fluid introduction pipes 11 to 14 while the operation continues. Clean the inner wall of the tube 4.

That is, the supplied pressurized steam flows through the outlet 11a,
Since the steam is dispersed from 12a and bottled into each small chamber 6a, the steam pressure in contact with the gap 8 at the upper end of each tube 4 is maintained uniformly, and as a result, the flow rate of the steam injected into the tube 4 from the gap 8 is , it becomes equal.

Due to the suction effect generated by this steam jet, the flow rate of the exhaust gas flowing from the inner tube 7 into the tube 4 can be accelerated to more than double without any obstruction to the flow. The dust adhering to the inner wall of the pipe is effectively removed by the synergistic effect of the melting and dissolving action of the steam and the blowing action of the gas flow, and is discharged into the flue.

If the steam supply capacity is large, it is possible to clean all the heat exchange tubes 4 at the same time, and if the supply capacity is not so large, it is possible to clean each small chamber 6a.
It is also possible to supply steam at different times each time, and to separate the tubes 4 and clean them one after another.

Note that during such a purification operation, the upper end opening of the inner tube 7 is expanded into a dish shape, so that the pressure loss of the exhaust gas caused by the inner tube 7 is kept to a minimum.

Here, in the test of the example structure conducted by the present inventor, the heat exchange tube diameter was 50 mm, and the inner tube diameter was 45 m.
m, and the internal pressure of the steam chamber 6 was set to 0.1 kg/Cm.
2, the steam did not flow back into the inner tube 7, and the dust on the inner wall of the tube 4 was thoroughly removed.

Note that the purification fluid referred to in the present invention refers to pressurized gas such as steam, air, nitrogen, etc., or pressurized gas in general in which solvent vapor, fine particles, etc. are suspended in order to increase the purification function.

As described above, according to the multi-row heat exchange tube purification device according to the present invention, the piping is formed so that the purification fluid can be injected into the upstream side of the heat exchange tube through which exhaust gas flows,
Since purifying fluid is injected at any time to remove dust on the inner wall of the tube, the heat transfer inside the heat exchanger is always maintained in a good condition, which makes it possible to operate the heat exchanger using this type of exhaust gas. It has the effect of increasing efficiency.

[Brief explanation of the drawing]

Fig. 1 is a front view of a heat exchange tube purification device showing one embodiment of the present invention, Fig. 2 is a side view of the same, Fig. 3 is a plan view of the same, and Fig. 4 is the same as that of Fig. 3. The enlarged views of part IV, FIGS. 5 and 6, correspond to lines ■-■ and VI-VI in FIG. 4, respectively.
FIG. 4...Heat exchange tube, 6...Purified fluid supply chamber, 7...Inner tube, 8...
...Gap, 9...Outer wall.

Claims (1)

[Scope of utility model registration request] In an inner wall purification device for multiple rows of heat exchange tubes that are piped through a heat exchanger, a chamber to which purification fluid is supplied when necessary is formed as a partition on the heat exchange gas inflow side of the heat exchanger. , the upstream end of each heat exchange tube is opened into the same chamber, and the downstream end of the inner tube, which is a short tube, is in the opening with a slight gap between it and the inner wall of the heat exchange tube. and the upstream side of the inner tube penetrates the outer wall of the chamber and serves as an inlet for heat exchange gas. Tube purification device.