JP2001141266A - Indirect steam humidifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indirect steam humidifier provided with a heat exchanger easy to remove scale adhering on the surface of it. SOLUTION: An indirect steam humidifier A, provided with a heating tank 1 in which water for vaporizing is stored and a heat exchanger 4 with the heating source of steam, can heat the water in the heating tank to vaporize and discharge the generated steam, wherein the heat exchanger 4 is formed with a cylindrical heat exchanger tube 40, the thick surrounding wall of the heat exchanger tube 40 is formed hollow as a steam flow path R and each of parts near both the ends of the heat exchanger tube 40 is arranged with the connecting holes 41 and 42 communicating with the steam flow path R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indirect steam humidifier for use in air conditioning of buildings, constant temperature and humidity chambers, and the like.

[0002]

2. Description of the Related Art Conventionally, primary steam generated by a boiler or the like is used as a heating source and supplied to a heat exchanger disposed in a heating tank, and the water is heated and evaporated by heat exchange with water in the tank. There has been an indirect steam humidifier that uses the generated secondary steam for humidification. It is widely used in hospitals, factories, district heating and cooling facilities, etc., since it has a low vaporization latent heat load, high generated steam cleanliness, and does not directly use electricity as a heating energy source.

The heat exchanger of the indirect steam humidifier withstands the pressure and temperature of the primary steam, secures a large heat transfer area, and maintains the flow rate of the primary steam so as to obtain high heat transfer efficiency. In addition, due to restrictions on work and limitations on the volume of the mounting space, a metal thin tube formed into a coil shape or a U shape, or a plurality of U shapes formed by connecting a plurality of tubes is used. ing. FIG. 5 shows an example of a conventional heat exchanger of an indirect steam humidifier.

In the indirect steam humidifier X shown in FIG. 5, a heat exchanger 200 in which a thin metal tube is formed in a coil shape is disposed inside a heating tank 100 for storing water for evaporation. The primary steam is introduced into the small tube, exchanges heat with the water in the heating tank 100 to generate secondary steam, and is discharged from the steam outlet 110 above the heating tank 100. FIG.
Inside, 210 is the primary steam inlet, 300 is the level gauge, 310 is the overflow pipe, 320 is the pressure equalizing pipe, 330 is the communication pipe, 400
Is a drain pipe, 500 is a drain valve, 600 is a water supply pipe, and 700 is a water supply valve.

At the outlet side of the heat exchanger 200, there is provided a condensed water discharge device 800 having an orifice-shaped opening. When sent to the lower part, it is raised by the upward action of the steam flow, and is discharged from the condensed water discharge device 800.

[0006]

However, in the indirect steam humidifier X, when the water in the heating tank 100 evaporates during operation, the water level in the heating tank 100 naturally drops, and the level gauge 300 Upon detection, the water supply valve 700 is opened, and makeup water is supplied into the heating tank 100. But,
Since impurities such as calcium and magnesium contained in the water do not evaporate, they accumulate in the heating tank 100, and as the operation of the indirect steam humidifier X is continued, the impurity concentration increases and a part becomes scale 900. Heating tank
It deposits on the inner peripheral surface of the heat exchanger 100 and the outer surface of the heat exchanger 200 and adheres.

The adhered scale 900 has an extremely low thermal conductivity as compared with the metal constituting the heat exchanger 200, causing a significant decrease in the heat transfer performance of the heat exchanger 200.

Therefore, in order to prevent the scale 900 from adhering, generally, a method is adopted in which the drain valve 500 is opened under certain conditions to discharge the water having a high impurity concentration, and replace it with fresh water. ing.

[0009] However, during the long-term humidification operation, the scale 900 is still gradually accumulated, so that the deterioration of the heat transfer performance cannot be ignored.

[0010] Therefore, it is necessary to stop the operation every time a certain period of time elapses, take out the heat exchanger 200, and remove the scale 900 adhered to the surface.

However, since the heat exchanger 200 is formed in a coil shape or another complicated shape, it is necessary for a person skilled in the art to take time carefully to remove the scale 900 from the entire surface. You have to work over it, which is not practical.

As a result, although expensive, the heat exchanger 200
Had to be replaced at regular intervals.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an indirect steam humidifier capable of easily removing scale adhered to the surface of a heat exchanger in order to solve the above problems.

[0014]

In order to solve the above-mentioned problems, according to the present invention, there is provided a heating tank for storing therein water for evaporation, and a heating tank disposed in the heating tank for removing steam. In an indirect steam humidifier comprising a heat exchanger serving as a heating source and heating and evaporating water in the heating tank and capable of discharging generated steam, the heat exchanger is provided by a tubular heat transfer tube. Forming a thick peripheral wall of the heat transfer tube in a hollow shape to form a steam flow passage, and further, near both ends of the heat transfer tube, a connection port communicating with the steam flow passage is provided, and one is provided with a steam inlet. And the other as a condensed water outlet.

According to the second aspect of the present invention, the partition member is helically mounted in the thick peripheral wall of the heat transfer tube formed in a hollow shape, and the steam flow path is helically formed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of an indirect steam humidifier A according to the present invention, FIG. 2 is an explanatory view of a heat exchanger, and FIG. 3 is an explanatory view showing another embodiment of the heat exchanger. is there.

In FIG. 1, reference numeral 1 denotes a cylindrical heating tank for storing clean water W therein, which has a steam discharge port 20 formed in a ceiling wall 1a and a steam discharge port 20 provided at the base end of a spray pipe. Can be connected and connected.

Further, a level gauge 3 is connected to a peripheral wall of the heating tank 1 through a communication pipe 11 and a pressure equalizing pipe 12 whose base ends are connected.
Is in communication with The same configuration as the water level detection sensor 30 shown in FIG. 31
Is an overflow tube.

A drain pipe 5 provided with a drain valve 6 and a water supply pipe 7 provided with a water supply valve 8 are communicatively connected to the bottom wall 1b of the heating tank 1. In addition, the ceiling wall 1a and the bottom wall 1b are detachably attached to the tank main body via a gasket 1c with screws 1d, and are configured to be easily disassembled and assembled while preventing steam from leaking.

Reference numeral 4 denotes a heat exchanger using steam as a heat source. The heat exchanger 4 is provided in the heating tank 1 and heats and evaporates water by exchanging heat with water in the heating tank 1. This is an essential part of the present invention.

Here, the configuration of the heat exchanger 4 according to the present embodiment will be described in detail.

The heat exchanger 4 is a cylindrical heat transfer tube made of metal.
The heat transfer tube 40 is formed by forming a thick peripheral wall of the heat transfer tube 40 in a hollow shape to form a steam flow path R. Further, near both ends of the heat transfer tube 40, a connection communicating with the steam flow path R is provided. A port is provided, one of which is a steam inlet 41 and the other is a condensed water outlet 42.

The heat transfer tube 40 is, as shown in FIG.
40a, the same length and the same length as the outer cylinder 40a.
a, and the gap at both ends is welded by a closing plate 40c or closed by other appropriate means, and a steam flow path R is provided between the outer cylinder 40a and the inner cylinder 40b.
And a steam inlet 41 and a condensed water outlet 42 communicating with the steam flow path R near both ends.

A primary steam supply pipe 43 is connected to the steam inlet 41, and a condensed water discharge pipe 44 provided with a steam trap 45 is connected to the condensed water outlet 42.

With the above configuration, when the indirect steam humidifier A according to the present embodiment is operated, primary steam is introduced from the steam inlet 41 of the heat exchanger 4, and the steam is passed through the steam passage R while being heated. The heat exchanges heat with the clean water W in the inside, the water is heated and evaporated, and the space requiring humidification can be humidified with clean steam. The steam after the heat exchange becomes condensed water and is discharged through the condensed water outlet 42.

In addition, even if the operation is performed for a long time and the impurity concentration in the heating tank 1 is increased and the scale S is deposited and adheres to the outer surface of the heat exchanger 4, the heat exchanger 4 is simply cylindrical. Because of the outer surface shape, the work of removing the adhered scale can be performed very easily and in a short time. Moreover, as described above, the ceiling wall 1a and the bottom wall of the heating tank 1
Since 1b is detachable, maintainability including scale removal work is further improved.

As described above, in this embodiment, the expensive heat exchanger 4 can be used for a long time without replacement,
It is also very cost effective.

In general, the heat transfer performance per unit area of the heat transfer surface of the heat exchanger is determined by the heat conductivity of the partition and the surface heat transfer coefficient between the partition surface and the heat medium.

In the present embodiment, the heat exchanger 4 is constituted by the cylindrical heat transfer tube 40, but the material of the heat transfer tube 40 and the thickness of the partition wall are determined by the coil described in the section of "Prior Art". The heat conductivity of the partition wall and the surface heat transfer coefficient on the side in contact with water have substantially the same values as those of the coil shape.

Further, the inner surface side of the steam flow path R, that is,
On the side in contact with the steam, the cross-sectional area of the steam flow path R is determined so that the passing velocity of the steam, which is an important factor in determining the surface heat transfer coefficient, becomes an appropriate value. The same heat-passing performance as that of the above is obtained. In the present embodiment, the steam flow rate is approximately 10 to 60 m /
sec).

As another form of the heat exchanger 4, for example, a heat exchanger having a configuration shown in FIG. 3 can be used.

That is, the partition member M is spirally mounted in the thick peripheral wall of the heat transfer tube 40 formed in a hollow shape, and the steam flow path R is formed in a spiral shape. Reference numerals 42 are provided at positions near the two ends of the heat transfer tube 40 so as not to overlap with the partition member M. Note that the partition member M has a band shape or a rod shape.

Using such a heat exchanger 4, in addition to the effect that the scale removing operation is easy and the maintainability is improved, the cross-sectional area of the steam passage R is reduced, and a spiral shape having a gentle gradient is formed. Therefore, the passage speed of the steam can be increased, and the steam flow is vigorously stirred in the steam passage R, so that the turbulent state is promoted and the surface heat transfer performance is improved.

Further, since the process from the generation of condensed water to the enlargement of droplets is promoted by the effect of centrifugal force when passing through the spiral steam passage R, the surface heat transfer performance is improved.

Next, an indirect steam humidifier B according to another embodiment will be described with reference to FIG. Here, the heat exchanger 4 shown in FIG. 3 is used.

In the embodiment shown here, the heating tank 1
The bottom wall 1b is formed in a funnel shape, and a water supply / drain port 10 is provided substantially at the center thereof.

Further, with the supply / drain port 10 as a starting end, the connecting pipe 13 is extended downward, and a drain pipe main body 50 is connected to the end of the connecting pipe 13 in a substantially orthogonal state.
And the drain pipe main body 50 constitute the drain pipe 5.

A drain valve 6 'is attached to the drain pipe body 50, and the drain valve 6' is a ball valve type driven by a motor with a speed reducer. The opening / closing drive is controlled by a control device (not shown). The opening / closing passage is rotated by rotating the valve seat 60 so that the clean water in the heating tank 1 can be drained as needed.

In the present embodiment, the water supply / drain port 10
A water supply pipe 7 is connected to a position between the water supply valve 7 and the drain valve 6 ′, and a distal end of the water supply pipe 7 extends toward the drain valve 6 ′. It is configured to face the drain valve 6 'at a fixed interval.

That is, the drainage pipe 5 is bent at a position between the water supply / drain port 10 and the drainage valve 6 ', which is the start end thereof, to form a substantially L-shape. From 51, it penetrates into the drain pipe 5, and the tip of the water supply pipe 7 extends horizontally to the drain valve 6 '. In this embodiment, the bent portion 51 having a substantially L shape is used.
In fact, since the vertical portion of the connecting pipe 13 and the horizontally disposed drain pipe main body 50 are connected in a communicating state in a straight line, the bag-shaped end 52 of the drain pipe main body 50 is connected to the drain valve 6 ′. A water supply pipe 7 is formed so as to protrude on the opposite side,
Are connected in a penetrating state, and the lower part of the connection pipe 13 has a double pipe structure with the upstream part of the drain pipe main body 50 and the downstream part of the water supply pipe 7.

A water supply valve 8 provided in the middle of the water supply pipe 7 communicates with a water level detection sensor 30 disposed in the level gauge 3 by a signal line, so that the clean water level in the heating tank 1 is within a certain range. Is opened and closed based on the detection signal from the water level detection sensor 30 so that

According to the present embodiment, when the clean water in the heating tank 1 is heated and evaporated by the heat exchanger 4, the steam is discharged from the steam spray pipe 2. As a result, the clean water in the heating tank 1 decreases and the water level decreases, but the water level detection sensor 30 of the level gauge 3 connected to the heating tank 1 detects the lower limit water level, and based on the detection signal, the water supply valve 8 can be opened and replenished.

As shown in FIG. 4, the supply water flows out of the water supply port 70 of the water supply pipe 7 toward the valve seat 60 of the drain valve 6 '. During the operation of the indirect steam humidifier A, the drain valve 6 'is closed, so that make-up water is supplied to the supply / drain port as shown by the arrow f in the figure.
It goes to 10 and flows into the heating tank 1 through the water supply / drain opening 10.

When the water level detection sensor 30 detects that the clean water has reached the upper limit water level, the water supply valve 8 is closed and supply is stopped based on the detection signal.

This water supply operation is repeatedly performed while the indirect steam humidifier A continues to operate.

A control device (not shown) periodically or in accordance with the impurity concentration in the heating tank 1.
The humidification operation is stopped, the drain valve 6 'is opened, and the water in the heating tank 1 is discharged. When the draining operation is completed, the drain valve 6 'is closed, the water supply valve 8 is opened, and the makeup water is supplied to the heating tank 1
The water level is detected by a water level sensor
When 30 is detected, the water supply valve 8 is closed by the detection signal, and the humidifying operation is restarted.

While repeating this operation, the valve seat of the drain valve 6 '
Since clean make-up water repeatedly passes through the pipeline leading to the water supply and drain port 60, the valve seat 60 of the drain valve 6 'and the water supply and drain port
10. The inside of the pipes of both pipes will be washed repeatedly by the jet of makeup water.

In the drawing, S is a scale, and a part of the scale S generated in the heating tank 1 is disposed between the water supply / drain port 10 and the drain valve 6 'while the water supply valve 8 is closed. However, as described above, during the operation of the indirect steam humidifier B, the operation in which the water supply valve 8 is opened and the washing water flows in is repeated, so that the mixed scale S is heated. The water flows back into the tank 1, and the vicinity of the drain valve 6 'can be maintained in a clean state.

As described above, according to this embodiment, even if the scale S adheres to the surface of the heat exchanger 4, it is easy to remove the scale S, and the scale S plugs the drain valve 6 '. There is no danger of lowering the drainage capacity or causing malfunction of the valve.

In FIG. 4, reference numeral 2 denotes a steam spray pipe, 45 denotes a steam trap, and 46 denotes a steam control valve.

Reference numeral 47 denotes a condensed water storage part provided in the middle of the condensed water discharge pipe 44, which is housed and disposed in a can 48 provided in the middle of the water supply pipe 7. Then, both constitute an auxiliary heat exchanger, and the water in the supplied can 48 and the condensed water storage section are formed.
Heat exchange is possible with the condensed water in 47.

According to this configuration, when the primary steam that has been heat-exchanged and radiated by the heat exchanger 4 becomes condensed water, the condensed water is stored in the condensed water storage part 47 by the dropping action due to gravity and the primary steam flow supplied later. The condensed water of the primary steam can be immediately conveyed and discharged to the condensed water discharge pipe 44 by the steam trap 45 provided on the downstream side of the condensed water storage part 47, so that the condensed water of the primary steam can stay inside the heat exchanger 4. Therefore, there is no possibility that the heat exchange capacity is reduced.

Furthermore, the temperature of the condensed water can be lowered by exchanging heat between the supplied water in the can 48 and the condensed water in the condensed water storage unit 47. For example, the steam trap 45 is a thermostatic trap. In this case, the operation performance can be improved, and the humidifying makeup water can be preheated by the exhaust heat of the condensed water, so that the heat exchange rate can be significantly increased.

The other components of the indirect steam humidifier B according to this embodiment shown in FIG. 4 are substantially the same as those of the previous embodiment, and therefore, the description thereof is omitted here.

[0056]

The present invention is embodied in the above-described embodiment, and has the following effects.

According to the present invention, the heating tank includes a heating tank for storing water for evaporation therein, and a heat exchanger provided in the heating tank and using steam as a heating source. In the indirect steam humidifier configured to heat and evaporate water in the tank and discharge generated steam, the heat exchanger is formed by a tubular heat transfer tube, and a thick peripheral wall of the heat transfer tube is hollow. The heat exchanger is formed by forming a steam flow passage, and further providing connection ports communicating with the steam flow passage near both ends of the heat transfer tube, one being a steam inlet and the other being a condensate outlet. Has a simple outer surface shape and can be easily removed even when scales or the like are stuck. Then, the removal operation can be performed in a short time by anyone, not by a skilled person.

Further, since the descaling operation can be easily performed, the frequency of replacing the heat exchanger itself is reduced, and the economic effect is significantly increased.

According to the second aspect of the present invention, the partition member is spirally mounted in the thick peripheral wall of the hollow heat transfer tube, and the steam flow path is formed in a spiral shape. In addition to the effect, the cross-sectional area of the steam passage is reduced and the steam passage has a helical shape with a gentle slope, so that the steam passing speed can be increased.

In addition, the steam flow is vigorously stirred in the steam passage, the turbulent state is promoted, and the process from the generation of condensed water to the enlargement of droplets is carried out by centrifugation when passing through the spiral steam passage. Because of the force effect, the surface heat transfer performance is further improved and the performance of the heat exchanger is enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an indirect steam humidifier according to an embodiment.

FIG. 2 is an explanatory diagram of a heat exchanger according to an embodiment.

FIG. 3 is an explanatory diagram of another embodiment of the heat exchanger.

FIG. 4 is a schematic explanatory view of an indirect steam humidifier according to another embodiment.

FIG. 5 is a schematic explanatory view showing an example of a conventional indirect steam humidifier.

[Explanation of symbols]

 A, B Indirect steam humidifier S Scale R Steam flow path 1 Heating tank 4 Heat exchanger 40 Heat transfer tube 41 Steam inlet (connection port) 42 Steam outlet (connection port)

Claims (2)

[Claims] 1. A heating tank for storing water for evaporation therein, and a heat exchanger disposed in the heating tank and using steam as a heating source, wherein the water in the heating tank is heated and evaporated. In the indirect steam humidifier configured to be able to discharge generated steam, the heat exchanger is formed by a tubular heat transfer tube, and a thick peripheral wall of the heat transfer tube is formed in a hollow shape to form a steam flow path. None,
An indirect steam humidifier, wherein connection ports for communicating with the steam flow path are provided near both ends of the heat transfer tube, one of which is a steam inlet and the other is a condensed water outlet. 2. A heat transfer tube formed in a hollow shape and having a thick peripheral wall therein.
2. The indirect steam humidifier according to claim 1, wherein the partition member is spirally attached, and the steam flow path is spirally formed.